Search

Introduction: Vitiligo, an autoimmune disorder marked by skin depigmentation, is closely linked to immune dysregulation, including T cell infiltration and pro-inflammatory cytokines. This study explores the potential of baricitinib, a JAK-STAT inhibitor, in promoting repigmentation in vitiligo lesions by modulating immune responses., Methods: Using a mouse model of vitiligo induced by hydroquinone, we assessed the effects of baricitinib treatment on lesion repigmentation, CD8  +  T cell infiltration, T cell populations, and serum TNF-α levels. Immunostaining, flow cytometry, and ELISA were used to analyse these parameters., Results: Baricitinib treatment significantly reduced CD8  +  T cell infiltration in the skin, lowered serum TNF-α levels, and decreased both CD4  +  and CD8  +  T cell populations in the blood. Remarkably, these immune modulations correlated with notable repigmentation of the lesions., Conclusion: Baricitinib effectively reduces inflammation and T cell infiltration, suggesting it as a promising therapeutic for vitiligo. These findings highlight its potential to modulate immune responses and restore skin pigmentation in vitiligo patients., Competing Interests: Declarations. Conflit of interest: The authors declare no conflict of interest. Ethical approval: The study was approved by Institutional Animal Ethics Committee (PU/45/99/CPCSEA/IAEC/2020/423). The experimental protocols were carried out in accordance with the regulations set by Committee for Control and Supervision of Experiments on Animals for the Purpose of Scientific Research (CCSEA)., (© 2025. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Despite suppressive antiretroviral therapy (ART), HIV-1 persists in latent reservoirs that seed new HIV infections if ART is interrupted, necessitating lifelong therapy for people with HIV. Activation of latent HIV during ART could improve recognition and elimination of infected cells by the immune system. Protein kinase C (PKC) isozymes increase HIV transcription and hence are potential latency reversal agents. However, the clinical utility of PKCs for this application is limited due to toxicity, which is poorly understood. Our studies showed that PKC activation with multiple classes of agonists leads to widespread platelet activation, consistent with disseminated intravascular coagulation, at concentrations that were similar to those required for T-cell activation. Differential expression analysis indicated that PKC-ε and PKC-η isoforms are expressed at high levels in human CD4+ T cells but not in platelets. Using structure-based drug design, we developed a novel PKC agonist, C-233, with increased selectivity for PKC-ε. C-233 increased both supernatant HIV RNA and p24 expression ex vivo after treatment of CD4+ T cells from ART-suppressed people with HIV. C-233 was 5-fold more potent for T-cell activation relative to platelet activation. Our studies support the use of structure-based drug design to create selective novel PKC agonists for the safe activation of HIV reservoirs and improved tolerability., Competing Interests: I have read the journal's policy and the authors of this manuscript have the following competing interests: At the time of this work, all authors, with the exception of SD and JL, were employees and shareholders of Gilead Sciences, Inc. RM, JK, HY, BS, HT, EH, and JPM are inventors on PKC agonist–related patent applications. Authors SD and JL declare that no competing interests exist., (Copyright: © 2025 Irrinki et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Background: CD4 + T-cell lymphocytopenia and immune dysfunction are factors that drive the onset and persistence of Kaposi sarcoma (KS) in people with (PWH) and without HIV. Standard chemotherapy agents for KS can contribute to increasing CD4 + T cell lymphocytopenia. IL-7 is a cytokine that is essential in T-cell development, proliferation and homeostasis. In PWH, IL-7 administration leads to increased numbers of circulating central memory and naïve T-cell phenotypes., Methods: In this multicenter phase I study with a 3+3 dose escalation design, participants with KS with or without HIV received up to four intramuscular injections of IL-7 (NT-I7) every 9 weeks. The primary endpoint of the study was to evaluate safety over three escalating dose levels (DL) of NT-I7 (DL1:480 µg/kg, DL2: 960 µg/kg and DL3: 1200 µg/kg) and identify a maximum tolerated dose. Secondary endpoints included evaluation of antitumor activity per the modified AIDS Clinical Trials Group Criteria and assessment of the effect of NT-I7 on the kinetics of CD4 + and CD8 + T-cells., Results: Eight cisgender male participants (five with HIV infection) were enrolled. Six participants were treated at DL1, and two were treated at DL2. The study was closed to accrual after enrolment of the second participant on DL2 due to termination of study funding. Four of the eight participants (three in DL1 and one in DL2) completed all four doses of the NT-I7. With regard to treatment-emergent adverse events (AEs), all participants had + and CD8 + T-cell counts increased among all participants following administration of NT-I7. Participants who experienced a response had HIV and lower CD4/CD8 ratio at baseline and throughout the study as compared with those who did not have KS response to NT-I7., Conclusions: Preliminary data demonstrate safety and activity of IL-7 in patients with KS and activity specifically among individuals HIV-associated KS., Trial Registration Number: NCT04893018., Competing Interests: Competing interests: RR, KL and RY report receiving research support from Celgene (now Bristol Myers Squibb), from CTI BioPharma (a Sobi Company), PDS Biotech, and Janssen Pharmaceuticals through CRADAs with the NCI. RR, KL and RY report receiving drug for a clinical trial from Merck through a CRADA with the NCI. RR, KL and RY report receiving drug for a clinical trial from EMD-Serano and Eli Lilly through a CRADA at the NCI. RY reports receiving preclinical material from Lentigen Technology through a CRADA or MTA with the NCI. MPM reports receiving research support from Roche through a CTA with Fred Hutchinson Cancer Research Center. TSU is currently employed by Regeneron Pharmaceuticals. TSU and RY are coinventors on US Patent 10,001,483 entitled 'Methods for the treatment of Kaposi’s sarcoma or KSHV-induced lymphoma using immunomodulatory compounds, and uses of biomarkers.' RY is also a coinventor on patents on a peptide vaccine for HIV and on the treatment of Kaposi sarcoma with IL12, and an immediate family member of RY is a coinventor on patents related to internalization of target receptors, on KSHV viral IL-6, and on the use of calreticulin and calreticulin fragments to inhibit angiogenesis. All rights, title, and interest to these patents have been or should by law be assigned to the US Department of Health and Human Services; the government conveys a portion of the royalties it receives to its employee inventors under the Federal Technology Transfer Act of 1986 (P.L. 99-502). No potential conflicts of interest were disclosed by the other authors. TSU name as a coinventor on US Provisional Patent Application 18/310,649, KSHV Oncoprotein Antigens and Epitodes for Expanding Antigen Specific T-cells., (© Author(s) (or their employer(s)) 2025. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ Group.)

Malignant T-cell transformation after chimeric antigen receptor (CAR) T-cell therapy has been described, but the contribution of CAR integration to oncogenesis is not clear. Here we report a case of a T-cell lymphoma harboring a lentiviral integration in a known tumor suppressor, TP53 , which developed in a patient with multiple myeloma after B-cell maturation antigen (BCMA) CAR T-cell therapy., (Copyright © 2025 Massachusetts Medical Society.)

How pathogens inhibit transplant tolerance remains unclear. Here, we found that Pseudomonas aeruginosa infection, but not other common bacterial respiratory infections, increases antibody-mediated rejection (AMR) risk in recipients of lung transplants. To explore this relationship, we performed orthotopic lung transplants in mice, infected recipients with P. aeruginosa , and observed for the development of AMR. Intravital two-photon microscopy showed that P. aeruginosa rapidly invaded bronchial-associated lymphoid tissues, which resulted in acute lymphocytotoxicity, including the death of forkhead box P3 (Foxp3) + CD4 + T cells that are required to suppress AMR. P. aeruginosa -mediated AMR required expression of the type III secretion system (T3SS), which injects exotoxins into the cell cytoplasm. Through a combination of mutagenesis and epitope tagging experiments, we revealed that T3SS exotoxin T ADP ribosyl-transferase activity was sufficient for graft-resident Foxp3 + CD4 + T cell apoptosis, leading to myeloid differentiation primary response 88 (Myd88)-dependent generation of T-box expressed in T cells (T-bet)- and C-X-C motif chemokine receptor 3 (CXCR3)-positive germinal center and memory B cells with high donor antigen avidity. We also found that T-bet + and CXCR3 + B cells were elevated in biopsies from recipients of lung transplants who were diagnosed with AMR. In mice, CXCR3 deficiency restricted to B cells or CXCR3 blockade prevented AMR despite P. aeruginosa infection. Our work has identified a previously unrecognized role of bacterial virulence in lung allograft rejection and suggests potential strategies to prevent AMR for those at high risk of P. aeruginosa infection after transplant.

Isoform sequencing (Iso-Seq) uses long-read technology to produce highly accurate full-length reads of mRNA transcripts. Visualization of individual mRNA molecules can reveal new details of transcript variation within understudied portions of mRNA, such as the 5' untranslated region (UTR). Differential 5' UTRs may contain motifs, upstream open reading frames (uORFs), and secondary structures that can serve to regulate translation or further indicate changes in promoter usage, where transcriptional control may impact protein expression levels. To begin to explore isoform variation during T-cell activation, we generated the first Iso-Seq reference transcriptome of activated human CD4 T cells. Within this dataset, we discovered many novel splice- and end-variant transcripts. Remarkably, one in every eight genes expressed in our dataset was found to have a notable proportion of transcripts with 5' UTR lengthened by over 100 bp compared to the longest corresponding UTR within the Gencode dataset. Among these end-variant transcripts, two novel isoforms were identified for CXCR5, a chemokine receptor associated with T follicular helper cell (Tfh) function and differentiation. When investigated in a model cell system, these lengthened UTR conferred reduced transcript stability and, for one of these isoforms, short uORFs introduced by the added length altered protein expression kinetics. This study highlights instances in which current reference databases are incomplete relative to the information obtained by long-read sequencing of intact mRNA. Iso-Seq is thus a promising approach to better understanding the plasticity of promoter usage, alternative splicing, and UTR sequences that influence RNA stability and translation efficiency., (© 2025. The Author(s).)

Uveitis refers to a diverse group of inflammatory diseases that affecting the uveal tract, comprising the iris, ciliary body, and choroid, with potential repercussions ranging from visual impairment to blindness. The role of autoimmunity in uveitis etiology is complex and still under investigation. CD4 + T cells intricately regulate immune responses in uveitis through their diverse subtypes: Th1, Th2, Th17, Treg (T regulatory), and Tfh (follicular T helper) cells. Each T cell subtype secretes specific cytokines with either pathogenic or protective implications in uveitis. Th1 cells, characterized by IFN-γ secretion and T-bet expression, drive type 1 immune responses against intracellular pathogens. Conversely, Th2 cells, which produce interleukin (IL)-4, IL-5, and IL-13 and express the transcription factor GATA3, mediate type 2 immune responses to larger extracellular threats like helminths. Th17 cells, generating IL-17 and IL-22 and controlled by RORγt, engage in type 3 immune responses against select pathogens. Tfh cells, releasing IL-21 and governed by Bcl6, aid B cell antibody production. Conversely, Tregs, identified by Foxp3, exert regulatory functions in immune homeostasis. This review delves into the roles of CD4 + T cell-derived cytokines in uveitis, emphasizing their intricate involvement in disease progression and resolution. Insight into these mechanisms might guide therapeutic approaches targeting CD4 + T cell responses in uveitis management., Competing Interests: Declarations. Conflict of interest: The authors declare no competing interests. Ethical approval: Not applicable. Consent to participate: Not applicable. Consent to publish: Not applicable., (© 2025. The Author(s).)

Purpose of Review: Despite suppressive antiretroviral therapy (ART), HIV-1 reservoirs persist in various cell types and tissues and reignite active replication if therapy is stopped. Persistence of the viral reservoirs in people with HIV-1 (PWH) is the main obstacle to achieving a cure. Identification and characterization of cellular and tissue HIV-1 reservoirs is thus central to the cure research. Here, we discuss emerging insights into the phenotype of HIV-1 reservoir cells., Recent Findings: HIV-1 persists in multiple tissues, anatomic locations, and cell types. Although contributions of different CD4 + T-cell subsets to the HIV-1 reservoir are not equal, all subsets harbor a part of the viral reservoir. A number of putative cellular markers of the HIV-1 reservoir have been proposed, such as immune checkpoint molecules, integrins, and pro-survival factors. CD32a expression was shown to be associated with a very prominent enrichment in HIV-1 DNA, although this finding has been challenged. Recent technological advances allow unbiased single-cell phenotypic analyses of cells harbouring total or intact HIV-1 proviruses. A number of phenotypic markers have been reported by several independent studies to be enriched on HIV-1 reservoir cells. Expression of some of these markers could be mechanistically linked to the reservoir persistence, as they could for instance shield the reservoir cells from the immune recognition or promote their survival. However, so far no single phenotypic marker, or combination of markers, can effectively distinguish HIV-infected from uninfected cells or identify all reservoir cells., Competing Interests: Declarations. Human and Animal Rights and Informed Consent: This article does not contain any studies with human or animal subjects performed by any of the authors. Conflict of Interest: The authors declare no competing interests., (© 2025. The Author(s).)

CD26 is a human T cell costimulatory molecule as well as a T cell subset marker, and the increase of CD26+ T cells in inflamed tissues and peripheral blood has been reported in diverse autoimmune diseases. In contrast, our group has previously shown that levels of circulating CD26+ T cells are decreased in patients with systemic lupus erythematosus (SLE), although the role of reduced CD26 T cell surface expression in SLE pathology remains to be elucidated. In the present study, we conducted CD26-based T cell subset analyses utilizing peripheral blood mononuclear cells from 57 SLE patients and 31 healthy adult volunteers. We show that the increase in the CD26(-) T cell population reflects the abnormal expansion of CD26(-)CD28(-) cytotoxic subsets of both CD8 T cells and CD4 T cells in SLE patients. Single-cell RNA sequencing analysis of the CD26(-)CD28(-) CD4 and CD8 T cell populations reveals unique characteristics with similarities to natural killer T cells. In addition, the level of CD26(-)CD28(-) T cells is increased in some active-stage SLE patients with renal manifestation. Meanwhile, the effect of prednisolone treatment on these populations varies from patient to patient, with levels of these cytotoxic effector populations still being elevated in some inactive-stage SLE patients. Taken together, our data suggest that analysis of these populations in SLE may be a useful tool to classify this markedly heterogeneous condition., (© The Author(s) 2024. Published by Oxford University Press on behalf of The Japanese Society for Immunology. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Tumor-reactive CD4+ T cells often accumulate in the tumor microenvironment (TME) in human cancer, but their functions and roles in antitumor responses remain elusive. Here, we investigated the immunopeptidome of HLA class II-positive (HLA-II+) endometrial cancer with an inflamed TME using a proteogenomic approach. We identified HLA-II neoantigens, one of which induced polyclonal CD4+ tumor-infiltrating lymphocyte responses. We then experimentally demonstrated that neoantigen-specific CD4+ tumor-infiltrating lymphocytes lyse target cells in an HLA-II-dependent manner. Single-cell transcriptomic analysis of the TME coupled with T-cell receptor sequencing revealed the presence of CD4+ T-cell clusters characterized by CXCL13 expression. The CXCL13+ clusters contained two subclusters with distinct cytotoxic gene expression patterns. The identified neoantigen-specific CD4+ T cells were found exclusively in one of the CXCL13+ subclusters characterized by granzyme B and CCL5 expression. These results demonstrate the involvement of tumor-reactive CD4+ T cells with cytotoxic function in immune surveillance of endometrial cancer and reveal their transcriptomic signature., (©2024 American Association for Cancer Research.)

Hepatocellular carcinoma has a high incidence and poor prognosis. In this study, we investigated the value of T-cell-related genes in prognosis by single-cell sequencing data in hepatocellular carcinoma. Twelve cases of hepatocellular carcinoma single-cell sequencing were included in the study. The high dimensional weighted gene co-expression network analysis (hdWGCNA) was used to identify gene modules associated with CD4 + T cells, CD8 + T cells and exhausted T cells. Altered signaling pathway activity in exhausted T cells was uncovered by the AUCell algorithm. xCELL, TIMER, QUANTISEQ, CIBERSORT and CIBERSORT-abs were performed to explore immune cell infiltration. Immune checkpoint inhibitor genes and TIDE methods were used to predict immunotherapy response. Finally, immunohistochemistry and real-time PCR were used to verify gene expression. The hdWGCNA algorithm identified 40 genes strongly associated with CD4 + T cells, CD8 + T cells and exhausted T cells. Seven genes were finally selected for transcriptome data modeling. The results of the three independent datasets suggested that the model had strong prognostic value. Model genes were critical factors influencing CD4 + T cell and CD8 + T cell infiltration in patients. The efficacy of PD-1 immunotherapy was higher in patients belonging to the low-risk group. Alterations in signaling pathways' activity within exhausted T cells were crucial factors contributing to the decline in immune function. Differential expression of seven genes in CD8 + T cells, CD4 + T cells and exhausted T cells were key targets for improving immunotherapy response in HCC., Competing Interests: Declarations. Competing interests: The authors declare no competing interests., (© 2025. The Author(s).)

Objective: Considering the diverse aetiologies and immunodysregulatory statuses observed in each patient with rheumatoid arthritis (RA), stratification based on peripheral blood immunophenotyping holds the potential to enhance therapeutic responses to molecular targeted therapies, biological/targeted synthetic disease-modifying antirheumatic drugs (b/tsDMARDs)., Methods: Immunophenotype analysis was conducted on a cohort of over 500 b/tsDMARDs-naïve patients using flow cytometry. Patients with RA were stratified based on their immunophenotypes, and the treatment response to each targeted therapy was evaluated. Validation was performed using an additional cohort of 183 b/tsDMARDs-naïve patients with RA., Results: Patients with RA were stratified into five clusters, two of which exhibited distinct RA phenotypes compared with controls, characterised by significant increases in CD4 + effector memory T cells re-expressing CD45RA. Notably, the effectiveness of different b/tsDMARDs varied across clusters. The group using promising b/tsDMARDs was labelled as 'expected' whereas the 'non-expected' group comprised those using others. The expected group outperformed the non-expected group with higher 26-week remission rates (39.9% vs 24.6%, p=0.0004) and low disease activity achievement (80.8% vs 60.2%, p<0.0001). Trajectory analysis showed the non-expected group's 26-week disease activity was influenced by Clinical Disease Activity Index at baseline unlike the expected group. Additionally, different molecular targeted therapies influenced the proportions of each immune cell subset variably. To validate, immunophenotyping was performed on a validation cohort. When 183 cases were grouped based on their b/tsDMARDs usage into expected/non-expected groups, the expected group had a higher remission rate (p=0.0021), further confirming the observed trend., Conclusion: Our findings offer valuable insights into the diversity of RA and potential therapeutic strategies grounded in the molecular underpinnings., (Copyright © 2024 European Alliance of Associations for Rheumatology (EULAR). Published by Elsevier B.V. All rights reserved.)

Background & Aims: Despite the success of biological therapies in treating inflammatory bowel disease, managing patients remains challenging due to the absence of reliable predictors of therapy response., Methods: In this study, we prospectively sampled 2 cohorts of patients with inflammatory bowel disease receiving the anti-integrin α4β7 antibody vedolizumab. Samples were subjected to mass cytometry; single-cell RNA sequencing; single-cell B and T cell receptor sequencing (BCR/TCR-seq); serum proteomics; and multiparametric flow cytometry to comprehensively assess vedolizumab-induced immunologic changes in the peripheral blood and their potential associations with treatment response., Results: Vedolizumab treatment led to substantial alterations in the abundance of circulating immune cell lineages and modified the T-cell receptor diversity of gut-homing CD4 + memory T cells. Through integration of multimodal parameters and machine learning, we identified a significant increase in proliferating CD4 + memory T cells among nonresponders before treatment compared with responders. This predictive T-cell signature demonstrated an activated T-helper 1/T-helper 17 cell phenotype and exhibited elevated levels of integrin α4β1, potentially making these cells less susceptible to direct targeting by vedolizumab., Conclusions: These findings provide a reliable predictive classifier with significant implications for personalized inflammatory bowel disease management., (Copyright © 2025 The Authors. Published by Elsevier Inc. All rights reserved.)

Here we review recent data on how animal viruses alter the T cell dynamics, and how stressed T cell populations alter viral disease outcomes. The CD4/CD8 ratio of T cells is regulated by the thymus well into adulthood, and determined by both host genetics and environmental exposures. Human and animal data now show many chronic viral infections interact with this ratio and Immune Health Grades, but this raises new questions and justifies new experimental systems. Immune Health Grades and the ratio generally can quantify subtle immunodeficiency for viral infections. Whether or not an animal recovers from a viral infection, and how carcinogenisis proceeds for certain oncogenic viral infections can now be traced back to how "stressed that animal's immune system is as judged by a low CD4/CD8 ratio or elevated Immune Health Grade. We provide this review to encourage basic science virologists using animal models and veterinary virologists to further explore the interactions between the CD4/CD8 T cell ratio and viruses to improve both human and veterinary health., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Dr. Striker is a consultant for Pfizer, Salus Discovery and Voiant., (Copyright © 2024. Published by Elsevier Inc.)

Myasthenia gravis (MG) presents with symptoms that significantly affect patients' daily lives. Long-term MG therapies may lead to substantial side effects, predominantly due to prolonged immune suppression. Sirt6, which plays a vital role in maintaining cellular homeostasis and is recognised for its involvement in cytokine production in immune cells, has not yet been explored in relation to MG. PBMCs and CD4 + T cells were isolated from blood samples. RT-qPCR, western blot and ELISA were used to assess the expression of target genes and proteins. Flow cytometry was used to identify the subsets of T helper cells. Co-IP was conducted to investigate the interaction between USP9X and Sirt6. Finally, the experimental autoimmune myasthenia gravis (EAMG) model was established. In MG patients, Sirt6 levels were downregulated compared to healthy controls. Sirt6 overexpression led to a reduction in Th1 and Th17 cell populations while augmenting Treg cells in PBMCs. USP9X interacted with Sirt6, leading to its deubiquitination and stabilisation. Elevated Sirt6 levels subsequently mitigated symptoms in the EAMG model. The stabilisation of Sirt6, mediated by USP9X, has been found to relieve symptoms of EAMG by influencing the subtypes of T helper cells. This highlights the promising potential of Sirt6 as a viable therapeutic target in the treatment of MG., (© 2024 John Wiley & Sons Australia, Ltd.)

Immune checkpoint inhibitor (ICI)-associated myocarditis is a rare but potentially fatal immune-related adverse event. Previously, we reported a case of ICI-associated myocarditis with elevated autoantibodies to 4E-binding protein 3 (4E-BP3). Recent studies have suggested that 4E-BP3 may play an important role in tumor development. However, its role in cardiac diseases including myocarditis is unknown. We investigated the role of 4E-BP3 in an autoimmune myocarditis mouse model. Myocarditis was induced in wild-type and 4E-BP3 knockout mice by immunization with murine α-myosin peptide. 4E-BP3 gene expression was upregulated in the heart of myocarditis mouse. We found that genetic deletion of 4E-BP3 attenuated myocardial inflammation, reduced fibrosis area, and improved cardiac function in myocarditis mice. Studies in bone marrow-chimeric mice demonstrated that immune cell-derived 4E-BP3 plays a pivotal role in the pathogenesis of myocarditis. Immune cell transfer experiments revealed that 4E-BP3 deficiency in dendritic cells and CD4 + T cells decreased disease severity in recipient mice. Furthermore, dendritic cells that were deficient in 4E-BP3 exhibited a diminished capacity to produce IL-6 and IL-1β. Naive CD4 + T cells lacking 4E-BP3 had a reduced ability to differentiate into T-helper (Th)1 and Th17 cells. These findings suggest that 4E-BP3 in dendritic cells and CD4 + T cells may be critically involved in the pathogenesis of α-myosin-specific T cell-mediated myocarditis. Thus, 4E-BP3 could be a possible therapeutic target for myocarditis., Competing Interests: Declarations. Conflict of interest: The authors have no relevant financial or non-financial interests to disclose. Ethical approval: After receiving approval from the Institutional Animal Experiment Committee of the University of Tsukuba (approved number: 18-447), animal experiments were carried out in accordance with the Guide for the Care and Use of Laboratory Animals published by the US National Institutes of Health, the Regulation for Animal Experiments in the University of Tsukuba, and the Fundamental Guideline for Proper Conduct of Animal Experiments and Related Activities in Academic Research Institutions under the jurisdiction of the Ministry of Education, Culture, Sports, Science and Technology of Japan. All animal studies have been performed in accordance with the ethical standards laid down in the 1964 Declaration of Helsinki and its later amendments., (© 2024. Springer-Verlag GmbH Germany, part of Springer Nature.)

Background: Most of the investigations related to inflammasome activation during HIV infection have focused on the receptor NLRP3 and innate immune cells such as monocytes/macrophages. However, during the past years, inflammasome activation has also been explored in lymphocytes, and novel sensors, other than the NLRP3, have been shown to play a role in the biology of these cells. Here, we hypothesized that NLRP1 may be involved in CD4+ T cell dysregulation in people living with HIV (PLWH), therefore contributing to chronic inflammation and to the pathogenesis of non-HIV-associated diseases., Methods: The activation of NLRP1 in CD4+ T cells was assessed ex-vivo and in-vitro by the meaning of anti-CD3/anti-CD28 and Talabostat/Val-boroPro (VbP) response., Results: Our results showed that the NLRP1 inflammasome was activated in PLWH CD4+ T cells, and that the stimulation of CD4+ T cells resulted in increased response to anti-CD3/anti-CD28 and VbP. Functional variants in NLRP1 significantly affected the level of inflammatory dysregulation of CD4+ T cells, therefore explaining at least in part the association with CD4+ T-mediated diseases., Conclusion: PLWH CD4+ T cells are more prone to IL-1β release and pyroptosis, therefore contributing to chronic inflammation.

Background: Rubber accelerators are used in the vulcanization of rubber. However, rubber accelerators for example tetraethylthiuram disulfide (TETD) and zinc diethyldithiocarbamate (ZDEC) may cause contact allergy. Concomitant reactions between ZDEC and TETD have been observed in patients which could be explained by co- or cross-reactivity., Objectives: To investigate cross-reactivity between TETD and ZDEC and vice versa., Methods: Groups of mice were sensitized with TETD or ZDEC based on reported EC3-values. Proliferation of lymphocytes were measured on day 5. To test cross-reactivity, mice were sensitized and challenged 3 weeks later with TETD or ZDEC. The inflammatory response was measured by changes in ear thickness and the proliferative response in CD4 + and CD8 + T cells in the submandibular and cervical draining lymph nodes., Results: Sensitization of mice with doses of ZDEC 3%, TETD 5.6% or TETD 16.2% induced significant increased ear thickness and proliferation of CD4 + and CD8 + T cells. Challenge with ZDEC or TETD in these groups induced significant increased ear thickness. Challenge with ZDEC in mice sensitized to TETD 5.6% or TETD 16.2% induced significant increased proliferation of CD4 + and CD8 + T cells., Conclusions: We show cross-reactivity between TETD and ZDEC. Patients sensitized to TETD or ZDEC should avoid exposure to both ZDEC and TETD., (© 2024 The Author(s). Contact Dermatitis published by John Wiley & Sons Ltd.)

Background: A thorough understanding of immune-oncology and molecular medicine has been vital in the development of cell therapeutics. At the basis of this translational research and its future implementation into a medicinal product, lies the availability of pure and viable cell populations. Currently, FACS and magnetic bead isolation are successfully used but suffer to fulfill all requirements. FACS is costly and difficult to upscale due to the limitation of shear stress, especially fragile, cells can handle. Therefore, magnetic bead isolation is often used as it is gentler, but it lacks the multiparametric aspect to isolate more complex cellular profiles., Aims: We aim to develop a versatile technology able of multi marker detection and isolation of complex cell types with high purity, viability and throughput., Methods: We have developed a gentle sorting mechanism based on a jet flow created by micro vapor bubbles, enabling a closed microfluidic cell isolation platform capable of multiparametric sorting with high viability, purity and throughput. In this work we compared the purity, recovery and viability of sorted CD4+ CD14- cells to magnetic isolation, most often used for other cell manufacturing approaches. Futhermore, we cultured the sorted cells of both isolation strategies and compared their growth curve and expression of activation-induced IL2 and IFN-γ., Results: We demonstrate that this tool can achieve a pure population of CD4+ CD14- cells with high viability after sorting without compromising the recovery. On top of the viability also the growth and activation potential of sorted cells is unhampered by comparison to the benchmark gentle magnetic isolation., Conclusions: Our technology allows for the development of a compact system which sets it apart from other efforts intended to create automated cell therapeutic solutions., Competing Interests: Declaration of Competing Interest There are no conflicts of interest., (Copyright © 2024 International Society for Cell & Gene Therapy. Published by Elsevier Inc. All rights reserved.)

Systemic sclerosis (SSc) is characterized by intractable multiorgan fibrosis caused by vascular and immune dysfunction. Currently, effective therapeutic options for patients with SSc are limited. Nitrate, an abundant nutrient in the diet, has been demonstrated to be preventative and therapeutic for several diseases. To determine whether nitrate can slow or reverse SSc progression, topical application of nitrate delivered by dissolving microneedles was used to treat a bleomycin-induced dermal fibrosis mouse model. In this study, nitrate considerably attenuated dermal thickness, stiffness, and collagen deposition. Bulk RNA sequencing of skin revealed that Cd4 was a key hub gene in SSc nitrate therapy. In addition, bleomycin-induced cytokines and chemokines were inhibited by nitrate, and CD4 + T cells infiltration markedly declined. Il4, Il6, Il13, and Tgfb expressions in CD4 + T cells isolated from skin biopsies also significantly decreased. Mechanistically, Il1rl1, a type 2 immune response inducer, was markedly repressed in isolated CD4 + T cells and dermal tissues after nitrate treatment. Remarkably, compared with wild-type mice, mice lacking Il1rl1 showed impaired transcriptional profiles after intradermal bleomycin injection. Adoptive transfer of ST2 + CD4 + T cells promoted bleomycin-induced Rag2 -/- mice dermal fibrosis. Collectively, these findings demonstrate that nitrate targeting ST2 + CD4 + T cells is an effective therapeutic option for SSc., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Improved vaccination strategies for tuberculosis are needed. Intravenous (i.v.) delivery of live attenuated Mycobacterium bovis BCG provides protection against Mycobacterium tuberculosis (Mtb) in macaques but poses safety challenges. Here we genetically engineered two strains, BCG-TetON-DL and BCG-TetOFF-DL, to either induce or inhibit expression of two phage lysin operons, respectively, upon tetracycline exposure. We show that lysin expression kills BCG in vitro, in infected macrophages, and following infection of immunocompetent (C57BL/6) and immunocompromised (SCID) mice. Modified BCG elicited similar immune responses and provided similar protection against Mtb challenge as wild-type BCG in mice. In macaques, cessation of tetracycline treatment reduced i.v.-administered BCG-TetOFF-DL numbers. Intravenous BCG-TetOFF-DL increased pulmonary CD4 T-cell responses compared with wild-type BCG-induced responses and provided robust protection against Mtb challenge. Sterilizing immunity occurred in 6 of 8 macaques compared with 2 of 8 wild-type BCG-immunized macaques. Thus, a 'kill-switch' BCG strain provides additional safety and robust protection against Mtb infection., Competing Interests: Competing interests: S.E. and D.S. are inventors on a pending patent application (U.S. Serial No. 62/959,485) related to the use of the kill-switch BCG strains described in this paper. The other authors declare no competing interests., (© 2025. The Author(s), under exclusive licence to Springer Nature Limited.)

Autoreactive, aberrantly activated lymphocytes that target myelin antigens in the central nervous system (CNS) are primary drivers of the autoimmune disease multiple sclerosis (MS). Proliferating cells including activated lymphocytes require deoxyribonucleoside triphosphates (dNTPs) for DNA replication. dNTPs can be synthesised via the de novo pathway from precursors such as glucose and amino acids or the deoxyribonucleoside salvage pathway from extracellular deoxyribonucleosides. Deoxycytidine kinase (dCK) is the rate-limiting enzyme in the salvage pathway. In prior work, we showed that targeting dCK with the small molecule inhibitor TRE-515 limits clinical symptoms in two myelin oligodendrocyte glycoprotein (MOG)-induced experimental autoimmune encephalomyelitis (EAE) mouse models of MS and decreases the levels of activated CD4 T and B lymphocytes in vivo. However, whether targeting dCK limits disease in additional EAE models and how targeting dCK directly impacts activated and proliferating CD4 T and B cells has yet to be determined. Here, we show that dCK is activated in the lymph nodes and spleen in an EAE model induced by amino acids 139-151 of the proteolipid protein (PLP 139-151 ) that is driven by CD4 T and B cells and is characterised by acute disease followed by disease remission. Treating this model with TRE-515 limits clinical symptoms and decreases the levels of activated CD4 T and B cells. In culture, CD4 T and B cells induce deoxyribonucleoside salvage following activation, and TRE-515 directly blocks CD4 T and B cell activation-induced proliferation and activation marker expression. TRE-515 decreases deoxycytidine triphosphate (dCTP) and deoxythymidine triphosphate (dTTP) pools and increases the length of time cells spend in S phase of the cell cycle without inducing a replication stress response in B cells. Our results suggest that dCK activity is required to supply needed dNTPs and to enable rapid cell division following lymphocyte activation against autoantigens in EAE mouse models., (© 2024 John Wiley & Sons Ltd.)

The nature of vaccine response inferiority is not well studied in children living with HIV (CLHIV). The authors investigated Hepatitis B Virus (HBV) and Diphtheria/Pertussis/Tetanus toxoid (DPT) vaccination responses following primary immunization in CLHIV (n = 42) and healthy controls (HC) (n = 38) and the effect of an additional vaccine dose. Antibody responses, CD4 and HBV-specific T/B cells were analysed using CMIA/ELISA and flow-cytometry. CLHIV had significantly lower baseline median antibody titres for all vaccines than HC (p <0.02). Differential seroprotection rates observed in CLHIV were, 4.8% for pertussis; 9.5% for HBV; 26.2% for diphtheria and 66.7% for tetanus. WHO staging significantly influenced anti-HBs levels (p = 0.0095). HBsAg-specific CD4+T-cells were significantly higher in CLHIV than HC (p = 0.042). An additional vaccine dose (HBV and Tdap) conferred a higher protection rate for tetanus and diphtheria (p <0.040) in CLHIV. These findings suggest that CLHIV exhibit a hierarchy of vaccine responses affecting antibody levels and protection rate, which was rescued by administering additional vaccine dose., Competing Interests: Declarations. Conflict of Interest: None., (© 2024. The Author(s), under exclusive licence to Dr. K C Chaudhuri Foundation.)

Background: Anti-3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGCR)-positive immune-mediated necrotising myopathy (IMNM) is characterised by the presence of IgG autoantibodies against HMGCR and a strong association with specific HLA-DR alleles. Although these findings implicate HMGCR-specific CD4 + T-cells in the disease's pathogenesis, no such cells have been described. In this study, we aimed to identify and characterise HMGCR-reactive CD4 + T-cells and assess their presence in affected muscle tissue from patients with anti-HMGCR+IMNM., Methods: Peripheral blood mononuclear cells from patients with anti-HMGCR+IMNM (n=10) and dermatomyositis (DM; n=10) were stimulated with HMGCR protein and peptides identified using a natural antigen processing assay (NAPA; n=6). CD4 + T-cell activation was assessed by CD154 upregulation via flow cytometry. T-cell receptor β(TCR) sequencing was performed on paired HMGCR-reactive T-cells and muscle biopsy tissue (n=5)., Results: CD4 + T-cell responses to HMGCR protein were higher in patients with anti-HMGCR+IMNM compared with DM (median 0.06 vs 0.00, p=0.0059). These responses were enriched in Th1-Th17 cells, and when present, they positively correlated with anti-HMGCR antibody levels (r 2 =0.89, p=0.0012). NAPA revealed convergent presentation of seven HMGCR core peptides, with substantial overlap in the peptide repertoires between patients. These HMGCR peptides elicited robust CD4 + T-cell responses, with 9/10 anti-HMGCR+IMNM patients responding to at least one peptide, compared with 1/10 DM (p=0.0003). Analysis of HMGCR-reactive TCRs β yielded antigen-reactive motifs that were enriched in muscle biopsies (projection score 0.03 vs 0.63, p=0.007)., Conclusion: HMGCR-antigen-reactive CD4 + T-cells are present in the circulation and target tissue of patients with anti-HMGCR+IMNM, suggesting an active role for these cells in the pathogenesis of anti-HMGCR+IMNM., (Copyright © 2024 European Alliance of Associations for Rheumatology (EULAR). All rights reserved.)

Inducing ferroptosis in tumor cells is emerging as a strategy for treating malignancies that are refractory to traditional treatment modalities. However, the consequences of ferroptosis of immune cells in the tumor microenvironment need to be better understood in order to realize the potential of this approach. In this study, we discovered that neutrophils in chemoresistant breast cancer are highly sensitive to ferroptosis. Reduction of the acyltransferase MOAT1 in chemoresistance-associated neutrophils induced phospholipid reprogramming, switching the preference from monounsaturated fatty acids to polyunsaturated fatty acids, which increased their susceptibility to ferroptosis. Ferroptotic neutrophils secreted PGE2, IDO, and oxidized lipids that suppressed the proliferation and cytotoxicity of antitumor CD8+ T cells. Furthermore, neutrophil ferroptosis was closely related to a distinct subset of IL1β+CXCL3+CD4+ (Fer-CD4) T lymphocytes, which were enriched in chemoresistant tumors. Fer-CD4 T cells orchestrated neutrophil ferroptosis by modulating MOAT1 expression via IL1β/IL1R1/NF-κB signaling. Moreover, Fer-CD4 T cells secreted CXCL3, IL8, and S100A9 to replenish the neutrophil pool in the tumor microenvironment. Ferroptotic neutrophils in turn fostered Fer-CD4 T-cell differentiation. In spontaneous tumorigenesis mouse models, targeting IL1β+ CD4+ T cells or IL1R1+ neutrophils broke the cross-talk, restraining neutrophil ferroptosis, enhancing antitumor immunity, and overcoming chemoresistance. Overall, these findings uncover the role of neutrophil ferroptosis in shaping the immune landscape and propose appealing targets for restoring immunosurveillance and chemosensitivity in breast cancer. Significance: In chemoresistant breast cancer, IL1β+CXCL3+CD4+ T cells mediate neutrophil ferroptosis that suppresses antitumor immunity, indicating that interfering with this intercellular cross-talk could be an attractive strategy to reverse chemoresistance., (©2024 The Authors; Published by the American Association for Cancer Research.)

Sepsis remains a life-threatening condition with high mortality rates despite current therapeutic approaches. While Huang-Lian-Jie-Du Decoction (HLJDD), a traditional Chinese medicine formula, has been historically used to treat inflammatory conditions, its therapeutic potential in sepsis and underlying mechanisms remain unexplored. This study investigated HLJDD's comprehensive effects on sepsis pathophysiology using a rat cecal ligation and puncture (CLP) model. HLJDD significantly improved survival rates and demonstrated sophisticated immunomodulatory effects through temporal regulation of the biphasic immune response characteristic of sepsis. In early sepsis, HLJDD suppressed pro-inflammatory cytokines (IL-1β, IL-6) while maintaining defensive inflammation. During late sepsis, it counteracted immunosuppression by reducing IL-10 levels and CD4 + CD25 + T cell populations while protecting CD4 + and CD8 + T cells from apoptosis. Notably, HLJDD demonstrated dynamic regulation of the gut microbiota-metabolite axis. It enhanced beneficial bacterial populations (Firmicutes, Lactobacillus) while suppressing potentially pathogenic species (Bacteroides, Parabacteroides). Metabolomic analysis revealed time-dependent modulation of short-chain fatty acids, with elevated levels at 12 h followed by strategic reduction at 18-30 h, coordinating with changes in SCFA-producing bacteria. This temporal metabolic regulation corresponded with improved intestinal barrier function and balanced immune responses. The study unveils HLJDD's novel mechanism of action through synchronized modulation of immune responses, gut microbiota, and metabolite profiles, presenting a multi-target therapeutic approach that addresses the complex pathophysiology of sepsis. These findings provide a strong foundation for further clinical investigation of HLJDD as an innovative treatment strategy for sepsis., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

T cells play a critical role in the pathogenesis of systemic lupus erythematosus (SLE). Chronic T cell receptor (TCR) signalling induces T cell exhaustion, characterised by reduced capacity to induce tissue damage. Here, we investigated the therapeutic potential of the anti-TCRβ (H57-597) monoclonal antibody (mAb) in a mouse model of SLE. Four-month-old MRL/lpr mice exhibiting SLE phenotypes received 5 weekly doses of anti-TCRβ mAb or phosphate-buffered saline (PBS) vehicle control. Subsequently, mouse survival was monitored daily. On day 1 post the final dose of treatment, SLE pathogenesis was determined using histological staining and spot urine test. T and B cell states in the brain, kidney, and secondary lymphoid organs were determined by flow cytometry. Transient treatment of anti-TCRβ mAb significantly prolonged the survival of MRL/lpr mice. Accordingly, MRL/lpr mice in the anti-TCRβ mAb group exhibited decreased proteinuria scores and minimal renal pathological damage compared to the PBS control group. Flow cytometric analysis revealed that anti-TCRβ mAb treatment resulted in a reduction in the frequencies of CD4 + T cells and CD138 + B220 lo/- plasma cells, plus an increase in Foxp3 + regulatory T cell frequency. Furthermore, CD4 + T cells from anti-TCRβ mAb treated mice exhibited elevated expression levels of PD-1 and TIM-3, with reduced IFN-γ production, indicative of an exhaustion-like phenotype. Therefore, transient administration of anti-TCRβ mAb treatment induces an exhaustion-like phenotype in CD4 + T cells, resulting in prolonged survival of MRL/lpr mice. Inducing autoreactive T-cell exhaustion holds promise as an attractive therapeutic approach for SLE., (© 2024 John Wiley & Sons Ltd.)

Background: Primary cutaneous CD4+ small/medium T-cell lymphoproliferative disorder (PCSM-LPD) is an increasingly recognized entity with heterogeneous management strategies that may include radiotherapy., Objective: Our aim was to characterize treatment options for PCSM-LPD, with a focus on the role of radiotherapy., Methods: This is a retrospective review of 46 patients seen in the Cutaneous Lymphoma Program at the University of Texas MD Anderson Cancer Center, with a clinicopathologic review consistent with PCSM-LPD. All patients were biopsied and underwent observation, topical/intralesional steroids, and/or radiotherapy. Patients were confirmed to have residual disease prior to radiotherapy., Results: All patients achieved a complete response (CR). Sixteen patients (35%) received focal radiotherapy, with a CR in 15 (94%). The CR rate following ultra-low-dose radiotherapy (4 Gy in 1-2 fractions) was 92%. There was no grade 3 toxicity after radiotherapy. Thirty patients were managed without radiotherapy, with excision and observation or steroids., Conclusion: Primary cutaneous CD4+ small/medium T-cell lymphoproliferative disorder has excellent outcomes, and management strategies may include observation following biopsy, steroids, or radiation. Ultra-low-dose radiotherapy results in excellent outcomes with limited toxicity and is effective for persistent lesions after steroidal therapy., (© 2024 the International Society of Dermatology.)

Trogocytosis is a dynamic cellular process characterized by the exchange of the plasma membrane and associated cytosol during cell-to-cell interactions. Unlike phagocytosis, this transfer maintains the surface localization of transferred membrane molecules. For example, CD4 T cells engaging with antigen-presenting cells undergo trogocytosis, which facilitates the transfer of antigen-loaded major histocompatibility complex (MHC) class II molecules from antigen-presenting cells to CD4 T cells. This transfer results in the formation of antigen-loaded MHC class II molecule-dressed CD4 T cells. These "dressed" CD4 T cells subsequently participate in antigen presentation to other CD4 T cells. Additionally, trogocytosis enables the acquisition of immune-regulatory molecules, such as CTLA-4 and Tim3, in recipient cells, thereby modulating their anti-tumor immunity. Concurrently, donor cells undergo plasma membrane loss, and substantial loss can trigger trogocytosis-mediated cell death, termed trogoptosis. This review aims to explore the trogocytosis-mediated transfer of immune regulatory molecules and their implications within the tumor microenvironment to elucidate the underlying mechanisms of immune evasion in cancers., Competing Interests: Competing interests: The authors declare no competing interests., (© 2024. The Author(s).)

It is well-known that cancer-associated fibroblasts (CAFs) are involved in the desmoplastic responses in Head and Neck Squamous Cell Carcinoma (HNSCC). CAFs are pivotal in the tumor microenvironment (TME) molding, and exert a profound influence on tumor development. The origin and roles of CAFs, however, are still unclear in the HNSCC, especially antigen-presenting cancer-associated fibroblasts (apCAFs). Our current study tried to explore the origin, mechanism, and function of the apCAFs in the HNSCC. Data from single-cell transcriptomics elucidated the presence of apCAFs in the HNSCC. Leveraging cell trajectory and Cellchat analysis along with robust lineage-tracing assays revealed that apCAFs were primarily derived from myeloid cells. This transdifferentiation was propelled by the macrophage migration inhibitory factor (MIF), which was secreted by tumor cells and activated the JAK/STAT3 signaling pathway. Analysis of the TCGA database has revealed that markers of apCAFs were inversely correlated with survival rates in patients with HNSCC. In vivo experiments have demonstrated that apCAFs could facilitate tumor progression. Furthermore, apCAFs could modulate ratio of CD4 + T cells/CD8 + T cells, such as higher ratio of CD4 + T cells/CD8 + T cells could promote tumor progression. Most importantly, data from in vivo assays revealed that inhibitors of MIF and p-STAT3 could significantly inhibit the OSCC growth. Therefore, our findings show potential innovative therapeutic approaches for the HNSCC.Significance: ApCAFs derived from myeloid cells promote the progression of HNSCC by increasing the ratio of CD4 + /CD8 + cells, indicating potential novel targets to be used to treat the human HNSCC., Competing Interests: Declarations. Ethics approval and consent to participate: All animal work was conducted in accordance with the guidelines of the Laboratory Animal Ethics Committee, School of Basic Medical Sciences, Jilin University, China, and adhered to ethical standards as per license number 2024318. The clinical samples used in this study were collected and utilized with the approval of the Ethics Committee of the School of Stomatology, Jilin University, under the approval number SJDKQ2024033. Consent for publication: Consent for publication was obtained from the participants. Competing interests: The authors declare no conflicts of interest., (© 2025. The Author(s).)

During activation, the T cell transmembrane receptor CD6 becomes incorporated into the T cell immunological synapse where it can exert both co-stimulatory and co-inhibitory functions. Given the ability of CD6 to carry out opposing functions, this study sought to determine how CD6 regulates early T cell activation in response to viral infection. Infection of CD6-deficient mice with a neurotropic murine coronavirus resulted in greater activation and expansion of CD4 T cells in the draining lymph nodes. Further analysis demonstrated that there was also preferential differentiation of CD4 T cells into T follicular helper cells, resulting in accelerated germinal center responses and emergence of high-affinity virus-specific antibodies. Given that CD6 conversely supports CD4 T cell activation in many autoimmune models, we probed potential mechanisms of CD6-mediated suppression of CD4 T cell activation during viral infection. Analysis of CD6 binding proteins revealed that infection-induced upregulation of Ubash3a , a negative regulator of T cell receptor (TCR) signaling, was hindered in CD6-deficient lymph nodes. Consistent with greater T cell activation and reduced UBASH3a activity, the T cell receptor signal strength was intensified in CD6-deficient CD4 T cells. These results reveal a novel immunoregulatory role for CD6 in limiting CD4 T cell activation and deterring CD4 T follicular helper cell differentiation, thereby attenuating antiviral humoral immunity., Importance: CD6 monoclonal blocking antibodies are being therapeutically administered to inhibit T cell activation in autoimmune disorders. However, the multifaceted nature of CD6 allows for multiple and even opposing functions under different circumstances of T cell activation. We therefore sought to characterize how CD6 regulates T cell activation in the context of viral infections using an in vivo murine coronavirus model. In contrast to its role in autoimmunity, but consistent with its function in the presence of superantigens, we found that CD6 deficiency enhances CD4 T cell activation and CD4 T cell help to germinal center-dependent antiviral humoral responses. Finally, we provide evidence that CD6 regulates transcription of its intracellular binding partner UBASH3a, which suppresses T cell receptor (TCR) signaling and consequently T cell activation. These findings highlight the context-dependent flexibility of CD6 in regulating in vivo adaptive immune responses, which may be targeted to enhance antiviral immunity., Competing Interests: A.C.-B. and C.C.B. declare no competing interests. F.L. is founder and CSO of Abcon, which focuses on CD6-ADC in the treatment of T cell lymphoma. Abcon was not involved with this study, including the experimental design, data acquisition, or interpretation.

Ethnopharmacological Relevance: Codonopsis Pilosula (CP), as a well-known traditional Chinese medicine (TCM) with medicinal and edible herb, is one of the most representative tonic Chinese herbal medicine. It has been widely used for regulating immune function with hardly any adverse effects in clinical practice., Aim of the Study: This study aimed to elucidate the immunomodulatory effect and to explore probable mechanism of Codonopsis Pilosula Extract (CPE) in septic rats., Materials and Methods: The model of septic rat was established by cecal ligation and perforation (CLP). The thymus index, spleen index and cerebral index were calculated. Histological changes were observed by Hematoxylin-eosin (HE). The positive expression of CD4 + T cells was determined in the thymus and spleen by immunohistochemical (IHC). The expression level of 24 h CD4 was corroborated by real-time quantitative polymerase chain reaction (RT-QPCR). Infectious factors, immune factors and inflammatory factors were determined by enzyme-linked immunosorbent assay (ELISA). Blood cells were detected by automatic biochemical analyzer. The metabolite changes and gene expression levels, the potential targets and pathways of CPE in regulating immune function of thymus were analyzed by integrative analysis of transcriptomic and metabolomic methods., Results: High dose of CPE increased the thymus index and spleen index of septic rats at different stages, and the brain index at different stages could be increased at medium dose and high dose. Medium and high doses of CPE reduced the pathological changes of thymus, spleen and brain tissue. CPE promoted the expression levels of CD4 in the thymus and spleen. CPE improved the levels of red blood cells (RBC), lymphocytes (LYM) and hemoglobin (HGB), and decreased the levels of neutrophils (NEUT), NLR (NEUT/LYM) and PLR (PLT/LYM). CPE dynamically regulated the levels of white blood cells (WBC) and PLT (platelet). CPE dynamically regulated the expression levels of infectious factors, immune factors, and inflammatory factors related to disease severity., Conclusion: CPE has the ability to dynamically modulate the expression levels of infectious factors, immune factors, and inflammatory factors related to disease severity, and alleviate the damages of immune organs. The research has provided a global view of the integration of metabolomics and transcriptomics to elucidate the immunomodulatory effects and mechanisms of CPE. CPE could affect a series of biological processes in glycerophospholipid metabolism by interfering with the B cell receptor (BCR) signaling pathway in the thymus, to maintain immune homeostasis of septic rats on the whole, especially humoral immunity., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Oncolytic viruses (OVs) emerge as a promising cancer immunotherapy. However, the temporal impact on tumor cells and the tumor microenvironment, and the nature of anti-tumor immunity post-therapy remain largely unclear. Here we report that CD4 + T cells are required for durable tumor control in syngeneic murine models of glioblastoma multiforme after treatment with an oncolytic herpes simplex virus (oHSV) engineered to express IL-12. The upregulated MHCII on residual tumor cells facilitates programmed polyfunctional CD4 + T cells for tumor control and for recall responses. Mechanistically, the proper ratio of Bcl-6 to T-bet in CD4 + T cells navigates their enhanced anti-tumor capacity, and a reciprocal IL6ra-Bcl-6 regulatory axis in a memory CD4 + T-cell subset, which requires MHCII signals from reprogrammed tumor cells, tumor-infiltrating and resident myeloid cells, is necessary for the prolonged response. These findings uncover an OV-induced tumor/myeloid-CD4 + T-cell partnership, leading to long-term anti-tumor immune memory, and improved OV therapeutic efficacy., Competing Interests: Competing interests: J.M.M. received payments from the structured buyout of Catherex, Inc., which was purchased by Amgen in 2015 and no longer exists. J.M.M. also has equity in and has received royalties from Aettis, Inc., which holds frozen oncolytic viral stocks. J.M.M. is a co-owner of Treovir, Inc which holds a small business innovation research fund to execute a clinical trial of G207 in pediatric patients. J.M.M. has served as a consultant for Imugene. J.M.M. holds intellectual property for another oncolytic virus, C134, which has been licensed to Mustang Bio, Inc., but is blinded to the specifics of the relationship. The remaining authors declare no competing interests., (© 2025. The Author(s).)

Epstein-Barr virus (EBV)-related hemophagocytic lymphohistiocytosis (EBV-HLH) and infectious mononucleosis (IM) are characterized by fever, hepatomegaly, and splenomegaly, but HLH has a 50% lethality rate. Therefore, this study aimed to compare the laboratory findings in differentiating EBV-HLH children from IM children who have fever, hepatomegaly, or splenomegaly. A total of 131 IM patients and 29 EBV-HLH pediatric patients with fever, hepatomegaly, or splenomegaly were enrolled in our study. The clinical traits and laboratory findings were analyzed, and a predictive regression analysis was also performed. EBV-HLH patients had a lower set of diagnostic markers, which included fibrinogen (FIB), white blood cells (WBC), hemoglobin (Hb), and platelet (PLT), compared to IM patients. Triglyceride (TG) and ferritin were elevated obviously in EBV-HLH patients compared to IM patients. CD4 dim CD8 + T cells are highly activated T cells. EBV-HLH patients experienced a significant decrease in the absolute number and ratio of CD4 dim CD8 + T cells (CD4 dim CD8 + T#, CD4 dim CD8 + T%) compared to IM patients in our study. The AUC of CD4 dim CD8 + T # in the diagnosis of EBV-HLH was 0.920 with a sensitivity of 86.2% and a specificity of 90.1%. A logistic regression analysis was developed to improve sensitivity. The results revealed that lower levels of Hb, FIB, and CD4 dim CD8 + T cells were risk factors for EBV-HLH. The regression model for separating EBV-HLH from EBV-IM had an AUC of was 0.996 with a sensitivity of 100% and a specificity of 95.3%. The ratio and absolute number of CD4 dim CD8 + T cells were decreased in IM and EBV-HLH patients. EBV-HLH can be identified in IM patients with fever, hepatomegaly, or splenomegaly by detecting Hb, FIB, and the absolute number of CD4 dim CD8 + T cells., Competing Interests: Declarations. Ethics approval: The study was approved by the local ethics committee of Hunan Children’s Hospital (Code: HCHLL-2024–471). Conflict of interest: The authors declare no competing interests., (© 2025. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Autoimmune liver diseases (AILD) involve dysregulated CD4 T cell responses against liver self-antigens, but how these autoreactive T cells relate to liver tissue pathology remains unclear. Here we perform single-cell transcriptomic and T cell receptor analyses of circulating, self-antigen-specific CD4 T cells from patients with AILD and identify a subset of liver-autoreactive CD4 T cells with a distinct B-helper transcriptional profile characterized by PD-1, TIGIT and HLA-DR expression. These cells share clonal relationships with expanded intrahepatic T cells and exhibit transcriptional signatures overlapping with tissue-resident T cells in chronically inflamed environments. Using a mouse model, we demonstrate that, following antigen recognition in the liver, CD4 T cells acquire an exhausted phenotype, play a crucial role in liver damage, and are controlled by immune checkpoint pathways. Our findings thus suggest that circulating autoreactive CD4 T cells in AILD are imprinted by chronic antigen exposure to promote liver inflammation, thereby serving as a potential target for developing biomarkers and therapies for AILD., Competing Interests: Competing interests: The authors declare no competing interest., (© 2025. The Author(s).)

We developed viral sensor and restriction factor-cytometry by time of flight (VISOR-CyTOF), which profiles 19 viral sensors and restriction factors (VISORs) simultaneously in single cells, and applied it to 41 postmortem tissues from people with HIV. Mucosal myeloid cells are well equipped with SAMHD1 and sensors of viral capsid and DNA while CD4 + T cells are not. In lymph node CD4 + Tfh, VISOR expression patterns reflect those favoring integration but blocking HIV gene expression, thus favoring viral latency. We also identify small subsets of bone marrow-, lung-, and gut-associated CD4 + T and myeloid cells expressing high levels of restriction factors targeting most stages of the HIV replication cycle. In vitro, HIV preferentially fuses to CD4 + T cells with a permissive VISOR profile, but early induction of select VISORs by T1IFN prevents productive HIV infection. Our findings document the diverse patterns of VISOR profiles across tissues and cellular subsets and define their association with susceptibility to HIV., Competing Interests: Declaration of interests The authors declare no completing interests., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Tumor-draining lymph node dendritic cells (DCs) are poor stimulators of tumor antigen-specific CD4 T cells; however, the mechanism behind this defect is unclear. We now show that, in tumor-draining lymph node DCs, a large proportion of major histocompatibility complex class II (MHC-II) molecules retains the class II-associated invariant chain peptide (CLIP) fragment of the invariant chain bound to the MHC-II peptide binding groove due to reduced expression of the peptide editor H2-M and enhanced activity of the CLIP-generating proteinase cathepsin S. The net effect of this is that MHC-II molecules are unable to efficiently bind antigenic peptides. DCs in mice expressing a mutation in the invariant chain sequence that results in enhanced MHC-II-CLIP accumulation are poor stimulators of CD4 T cells and have diminished anti-tumor responses. Our data reveal a previously unknown mechanism of immune evasion in which enhanced expression of MHC-II-CLIP complexes on tumor-draining lymph node DCs limits MHC-II availability for tumor peptides., Competing Interests: Declaration of interests The authors declare no competing interests., (Published by Elsevier Inc.)

Objective: Global per capita alcohol consumption is increasing, posing significant socioeconomic and medical challenges also due to alcohol-related traumatic injuries but also its biological effects. Trauma as a leading cause of death in young adults, is often associated with an increased risk of complications, such as sepsis and multiple organ failure, due to immunological imbalances. Regulatory T cells play a crucial role in maintaining immune homeostasis by regulating the inflammatory response. Since it is crucial to understand the effects of alcohol in healthy volunteers, in order to refer findings from trauma cohorts, this study investigates the time- and dose-dependent modulation of CD4 + lymphocytes and their subsets following acute alcohol consumption, considering both general and sex-specific variations., Methods: Twelve female and ten male healthy volunteers consumed twelve alcohol mixed drinks over four hours to achieve a blood alcohol level of 1.0‰. Blood samples were collected before and at various time points (2, 4, 6, 24 and 48 h) post-consumption for flow cytometric analyses of the phenotype and activation makers CD4/CD25/CD127 of CD4 + T cells and their subtypes., Results: CD4 + lymphocytes significantly decreased at 4 h and increased at 6 h post-alcohol consumption. Naïve CD25 - CD127 + T cells significantly decreased from 2 to 24 h in women and 2 to 48 h in men, while CD25 + CD127 + effector T cells significantly increased during the same period. Natural CD25 + CD127 - regulatory T cells increased significantly at 4 and 6 h, with a higher increase in men. Induced regulatory T cells (CD4 + CD25 high CD127 - ) significantly increased at 2 h for all volunteers, with lower proportions of natural and induced regulatory T cells in women., Conclusions: Acute alcohol consumption induces immune modulation persisting for days, impacting T cell subsets differently in men and women. The prolonged modulation in men may contribute to slightly poorer clinical outcomes, emphasizing the need to consider these effects in trauma patients with acute alcohol intoxication., Competing Interests: Declarations. Ethics approval and consent to participate: This study was performed at the University Hospital of the Goethe-University Frankfurt with institutional ethics committee approval (255/14), in accordance with the Declaration of Helsinki and following the Strengthening the Reporting of Observational studies in Epidemiology (STROBE)-guideline. All healthy volunteers signed the written informed consent form in accordance with ethical standards after detailed explanation of the procedure, effects and objectives of the investigation. Competing interests: The authors declare no competing interests., (© 2025. The Author(s).)

Background: Malignant clones of primary cutaneous T-cell lymphomas (CTCL) can show a CD4+, CD8+ or T-cell receptor (TCR)-γδ+ phenotype, but their individual impact on tumour biology and skin lesion formation remains ill defined., Objectives: To perform a comprehensive molecular characterization of CD4+ vs. CD8+ and TCR-γδ+ CTCL lesions., Methods: We performed single-cell RNA sequencing (scRNAseq) of 18 CTCL skin biopsies to compare classic CD4+ advanced-stage mycosis fungoides (MF) with TCR-γ/δ+ MF and primary cutaneous CD8+ aggressive epidermotropic cytotoxic T-cell lymphoma (Berti lymphoma)., Results: Malignant clones of TCR-γ/δ+ MF and Bertilymphoma showed similar clustering patterns distinct from CD4+ MF, along with increased expression of cytotoxic markers such as NKG7, CTSW, GZMA and GZMM. Only advanced-stage CD4+ MF clones expressed central memory T-cell markers (SELL, CCR7, LEF1), alongside B1/B2 blood involvement, whereas TCR-γδ+ MF and Berti lymphoma harboured a more tissue-resident phenotype (CD69, CXCR4, NR4A1) without detectable cells in the blood. CD4+ MF and TCR-γδ+ MF skin lesions harboured strong type 2 immune activation across myeloid cells, while Berti lymphoma was more skewed toward type 1 immune responses. Both CD4+ MF and TCR-γδ+ MF lesions showed upregulation of keratinocyte hyperactivation markers such as S100A genes and KRT16. This increase was entirely absent in Berti lymphoma, possibly reflecting an aberrant keratinocyte response to invading tumour cells, which could contribute to the formation of the typical ulceronecrotic lesions within this entity., Conclusions: Our scRNAseq profiling study reveals specific molecular patterns associated with distinct CTCL subtypes., Competing Interests: Conflicts of interest: W.W. has received personal fees from LEO Pharma, Pfizer, Sanofi Genzyme, Eli Lilly, Novartis, Boehringer Ingelheim, AbbVie and Janssen. J.G. has received personal fees from AbbVie, Eli Lilly, Pfizer, Boehringer Ingelheim and Novartis. C.J. has received personal fees from LEO Pharma, UCB Pharma, Pfizer, Recordati Rare Diseases, Eli Lilly, Novartis, Takeda, Kyowa Kirin, Boehringer Ingelheim, Bristol Myers Squibb, AbbVie, Janssen and Almirall. C.J. is an investigator for Eli Lilly, Novartis, Innate Pharma, AbbVie, Incyte, Boehringer Ingelheim and Almirall. P.M.B. has received personal fees from Almirall, Sanofi, Janssen, LEO Pharma, AbbVie, Pfizer, Boehringer Ingelheim, GSK, Regeneron, Eli Lilly, Celgene, Novartis, UCB, Merck, Galderma and BMS. P.M.B. is an investigator for Pfizer and Abbvie. P.M.B has also received research support from Pfizer (grant paid to his institution). The other authors declare no conflicts of interest., (© The Author(s) 2024. Published by Oxford University Press on behalf of British Association of Dermatologists.)

Autoimmune uveitis (AU) is a sight-threatening ocular autoimmune disorder that often manifests as retinal vasculitis. Increased neutrophil infiltration around retinal vessels has been reported during the progression of AU, while how they function is not fully recognized. Neutrophil extracellular traps (NETs), produced by activated neutrophils, have been suggested to be detrimental in autoimmune diseases. Here, we found that NETs were elevated in patients with active AU, and this was verified in an experimental AU (EAU) mouse model. Depletion of neutrophils or degradation of NETs with deoxyribonuclease-I (DNase I) could decrease CD4+ effector T cell (Teff) infiltration in retina and spleen to alleviate EAU. Moreover, we found that the expression of adhesion molecules, selectin, and antigen-presenting molecules was elevated in EAU retina and in retinal microvascular endothelial cells (RMECs) cocultured with NETs. The stimulated RMECs further facilitated CD4+ T cell adhesion, activation, and differentiation into Teffs. Mechanistically, NETs trigger RMEC activation by hastening cell senescence through the cyclic GMP-AMP synthase (cGAS)/stimulator of interferon genes (STING) pathway. Slowing down senescence or inhibiting the cGAS/STING pathway in RMECs reduces the activation and differentiation of CD4+ T cells. These results suggest a deleterious role of NETs in AU. Targeting NETs would offer an effective therapeutic method.

T cells targeting a KRAS mutation can induce durable tumor regression in some patients with metastatic epithelial cancer. It is unknown whether T cells targeting mutant KRAS that are capable of killing tumor cells can be identified from peripheral blood of patients with pancreatic cancer. We developed an in vitro stimulation approach and identified HLA-A*11:01-restricted KRAS G12V-reactive CD8+ T cells and HLA-DRB1*15:01-restricted KRAS G12V-reactive CD4+ T cells from peripheral blood of 2 out of 6 HLA-A*11:01-positive patients with pancreatic cancer whose tumors expressed KRAS G12V. The HLA-A*11:01-restricted KRAS G12V-reactive T cell receptor (TCR) was isolated and validated to specifically recognize the KRAS G12V8-16 neoepitope. While T cells engineered to express this TCR specifically recognized all 5 tested human HLA-A*11:01+ and KRAS G12V+ pancreatic cancer organoids, the recognition was often modest, and tumor cell killing was observed in only 2 out of 5 organoids. IFN-γ priming of the organoids enhanced the recognition and killing by the TCR-engineered T cells. The TCR-engineered T cells could significantly slow the growth of an established organoid-derived xenograft in immunodeficient mice. Our data suggest that this TCR has potential for use in TCR-gene therapy, but additional strategies that enhance tumor recognition by the TCR-engineered T cells likely will be required to increase clinical activity.

Fungal spores are abundant in the environment and a major cause of asthma. Originally characterised as a type 2 inflammatory disease, allergic airway inflammation that underpins asthma can also involve type 17 inflammation, which can exacerbate disease causing failure of treatments tailored to inhibit type 2 factors. However, the mechanisms that determine the host response to fungi, which can trigger both type 2 and type 17 inflammation in allergic airway disease, remain unclear. Here we find that CD11c + DCs and CD4 + T cells are essential for development of both type 2 and type 17 airway inflammation in mice repeatedly exposed to inhaled spores. Single cell RNA-sequencing with further multi-parameter cytometry shows that allergic inflammation dramatically alters the proportion of numerous DC clusters in the lung, but that only two of these (Mgl2 + cDC2s and CCR7 + DCs) migrate to the dLNs. Targeted removal of several DC subsets shows that Mgl2 + cDC2 depletion reduces type 2, but not type 17, fungal allergic airway inflammation. These data highlight distinct DC subsets as potential therapeutic targets for the treatment of pulmonary fungal disease., Competing Interests: Competing interests: Individuals based at the Lydia Becker Institute received funding from GSK. These authors (P.C.C., S.L.B, E.L.H., F.R.S., A.S.M.) declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. The remaining authors declare no competing interests., (© 2025. The Author(s).)

Interleukin 6 (IL-6), produced by immune cells, is crucial in promoting T cell trafficking to infection and inflammation sites, influencing various physiological and pathological processes. Concentrations of IL-6 and other cytokines and chemokines can influence T cell differentiation and activation. Understanding the dual faces of IL-6 within the tumor microenvironment is crucial to understanding its role. A flow-based microsystem was designed to investigate CD4 + T cell activation in response to different IL-6 gradients in an under-control 3D culture. The study found that cancer cells' response to varying IL-6 concentrations was dynamic and dose-sensitive, with immune cell migration rates showing sensitivity to the IL-6 gradient. A549 cell expansion increases gradually and time-dependently with 50 ng of IL-6, while Jurkat cell migration follows a time-dependent pattern. However, when a total of 100 ng IL-6 concentration is applied, A549 cells expand rapidly, potentially influencing Jurkat cell migration. Jurkat cell mobility is lower, possibly due to increased A549 cell presence and heightened cell-cell interactions. Different IL-6 concentration gradients can modulate the expression of some CD markers like CD69 and programed cell death protein 1 in CD4 + T cells, suggesting that IL-6 concentration gradients affect immune cell phenotypes. This suggests that IL-6 plays a crucial role in activating T helper cells and may be involved in the later phases of inflammation. Also, the increased levels of IFN-γ and TNF-α highlight IL-6's impact on T cell inflammatory response. This study emphasizes the intricate effects of IL-6 on T cell activation, phenotype, cytokine production, and phenotypic heterogeneity, providing valuable insights into immune response modulation in an experimental setting.

High-efficacy antiretroviral treatment (ART) has been a game-changer for HIV/AIDS pandemic, but incomplete CD4 + T cell recovery and persistent chronic immune activation still affect HIV-suppressed people. Exceptional cases of HIV infection that naturally exhibit delayed disease progression provide invaluable insights into protective biological mechanisms with potential clinical application. Viremic non-progressors (VNPs) represent an extremely rare population of individuals with HIV, characterized by preservation of the CD4 + T cell compartment despite persistent high levels of viral load (>10,000 copies/mL). While only a few studies have investigated the immunovirological characteristics of adult and pediatric VNPs, most of our knowledge about this phenotype stems from its non-human-primate counterpart, the natural simian immunodeficiency virus (SIV) hosts. In this review, we synthesize the insights gained from recent studies of natural SIV hosts and VNPs and evaluate the potential similarities and differences in the mechanisms that underlie the absence of pathogenesis, with special focus on the control of immune activation., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Background and Aim: Ulcerative colitis (UC) is characterized by complex immunological interactions involving CD4 T cell subsets and the NLRP3 inflammasome, which influence inflammatory responses. This investigation focused on delineating the activation profiles of these components and their correlation with disease severity and activity, assessing their diagnostic implications in UC., Methods: We conducted immunohistochemistry and ELISA assays to measure markers expression of CD4 T cell subsets and the NLRP3 inflammasome in UC patients versus controls. Findings were validated using correlation analysis, molecular docking and ROC curves., Results: UC patients displayed increased Th1 (T-bet, TNF-α), Th2 (GATA3, IL-6), and Th17 (RORγt, IL-17, IL-22, IL-23) markers versus controls. Additionally, Th1 and Th2 cytokines (IL-2 and IL-4) were significantly elevated in severe UC, while Treg markers (FOXP3, IL-10, TGF-β1) were elevated only in mild-to-moderate UC. Enhanced NLRP3 inflammasome activation, indicated by elevated NLRP3, Caspase-1, and IL-1β levels. These molecular patterns, confirmed through correlation analysis and molecular docking, underscored strong correlations among NLRP3, T-bet, and GATA3, supporting the proposed NLRP3/T-bet/GATA3 axis. This axis, along with other biomarkers, showed strong associations with UC severity, Mayo score, UCEIS, demonstrated relatively high diagnostic value., Conclusion: The NLRP3/T-bet/GATA3 axis provides a referable strategy for multi-targeted combined treatment of UC and may serve as potential biomarkers for enhancing diagnostic accuracy and guiding therapy., Competing Interests: Declarations. Ethics approval and consent to participate: The study was conducted in accordance with the Declaration of Helsinki and approved by the Ethics Committee of the Second Affiliated Hospital of Zhejiang Chinese Medical University, which was registered in the National Universal Health Coverage Information Platform for Medical Research Registration and Grading System under registration number MR-33–24-015054. The Ethics Committee endorsed the study protocol, which was determined to not require informed consent from participants. All participant information remained confidential throughout the duration of the study. Consent for publication: Not applicable. Competing interests: The authors declare no competing interests., (© 2025. The Author(s).)

Growing evidence suggests that systemic immune and inflammatory responses may play a critical role in the formation and development of aneurysms. Exploring the differences between single intracranial aneurysm (SIA) and multiple IAs (MIAs) could provide insights for targeted therapies. However, there is a lack of comprehensive and detailed characterization of changes in circulating immune cells in MIAs. Peripheral blood mononuclear cell (PBMC) samples from patients with SIA (n = 16) or MIAs (n = 6) were analyzed using high-dimensional mass cytometry to evaluate the frequency and phenotype of immune cell subtypes. A total of 25 cell clusters were identified, revealing that the immune signature of MIAs included cluster changes. Compared to patients with SIA, patients with MIAs exhibited immune dysfunction and regulatory imbalance in T-cell clusters. They also had reduced numbers of CD8+ T cells and their subgroups CD8+ Te and CD8+ Tem cells, as well as reduced numbers of the CD4+ T-cell subgroup CD27-CD4+ Tem cells. Furthermore, compared to SIA, MIAs were associated with enhanced T-cell immune activation, with elevated expression levels of CD3, CD25, CD27, CCR7, GP130, and interleukin 10. This study provides insights into the circulating immune cell profiles in patients with MIAs, highlighting the similarities and differences between patients with SIA and those with MIAs. Furthermore, the study suggests that circulating immune dysfunction may contribute to the development of MIAs., (© The Author(s) 2024. Published by Oxford University Press on behalf of the British Society for Immunology. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Rheumatoid arthritis (RA) is associated with high-risk HLA class II alleles known as the "RA shared epitope." Among prevalent shared epitope alleles, study of DRB1*04:04 has been limited. To define relevant epitopes, we identified citrullinated peptide sequences from synovial antigens that were predicted to bind to HLA-DRB1*04:04 and utilized a systematic approach to confirm their binding and assess their recognition by CD4 T cells. After confirming the immunogenicity of 13 peptides derived from aggrecan, cartilage intermediate layer protein (CILP), α-enolase, vimentin, and fibrinogen, we assessed their recognition by T cells from a synovial tissue sample, observing measurable responses to 8 of the 13 peptides. We then implemented a multicolor tetramer panel to evaluate the frequency and phenotype of antigen-specific CD4 T cells in individuals with anti-citrullinated protein antibody-positive RA and controls. In subjects with RA, CILP-specific T-cell frequencies were significantly higher than those of other antigens. The surface phenotypes exhibited by antigen-specific T cells were heterogeneous, but Th1-like and Th2-like cells predominated. Stratifying based on disease status and activity, antigen-specific T cells were more frequent and most strongly polarized in RA subjects with high disease activity. In total, these findings identify novel citrullinated epitopes that can be used to interrogate antigen-specific CD4 T cells and show that antigen-specific T-cell frequency is elevated in subjects with high disease activity., (© The Author(s) 2024. Published by Oxford University Press on behalf of the British Society for Immunology. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

T cells are one of the main drivers of inflammatory bowel diseases (IBD). Infliximab (IFX) is used in the treatment of IBD as an anti-inflammatory drug to induce remission by neutralizing TNFα. We determined the individual chemokine/homing receptor and cytokine profile in pediatric IBD patients before and during IFX therapy to identify predictive biomarkers for therapy success. Peripheral blood CD4+ cells from pediatric patients with IBD were immunomagnetically isolated and either directly analyzed by FACS for cell distribution and chemokine/homing receptor expression or evaluated for cytokine production after in-vitro-stimulation. Twenty-one responders (RS) and 21 non-responders (NRS) were recruited. Before IFX therapy, flow cytometry revealed decreased percentages of naïve conventional T cells in pediatric IBD patients. The proportions of CD62-L+ T cells were decreased in both CD and UC therapy responders. The cytokine profile of T cells was highly altered in IBD patients compared to healthy controls (HC). During IFX therapy, the frequencies of conventional memory and regulatory memory T cells expanded in both cohorts. IFX response was marked by a decrease of α4β7+ and IFNγ+ memory T cells in both CD and UC. In contrast, frequencies of Lag-3+ T cells proved to be significantly increased in NRS. These observations were irrespective of the underlying disease. T cells of pediatric IBD patients display an activated and rather Th1/Th17-shifted phenotype. The increased expression of the checkpoint molecule Lag-3 on T cells of NRS resembles a more exhausted phenotype than in RS and HC which appeared to be a relevant predictive marker for therapy failure., (© The Author(s) 2024. Published by Oxford University Press on behalf of the British Society for Immunology. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Introduction: Multiple sclerosis (MS) is a chronic immune-mediated demyelinating disease of the central nervous system, whereby clinical disease activity is primarily monitored by magnetic resonance imaging., Methods: Given the limitations associated with implementing and acquiring novel and emerging imaging biomarkers in routine clinical practice, the discovery of biofluid biomarkers may offer a more simple and cost-effective measure that would improve accessibility, standardization, and patient care. Extracellular vesicles (EVs) are nanoparticles secreted from cells under both homeostatic and pathological states, and have been recently investigated as biomarkers in MS. The objectives of this study were to longitudinally measure levels of specific immune cell-derived EVs in MS and provide evidence that EV sub-populations may serve as biomarkers of disease activity, axonal injury, and/or clinical disability., Results: Our results demonstrate that the rate of clinical disability in MS negatively correlates with changes in circulating CD3+ EVs within the plasma. Additionally, numbers of CD4+ EVs decrease in individuals with increasing pNfL levels overtime whereby the magnitude of the pNfL increase negatively correlates with changes in plasma CD4+ and CD8+ EVs. Finally, when applying NEDA-3 criteria to define active versus stable disease, individuals with active disease had significantly elevated CD4+ and CD8+ EVs compared to stable disease., Conclusion: In summary, the analysis of specific immune cell-derived EV subsets may provide a method to monitor disability accumulation, disease activity, and axonal injury in MS, while also providing insights into the pathophysiology and cellular/molecular mechanisms that influence progression., (© The Author(s) 2025. Published by Oxford University Press on behalf of the British Society for Immunology.)

Haploinsufficiency of the transcription factor interferon-regulatory factor 4 (IRF4) prevents the onset of spontaneous diabetes in NOD mice. However, the immunological mechanisms of the IRF4-mediated disease regulation remain unclear. This study aims to investigate the role of IRF4 in the pathogenesis of autoimmune diabetes by conducting adoptive transfer experiments using donor IRF4 gene-deficient CD4+ T cells from BDC2.5-transgenic (Tg) NOD mice and recipient Rag1-knockout NOD mice, respectively. Through this approach, we analyzed both clinical and immunological phenotypes of the recipient mice. Additionally, IRF4-deficient BDC2.5 CD4+ T cells were stimulated to assess their immunological and metabolic phenotypes in vitro. The findings revealed that diabetes was completely prevented in the recipients with Irf4-/- T cells and was approximately 50% lower in those with Irf4+/- T cells than in wild type (WT) controls, whereas Irf4-/- recipients with WT T cells only showed a delayed onset of diabetes. Islet-infiltrating T cells isolated from recipients with Irf4+/- T cells exhibited significantly lower proliferation and IFN-γ/IL-17 double-positive cell fraction rates compared with those in WT controls. Irf4-/- BDC2.5 CD4+ T cells stimulated in vitro showed a reduced number of cell divisions, decreased antigen-specific T-cell markers, and impairment of glycolytic capacity compared with those observed in WT controls. We concluded that IRF4 predominantly regulates the diabetogenic potential in a dose-dependent manner by mediating the proliferation and differentiation of islet-infiltrating T cells while playing an adjunctive role in the innate immune responses toward diabetes progression in NOD mice., (© The Author(s) 2024. Published by Oxford University Press on behalf of the British Society for Immunology. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)