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International audience; Cardiac surgery with cardiopulmonary bypass (CPB) is associated with an immune paresis that predisposes to the development of postoperative infections and sepsis. Among factors responsible for CPB-induced immunosuppression, circulating myeloid-derived suppressor cells (MDSCs) have been found to induce early lymphocyte apoptosis and lymphocyte proliferation inhibition. However, the mechanisms involved are not fully understood. In this study, we found that the main lymphocyte subsets decreased significantly 24 h after cardiac surgery with CBP. As expected, cardiac surgery with CPB induced a monocytic MDSC expansion associated with an increased T-cell apoptosis and decreased proliferation capacity. Noteworthy, granulocytic MDSCs remain stable. Myeloid-derived suppressor cell depletion restored the ability of T-cell to proliferate ex vivo. After CPB, indoleamine 2,3-dioxygenase activity and IL-10 plasma level were increased such as programmed death-ligand 1 monocytic expression, whereas plasma level of arginine significantly decreased. Neither the inhibition of indoleamine 2,3-dioxygenase activity nor the use of anti-programmed death-ligand 1 or anti-IL-10 blocking antibody restored the ability of T-cell to proliferate ex vivo. Only arginine supplementation restored partially the ability of T-cell to proliferate.

To assess whether probiotic supplementation may reduce disease-linked systemic immune activation in people living with HIV with the immunologic nonresponder phenotype.Phase 2b, randomized, double-blind, placebo-controlled pilot trial.HIV-positive individuals with blood CD4+ T-cell counts350/mm3 despite viral suppression were randomized to 2:1 to receive De Simone Formulation Probiotic (DSFP; "Visbiome" commercially) or placebo for 48 weeks; target enrollment was 36 patients. The primary endpoint was the change in blood CD8+ T-cell coexpression of human leukocyte antigen-DR isotype and CD38 ("CD8 activation"). Secondary endpoints included biomarkers of inflammation, immune reconstitution, bacterial translocation, and gut permeability. Adjusted linear regression and linear mixed regression methods evaluated the differences between study arms from baseline to week 48. Study monitoring was performed by the CIHR Canadian HIV Trials Network Data Safety Monitoring Committee.Nineteen patients received DSFP, whereas 10 received placebo. One probiotic arm patient withdrew early. Blood CD8 activation increased 0.82 percentage points (pp) in the probiotic arm (95% confidence interval: -1.23 to 2.87;) and decreased by 2.06 pp in the placebo arm (-4.81 to 0.70; between arms P = 0.097). CD4+ T-cell activation (%HLA-DR+) decreased in the placebo arm [-3.79 pp (-7.32 to -0.26)] but increased in the probiotic arm [1.64 (-0.98 to 4.26); between arms P = 0.018]. No differences were observed in plasma or urine biomarkers of inflammation or microbial translocation.Blood immune activation markers in immunologic nonresponder individuals on effective antiretroviral treatment were not reduced by supplementation with DSFP; CD4+ T-cell activation may have been increased.

BACKGROUND & AIMS CD8 T cells are essential in controlling Hepatitis B virus (HBV) infection. Viral control is dependent on efficient recognition of HBV-infected hepatocytes by CD8 T cells, which can induce direct lysis of infected hepatocytes. In addition, CD8 T cells produce IFN-γ, which mediates non-cytopathic viral clearance. Innate immunomodulators and HBV-targeted RNA interference (RNAi) are being developed to treat chronic hepatitis B, but may modify HBV antigen presentation and impact CD8 T cell recognition, in addition to their primary mechanisms of action. APPROACH & RESULTS HBV infected HepG2-NTCP were treated with tenofovir disoproxil fumarate (TDF), Toll-like receptor (TLR) 7/8 agonists, TLR7/8 conditioned media (CM) collected from immune cells, or RNAi using short-interfering RNAs (siRNAs). The effect of these treatments on antigen presentation was measured through co-culture with CD8 T cells recognizing HLA-A0201 restricted epitopes, HBc18-27 or HBs183-191. Cytokine profiles of TLR7/8 CM was measured using cytometric bead array. TDF reduced viral replication, but not CD8 T cell recognition of infected cells. Direct exposure of infected HepG2-NTCP to TLR7/8 agonists had no impact on T cell recognition. Exposure of infected HepG2-NTCP to TLR7/8 CM enhanced HBV-specific CD8 T cell recognition through type 1 interferon (IFN) and IFN-γ dependent mechanisms. RNAi rapidly suppressed HBV DNA, HBV Core antigen (HBcAg), and HBV S antigen (HBsAg) expression, impairing recognition by HBV-specific CD8 T cells. CONCLUSIONS Immunomodulation, and RNAi, but not nucleos(t)ide analogues, alter recognition of infected HepG2-NTCP by HBV-specific CD8 T cells. Understanding these changes will inform combination treatments for CHB.

OBJECTIVE: A higher proportion of circulating memory CD4(+) T cells is associated with prevalent diabetes mellitus in persons with HIV (PWH) and HIV-negative persons. We assessed whether circulating T cell subsets could also identify individuals who will subsequently develop diabetes. DESIGN: This is a longitudinal follow-up study of PWH and similar HIV-negative individuals from the Veterans Aging Cohort Study who provided peripheral mononuclear blood cells between 2005 and 2007. METHODS: We quantified T cell subsets using flow cytometry and functional assays to identify CD4(+) and CD8(+) naïve, activated, senescent, memory (central, effector, and effector RA(+)), and T(H)1, T(H)2, and T(H)17-phenotype cells. The occurrence of an incident diabetes diagnosis (i.e., after baseline blood draw) was adjudicated by a two-physician chart review. Cox proportional hazards models adjusted for traditional risk factors, cytomegalovirus serostatus, and plasma inflammatory biomarkers assessed the relationship between T cell subsets and incident diabetes. RESULTS: 1837 participants (1259 PWH) without diabetes at baseline were included; 69% were black, 95% were male, and median follow-up was 8.6 years. Higher baseline frequencies of CD4(+) T effector memory RA(+) (T(EMRA)) cells defined as CD45RA(+) CD27(−) (p=0.04) and senescent T cells defined as CD4(+) CD28(−) (p=0.04) were associated with incident diabetes in PWH only. CONCLUSIONS: Higher frequencies of CD4(+) T(EMRA) and CD4(+) CD28(−) T cells were associated with incident diabetes in PWH only after adjustment for other factors. Additional studies are necessary to assess whether these cells act in blood via inflammatory mediators or reflect T cell populations in metabolically active tissues.

Objective: Patients with end-stage renal disease depend on hemodialysis for survival. Although arteriovenous fistulae (AVF) are the preferred vascular access for hemodialysis, the primary success rate of AVF is only 30% to 50% within 6 months, showing an urgent need for improvement. PD-L1 (programmed death ligand 1) is a ligand that regulates T-cell activity. Since T cells have an important role during AVF maturation, we hypothesized that PD-L1 regulates T cells to control venous remodeling that occurs during AVF maturation. Approach and results: In the mouse aortocaval fistula model, anti-PD-L1 antibody (200 mg, 3×/wk intraperitoneal) was given to inhibit PD-L1 activity during AVF maturation. Inhibition of PD-L1 increased T-helper type 1 cells and T-helper type 2 cells but reduced regulatory T cells to increase M1-type macrophages and reduce M2-type macrophages; these changes were associated with reduced vascular wall thickening and reduced AVF patency. Inhibition of PD-L1 also inhibited smooth muscle cell proliferation and increased endothelial dysfunction. The effects of anti-PD-L1 antibody on adaptive venous remodeling were diminished in nude mice; however, they were restored after T-cell transfer into nude mice, indicating the effects of anti-PD-L1 antibody on venous remodeling were dependent on T cells. Conclusions: Regulation of PD-L1 activity may be a potential therapeutic target for clinical translation to improve AVF maturation.

BACKGROUND BK nephropathy (BKN) in kidney transplants diagnosed by histology is challenging because it involves damage from both virus activity and cognate T cell-mediated inflammation, directed against alloantigens (rejection) or viral antigens. The present study of indication biopsies from the Integrated Diagnostic System in the International Collaborative Microarray Study Extension study measured major capsid viral protein 2 (VP2) mRNA to assess virus activity and a T cell-mediated rejection (TCMR) classifier to assess cognate T cell-mediated inflammation. METHODS Biopsies were assessed by local standard-of-care histology and by genome-wide microarrays and Molecular Microscope Diagnostic System (MMDx) algorithms to detect rejection and injury. In a subset of 102 biopsies (50 BKN and 52 BKN-negative biopsies with various abnormalities), we measured VP2 transcripts by real-time polymerase chain reaction. RESULTS BKN was diagnosed in 55 of 1679 biopsies; 30 had cognate T cell-mediated activity assessed by by MMDx and TCMR lesions, but only 3 of 30 were histologically diagnosed as TCMR. We developed a BKN probability classifier that predicted histologic BKN (area under the curve = 0.82). Virus activity (VP2 expression) was highly selective for BKN (area under the curve = 0.94) and correlated with acute injury, atrophy-fibrosis, macrophage activation, and the BKN classifier, but not with the TCMR classifier. BKN with molecular TCMR had more tubulitis and inflammation than BKN without molecular TCMR. In 5 BKN cases with second biopsies, VP2 mRNA decreased in second biopsies, whereas in 4 of 5 TCMR classifiers, scores increased. Genes and pathways associated with BKN and VP2 mRNA were similar, reflecting injury, inflammation, and macrophage activation but none was selective for BKN. CONCLUSIONS Risk-benefit decisions in BKN may be assisted by quantitative assessment of the 2 major pathologic processes, virus activity and cognate T cell-mediated inflammation.

Cutaneous lymphoid hyperplasia (CLH) is a benign reactive process with T-cell or B-cell lymphocytic infiltration in the skin, which can simulate cutaneous lymphomas both clinically and histologically. Various antigenic stimuli have been implicated in the development of CLH, including tick bites. Finding histologic evidence of such triggering factors, however, is often difficult. Moreover, the presence of clonality in CLH can potentially be interpreted as a neoplastic process, posing a further diagnostic challenge to dermatopathologists, if one is not aware of such peculiar phenomena. Herein, we describe a case of CLH secondary to a tick bite, featuring both T-cell clonality and monotypic plasma cells with lambda light chain restriction; the diagnostic clue being tick parts, which became evident on assessment of deeper levels. To the best of our knowledge, this is the first reported case of a tick-associated clonal CLH with simultaneous detection of monoclonal T cells and monotypic lambda light chain restriction, mimicking primary cutaneous CD4+ small/medium T-cell lymphoproliferative disorder and Borrelia-associated primary cutaneous marginal zone B-cell lymphoma, respectively.

Background:. Hyperbaric oxygen treatment (HBOT) has been demonstrated to influence the keloid recurrence rate after surgery and to relieve keloid symptoms and other pathological processes in keloids. To explore the mechanism of the effect of HBOT on keloids, tumor immune gene expression and immune cell infiltration were studied in this work. Methods:. From February 2021 to April 2021, HBOT was carried out on keloid patients four times before surgery. Keloid tissue samples were collected and divided into an HBOT group (keloid with HBOT before surgery [HK] group, n = 6) and a non-HBOT group (K group, n = 6). Tumor gene expression was analyzed with an Oncomine Immune Response Research Assay kit. Data were mined with R package. The differentially expressed genes between the groups were compared. Hub genes between the groups were determined and verified with Quantitative Real-time PCR. Immune cell infiltration was analyzed based on CIBERSORT deconvolution algorithm analysis of gene expression and verified with immunohistochemistry (IHC). Results:. Inflammatory cell infiltration was reduced in the HK group. There were 178 upregulated genes and 217 downregulated genes. Ten hub genes were identified, including Integrin Subunit Alpha M (ITGAM), interleukin (IL)-4, IL-6, IL-2, Protein Tyrosine Phosphatase Receptor Type C (PTPRC), CD86, transforming growth factor (TGF), CD80, CTLA4, and IL-10. CD80, ITGAM, IL-4, and PTPRC with significantly downregulated expression were identified. IL-10 and IL-2 were upregulated in the HK group but without a significant difference. Infiltration differences of CD8 lymphocyte T cells, CD4 lymphocyte T-activated memory cells, and dendritic resting cells were identified with gene CIBERSORT deconvolution algorithm analysis. Infiltration levels of CD4 lymphocyte T cell in the HK group were significantly higher than those of the K group in IHC verification. Conclusion:. HBOT affected tumor gene expression and immune cell infiltration in keloids. CD4 lymphocyte T cell, especially activated memory CD4+T, might be the key regulatory immune cell, and its related gene expression needs further study.

Purpose of review Autoantibodies are hallmark findings in systemic sclerosis (SSc), often present prior to disease onset. Clinical diagnosis and prognosis of SSc have long relied on the antitopoisomerase - anticentromere - anti-RNA polymerase antibody trichotomy. However, many more autoantibodies found in SSc are being actively investigated for insights into triggering events, mechanisms of tolerance break, and connections to tissue damage. This review examines recent studies on SSc autoantibodies and the early events that lead to their development. Recent findings Recent work has elucidated potential connections between human cytomegalovirus infection, silicone breast implants, and malignancy to SSc autoantibody development. At the level of the dendritic cell:T cell interaction, where tolerance is broken, new studies identified shared motifs in the peptide-binding domains of SSc-associated human leukocyte antigen alleles. Immunological analysis of SSc patient B cells has uncovered several anomalies in the regulatory capacities of SSc naive and memory B cell populations. Expanding efforts to uncover new SSc autoantibodies revealed anti-CXCL4, anticollagen V, and other autoantibodies as potential players in disease pathogenesis. Summary Further research into the role of autoantibodies in SSc development may uncover new mechanism-guided therapeutic targets. In addition, a better understanding of autoantibody associations with SSc disease outcomes will improve clinical care.

Traumatic injuries, such as burn, are often complicated by ethanol intoxication at the time of injury. This leads to a myriad of complications and post-burn pathologies exacerbated by aberrant immune responses. Recent findings suggest that immune cell dysfunction in the gastrointestinal system is particularly important in deleterious outcomes associated with burn injuries. In particular, intoxication at the time of burn injury leads to compromised intestinal T cell responses, which can diminish intestinal immunity and promote bacterial translocation, allowing for increased secondary infections in the injured host and associated sequelae, such as multiple organ failure (MOF) and sepsis. Regulatory T cells (Treg) have been identified as important mediators of suppressing effector T cell function. Therefore, the goal of this study was to assess the effects of ethanol intoxication and burn injury on Treg populations in small intestinal immune organs. We also evaluated the suppressive capability of Tregs isolated from injured animals. Male C57BL/6 mice were gavaged with 2.9 g/kg ethanol before receiving a ∼12.5% total body surface area scald burn. One day after injury, we identified a significant increase in Tregs number in small intestine Peyer's patches (∼1.5x) and lamina propria (∼2x). Tregs producing cytokine IL-10 were also increased in both tissues. Finally, Tregs isolated from ethanol and burn injured mice were able to suppress proliferation of effector T cells to a greater degree than sham vehicle Tregs. This was accompanied by increased levels of IL-10 and decreased levels of pro-proliferative cytokine IL-2 in cultures containing ethanol + burn Tregs compared to sham Tregs. These findings suggest that Treg populations are increased in intestinal tissues one day following ethanol intoxication and burn injury. Tregs isolated from ethanol and burn injured animals also exhibit a greater suppression of effector T cell proliferation, which may contribute to altered T cell responses following injury.

PURPOSE OF REVIEW: To discuss the clinical experience of coronavirus disease 2019 (COVID-19) in hematopoietic cell transplant and chimeric antigen receptor T-cell therapy recipients over the past year and to identify key knowledge gaps for future research. RECENT FINDINGS: Immunocompromised individuals and those with chronic health conditions are especially susceptible to infections, which have had a disproportionate impact on health outcomes during the COVID-19 pandemic. Several studies have evaluated the clinical characteristics and outcomes of transplant and cellular therapy (TCT) recipients who developed COVID-19. Age, sex, comorbid conditions, and social determinants of health are important predictors of the risk of severe acute respiratory syndrome coronavirus 2 infection and of the eventual severity of the disease. Various treatment approaches have been investigated over the last year. The paradigm of management strategies continues to evolve as more experience is accumulated. SUMMARY: In this review, we summarize some important findings as they relate to the clinical characteristics of TCT recipients who develop COVID-19. We also discuss some treatment approaches that are currently recommended and opine on vaccination in this population.

Background and aims Hepatitis C virus (HCV) leads to a high rate of chronic infection and T cell dysfunction. Although it is well known that chronic antigenic stimulation is a driving force for impaired T cell functions, the precise mechanisms underlying immune activation-induced T cell dysfunctions during HCV infection remain elusive. Approach and results Here, we demonstrated that circulating CD4+ T cells from patients who are chronically HCV-infected exhibit an immune activation status, as evidenced by the overexpression of cell activation markers human leukocyte antigen-antigen D-related, glucose transporter 1, granzyme B, and the short-lived effector marker CD127- killer cell lectin-like receptor G1+ . In contrast, the expression of stem cell-like transcription factor T cell factor 1 and telomeric repeat-binding factor 2 (TRF2) are significantly reduced in CD4+ T cells from patients who are chronically HCV-infected compared with healthy participants (HP). Mechanistic studies revealed that CD4+ T cells from participants with HCV exhibit phosphoinositide 3-kinase/Akt/mammalian target of rapamycin signaling hyperactivation on T cell receptor stimulation, promoting proinflammatory effector cell differentiation, telomeric DNA damage, and cellular apoptosis. Inhibition of Akt signaling during T cell activation preserved the precursor memory cell population and prevented inflammatory effector cell expansion, DNA damage, and apoptotic death. Moreover, knockdown of TRF2 reduced HP T cell stemness and triggered telomeric DNA damage and cellular apoptosis, whereas overexpression of TRF2 in CD4 T cells prevented telomeric DNA damage. Conclusions These results suggest that modulation of immune activation through inhibiting Akt signaling and protecting telomeres through enhancing TRF2 expression may open therapeutic strategies to fine tune the adaptive immune responses in the setting of persistent immune activation and inflammation during chronic HCV infection.

Supplemental Digital Content is available in the text., Next-generation T-cell therapies will likely continue to utilize T-cell receptors (TCRs) and chimeric antigen receptors (CARs) because each receptor type has advantages. TCRs often possess exceptional properties even when tested unmodified from patients’ T cells. CARs are generally less sensitive, possibly because their ligand-binding domains are grafted from antibodies selected for binding affinity or avidity and not broadly optimized for a functional response. Because of the disconnect between binding and function among these receptor types, the ultimate potential of CARs optimized for sensitivity and selectivity is not clear. Here, we focus on a thoroughly studied immuno-oncology target, the HLA-A*02/HPV-E629–38 complex, and show that CARs can be optimized by a combination of high-throughput binding screens and low-throughput functional assays to have comparable activity to clinical TCRs in acute assays in vitro. These results provide a case study for the challenges and opportunities of optimizing high-performing CARs, especially in the context of targets utilized naturally by TCRs.

BACKGROUND Regulatory T cell (Treg) therapy is a promising approach to amelioration of allograft rejection and promotion of organ transplant tolerance. However, the fate of infused Treg, and how this relates to their therapeutic efficacy using different immunosuppressive regimens is poorly understood. Our aim was to analyze the tissue distribution, persistence, replicative activity and phenotypic stability of autologous, donor antigen alloreactive Treg (darTreg) in anti-thymocyte globulin (ATG)-lymphodepleted, heart-allografted cynomolgus monkeys. METHODS darTreg were expanded ex vivo from flow-sorted, circulating Treg using activated donor B cells and infused posttransplant into recipients of major histocompatibility complex-mismatched heart allografts. Fluorochrome-labeled darTreg were identified and characterized in peripheral blood, lymphoid, and nonlymphoid tissues and the graft by flow cytometric analysis. RESULTS darTreg selectively suppressed autologous T cell responses to donor antigens in vitro. However, following their adoptive transfer after transplantation, graft survival was not prolonged. Early (within 2 wk posttransplant; under ATG, tacrolimus, and anti-IL-6R) or delayed (6-8 wk posttransplant; under rapamycin) darTreg infusion resulted in a rapid decline in transferred darTreg in peripheral blood. Following their early or delayed infusion, labeled cells were evident in lymphoid and nonlymphoid organs and the graft at low percentages (

Activation of porcine endothelial cells (PECs) is the mechanistic centerpiece of xenograft rejection. This study sought to characterize the immuno-phenotype of human T cells in response to PECs and to explore the immuno-modulation of B7 and mammalian target of rapamycin blockade of T cells and/or PECs during xeno-responses.Rapid memory T-cell (TM) responses to PECs were assessed by an intracellular cytokine staining. T-cell proliferation to PEC with or without belatacept or rapamycin was evaluated by a mixed lymphocyte-endothelial cell reaction (MLER). Additionally, rapamycin-pretreated PECs were used in MLER. Cell phenotypes were analyzed by flow cytometry.Tumor necrosis factor-α/interferon-γ producers were detected in CD8+ cells stimulated by human endothelium but not PECs. MLER showed proliferation of CD4+ and CD8+ cells with predominantly memory subsets. Purified memory and naive cells proliferated following PEC stimulation with an increased frequency of TM in PEC-stimulated naive cells. Proliferating cells upregulated programmed cell death-1 (PD-1) and CD2 expression. Belatacept partially inhibited T-cell proliferation with reduced CD2 expression and frequency of the CD8+CD2highCD28- subset. Rapamycin dramatically inhibited PEC-induced T-cell proliferation, and rapamycin-preconditioned PECs failed to induce T-cell proliferation. PD-1 blockade did not restore T-cell proliferation to rapamycin-preconditioned PECs.Humans lack rapid TM-mediated responses to PECs but induce T-cell proliferative responses characterized largely as TM with increasing CD2 and PD-1 expression. B7-CD28 and mammalian target of rapamycin blockade of T cells exhibit dramatic inhibitory effects in altering xeno-proliferating cells. Rapamycin alters PEC xeno-immunogenicity leading to inhibition of xeno-specific T-cell proliferation independent of PD-1-PD ligand interaction.

In the context of an evolving understanding of early T-cell precursor (ETP) lymphoma and leukemia, we present a case of concurrent T-cell lymphoblastic lymphoma and ETP lymphoma in an adolescent female. To our knowledge, this represents the first reported case of both lymphoblastic lymphoma and ETP lymphoma as distinct and conjoined components of the same neoplasm. As an exception to current literature, our patient had a strictly lymphomatous ETP component with no leukemic manifestation. Her ETP component remained viable following induction, supporting ETP resistance to chemotherapy. The patient remains in remission 4 years postallogeneic matched sibling donor bone marrow transplant.

The most common pathological subtype of renal carcinoma is RCC, and its development is closely related to immune infiltration. In our study, we investigated the relationship between zinc finger protein 668 and the prognostic risk, clinical characteristics, overall survival and related pathways. We analyzed the association between ZNF668 and immune cell infiltration through the TIMER database. The results showed that the expression of ZNF668 in RCC was higher than that in normal tissues (P < 0.001). The high expression of ZNF668 is clinically relevant, such as tumor stage (P = 0.001) and TNM classification (T: P = 7.37 e-04; N: P = 0.008; M: P < 0.001). Survival analysis showed that patients with high ZNF668 expression had a significantly poor prognosis (P = 0.023). Univariate analysis showed a significant decrease in overall survival in RCC patients with high ZNF668 expression (P = 0.023). Immuno-cell infiltration showed a significant decrease in CD4+ T cell and dendritic cell infiltration in RCC patients with high expression of ZNF668. GO/KEGG analysis showed that multiple pathways were differentially enriched in the high expression pathway of ZNF668, such as complement activation, and estrogen signaling pathway. In conclusion, high ZNF668 expression is a predictor in RCC.

Primary cutaneous CD4+ small/medium T-cell lymphoproliferative disorder and primary cutaneous marginal zone B-cell lymphoma are 2 distinct entities with several overlapping features which can result in diagnostic uncertainty. Clinically, they both follow an indolent course and present with solitary or multiple papules or nodules. Histologically, they are characterized by polymorphous dermal infiltrates rich in mixed populations of B cells and T cells, often in similar proportions. The histological hallmark of primary cutaneous CD4+ small/medium T-cell lymphoproliferative disorder is the presence of follicular T-helper cells within the infiltrate and has historically been used as a marker for differentiating between the 2 conditions. However, there is now mounting evidence that follicular T-helper cells are also seen in primary cutaneous marginal zone B-cell lymphoma and nodal marginal zone lymphoma. The 2 cases presented herein caused diagnostic uncertainty because they displayed appreciable features of both conditions. We discuss the potential mechanisms behind these overlapping histopathological features and hypothesize a model that explores the idea of a collective organoid response to an antigenic stimulus.

BACKGROUND Transplant glomerulopathy (TG) is a pathological feature of chronic active antibody-mediated rejection (cAMR) and is associated with renal allograft failure. The specific role of B cells in the pathogenesis of TG is unclear. METHODS We used a minor mismatched rat kidney transplant model with B cell-deficient recipients, generated by clustered regularly interspaced short palindromic repeats/Cas9 technology, to investigate the impact of B-cell depletion on the pathogenesis of TG. We hypothesized that B-cell deficiency would prevent TG in the rat kidney transplant model of cAMR. Treatment groups included syngeneic, allogeneic, sensitized allogeneic, and B cell-deficient allogeneic transplant recipients. RESULTS B cell-deficient recipients demonstrated reduced TG lesions, decreased microvascular inflammation, reduced allograft infiltrating macrophages, and reduced interferon gamma transcripts within the allograft. Allograft transcript levels of interferon gamma, monocyte chemoattractant protein-1, and interleukin-1β correlated with numbers of intragraft macrophages. B cell-deficient recipients lacked circulating donor-specific antibodies and had an increased splenic regulatory T-cell population. CONCLUSIONS In this model of cAMR, B-cell depletion attenuated the development of TG with effects on T cell and innate immunity.

Background:. Endotoxin tolerance (ET) is a protective phenomenon in which pre-treatment with a tolerance dose of lipopolysaccharide (LPS) leads to dramatically elevated survival. Accumulating evidence has shown that peripheral T cells contribute to the induction of ET. However, what happens to T cell development in the thymus under ET conditions remains unclear. The purpose of this study was to analyze the alterations in thymocyte populations (double-positive [DP] and single-positive [SP] cells) under ET conditions. Methods:. Mice were intraperitoneally injected with LPS at a concentration of 5 mg/kg to establish an LPS tolerance model and were divided into two groups: a group examined 72 h after LPS injection (72-h group) and a group examined 8 days after LPS injection (8-day group). Injection of phosphate-buffered saline was used as a control (control group). Changes in thymus weight, cell counts, and morphology were detected in the three groups. Moreover, surface molecules such as CD4, CD8, CD44, CD69, and CD62L were analyzed using flow cytometry. Furthermore, proliferation, apoptosis, cytokine production, and extracellular signal-regulated kinase (ERK) pathway signaling were analyzed in thymocyte populations. The polymorphism and length of the T-cell receptor (TCR) β chain complementarity-determining region 3 (CDR3) were analyzed using capillary electrophoresis DNA laser scanning analysis (ABI 3730). Results:. Thymus weight and cell counts were decreased in the early stage but recovered by the late stage in a murine model of LPS-induced ET. Moreover, the proportions of DP cells (control: 72.130 ± 4.074, 72-h: 10.600 ± 3.517, 8-day: 84.770 ± 2.228), CD4+ SP cells (control: 15.770 ± 4.419, 72-h: 44.670 ± 3.089, 8-day: 6.367 ± 0.513), and CD8+ SP cells (control: 7.000 ± 1.916, 72-h: 34.030 ± 3.850, 8-day: 5.133 ± 0.647) were obviously different at different stages of ET. The polymorphism and length of TCR β chain CDR3 also changed obviously, indicating the occurrence of TCR rearrangement and thymocyte diversification. Further analysis showed that the expression of surface molecules, including CD44, CD69, and CD62L, on thymocyte populations (DP and SP cells) were changed to different degrees. Finally, the proliferation, apoptosis, cytokine production, and ERK pathway signaling of thymocyte populations were changed significantly. Conclusion:. These data reveal that alterations in thymocyte populations might contribute to the establishment of ET.

Exhaustion of T cells occurs in response to chronic exposure to self and foreign antigens. It limits T cell capacity to proliferate and produce cytokines, leading to an impaired ability to clear chronic infections or eradicate tumors. T cell exhaustion is associated with a specific transcriptional, epigenetic, and metabolic program and characteristic cell surface markers' expression. Recent studies have begun to elucidate the role of T cell exhaustion in transplant. Higher levels of exhausted T cells have been associated with better graft function in kidney transplant recipients. In contrast, reinvigorating exhausted T cells by immune checkpoint blockade therapies, while promoting tumor clearance, increases the risk of acute rejection. Lymphocyte depletion and high alloantigen load have been identified as major drivers of T cell exhaustion. This could account, at least in part, for the reduced rates of acute rejection in organ transplant recipients induced with thymoglobulin and for the pro-tolerogenic effects of a large organ such as the liver. Amongst the drugs that are widely-used for maintenance immunosuppression, calcineurin inhibitors have a contrasting inhibitory effect on exhaustion of T cells, while the influence of mTOR inhibitors is still unclear. Harnessing or encouraging the natural processes of exhaustion may provide a novel strategy to promote graft survival and transplantation tolerance. Supplemental Visual Abstract; http://links.lww.com/TP/C250.

Background There are no effective systemic therapies for chordoma. The recent successes of immunotherapeutic strategies in other cancers have resulted in a resurgence of interest in using immunotherapy in chordoma. These approaches rely on a functional interaction between the host's immune system and the expression of tumor peptides via the human leukocyte antigen (HLA) Class I antigen. It is not known whether chordoma cells express the HLA Class I antigen. Questions/purposes (1) Do chordoma tumors exhibit defects in HLA Class I antigen expression? (2) What is the pattern of lymphocyte infiltration in chordoma tumors? Methods Patients with chordoma treated at Massachusetts General Hospital between 1989 and 2009 were identified with permission from the institutional review board. Of the 75 patients who were identified, 24 human chordoma tumors were selected from 24 distinct patients based on tissue availability. Histology slides from these 24 formalin-fixed paraffin-embedded chordoma tissue samples were deparaffinized using xylene and ethanol and underwent heat-induced antigen retrieval in a citrate buffer. Samples were incubated with monoclonal antibodies directed against HLA Class I antigen processing machinery components. Antibody binding was detected via immunohistochemical staining. Staining intensity (negative, weakly positive, strongly positive) was assessed semiquantitatively and the percentage of chordoma cells stained for HLA Class I antigen subunits was assessed quantitatively. Hematoxylin and eosin-stained histology slides from the same 24 chordoma samples were assessed qualitatively for the presence of tumor-infiltrating lymphocytes and histologic location of these lymphocytes. Immunohistochemical staining with monoclonal antibodies directed against CD4 and CD8 was performed in a quantitative manner to identify the lymphocyte subtype present in chordoma tumors. All results were scored independently by two investigators and were confirmed by a senior bone and soft tissue pathologist. Results Seven of 24 chordoma samples exhibited no staining by the anti-HLA-A heavy chain monoclonal antibody HC-A2, two had weak staining intensity, and eight had a heterogeneous staining pattern, with fewer than 60% of chordoma cells exhibiting positive staining results. Four of 24 samples tested were not stained by the anti-HLA-B/C heavy chain monoclonal antibody HC-10, five had weak staining intensity, and 11 displayed a heterogeneous staining pattern. For the anti-β-2-microglobulin monoclonal antibody NAMB-1, staining was detected in all samples, but 11 had weak staining intensity and four displayed a heterogeneous staining pattern. Twenty-one of 24 samples tested had decreased expression in at least one subunit of HLA Class I antigens. No tumors were negative for all three subunits. Lymphocytic infiltration was found in 21 of 24 samples. Lymphocytes were primarily found in the fibrous septae between chordoma lobules but also within the tumor lobules and within the fibrous septae and tumor lobules. Twenty-one of 24 tumors had CD4+ T cells and 11 had CD8+ T cells. Conclusion In chordoma tissue samples, HLA Class I antigen defects commonly were present, suggesting a mechanism for escape from host immunosurveillance. Additionally, nearly half of the tested samples had cytotoxic CD8+ T cells present in chordoma tumors, suggesting that the host may be capable of mounting an immune response against chordoma tumors. The resulting selective pressure imposed on chordoma tumors may lead to the outgrowth of chordoma cell subpopulations that can evade the host's immune system. Clinical relevance These findings have implications in the design of immunotherapeutic strategies for chordoma treatment. T cell recognition of tumor cells requires HLA Class I antigen expression on the targeted tumor cells. Defects in HLA Class I expression may play a role in the clinical course of chordoma and may account for the limited or lack of efficacy of T cell-based immunity triggered by vaccines and/or checkpoint inhibitors.

Immune-based therapies have revolutionized cancer treatments. Cardiovascular sequelae from these treatments, however, have emerged as critical complications, representing new challenges in cardio-oncology. Immune therapies include a broad range of novel drugs, from antibodies and other biologics, including immune checkpoint inhibitors and bispecific T-cell engagers, to cell-based therapies, such as chimeric-antigen receptor T-cell therapies. The recognition of immunotherapy-associated cardiovascular side effects has also catapulted new research questions revolving around the interactions between the immune and cardiovascular systems, and the signaling cascades affected by T cell activation, cytokine release, and immune system dysregulation. Here, we review the specific mechanisms of immune activation from immunotherapies and the resulting cardiovascular toxicities associated with immune activation and excess cytokine production.

Early recognition of adult-onset immunodeficiency associated with neutralizing anti-interferon gamma autoantibodies (anti-IFNγ Abs) remains difficult, and misdiagnoses have been reported. Although febrile lymphadenopathy is among the most common initial manifestations of this disorder, no comprehensive clinicopathologic analysis of lymphadenopathy in patients with anti-IFNγ Abs has been reported. Here, we describe 26 lymph node biopsy specimens from 16 patients. All patients exhibited concurrent disseminated nontuberculous mycobacterial infections, and 31% received a tentative diagnosis of lymphoma at initial presentation. We found 3 distinct histomorphologic patterns: well-formed granuloma (46%), suppurative inflammation or loose histiocytic aggregates (31%), and lymphoproliferative disorder (LPD, 23%). The latter shared some of the features of malignant T-cell lymphoma, IgG4-related disease, and multicentric Castleman disease. Half of the specimens with LPD had monoclonal T cells, and 33.3% were indistinguishable from angioimmunoblastic T-cell lymphoma as per current diagnostic criteria. All lymphadenopathy with LPD features regressed with antibiotics without administration of cytotoxic chemotherapy or immunotherapy. The median follow-up time was 4.3 years. Our study highlights the substantial challenge of distinguishing between lymphoma and other benign lymphadenopathy in the setting of neutralizing anti-IFNγ Abs. Increased vigilance and multidisciplinary discussion among clinicians and pathologists are required to achieve the most appropriate diagnosis and management.

Primary cutaneous CD4+ small/medium T-cell lymphoproliferative disorder is a benign lymphoproliferative disorder composed of small-sized to medium-sized pleomorphic cells expressing a follicular helper T-cell phenotype. Jessner lymphocytic infiltrate and tumid lupus are cutaneous conditions characterized by the presence of rich dermal lymphocytic infiltrates with a superficial, deep, perivascular and periadnexal distribution that include copious amounts of dermal mucin deposition. We report 2 cases of primary cutaneous CD4+ small/medium T-cell lymphoproliferative disorder presenting with markedly increased dermal mucin, mimicking both Jessner lymphocytic infiltrate and tumid lupus and provide a review of the differential diagnosis and highlight key distinguishing features.

Chimeric antigen receptor (CAR) T-cell therapy has quickly emerged as a highly promising treatment for patients with relapsed and refractory multiple myeloma. There are numerous candidates under development, each with their unique characteristics and points of differentiation. The most recent US Food and Drug Administration approval of the first B-cell maturation antigen-targeted CAR-T cell therapy on March 26, 2021, has paved a path forward for the eventual evaluation of more of these investigational agents undergoing clinical trials. Herein, we highlight, from a clinical development perspective, the CAR-T cell therapies farthest along in development with updated data from the American Society of Hematology 2020 annual meeting. We also discuss potential paths of overcoming resistance to these therapies and the future direction for CAR-T cell therapeutics in multiple myeloma.

Background Myeloperoxidase ANCA-associated vasculitis is a major cause of ESKD. Efficacy of anti-CD20 mAb treatment was tested in a mouse model of the disease. Methods MPO immunization induced anti-MPO autoimmunity, and a subnephritogenic dose of sheep anti-mouse GBM globulin triggered GN. Results Anti-CD20 mAb treatment increased the numbers and immunomodulatory capacity of MPO-specific T regulatory cells (Tregs) and attenuated T cell-mediated and humoral anti-MPO autoimmunity and GN. Disabling of Tregs negated the therapeutic benefit of anti-CD20 treatment. The mechanism of enhancement of Treg activity could be attributed to anti-CD20 mAb effects on inducing B cell apoptosis. Administering anti-CD20 mAb-induced apoptotic splenocytes to mice developing anti-MPO GN was as effective as anti-CD20 mAb treatment in inducing Tregs and attenuating both anti-MPO autoimmunity and GN. A nonredundant role for splenic macrophages in mediating the anti-CD20 mAb-induced immunomodulation was demonstrated by showing that administration of anti-CD20 mAb ex vivo-induced apoptotic splenocytes to unmanipulated mice attenuated autoimmunity and GN, whereas deletion of splenic marginal zone macrophages prevented anti-CD20 mAb-induced immunomodulation and treatment efficacy. Six days after administering anti-CD20 mAb to mice with murine anti-MPO GN, cell-mediated anti-MPO responses and GN were attenuated, and Tregs were enhanced, but ANCA levels were unchanged, suggesting humoral autoimmunity was redundant at this time point. Conclusions Collectively, these data suggest that, as well as reducing humoral autoimmunity, anti-CD20 mAb more rapidly induces protective anti-MPO Treg-mediated immunomodulation by splenic processing of anti-CD20-induced apoptotic B cells.

Cytomegalovirus (CMV) and BK virus (BKV) are common viral infections after kidney transplant. Their negative effects on patient and graft outcomes have been well described. However, despite improvement in screening and prophylaxis strategies, CMV and BKV continue to negatively affect both short- and long-term graft survival. Adequate cell-mediated immunity is essential for the control and prevention of opportunistic viral infections, such as CMV and BKV. Therefore, immune reconstitution, in particular T cell recovery, is a key factor in antiviral control after kidney transplantation. Cell-based immunotherapy offers an attractive alternative approach to traditional interventions. Adoptive T cell transfer, via infusions of allogeneic virus-specific T lymphocytes is capable of restoring virus-specific T cell immunity, and are safe and effective in the treatment of viral infections after hematopoietic stem cell transplantation. In this article, we review the emerging role of virus-specific T cell therapy in the management of CMV and BKV after kidney transplantation. On the basis of the available data, virus-specific T cell therapy may be a promising addition to the antiviral treatment armamentarium after kidney transplantation. Future studies are needed to more clearly define the efficacy and risks of virus-specific T cell therapy in the kidney transplant population.

The etiology of biliary atresia (BA) is not known and is likely multifactorial, including a genetic predisposition, a viral or environmental trigger, an aberrant autoimmune response targeting cholangiocytes, and unique susceptibilities of the neonatal bile ducts to injury. Damaged cholangiocytes may express neo self-antigens and elicit autoreactive T-cell-mediated inflammation and B-cell production of autoantibodies. The aim of this study was to discover autoantibodies in BA that correlated with outcomes.An autoantigen microarray encompassing approximately 9,500 autoantigens was used to screen for serum immunoglobulin M (IgM) and immunoglobulin G (IgG) autoantibodies in patients with BA or other liver disease controls. Validation of candidate autoantibodies by enzyme-linked immunosorbent assay on a second cohort of subjects (6-12 months following Kasai portoenterostomy) and correlations of autoantibodies with outcomes were performed (serum bilirubin levels and need for liver transplant in first 2 years of life). Mean anti-chitinase 3-like 1 (CHI3L1), anti-delta-like ligand (DLL-4), and antisurfactant protein D (SFTPD) IgM autoantibodies in BA were significantly higher compared with controls, and IgM autoantibody levels positively correlated with worse outcomes. Immunofluorescence revealed cholangiocyte-predominant expression of CHI3L1, DLL-4, and SFTPD. The humoral autoantibody response was associated with C3d complement activation and T-cell autoimmunity, based on detection of cholangiocyte-predominant C3d co-staining and peripheral blood autoreactive T cells specific to CHI3L1, DLL-4 and SFTPD, respectively.BA is associated with cholangiocyte-predominant IgM autoantibodies in the first year after Kasai portoenterostomy. Anti-CHI3L1, anti-DLL-4, and anti-SFTPD IgM autoantibody correlations with worse outcomes and the detection of C3d on cholangioctyes and antigen-specific autoreactive T cells suggest that autoimmunity plays a role in the ongoing bile duct injury and progression of disease.

Background and aims Hepatocellular carcinoma (HCC) is an aggressive malignancy which is often associated with a complex tumor microenvironment attributable to etiology-induced cellular inflammation. γδ T cells are known to detect and react to chronic inflammation, which is linked to cancer development, progression, and metastasis. Our recent genomic study revealed an increased infiltration of several immune cell types, including γδ T cells, in tumor microenvironments of a Thai HCC subtype associated with a good prognosis. Approach and results Here, we quantified the amount of γδ T cells using a γδ T-cell-specific gene signature in 247 Chinese HCC patients. We also validated the γδ T-cell signature in American HCC patients. Additionally, such an association was only found in tumor transcriptomic data, but not in adjacent nontumor transcriptomic data, suggesting a selective enrichment of γδ T cells in the tumor microenvironment. Moreover, the γδ T-cell signature was positively correlated with the expression of natural killer cell receptor genes, such as NKG2D and cytolytic T-cell genes granzymes and perforin, suggesting a stronger T-cell-mediated cytotoxic activity. Furthermore, we found that the γδ T-cell-specific gene expression is positively correlated with the expression of chemokine (C-C motif) ligand 4 (CCL4)/chemokine (C-C motif) ligand 5 (CCL5) and C-C chemokine receptor type 1 (CCR1)/C-C chemokine receptor type 5 (CCR5), the receptors for γδ T cells. We validated these results using immunohistochemical analysis of formalin-fixed, paraffin-embedded tumor biopsies from 182 HCC patients. Moreover, we found evidence of CCL4/CCL5-mediated recruitment of γδ T cells both in vitro and in a murine orthotopic Hepa1-6 HCC model. Conclusions We propose that CCL4/CCL5 may interact with their receptor, CCR1/CCR5, which may facilitate the recruitment of γδ T cells from peripheral blood or peritumor regions to the tumor regions. Consequently, an increasing infiltration of γδ T cells in tumors may enhance antitumor immunity and improve patients' prognosis.

Success from checkpoint blockade and adoptive cell therapy has brought a new hope in cancer immunotherapy. Adoptive cell therapy involves the isolation of immune cells, ex vivo activation and/or expansion, and reinfusion into the patients, and their effect can be dramatically increased by the incorporation of chimeric antigen receptors specific to molecules expressed on tumor cells. Chimeric antigen receptor T cells have shown exciting results in the treatment of liquid malignancies; nevertheless, they suffer from limitations including severe adverse effects such as cytokine release syndrome and neurotoxicity seen in patients as well as a potential for causing graft-versus-host disease in an allogeneic setting. It is thus imperial to explore innate immune cells including natural killer cells, macrophages, natural killer T cells, and γδ T cells. Here, we provide a broad overview of the major innate immune cells and their potential for adoptive cell therapy and chimeric antigen receptor engineering.

Myeloid-derived suppressor cells (MDSCs) suppress antitumor immune functions. We have observed that an immunomodulator, neem leaf glycoprotein (NLGP), inhibits tumor-resident MDSCs and enhances antitumor CD8+ T cell immunity. NLGP inhibits the number as well as functions of tumor-resident MDSCs (Gr1±CD11b±) and enhances antitumor CD8± T cell immunity by downregulating arginase 1 and inducible nitric oxide synthase production in MDSCs. Accordingly, decreased T cell anergy and helper to regulatory T cell conversion have been observed in the presence of NLGP, which ultimately augments T cell functions. Mechanistically, NLGP-mediated rectification of T cell suppressive functions of MDSCs was primarily associated with downregulation of the interleukin (IL)-10/signal transducer and activator of transcription 3 (STAT3) signaling axis within the tumor microenvironment, as confirmed by knockdown of STAT3 (by STAT3-siRNA) and using IL-10-/- mice. Thus, NLGP-mediated suppression of MDSC functions in tumor hosts is appeared to be another associated effective mechanism for the eradication of murine melanoma by NLGP.

Background and aims Autoimmune hepatitis (AIH) is a chronic liver disease that regularly relapses when immunosuppression is tapered. It is thought to be driven by T-cells, whereas the etiologic impact of an apparently deregulated B lineage system, as evidenced by hypergammaglobulinemia and autoantibodies, remains elusive. We set out to investigate T and B cell repertoires supporting chronic inflammation in AIH. Approach and results T and B cell receptor (TCR/BCR) and human leukocyte antigen (HLA) next-generation immunosequencing were used to record immune signatures from a cohort of 60 patients with AIH and disease controls. Blood and liver B lineage immune metrics were not indicative of a dominant directional antigen selection apart from a slight skewing of IGHV-J genes. More importantly, we found strong AIH-specific TRBV-J skewing not attributable to the HLA-DRB1 specificities of the cohort. This TCR repertoire bias was generated as a result of peripheral T cell (de)selection and persisted in disease remission. Using a clustering algorithm according to antigenic specificity, we identified liver TCR clusters that were shared between patients with AIH but were absent or deselected in patients with other liver pathologies. Conclusions Patients with AIH show profound and persisting T-cell architectural changes that may explain high relapse rates after tapering immunosuppression. Liver T-cell clusters shared between patients may mediate liver damage and warrant further study.

Cutaneous lymphomas, both B-cell and T-cell, are not uncommonly seen in the skin, but those lymphomas exhibiting clonality for both B-cell and T-cell populations are scarce. Characterization of dual receptor rearrangement as primary composite lymphoma versus primary lymphoma with reactionary response is complex and often a challenge that goes unrecognized. In this study, we report a unique case of T-cell gene rearrangement positivity complicating the diagnosis of primary cutaneous low-grade B-cell lymphoma along with a review of reported cases containing dual receptor rearrangement to identify trends among final diagnostic decisions. As one might guess, for cutaneous lymphomas presenting with clonality for both T-cell and B-cell receptors, diagnosis can be difficult and confusing because the differential is broad. The literature suggests the majority of these cases may be cutaneous composite lymphomas. However, immunohistochemical, clinical, and histomorphologic features must all be assessed for an accurate diagnosis, which is critical for proper prognosis and therapy.

Hepatocellular carcinoma (HCC) is a major cause of cancer‐related death worldwide, accounting for 90% of liver cancers. Effective systemic treatments for advanced stage HCC are limited. The recent clinical application of mutated neoantigens as immunotherapeutic targets in several human cancers demonstrated that boosting host T cell responses to these antigens may help control patient tumors. With increased enthusiasm for targeting mutated neoantigens as a strategy in cancer immunotherapy, many clinical trials were initiated to apply mutated neoantigens as targets for the therapy of HCC and other solid tumors. However, recent studies suggest that targeting mutated neoantigens for the immunotherapy of HCC and other solid tumors has pitfalls and may not achieve efficacy without strategic changes. Herein, we discuss the limits of using neoantigens as targets in HCC immunotherapy and suggest alternative strategies to overcome these limits. Importantly, similar limits and alternative strategies are likely applicable to other intermediate and low tumor mutation burden cancers.

A 45-year-old woman presented with a solitary breast nodule that histologically corresponded to a dense dermal/subcutaneous infiltration of atypical cytotoxic T-lymphocytes (CD3+, CD8+, CD56+, TIA-1+, CD5-, CD4-, CD30-, EBV-), resembling subcutaneous panniculitic T-cell lymphoma. The presence of TCRδ gene rearrangement and the absence of βF1 expression let to suspect the diagnosis of primary cutaneous γδT-cell lymphoma. As a consequence of jejunum perforation following chemotherapy treatment, a mucosal atypical lymphoid infiltration with marked epitheliotropism was observed in the resected intestinal sample, and the diagnosis of monomorphic epitheliotropic intestinal T-cell lymphoma (MEITL) was finally established. Disease progression appeared with multiple erythematous plaques showing a dense lichenoid atypical cytotoxic T-cell infiltrate with intense epidermotropism, mimicking primary cutaneous epidermotropic aggressive CD8+ T-cell lymphoma. MEITL is an uncommon and aggressive peripheral T-cell lymphoma that often presents in adults with gastrointestinal symptoms. Secondary cutaneous involvement is a rare phenomenon that may show clinicopathologic and immunohistochemical features that overlap with different subtypes of primary cutaneous cytotoxic T-cell lymphomas. In the absence of gastrointestinal symptoms, the diagnosis may be challenging, and only the evidence of underlying MEITL may allow to establish the definite diagnosis.

BACKGROUND Vestibular schwannomas exhibit a uniquely variable natural history of growth, stability, or even spontaneous regression. We hypothesized that a transitory population of immune cells, or immunomodulation of tumors cells, may influence the growth pattern of schwannomas. We therefore sought to characterize the impact of the immune microenvironment on schwannoma behavior. METHODS Forty-eight vestibular schwannomas with preoperative magnetic resonance imaging and 11 with serial imaging were evaluated for presence of immune infiltrates (including the pan-leukocyte marker Cluster of Differentiation (CD)45, CD4 and CD8 T-cell, and CD68 and CD163 macrophages) as well as expression of immunomodulatory regulators (Programmed Death Ligand 1 (PD-L1), Programmed Death Ligand 2 (PD-L2), LAG-3, TIM-3, V-domain Ig Suppressor of T cell Activation). Maximal diameter, volume, and recurrence were annotated. RESULTS Vestibular schwannomas were characterized by diverse signatures of tumor infiltrating leukocytes and immunomodulatory markers. The median tumor volume was 4.7 cm (Interquartile Range (IQR) 1.0-13.0) and maximum diameter was 2.3 cm (IQR 1.5-3.2). Among tumors with serial imaging, the median volumetric growth was 0.04 cm/mo (IQR 0.01-0.18). Tumor volume and maximum diameter demonstrated strong concordance (R = 0.90; p

The role of cortactin in T-cell acute lymphoblastic leukemia (T-ALL) tissue infiltration has been previously reported. However, its impact on patients' responsiveness to therapy and patient's outcome was not previously addressed. This study was conducted on 60 T-ALL pediatric patients at diagnosis and 10 nonleukemic controls. Cortactin and HS1 expressions were identified by real-time polymerase chain reaction. Cortactin and HS1 expression were significantly higher in T-All patients as compared with controls as well as postinduction levels (P≤0.001 for both). The high cortactin expression was significantly associated with high peripheral white cell counts (P≤0.001), blood blast cells (P≤0.001) and central nervous system (CNS) infiltration (P≤0.001), and early precursor T-ALL subtype (P≤0.001) as compared with the remaining groups. The induction of remission response was significantly higher in T-ALL patients with lower cortactin expression levels as compared with T-ALL patients with higher one (P≤0.001). The high cortactin and HS1 expressions were significantly predictors of CNS infiltrations (hazard ratios [HR]: 1.051, confidence interval [CI]: 1.02-1.13, P=0.04 and HR: 1.87, CI: 1.23-2.091, P=0.002, respectively) and bone marrow relapse (HR: 1.43, CI: 1.18-1.92, P=0.004 and HR: 1.07, CI: 1.01-1.24, P=0.002, respectively). Furthermore, high cortactin expression levels were associated with shorter B-ALL patients' overall survival as compared with those with lower cortactin levels (P=0.002). In conclusion, high expression of cortactin and/or HS1 at diagnosis is a bad prognostic marker of T-ALL patients' outcome. Moreover, cortactin and/or HS1 expression could be used as a biomarker for refining risk stratification of T-ALL.

PURPOSE OF REVIEW: Controlling T cell activity through metabolic manipulation has become a prominent feature in immunology and practitioners of both adoptive cellular therapy (ACT) and hematopoietic stem cell transplantation (HSCT) have utilized metabolic interventions to control T cell function. This review will survey recent metabolic research efforts in HSCT and ACT to paint a broad picture of immunometabolism and highlight advances in each area. RECENT FINDINGS: In HSCT, recent publications have focused on modifying reactive oxygen species, sirtuin signaling, or the NAD salvage pathway within alloreactive T cells, and to a lesser extent on modulating regulatory T cells. In ACT, metabolic interventions that bolster memory T cell development, increase mitochondrial density and function, or block regulatory signals in the tumor microenvironment (TME) have recently been published. SUMMARY: Metabolic interventions control immune responses. In ACT, efforts seek to improve the in vivo metabolic fitness of T cells, while in HSCT energies have focused on blocking alloreactive T cell expansion or promoting regulatory T cells. Methods to identify new, metabolically targetable pathways, as well as the ability of metabolic biomarkers to predict disease onset and therapeutic response, will continue to advance the field towards clinically applicable interventions.

Pulmonary arterial hypertension (PAH) is a fatal disease characterized by increased mean pulmonary arterial pressure. Elevated plasma and lung concentrations of oxidized lipids, including 15-hydroxyeicosatetraenoic acid (15-HETE), have been demonstrated in patients with PAH and animal models. We previously demonstrated that feeding mice with 15-HETE is sufficient to induce pulmonary hypertension, but the mechanisms remain unknown. RNA sequencing data from the mouse lungs on 15-HETE diet revealed significant activation of pathways involved in both antigen processing and presentation and T cell–mediated cytotoxicity. Analysis of human microarray from patients with PAH also identified activation of identical pathways compared with controls. We show that in both 15-HETE–fed mice and patients with PAH, expression of the immunoproteasome subunit 5 is significantly increased, which was concomitant with an increase in the number of CD8/CD69 (cluster of differentiation 8 / cluster of differentiation 69) double-positive cells, as well as pulmonary arterial endothelial cell apoptosis in mice. Human pulmonary arterial endothelial cells cultured with 15-HETE were more prone to apoptosis when exposed to CD8 cells. Cultured intestinal epithelial cells secreted more oxidized lipids in response to 15-HETE, which is consistent with accumulation of circulating oxidized lipids in 15-HETE–fed mice. Administration of an apoA-I (apolipoprotein A-I) mimetic peptide, Tg6F (transgenic 6F), which is known to prevent accumulation of circulating oxidized lipids, not only inhibited pulmonary arterial endothelial cell apoptosis but also prevented and rescued 15-HETE–induced pulmonary hypertension in mice. In conclusion, our results suggest that (1) 15-HETE diet induces pulmonary hypertension by a mechanism that involves oxidized lipid-mediated T cell–dependent pulmonary arterial endothelial cell apoptosis and (2) Tg6F administration may be a novel therapy for treating PAH.

Thrombocytopenia-absent radius (TAR) syndrome is a rare inherited bone marrow failure syndrome not generally associated with acute leukemia. The authors report a case of T-cell acute lymphoblastic leukemia in an adult female individual newly diagnosed with TAR syndrome. A 347-kb microdeletion of chromosome 1q21.1 involving the RBM8A gene was detected within a gain of whole chromosome 1. Next-generation sequencing on fibroblasts confirmed germline heterozygous deletion of RBM8A but on the other allele, noncoding low-frequency regulatory single-nucleotide polymorphism of RBM8A (rs139428292; rs201779890) were not found. The tolerance of the treatment was unusual and mostly marked by a slow hematopoietic recovery leading to a 6-month delay at the beginning of the maintenance phase. Only 5 cases of acute leukemia were reported in patients with TAR syndrome in the literature: 4 acute myeloid leukemia and one B-cell acute lymphoblastic leukemia. This is the first report of T-cell acute lymphoid leukemia occurring in the context of TAR syndrome.

Autoimmune hepatitis (AIH) is an inflammatory disease of the liver. Liver X receptors (LXRs), including the α and β isoforms, are previously known for their anti‐inflammatory activities. The goal of this study is to determine whether and how LXR plays a role in AIH. LXRα gain‐of‐function and loss‐of‐function mouse models were used, in conjunction with the concanavalin A (ConA) model of T‐cell mediated hepatitis. We first showed that the hepatic expression of LXRα was decreased in the ConA model of hepatitis and in human patients with AIH. In the ConA model, we were surprised to find that activation of LXRα in the constitutively activated VP‐LXRα whole‐body knock‐in (LXRα‐KI) mice exacerbated ConA‐induced AIH, whereas the LXRα−/− mice showed attenuated ConA‐induced AIH. Interestingly, hepatocyte‐specific activation of LXRα in the fatty acid binding protein–VP‐LXRα transgenic mice did not exacerbate ConA‐induced hepatitis. Mechanistically, the sensitizing effect of the LXRα‐KI allele was invariant natural killer T (iNKT)–cell dependent, because the sensitizing effect was abolished when the LXRα‐KI allele was bred into the NKT‐deficient CD1d−/− background. In addition, LXRα‐enhanced ConA‐induced hepatitis was dependent on interferon gamma. In contrast, adoptive transfer of hepatic iNKT cells isolated from LXRα‐KI mice was sufficient to sensitize CD1d−/− mice to ConA‐induced AIH. Conclusion: Activation of LXRα sensitizes mice to ConA‐induced AIH in iNKT and interferon gamma–dependent manner. Our results suggest that LXRα plays an important role in the development of AIH., Our results showed that activation of LXRα sensitizes mice to ConA‐induced AIH in an iNKT‐dependent and IFN‐γ‐dependent manner. Our results suggest that LXRα plays an important role in the development of AIH.

Colorectal cancer (CRC) is the third most common malignancy worldwide. Our previous studies have shown that combinatorial treatment with thioridazine and loratadine may effectively inhibit CRC. However, the translation of these research findings to clinical practice was impaired by issues related to a lack of therapeutic specificity and to immune evasion. Toll-like receptor (TLR) agonists have been used as adjuvants to enhance the effectiveness of cancer vaccines. The aim of this study was to evaluate the therapeutic efficiency of immunotherapy with thioridazine and loratadine in combination with resiqumiod (R848), a small-molecule TLR7 agonist, in suppressing CRC growth in a mouse model. Twenty-four BALB/c mice were randomly assigned to treatment with PBS, R848, thioridazine + loratadine, or thioridazine + loratadine + R848. Cytokine levels were measured with ELISA. Overall survival, as well as tumor volume and tumor weight, was recorded. Cytotoxicity was measured by counting the numbers of CD8 and CD3-positive (CD8CD3) or CD4 and CD3-positive (CD3CD4) T-cells. The immune response induced by cytokines (as interferon-γ, interleukin-6, and tumor necrosis factor-α) was significantly stronger in mice treated with thioridazine + loratadine + R848. Moreover, thioridazine + loratadine + R848 significantly delayed tumor development and prolonged survival, which was associated with enhanced immune response and dendritic cell maturation. This study suggested that thioridazine + loratadine + R848 combinatorial treatment may be effective in overcoming immune evasion by tumor cells, with promising therapeutic potential in CRC.

International audience; Introduction and aims: Changes in the composition of the gut microbiota in patients with colorectal cancer (CRC) compatible with a contribution of the gut microbiota in carcinogenesis have been reported. In particular, a decrease Faecalibacterium prausnitzii has been identified. A CD4CD8αα, double-positive lymphocyte population (DP8α) has recently been demonstrated in the human colon and blood with regulatory functions and specificity for F. prausnitzii. Here, we aimed to detect dysbiosis in the fecal microbiome of patients with CRC by metagenomic analysis, and to look for changes in the levels of DP8α circulating T cells specific for F. prausnitzii in these patients.Patients and methods: Patients with CRC and control subjects were prospectively included. None had received antibiotics in the previous month or any anti-tumor treatment. A stool sample was collected for each participant, and analyzed by shotgun sequencing. The DP8α T cell population was identified and quantified on fresh whole blood by flow cytometry with anti-CD45, anti-CD3, anti-CD4 and anti-CD8α co-labeling.Results: Twenty-one patients with CRC and 20 controls subjects were included. We found that mean relative abundance of five species was significantly decreased in CRC patients compared with controls, including F. prausnitzii, Barnesiella intestinihominis, Alistipes finegoldii, Bacteroides eggerthii and Eubacterium siraeum. We also found that the DP8α T cell population was significantly decreased in the blood of CRC patients compared with controls.Conclusion: In our work, we showed that a reduced abundance of F. prausnitzii in CRC patients was associated to a significant decrease in the circulating DP8α Treg population, suggesting a potential involvement of reduced activity of DP8α T cells in colonic carcinogenesis. These findings open new diagnostic and therapeutic strategies for CRC.

Objective: The aim of this study was to investigate if there is a causal relationship between circulating levels of TIM-1 (T-cell immunoglobulin and mucin domain 1) and incidence of stroke. Approach and Results: Plasma TIM-1 was analyzed in 4591 subjects (40% men; mean age, 57.5 years) attending the Malmö Diet and Cancer Study. Incidence of stroke was studied in relation to TIM-1 levels during a mean of 19.5 years follow-up. Genetic variants associated with TIM-1 (pQTLs [protein quantitative trait loci]) were examined, and a 2-sample Mendelian randomization analysis was performed to explore the role of TIM-1 in stroke using summary statistics from our pQTLs and the MEGASTROKE consortium. A total of 416 stroke events occurred during follow-up, of which 338 were ischemic strokes. After risk factor adjustment, TIM-1 was associated with increased incidence of all-cause stroke (hazards ratio for third versus first tertile, 1.44 [95% CI, 1.10–1.87]; P for trend, 0.004), and ischemic stroke (hazards ratio, 1.42 [95% CI, 1.06–1.90]; P for trend, 0.011). Nineteen independent lead SNPs, located in three genomic risk loci showed significant associations with TIM-1 ( P −8 ). A 2-sample Mendelian Randomization analysis suggested a causal effect of TIM-1 on stroke (β=0.083, P =0.0004) and ischemic stroke (β=0.102, P =7.7×10 −5 ). Conclusions: Plasma level of TIM-1 is associated with incidence of stroke. The genetic analyses suggest that this could be a causal relationship.

Background Antiglomerular basement membrane (anti-GBM) disease is associated with HLA-DRB1*1501 (the major predisposing genetic factor in the disease), with α3127-148 as a nephritogenic T and B cell epitope. Although the cause of disease remains unclear, the association of infections with anti-GBM disease has been long suspected. Methods To investigate whether microbes might activate autoreactive T and B lymphocytes via molecular mimicry in anti-GBM disease, we used bioinformatic tools, including BLAST, SYFPEITHI, and ABCpred, for peptide searching and epitope prediction. We used sera from patients with anti-GBM disease to assess peptides recognized by antibodies, and immunized WKY rats and a humanized mouse model (HLA-DR15 transgenic mice) with each of the peptide candidates to assess pathogenicity. Results On the basis of the critical motif, the bioinformatic approach identified 36 microbial peptides that mimic human α3127-148. Circulating antibodies in sera from patients with anti-GBM recognized nine of them. One peptide, B7, derived from Actinomyces species, induced proteinuria, linear IgG deposition on the GBM, and crescent formation when injected into WKY rats. The antibodies to B7 also targeted human and rat α3127-148. B7 induced T cell activation from human α3127-148-immunized rats. T cell responses to B7 were detected in rats immunized by Actinomyces lysate proteins or recombinant proteins. We confirmed B7's pathogenicity in HLA-DR15 transgenic mice that developed kidney injury similar to that observed in α3135-145-immunized mice. Conclusions Sera from patients with anti-GBM disease recognized microbial peptides identified through a bioinformatic approach, and a peptide from Actinomyces induced experimental anti-GBM GN by T and B cell crossreactivity. These studies demonstrate that anti-GBM disease may be initiated by immunization with a microbial peptide.

Systemic Epstein-Barr virus-positive T-cell and natural killer (NK)-cell lymphoproliferative diseases of childhood are a group of lethal diseases mostly affecting children and young adults. The Ohshima Grading System and the 2017 World Health Organization (WHO) classification have been used for classifying this spectrum, but these systems have not been validated externally and compared. Therefore, we examined 36 cases of systemic Epstein-Barr virus-positive T-cell and NK-cell lymphoproliferative diseases of childhood with long-term follow-up, from Southwest China, to systematically summarize the clinicopathologic features and to validate and compare the Ohshima Grading System and the 2017 WHO classification in discrimination ability, predictive accuracy, concordance indices, and explained variation. Clinically, our cohort showed severe manifestations and poor prognoses. Morphologically, the hematopoietic and lymphoid specimens showed proliferation of small-sized to medium-sized bland-looking lymphocytes that might mask disease severity, whereas other extranodal lesions showed a disorganized to obliterated architecture infiltrated by medium-sized to large-sized, subtle to obvious atypical cells, which may mimic extranodal NK/T-cell lymphoma. Immunophenotypically, our cases mainly originate from CD8 αβ T cells. Therefore, clinical and pathologic features should be equally considered to avoid missed diagnosis or misdiagnosis. In addition, the 2017 WHO classification shows a flexible grasp of pathologic features, thus classifying some cases (polymorphic and monoclonal cases with fulminant course) more reasonably; thereby, it showed statistically improved results compared with the Ohshima Grading System. However, underestimating the risk of some polyclonal cases and imprecisely discriminating monoclonal cases at diagnosis are common dilemmas in both systems. Therefore, the construction of a comprehensive grading algorithm for improved prognostic value and precise diagnosis requires additional studies.

OBJECTIVE To investigate long-term persistence of HIV-specific lymphocyte immunity in perinatally HIV-infected children treated within the first year of life. DESIGN Twenty perinatally HIV-infected children who received ART therapy within the first year of life (early treated) and with stable viral control (>5 years) were grouped according to their serological response to HIV. METHODS Western blot analysis and ELISA defined 14 HIV-seropositive and six seronegative patients. Frequencies of gp140-specific T-cell and B-cell, and T-cell cytokine production were quantified by flow cytometry in both seronegatives and seropositives. Transcriptional signatures in purified gp140-specific B-cell subsets, in response to in-vitro stimulation with HIV peptides was evaluated by multiplex RT-PCR. RESULTS Gp140-specific T cells and B cells persist at similar levels in both groups. A higher production of IL-21 in gp140-specific T cells was found in seropositives vs. seronegatives (P = 0.003). Gene expression in switched IgM-IgD- gp140-specific memory B cells after stimulation with HIV peptides in vitro demonstrated a differential expression of genes involved in signal transduction and activation after BCR/TLR triggering and B-cell activation. Genes relating to antibody production (PRDM1) and T-B cognate stimulation (CXCR4, IL21R) were differentially induced after in-vitro stimulation in seronegatives vs. seropositives suggesting a truncated process of B-cell maturation. CONCLUSION HIV-specific memory B and T cells persist in early treated regardless their serological status. Seronegatives and seropositives are distinguished by gp140-specific T-cell function and by distinct transcriptional signatures of gp140-specific B cells after in-vitro stimulation, presumably because of a different antigen exposure. Such qualitative insights may inform future immunotherapeutic interventions.

Background Identifying biomarkers to predict kidney transplant failure and to define new therapeutic targets requires more comprehensive understanding of the immune response to chronic allogeneic stimulation. Methods We investigated the frequency and function of CD8+ T cell subsets-including effector memory (EM) and terminally differentiated EM (TEMRA) CD8+ T cells-in blood samples from 284 kidney transplant recipients recruited 1 year post-transplant and followed for a median of 8.3 years. We also analyzed CD8+ T cell reactivity to donor-specific PBMCs in 24 patients who had received living-donor kidney transplants. Results Increased frequency of circulating TEMRA CD8+ T cells at 1 year post-transplant associated with increased risk of graft failure during follow-up. This association remained after adjustment for a previously reported composite of eight clinical variables, the Kidney Transplant Failure Score. In contrast, increased frequency of EM CD8+ T cells associated with reduced risk of graft failure. A distinct TEMRA CD8+ T cell subpopulation was identified that was characterized by expression of FcγRIIIA (CD16) and by high levels of proinflammatory cytokine secretion and cytotoxic activity. Although donor-specific stimulation induced a similar rapid, early response in EM and TEMRA CD8+ T cells, CD16 engagement resulted in selective activation of TEMRA CD8+ T cells, which mediated antibody-dependent cytotoxicity. Conclusions At 1 year post-transplant, the composition of memory CD8+ T cell subsets in blood improved prediction of 8-year kidney transplant failure compared with a clinical-variables score alone. A subpopulation of TEMRA CD8+ T cells displays a novel dual mechanism of activation mediated by engagement of the T-cell receptor or of CD16. These findings suggest that TEMRA CD8+ T cells play a pivotal role in humoral and cellular rejection and reveal the potential value of memory CD8+ T cell monitoring for predicting risk of kidney transplant failure.