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Acute and chronic cutaneous graft‐versus‐host disease (GVHD) are common complications following hematopoietic stem cell transplantation (HSCT) in pediatric patients. In this retrospective study, we explored the risk factors and clinical characteristics of acute and chronic cutaneous GVHD in a case series of children undergoing HSCT at a tertiary referral hospital. We found that 36% of acute cutaneous GVHD was severe and these patients were more likely to have an unrelated donor, and that children with acute cutaneous GVHD who progressed to chronic cutaneous GVHD had a higher proportion of malignant diseases, total body irradiation, and bronchiolitis obliterans compared to those who did not progress to chronic cutaneous GVHD. Our study highlights the importance of identifying and monitoring these high‐risk patients to improve the clinical management and outcomes of cutaneous GVHD in pediatric HSCT recipients. [ABSTRACT FROM AUTHOR]

Human leukocyte antigen (HLA)-DPB1 antigens are mismatched in approximately 70% of allogeneic hematopoietic stem cell transplantations (allo-HSCT) from HLA 10/10 matched unrelated donors. HLADP-mismatched transplantation was shown to be associated with an increase in acute graft-versus-host disease (GVHD) and a decreased risk of leukemia relapse due to the graft-versus-leukemia (GVL) effect. Immunotherapy targeting mismatched HLA-DP is considered reasonable to treat leukemia following alloHCT if performed under non-inflammatory conditions. Therefore, we isolated CD4+ T cell clones that recognize mismatched HLA-DPB1 from healthy volunteer donors and generated T cell receptor (TCR)- gene-modified T cells for future clinical applications. Detailed analysis of TCR-T cells expressing TCR from candidate clone #17 demonstrated specificity to myeloid and monocytic leukemia cell lines that even expressed low levels of targeted HLA-DP. However, they did not react to non-hematopoietic cell lines with a substantial level of targeted HLA-DP expression, suggesting that the TCR recognized antigenic peptide is only present in some hematopoietic cells. This study demonstrated that induction of T cells specific for HLA-DP, consisting of hematopoietic cell lineage-derived peptide and redirection of T cells with cloned TCR cDNA by gene transfer, is feasible when using careful specificity analysis. [ABSTRACT FROM AUTHOR]

Graft versus host disease (GVHD) can occur at any period post allogeneic hematopoietic stem cell transplantation as a common clinical complication contributing to significant morbidity and mortality. Acute GVHD develops in approximately 30-50% of patients receiving transplants from matched related donors. High doses of steroids are used as first-line treatment, but are unsuccessful in around 40% of patients, resulting in the diagnosis of steroidrefractory acute GVHD. Consensus has yet to develop for the management of steroid-refractory acute GVHD, and prognosis at six months has been estimated at around 50%. Thus, it is critical to find effective treatments that increase survival of steroid-refractory acute GVHD. This article describes the currently known characteristics, pathophysiology, and treatments for GVHD, with a special focus on recent advances in cell therapies. In particular, a novel cell therapy using decidua stromal cells (DSCs) was recently shown to have promising results for acute GVHD, with improved effectiveness over previous treatments including mesenchymal stromal cells. At the Karolinska Institute, severe acute GVHD patients treated with placenta-derived DSCs supplemented with either 5% albumin or 10% AB plasma displayed a one-year survival rate of 76% and 47% respectively. Furthermore, patients with steroid-refractory acute GVHD, displayed survival rates of 73% with albumin and 31% with AB plasmasupplemented DSCs, compared to the 20% survival rate in the mesenchymal stromal cell control group. Adverse events and deaths were found to be attributed only to complications of hematopoietic stem cell transplant and GVHD, not to the study intervention. ASC Therapeutics, Inc, in collaboration with the Karolinska Institute, will soon initiate a phase 2 multicenter, open-label study to further assess the efficacy and safety of intravenous DSC treatment in sixty patients with Grade II-IV steroid-refractory acute GVHD. This novel cell therapy represents a promising treatment to combat the poor prognosis that steroid-refractory acute GVHD patients currently face. [ABSTRACT FROM AUTHOR]

PURPOSE: Tacrolimus is a commonly used immunosuppressant medication after lung transplantation. In rare cases, tacrolimus causes a medication-induced optic neuropathy (TON) that can lead to significant vision loss. OBSERVATIONS: In this series, we describe three cases of TON, 1-10 years after medication use. Two patients were young (22yr and 33yr) females with cystic fibrosis. The last case was a 65yr male with idiopathic pulmonary fibrosis. In 2/3 cases tacrolimus serum levels were normal. Visual acuity ranged from 20/20 to 20/300, and vision loss occurred acutely to sub-acutely, over a span of 2-3 months. CONCLUSIONS AND IMPORTANCE: As presented here, TON can be highly variable. MRI findings are often non-specific, from normal brain findings to extensive white matter changes. There remains an unclear association with graft-versus-host disease and reduced kidney function. Visual findings are often subtle, including color vision aberration and peripheral visual field deficits, both of which usually require an ophthalmologic evaluation. When diagnosed in a timely fashion, TON is at least partially reversible in up to half of all cases. While rare, the cases described here support post-lung transplant ophthalmologic evaluation in those taking high-risk medications.

Abstract We investigated the proteins of erythrocytes from stem cell transplantation patients and found decreased expression of band3 and C‐terminal‐truncated peroxiredoxin 2 (PRDX2) only during severe graft‐versus‐host disease (GVHD), using time‐of‐flight mass spectrometry (TOF‐MS) analysis and Western blotting. During the same period, PRDX2 dimerization and calpain‐1 activation were observed, indicating severe oxidative stress. We also found a putative cleavage site for calpain‐1 in the C‐terminal‐truncated site of PRDX2. Decreased band3 expression impairs the plasticity and stability of erythrocytes, and C‐terminal‐truncated PRDX2 induces irreversible dysfunction of antioxidant activity. These effects may exacerbate microcirculation disorders and the progression of organ dysfunction.

Neurological immune-related adverse events (irAEs) are rare toxicities that occur following immune checkpoint inhibitor therapy. We propose that patients with thymic malignancies and graft-versus-host disease (GVHD) are predisposed to irAEs. We present two asymptomatic patients, one with thymoma and another with GVHD, who developed abnormal brain MRIs after treatment with programmed cell death protein 1 inhibitors. The first patient, with thymic cancer and thymoma, developed pontine enhancing MRI lesions following treatment with pembrolizumab. The second patient, with prior GVHD, developed pachymeningeal enhancement following treatment with nivolumab. IrAEs with abnormal MRI studies, despite asymptomatology, have significant impact on the treatment strategy for these patients.

The efficacy of allogeneic hematopoietic stem cell transplantation (allo-HSCT) is limited by the occurrence of acute and chronic graft-versus-host disease (GVHD). We have recently demonstrated that obesity results in exacerbated acute gastrointestinal GVHD in both mouse models and clinical outcomes due to increased pro-inflammatory cytokine responses and microbiota alterations. We therefore wanted to delineate the role of the various parameters in obesity, adiposity, effects of high-fat (HF) diet, and the role of microbiome on GVHD pathogenesis, by taking advantage of a mouse strain resistant to diet-induced obesity (DIO). Female BALB/c mice are resistant to DIO phenotype with approximately 50% becoming DIO under HF diets. The DIO-susceptible recipients rapidly succumb to acute gut GVHD, whereas the DIO-resistant recipient littermates, which do not become obese, are partially protected from GVHD, indicating that being on HF diet alone contributes to but is not the primary driver of GVHD. Microbiome assessment revealed restricted diversity in both cohorts of mice, but coprophagy normalizes the microbiota in mice housed together. We then individually housed DIO-resistant, DIO-susceptible, and lean control mice. Notably, each of the individually housed groups demonstrates marked restricted diversity that has been shown to occur from the stress of single housing. Despite the restricted microbiome diversity, the GVHD pathogenesis profile remains consistent in the group-housed mice, with the lean control single-housed mice exhibiting no acute GVHD and DIO-resistant recipients showing again partial protection. These results demonstrate that the deleterious effects of obesity on acute gut GVHD are critically dependent on adiposity with the HF diet also playing a lesser role, and the microbiome alterations with obesity instead appear to fuel ongoing acute GVHD processes.

IntroductionExtracorporal Photophoresis (ECP) is in clinical use for steroid-refractory and steroid-dependent acute GVHD (SR-aGVHD). Based on recent Phase-III study results, ruxolitinib has become the new standard of care for SR-aGVHD. Our aim was to collect comparative data between ruxolitinib and ECP in SR-aGVHD in order to improve the evidence base for clinical decision making. MethodsWe asked EBMT centers if they were willing to participate in this study by completing a data form (Med-C) with detailed information on GVHD grading, -therapy, -dosing, -response and complications for each included patient.Results31 centers responded positively (14%) and we included all patients receiving alloSCT between 1/2017-7/2019 and treated with ECP or ruxolitinib for SR-aGVHD grades II-IV from these centers. We identified 53 and 40 patients with grades II-IV SR-aGVHD who were treated with ECP and ruxolitinib, respectively. We performed multivariate analyses adjusted on grading and type of SR-aGVHD (steroid dependent vs. refractory). At day+90 after initiation of treatment for SR-aGVHD we found no statistically significant differences in overall response. The odds ratio in the ruxolitinib group to achieve overall response vs. the ECP group was 1.13 (95% CI = [0.41; 3.22], p = 0.81). In line, we detected no statistically significant differences in overall survival, progression-free survival, non-relapse mortality and relapse incidence.DiscussionThe clinical significance is limited by the retrospective study design and the current data can’t replace prospective studies on ECP in SR-aGVHD. However, the present results contribute to the accumulating evidence on ECP as an effective treatment option in SR-aGVHD.

ABSTRACTMany patients with hematological malignancies, such as acute myeloid leukemia, receive an allogeneic hematopoietic cell transplantation (HCT) to cure their underlying condition. Allogeneic HCT recipients are exposed to various elements during the pre-, peri- and post-transplant period that can disrupt intestinal microbiota, including chemo- and radiotherapy, antibiotics, and dietary changes. The dysbiotic post-HCT microbiome is characterized by low fecal microbial diversity, loss of anaerobic commensals, and intestinal domination, particularly by Enterococcus species, and is associated with poor transplant outcomes. Graft-versus-host disease (GvHD) is a frequent complication of allogeneic HCT caused by immunologic disparity between donor and host cells and results in tissue damage and inflammation. Microbiota injury is particularly pronounced in allogeneic HCT recipients who go on to develop GvHD. At present, manipulation of the microbiome for example, via dietary interventions, antibiotic stewardship, prebiotics, probiotics, or fecal microbiota transplantation, is widely being explored to prevent or treat gastrointestinal GvHD. This review discusses current insights into the role of the microbiome in GvHD pathogenesis and summarizes interventions to prevent and treat microbiota injury.

IntroductionAllogeneic hematopoietic stem cell transplantation (allo-HCT) is a standard treatment for relapsed/refractory B-cell acute lymphoblastic leukemia (r/r B-ALL). However, about 30-40% of patients still relapse after HCT. Chimeric antigen receptor-modified T-cell (CAR-T) therapy has been proven effective in the treatment of relapsed or refractory B-ALL.Patients and methodsWe report a cohort of 30 B-ALL patients, who relapsed after HCT and were enrolled in the 4SCAR2.0 study, receiving CD19 CAR-Ts alone (20 patients), or two types of CAR-Ts targeting CD19, CD22, CD38 or CD123 antigens (10 patients), depending on the tumor antigen expression profile. These patients had extramedullary (EM) relapse or bone marrow (BM) relapse, or both. Based on the GVHD history, donor chimerism, and the available T-cell source, 25 patients received allogeneic donor CAR-Ts, and 5 patients received autologous CAR-T treatment. ResultsAll 20 patients receiving a single CD19 CAR-T infusion achieved a minimal residual disease (MRD) remission within 60 days. The remaining 10 patients, due to low CD19 antigen expression profile, received 2 CAR-T products given on the same day, and 9 of 10 achieved complete remission (CR) and one had disease progression within 60 days. After CAR-T infusion, no cytokine release syndrome (CRS) was observed in 14 patients, and 16 patients experienced grade 1 CRS, and there was no neurotoxicity. Seventeen of the 30 patients who achieved remission (57%) remained in continuous remission following CAR-T treatment with a median follow-up period of 2 years and a median duration of remission of 12 months (range: 2.8 months - 67 months). Twelve out of 29 patients (41%) who achieved remission, subsequently relapsed at a median of 6.3 months (range: 2.8 months - 22.3 months) after CAR-T treatment. In summary, 29 patients (97%) achieved MRD negative remission within 60 days of therapy with a single or double CAR-T infusion, and seven patients remained in durable remission (7/30, 23%) after more than 2 years of follow-up. DiscussionThe tumor antigen profile-guided precision 4SCAR2.0 regimen for the treatment of r/r B-ALL after allo-HCT was highly effective with low toxicity. This approach warrants extended follow-up and further studies. Clinical trial registrationClinicalTrials.gov, identifier NCT03125577.

BackgroundSince the early 1990s, Ultraviolet (UV) A1 phototherapy has been described as an effective and safe treatment of a multitude of skin disorders. However, after 30 years, its use has remained limited to few dermatological centers.ObjectiveTo analyze the changes over the years and the current position of UVA1 phototherapy through a Real-World Evidence (RWE) study at a single tertiary referral center.MethodsWe reviewed the medical files of 740 patients treated between 1998 and 2022. Treatment results were collected, efficacy was assessed by a grading scale and acute adverse effects were registered.ResultsWe treated patients with 26 different diseases. We registered marked improvement (MI) or complete remission (CR) in 42.8% of patients with morphea, 50% with Urticaria Pigmentosa, 40.7% with Granuloma annulare and 85.7% with skin sarcoidosis. Good results were obtained also in the treatment of chronic Graft Versus Host Disease (GVHD), Eosinophilic Fasciitis, Sclero-atrophic Lichen, skin manifestations of systemic lupus erythematosus and psoriasis of HIV+ patients. Systemic Sclerosis, Romberg’s Syndrome, Bushke’s Scleredema, Nephrogenic Fibrosing Dermopathy, REM Syndrome, Follicular Mucinosis, Pretibial Myxedema, Scleromyxedema, pemphigus foliaceus, chronic cutaneous lupus erythematosus, erythroderma of Netherton Syndrome and Necrobiosis Lipoidica were no or poorly responsive. In clinical indications where UVA1 was used as a second line phototherapy after narrow-band (NB)-UVB, we saw good MI or CR rates in Mycosis Fungoides (57% of patients), Atopic Dermatitis (33.9%), Pitiryasis Lichenoides chronica (50%), Pityriasis Lichenoides et varioliformis acute (75%) and Lymphomatod Papulosis (62.5%). Short-term adverse events were uncommon and mild.ConclusionOver the past decade, the annual number of treated patients has progressively declined for several reasons. Firstly, UVA1 phototherapy has taken a backseat to the cheaper and more practical NB-UVB phototherapy, which has proven effective for common indications. Secondly, the emergence of new, safe, and effective drugs for conditions such as atopic dermatitis, GVHD, and connective tissue disorders. Finally, our research has shown that UVA1 therapy is often ineffective or minimally effective for some rare diseases, contrary to previous case reports and small case series. Nonetheless, UVA1 continues to be a valuable treatment option for patients with specific skin disorders.

Graft versus host disease (GVHD) can occur at any period post allogeneic hematopoietic stem cell transplantation as a common clinical complication contributing to significant morbidity and mortality. Acute GVHD develops in approximately 30-50% of patients receiving transplants from matched related donors. High doses of steroids are used as first-line treatment, but are unsuccessful in around 40% of patients, resulting in the diagnosis of steroid-refractory acute GVHD. Consensus has yet to develop for the management of steroid-refractory acute GVHD, and prognosis at six months has been estimated at around 50%. Thus, it is critical to find effective treatments that increase survival of steroid-refractory acute GVHD. This article describes the currently known characteristics, pathophysiology, and treatments for GVHD, with a special focus on recent advances in cell therapies. In particular, a novel cell therapy using decidua stromal cells (DSCs) was recently shown to have promising results for acute GVHD, with improved effectiveness over previous treatments including mesenchymal stromal cells. At the Karolinska Institute, severe acute GVHD patients treated with placenta-derived DSCs supplemented with either 5% albumin or 10% AB plasma displayed a one-year survival rate of 76% and 47% respectively. Furthermore, patients with steroid-refractory acute GVHD, displayed survival rates of 73% with albumin and 31% with AB plasma-supplemented DSCs, compared to the 20% survival rate in the mesenchymal stromal cell control group. Adverse events and deaths were found to be attributed only to complications of hematopoietic stem cell transplant and GVHD, not to the study intervention. ASC Therapeutics, Inc, in collaboration with the Karolinska Institute, will soon initiate a phase 2 multicenter, open-label study to further assess the efficacy and safety of intravenous DSC treatment in sixty patients with Grade II-IV steroid-refractory acute GVHD. This novel cell therapy represents a promising treatment to combat the poor prognosis that steroid-refractory acute GVHD patients currently face.

Allogeneic hematopoietic cell transplantation (allo-HCT) is a promising therapeutic option for hematologic malignancies. However, the clinical benefits of allo-HCT are limited by the development of complications including graft-versus-host disease (GVHD). Conditioning regimens, such as chemotherapy and irradiation, which are administered to the patients prior to allo-HCT, can disrupt the endoplasmic reticulum (ER) homeostasis, and induce ER stress in the recipient's cells. The conditioning regimen activates antigenpresenting cells (APCs), which, in turn, activate donor cells, leading to ER stress in the transplanted cells. The unfolded protein response (UPR) is an evolutionarily conserved signaling pathway that manages ER stress in response to cellular stress. UPR has been identified as a significant regulatory player that influences the function of various immune cells, including T cells, B cells, macrophages, and dendritic cells (DCs), in various disease progressions. Therefore, targeting the UPR pathway has garnered significant attention as a promising approach for the treatment of numerous diseases, such as cancer, neurodegeneration, diabetes, and inflammatory diseases. In this review, we summarize the current literature regarding the contribution of ER stress response to the development of GVHD in both hematopoietic and non-hematopoietic cells. Additionally, we explore the potential therapeutic implications of targeting UPR to enhance the effectiveness of allo-HCT for patients with hematopoietic malignancies. [ABSTRACT FROM AUTHOR]

Background: Methotrexate (MTX), utilized as a graft-versus-host disease (GvHD) prophylactic agent in allogeneic hematopoietic stem cell transplantation (allo-HSCT), has been proven to effectively decrease the occurrence of the peri-engraftment syndrome (Peri-ES) and acute GvHD (aGvHD). Changes in the pharmacodynamics of MTX are closely associated with gene polymorphisms in genes encoding drug-metabolizing enzymes and transporters. Nevertheless, the current studies mainly concentrate on leukemia or autoimmune diseases, and limited studies on allo-HSCT were reported. Methods: Here, we retrospectively assessed the relationship between MTX-related transporter and metabolizing enzyme gene polymorphisms, clinical characteristics, and outcomes in 57 pediatric patients who received haploid HSCT (haplo-HSCT) with malignant tumors at a single center. Results: We discovered all gene polymorphisms were in the Hardy–Weinberg equilibrium in our cohort. We discovered a significant correlation between platelet recovery time and ABCB1 (1236C>T) (p = 0.042). Compared with patients with SLCO1B1 (1865+4846T>C) TT, patients with SLCO1B1 (1865+4846T>C) TC/CC had an increased incidence of Peri-ES (p = 0.030). Based on the multivariate Cox analysis, we discovered that SLCO1B1 (1865+4846T>C) TT genotype was an independent protective factor for Peri-ES morbidity (hazard ratio (HR) = 0.464, p = 0.031), and the dose of mononuclear cells reinfused was significantly correlated with II–IV aGvHD (HR = 2.604, p = 0.039). Conclusion: In summary, our findings prove that the host’s genotypes might modify the risk of developing Peri-ES, contribute to a better understanding of the inter-individual difference in efficacy, and facilitate the development of individualized approaches to GvHD prophylaxis. [ABSTRACT FROM AUTHOR]

Acute graft-versus-host disease (GvHD) remains the biggest clinical challenge and prognosis-determining complication after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Donor T cells are acceptedly key mediators of alloreactivity against host tissues and here especially the gut. In support of previous studies, we found that the intestinal intra-epithelial lymphocyte (IEL) compartment was dynamically regulated in the course of MHC class I full mismatch allo-HSCT. However, while intestinal epithelial cell (IEC) damage endangers the integrity of the intestinal barrier and is a core signature of intestinal GvHD, the question whether and to what degree IELs are contributing to IEC dysregulation is poorly understood. To study lymphoepithelial interaction, we employed a novel ex vivo T cell/organoid co-culture model system. Here, allogeneic intra-epithelial T cells were superior in inducing IEC death compared to syngeneic IEL and allogeneic non-IEL T cells. The ability to induce IEC death was predominately confined to TCRp+ T cells and was executed in a largely IFNγ-dependent manner. Alloreactivity required a diverse T cell receptor (TCR) repertoire since IELs genetically modified to express a TCR restricted to a single, non-endogenous antigen failed to mediate IEC pathology. Interestingly, minor histocompatibility antigen (miHA) mismatch was sufficient to elicit IEL-driven IEC damage. Finally, advanced live cell imaging analyses uncovered that alloreactive IELs patrolled smaller areas within intestinal organoids compared to syngeneic controls, indicating their unique migratory properties within allogeneic IECs. Together, we provide here experimental evidence for the utility of a co-culture system to model the cellular and molecular characteristics of the crosstalk between IELs and IEC in an allogeneic setting ex vivo. In the light of the emerging concept of dysregulated immune-epithelial homeostasis as a core aspect of intestinal GvHD, this approach represents a novel experimental system to e.g. screen therapeutic strategies for their potential to normalize T cell/IEC- interaction. Hence, analyses in pre-clinical in vivo allo-HSCT model systems may be restricted to hereby positively selected, promising approaches. [ABSTRACT FROM AUTHOR]

The successful treatment of patients affected by B-cell malignancies with Chimeric Antigen Receptor (CAR)-T cells represented a breakthrough in the field of adoptive cell therapy (ACT). However, CAR-T therapy is not an option for every patient, and several needs remain unmet. In particular, the production of CAR-T cells is expensive, labor-intensive and logistically challenging; additionally, the toxicities deriving from CAR-T cells infusion, such as cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS), have been documented extensively. Alternative cellular therapy products such as Cytokine-induced killer (CIK) cells have the potential to overcome some of these obstacles. CIK cells are a heterogeneous population of polyclonal CD3+CD56+ T cells with phenotypic and functional properties of NK cells. CIK cell cytotoxicity is exerted in a major histocompatibility complex (MHC)-unrestricted manner through the engagement of natural killer group 2 member D (NKG2D) molecules, against a wide range of hematological and solid tumors without the need for prior antigen exposure or priming. The foremost potential of CIK cells lies in the very limited ability to induce graft-versus-host disease (GvHD) reactions in the allogeneic setting. CIK cells are produced with a simple and extremely efficient expansion protocol, which leads to a massive expansion of effector cells and requires a lower financial commitment compared to CAR-T cells. Indeed, CAR-T manufacturing involves the engineering with expensive GMP-grade viral vectors in centralized manufacturing facilities, whereas CIK cell production is successfully performed in local academic GMP facilities, and CIK cell treatment is now licensed in many countries. Moreover, the toxicities observed for CAR-T cells are not present in CIK cell-treated patients, thus further reducing the costs associated with hospitalization and post-infusion monitoring of patients, and ultimately encouraging the delivery of cell therapies in the outpatient setting. This review aims to give an overview of the limitations of CAR-T cell therapy and outline how the use of CIK cells could overcome such drawbacks thanks to their unique features. We highlight the undeniable advantages of using CIK cells as a therapeutic product, underlying the opportunity for further research on the topic. [ABSTRACT FROM AUTHOR]

CD4 immune reconstitution (IR) after allogeneic hematopoietic cell transplant (allo-HCT) correlates with lower non-relapse mortality (NRM), but its impact on leukemia relapse remains less clear, especially in children. We studied the correlation between IR of lymphocyte subsets and HCT outcomes in a large cohort of children/young adults with hematological malignancies. We retrospectively analyzed CD4, CD8, B-cell and natural killer (NK) cell reconstitution in patients after first allo-HCT for a hematological malignancy at three large academic institutions (n = 503; period 2008–2019). We used Cox proportional hazard and Fine–Gray competing risk models, martingale residual plots and maximally selected log-rank statistics to assess the impact of IR on outcomes. Achieving CD4 >50 and/or B cells >25 cells/μL before day 100 after allo-HCT was a predictor of lower NRM (CD4 IR: hazard ratio [HR] 0.26, 95% confidence interval [CI] 0.11–0.62, P = 0.002; CD4 and B cell IR: HR 0.06, 95% CI 0.03–0.16, P < 0.001), acute graft-versus-host disease (GVHD) (CD4 and B cell IR: HR 0.02, 95% CI 0.01–0.04, P < 0.001) and chronic GVHD (CD4 and B cell IR: HR 0.16, 95% CI 0.05–0.49, P = 0.001) in the full cohort, and of lower risk of relapse (CD4 and B cell IR: HR 0.24, 95% CI 0.06–0.92, P = 0.038) in the acute myeloid leukemia subgroup. No correlation between CD8 and NK-cell IR and relapse or NRM was found. CD4 and B-cell IR was associated with clinically significant lower NRM, GVHD and, in patients with acute myeloid leukemia, disease relapse. CD8 and NK-cell IR was neither associated with relapse nor NRM. If confirmed in other cohorts, these results can be easily implemented for risk stratification and clinical decision making. [Display omitted] [ABSTRACT FROM AUTHOR]

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is a clinically challenging modality for the treatment of many hematologic diseases such as leukemia, lymphoma, and myeloma. Graft-versus-host disease (GVHD) is a common complication after allo-HSCT and remains a major cause of morbidity and mortality, limiting the success of a potentially curative transplant. Several microRNAs (miRNAs) have recently been shown to impact the biology of GVHD. They are molecular regulators involved in numerous processes during T-cell development, homeostasis, and activation, and contribute to the pathological function of T-cells during GvHD. Here, we review the key role of miRNAs contributing to the GvHD; their detection might be an interesting possibility in the early diagnosis and monitoring of disease [ABSTRACT FROM AUTHOR]

Tyrosine kinase inhibitors (TKIs) have revolutionized the treatment of chronic myeloid leukemia (CML), granting patients a life expectancy close to that of the normal population and, in a subset of patients, the possibility to discontinue therapy. Nonetheless, for a not negligible minority of patients, TKIs are not able to control CML. Allogeneic hematopoietic cell transplantation (HCT) has long been a pivotal therapy for CML. At present, allogeneic HCT is considered an option in CML patients diagnosed or progressing to blast phase (BP), for those in chronic phase (CP) resistant to multiple lines of TKI therapy or for those experiencing severe toxicity, mostly hematologic, under TKIs. Moving from real-world cases, we reviewed the results of allogeneic HCT in the setting of advanced-phase CML or failure of TKIs, with a focus on the progresses in transplant technology that has extended transplant options in elderly CML patients and in those lacking a sibling donor, and on the post-HCT strategies for prevention and treatment of disease relapse. [ABSTRACT FROM AUTHOR]

• Increased naïve T-cells in the CD4 T-lymphocyte population. • Increased TEMRA (effector memory T-cells that re-express CD45RA) cells in the CD8 T-cell population. • Treg:Tcons and Treg:CD8 ratios in patients with chronic G v HD. • Impaired reconstitution of distinct CD4 and CD8 T-cell subsets and their imbalance with Tregs may be involved in developing acute and chronic G v HD. The reconstitution of different T-cell subsets following allogeneic hematopoietic stem cell transplantation (allo-HSCT) is critical for efficient pathogen protection and the prevention of graft-versus-host disease (G v HD). In particular, studies have highlighted the importance of balanced ratios of regulatory T-cells (Tregs) and distinct functionally T-cells in preventing acute and chronic G v HD. We evaluated the regeneration of CD4 and CD8 T-cell subpopulations in nine pediatric patients with non-malignant disorders following allo-HSCT from a fully HLA-identical donor. CD4 and CD8 T-cells were higher 12 months after the transplant but still lower than in healthy controls and pre-transplant. However, we found after allo-HSCT, central memory and effector memory cell subsets were the predominant phenotypes in the CD4 and CD8 T-cell populations, respectively. In patients who had developed acute G v HD, there was an increase in the frequency of TEMRA (effector memory T cells that re-express CD45RA) cells within the CD4 T-cell population. Meanwhile, in patients with chronic G v HD, we observed a decrease in Th1 cells in CD4 T-cells and effector memory cells within the CD8 T-cell population. In addition, we found decreased TEMRA cell subsets in CD4 and CD8 T-cell populations in chronic G v HD. Our findings suggest a possible relationship between the influence of acute G v HD and its prevention on delayed CD4 T-cell reconstitution and, reciprocally, unbalanced regeneration of CD4 and CD8 T-cell subsets in the development of chronic G v HD. [ABSTRACT FROM AUTHOR]

JAK inhibitors are important therapeutic options for hematological disorders, especially myeloproliferative neoplasms. Ruxolitinib, the first JAK inhibitor approved for clinical use, improves splenomegaly and ameliorates constitutional symptoms in both myelofibrosis and polycythemia vera patients. Ruxolitinib is also useful for controlling hematocrit levels in polycythemia vera patients who were inadequately controlled by conventional therapies. Furthermore, pretransplantation use of ruxolitinib may improve the outcome of allo-hematopoietic stem cell transplantation in myelofibrosis. In contrast to these clinical merits, evidence of the disease-modifying action of ruxolitinib, i.e., reduction of malignant clones or improvement of bone marrow pathological findings, is limited, and many myelofibrosis patients discontinued ruxolitinib due to adverse events or disease progression. To overcome these limitations of ruxolitinib, several new types of JAK inhibitors have been developed. Among them, fedratinib was proven to provide clinical merits even in patients who were resistant or intolerant to ruxolitinib. Pacritinib and momelotinib have shown merits for myelofibrosis patients with thrombocytopenia or anemia, respectively. In addition to treatment for myeloproliferative neoplasms, recent studies have demonstrated that JAK inhibitors are novel and attractive therapeutic options for corticosteroid-refractory acute as well as chronic graft versus host disease. [ABSTRACT FROM AUTHOR]

Introduction: The infusion of ex-vivo-generated regulatory B cells may represent a promising novel therapeutic approach for a variety of autoimmune and hyperinflammatory conditions including graft-versus-host disease. Methods: Previously, we developed a protocol for the generation of a novel population of regulatory B cells, which are characterized by secretion of enzymatically active granzyme B (GraB cells). This protocol uses recombinant interleukin 21 (IL-21) and goat-derived F(ab)’2 fragments against the human B cell receptor (anti-BCR). Generally, the use of xenogeneic material for the manufacturing of advanced therapy medicinal products should be avoided to prevent adverse immune reactions as well as potential transmission of so far unknown diseases. Results: In the present work we demonstrated that phorbol-12-myristate-13- acetate (PMA/TPA), a phorbol ester with a particular analogy to the second messenger diacylglycerol (DAG), is a potent enhancer of IL-21-induced differentiation of pre-activated B cells into GraB cells. The percentage of GraB cells after stimulation of pre-activated B cells with IL-21 and PMA/TPA was not significantly lower compared to stimulation with IL-21 and anti-BCR. Discussion: Given that PMA/TPA has already undergone encouraging clinical testing in patients with certain haematological diseases, our results suggest that PMA/TPA may be a safe and feasible alternative for ex-vivo manufacturing of GraB cells. [ABSTRACT FROM AUTHOR]

Objectives: Graft‐versus‐host disease (GVHD) is an important complication of bone marrow transplantation. Recent reports suggest the significance of T‐cell subsets (Th1, Th17, and cytotoxic CD8+ T cells) as well as CD163+ macrophages in the development of cutaneous GVHD. CD163+ macrophages produce various chemokines to establish the immunological microenvironment following stimulation by stromal factors in lesional skin. Thus, the purpose of this study is to determine the main source of IFN‐inducible chemokines in the lesional skin of GVHD. Methods: We employed immunohistochemical (IHC) staining for CD163 as well as interferon (IFN)‐inducible chemokines (CXCL9, CXCL10, CXCL11) to determine if the main source of IFN‐inducible chemokines in the lesional skin of GVHD was CD163+ macrophages. Moreover, we investigated the possible cytokine profiles of lesional skin in GVHD by evaluating phospho‐signal transducer and activator of transcription (pSTAT) expression in epidermal keratinocytes. Results: Immunohistochemical staining of serial sections for CD163 revealed that CXCL9‐expressing cells, CXCL10‐expressing cells, and CXCL11‐expressing cells were detected in adjacent to CD163+ TAMs in the dermis. In contrast, there were no CCL17‐expressing cells or CCL22‐expressing cells in the dermis. The nuclei of epidermal keratinocytes in GVHD expressed pSTAT1, pSTAT3, and pSTAT5B. Conclusions: The chemokine expression patterns on CD163+ macrophages matched the expected phosphorylation pattern of epidermal STATs. Our present study suggested that CD163 + macrophages may be a therapeutic target in GVHD. The significance of T‐cell subsets (Th1, Th17, and cytotoxic CD8+ T cells) as well as CD163+ macrophages in the development of cutaneous GVHD. ·IHC staining revealed that CXCL9‐expressing cells, CXCL10‐expressing cells, and CXCL11‐expressing cells were detected in adjacent to CD163+ TAMs in the dermis. ·The chemokine expression patterns on CD163+ macrophages matched the expected phosphorylation pattern of epidermal STATs. [ABSTRACT FROM AUTHOR]

Background: In allogeneic hematopoietic stem cell transplantation (HSCT), Anti-T-Lymphocyte Globulin (ATLG) may be used for the prevention of severe graft-versus-host disease (GVHD). ATLG targets both the recipient's lymphocytes and those transferred with the graft. Assuming an inverse relation between the recipient's absolute lymphocyte count (ALC) and exposure of remaining ATLG to the graft, we aim to evaluate the impact of the recipient's ALC before the first ATLG administration on the benefits (prevention of GVHD and GVHD-associated mortality) and potential risks (increased relapse incidence) associated with ATLG. Methods: In recipients of HLA-matched, ATLG-based HSCT (n = 311), we assessed the incidence of acute GVHD, GVHD-related mortality and relapse, as well as other transplant-related outcomes, in relation to the respective ALC (divided into tertiles) before ATLG. Results: The top-tertile ALC group had a significantly increased risk of aGVHD (subhazard ratio (sHR) 1.81; [CI 95%; 1.14–2.88]; p = 0.01) and aGVHD-associated mortality (sHR 1.81; [CI 95%; 1.03–3.19]; p = 0.04). At the highest ATLG dose level (≥45 mg/kg), recipients with lowest-tertile ALC had a trend towards increased relapse incidence (sHR 4.19; [CI 95%; 0.99–17.7]; p = 0.05, n = 32). Conclusions: ATLG dosing based on the recipient's ALC may be required for an optimal balance between GVHD suppression and relapse prevention. [ABSTRACT FROM AUTHOR]

Transcription factors play a major role in regulation and orchestration of immune responses. The immunological context of the response can alter the regulatory networks required for proper functioning. While these networks have been well-studied in canonical immune contexts like infection, the transcription factor landscape during alloactivation remains unclear. This review addresses how transcription factors contribute to the functioning of mature alloactivated T cells. This review will also examine how these factors form a regulatory network to control alloresponses, with a focus specifically on those factors expressed by and controlling activity of T cells of the various subsets involved in graft-versus-host disease (GVHD) and graft-versus-tumor (GVT) responses. [ABSTRACT FROM AUTHOR]

Graft versus host disease (GVHD) is one of the most serious complications following stem cell transplant in children and is a major cause of morbidity and mortality. Corticosteroids remain the mainstay of treatment, and although a majority of children respond to systemic steroids, those refractory to or dependent upon corticosteroids suffer from complications secondary to long-term steroid administration. This problem has prompted consideration of steroid-sparing treatment strategies, although the time to clinical remission can be variable. Intraarterial corticosteroid delivery has been used in adults as a rescue therapy in steroid-resistant patients, but its use in children has been limited. We investigated the feasibility of intraarterial steroid administration into the bowel and/or liver in a cohort of six pediatric patients with acute GVHD. All patients successfully underwent treatment with no serious adverse effects. Five of five (100%) patients with gastrointestinal bleeding due to GVHD had rapid symptom improvement by 48 h, which was durable up to three weeks. Three of four (75%) patients with hepatic GVHD had improved cholestasis following intraarterial steroid administration. Our experience with this small cohort preliminarily demonstrated the feasibility and safety of intraarterial steroid administration in children with acute GVHD. This approach warrants consideration as a rescue therapy in steroid-refractory cases and as a "bridge" therapy for children with severe acute GVHD who are transitioning to steroid-sparing regimens. [ABSTRACT FROM AUTHOR]

Short tandem repeat (STR) analysis to assess chimerism is a critical aspect of routine care particularly in patients facing stem cell transplants but is also relevant in other clinical scenarios. STR analysis provides a means to assess donor and recipient cellular origins in a patient, and, as such, can inform engraftment, rejection, and relapse status in stem cell transplant recipients. In this review of STR testing, the most commonly used method to assess chimerism, its background, procedural details, and clinical utility are discussed. [ABSTRACT FROM AUTHOR]

Allogeneic hematopoietic stem cell transplantation is a definitive therapy for a variety of disorders. One of the complications is acute graft-versus-host disease (aGVHD), which has a high mortality rate. Patients can also develop chronic graft-versus-host disease (cGVHD), a more indolent yet afflicting condition that affects up to 70% of patients. Ocular involvement (oGVHD) is one of the most prevalent presentations of cGVHD and can manifest as dry eye disease, meibomian gland dysfunction, keratitis, and conjunctivitis. Early recognition of ocular involvement using regular clinical assessments as well as robust biomarkers can aid in better management and prevention. Currently, the therapeutic strategies for the management of cGVHD, and oGVHD in particular, have mainly focused on the control of symptoms. There is an unmet need for translating the preclinical and molecular understandings of oGVHD into clinical practice. Herein, we have comprehensively reviewed the pathophysiology, pathologic features, and clinical characteristics of oGVHD and summarized the therapeutic landscape available to combat it. We also discuss the direction of future research regarding a more directed delineation of pathophysiologic underpinnings of oGVHD and the development of preventive interventions. [ABSTRACT FROM AUTHOR]

Abstract Due to relatively high nonrelapse mortality (NRM), allogeneic hematopoietic stem cell transplantation (allo‐HSCT) in non‐Hodgkin's lymphoma (NHL) remains the ultimate line of treatment but the only curable approach in a setting of relapse/refractory disease. Here, we conducted a retrospective, multicenter, registry‐based analysis on patients who underwent allo‐HSCT for NHL in Switzerland, over 30‐year (1985–2020) period. The study included 301 allo‐HSCTs performed for NHL patients in three University Hospitals of Switzerland (Zurich, Basel and Geneva) 09/1985 to 05/2020. We assessed in univariate and multivariable analysis the impact on survivals (overall survival [OS], relapse free survival [RFS], relapse incidence [RI], and non‐treatment related mortality [NRM]). The maximum follow‐up was 25 years with median follow‐up for alive patients of 61 months. The median age at allo‐HSCT was 51 years. Three‐ and ‐year OS was ‐ 59.5% and 55.4%; 3‐ and 5‐year PFS was 50% and 44%; 3‐ and 5‐year NRM was 21.7% and 23.6%. RI at 3 and 5 years was 27.4% and 34.9%. In conclusion, our analysis of the entire Swiss experience of allo‐HSCT in patients with NHL shows promising 5‐ and possibly 10‐year OS and relatively acceptable NRM rates for such population, the majority being not in complete remission (CR) at the time of transplantation.

On behalf of Cell Therapy Transplant Canada (CTTC), we are pleased to present the Abstracts of the CTTC 2022 Annual Conference. The conference was held in-person 15–18 June 2022, in Niagara Falls, Ontario. Poster authors presented their work during a lively and engaging welcome reception on Thursday, 16 June, and oral abstract authors were featured during the oral abstract session in the afternoon on Friday, 17 June 2022. Thirty-three (33) abstracts were selected for presentation as posters and six (6) as oral presentations. The top abstracts in each of four (4) categories, (1) Basic/Translational sciences, (2) Clinical Trials/Observations, (3) Laboratory/Quality, and (4) Pharmacy/Nursing/Other Transplant Support, received awards for both the oral and poster presentations. All of these were marked as “Award Recipient” with the relevant category. We congratulate all the presenters on their research and contribution to the field.

Foxp3 is regarded as the major transcription factor for T regulatory (Treg) cells and expression of Foxp3 is used to identify and quantitate Treg cells in mouse models. However, several studies have demonstrated that human CD4+ T conventional (Tconv) cells activated in vitro by T cell receptor (TCR) stimulation can express Foxp3. This observation has raised doubt as to the suitability of Foxp3 as a Treg marker in man. Helios, a member of the Ikaros gene family, has been shown to be expressed by 80-90% of human Foxp3+ Treg cells and can potentially serve as a marker of human Treg. Here, we confirm that Foxp3 expression is readily upregulated by Tconv upon TCR stimulation in vitro, while Helios expression is not altered. More importantly, we show that Foxp3 expression is not elevated by stimulation of hTconv in a humanized mouse model of graft versus host disease (GVHD) and in patients with a wide variety of acute and chronic inflammatory diseases including sickle cell disease, acute and chronic GVHD, systemic lupus erythematosus, as well as critical COVID-19. In all patients studied, an excellent correlation was observed between the percentage of CD4+ T cells expressing Foxp3 and the percentage expressing Helios. Taken together, these studies demonstrate that Foxp3 is not induced upon Tconv cell activation in vivo and that Foxp3 expression alone can be used to quantitate Treg cells in humans. Nevertheless, the combined use of Foxp3 and Helios expression provides a more reliable approach for the characterization of Treg in humans. [ABSTRACT FROM AUTHOR]

The field of epigenetics studies the complex processes that regulate gene expression without altering the DNA sequence itself. It is well established that epigenetic modifications are crucial to cellular homeostasis and differentiation and play a vital role in hematopoiesis and immunity. Epigenetic marks can be mitotically and/or meiotically heritable upon cell division, forming the basis of cellular memory, and have the potential to be reversed between cellular fate transitions. Hence, over the past decade, there has been increasing interest in the role that epigenetic modifications may have on the outcomes of allogeneic hematopoietic transplantation and growing enthusiasm in the therapeutic potential these pathways may hold. In this brief review, we provide a basic overview of the types of epigenetic modifications and their biological functions, summarizing the current literature with a focus on hematopoiesis and immunity specifically in the context of allogeneic hematopoietic stem cell transplantation. [ABSTRACT FROM AUTHOR]

Cancer immunotherapy relies on improving T cell effector functions against malignancies, but despite the identification of several key transcription factors (TFs), the biological functions of these TFs are not entirely understood. We developed and utilized a novel, clinically relevant murine model to dissect the functional properties of crucial T cell transcription factors during anti-tumor responses. Our data showed that the loss of TCF-1 in CD8 T cells also leads to loss of key stimulatory molecules such as CD28. Our data showed that TCF-1 suppresses surface NKG2D expression on naïve and activated CD8 T cells via key transcriptional factors Eomes and T-bet. Using both in vitro and in vivo models, we uncovered how TCF-1 regulates critical molecules responsible for peripheral CD8 T cell effector functions. Finally, our unique genetic and molecular approaches suggested that TCF-1 also differentially regulates essential kinases. These kinases, including LCK, LAT, ITK, PLC-γ1, P65, ERKI/II, and JAK/STATs, are required for peripheral CD8 T cell persistent function during alloimmunity. Overall, our molecular and bioinformatics data demonstrate the mechanism by which TCF-1 modulated several critical aspects of T cell function during CD8 T cell response to cancer. Summary Figure: TCF-1 is required for persistent function of CD8 T cells but dispensable for anti-tumor response. Here, we have utilized a novel mouse model that lacks TCF-1 specifically on CD8 T cells for an allogeneic transplant model. We uncovered a molecular mechanism of how TCF-1 regulates key signaling pathways at both transcriptomic and protein levels. These key molecules included LCK, LAT, ITK, PLC-γ1, p65, ERK I/II, and JAK/STAT signaling. Next, we showed that the lack of TCF-1 impacted phenotype, proinflammatory cytokine production, chemokine expression, and T cell activation. We provided clinical evidence for how these changes impact GVHD target organs (skin, small intestine, and liver). Finally, we provided evidence that TCF-1 regulates NKG2D expression on mouse naïve and activated CD8 T cells. We have shown that CD8 T cells from TCF-1 cKO mice mediate cytolytic functions via NKG2D. [ABSTRACT FROM AUTHOR]

Hematopoietic stem cell transplantation (HSCT) results in profound immunosuppression for the first few months after the procedure, requiring patients to be revaccinated against childhood vaccine-preventable infectious diseases. Patients who undergo allo-HSCT are at high risk of bacterial, fungal, and viral infections, with infectious complications responsible for at least one third of deaths. Even before the COVID-19 pandemic, respiratory virus infections were known to be more severe in HSCT recipients. The pandemic has highlighted the vulnerability of HSCT recipients, who experience an increased risk of morbidity and mortality after COVID-19 compared with healthy populations due to their severe immunodeficiency status. However, the current pandemic has also provided an exceptional scenario to better understand the immune response to SARS-CoV-2 cases and mRNA vaccines in HSCT recipients, including those receiving CD19-directed chimeric antigen receptor T cell (CAR-T) therapy. Researchers have focused on the role of the immune system in protecting against severe SARS-CoV-2 in patients with hematologic malignancies, including HSCT recipients. Insights gained during the pandemic will likely soon be used to improve preventive strategies in this population against viral infections in the near future. This narrative review summarizes the current knowledge on SARS-CoV-2 immunity in HSCT and cell therapy recipients following SARS-CoV-2 cases or vaccination. [ABSTRACT FROM AUTHOR]

Anti-thymocyte globulin (ATG) is widely used to reduce acute and chronic graft-versus-host disease (a/cGVHD), one of the leading causes of morbidity and mortality after allogeneic hematopoietic stem cell transplantation (HSCT). As the removal of alloreactive T cells by ATG may also reduce the graft-versus-leukemia effect, the question of whether ATG use affects relapse incidence and survival outcomes in acute leukemia patients with pre-transplant bone marrow residual blasts (PRB) remains controversial. Here, we evaluated the impact of ATG on transplant outcomes in acute leukemia patients with PRB (n = 994) who underwent HSCT from HLA 1-allele mismatched unrelated donors (MMUD) or HLA 1-antigen mismatched related donors (MMRD). In MMUD with PRB (n = 560), multivariate analysis demonstrated that ATG use significantly decreased grade II–IV aGVHD (hazard ratio [HR], 0.474; P = 0.007) and non-relapse mortality (HR, 0.414; P = 0.029) and marginally improved extensive cGVHD (HR, 0.321; P = 0.054) and GVHD-free/relapse-free survival (HR, 0.750; P = 0.069). We concluded that ATG had different effects on transplant outcomes using MMRD and MMUD, and its use would be beneficial to decrease a/cGVHD without increasing non-relapse mortality and relapse incidence in acute leukemia patients with PRB following HSCT from MMUD. [ABSTRACT FROM AUTHOR]

In recent years, with the gradual advancement of haploidentical transplantation technology, the availability of donors has increased significantly, along with the widespread use of reduced-intensity conditioning and the improvement of nursing techniques, giving more elderly acute myeloid leukemia (AML) patients the chance to receive allogeneic hematopoietic stem cell transplantation. We have summarized the classic and recently proposed pre-transplant assessment methods and assessed the various sources of donors, conditioning regimens, and post-transplant complication management based on the outcomes of largescale clinical studies for elderly AML patients. [ABSTRACT FROM AUTHOR]

Summary: Acute graft‐versus‐host disease (aGVHD) is a life‐threatening complication after allogeneic haematopoietic cell transplantation, with gastrointestinal (GI) tract involvement (GI aGVHD) being one of the leading causes of morbidity and mortality. Whilst systemic steroids are the standard first‐line treatment for aGVHD, approximately 50% of patients become steroid refractory (SR), which is associated with poor outcomes. Existing options for SR‐GVHD are limited, and there is a significant unmet need for new non‐immunosuppressive treatment approaches in patients with GI aGVHD. Here, we review newer concepts in the pathogenesis of GI aGVHD and present the evidence for the role of glucagon‐like peptide 2 (GLP‐2) in maintaining and protecting GI epithelial cells, including the enterocytes, intestinal stem cells and Paneth cells, which are direct targets of aGVHD. Finally, we discuss the therapeutic rationale for GLP‐2 treatment as a tissue regeneration approach and the potential use of the novel GLP‐2 analogue apraglutide as an adjunctive treatment for GI aGVHD. [ABSTRACT FROM AUTHOR]

Systemic steroids are still the first-line approach in acute graft-versus-host disease (aGvHD), and the backbone of chronic GvHD management. Refractoriness to steroid represent a major cause of morbidity and non-relapse mortality after hematopoietic stem cell transplantation (HSCT). In both backgrounds, several second-line immunosuppressive agents have been tested with variable results in terms of efficacy and toxicity. Solid evidence regarding these approaches is still lacking in the pediatric setting where results are mainly derived from adult experiences. Furthermore, the number of treated patients is limited and the incidence of acute and chronic GvHD is lower, resulting in a very heterogeneous approach to this complication by pediatric hematologists. Some conventional therapies and anti-cytokine monoclonal antibodies used in the adult setting have been evaluated in children. In recent years, the increasing understanding of the biological mechanisms underpinning the pathogenesis of GvHD justified the efforts toward the adoption of targeted therapies and non-pharmacologic approaches, with higher response rates and lower immunosuppressive effects. Moreover, many questions regarding the precise timing and setting in which to integrate these new approaches remain unanswered. This Review aims to critically explore the current evidence regarding novel approaches to treat SR-GvHD in pediatric HSCT recipients.

BackgroundMethotrexate (MTX), utilized as a graft-versus-host disease (GvHD) prophylactic agent in allogeneic hematopoietic stem cell transplantation (allo-HSCT), has been proven to effectively decrease the occurrence of the peri-engraftment syndrome (Peri-ES) and acute GvHD (aGvHD). Changes in the pharmacodynamics of MTX are closely associated with gene polymorphisms in genes encoding drug-metabolizing enzymes and transporters. Nevertheless, the current studies mainly concentrate on leukemia or autoimmune diseases, and limited studies on allo-HSCT were reported.MethodsHere, we retrospectively assessed the relationship between MTX-related transporter and metabolizing enzyme gene polymorphisms, clinical characteristics, and outcomes in 57 pediatric patients who received haploid HSCT (haplo-HSCT) with malignant tumors at a single center.ResultsWe discovered all gene polymorphisms were in the Hardy–Weinberg equilibrium in our cohort. We discovered a significant correlation between platelet recovery time and ABCB1 (1236C>T) (p = 0.042). Compared with patients with SLCO1B1 (1865+4846T>C) TT, patients with SLCO1B1 (1865+4846T>C) TC/CC had an increased incidence of Peri-ES (p = 0.030). Based on the multivariate Cox analysis, we discovered that SLCO1B1 (1865+4846T>C) TT genotype was an independent protective factor for Peri-ES morbidity (hazard ratio (HR) = 0.464, p = 0.031), and the dose of mononuclear cells reinfused was significantly correlated with II–IV aGvHD (HR = 2.604, p = 0.039).ConclusionIn summary, our findings prove that the host’s genotypes might modify the risk of developing Peri-ES, contribute to a better understanding of the inter-individual difference in efficacy, and facilitate the development of individualized approaches to GvHD prophylaxis.

Acute graft-versus-host disease (GvHD) remains the biggest clinical challenge and prognosis-determining complication after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Donor T cells are acceptedly key mediators of alloreactivity against host tissues and here especially the gut. In support of previous studies, we found that the intestinal intra-epithelial lymphocyte (IEL) compartment was dynamically regulated in the course of MHC class I full mismatch allo-HSCT. However, while intestinal epithelial cell (IEC) damage endangers the integrity of the intestinal barrier and is a core signature of intestinal GvHD, the question whether and to what degree IELs are contributing to IEC dysregulation is poorly understood. To study lymphoepithelial interaction, we employed a novel ex vivo T cell/organoid co-culture model system. Here, allogeneic intra-epithelial T cells were superior in inducing IEC death compared to syngeneic IEL and allogeneic non-IEL T cells. The ability to induce IEC death was predominately confined to TCRβ+ T cells and was executed in a largely IFNγ-dependent manner. Alloreactivity required a diverse T cell receptor (TCR) repertoire since IELs genetically modified to express a TCR restricted to a single, non-endogenous antigen failed to mediate IEC pathology. Interestingly, minor histocompatibility antigen (miHA) mismatch was sufficient to elicit IEL-driven IEC damage. Finally, advanced live cell imaging analyses uncovered that alloreactive IELs patrolled smaller areas within intestinal organoids compared to syngeneic controls, indicating their unique migratory properties within allogeneic IECs. Together, we provide here experimental evidence for the utility of a co-culture system to model the cellular and molecular characteristics of the crosstalk between IELs and IEC in an allogeneic setting ex vivo. In the light of the emerging concept of dysregulated immune-epithelial homeostasis as a core aspect of intestinal GvHD, this approach represents a novel experimental system to e.g. screen therapeutic strategies for their potential to normalize T cell/IEC- interaction. Hence, analyses in pre-clinical in vivo allo-HSCT model systems may be restricted to hereby positively selected, promising approaches.

Introduction: Cytomegalovirus (CMV) infection is a major clinical issue after allogeneic hematopoietic stem cell transplantation (HSCT). The CMV envelope glycoproteins are key in viral pathogenesis; the glycoprotein B (gB) encoded by the UL55 gene might be an important determinant of viral virulence and disease severity marker in patients treated with allogeneic HSCT. Our aim was to investigate the molecular diversity of CMV gB and inquire into the associations between UL55 gene variations and clinical manifestations in adult patients treated with allogeneic HSCT. Results: The most prevalent genotypes were gB1 and gB4 (11/27, 40.7%). Patients with genotype gB1 infection had earlier platelet engraftment (p < 0.033) and less frequent minimal/measurable residual disease post HSCT than those without this genotype. Patients with gB4 glycoprotein infection had a significantly lower CD4+/CD8+ ratio at D90 (p < 0.026). Interestingly, patients with gB5 glycoprotein infection had shorter overall survival from base condition diagnosis (p < 0.042), as well as shorter overall survival after HSCT (p < 0.036). Acute GvHD was noted more frequently in those with mixed-genotype infection (p = 0.047). Material and Methods: The study included fifty-nine adult patients treated with allogeneic HSCT. Peripheral venous blood was sampled typically per week, with detection of CMV performed by quantitative real-time PCR. Multiplex nested PCR was used to determine specific gB genotypes, which were then statistically compared vis-à-vis specific clinical variables. Conclusions: Our study points to variations in the viral UL55 locus imparting both beneficial (earlier platelet engraftment, less frequent MRD post HSCT) and adverse effects (shorter overall survival, more frequent acute GvHD, less frequent 100% chimerism at day 90) to the transplanted host. Comprehensive molecular investigations are necessary to validate this apparent duality, as the potential benefits of CMV could perhaps be utilized for the benefit of the patient in the future.

A crucial complication after allogeneic hematopoietic cell transplantation (alloHCT), namely, acute graft-versus-host disease (aGVHD), occurs in about 50% of transplant recipients, leading to high morbidity and mortality. Thus far, the diagnosis of GVHD has been mainly established through clinical features and histologic or laboratory evidence of periductal lymphocyte infiltration, fibroplasia, and mixed lymphocytic and plasmocytic inflammation. Intensive research is focused on identifying biomarkers for the early diagnosis, prediction of disease, response to treatment, prognosis, and risk stratification of patients. The serum biomolecules that have been investigated are reported and summarized. Moreover, oral tissue involvement in GVHD is described, and other biomarkers that have been proposed, such as saliva, are analyzed. Future research is highlighted as a necessity in order for these biomarkers to be validated and quantified for use in clinical practice.

GvHD still remains, despite the continuous improvement of transplantation platforms, a fearful complication of transplantation from allogeneic donors. Being able to separate GvHD from GvL represents the greatest challenge in the allogeneic transplant setting. This may be possible through continuous improvement of cell therapy techniques. In this review, current cell therapies are taken into consideration, which are based on the use of TCR alpha/beta depletion, CD45RA depletion, T regulatory cell enrichment, NK-cell-based immunotherapies, and suicide gene therapies in order to prevent GvHD and maximally amplify the GvL effect in the setting of haploidentical transplantation.

Transcription factors play a major role in regulation and orchestration of immune responses. The immunological context of the response can alter the regulatory networks required for proper functioning. While these networks have been well-studied in canonical immune contexts like infection, the transcription factor landscape during alloactivation remains unclear. This review addresses how transcription factors contribute to the functioning of mature alloactivated T cells. This review will also examine how these factors form a regulatory network to control alloresponses, with a focus specifically on those factors expressed by and controlling activity of T cells of the various subsets involved in graft-versus-host disease (GVHD) and graft-versus-tumor (GVT) responses.