Pathogenic CD4+ memory T cells (Tm) sustain chronic inflammation, but mechanisms remain undefined. Here, we identify four donor-type CD4+ Tm subsets in the target tissues of autoimmune-like chronic graft-versus-host disease in mice: Ly108+CD69- stem-like memory T cells (Tsm), Ly108+CD69+ resident memory progenitor T cells (Trmp), Ly108-CD69+ terminally differentiated tissue-resident T cells (Trm), and Ly108-CD69- intermediate T cells (Tint). Trm are terminally differentiated but not exhausted and show highly biased clonotypes with high proinflammatory cytokine expression. Tsm cells require TCR-MHCII interactions for their maintenance and expansion and show greater capacity than Trmp cells in self-renewal/expansion, generation of Trm, and pathogenicity in adoptive recipients. The transcription factors TCF1/BCL6 and BHLHE40 differentially regulate the stemness and differentiation of Tsm into Trm, respectively, and their selective targeting reduces the number of Trm in tissues and ameliorates inflammation. Thus, our findings indicate that targeting the Tsm subset, involved in the maintenance of the pathogenic Tm pool, offers an attractive approach to treat T cell-mediated chronic inflammation.

Introduction: In preparing for our Clinical and Translational Science Award (CTSA) UM1 application, we recognized the need to develop a shared understanding of the distinctions between translational science (TS) and translational research (TR). We describe our efforts to develop and evaluate the reliability of a concise instrument that investigators and reviewers could use to distinguish between TS and TR.Methods: Groups of faculty and staff individually reviewed published translational studies to determine whether the project involved TS and, separately, TR. One group (n = 10) first reviewed 14 publications with limited guidance; the same group and a second group (n = 9) then reviewed another set of 14 publications guided by a detailed algorithm. We used kappa statistics to measure agreement in the determinations of TS and TR for each publication.Results: The overall kappa coefficients in the three sets of TS determinations (two by the first group and one by the second group) were 0.61, 0.33, and 0.18, respectively. The overall kappa coefficients in the three sets of TR determinations were 0.26, 0.11, and 0.40, respectively. The median kappa coefficients for all 42 determinations were 0.39 for TS and 0.22 for TR, both indicating only fair agreement. We found no evidence that the algorithm helped to improve agreement rates.Conclusion: Our results show gaps in understanding the distinction between TS and TR among CTSA hub faculty and staff. We discuss some reasons for this gap and propose ways that could improve the recognition of TS and TR.

While the incidence of chronic Graft-versus-Host Disease (chronic GVHD) is declining due to advances in prophylaxis and survival is improving due to better supportive care, first-line treatment of chronic GVHD continues to be based on corticosteroids. Numerous attempts to establish more effective or less toxic treatment alternatives have largely failed, likely due to the biological heterogeneity of chronic GVHD and uncontrolled use of systemic corticosteroids, indicating the need for new approaches. The 2020 NIH consensus conference proposed the systematic evaluation of steroid-free initial treatment combining clinical and biological assessment to establish personalized approaches. While the first generation of trials evaluating steroid-free single agent first-line therapy approaches are recruiting, they are still not able to consider the biological heterogeneity of chronic GVHD in deciding therapeutic approaches. To advance the field, we propose a two-stage adaptive trial design starting with an intervention under consideration followed by a replication phase after the first phase has identified candidate clinical features and or biomarker predicting success. For second and subsequent lines of treatment, current treatment decisions regarding the use of the four FDA approved agents are based on the product label or a trial-and-error approach, sometimes in combination regimens despite the lack of prospective data. Future trials and prospective observational studies should focus on the development of predictive markers to provide a biological rationale for sequencing treatment options and to identify synergistic combination treatments. The recently released FDA draft guidance document for developing drugs and treatments in GVHD serves as the starting point for clinical trials planning that should yield results during the next several years.

Steroid-refractory gut acute graft-versus-host disease (SR-Gut-aGVHD) is the major cause of nonrelapse death after allogeneic hematopoietic cell transplantation. High numbers of donor-type IL-22+ T cells, IL-22-dependent dysbiosis, and loss of antiinflammatory CX3CR1hi mononuclear phagocytes (MNPs) play critical roles in SR-Gut-aGVHD pathogenesis. CEACAM1 on intestinal epithelial cells (IECs) is proposed to regulate bacterial translocation and subsequent immune responses in the intestine. Here, with imaging mass cytometry (IMC), combined scRNA-Seq with ATAC-Seq, and high-dimensional flow cytometry analysis, we show that CEACAM1 expression was enhanced on IECs in murine and human SR-Gut-aGVHD. Ceacam1 deficiency on host IECs effectively prevented SR-Gut-aGVHD in murine models. Ceacam1 deficiency on IECs resulted in (i) higher numbers of IL-22+IL-10+Foxp3+CD4+ peripheral Tregs (pTregs) and lower numbers of conventional IL-22+CD4+ T (Tcon), Th/Tc1, and Th17 cells in the intestine; (ii) higher prevalence of beneficial commensal bacteria that augment colonic pTreg expansion, with lower prevalence of pathogenic bacteria; and (iii) higher numbers of antiinflammatory CD103-CX3CR1hi MNPs that produce indoleamine 2,3-dioxygenase (IDO) and IL-10, with lower numbers of proinflammatory CD103+CX3CR1lo MNPs that produce IL-6. Thus, specifically targeting IEC CEACAM1 represents a promising approach for prevention of SR-Gut-aGVHD.

Chronic graft-versus-host disease (GVHD) occurs in 30–70% of patients after allogeneic hematopoietic cell transplantation (HCT) and increases the risks of morbidity and mortality. Systemic corticosteroids are the standard initial treatment, but one-third of patients require subsequent treatment with other systemic agents. Treatment decisions are often based on physicians’ experience. The expected treatment response rates in specific organs affected by chronic GVHD may inform such decisions. In this review, we identify 20 studies reporting treatment response rates in individual organs according to objective criteria, summarize the results, discuss the caveats in data interpretation, identify the unmet needs, and suggest future directions in the field. For cutaneous sclerosis, we observed large discrepancies in organ response rates according to the current NIH criteria and patient-reported improvement, highlighting the need for better measurement tools. High response rates for lung involvement with certain novel drugs deserve further investigation.

Objectives/Goals: We aim to establish a systematic approach to distinguish translational science from translational research. Our goal is to create a simple tool that would enable individuals with different backgrounds and levels of expertise to readily determine whether a study truly features translational science. Methods/Study Population: Participants were recruited from a Clinical and Translational Science Award (CTSA) program hub and randomly divided into 2 groups. One group was asked, with minimal guidance, to categorize whether publications described translational science or translational research. The group met to resolve disagreements and identify key indicators and challenges in determining whether a study involves translational science. They provided input on a set of guiding questions intended to facilitate the identification of translational science. The second group did not participate in discussion or tool development. Both groups reviewed a new set of publications, using the tool to guide their assessments. Results/Anticipated Results: Based on publication assessments, we will assess the percent agreement among reviewers in each group for each publication and across the set. We anticipate that the first group will exhibit higher agreement for its second round of review than its first, owing to the benefit of discussion with colleagues and provision of guiding questions. We anticipate that the tool will also promote higher agreement among the second group in their first round of review. We predict that both groups will exhibit high rates of agreement when reviewing with the support of guiding questions. Discussion/Significance of Impact: This study will help us understand interpretations of translational science, a term that has sparked debate and disagreement within CTSA hubs. If successful, the guiding questions will provide CTSAs a tool to improve training, proposal responsiveness, and review for translational science projects.

Background: Results from randomized trials suggest that prophylaxis with anti-T lymphocyte globulin (ATLG) decreased the incidence of chronic graft-versus-host disease (cGVHD) without adversely impacting progression-free (PFS) or overall survival (OS). However, one prospective double blind randomized trial (NCT01295710) in adult recipients of a myeloablative 8/8 HLA matched unrelated donor grafts for acute leukemia or myelodysplastic syndromes who received ATLG with standard GVHD prophylaxis (tacrolimus and methotrexate), that was performed predominantly in the United States, had differing results. Despite significant reductions in grades 2-4 acute and chronic GVHD, there was inferior PFS and OS at 2 years in ATLG recipients. Moderate to severe cGVHD free survival was similar between study arms. The overall aim of this study was to determine the long-term clinical outcomes of patients treated on this trial based on data reported to the Center for International Blood and Marrow Transplant Research (CIBMTR). Methods: CIBMTR contacted US clinical trial centers, and, for those centers agreeing to participate, requested the patient CIBMTR Research ID, drug received (placebo or ATLG), and date of diagnosis of moderate-to-severe cGVHD. Fisher's exact test was used to compare categorical variables, Kruskal-Wallis for the continuous variable (age), Kaplan-Meier method for survival estimates, and the log-rank test for group comparisons of survival distributions and point estimates. Multivariate analyses were performed using the Cox proportional hazards model with ATLG as the main effect. The threshold for clinical significance was set at .05. Results: The study population comprised 217 (85.4%) of the 254 initially randomized clinical trial patients, including 108/128 (84.3%) in the placebo arm and 109/126 (86.5%) in the ATLG arm. Median follow-up was 98.8 months (range 27.7-125.6) in the placebo cohort and 97.9 months (range 16.1-125.3) in the ATLG cohort. As in the clinical trial, there were no differences in baseline characteristics between groups except for more males in the placebo group (65.7% vs 46.8%, P = .0061). 93% of patients in both groups identified as White. 4.6% and 3.7% identified as Hispanic in the placebo and ATLG cohorts, respectively. Univariate analysis revealed the probability of moderate-to-severe-cGVHD-free survival was similar between the groups (P = .421) The 2-year probabilities were 41.1% (95% CI, 31.9-50.6) in the placebo group and 46.1% (95% CI, 36.8-55.6) in the ATLG group. The probabilities decreased in both groups over time, being 24.5% (95% CI, 16.4-33.6) at 7 yrs in the placebo group and 33.3% (95% CI, 24.5-42.8) at 7 yrs in the ATLG group (P = .173). There was no difference between the groups at any time point. At 7 yrs after transplant, the probability of OS was similar between the placebo and ATLG groups (P = .290). OS at 2 yrs after transplant was 70.4% (95% CI, 61.4-78.6) in the placebo group and 60.5% (95% CI, 51.2-69.4) in the ATLG group. The probabilities decreased in both groups over time, being 50.4% (95% CI, 40.8-60.0) at 7 yrs in the placebo group and 46.6% (95% CI, 37.1-56.2) at 7 yrs in the ATLG group (P =.584). There was no difference between the groups at any time point. The probability of PFS was similar between the placebo and ATLG groups (P = .146) While PFS at 2 and 3 yrs after transplant was inferior in the ATLG group (P = .010), by 7 yrs the probability of PFS was 44.8% (95% CI, 35.3-54.5) in the placebo group, and 40% (95% CI, 30.9-49.3) in the ATLG group. Disease recurrence was the most common cause of death, 49.2% in the ATLG group and 36.2% in the placebo group. GVHD accounted for 3.2% of deaths in the ATLG group and 12.1% of deaths in the placebo group. In multivariate analysis, prophylaxis with ATLG did not impact moderate-to-severe cGVHD-free survival. (HR 0.644, 95% CI, 0.644-1.242; P = .5068), OS (HR 1.235, 95% CI, 0.857-1.781); P =.2573) or PFS (HR 1.386, 95% CI, 0.974-1.972); P = .07). Conclusions: This study conducted by the CIBMTR extends the findings of the phase 3 randomized trial clinical trial previously reported. As in the clinical trial, no significant difference was found in moderate to severe cGVHD free survival between the placebo and ATLG groups up to 7 years. In contrast to the clinical trial in which OS and PFS were lower in the ATLG group at 2 years, we found no significant long term differences in OS and PFS up to 7 years after transplant.

Cutaneous chronic graft versus host disease (cGVHD) is the major clinical manifestation of cGVHD patients. Tissue-resident memory T (Trm) cells and TCF1+ T progenitors locally in GVHD target tissues play important roles in maintaining GVHD. However, the mechanisms regulating TCF1+ progenitor differentiation into Trm in the skin remain largely unknown. In the current studies, with cGVHD murine models (C57BL/6 donors and BABL/c recipients) and humanized models of human HLA-A2-DR4- PBMC to MHC-/-HLA-A2+DR4+ NSG mice, we observed with flow cytometry analysis that most (>90%) of the injected donor CD4+ T cells in the skin tissues were CD69+ Trm, and the TCF1+ progenitors were less than 4%, which was markedly lower than in the liver and lung (>20%). The majority of Trm cells in the cGVHD skin were CD103+CXCR6+Foxp3- conventional CD4+ T cells that produce large amount of pro-inflammatory IFN-γ and GM-CSF, while CD103+ Trm cells in the skin of non-GVHD recipients were mostly Foxp3+ Treg cells. Genetic deficiency of T-bet, BHLHE40, STAT3 or BATF in the injected donor T cells markedly ameliorated skin cGVHD, all associated with lower numbers of CD103+ Trm cells and lower production of IFN-g/GM-CSF. Results were similar when skin cGVHD was greatly reduced by post-transplantation treatment with cyclophosphamide (PTCY) in murine models. In addition, scRNA-seq analysis of blood and skin T cells from GVHD patients in a public dataset showed that ~90% blood T cells express stemness related marker Tcf7 and large proportions of skin T cells (>95%) express terminally differentiated markers such as Cxcr6. Taken together, our results suggest that the differentiation of TCF1+ T progenitor cells into Trm cells in the skin is regulated by the T-bet/BHLHE40 axis and the TCR/STAT3/BATF axis. Although Trm cells are differentiated from TCF1+ T progenitor cells in the skin, the TCF1+ T progenitor cells in blood may play an important role in replenishing TCF1+ T progenitor cells in cGVHD target tissues.

Agents historically used to prevent graft-versus-host disease (GVHD) after allogeneic hematopoietic cell transplant (HCT) have typically targeted T cells.In this issue of Blood, Magenau et al 1 show that agents targeting antigenpresenting cells can also help prevent GVHD.

Letermovir is a relatively new antiviral for prophylaxis against cytomegalovirus (CMV) after allogeneic hematopoietic cell transplantation (HCT). CMV-seropositive HCT recipients who received letermovir prophylaxis from 2018 to 2020 at our center were evaluated for letermovir resistance and breakthrough CMV reactivation. Two-hundred twenty-six letermovir recipients were identified and 7/15 (47%) with CMV DNAemia ≥200 IU/mL were successfully genotyped for UL56 resistance. A single C325Y resistance mutation was identified in an umbilical cord blood recipient. Ninety-five (42%), 43 (19%), and 15 (7%) patients had breakthrough CMV at any level, ≥150 IU/mL, and ≥500 IU/mL, respectively. Risk factors for breakthrough CMV reactivation at each viral threshold were examined. Cumulative steroid exposure was the strongest risk factor for CMV at all evaluated viral thresholds. Graft-versus-host disease prophylaxis with post-transplantation cyclophosphamide (aHR 2.34, 95% CI 1.28–4.28, p = 0.001) or calcineurin inhibitors plus mycophenolate (aHR 2.24, 95% CI 1.30–3.86, p = 0.004) were also associated with an increased risk of CMV reactivation at any level. De novo letermovir resistance is rare and can be successfully treated using other antivirals. Letermovir effectively prevents clinically significant CMV, however, subclinical CMV reactivation occurs frequently at our center.

We and others have shown that tissue-resident memory CD4 + T cells play a critical role in maintaining chronic GVHD pathogenesis. However, the cellular and molecular mechanisms remain largely unknown. Ly108 and (TCF1) expression have been shown to reflect the stemness of memory CD8 + T cells. In the current studies, using the markers Ly108 (TCF1) and CD69, we identified four subsets of memory CD4 + T (Tm) cells in the GVHD target tissues, including Ly108 + CD69 - and Ly108 +CD69 + stem-like Tm cells, as well as Ly108 - CD69 - and Ly108 - CD69 + differentiatedTm cells. Compared to other Tm subsets, the Ly108 - CD69 + subset expressed the highest levels of IFN-γ and GM-CSF without upregulating anergy/exhaustion markers, indicating that they represent a terminally differentiated, tissue resident, pathogenic CD4 + memory T (Trm) subset. The Ly108 + Tm subsets showed self-renewal capacity and differentiation into Ly108 - Tm subsets, as demonstrated by adoptive transfer experiments. Using single-cell RNA sequencing (scRNA-seq) in conjunction with scTCR-seq analysis, we observed that Ly108 +CD69 - Tm subset was clonally related to the expanded Ly108 - CD69 - and Ly108 - CD69 + Tm subsets, suggesting a clonal expansion and differentiation of Ly108 + CD69 - stem-like memory T (Tsm) cells. In addition, we found that IFN-γ primed donor-type antigen-presenting cells (APCs) play an essential role in optimizing the transition from CD4 + Tsm cells to CD4 + Trm cells in STAT3- and BCL6-dependent manner, as indicated by ATAC-Seq analysis. Our results have elucidated a novel pathway of clonal expansion and differentiation of Tsm cells to Trm cells in the GVHD target tissues. These observations provide cellular and molecular mechanisms that explain how chronic GVHD is perpetuated by memory T cells in local tissues. XK and BW contributed equally.

Successful treatment of chronic graft-versus-host disease (GvHD) often requires long-term systemic therapy (ST). Durable discontinuation of ST reflects the resolution of active chronic GvHD. We evaluated the factors associated with durable ST discontinuation, defined as cessation of all ST for ≥12 months, using data from two prospectively followed cohorts from the Chronic GvHD Consortium (n=684). Transplant sources were peripheral blood (89%), bone marrow (6.6%), and cord blood (4.4%) from HLA matched related (37.6%), HLA matched unrelated (45%), and other donor types (18%). Half of the patients received non-myeloablative conditioning. The median time from transplantation to chronic GvHD diagnosis was 7.7 months (range, 1.0–141.3) and the median time from chronic GvHD onset to enrollment into the cohorts was 0.9 months (range, 0.0-12.0). The cumulative incidence estimate of durable ST discontinuation was 32% (95% confidence interval: 28%-37%) at 10 years after enrollment into the cohort. Among patients who discontinued ST, the median time from chronic GvHD diagnosis to durable ST discontinuation was 3.6 years (range, 1.2-10.5). In multivariate analysis, patients who received myeloablative conditioning, had chronic GvHD manifested as moderate/severe lower gastrointestinal involvement, and had a higher (worse) Lee symptom overall score were less likely to attain durable ST discontinuation. In contrast, mild lower gastrointestinal involvement and cord blood (vs. peripheral blood) as the graft source were associated with a greater likelihood of ST discontinuation. Although a minority of patients can discontinue ST permanently, most patients require prolonged ST. Viewing chronic GvHD in this way has implications for management approaches.

Preventing graft-versus-host disease (GVHD) while preserving graft-versus-leukemia/lymphoma (GVL) activity remains an elusive goal for allogeneic hematopoietic cell transplantation (HCT). It was reported by others that while donor naïve CD8 + T cells mediate both GVHD and GVL activity, donor memory CD8 + T cells could mediate GVL activity without GVHD. We recently reported that in vivo specific blockade of PD-L1/CD80 interactions augment tumor immunity mediated by memory CD8 + T cells (Zhang et al: PNAS 2023). In the current studies, we evaluated the impact of blockade of PD-L1/CD80 on GVHD induced by donor naïve CD8 + T cells and GVL activity-mediated by donor memory CD8 + T cells. Sorted naïve CD8 + T or memory CD8 + T cells and TCD-BM cells from C57BL/6 donors were transplanted into lethal TBI-conditioned BALB/c recipients with or without bearing ALL cancer cells. 4 days after HCT, the recipients were injected I.P. with anti-PD-L1 mAb (43H12) that specifically blocks PD-L1/CD80 interactions without inferring PD-L1/PD-1 interactions or control IgG. We observed that naïve but not memory CD8 + T cells severely infiltrated GVHD target tissues, and the memory CD8 + T cells expanded mainly in the lymphoid tissues. In vivo blockade of PD-L1/CD80 interactions augmented GVHD induced by the naïve T cells and GVL activity mediated by the memory CD8 + T cells. In addition, blockade of PD-L1/CD80 interactions increased production of granzyme B and inflammatory cytokines (IFN-g and TNF-α) of activated donor CD8 + T cells. Since cytolytic activity of effector CD8 + T cell is reported to be associated with its metabolic fitness, we evaluated the effect of blockade PD-L1/CD80 interactions on metabolism of alloreactive donor CD8 + T cells. And blockade of the interactions enhanced the fitness of mitochondria, as indicated by electronic microscopy analysis. The blockade also increased ECAR, OCR, and ATP production of the activated CD8 + T cells, with increased influx of glucose and fatty acids; and the blockade augmented mitophagy of the activated CD8 + T cells, as indicated by reducing mitochondria mass and dysfunctional mitochondria in the CD8 + T cells. The results indicate that 1) PD-L1/CD80 interactions play an important role in regulating the mitochondria function of activated alloreactive CD8 + T cells; 2) Blockade of PD-L1/CD80 interactions can augment GVL activity mediated by donor memory T cells without augmenting GVHD. This is different from blockade of PD-L1/PD-1 interactions that resulted in lethal GVHD. *Zhang and Song are co-first authors of this abstract

Failure-free survival (FFS), defined as the absence of new systemic treatment, recurrence of original malignancy and mortality not associated with recurrence after allogeneic hematopoietic stem cell transplantation (HCT), is a robust clinical measure to interpret results of initial systemic treatment of chronic graft-versus-host disease (cGVHD). We evaluate FFS after initial treatment of cGVHD in a mixed-race cohort from a resource-constrained country. This retrospective study included 354 consecutive patients after their first HCT between January 2014 and August 2020, who received initial systemic treatment for moderate or severe cGVHD at 13 Brazilian centers. Cox regression models were used to identify risk factors for treatment failure. The overall median follow-up among survivors was 28 months (range 1-71) after initial treatment. FFS was 89% at 6 months, 71% at 1 year and 52% at 2 years. New systemic treatment was the major cause of failure. In multivariable models, prior grades II-IV acute GVHD, a National Institutes of Health severity score of 3 in liver, gastrointestinal tract or lung involvement, and onset of initial treatment of cGVHD within 12 months after transplantation were all associated with an increased risk of treatment failure. Our results could serve as a benchmark for the design of future clinical trials evaluating initial treatment of cGVHD in resource-constrained locations.

Some retrospective studies have suggested that long-term donor statin use may protect against graft-versus-host disease (GVHD) in patients receiving cyclosporine (CSP)-based immunosuppression after allogeneic hematopoietic cell transplantation (HCT), but prospective studies of short-term treatment of donors with statin have shown conflicting results. We conducted 2 consecutive prospective clinical trials to assess whether donor statin treatment was associated with protection against severe acute GVHD (aGVHD). In a single-arm phase II trial (study 1), we evaluated whether short-term statin treatment of HLA-matched related donors for 14 days before HCT prevented grade III-IV aGVHD. In a prospective observational cohort study (study 2), we evaluated whether longer-term (>14 days) donor statin use was required for GVHD-protective effects. Study 1 was terminated after 6 of the 35 recipients (17%) developed grade III-IV GVHD. For study 2, we identified 135 patients whose unrelated donors had received long-term treatment with statins up to the time of HCT and 4942 patients whose donors had not received long-term statin treatment. The adjusted odds ratio for grade III-IV aGVHD (statin versus no statin) was .83 (95% confidence interval [CI], .46 to 1.50; P = .54). Multivariable analysis showed no statistically significant differences between the 2 groups in the risk of grade II-IV aGVHD, chronic GVHD, nonrelapse mortality, recurrent malignancy, or overall mortality. Among patients receiving CSP-based immunosuppression, including 35 with donors receiving long-term statin treatment and 973 with donors who did not receive statins, the adjusted odds ratio of grade III-IV aGVHD was .30 (95% CI, .07 to 1.35; P = .12). In study 1, short-term statin treatment of donors was ineffective in preventing grade III-IV GVHD. In study 2, in the prespecified subgroup of recipients given CSP-based immunosuppression, nondefinitive evidence suggested that donor statin use was associated with a reduced risk of severe aGVHD.(c) 2023 The American Society for Transplantation and Cellular Therapy. Published by Elsevier Inc. All rights reserved.

STAT3 deficiency (STAT3–/–) in donor T cells prevents graft-versus-host disease (GVHD), but the impact on graft-versus-leukemia (GVL) activity and mechanisms of GVHD prevention remains unclear. Here, using murine models of GVHD, we show that STAT3–/– donor T cells induced only mild reversible acute GVHD while preserving GVL effects against nonsusceptible acute lymphoblastic leukemia (ALL) cells in a donor T cell dose–dependent manner. GVHD prevention depended on programmed death ligand 1/programmed cell death protein 1 (PD-L1/PD-1) signaling. In GVHD target tissues, STAT3 deficiency amplified PD-L1/PD-1 inhibition of glutathione (GSH)/Myc pathways that regulate metabolic reprogramming in activated T cells, with decreased glycolytic and mitochondrial ATP production and increased mitochondrial ROS production and dysfunction, leading to tissue-specific deletion of host-reactive T cells and prevention of GVHD. Mitochondrial STAT3 deficiency alone did not reduce GSH expression or prevent GVHD. In lymphoid tissues, the lack of host-tissue PD-L1 interaction with PD-1 reduced the inhibition of the GSH/Myc pathway despite reduced GSH production caused by STAT3 deficiency and allowed donor T cell functions that mediate GVL activity. Therefore, STAT3 deficiency in donor T cells augments PD-1 signaling–mediated inhibition of GSH/Myc pathways and augments dysfunction of T cells in GVHD target tissues while sparing T cells in lymphoid tissues, leading to prevention of GVHD while preserving GVL effects.

The significance of rare germline mutations in transplant-associated thrombotic microangiopathy (TA-TMA) is not well studied. We performed a genetic association study in 100 adult TA-TMA patients vs. 98 post-transplant controls after matching by race, sex, and year. We focused on 5 pathways in complement, von Willebrand factor (VWF) function and related proteins, VWF clearance, ADAMTS13 function and related proteins, and endothelial activation (3641variants in 52 genes). In the primary analysis focused on 189 functional rare variants, no differential variant enrichment was observed in any of the pathways; specifically, 29 % TA-TMA and 33 % controls had at least 1 rare complement mutation. In the secondary analysis focused on 37 rare variants predicted to be pathogenic or likely pathogenic by ClinVar, Complement Database, or REVEL in-silico prediction tool, rare variants in the VWF clearance pathway were found to be significantly associated with TA-TMA (p = 0.008). On the gene level, LRP1 was the only one with significantly increased variants in TA-TMA in both analyses (p = 0.025 and 0.015). In conclusion, we did not find a significant association between rare variants in the complement pathway and TA-TMA; however, we discovered a new signal in the VWF clearance pathway driven by the gene LRP1 among likely pathogenic variants.

Importance:Prior studies have demonstrated an association between cutaneous chronic graft-vs-host disease (cGVHD) and mortality. Assessment of the prognostic value of different measures of disease severity would assist in risk stratification.Objective:To compare the prognostic value of body surface area (BSA) and National Institutes of Health (NIH) Skin Score on survival outcomes stratified by erythema and sclerosis subtypes of cGVHD.Design, Setting, and Participants:Multicenter prospective cohort study from the Chronic Graft-vs-Host Disease Consortium including 9 medical centers in the US, enrolled from 2007 through 2012 and followed until 2018. Participants were adults and children with a diagnosis of cGVHD requiring systemic immunosuppression and with skin involvement during the study period, who had longitudinal follow-up. Data analysis was performed from April 2019 to April 2022.Exposures:Patients underwent continuous BSA estimation and categorical NIH Skin Score grading of cutaneous cGVHD at enrollment and every 3 to 6 months thereafter.Main Outcomes and Measures:Nonrelapse mortality (NRM) and overall survival (OS), compared between BSA and NIH Skin Score longitudinal prognostic models, adjusted for age, race, conditioning intensity, patient sex, and donor sex.Results:Of 469 patients with cGVHD, 267 (57%) (105 female [39%]; mean [SD] age, 51 [12] years) had cutaneous cGVHD at enrollment, and 89 (19%) developed skin involvement subsequently. Erythema-type disease had earlier onset and was more responsive to treatment compared with sclerosis-type disease. Most cases (77 of 112 [69%]) of sclerotic disease occurred without prior erythema. Erythema-type cGVHD at first follow-up visit was associated with NRM (hazard ratio, 1.33 per 10% BSA increase; 95% CI, 1.19-1.48; P < .001) and OS (hazard ratio, 1.28 per 10% BSA increase; 95% CI, 1.14-1.44; P < .001), while sclerosis-type cGVHD had no significant association with mortality. The model with erythema BSA collected at baseline and first follow-up visits retained 75% of the total prognostic information (from all covariates including BSA and NIH Skin Score) for NRM and 73% for OS, with no statistical difference between prognostic models (likelihood ratio test χ2, 5.9; P = .05). Conversely, NIH Skin Score collected at the same intervals lost significant prognostic information (likelihood ratio test χ2, 14.7; P < .001). The model incorporating NIH Skin Score instead of erythema BSA accounted for only 38% of the total information for NRM and 58% for OS.Conclusions and Relevance:In this prospective cohort study, erythema-type cutaneous cGVHD was associated with increased risk of mortality. Erythema BSA collected at baseline and follow-up predicted survival more accurately than the NIH Skin Score in patients requiring immunosuppression. Accurate assessment of erythema BSA may assist in identifying patients with cutaneous cGVHD at high risk for mortality.