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Abstract: Graft-versus-host disease (GVHD) is a major life-threatening complication that occurs after allogeneic hematopoietic cell transplantation (HCT). Although adult tissue stem cells have been identified as targets of GVHD in the skin and gut, their role in hepatic GVHD is yet to be clarified. In the current study, we explored the fate of bile duct stem cells (BDSCs), capable of generating liver organoids in vitro, during hepatic GVHD after allogeneic HCT. We observed a significant expansion of biliary epithelial cells (BECs) on injury early after allogeneic HCT. Organoid-forming efficiency from the bile duct was also significantly increased early after allogeneic HCT. Subsequently, the organoid-forming efficiency from bile ducts was markedly decreased in association with the reduction of BECs and the elevation of plasma concentrations of bilirubin, suggesting that GVHD targets BDSCs and impairs the resilience of BECs. The growth of liver organoids in the presence of liver-infiltrating mononuclear cells from allogeneic recipients, but not from syngeneic recipients, was significantly reduced in a transforming growth factor-β (TGF-β)-dependent manner. Administration of SB-431542, an inhibitor of TGF-β signaling, from day 14 to day 28, protected organoid-forming BDSCs against GVHD and mitigated biliary dysfunction after allogeneic HCT, suggesting that BDSCs are a promising therapeutic target for hepatic GVHD., (© 2024 American Society of Hematology. Published by Elsevier Inc. All rights are reserved, including those for text and data mining, AI training, and similar technologies.)

Competing Interests: Declaration of competing interest None.

Purpose: Lupus-like chronic graft-versus-host disease (cGVHD) has been previously described, but the ocular findings have not been elucidated. Recipient mice in a lupus-like cGVHD model manifested notable and persistent ocular surface phenotypes. Herein, we further explored immunopathogenic mechanisms underlying these ocular phenotypes., Methods: A previously described lupus-like cGVHD model was established by intraperitoneal injection of splenocytes from bm12 mice into C57BL/6J mice. Systemic findings were evaluated for the presence of splenomegaly, proteinuria, and autoantibodies. Comprehensive evaluations were conducted on ocular manifestations and immunopathological features in this model., Results: The lupus-like cGVHD model was successfully constructed 2 weeks post-transplantation. The recipient mice developed lupus-like phenotypes, including splenomegaly, proteinuria, and increased autoantibodies, and their ocular presentations included corneal epithelial defects and decreased tear secretion. Histological analysis revealed a reduction in corneal nerve fiber density and corneal endothelial cells, along with conjunctival fibrosis and loss of goblet cells. Moreover, cGVHD induced progressive aggravation of immune cell infiltration and fibrosis in the lacrimal glands. RNA-Sequencing (RNA-seq) results of the lacrimal glands demonstrated that the differentially expressed genes (DEGs) between the control and cGVHD groups were associated with GVHD pathways. Immune infiltration analysis using RNA-seq and flow cytometry confirmed that CD8+ T lymphocytes predominantly constituted the inflammatory infiltrating cells within the lacrimal glands., Conclusions: This lupus-like cGVHD model (bm12→C57BL/6J) exhibited persistent ocular surface manifestations, characterized by immune infiltration of CD8+ T lymphocytes in the lacrimal glands. Thus, this ocular cGVHD model may be used to explore the underlying mechanisms and discover novel therapeutic interventions.

Calcineurin inhibitors (CNIs) constitute the backbone of modern acute graft-versus-host disease (aGVHD) prophylaxis regimens but have limited efficacy in the prevention and treatment of chronic GVHD (cGVHD). We investigated the effect of CNIs on immune tolerance after stem cell transplantation with discovery-based single-cell gene expression and T cell receptor (TCR) assays of clonal immunity in tandem with traditional protein-based approaches and preclinical modeling. While cyclosporin and tacrolimus suppressed the clonal expansion of CD8+ T cells during GVHD, alloreactive CD4+ T cell clusters were preferentially expanded. Moreover, CNIs mediated reversible dose-dependent suppression of T cell activation and all stages of donor T cell exhaustion. Critically, CNIs promoted the expansion of both polyclonal and TCR-specific alloreactive central memory CD4+ T cells (TCM) with high self-renewal capacity that mediated cGVHD following drug withdrawal. In contrast to posttransplant cyclophosphamide (PT-Cy), CSA was ineffective in eliminating IL-17A-secreting alloreactive T cell clones that play an important role in the pathogenesis of cGVHD. Collectively, we have shown that, although CNIs attenuate aGVHD, they paradoxically rescue alloantigen-specific TCM, especially within the CD4+ compartment in lymphoid and GVHD target tissues, thus predisposing patients to cGVHD. These data provide further evidence to caution against CNI-based immune suppression without concurrent approaches that eliminate alloreactive T cell clones.

Abstract: Fanconi anemia (FA) is an inherited DNA repair disorder characterized by bone marrow (BM) failure, developmental abnormalities, myelodysplasia, leukemia, and solid tumor predisposition. Allogeneic hematopoietic stem cell transplantation (allo-HSCT), a mainstay treatment, is limited by conditioning regimen-related toxicity and graft-versus-host disease (GVHD). Antibody-drug conjugates (ADCs) targeting hematopoietic stem cells (HSCs) can open marrow niches permitting donor stem cell alloengraftment. Here, we report that single dose anti-mouse CD45-targeted ADC (CD45-ADC) facilitated stable, multilineage chimerism in 3 distinct FA mouse models representing 90% of FA complementation groups. CD45-ADC profoundly depleted host stem cell enriched Lineage-Sca1+cKit+ cells within 48 hours. Fanca-/- recipients of minor-mismatched BM and single dose CD45-ADC had peripheral blood (PB) mean donor chimerism >90%; donor HSCs alloengraftment was verified in secondary recipients. In Fancc-/- and Fancg-/- recipients of fully allogeneic grafts, PB mean donor chimerism was 60% to 80% and 70% to 80%, respectively. The mean percent donor chimerism in BM and spleen mirrored PB results. CD45-ADC-conditioned mice did not have clinical toxicity. A transient <2.5-fold increase in hepatocellular enzymes and mild-to-moderate histopathological changes were seen. Under GVHD allo-HSCT conditions, wild-type and Fanca-/- recipients of CD45-ADC had markedly reduced GVHD lethality compared with lethal irradiation. Moreover, single dose anti-human CD45-ADC given to rhesus macaque nonhuman primates on days -6 or -10 was at least as myeloablative as lethal irradiation. These data suggest that CD45-ADC can potently promote donor alloengraftment and hematopoiesis without significant toxicity or severe GVHD, as seen with lethal irradiation, providing strong support for clinical trial considerations in highly vulnerable patients with FA., (© 2024 American Society of Hematology. Published by Elsevier Inc. All rights are reserved, including those for text and data mining, AI training, and similar technologies.)

Background: Systemic sclerosis (SSc) is an autoimmune disease characterized by vascular injury and inflammation, followed by excessive fibrosis of the skin and other internal organs, including the lungs. CX3CL1 (fractalkine), a chemokine expressed on endothelial cells, supports the migration of macrophages and T cells that express its specific receptor CX3CR1 into targeted tissues. We previously reported that anti-CX3CL1 monoclonal antibody (mAb) treatment significantly inhibited transforming growth factor (TGF)-β1-induced expression of type I collagen and fibronectin 1 in human dermal fibroblasts. Additionally, anti-mouse CX3CL1 mAb efficiently suppressed skin inflammation and fibrosis in bleomycin- and growth factor-induced SSc mouse models. However, further studies using different mouse models of the complex immunopathology of SSc are required before the initiation of a clinical trial of CX3CL1 inhibitors for human SSc., Methods: To assess the preclinical utility and functional mechanism of anti-CX3CL1 mAb therapy in skin and lung fibrosis, a sclerodermatous chronic graft-versus-host disease (Scl-cGVHD) mouse model was analyzed with immunohistochemical staining for characteristic infiltrating cells and RNA sequencing assays., Results: On day 42 after bone marrow transplantation, Scl-cGVHD mice showed increased serum CX3CL1 level. Intraperitoneal administration of anti-CX3CL1 mAb inhibited the development of fibrosis in the skin and lungs of Scl-cGVHD model, and did not result in any apparent adverse events. The therapeutic effects were correlated with the number of tissue-infiltrating inflammatory cells and α-smooth muscle actin (α-SMA)-positive myofibroblasts. RNA sequencing analysis of the fibrotic skin demonstrated that cGVHD-dependent induction of gene sets associated with macrophage-related inflammation and fibrosis was significantly downregulated by mAb treatment. In the process of fibrosis, mAb treatment reduced cGVHD-induced infiltration of macrophages and T cells in the skin and lungs, especially those expressing CX3CR1., Conclusions: Together with our previous findings in other SSc mouse models, the current results indicated that anti-CX3CL1 mAb therapy could be a rational therapeutic approach for fibrotic disorders, such as human SSc and Scl-cGVHD., (© 2024. The Author(s).)

Lethal graft-versus-host disease (GVHD) is the major complication of allogeneic hematopoietic stem-cell transplantation (Allo-HSCT). Pyruvate kinase M2 (PKM2) is essential for CD4+ T-cell differentiation. Using the well-characterized mouse models of Allo-HSCT, we explored the effects of TEPP-46-induced PKM2 tetramerization on GVHD and graft-versus-leukemia (GVL) activity. TEPP-46 administration significantly improved the survival rate of GVHD. The severity of GVHD and histopathological damage of GVHD-targeted organs were obviously alleviated by PKM2 tetramerization. Additionally, tetramerized PKM2 inhibited the activation of NF-κB pathway and decreased the inflammation level of GVHD mice. PKM2 tetramerization blocked Th1 and Th17 cell differentiation and secretion of pro-inflammatory cytokine (IFN-γ, TNF-α, and IL-17). Meanwhile, differentiation of Treg cells and IL-10 secretion were promoted by tetramerized PKM2. These findings demonstrated that PKM2 enhanced the augment of Th1 and Th17 cells to accelerate the progression of GVHD, and allosteric activation of PKM2 targeted Th1 and Th17 cells attenuated GVHD. Furthermore, we also confirmed that TEPP-46 administration did not compromise GVL activity and resulted in slightly improvement of leukemia-free survive. Thus, targeting Th1 and Th17 cell response with PKM2 allosteric activator may be a promising therapeutic strategy for GVHD prevention while preserving the GVL activity in patients receiving Allo-HSCT., (© 2024. The Author(s) under exclusive licence to Japan Human Cell Society.)

Adenovirus can cause severe disease in hematopoietic stem cell transplant (HSCT) patients. Histopathologic features of this infection in gastrointestinal biopsies and their distinction from graft-versus-host disease (GVHD) have been incompletely studied. We retrospectively identified patients with gastrointestinal adenovirus infection. H&E-stained sections were reviewed and the histologic features were recorded. The extent of immunostaining was determined using a semiquantitative scale and a maximum number of positive cells per high-power field. Information regarding the clinical course and endoscopic findings were obtained from the electronic medical records. The study group included 32 HSCT patients. Most (81%) presented with diarrhea and detectable virus in the serum. Twenty patients had multiorgan involvement in the gastrointestinal tract, mostly in the duodenum (62%) and colon (56%). Characteristic features included apoptotic epithelial cells with nuclear disarray (84%) and tufted aggregates of degenerating epithelial cells (69%), the latter of which was more commonly seen in the study population more than a control group of HSCT patients with GI involvement by GVHD. Viral inclusions were limited to the superficial epithelium in 59% of samples, and the density of viral inclusions within biopsies was variable (grade 1: 40%, grade 2: 38%, and grade 3: 22%). Following therapy, 10 patients (30%) improved and 14 (42%) had progressive disease. Patients with disease progression were often older (64 vs. 36 years, P =0.01) with higher serologic viral loads, prior history of GVHD, multifocal involvement, and increased number and density of immunoreactive nuclei. Adenovirus infection elicits a spectrum of histologic changes that can simulate or occur in combination with gastrointestinal GVHD. Patients with progressive disease are more likely to have high viral loads and more extensive infection of the gastrointestinal tract., Competing Interests: Conflicts of Interest and Source of Funding: The authors have disclosed that they have no significant relationships with, or financial interest in, any commercial companies pertaining to this article., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Neuroinflammation is a recognized complication of immunotherapeutic approaches such as immune checkpoint inhibitor treatment, chimeric antigen receptor therapy, and graft versus host disease (GVHD) occurring after allogeneic hematopoietic stem cell transplantation. While T cells and inflammatory cytokines play a role in this process, the precise interplay between the adaptive and innate arms of the immune system that propagates inflammation in the central nervous system remains incompletely understood. Using a murine model of GVHD, we demonstrate that type 2 cannabinoid receptor (CB2R) signaling plays a critical role in the pathophysiology of neuroinflammation. In these studies, we identify that CB2R expression on microglial cells induces an activated inflammatory phenotype that potentiates the accumulation of donor-derived proinflammatory T cells, regulates chemokine gene regulatory networks, and promotes neuronal cell death. Pharmacological targeting of this receptor with a brain penetrant CB2R inverse agonist/antagonist selectively reduces neuroinflammation without deleteriously affecting systemic GVHD severity. Thus, these findings delineate a therapeutically targetable neuroinflammatory pathway and have implications for the attenuation of neurotoxicity after GVHD and potentially other T cell-based immunotherapeutic approaches.

Background: Pediatric hematopoietic stem cell transplantation (HCT) is an intensive medical procedure that places substantial financial and logistical burdens on families and is associated with significant health risks, such as graft-versus-host disease (GVHD), and infections. The influence of the social determinants of health (SDoH) on outcomes following pediatric HCT is understudied. This study aimed to examine whether SDoH predicts outcomes following pediatric HCT., Procedure: Data were collected from 84 children who received HCT (M age  = 5.8 years, SD = 3.7) and their primary caregiver. Detailed demographic information was collected from caregivers at baseline, and child health information was extracted from the electronic medical records. Multivariate logistic regression was used to examine the association between SDoH and health outcomes within a 24-month period following pediatric HCT., Results: After controlling for malignancy as reason for transplant and donor type, lower family income predicted the incidence of chronic GVHD. Neighborhood deprivation, total family income, public health insurance, caregiver relationship status, caregiver educational attainment, and perceived family financial difficulties did not predict acute GVHD or the number of infections., Conclusions: Total family income is a simple family indicator of SDoH that predicts chronic GVHD after pediatric allogeneic HCT. These findings provide further support for the importance of screening of child and family SDoH risks to ensure that fundamental needs can be met to mitigate potential health disparities for up to 2 years following pediatric HCT., (© 2024 Wiley Periodicals LLC.)

Purpose: Aging is a well-established risk factor for meibomian gland dysfunction (MGD). We previously reported an accelerated cellular senescence phenomenon in the lacrimal glands of a murine model of chronic graft-versus-host disease (cGVHD). Herein, we aimed to elucidate the relationship between cellular senescence and MGD in cGVHD mice, utilizing the senolytic agent ABT-263., Methods: A cGVHD mouse model was established through allogeneic bone marrow transplantation (BMT) from B10.D2 to BALB/c mice. Subsequently, cGVHD mice were treated with either ABT-263 or vehicle. The eyelids of recipients were analyzed at 4-week intervals post-BMT in both groups., Results: Meibomian gland (MG) area was significantly smaller in cGVHD mice than in syngeneic control mice. ABT-263-treated mice retained a significantly larger MG area than their vehicle-treated counterparts. Pathological and immunohistochemical examinations revealed significant reductions in eyelid tissue inflammation and pathological fibrosis in the ABT-263 group compared to that in the vehicle-treated group. Additionally, expression of DNA damage markers, senescent cell markers, and senescence-associated secretory phenotype (SASP) factors was elevated in the eyelids of cGVHD mice compared with that in syngeneic mice. The expression of these cellular senescence-associated molecules was considerably suppressed in ABT-263-treated eyelids compared to that in vehicle-treated ones., Conclusions: Cellular senescence, along with expression of SASP factors, exhibited increased activity in the eyelids, particularly in the MGs of cGVHD mice. ABT-263 mitigated the severity of MGD. These findings highlight the potential of targeting cellular senescence as an effective approach for MGD treatment in cGVHD., Competing Interests: Declaration of competing interest We received grants from Tsubota Laboratory during the study period. The sponsors had no control over the experiments, interpretation, writing, or publication of the manuscript. S. Sato., Y.O., E.S., and K.T. have domestically applied for patents (application number: JP 2019–004730; published as JPA2020-111,548, application number: JP2023-033134). K.T. reports serving as the chief executive officer for the Tsubota Laboratory, a company working on treatment, prevention, and medical devices for dry eye. The other authors declare no conflicts of interest., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Abstract: Allogeneic hematopoietic cell transplantation (HCT) is a curative therapy for hematological malignancies for which graft-versus-host disease (GVHD) remains a major complication. The use of donor T-regulatory cells (Tregs) to prevent GVHD appears promising, including in our previous evaluation of an engineered graft product (T-reg graft) consisting of the timed, sequential infusion of CD34+ hematopoietic stem cells and high-purity Tregs followed by conventional T cells. However, whether immunosuppressive prophylaxis can be removed from this protocol remains unclear. We report the results of the first stage of an open-label single-center phase 2 study (NCT01660607) investigating T-reg graft in myeloablative HCT of HLA-matched and 9/10-matched recipients. Twenty-four patients were randomized to receive T-reg graft alone (n = 12) or T-reg graft plus single-agent GVHD prophylaxis (n = 12) to determine whether T-reg graft alone was noninferior in preventing acute GVHD. All patients developed full-donor myeloid chimerism. Patients with T-reg graft alone vs with prophylaxis had incidences of grade 3 to 4 acute GVHD of 58% vs 8% (P = .005) and grade 3 to 4 of 17% vs 0% (P = .149), respectively. The incidence of moderate-to-severe chronic GVHD was 28% in the T-reg graft alone arm vs 0% with prophylaxis (P = .056). Among patients with T-reg graft and prophylaxis, CD4+ T-cell-to-Treg ratios were reduced after transplantation, gene expression profiles showed reduced CD4+ proliferation, and the achievement of full-donor T-cell chimerism was delayed. This study indicates that T-reg graft with single-agent tacrolimus is preferred over T-reg graft alone for the prevention of acute GVHD. This trial was registered at www.clinicaltrials.gov as #NCT01660607., (© 2024 by The American Society of Hematology. Licensed under Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0), permitting only noncommercial, nonderivative use with attribution. All other rights reserved.)

Anti-inflammatory and immune suppressive agents are required to moderate hyper-activation of lymphocytes under disease conditions or organ transplantation. However, selective disruption of mitochondrial redox has not been evaluated as a therapeutic strategy for suppression of T-cell-mediated pathologies. Using mitochondrial targeted curcumin (MitoC), we studied the effect of mitochondrial redox modulation on T-cell responses by flow cytometry, transmission electron microscopy, transcriptomics, and proteomics, and the role of Nrf2 was studied using Nrf2 - / - mice. MitoC decreased mitochondrial TrxR activity, enhanced mitochondrial ROS (mROS) production, depleted mitochondrial glutathione, and suppressed activation-induced increase in mitochondrial biomass. This led to suppression of T-cell responses and metabolic reprogramming towards T reg differentiation. MitoC induced nuclear translocation and DNA binding of Nrf2, leading to upregulation of Nrf2-dependent genes and proteins. MitoC-mediated changes in mitochondrial redox and modulation of T-cell responses are abolished in Nrf2 - / - mice. Restoration of mitochondrial thiols abrogated inhibition of T-cell responses. MitoC suppressed alloantigen-induced lymphoblast formation, inflammatory cytokines, morbidity, and mortality in acute graft-versus-host disease mice. Disruption of mitochondrial thiols but not mROS increase inculcates an Nrf2-dependent immune-suppressive disposition in T cells for the propitious treatment of graft-versus-host disease., (© 2024 John Wiley & Sons Ltd.)

Tissue-intrinsic mechanisms that regulate severity of systemic pathogenic immune-mediated diseases, such as acute graft-versus-host disease (GVHD), remain poorly understood. Following allogeneic hematopoietic stem cell transplantation, autophagy, a cellular stress protective response, is induced in host nonhematopoietic cells. To systematically address the role of autophagy in various host nonhematopoietic tissues, both specific classical target organs of acute GVHD (intestines, liver, and skin) and organs conventionally not known to be targets of GVHD (kidneys and heart), we generated mice with organ-specific knockout of autophagy related 5 (ATG5) to specifically and exclusively inhibit autophagy in the specific organs. When compared with wild-type recipients, animals that lacked ATG5 in the gastrointestinal tract or liver showed significantly greater tissue injury and mortality, while autophagy deficiency in the skin, kidneys, or heart did not affect mortality. Treatment with the systemic autophagy inducer sirolimus only partially mitigated GVHD mortality in intestine-specific autophagy-deficient hosts. Deficiency of autophagy increased MHC class I on the target intestinal epithelial cells, resulting in greater susceptibility to damage by alloreactive T cells. Thus, autophagy is a critical cell-intrinsic protective response that promotes tissue tolerance and regulates GVHD severity.

Background: Graft-versus-host disease (GvHD) is a major life-threatening complication of allogeneic haematopoietic stem cell transplantation (HSCT), limiting the broad application of HSCT for haematological malignancies. Cutaneous GvHD is described as a post-transplant inflammatory reaction by skin-infiltrating donor T cells and remaining recipient tissue-resident memory T cells. Despite the major influence of lymphocytes on GvHD pathogenesis, the complex role of mononuclear phagocytes (MNPs) in tissues affected by GvHD is increasingly appreciated., Objectives: To characterize the identity, origin and functions of MNPs in patients with acute cutaneous GvHD., Methods: Using single-cell RNA sequencing and multiplex tissue immunofluorescence, we identified an increased abundance of MNPs in skin and blood from 36 patients with acute cutaneous GvHD. In cases of sex-mismatched transplantation, we used expression of X-linked genes to detect rapid tissue adaptation of newly recruited donor MNPs resulting in similar transcriptional states of host- and donor-derived macrophages within GvHD skin lesions., Results: We showed that cutaneous GvHD lesions harbour expanded CD163+ tissue-resident macrophage populations with anti-inflammatory and tissue-remodelling properties including interleukin-10 cytokine production. Cell-cell interaction analyses revealed putative signalling to strengthen regulatory T-cell responses. Notably, macrophage polarization in chronic cutaneous GvHD types was proinflammatory and drastically differed from acute GvHD, supporting the notion of distinct cellular players in different clinical GvHD subtypes., Conclusions: Overall, our data reveal a surprisingly dynamic role of MNPs after HSCT. Specific and time-resolved targeting to repolarize this cell subset may present a promising therapeutic strategy in combatting GvHD skin inflammation., Competing Interests: Conflicts of interest The authors declare no conflicts of interest related to this study., (© The Author(s) 2023. Published by Oxford University Press on behalf of British Association of Dermatologists.)

Obesity and diabetes can modulate immune responses, which may impact allogeneic HCT outcomes and GvHD. From the EBMT registry, we included 36,539 adult patients who underwent allogeneic HCT for a hematological malignancy between 2016 and 2020. Of these, 5228 (14%) had obesity (BMI ≥ 30 kg/m 2 ), 1415 (4%) had diabetes (requiring treatment with insulin or oral hypoglycemics), and 688 (2%) had obesity + diabetes pre-transplantation. Compared with patients without diabetes or obesity, the hazard ratio (HR) of grade II-IV acute GvHD was 1.00 (95% confidence interval [CI] 0.94-1.06, p = 0.89) for patients with obesity, 0.95 (CI 0.85-1.07, p = 0.43) for patients with diabetes, and 0.96 (CI 0.82-1.13, p = 0.63) for patients with obesity + diabetes. Non-relapse mortality was higher in patients with obesity (HR 1.08, CI 1.00-1.17, p = 0.047), diabetes (HR 1.40, CI 1.24-1.57, p < 0.001), and obesity + diabetes (HR 1.38, CI 1.16-1.64, p < 0.001). Overall survival after grade II-IV acute GvHD was lower in patients with diabetes (HR 1.46, CI 1.25-1.70, p < 0.001). Pre-transplantation diabetes and obesity did not influence the risk of developing acute GvHD, but pre-transplantation diabetes was associated with poorer survival after acute GvHD., (© 2023. The Author(s).)

Graft-versus-host disease (GVHD) is a serious complication of otherwise curative allogeneic haematopoietic stem cell transplants. Chronic GVHD induces pathological changes in peripheral organs as well as the brain and is a frequent cause of late morbidity and death after bone-marrow transplantation. In the periphery, bone-marrow-derived macrophages are key drivers of pathology, but recent evidence suggests that these cells also infiltrate into cGVHD-affected brains. Microglia are also persistently activated in the cGVHD-affected brain. To understand the involvement of these myeloid cell populations in the development and/or progression of cGVHD pathology, we here utilized the blood-brain-barrier permeable colony stimulating factor-1 receptor (CSF-1R) inhibitor PLX3397 (pexidartinib) at varying doses to pharmacologically deplete both cell types. We demonstrate that PLX3397 treatment during the development of cGVHD (i.e., 30 days post-transplant) improves disease symptoms, reducing both the clinical scores and histopathology of multiple cGVHD target organs, including the sequestration of T cells in cGVHD-affected skin tissue. Cognitive impairments associated with cGVHD and neuroinflammation were also attenuated by PLX3397 treatment. PLX3397 treatment prior to the onset of cGVHD (i.e., immediately post-transplant) did not change in clinical scores or histopathology. Overall, our data demonstrate significant benefits of using PLX3397 for the treatment of cGVHD and associated organ pathologies in both the periphery and brain, highlighting the therapeutic potential of pexidartinib for this condition., (© 2023. The Author(s).)

Background: Mesenchymal stem cells (MSCs) can alleviate graft-versus-host disease (GVHD) in hematopoietic stem cell transplantation (HSCT). MSCs-derived exosomes (MEXs) can mirror the biological function of their parent cells. Whether MEXs can alleviate GVHD like their parent cells or not is unclear. In this study, we investigate the effects of MEXs on GVHD and graft-versus-leukemia (GVL) effect in vitro and in HSCT animal models., Method: MSCs were produced using bone marrow mononuclear cells (MNCs), and MEXs were separated from the supernatants of MSCs. Electron microscopy, western blot, and nanoparticle tracking analysis (NTA) were used to determine the characteristics of MEXs. The immunomodulatory function of MEXs and their effects on GVHD and GVL were examined in vitro and in vivo ., Result: Like other cell-type derived exosomes, our data revealed that MEXs were also disc-shaped vesicles with a diameter of 100-200 nm under electron microscopy and were positive for the exosomal hallmark proteins. MEXs can notably inhibit the expression of costimulatory molecules and functional cytokine secretion of dendritic cells (DCs). Meanwhile, MEXs can exert suppressive effects on T lymphocyte proliferation and activation. Moreover, MEXs can also encourage the polarization of macrophages toward the M2 type. In animal HSCT models, MEXs can promote the differentiation of Treg cells in spleens, decrease the GVHD score, increase the survival rate of mice, and preserve the cytotoxic antileukemia effects of CD8 + T lymphocytes from recipient mice., Conclusion: These findings showed that MEXs exert their effects by inhibiting the immunomodulatory function of DCs, macrophages, and T lymphocytes. In the animal model, MEXs ameliorate the clinical symptoms of GVHD, while maintaining the antitumor effects of CD8 + T lymphocytes. Therefore, it can be inferred that MEXs can separate GVHD from GVL in HSCT. Our study suggests that MEXs have broad clinical application potential in the prevention and treatment of GVHD in HSCT in the near future., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Jiang, Zhao, Wang, Huang, Li, Liu, Wan and Hao.)

Objective: To investigate the preventive effect of low-dose porcine anti-thymocyte globulin (P-ATG) on graft versus host disease (GVHD) in patients' donors over 40 years old or female donors undergoing HLA-matched sibling donor hematopoietic stem cell transplantation (MSD-HSCT)., Methods: The clinical data of 30 patients received Low-dose Porcine antithymocyte globulin (P-ATG) as a part of the conditioning regimen (the P-ATG group), while the other 30 patients didn't receive ATG (the Non-ATG group)., Results: There was a significant difference in the incidence of aGVHD ([23.3 (10.1-39.7) %] vs [50.0 (30.8-66.5) %], P  = 0.028), grade II-IV aGVHD ([16.7 (5.94-32.1) %] vs [40.0 (22.4-57.0) %], P  = 0.049) and chronic GVHD (cGVHD) ([22.4 (6.03-45.1) %] vs [69.0 (43.4-84.8) %], P  = 0.001) between two groups. But there was no significant difference in terms of moderate-severe cGVHD ( P  = 0.129), 1-year relapse rate ( P  = 0.742), non-relapse mortality ( P  = 0.237), or overall survival ( P  = 0.441)., Conclusion: The application of low-dose P-ATG in patients/donors over 40 years old or female donors undergoing MSD-HSCT for hematological malignancy can significantly reduce the incidence of aGVHD, grade II-IV aGVHD and cGVHD, doesn't increase the risk of relapse.

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is widely applied for the treatment of hematologic malignancies, but autologous hematopoietic recovery (AR) after allo-HSCT is rare clinically, especially after myeloablative conditioning (MAC). The mechanism of AR remains unclear so far, but the prognosis for most patients is relatively good. Second transplantation is preferred after disease relapse. Starting from a real-life clinical case scenario, herein we reviewed some of the crucial issues of AR in light of recent refinements, and discussed our patients based on the current evidence., Competing Interests: Declaration of Competing Interest The authors declare that they have no competing interest., (Copyright © 2023. Published by Elsevier B.V.)

Chronic graft-versus-host disease (cGVHD) is a severe complication in long-term survivors of allogeneic hematopoietic stem cell transplantation. This disease is challenging to manage clinically due to a lack of validated tools to quantitatively measure skin sclerosis. The current gold standard for measuring skin sclerosis is the NIH Skin Score which has only moderate agreement among clinicians and experts. To more accurately assess skin sclerosis in cGVHD, the Myoton and durometer devices can be used to directly measure biomechanical parameters of the skin. However, the reproducibility of these devices is not known in patients with cGVHD. To determine this reproducibility, three observers independently measured 10 anatomic sites in each of seven patients with sclerotic cGVHD using the Myoton and durometer. Clinical reproducibility was measured by mean pairwise differences (U-statistic) and intraclass correlation coefficients (ICCs) with 95% confidence intervals (CIs). Mean pairwise differences, expressed in true physical units, were used to report typical errors for each anatomic site and device. Mean pairwise differences were less than 11% of the average overall values for all five Myoton parameters and durometer hardness. These were lower for Myoton creep (4.1%), relaxation time (4.7%), and frequency (5.1%) than decrement (9.0%), stiffness (10.4%), and durometer hardness (9.0%). Myoton parameters creep, relaxation time, and frequency showed promise for capturing skin biomechanics more accurately than Myoton stiffness, decrement, or durometer hardness. Mean pairwise differences trended highest in the shin and volar forearm and lowest in the dorsal forearm. The interobserver ICC for overall (averaged across all measured body sites of a patient) creep (0.94; 95% CI 0.87-1.00), relaxation time (0.96; 95% CI 0.90-1.00), and frequency (0.95; 95% CI 0.88-1.00), trended higher than that for decrement (0.43; 95% CI 0.00-0.88), stiffness (0.92; 95% CI 0.81-1.00), and durometer hardness (0.82; 95% CI 0.61-1.00). Similar trends were observed in healthy participants. These findings can help clinicians design better studies to assess therapeutic response to new cGVHD treatments and support the interpretation of future measurements., (© 2023. This is a U.S. Government work and not under copyright protection in the US; foreign copyright protection may apply.)

Post-transplant cyclophosphamide (PT-Cy) is effective for graft-versus-host disease (GVHD) prophylaxis, but it may cause dose-dependent toxicities, particularly in frail patients. Therefore, we compared the outcomes with a reduced PT-Cy total dose (70 mg/kg) to those with the standard PT-Cy dose (100 mg/kg) in haploidentical hematopoietic cell transplantation (HCT) patients aged ≥ 65 years and those with cardiac comorbidities. All consecutive patients with a hematological malignancy receiving peripheral blood stem cells (PBSCs) after a thiotepa-based conditioning with low-dose antithymocyte globulin were included. Thirty-three patients received PT-Cy at 70 mg/kg and 25 at 100 mg/kg. PT-Cy dose reduction did not increase the risk of GVHD and was associated with faster neutrophil and platelet recovery, and lower cumulative incidences of bacteremia (38% versus 72%, p = 0.004) and cardiac complications (12% versus 44%, p = 0.028). At 2 years, GVHD-free, relapse-free survival (GRFS) was higher with the reduced dose compared to the standard dose (60% versus 33%, p = 0.04). In conclusion, reducing PT-Cy total dose to 70 mg/kg is a safe and valid approach for elderly patients and those with cardiac comorbidities underdoing haploidentical HCT with PBSCs and low-dose antithymocyte globulin. The reduced PT-Cy dose was associated with improved hematological count recovery, lower incidence of toxicities, and higher GRFS., (© 2023. The Author(s), under exclusive licence to Springer Nature Limited.)

We describe a 9-year-old boy who developed generalised erythematous lesions 12 months after haematopoietic stem cell transplant (HSCT). Histopathology showed both features of psoriasis and graft-versus-host disease (GVHD). The lesions responded well to secukinumab, suggesting that IL-17A monoclonal antibody might be a treatment option for GVHD., (© 2023 The Australasian College of Dermatologists.)

Introduction: The novel low-dose anti-thymocyte (ATG, 5 mg/kg) plus low-dose post-transplant cyclophosphamide (PTCy, 50 mg/kg) (low-dose ATG/PTCy)-based regimen had promising activity for prevention of graft-versus-host disease (GVHD) in haploidentical-peripheral blood stem cell transplantation (haplo-PBSCT), but its impacts on long-term outcomes remain to be defined., Methods: We performed a large sample, long-term follow-up retrospective study to evaluate its efficacy for GVHD prophylaxis., Results: The study enrolled 260 patients, including 162 with myeloid malignancies and 98 with lymphoid malignancies. The median follow-up time was 27.0 months. For the entire cohort, the cumulative incidences (CIs) of grade II-IV and III-IV acute GVHD (aGVHD) by 180 days were 13.46% (95% CI, 9.64%-17.92%) and 5.77% (95% CI, 3.37%-9.07%); while total and moderate/severe chronic GVHD (cGVHD) by 2 years were 30.97% (95% CI, 25.43%-36.66%) and 18.08% (95% CI, 13.68%-22.98%), respectively. The 2-year overall survival (OS), relapse-free survival (RFS), GVHD-free, relapse-free survival (GRFS), non-relapse mortality (NRM), and CIs of relapse were 60.7% (95% CI, 54.8%-67.10%), 58.1% (95% CI, 52.2%-64.5%), 50.6% (95% CI, 44.8-57.1%), 23.04% (95% CI, 18.06%-28.40%), and 18.09% (95% CI, 14.33%-23.97%, respectively. The 1-year CIs of cytomegalovirus (CMV) and Epstein-Barr virus (EBV) reactivation were 43.46% (95% CI, 37.39%-49.37%) and 18.08% (95% CI, 13.68%-22.98%), respectively. In multivariate analysis, the disease status at transplantation was associated with inferior survivor outcomes for all patients and myeloid and lymphoid malignancies, while cGVHD had superior outcomes for all patients and myeloid malignancies, but not for lymphoid malignancies., Discussion: The results demonstrated that the novel regimen could effectively prevent the occurrence of aGVHD in haplo-PBSCT., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Li, Yang, Cai, Huang, Xu, Qiu, Niu, Zhou, Zhang, Xia, Wei, Shen, Tong, Dong, Wan and Song.)

Traditional conditioning regimens for patients undergoing allogeneic hematopoietic cell transplantation (allo-HCT) provide suboptimal outcomes, especially for older patients and those with comorbidities. We hypothesized that a fractionated myeloablative busulfan dose delivered over an extended period would reduce nonrelapse mortality (NRM) while retaining antileukemic effects. Here, we performed a phase 2 trial for adults with hematological malignancies receiving matched related or unrelated allo-HCT. Participants received busulfan 80 mg/m2 as outpatients on days -20 and -13 before transplant. Fludarabine 40 mg/m2 was administered on days -6 to -3, followed by busulfan dosed to achieve a target area under the curve of 20 000 mol/min for the whole course. The primary end point was day-100 NRM. Seventy-eight patients were included, with a median age of 61 years (range, 39-70 years), who received transplantation for acute leukemia (24%), myelodysplastic syndrome (27%), or myeloproliferative disease/chronic myeloid leukemia (44%). HCT-specific comorbidity index (HCT-CI) was ≥3 in 34 (44%). With a median follow-up of 36.4 months (range, 2.9-51.5), the 100-day, 1-year, and 3-year NRM rates were 3.8%, 8%, and 9.3%, respectively, without a significant difference in age or HCT-CI score. The 1-year and 3-year relapse incidence was 10% and 18%, respectively. The 3-year overall survival was 80%, without a significant difference in age or HCT-CI score and was similar for patients aged >60 years and those aged <60 years as well as for those with HCT-CI ≥3 and HCT-CI <3. Overall, a myeloablative fractionated busulfan regimen has low NRM without an increase in relapse rate, resulting in promising survival, even in older patients or in patients with comorbidities. This trial was registered at www.clinicaltrials.gov as #NCT02861417., (© 2023 by The American Society of Hematology. Licensed under Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0), permitting only noncommercial, nonderivative use with attribution. All other rights reserved.)

Background Aims: Although calcineurin inhibitors (CNIs) have a well-established role in the prevention of graft-versus-host disease (GVHD) after allogeneic hematopoietic cell transplantation (HCT), their use can be limited by significant toxicities, which may result in premature treatment discontinuation. The optimal management of patients with CNI intolerance is unknown. The objective of this study was to determine the effectiveness of corticosteroids as GVHD prophylaxis for patients with CNI intolerance., Methods: This retrospective single-center study included consecutive adult patients with hematologic malignancies who underwent myeloablative peripheral blood allogeneic HCT with anti-thymocyte globulin, CNI, and methotrexate GVHD prophylaxis in Alberta, Canada. Multivariable competing-risks regression was used to compare cumulative incidences of GVHD, relapse, and non-relapse mortality between recipients of corticosteroid versus continuous CNI prophylaxis, and multivariable Cox proportional hazards regression was applied to compare overall survival, relapse-free survival (RFS) and moderate-to-severe chronic GVHD and RFS., Results: Among 509 allogeneic HCT recipients, 58 (11%) patients developed CNI intolerance and were switched to corticosteroid prophylaxis at median 28 days (range 1-53) after HCT. Compared with patients who received continuous CNI prophylaxis, recipients of corticosteroid prophylaxis had significantly greater cumulative incidences of grade 2-4 acute GVHD (subhazard ratio [SHR] 1.74, 95% confidence interval [CI] 1.08-2.80, P = 0.024), grade 3-4 acute GVHD (SHR 3.22, 95% CI 1.55-6.72, P = 0.002), and GVHD-related non-relapse mortality (SHR 3.07, 95% CI 1.54-6.12, P = 0.001). There were no significant differences in moderate-to-severe chronic GVHD (SHR 0.84, 95% CI 0.43-1.63, P = 0.60) or relapse (SHR 0.92, 95% CI 0.53-1.62, P = 0.78), but corticosteroid prophylaxis was associated with significantly inferior overall survival (hazard ratio [HR] 1.77, 95% CI 1.20-2.61, P = 0.004), RFS (HR 1.54, 95% CI 1.06-2.25, P = 0.024), and chronic GVHD and RFS (HR 1.46, 95% CI 1.04-2.05, P = 0.029)., Conclusions: Allogeneic HCT recipients with CNI intolerance are at increased risks of acute GVHD and poor outcomes despite institution of corticosteroid prophylaxis following premature CNI discontinuation. Alternative GVHD prophylaxis strategies are needed for this high-risk population., Competing Interests: Declaration of Competing Interest The authors have no commercial, proprietary or financial interest in the products or companies described in this article., (Copyright © 2023 International Society for Cell & Gene Therapy. Published by Elsevier Inc. All rights reserved.)

Background: Chronic graft-versus-host disease is a severe complication of allogeneic stem cell and bone marrow transplantation. First-line immunosuppressive agents, such as steroids, are used to prevent this disease; however, they have multiple side effects. Therefore, bath psoralen plus ultraviolet-A (PUVA) is an alternative second-line treatment. This study aimed to evaluate the clinical efficacy of bath PUVA for managing chronic graft-versus-host disease., Methods: This retrospective, case-control study included 14 patients with extensive cutaneous chronic graft-versus-host disease, resistant to systemic corticosteroid, treated with bath PUVA. Major and partial responses were defined as clinical improvements of >70% and 50-70%, respectively. We analyzed the graft-versus-host disease clinical presentation and timing after allogeneic stem cell and bone marrow transplantation, bath PUVA doses, background diseases, additional treatments, and adverse effects., Results: We observed eight major (three lichenoid and five sclerodermatoid) and six partial (three lichenoid and three sclerodermatoid) responses after a mean of 28 treatment sessions. After 6 to 25 months, four of the eight patients with sclerodermatoid lesions and all those with lichenoid lesions experienced relapse but responded to additional treatment cycles., Conclusions: Bath PUVA is well-tolerated and effective for extensive cutaneous chronic graft-versus-host disease. It allows rapid tapering of adjuvant immunosuppressants; however, most patients require prolonged maintenance phototherapy., (© 2023 the International Society of Dermatology.)

Capecitabine is a commonly used oral chemotherapeutic agent. Gastrointestinal (GI) side effects are clinically well-known, however, the histopathologic changes have not been comprehensively studied. This study describes the largest case series (8 patients) characterizing the histopathology of capecitabine-induced GI injury. All patients were adults (median age: 64.5 y, range: 61 to 76 y) and there was gender parity. Patients were receiving treatment for malignancies of the colorectum (n=5), breast (n=1), pancreas (n=1), and appendix (n=1). All had GI symptoms, including 7 with diarrhea and abdominal pain and 1 with melena. Five of 8 (63%) showed graft-versus-host disease (GVHD)-like histologic changes in small intestinal and/or colonic biopsies characterized by crypt disarray and dropout, crypt atrophy, dilated crypts lined by attenuated epithelium, and increased crypt apoptosis. Neuroendocrine cell aggregates were present in 4 of 5 cases. Four of 5 showed patchy prominence in lamina propria eosinophils. One patient receiving concomitant radiation therapy had a small intestinal biopsy showing regenerative changes. Two patients had histologically unremarkable biopsies. On follow-up, capecitabine was discontinued or dose-reduced in all patients. Three of 5 patients with a GVHD-like pattern had clinical improvement, whereas 2 died shortly after biopsy. One with regenerative changes also had radiation dose reduction and improved clinically. Two with unremarkable biopsies improved symptomatically. In summary, capecitabine-related GI injury shows a GVHD-like pattern. Knowledge of this is important to confirm the diagnosis as patients typically improve with dose reduction or discontinuation of the drug., Competing Interests: Conflicts of Interest and Source of Funding: The authors have disclosed that they have no significant relationships with, or financial interest in, any commercial companies pertaining to this article., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

Chronic graft-versus-host disease (cGVHD) is a major cause of morbidity and mortality after allogeneic hematopoietic stem cell transplantation. Mature donor T cells within the graft contribute to severe damage of thymic epithelial cells (TECs), which are known as key mediators in the continuum of acute GVHD (aGVHD) and cGVHD pathology. Mesenchymal stromal cells (MSCs) are reportedly effective in the prevention and treatment of cGVHD. In our previous pilot clinical trial in patients with refractory aGVHD, the incidence and severity of cGVHD were decreased, along with an increase in levels of blood signal joint T-cell receptor excision DNA circles after MSCs treatment, which indicated an improvement in thymus function of patients with GVHD, but the mechanisms leading to these effects remain unknown. Here, we show in a murine GVHD model that MSCs promoted the quantity and maturity of TECs as well as elevated the proportion of Aire-positive medullary TECs, improving both CD4+CD8+ double-positive thymocytes and thymic regulatory T cells, balancing the CD4:CD8 ratio in the blood. In addition, CCL25-CCR9 signaling axis was found to play an important role in guiding MSC homing to the thymus. These studies reveal mechanisms through which MSCs ameliorate cGVHD by boosting thymic regeneration and offer innovative strategies for improving thymus function in patients with GVHD., (© 2023 by The American Society of Hematology. Licensed under Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0), permitting only noncommercial, nonderivative use with attribution. All other rights reserved.)

Graft-versus-host disease (GVHD) is a common and important complication of allogenic hematopoietic cell transplantation. The cardinal histologic feature of GVHD in the gastrointestinal tract is the presence of apoptotic bodies. To date, no study has evaluated the pathologic characteristics of gallbladder GVHD (GB-GVHD). In this study, we sought to describe their clinicopathologic features in a cohort of pediatric patients and compared them to a control group composed of 10 and 15 recent cases of acute and chronic cholecystitis, respectively. A total of 6 GB-GVHD cases were included, 5 cholecystectomies and 1 autopsy case(s), presenting in 2 boys and 4 girls, with a mean age of 6.7 years (1.5-18.6). The median days post-transplant to presentation was 261 (40-699), and all cases had GVHD involving other organs. GB-GVHD compared to the control groups was significantly associated with a younger age (P = .019), presence of apoptotic bodies and higher number of apoptotic bodies in 10 continuous mucosal folds and in 100 and 500 epithelial cells (all P < .001), and increased number of intraepithelial lymphocytes per 100 epithelial cells (P < .001). All patients were treated for GVHD with half of them achieving treatment response. Besides the autopsy case, all patients are alive with a median follow-up time of 45 months (4-212). The cause of death for the autopsy case was sepsis due to Pseudomonas aeruginosa. In our experience, the presence of both increased apoptotic bodies and intraepithelial lymphocytes in the gallbladder of hematopoietic cell transplantation patients should raise concern for GB-GVHD., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Background: 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 (GvHD). 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 GvHD., Methods: 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., Results: 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 GvHD, 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 GvHD, 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 GvHD., Conclusion: Our findings suggest a possible relationship between the influence of acute GvHD 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 GvHD., Competing Interests: Declaration of Competing Interest The authors declare that they have no competing interests., (Copyright © 2023. Published by Elsevier B.V.)

Few patients with nonfavorable risk (NFR) acute leukemia and myeloid dysplasia syndrome (AL/MDS) undergo allogeneic transplantation (HCT). We assessed whether this could be improved by integrating HCT/leukemia care and the use of haploidentical donors. Of 256 consecutive patients aged <75 years who received initial therapy at our center for NFR AL/MDS from 2016 to 2021, 147 (57%) underwent planned HCT (70% for patients aged <60 years). In the logistic regression analysis, age (OR 1.50 per 10-year increment; P < .001) and race (Black vs White [OR 2.05; P = .023]) were significant factors for failure to receive HCT. Reasons for no HCT included comorbidities (37%), poor KPS, lack of caregiver support, refractory malignancy (19% each), and patient refusal (17%). Lack of donor or insurance were rarely cited (3% each). In older patients (≥60 years), comorbidities (49 vs 15%; P < .001) and KPS (25% vs 10%; P = .06) were more common, and lack of caregivers was less common (13% vs 30%; P = .031). In Black vs White patients, lack of caregivers (37% vs 11%; P = .002) was more frequent. The median time from initial treatment to HCT was 118 days and was similar for Black and White patients. Landmark analysis showed that HCT within 6 months of the initial treatment produced better survival. Multivariable analysis showed that HCT resulted in a significant survival benefit (HR 0.60; P = .020). With the above approach, most of the currently treated patients aged <75 years can access planned HCT. Black patients remain at greater risk of not receiving HCT., (© 2023 by The American Society of Hematology. Licensed under Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0), permitting only noncommercial, nonderivative use with attribution. All other rights reserved.)

Graft-versus-host disease (GVHD) is the major factor limiting the widespread use of potentially curative allogeneic hematopoietic stem cell transplant (allo-HSCT). Chronic GVHD is characterized by the activation of alloreactive donor immune cells, especially B- and T-cells, leading to tissue damage and pathogenic fibrosis. In this study, we used highly specific next-generation inhibitors of ITK (PCYC-274), BTK (PCYC-804), and ibrutinib-like BTK/ITK inhibitors (PCYC-914 and PCYC-401) in the B10.D2 → BALB/C model of murine sclerodermatous cGVHD. From the third week onward, allogeneic recipients in each group of respective Tec kinase inhibitors were treated three times weekly with inhibitors at doses of 10 and 30 mg/kg or with saline control via oral gavage. Overall, we found that selective BTK inhibition was less effective than combined ITK/BTK or ITK inhibition in lengthening survival and reducing symptoms of cGVHD. ITK inhibition was most efficacious, with PCYC-274 and PCYC-401 demonstrating a nearly 50 percent reduction in GVHD scoring even at the 10 mg/kg dose, while 30 mg/kg of these compounds almost completely ameliorated GVHD symptomology. BTK/ITK and ITK-treated mice showed significant reductions in overall pathology. Significant reductions in dermal thickness and fibrosis were shown for all treatment groups. There was evidence of mixed Th1 and Th2 cytokine profiles in the skin of mice with dermal cGVHD, as both IFN-gamma and IL-4 were upregulated in the allogeneic control group, while kinase inhibition significantly reduced levels of these cytokines. Using an in vitro model of T-cell polarization, Th1 cell production of TNF-alpha and IFN-gamma were partially blocked by ITK. Th2 cell production of IL-4 was almost completely blocked synergistically by ITK and BTK inhibition. BTK-specific inhibition was unable to block either Th1 or Th2 cytokine production. Taken together, these results confirm previous reports that ITK-focused inhibition inhibits Th1 and Th2 cells. Additionally, the compound's effects on T-cell proliferation were tested by CFSE assay. Pure ITK inhibition was most effective at blocking T-cell proliferation, with no proliferation in PCYC-274-treated cells even at 0.1uM. PCYC-401 and PCYC-914 showed some inhibition at lower doses, with complete inhibition evident at 10uM. PCYC-804 was only partially able to block proliferation even at 10uM. In conclusion, we observed substantial benefit for differential inhibition of Tec kinases in GVHD, with ITK being most efficacious and Th1 cells being more resistant to inhibition, matching the previously reported findings of a Th2 to Th1 selective pressure in cells treated with ibrutinib. Our data warrants the further development of ITK and ITK/BTK inhibitors with specific inhibitory ratios to improve the treatment of GVHD and other T-cell mediated diseases., (© 2023. The Author(s), under exclusive licence to Springer Nature Limited.)

T cells are the central drivers of many inflammatory diseases, but the repertoire of tissue-resident T cells at sites of pathology in human organs remains poorly understood. We examined the site-specificity of T cell receptor (TCR) repertoires across tissues (5 to 18 tissues per patient) in prospectively collected autopsies of patients with and without graft-versus-host disease (GVHD), a potentially lethal tissue-targeting complication of allogeneic hematopoietic cell transplantation, and in mouse models of GVHD. Anatomic similarity between tissues was a key determinant of TCR repertoire composition within patients, independent of disease or transplant status. The T cells recovered from peripheral blood and spleens in patients and mice captured a limited portion of the TCR repertoire detected in tissues. Whereas few T cell clones were shared across patients, motif-based clustering revealed shared repertoire signatures across patients in a tissue-specific fashion. T cells at disease sites had a tissue-resident phenotype and were of donor origin based on single-cell chimerism analysis. These data demonstrate the complex composition of T cell populations that persist in human tissues at the end stage of an inflammatory disorder after lymphocyte-directed therapy. These findings also underscore the importance of studying T cell in tissues rather than blood for tissue-based pathologies and suggest the tissue-specific nature of both the endogenous and posttransplant T cell landscape.

Jarosch et al. 1 have deeply characterized immune cell infiltrates in gastrointestinal (GI) biopsies from individuals with GI graft-versus-host disease (GI-GvHD) using single-cell RNA sequencing and ChipCytometry. Individuals with severe GI-GvHD demonstrated increased clonally expanded cytotoxic CD8 T cells in GI biopsies., Competing Interests: Declaration of interests R.R.J. has served as a consultant or advisory board member for Merck, Microbiome DX, Karius, MaaT Pharma, LISCure, Seres, Kaleido, and Prolacta and has received patent license fees or stock options from Seres and Kaleido., (Copyright © 2023 The Author(s). Published by Elsevier Inc. All rights reserved.)

Acute graft-versus-host disease (aGvHD) is a significant complication after allogeneic hematopoietic stem cell transplantation (aHSCT), but major factors determining disease severity are not well defined yet. By combining multiplexed tissue imaging and single-cell RNA sequencing on gastrointestinal biopsies from aHSCT-treated individuals with fecal microbiome analysis, we link high microbiome diversity and the abundance of short-chain fatty acid-producing bacteria to the sustenance of suppressive regulatory T cells (Tregs). Furthermore, aGvHD severity strongly associates with the clonal expansion of mainly CD8 T cells, which we find distributed over anatomically distant regions of the gut, persistent over time, and inversely correlated with the presence of suppressive Tregs. Overall, our study highlights the pathophysiological importance of expanded CD8 T cell clones in the progression of aGvHD toward more severe clinical manifestations and strongly supports the further development of microbiome interventions as GvHD treatment via repopulation of the gut Treg niche to suppress inflammation., Competing Interests: Declaration of interests D.H.B. is a co-founder of STAGE Cell Therapeutics GmbH (now Juno Therapeutics/Bristol Myers Squibb) and T Cell Factory B.V. (now Kite/Gilead). D.H.B. has a consulting contract with and receives sponsored research support from Juno Therapeutics/BMS. H.P. is a consultant for Gilead, AbbVie, Pfizer, Novartis, Neovii, Janssen-Cilag, Servier, and Bristol Myers Squibb. H.P. has received research funding from Bristol Myers Squibb. E.H. is a consultant of Maat Pharma, PharmaBiome, Novartis, Neovii, and Medac., (Copyright © 2023 The Author(s). Published by Elsevier Inc. All rights reserved.)

Objective: The aim of this study was to elaborate a specific protocol for the assessment and early identification of skin lesions in pediatric patients with Fanconi anemia undergoing hematopoietic stem cell transplantation., Methods: This is a longitudinal, retrospective, and descriptive study. The medical records of 136 pediatric patients with Fanconi anemia who underwent hematopoietic stem cell transplantation between 2008 and 2018 at the Clinical Hospital of the Federal University of Paraná were reviewed. A specific protocol was created for data collection, which included age, sex, skin color, age at diagnosis of Fanconi anemia, transplantation data, family history of consanguinity, and pre- and post-transplant complications. In addition, the data included the presence of graft-versus-host disease of the skin and other organs, its classification, type of lesion, location, and also skin lesions not related to graft-versus-host disease., Results: Among the skin manifestations in pre-transplant period, café-au-lait spots stood out (32.4%). At least one organ was affected by graft-versus-host disease in 55.1% of patients; the most common involvement being the mouth, followed by the skin. Rash and erythema were the most frequently observed cutaneous manifestations of graft-versus-host disease., Conclusion: A high prevalence of cutaneous manifestations of the disease was observed, as well as cutaneous manifestations of graft-versus-host disease. The protocol developed gathers relevant and standardized information for the follow-up of patients with Fanconi anemia undergoing hematopoietic stem cell transplantation, ensuring greater reliability of the information, and its implementation will allow the prospective evaluation of patients.

Objective: To evaluate the clinical outcomes and safety of haploidentical hematopoietic stem cell transplantation (haplo-HSCT) using a conditioning regimen based on total body irradiation (TBI) and rabbit anti-human thymocyte globulin (rATG) in the management of chemotherapy-resistant advanced peripheral T-cell lymphoma (PTCL) . Methods: Clinical data of 11 patients with chemotherapy-resistant advanced PTCL who underwent haplo-HSCT with a TBI+rATG-based conditioning regimen at the Department of Hematology, Shanghai Liquan Hospital and Shanghai Zhaxin Integrated Traditional Chinese and Western Medicine Hospital, from September 2019 to December 2022 were retrospectively analyzed. Results: ①Among the 11 patients (six males and five females), with a median age of 40 years (range: 22-58 years), there were six cases of PTCL, not otherwise specified (PTCL-NOS), three cases of angioimmunoblastic T-cell lymphoma (AITL), one case of large-cell transformation of mycosis fungoides (MF-LCT), and one case of T-cell large granular lymphocytic leukemia (T-LGLL). According to the Lugano staging system, all patients were in stage Ⅲ or Ⅳ, and eight patients had B symptoms. Before transplantation, the median number of prior lines of chemotherapy was 4 (range: 2-10), and all patients had progressive disease (PD). The median time from diagnosis to transplantation was 17 months (range: 6-36 months). ②The conditioning regimen consisted of a TBI dose of 10 Gy, administered at 2 Gy on day -8 and 4 Gy from day -7 to day -6, rATG was administered at a daily dose of 2.5 mg/kg from day -5 to day -2. Etoposide (VP-16) was given at a dose of 15 mg/kg/d from day -5 to day -4, while cyclophosphamide (CTX) was administered at a dose of 50 mg/kg/d from day -3 to day -2. In patients with central nervous system involvement, etoposide and cyclophosphamide were replaced with thiotepa (TT) at a dose of 5 mg/kg/d from day -5 to day -4. Additionally, cytarabine (Ara-C) was added at a dose of 2.0 g/m(2) twice a day from day -3 to day -2 into the conditioning. ③Successful engraftment was achieved in all patients, with a median time to neutrophil engraftment of 14.5 d (range: 11-16 d) and a median time to platelet engraftment of 13 days (range: 8-18 days). Acute graft-versus-host disease (aGVHD) occurred in one patient (grade Ⅰ-Ⅱ), and another patient experienced grade Ⅲ-Ⅳ aGVHD. Among the eight survivors, four developed chronic GVHD (cGVHD). ④Post-transplantation, nine patients achieved complete response (CR). ⑤Hematopoietic suppression occurred in all patients after conditioning, with three experiencing diarrhea, four developing mucositis, three exhibiting elevated transaminase/bilirubin levels, and seven developing infectious complications. These non-hematologic adverse events were effectively managed. ⑥At one year post-transplantation, the non-relapse mortality (NRM) was (22.5±14.0) %, the cumulative incidence of relapse (CIR) was (20.2±12.7) %, and overall survival (OS) rate was (72.7±13.4) %, and disease-free survival (DFS) rate was (63.6±14.5) % . Conclusion: TBI+rATG-based conditioning regimen for haplo-HSCT is an effective and safe treatment approach for patients with chemotherapy-resistant advanced PTCL.

Histomorpholgy is one of the mainstays of acute Graft-versus-host disease (GvHD) diagnosis. However, concerns about reproducibility and the most appropriate grading system question its usefulness. Our aim was to assess histomorphological parameters and previously reported grading systems for GvHD regarding reproducibility and validity. Moreover, we propose that sum scores, derived by combining separately scored morphological parameters into a total score, might provide a simplified but equally effective means to grade GvHD. A total of 123 colon biopsies were assessed across four pathologists for intestinal GvHD using a Round-Robin test and results were correlated with clinical findings. Interobserver reproducibility was high for histological parameters that were evaluated as indicators of acute GvHD. Published grading systems were moderately reproducible (ICC 0.679-0.769) while simplified sum scores, in comparison, showed better interrater reliability (ICC 0.818-0.896). All grading systems and sum scores were associated with clinical signs of GvHD and in part with therapy response and survival. However, they were not able to stratify patients according to the clinical severity of GvHD. In a hot-spot analysis 1 crypt apoptotic body (CAB) in 10 crypts was a reasonable cut-off value for minimal diagnostic criteria of GvHD. In conclusion, histology can contribute to the diagnosis of GvHD and is reproducible. Published grading systems are able to reflect clinical findings as are simplified sum scores, which showed improved reproducibility and might be easier to handle as they are based on adding up histological parameters rather than transferring histological findings into a separate grading system. Sum scores will have to be further tested in a prospective setting., (© 2023. The Author(s).)

Background: The gastrointestinal tract is the second most involved organ for graft-versus-host disease where involvement of the small intestine is present in 50% of the cases. Therefore, the use of a non-invasive investigation i.e., video capsule endoscopy (VCE) seems ideal in the diagnostic work-up, but this has never been systematically evaluated before., Objective: The aim of this systematic review was to determine the efficacy and safety of VCE, in comparison with conventional endoscopy in patients who received hematopoietic stem cell transplantation., Method: Databases searched were PubMed, Scopus, EMBASE, and Cochrane CENTRAL. All databases were searched from their inception date until June 17, 2022. The search identified 792 publications, of which 8 studies were included in our analysis comprising of 232 unique patients. Efficacy was calculated in comparison with the golden standard i.e., histology. Risk of bias assessment was performed using the Quality Assessment of Diagnostic Accuracy Studies-2 tool., Results: The pooled sensitivity was higher for VCE at 0.77 (95% CI: 0.60-0.89) compared to conventional endoscopy 0.62 (95% CI: 0.47-0.75) but the difference was not statistically significant ( p  = 0.155, Q  = 2.02). Similarly, the pooled specificity was higher for VCE at 0.68 (95% CI: 0.46-0.84) than for conventional endoscopy at 0.58 (95% CI: 0.40-0.74) but not statistically significant ( p  = 0.457, Q  = 0.55). Moreover, concern for adverse events such as intestinal obstruction or perforation was not justified since none of the capsules were retained in the small bowel and no perforations occurred in relation to VCE. A limitation to the study is the retrospective approach seen in 50% of the studies., Conclusion: The role of video capsule endoscopy in diagnosing or dismissing graft-versus-host disease is not yet established and requires further studies. However, the modality appears safe in this cohort.

Steroid-refractory chronic graft-versus-host disease (cGVHD) after allogeneic transplant remains a significant cause of morbidity and mortality. Abatacept is a selective costimulation modulator, used for the treatment of rheumatologic diseases, and was recently the first drug to be approved by the US Food and Drug Administration for the prophylaxis of acute graft-versus-host disease. We conducted a phase 2 study to evaluate the efficacy of abatacept in steroid-refractory cGVHD. The overall response rate was 58%, seen in 21 out of 36 patients, with all responders achieving a partial response. Abatacept was well tolerated with few serious infectious complications. Immune correlative studies showed a decrease in interleukin -1α (IL-1α), IL-21, and tumor necrosis factor α as well as decreased programmed cell death protein 1 expression by CD4+ T cells in all patients after treatment with abatacept, demonstrating the effect of this drug on the immune microenvironment. The results demonstrate that abatacept is a promising therapeutic strategy for the treatment of cGVHD. This trial was registered at www.clinicaltrials.gov as #NCT01954979., (© 2023 by The American Society of Hematology.)

Objective: The purpose of this study was to assess the safety and efficacy of a second allogeneic hematopoietic stem cell transplantation (allo-HSCT) with reduced-intensity conditioning (RIC) in patients with hematological malignancies who had relapsed after the first allo-HSCT. Methods: Between April 2018 and June 2021, 44 patients with hematological malignancies (B-ALL 23, T-ALL/T-LBL 4, AML15, and MDS 2) were enrolled and retrospectively examined. Unrelated donors ( n =12) or haploidentical donors ( n =32) were used. Donors were replaced in all patients for the second allo-HSCT. Hematological and immunological germline predisposition genes and hematopoietic and immune function tests were used to select the best-related donor. Total body irradiation (TBI) /fludarabine (FLU) -based ( n =38), busulfan (BU) /FLU-based ( n =4), total marrow irradiation (TMI) /FLU-based ( n =1), and BU/cladribine-based ( n =1) were the RIC regimens used. For graft versus host disease (GVHD) prevention, cyclosporine, mycophenolate mofetil, short-term methotrexate, and ATG were used. Eighteen (40.9%) of 44 patients with gene variations for which targeted medications are available underwent post-transplant maintenance therapy. Results: The median age was 25 years old (range: 7-55). The median interval between the first and second HSCT was 19.5 months (range: 6-77). Before the second allo-HSCT, 33 (75%) of the patients were in complete remission (CR), whereas 11 (25%) were not. All patients had long-term engraftment. The grade Ⅱ-Ⅳ GVHD and severe acute GVHD rates were 20.5% and 9.1%, respectively. Chronic GVHD was found in 20.5% of limited patterns and 22.7% of severe patterns. CMV and EBV reactivation rates were 29.5% and 6.8%, respectively. Hemorrhage cystitis occurred in 15.9% of cases, grade Ⅰ or Ⅱ. The 1-yr disease-free survival (DFS), overall survival (OS), and cumulative recurrence incidence (RI) rates of all patients were 72.5% (95% CI , 54.5%-84.3%), 80.6% (95% CI , 63.4%-90.3%), and 25.1% (95% CI , 13.7%-43.2%), respectively, with a median follow-up of 14 (2-39) months. There were eight deaths (seven relapses and one infection). The rate of non-relapse mortality (NRM) was only 2.3%. The CR patients' 1-yr RI rate was significantly lower than the NR patients (16.8% vs 48.1%, P =0.026). The DFS rate in CR patients was greater than in NR patients, although there was no statistical difference (79.9% vs 51.9%, P =0.072). Univariate analysis revealed that CR before the second allo-HSCT was an important prognostic factor. Conclusion: With our RIC regimens, donor change, and post-transplant maintenance therapy, the second allo-HSCT in relapsed hematological malignancies after the first allo-HSCT is a safe and effective treatment with high OS and DFS and low NRM and relapse rate. The most important factor influencing the prognosis of the second allo-HSCT is the patient's illness condition before the transplant.

Hematopoietic cell transplantation (HCT) is the only readily available cure for many life-threatening pediatric nonmalignant diseases (NMD), but most patients lack a matched related donor and are at higher risk for graft-versus-host disease (GVHD). Use of abatacept (Aba) to target donor T-cell activation has been safe and effective in preventing GVHD after unrelated donor (URD) HCT for malignant diseases (Aba2 trial). Our primary objective was to evaluate the tolerability of Aba added to standard GVHD prophylaxis (cyclosporine and mycophenolate mofetil) in pediatric patients with NMD undergoing URD HCT. In this single-arm, single-center phase 1 trial, 10 patients receiving reduced intensity or nonmyeloablative conditioning underwent URD HCT. Immune reconstitution was assessed longitudinally via flow cytometry and compared to pediatric patients on Aba2. Nine patients successfully engrafted, with 1 primary graft rejection in the setting of inadequate cell dose; secondary graft rejection occurred in 1 patient with concurrent cytomegalovirus viremia. Two deaths occurred, both unrelated to Aba. One patient developed probable posttransplant lymphoproliferative disease, responsive to rituximab and immune suppression withdrawal. No patients developed severe acute or chronic GVHD, and 8 patients were off systemic immunosuppression at 1 year. Immune reconstitution did not appear to be impacted by Aba, and preservation of naïve relative to effector memory CD4+ T cells was seen akin to Aba2. Thus, 4 doses of Aba were deemed tolerable in pediatric patients with NMD following URD HCT, with encouraging preliminary efficacy and supportive immune correlatives in this NMD cohort., (© 2023 by The American Society of Hematology. Licensed under Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0), permitting only noncommercial, nonderivative use with attribution. All other rights reserved.)

Chronic graft-versus-host disease (cGVHD) presents with dermal inflammation and fibrosis. We investigated the characteristics of extracellular vesicles (EVs) obtained from cGVHD patients, and their potential effects on human dermal fibroblast (NHDF) cells. The anti-inflammatory and anti-fibrotic effects of placental EVs were also explored given their known anti-inflammatory properties. Fourteen cGVHD patients' EVs contained higher levels of fibrosis-related proteins, TGFβ and α-smooth muscle actin (αSMA), compared to EVs from thirteen healthy subjects. The exposure of NHDF cells to the patients' EVs increased the NHDF cells' TGFβ and αSMA expressions. Placental EVs derived from placental-expanded cells (PLX) (Pluri Inc.) and human villous trophoblast (HVT) cells expressing the mesenchymal markers CD29, CD73, and CD105, penetrated into both the epidermal keratinocytes (HACATs) and NHDF cells. Stimulation of the HACAT cells with cytokine TNFα/INFγ (0.01-0.1 ng/µL) reduced cell proliferation, while the addition of placental EVs attenuated this effect, increasing and normalizing cell proliferation. The treatment of NHDF cells with a combination of TGFβ and placental HVT EVs reduced the stimulatory effects of TGFβ on αSMA production by over 40% ( p = 0.0286). In summary, EVs from patients with cGVHD can serve as a biomarker for the cGVHD state. Placental EVs may be used to regulate dermal inflammation and fibrosis, warranting further investigation of their therapeutic potential.

Posttransplantation cyclophosphamide (PTCy), given on days +3 and +4, reduces graft-versus-host disease (GVHD) after allogeneic hematopoietic cell transplantation (HCT), but its immunologic underpinnings are not fully understood. In a T-cell-replete, major histocompatibility complex-haploidentical murine HCT model (B6C3F1→B6D2F1), we previously showed that PTCy rapidly induces suppressive mechanisms sufficient to prevent GVHD induction by non-PTCy-exposed donor splenocytes infused on day +5. Here, in PTCy-treated mice, we found that depleting Foxp3+ regulatory T cells (Tregs) in the initial graft but not the day +5 splenocytes did not worsen GVHD, yet depleting Tregs in both cellular compartments led to fatal GVHD induced by the day +5 splenocytes. Hence, Tregs were necessary to control GVHD induced by new donor cells, but PTCy's impact on Tregs appeared to be indirect. Therefore, we hypothesized that myeloid-derived suppressor cells (MDSCs) play a complementary role. Functionally suppressive granulocytic and monocytic MDSCs were increased in percentages in PTCy-treated mice, and MDSC percentages were increased after administering PTCy to patients undergoing HLA-haploidentical HCT. PTCy increased colony-stimulating factors critical for MDSC development and rapidly promoted the generation of MDSCs from bone marrow precursors. MDSC reduction via anti-Gr1 treatment in murine HCT did not worsen histopathologic GVHD but resulted in decreased Tregs and inferior survival. The clinical implications of these findings, including the potential impact of expanded MDSCs after PTCy on engraftment and cytokine release syndrome, remain to be elucidated. Moreover, the indirect effect that PTCy has on Tregs, which in turn play a necessary role in GVHD prevention by initially transplanted or subsequently infused T cells, requires further investigation., (Licensed under Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0), permitting only noncommercial, nonderivative use with attribution. All other rights reserved.)