Autophagy differentially regulates tissue tolerance of distinct target organs in graft-versus-host disease models.

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.

[Risk prediction and function evaluation by T-cell epitope model and expression model of HLA-DPB1 mismatching in unrelated-donor hematopoietic stem cell transplantations].

Objective: To evaluate the risk prediction and assessment function of HLA-DPB1 T-cell epitope (TCE) model and expression model in human leukocyte antigen (HLA)-matched unrelated hematopoietic stem cell transplantation (MUD-HSCT) with HLA-DPB1 mismatching. Methods: A total of 364 (182 pairs) potential MUD-HSCT donors and recipients confirmed by HLA high-resolution typing in Shaanxi Blood Center from 2016 to 2019 were analyzed retrospectively. Of the 182 recipients, there were 121 males and 61 females with an average age of (26.3±14.2) years. Of the 182 donors, there were 148 males and 34 females with an average age of (33.7±7.5) years. Polymerase chain reaction-sequence-based typing (PCR-SBT), next-generation sequencing (NGS) and polymerase chain reaction-sequence specific oligonucleotide probe (PCR-SSO) based on LABScan®3D platform were used for high-resolution typing of HLA-A, B, C, DRB1, DQB1, DPB1 gene, and PCR-SBT was used for single nucleotide polymorphism (SNP) typing. TCE model and expression model were used to predict and evaluate the HLA-DPB1 mismatch pattern and acute graft-versus-host-disease (aGVHD) risk. Results: A total of 26 HLA-DPB1 alleles and their 3'-UTR rs9277534 SNP genotypes were detected in this study population, and two new alleles HLA-DPB1*1052∶01 and HLA-DPB1*1119∶01 were found and officially named. The overall mismatch rate of HLA-DPB1 in MUD-HSCT donors and recipients was 90.66% (165/182). In TCE model, the HLA-DPB1 mismatch rates of permissible mismatch (PM) and non-permissible mismatch (non-PM) were 47.80% (87/182) and 42.86% (78/182), respectively. The non-PM in GvH direction was 13.73% (25/182), and which in HvG direction was 29.12% (53/182). A total of 73 pairs of donors and recipients in TCE model met the evaluation criteria of expression model. Among of TCE PM group, recipient DP5 mismatches accounted for 34.25% (25/73) were predicted as aGVHD high risk according to expression model. For the TCE non-PM group, both the recipient DP2 mismatches of 6.85% (5/73) and recipient DP5 mismatches of 10.86% (8/73) were predicted to be at high risk for aGVHD. Risk prediction by TCE model and expression model was 27.27% concordant and 16.97% unconcordant. Conclusions: TCE model and expression model are effective tools to predict aGVHD risk of MUD-HSCT. Comprehensive application of the two models is helpful to the hierarchical assessment of HSCT risk.

A genome-wide association study on hematopoietic stem cell transplantation reveals novel genomic loci associated with transplant outcomes.

Introduction: Data on genomic susceptibility for adverse outcomes after hematopoietic stem cell transplantation (HSCT) for recipients are scarce. Methods: We performed a genome wide association study (GWAS) to identify genes associated with survival/mortality, relapse, and severe graft-versus-host disease (sGvHD), fitting proportional hazard and subdistributional models to data of n=1,392 recipients of European ancestry from three centres. Results: The single nucleotide polymorphism (SNP) rs17154454, intronic to the neuronal growth guidant semaphorin 3C gene (SEMA3C), was genome-wide significantly associated with event-free survival (p=7.0x10-8) and sGvHD (p=7.5x10-8). Further associations were detected for SNPs in the Paxillin gene (PXN) with death without prior relapse or sGvHD, as well as for SNPs of the Plasmacytoma Variant Translocation 1 gene (PVT1, a long non-coding RNA gene), the Melanocortin 5 Receptor (MC5R) gene and the WW Domain Containing Oxidoreductase gene (WWOX), all associated with the occurrence of sGvHD. Functional considerations support the observed associations. Discussion: Thus, new genes were identified, potentially influencing the outcome of HSCT.

Lipocalin-2 expression identifies an intestinal regulatory neutrophil population during acute graft-versus-host disease.

Acute graft-versus-host disease (aGVHD) is a life-threatening complication of allogeneic hematopoietic cell transplantation (allo-HCT), for which therapeutic options are limited. Strategies to promote intestinal tissue tolerance during aGVHD may improve patient outcomes. Using single-cell RNA sequencing, we identified a lipocalin-2 (LCN2)-expressing neutrophil population in mice with intestinal aGVHD. Transfer of LCN2-overexpressing neutrophils or treatment with recombinant LCN2 reduced aGVHD severity, whereas the lack of epithelial or hematopoietic LCN2 enhanced aGVHD severity and caused microbiome alterations. Mechanistically, LCN2 induced insulin-like growth factor 1 receptor (IGF-1R) signaling in macrophages through the LCN2 receptor SLC22A17, which increased interleukin-10 (IL-10) production and reduced major histocompatibility complex class II (MHCII) expression. Transfer of LCN2-pretreated macrophages reduced aGVHD severity but did not reduce graft-versus-leukemia effects. Furthermore, LCN2 expression correlated with IL-10 expression in intestinal biopsies in multiple cohorts of patients with aGVHD, and LCN2 induced IGF-1R signaling in human macrophages. Collectively, we identified a LCN2-expressing intestinal neutrophil population that reduced aGVHD severity by decreasing MHCII expression and increasing IL-10 production in macrophages. This work provides the foundation for administration of LCN2 as a therapeutic approach for aGVHD.

Association between CYP3A4, CYP3A5 and ABCB1 genotype and tacrolimus treatment outcomes among allogeneic HSCT patients.

Aim: Successful treatment with tacrolimus to prevent graft versus host disease (GVHD) and minimize tacrolimus-related toxicities among allogeneic hematopoietic cell transplantation (alloHCT) recipients is contingent upon quickly achieving and maintaining concentrations within a narrow therapeutic range. The primary objective was to investigate associations between CYP3A4, CYP3A5 or ABCB1 genotype and the proportion of patients that attained an initial tacrolimus goal concentration following initiation of intravenous (iv.) and conversion to oral administration. Materials & methods: We retrospectively evaluated 86 patients who underwent HLA-matched (8/8) related donor alloHCT and were prescribed a tacrolimus-based regimen for GVHD prophylaxis. Results & conclusion: The findings of the present study suggests that CYP3A5 genotype may impact attainment of initial therapeutic tacrolimus concentrations with oral administration in alloHCT recipients.

Interferon regulatory factor 4 plays a pivotal role in the development of aGVHD-associated colitis.

Interferon regulatory factor 4 (IRF4) is a master transcription factor that regulates T helper cell (Th) differentiation. It interacts with the Basic leucine zipper transcription factor, ATF-like (BATF), depletion of which in CD4+ T cells abrogates acute graft-versus-host disease (aGVHD)-induced colitis. Here, we investigated the immune-regulatory role of Irf4 in a mouse model of MHC-mismatched bone marrow transplantation. We found that recipients of allogenic Irf4-/- CD4+ T cells developed less GVHD-related symptoms. Transcriptome analysis of re-isolated donor Irf4-/- CD4+ T helper (Th) cells, revealed gene expression profiles consistent with loss of effector T helper cell signatures and enrichment of a regulatory T cell (Treg) gene expression signature. In line with these findings, we observed a high expression of the transcription factor BTB and CNC homolog 2; (BACH2) in Irf4-/- T cells, which is associated with the formation of Treg cells and suppression of Th subset differentiation. We also found an association between BACH2 expression and Treg differentiation in patients with intestinal GVHD. Finally, our results indicate that IRF4 and BACH2 act as counterparts in Th cell polarization and immune homeostasis during GVHD. In conclusion, targeting the BACH2/IRF4-axis could help to develop novel therapeutic approaches against GVHD.

Reduced human leukocyte antigen mismatching is associated with more favourable outcomes after unrelated donor haematopoietic stem cell transplantation.

The patient-donor human leukocyte antigen (HLA) match remains the most important prognostic factor for successful unrelated donor haematopoietic stem cell transplantation (UD-HSCT). This single-centre study comprised 125 adult patients with malignant haematological diseases undergoing their first UD-HSCT. The primary goal of this study was to validate the impact of HLA matching on HSCT outcomes, specifically at the HLA-DPB1 and HLA-DRB3/4/5 loci. A multivariable Cox regression analysis with a backward selection algorithm was employed to assess the associations of selected prognostic factors with outcomes after UD-HSCT. Any HLA locus mismatch was found to be associated with an increased incidence of grade II-IV acute graft versus host disease (aGvHD) at 100 days (p = .031; hazard ratio [HR] 1.935) and 6 months (p = .004; HR 2.284) after HSCT. The results of the following analyses also confirmed the strong impact of HLA-DPB1-only mismatch on the incidence of grade II-IV aGvHD at 100-day (p = .006; HR 2.642) as well as at 6-month (p = .007; HR 2.401) time periods. The HLA-DPB1-only mismatch was also shown to be statistically significantly associated with lower relapse incidence (p = .034; HR 0.333). The impact of the HLA-DRB3/4/5 mismatch on outcomes was inconclusive, though the two and more HLA-DPB1 + DRB3/4/5-only mismatches showed a trend towards worse outcomes than a single mismatch. Based on our findings and those of more comprehensive studies, the extended HLA loci typing of patients and donors is suggested to avoid unexpected HLA mismatches during the UD selection.

Clonal hematopoiesis of a novel dic(18;20) clone following allogeneic hematopoietic stem cell transplantation.

A 55-year-old man in first complete remission of acute myeloid leukemia with a normal karyotype underwent allogeneic hematopoietic stem cell transplantation from a human-leukocyte-antigen-matched sibling. Bone marrow examination on day 28 confirmed complete remission, but G-banding analysis revealed a novel chromosomal abnormality, including dic(18;20)(p11.2;q11.2). The patient developed moderate chronic graft-versus-host disease on day 174, and the abnormal clones identified by dic(18;20) significantly increased after that point. Chimerism testing repeatedly confirmed complete donor type. Although next-generation sequencing showed no clonal hematopoiesis-related gene mutations, copy number analysis of the donor and the recipient revealed copy number deletion of 18p, 18q, and 20q. The patient has maintained remission for more than 2 years to date without developing a hematologic neoplasm or cytopenia. The distinctive clonal hematopoiesis with a dicentric chromosome seemed to have undergone the breakage-fusion-bridge cycle, which could cause the complex events of deletion, amplification, and inversion. These copy number alterations might have increased the number of clones with growth advantage, and the highly inflammatory environment in the recipient due to graft-versus-host disease might have contributed to the clonal selection.

A retrospective analysis to evaluate if KIR B haplotype donors associate with a reduced risk of relapse in patients with haematological malignancies following haploidentical transplantation at the Blood and Bone Marrow Transplant Unit at Hammersmith Hospital ICHNHST.

Relapse is a major cause of treatment failure in haploidentical haematopoietic progenitor cell transplant (HPCT) with PTCy. Natural killer cells suppress graft versus host disease and mediate the graft versus leukaemia effect, driven by killer cell immunoglobulin-like receptors (KIRs). Emerging research suggests that donor KIR genotype may influence graft outcome in haploidentical transplants with varying impacts between patient cohorts. This study investigates whether donors with greater KIR B motifs associate with outcomes such as greater relapse-free survival (RFS), overall survival (OS), nonrelapse mortality (NRM), acute graft versus host disease (GvHD) and infection. The study cohort included 98 haploidentical donor-recipient (D/R) pairs (myeloablative n = 37, RIC n = 61) with various haematological malignancies, receiving primary T-cell replete haploidentical HSCT with PTCγ. Following KIR SSO genotyping, donors are categorised into neutral (n = 63) or better and best (n = 35), based on KIR B motif content. Kaplan-Meier and Cox regression survival functions are performed to investigate associations with outcomes. Our results show that the better and best category has significantly poorer RFS (p = 0.013; hazard ratio [HR] 3.16, 95% CI 1.21-8.24: p = 0.018). The greater risk of relapse associated with poorer OS (p = 0.011; HR 2.24, 95% CI 1.18-4.24: p = 0.01) in the better and best category. The competing KIR receptor-ligand and missing licensing proof models failed to predict transplant outcomes. Here, we show neutral donors associate with favourable outcomes in T-cell replete haplo-HPCT with PTCγ after categorisation using the KIR B content model, due to the increased risk of relapse associated with the use of better and best donors.

Sclerotic-Type Cutaneous Chronic Graft-Versus-Host Disease Exhibits Activation of T Helper 1 and OX40 Cytokines.

Sclerotic-type cutaneous chronic graft-versus-host disease is a severe complication of allogeneic hematopoietic stem cell transplantation, with profound morbidity. A dearth of effective, targeted treatment options necessitates further investigation into the molecular mechanisms underlying this T-cell-mediated disease. In this study, we compared the transcriptome in skin biopsies from pediatric and young adult (aged <25 years) patients with sclerotic-type cutaneous chronic graft-versus-host disease (n = 7) with that in demographically matched healthy controls (n = 8) and patients with atopic dermatitis (n = 10) using RNA sequencing with RT-PCR and immunohistochemistry validation. Differential expression was defined as fold change > 1.5 and false discovery rate < 0.05. Sclerotic-type cutaneous chronic graft-versus-host disease exhibited strong and significant T helper (Th)1 skewing through key related cytokines and chemokines (CXCL9/10/11, IFNG/IFN-γ, STAT1/signal transducer and activator of transcription 1). Several markers related to the TSLP-OX40 axis were significantly upregulated relative to those in both controls and lesional atopic dermatitis, including TNFSF4/OX40L, TSLP, and IL33, as well as fibroinflammatory signatures characterized in a prior study in systemic sclerosis. Gene set variation analysis reflected marker-level findings, showing the greatest enrichment of the Th1 and fibroinflammatory pathways, with no global activation identified in Th2 or Th17/Th22. Cell-type deconvolution revealed a significant representation of macrophages and vascular endothelial cells. Sclerotic-type cutaneous chronic graft-versus-host disease in young patients may therefore be characterized by strong Th1-related upregulation with a unique TSLP-OX40 signature, suggesting new therapeutic avenues for this devastating disease.

Donor aKIR genes influence the risk of EBV and CMV reactivation after anti-thymocyte globulin-based haploidentical hematopoietic stem cell transplantation.

Hematopoietic stem cell transplantation (HSCT) offers the highest curative potential for patients with hematological malignancies. Complications including infection, graft-versus-host disease (GVHD), and relapse reflect delayed or dysregulated immune reconstitution. After transplantation, NK cells rapidly reconstitute and are crucial for immune surveillance and immune tolerance. NK cell function is tightly regulated by killer immunoglobin-like receptors (KIRs). Previous studies have revealed that donor KIRs, especially some activated KIRs (aKIRs) are closely related to transplant outcomes. Here, we performed a retrospective study, including 323 patients who received haploidentical (haplo) HSCT in our center. In univariate analysis, donor KIR2DS1, KIR2DS3 and KIR3DS1 gene protected patients with lymphoid disease from Epstein-Barr virus (EBV) and cytomegalovirus (CMV) reactivation, while donor KIR2DS1, KIR2DS5 and KIR3DS1 gene conferred a higher risk of CMV reactivation for patients with myeloid disease. Multivariate analysis confirmed that donor telomeric (Tel) B/x and KIR2DS3 gene best protected patients with lymphoid disease from EBV (p = 0.017) and CMV reactivation (p = 0.004). In myeloid disease, grafts lacking Tel B/x and KIR2DS5 gene correlated with the lowest risk of CMV reactivation (p = 0.018). Besides, donor aKIR genes did not influence the rates of GVHD, relapse, non-relapse mortality (NRM) and overall survival (OS) in this study. The reactivation of EBV and CMV was associated with poor prognosis of haplo-HSCT. In conclusion, we found that donor aKIR genes might have a synergistic effect on CMV and EBV reactivation after haplo-HSCT. Whether the influence of donor aKIR genes varies with disease types remained to be studied.

Longitudinal dynamics of gut microbiota in the pathogenesis of acute graft-versus-host disease.

AIM: The gut microbiota has been reported to be associated with acute graft-versus-host disease (aGvHD) in hematopoietic stem cell transplantation (HSCT). Dynamic surveillance of the microbiota is required to understand the detailed pathogenesis involved in the process of aGvHD. METHODS: Fecal samples were collected prospectively at four timepoints, including pre-HSCT (T1), graft infusion (T2), neutrophil engraftment (T3), and 30 days after transplantation (T4). Fecal samples were profiled by 16S ribosomal RNA gene sequencing to assess the microbiota composition. RESULTS: From the T1 to T4 timepoint, the diversity of the gut microbiota decreased, and the dominant species also changed, with a decrease in the obligate anaerobic bacteria and a shift toward a "pathogenic community". Compared with non-aGvHD patients, aGvHD patients had a lower abundance of Roseburia at T1 and a higher abundance of Acinetobacter johnsonii at T2. Furthermore, Acinetobacter johnsonii was negatively correlated with the secretion of IL-4 and TNF-α. At T3, Rothia mucilaginos was demonstrated to be linked with a decreased risk of aGvHD, which was accompanied by decreased secretion of IL-8. At T4, higher abundances of Lactobacillus paracasei and Acinetobacter johnsonii were identified to be related with aGvHD. Lactobacillus paracasei was associated with the downregulation of IL-10, and Acinetobacter johnsonii was associated with the downregulation of IL-2 and TNF-α. CONCLUSIONS: Dynamic changes in gut microbiota composition and related cytokines were found to be related to aGvHD, including pathogenic or protective changes. These findings suggested that manipulation of gut microbiota at different timepoints might be a promising avenue for preventing or treating this common complication.

Significance of HLA-E and its two NKG2 receptors in development of complications after allogeneic transplantation of hematopoietic stem cells.

Transplantation of hematopoietic stem cells (HSCT) is a procedure commonly used in treatment of various haematological disorders which is associated with significantly improved survival rates. However, one of its drawbacks is the possibility of development of post-transplant complications, including acute and chronic graft-versus-host disease (GvHD) or CMV infection. Various studies suggested that NK cells and their receptors may affect the transplant outcome. In the present study, patients and donors were found to significantly differ in the distribution of the NKG2A rs7301582 genetic variants - recipients carried the C allele more often than their donors (0.975 vs 0.865, p<0.0001). Increased soluble HLA-E (sHLA-E) levels detected in recipients' serum 30 days after transplantation seemed to play a prognostic and protective role. It was observed that recipients with higher sHLA-E levels were less prone to chronic GvHD (11.65 vs 6.33 pg/mL, p=0.033) or more severe acute GvHD grades II-IV (11.07 vs 8.04 pg/mL, p=0.081). Our results also showed an unfavourable role of HLA-E donor-recipient genetic incompatibility in CMV infection development after transplantation (OR=5.92, p=0.014). Frequencies of NK cells (both CD56dim and CD56bright) expressing NKG2C were elevated in recipients who developed CMV, especially 30 and 90 days post-transplantation (p<0.03). Percentages of NKG2C+ NK cells lacking NKG2A expression were also increased in these patients. Moreover, recipients carrying a NKG2C deletion characterized with decreased frequency of NKG2C+ NK cells (p<0.05). Our study confirms the importance of NK cells in the development of post-transplant complications and highlights the effect of HLA-E and NKG2C genetic variants, sHLA-E serum concentration, as well as NKG2C surface expression on transplant outcome.

CRISPR/Cas-based gene editing in therapeutic strategies for beta-thalassemia.

Beta-thalassemia (ß-thalassemia) is an autosomal recessive disorder caused by point mutations, insertions, and deletions in the HBB gene cluster, resulting in the underproduction of ß-globin chains. The most severe type may demonstrate complications including massive hepatosplenomegaly, bone deformities, and severe growth retardation in children. Treatments for ß-thalassemia include blood transfusion, splenectomy, and allogeneic hematopoietic stem cell transplantation (HSCT). However, long-term blood transfusions require regular iron removal therapy. For allogeneic HSCT, human lymphocyte antigen (HLA)-matched donors are rarely available, and acute graft-versus-host disease (GVHD) may occur after the transplantation. Thus, these conventional treatments are facing significant challenges. In recent years, with the advent and advancement of CRISPR (clustered regularly interspaced short palindromic repeats)/Cas9 (CRISPR-associated protein 9) gene editing technology, precise genome editing has achieved encouraging successes in basic and clinical studies for treating various genetic disorders, including ß-thalassemia. Target gene-edited autogeneic HSCT helps patients avoid graft rejection and GVHD, making it a promising curative therapy for transfusion-dependent ß-thalassemia (TDT). In this review, we introduce the development and mechanisms of CRISPR/Cas9. Recent advances on feasible strategies of CRISPR/Cas9 targeting three globin genes (HBB, HBG, and HBA) and targeting cell selections for ß-thalassemia therapy are highlighted. Current CRISPR-based clinical trials in the treatment of ß-thalassemia are summarized, which are focused on γ-globin reactivation and fetal hemoglobin reproduction in hematopoietic stem cells. Lastly, the applications of other promising CRISPR-based technologies, such as base editing and prime editing, in treating ß-thalassemia and the limitations of the CRISPR/Cas system in therapeutic applications are discussed.

Targeting PRMT1 prevents acute and chronic graft-versus-host disease.

Graft-versus-host disease (GVHD) is a common complication after allogeneic hematopoietic stem cell transplantation. Recent studies have reported that protein arginine methyltransferase 1 (PRMT1) is essential for the differentiation and proliferation of T and B cells. Therefore, it is possible that PRMT1 may play a critical role in GVHD. In this study, we observed that PRMT1 expression was upregulated in CD4+ T and B cells from chronic GVHD (cGVHD) patients and mice. However, the prophylactic use of a PRMT1 inhibitor significantly prevented cGVHD in mice by reducing the percentage of T helper (Th)17 cells, germinal center B cells, and plasma cells. The PRMT1 inhibitor also controlled acute GVHD (aGVHD) in mice by decreasing the percentage of Th17 cells. Moreover, inhibiting PRMT1 also weakened Th17 cell differentiation, B cell proliferation, and antibody production in cells from cGVHD patients. Additionally, further studies revealed that PRMT1 regulated B cell proliferation and antibody secretion by methylating isocitrate dehydrogenase 2 (IDH2). We observed asymmetric di-methylation of IDH2 by PRMT1 at arginine 353 promoted IDH2 homodimerization, which enhanced IDH2 activity, further increasing B cell proliferation and antibody production. Collectively, this study provides a rationale for the application of PRMT1 inhibitors in the prevention of aGVHD and cGVHD.

The influence of methotrexate-related transporter and metabolizing enzyme gene polymorphisms on peri-engraftment syndrome and graft-versus-host disease after haplo-hematopoietic stem cell transplantation in pediatric patients with malignant hematological diseases.

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

Spatial transcriptomics reveals distinct tissue niches linked with steroid responsiveness in acute gastrointestinal GVHD.

Severe acute graft-versus-host disease (aGVHD) is associated with significant mortality and morbidity, especially in steroid-resistant (SR) cases. Spatial transcriptomic technology can elucidate tissue-based interactions in vivo and possibly identify predictors of treatment response. Tissue sections from 32 treatment-naïve patients with biopsy-confirmed lower gastrointestinal (GI) aGVHD were obtained. The GeoMx digital spatial profiler was used to capture transcriptome profiles of >18 000 genes from different foci of immune infiltrates, colonic epithelium, and vascular endothelium. Each tissue compartment sampled showed 2 distinct clusters that were analyzed for differential expression and spatially resolved correlation of gene signatures. Classic cell-mediated immunity signatures, normal differentiated epithelial cells, and inflamed vasculature dominated foci sampled from steroid-sensitive cases. In contrast, a neutrophil predominant noncanonical inflammation with regenerative epithelial cells and some indication of angiogenic endothelial response was overrepresented in areas from SR cases. Evaluation of potential prognostic biomarkers identified ubiquitin specific peptidase 17-like (USP17L) family of genes as being differentially expressed in immune cells from patients with worsened survival. In summary, we demonstrate distinct tissue niches with unique gene expression signatures within lower GI tissue from patients with aGVHD and provide evidence of a potential prognostic biomarker.

The Role of MicroRNA in Graft-Versus-Host-Disease: A Review.

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

Discrepancy between recipient and donor rs4364254 heparanase single nucleotide polymorphism impacts graft-versus-host disease after allogeneic stem cell transplant.

INTRODUCTION: The heparanase (HPSE) gene is highly polymorphic, but only a minority of its single nucleotide polymorphisms (SNPs) have been studied. Among these, rs4693608 and rs4364254 SNPs are closely associated with mRNA expression and HPSE protein levels in healthy subjects. Given the association between HPSE and inflammatory response, we aimed to evaluate whether HPSE rs4693608 and rs4364254 SNPs could have an impact on graft-versus-host disease after allogeneic stem cell transplants (HSCT). METHODS: A total of 228 consecutive patients who underwent HSCT at our center between 2005 and 2018 were included. The rs4693608 SNP was identified by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis, while the rs4364254 was detected by allele-specific amplification. RESULTS: The recipient-donor discrepancy for rs4364254 HPSE SNP was significantly associated with grade II-IV aGvHD (HR 1.75, p = 0.03). Patients were stratified into risk groups as follows: low-risk group (LDR) including TT-TT, TT-CT, CT-TT, CC-CC; high-risk group (HDR) including CC-CT, CC-TT, CT-CC, CT-CT, TT-CC. Day 100 cumulative incidence of grade II-IV aGvHD was 23.4% in the LDR group and 41.4% in the HDR group (p = 0.01). One-year cumulative incidence of moderate/severe cGvHD was 42.6% in the LDR group and 58.6% in the HDR group (p = 0.04). Independent variables for moderate/severe cGvHD in patients who received myeloablative conditioning included donor rs4693608 SNP (GA/AA vs. GG: HR 6.86, p = 0.008), rs4693608-rs4364254 SNP combination in recipient (HR/MR vs. LR: HR 3.67, p = 0.01), and previous grade II-IV aGvHD (HR 3.28, p = 0.0005). Finally, donors with rs4364254 SNP CC conferred increased transplant-related mortality (TRM) (39.1% vs. 25%, p = 0.03) and decreased graft-relapse free survival (GRFS) (23.5% vs. 34.4%, p = 0.04) compared with CT or TT genotypes. CONCLUSION: The differences in incidence of GvHD according to recipient-donor genotype combinations suggests a possible role for rs4364254 HPSE SNP in predicting GvHD. A high level of HPSE, particularly linked to CC genotype of rs4364254 SNP may promote alloreactive T lymphocytes activation and migration toward target organs.