Human leukocyte antigen evolutionary divergence as a novel risk factor for donor selection in acute lymphoblastic leukemia patients undergoing haploidentical hematopoietic stem cell transplantation.

Introduction: The human leukocyte antigen (HLA) evolutionary divergence (HED) reflects immunopeptidome diversity and has been shown to predict the response of tumors to immunotherapy. Its impact on allogeneic hematopoietic stem cell transplantation (HSCT) is controversial in different studies. Methods: In this study, we retrospectively analyzed the clinical impact of class I and II HED in 225 acute lymphoblastic leukemia patients undergoing HSCT from related haploidentical donors. The HED for recipient, donor, and donor-recipient pair was calculated based on Grantham distance, which accounts for variations in the composition, polarity, and volume of each amino acid within the peptide-binding groove of two HLA alleles. The median value of HED scores was used as a cut-off to stratify patients with high or low HED. Results: The class I HED for recipient (R_HEDclass I) showed the strongest association with cumulative incidence of relapse (12.2 vs. 25.0%, P = 0.00814) but not with acute graft-versus-host disease. The patients with high class II HED for donor-recipient (D/R_HEDclass II) showed a significantly higher cumulative incidence of severe aGVHD than those with low D/R_HEDclass II (24.0% vs. 6.1%, P = 0.0027). Multivariate analysis indicated that a high D/R_HEDclass II was an independent risk factor for the development of severe aGVHD (P = 0.007), and a high R_HEDclass I had a more than two-fold reduced risk of relapse (P = 0.028). However, there was no discernible difference in overall survival (OS) or disease-free survival (DFS) for patients with high or low HED, which was inconsistent with the previous investigation. Discussion: While the observation are limited by the presented single center retrospective cohort, the results show that HED has poor prognostic value in OS or DFS, as well as the associations with relapse and aGVHD. In haploidentical setting, class II HED for donor-recipient pair (D/R_HEDclass II) is an independent and novel risk factor for finding the best haploidentical donor, which could potentially influence clinical practice if verified in larger cohorts.

Identification of predictive models including polymorphisms in cytokines genes and clinical variables associated with post-transplant complications after identical HLA-allogeneic stem cell transplantation.

Backgrounds: Although allogeneic hematopoietic stem cell transplantation (allo-HSCT) is a potentially curative therapy for hematological malignancies, it can be associated with relevant post-transplant complications. Several reports have shown that polymorphisms in immune system genes are correlated with the development of post-transplant complications. Within this context, this work focuses on identifying novel polymorphisms in cytokine genes and developing predictive models to anticipate the risk of developing graft-versus-host disease (GVHD), transplantation-related mortality (TRM), relapse and overall survival (OS). Methods: Our group developed a 132-cytokine gene panel which was tested in 90 patients who underwent an HLA-identical sibling-donor allo-HSCT. Bayesian logistic regression (BLR) models were used to select the most relevant variables. Based on the cut-off points selected for each model, patients were classified as being at high or low-risk for each of the post-transplant complications (aGVHD II-IV, aGVHD III-IV, cGVHD, mod-sev cGVHD, TRM, relapse and OS). Results: A total of 737 polymorphisms were selected from the custom panel genes. Of these, 41 polymorphisms were included in the predictive models in 30 cytokine genes were selected (17 interleukins and 13 chemokines). Of these polymorphisms, 5 (12.2%) were located in coding regions, and 36 (87.8%) in non-coding regions. All models had a statistical significance of p<0.0001. Conclusion: Overall, genomic polymorphisms in cytokine genes make it possible to anticipate the development all complications studied following allo-HSCT and, consequently, to optimize the clinical management of patients.

Effect of CYP3A5 Gene Polymorphisms on Tacrolimus Blood Concentrations and Adverse Events in Allogeneic Hematopoietic Stem Cell Transplant Patients.

BACKGROUND: Tacrolimus is the core basic immunosuppressant after transplantation. Cytochrome P450 3A5 (CYP3A5) is the main enzyme involved in tacrolimus metabolism, and rs776746A>G is the most frequently studied polymorphism in the CYP3A5 gene. The aim of this study was to investigate the effect of CYP3A5 gene polymorphisms on tacrolimus blood concentrations and acute graft versus host disease (GVHD) in patients with allogeneic hematopoietic stem cell transplantation (allo-HSCT). METHODS: This study included adult patients who received allo-HSCT at the First Affiliated Hospital of Wannan Medical College from January 2021 to June 2022, and received postoperative treatment with tacrolimus. Tacrolimus blood levels were obtained by fully automatic chemiluminescence immunoassay analyzer. Polymerase chain reaction/restriction fragment length polymorphism was used to genotype for CYP3A5*3 allelic variants. RESULTS: In a total of 50 transplant patients, 30 patients were detected with CYP3A5*3/*3 genotype, 15 patients with CYP3A5*1/*3 genotype, and 5 patients with CYP3A5*1/*1 genotype. The initial tacrolimus blood concentrations in allo-HSCT patients with CYP3A5*1/*1, *1/*3, and *3/*3 genes were 7.75, 8.61, and 10.19 ng/mL, respectively; The initial blood concentration/dose (C/D) ratios were 4.08, 4.42 and 5.66 ng/(mL·mg), respectively. The C/D ratios of allo-HSCT patients carrying CYP3A5*1/*1, *1/*3, and *3/*3 genes were 4.35 and 4.71 and 5.58, 4.19, 4.56 and 5.71 ng/(mL·mg) in the second and 3rd weeks after operation. These results showed that the blood concentration and C/D ratio of tacrolimus in patients with CYP3A5*3/*3 genotype were significantly higher than those in patients with CYP3A5*1/*3 or CYP3A5*1/*1 genotype. Moreover, the incidence of acute GVHD after allo-HSCT in patients with CYP3A5*1/*1 genotype was significantly higher than that in patients with CYP3A5*1/*3 or CYP3A5*3/*3 genotype. CONCLUSIONS: Most patients carry the mutant allele CYP3A5*3. CYP3A5 gene polymorphisms affect tacrolimus blood concentrations and acute GVHD after allo-HSCT.

Impact of spliceosome mutation on outcomes of myelodysplastic syndrome and chronic myelomonocytic leukemia patients undergoing allogeneic hematopoietic cell transplantation.

INTRODUCTION: Allogeneic Hematopoietic cell transplantation (allo-HCT) remains the only curative therapy for myelodysplastic syndrome (MDS) and chronic myelomonocytic leukemia (CMML). The impact of spliceosome mutations on allo-HCT outcome is unclear and further understanding is needed to assess the implications of this class of mutations on risk of relapse, overall survival (OS) and non-relapse mortality (NRM) in order to make decision regarding timing of allo-HCT. We examined the allo-HCT outcomes of MDS/CMML patients based on their spliceosome mutation profile to understand the impact of these mutations on transplant outcomes. OBJECTIVE: To compare outcomes of MDS/CMML patients with and without spliceosome mutations undergoing allo-HCT. METHODS: This is a single institution, retrospective study of MDS/CMML patients who underwent allo-HCT with myeloablative or reduced intensity conditioning (RIC) regimen at City of Hope from January 2016 to December 2021. Among them, patients who underwent molecular mutation profiling by NGS (Next Generation Sequencing) for a set of genes known to be mutated in myeloid neoplasms are included in this analysis. We compared OS, relapse free survival, NRM and acute/chronic graft versus host disease (GVHD) incidence between the spliceosome-mutated and unmutated groups. RESULTS: We identified 258 consecutive MDS/CMML patients who underwent allo-HCT. Of these, 126 (48.8 %) patients had molecular profiling done among whom 57 (45.2 %) patients carried a spliceosome mutation. 84.9 % of patients had MDS and 55.6 % underwent a matched unrelated donor transplant. The median age for the whole cohort was 66 years (range 12-77).78.6 % and 73.7 % received RIC in the spliceosome and non-spliceosome groups, respectively. The 2-year OS for the whole cohort was 66.5 % (95 %CI 0.55-0.75) with a day 100 NRM of 7.1 % and 2-year cumulative incidence of relapse of 20 %. Grade II-IV acute GVHD at day 100 was 36.3 % (95 % CI 0.27-0.44) and any chronic GVHD at 2-years was 48.4 % (95 % CI 0.37-0.58). Patients who carried a spliceosome mutation had a significantly better 2-year survival of 83.8 % vs 55.9 % in the non-spliceosome group (P=0.002) and a better PFS of 73.7 % vs 50.0 % (P=0.007). There was no difference in the cumulative incidence of relapse at 2-years 15.9 % vs 18.5 % (P=0.59) between two groups but the spliceosome group had a significantly lower NRM at 2-years 10.4 % vs 31.5 % (P=0.009). There was no difference in incidence of acute or chronic GVHD between the two groups. CONCLUSIONS: Among patients with MDS or CMML who underwent allo-HCT, our study shows better OS for patients who have spliceosome mutations due to lower NRM compared to those carrying non- spliceosome mutations. This favorable outcome of the spliceosome-mutated patients could have implications for timing of allo-HCT, particularly for patients in the intermediate MDS prognostic risk groups.

Is HLA-E with its receptors an immune checkpoint or an antigenic determinant in allo-HCT?

Hematopoietic cell transplantation (HCT) represents a potentially curative therapeutic approach for various hematologic and non-hematologic malignancies. Human leukocyte antigen (HLA) matching is still the central selection criterion for HCT donors. Nevertheless, post-transplant complications, in particular graft-versus-host disease (GvHD), relapse of disease and infectious complications, represent a major challenge and contribute significantly to morbidity and mortality. Recently, non-classical HLA class I molecules, especially HLA-E, have gained increasing attention in the context of allogeneic HCT. This review aims to summarize the latest findings on the immunomodulatory role of HLA-E, which serves as a ligand for receptors of the innate and adaptive immune system. In particular, we aim to elucidate how (i) polymorphisms within HLA-E, (ii) the NKG2A/C axis and (iii) the repertoire of peptides presented by HLA-E jointly influence the functionality of immune effector cells. Understanding this intricate network of interactions is crucial as it significantly affects NK and T cell responses and thus clinical outcomes after HCT.

Recipient IL-17A polymorphism rs2275913 is associated with acute graft-versus-host disease after single-unit cord blood transplantation.

BACKGROUND: Interleukin-17 (IL-17) is elevated in human inflammatory and autoimmune diseases. The polymorphism in the promoter region of the IL-17 A gene is associated with susceptibility to several inflammatory diseases, including acute graft-versus-host disease (GVHD) following allogeneic hematopoietic cell transplantation from adult donors. However, the impacts of IL-17 A polymorphism on cord blood transplantation (CBT) outcomes remain unclear. OBJECTIVE: The objective of this study was to assess the impact of IL-17 A polymorphism rs2275913 on GVHD, survival, relapse, non-relapse mortality (NRM), and hematopoietic recovery after CBT. STUDY DESIGN: We conducted a retrospective analysis of data from adult patients who underwent single-unit CBT at our institution from January 2005 to March 2023 for whose recipient or donor DNA samples were available. IL-17 A genotyping was performed using real-time polymerase chain reaction with the TaqMan® SNP genotyping assay for rs2275913. RESULTS: A total of 158 recipients and 136 donors were evaluated in this study. Multivariate analysis showed that rs2275913 GA or AA recipients were associated with increased risk of grades II to IV acute GVHD compared to GG recipients (hazard ratio [HR], 1.46; 95% confidence interval [CI], 1.00-2.13; P = 0.047). Serum IL-17 A levels at eight weeks were significantly higher in rs2275913 GA or AA recipients compared to GG. The rs2275913 polymorphism did not affect survival, relapse, NRM, or hematopoietic recovery after single-unit CBT. CONCLUSION: Our data showed recipient IL-17 A polymorphism rs2275913 was associated with the risk of grade II to IV acute GVHD in adults undergoing single-unit CBT. However, the rs2275913 polymorphism in recipients and donors did not affect survival or relapse. Thus, the polymorphism of IL-17 A rs2275913 in recipients might predict the risk of acute GVHD after single-unit CBT.

The CD28 IVS3 + 17 T/C polymorphism and the GVHD occurrence in Tunisian patients receiving an HLA-identical sibling HSCs transplant.

Graft-versus-host disease (GVHD) is a potentially serious complication ofallogeneic hematopoietic stem cell transplantation (HSCT). Graft-contaminating T cells (donor T cells) arecrucial for the development ofGVHD since they are able to react against the recipient's antigens. In this study we aim toevaluatethepotentialassociation between the IVS3 + 17 T/C gene variation in the CD28 molecule, a T cells costimulatory factor, and the GVHD occurrence in a Tunisian group of recipients of allo-HSCTs. Results show that there is an association between the presence of this polymorphism and the occurrence of grades II-IV acute GVHD (OR: 2.470, I.C: 1.027-5.938, p = 0.043). As for the chronic GVHD, it seems that the studied gene variation has no impact on the occurrence of this complication, which appeared likely to be affected by the HSCT graft source (PBSC: peripheral blood stem cells) (OR: 5.141, I.C: 1.590-16.620, p = 0.006). Based on these data, we believe that the CD28 IVS3 + 17 T/C polymorphism is a significant factor in the pathogenesis of acute GVHD.

Clonal Hematopoiesis-Associated Gene Mutations Affect Acute Graft-Versus-Host Disease After Hematopoietic Stem Cell Transplantation in AML Patients.

BACKGROUND The relationship between clonal hematopoiesis (CH)-associated gene mutations and allogeneic hematopoietic stem cell transplantation (allo-HSCT) has been extensively studied since next-generation sequencing (NGS) technology became widely available. However, research has mainly focused on the relationship between donor CH mutations and transplant prognosis, and research into the relationship between CH mutations in the recipient and acute graft-versus-host disease (aGVHD) is lacking. MATERIAL AND METHODS We analyzed NGS results and their correlation with aGVHD and prognosis in 196 AML patients undergoing allo-HSCT. RESULTS A total of 93 (47.4%) patients had CH mutations. The most frequently mutated genes were DNMT3A (28 of 196; 14.3%), TET2 (22 of 196; 11.2%), IDH1 (15 of 196; 7.7%), IDH2 (14 of 196; 7.1%), and ASXL1 (13 of 196; 6.6%). The incidence of aGVHD was higher in patients older than 45 years old with DTA mutations (DNMT3A, TET2 or ASXL1). DNMT3A mutation but not with TET2 or ASXL1 mutation was an independent risk factor for aGVHD in patients receiving allo-HSCT older than 45 years old. With a median follow-up of 42.7 months, CH mutations were not associated with overall survival and leukemia-free survival. CONCLUSIONS DNMT3A mutation, but not TET2 or ASXL1 mutation, was associated with higher incidence of aGVHD.

Unravelling the potential of TIM-3 gene polymorphism in allogeneic hematopoietic stem cell transplantation - a preliminary study.

BACKGROUND: T-cell immunoglobulin and mucin-domain containing-3 (TIM-3) molecule is a key regulator of the immune response by exerting an inhibitory effect on various types of immune cells. Understanding the role of TIM-3 in hematopoietic stem cell transplantation (HSCT) may improve transplant outcomes. Our study evaluated the potential association between TIM-3 polymorphisms, namely rs1036199 (A > C) or rs10515746 (C > A), changes which are located in exon 3 and the promoter region of the TIM-3 gene, and post-HSCT outcomes. METHODS: One-hundred and twenty allogeneic HSCT patients and their respective donors were enrolled and genotyped for TIM-3 single nucleotide polymorphisms (SNPs) using real-time PCR with TaqMan assays. RESULTS: We found that the presence of the rare alleles and heterozygous genotypes of studied SNP in recipients tended to protect against or increase the risk for acute graft-versus-host disease (aGvHD). For the rs1036199 polymorphism, recipients with the AC heterozygous genotype (p = 0.0287) or carrying the rarer C allele (p = 0.0334) showed a lower frequency of aGvHD development along all I-IV grades. A similar association was detected for the rs10515746 polymorphism as recipients with the CA genotype (p = 0.0095) or the recessive A allele (p = 0.0117) less frequently developed aGvHD. Furthermore, the rarer A allele of rs10515746 SNP was also associated with a prolonged aGvHD-free survival (p = 0.0424). Cytomegalovirus (CMV) infection was more common in patients transplanted with TIM-3 rs10515746 mismatched donors (p = 0.0229) and this association was also found to be independent of HLA incompatibility and pre-transplant CMV-IgG status. Multivariate analyses confirmed the role of these recessive alleles and donor-recipient TIM-3 incompatibility as an independent factor in aGvHD and CMV development. CONCLUSIONS: Polymorphism of TIM-3 molecule may affect the immune response in HSCT patients. The recessive alleles of rs1036199 and rs10515746 SNPs decreased the risk of developing aGvHD. TIM-3 donor-recipient genetic matching may also affect the risk of post-transplant CMV infection, indicating the potential value of genetic profiling in optimizing transplant strategies.

Application of CD25 and CTLA4 gene transcription levels in early prediction of acute graft-versus-host disease.

Introduction: Our study investigated the potential of peripheral blood T cell CD25, CD28, and CTLA-4 gene transcription levels as predictive biomarkers for acute graft-versus-host disease (aGVHD) following allogeneic hematopoietic stem cell transplantation (allo-HSCT). Methods: Real-time reverse transcription fluorescent quantitative PCR (RT-qPCR) analysis was conducted on day +7, +14, and +21 post-transplantation in patients undergoing allo-HSCT. Results: Elevated levels of CD25 and CTLA-4 mRNA were found to be associated with the occurrence of aGVHD, as well as severe and gastrointestinal aGVHD. Receiver operating characteristic (ROC) curve analysis was utilized to assess the predictive value of each biomarker. Combined analysis of CD25 and CTLA-4 mRNA levels demonstrated promising predictive potential for aGVHD. Conclusion: Our results confirmed that the transcription levels of CD25 and CTLA-4 genes could be used as early predictive biomarkers for aGVHD post-allo-HSCT.

The impact of MICB mismatches in unrelated haematopoietic stem cell transplantation.

MICA polymorphisms have been associated with increased incidence of acute GvHD and adverse outcome in allogeneic haematopoietic stem cell transplantation (HSCT). MICB is another expressed member of MHC class I-related chain genes and its impact on HSCT outcome is yet to be fully defined. We typed a large cohort of patients and donors for MICB polymorphisms and investigated the impact of MICB matching on outcome after unrelated HSCT. 69.2% of the patients were 10/10 human leukocyte antigen (HLA) matched and 30.8% were 9/10 HLA matched. MICB typing was performed using a short amplicon-based NGS typing assay on the Illumina MiSeq platform. Differences in proteins were considered as mismatches. MICA polymorphisms were identified as possible confounder and were therefore included as parameter in the multivariate analyses. Due to the strong linkage disequilibrium with the classical HLA-genes, sub-stratification for HLA matching status was necessary, and no effect of MICB mismatches was seen in the 10/10 HLA matched group when compared to the MICB matched cases. However, in the 9/10 HLA matched group, MICB mismatched cases showed significantly worse disease free survival (DFS), GvHD and relapse free survival (GRFS) compared to the MICB matched cases (DFS: HR 1.24, p = 0.011; GRFS: HR 1.26, p = 0.002). MICA mismatches had no impact on any outcome parameter. According to our findings, effects previously attributed to MICA differences may have been confounded by MICB polymorphisms. We show that MICB differences contribute a small but relevant effect in 9/10 HLA-matched transplantations, which in turn highlights the possible usefulness of MICB typing in donor selection among similarly suitable 9/10 matched donors, especially when HLA-B mismatches have to be accepted.

MICB Genetic Variants and Its Protein Soluble Level Are Associated with the Risk of Chronic GvHD and CMV Infection after Allogeneic HSCT.

The aim of the present study was to determine the associations between the MICB genetic variability and the expression and the risk of development of post-transplant complications after allogeneic hematopoietic stem cell transplantation (HSCT). HSCT recipients and their donors were genotyped for two MICB polymorphisms (rs1065075, rs3828903). Moreover, the expression of a soluble form of MICB was determined in the recipients' serum samples after transplantation using the Luminex assay. Our results revealed a favorable role of the MICB rs1065075 G allele. Recipients with donors carrying this genetic variant were less prone to developing chronic graft-versus-host disease (cGvHD) when compared to recipients without any symptoms of this disease (41.41% vs. 65.38%, p = 0.046). Moreover, the MICB rs1065075 G allele was associated with a lower incidence of cytomegalovirus (CMV) reactivation, both as a donor (p = 0.015) and as a recipient allele (p = 0.039). The MICB rs1065075 G variant was also found to be associated with decreased serum soluble MICB (sMICB) levels, whereas serum sMICB levels were significantly higher in recipients diagnosed with CMV infection (p = 0.0386) and cGvHD (p = 0.0008) compared to recipients without those complications. A protective role of the G allele was also observed for the rs3828903 polymorphism, as it was more frequently detected among donors of recipients without cGvHD (89.90% vs. 69.23%; p = 0.013). MICB genetic variants, as well as serum levels of sMICB, may serve as prognostic factors for the risk of developing cGvHD and CMV infection after allogeneic HSCT.

HLA-DPB1 and DPA1 ~ DPB1 linkage mismatch affects the survival of recipients receiving HLA-14/14 matched unrelated donor HSCT.

To analyse the effect of HLA-DPA1 and HLA-DPB1 allelic mismatches on the outcomes of unrelated donor haematopoietic stem cell transplantation (URD-HSCT), we collected 258 recipients with haematological disease who underwent HLA-10/10 matched URD-HSCT. HLA-A, -B, -C, -DRB1, -DQB1, -DRB3/4/5, -DQA1, -DPA1 and -DPB1 typing was performed for the donors and recipients using next-generation sequencing (NGS) technology. After excluding 8 cases with DQA1 or DRB3/4/5 mismatches, we included 250 cases with HLA-14/14 matching for further analysis. Our results showed that the proportion of matched DPA1 and DPB1 alleles was only 10.4% (26/250). The remaining 89.6% of donors and recipients demonstrated DPA1 or DPB1 mismatch. In the DPA1 matched and DPB1 mismatched group, accounting for 18.8% (47/250) of the cohort, DPB1*02:01/DPB1*03:01 allelic mismatches were associated with decreased 2-year OS and increased NRM. DPB1*02:02/DPB1*05:01 and DPB1*02:01/DPB1*05:01 mismatches showed no impact on outcomes. Moreover, the specific allelic mismatches observed were consistent with the DPB1 T-cell epitope (TCE) classification as permissive and non-permissive. We innovatively established an analysis method for DPA1 ~ DPB1 linkage mismatch for cases with both DPA1 and DPB1 mismatched, accounting for 70% (175/250) of the total. DPA1*02:02 ~ DPB1*05:01/DPA1*02:01 ~ DPB1*17:01 linkage mismatches were associated with lower 2-year OS, especially among AML/MDS recipients. DPA1*02:02 ~ DPB1*05:01/DPA1*01:03 ~ DPB1*02:01 linkage mismatches showed no impact on outcomes. In conclusion, applying the DPA1 ~ DPB1 linkage mismatch analysis approach can identify different types of mismatches affecting transplant outcomes and provide valuable insight for selecting optimal donors for AML/MDS and ALL recipients.

Effect of IL-2 polymorphism rs2069762 on single-unit cord blood transplant outcomes.

BACKGROUND: Interleukin-2 (IL-2) is one of the most important cytokines that regulate the activation and proliferation of T cells and natural killer cells. The production of IL-2 may be affected by polymorphisms in the promoter region of the IL-2 gene (rs2069762). In allogeneic hematopoietic cell transplantation (HCT) from adult donors, rs2069762 has been associated with the incidence of acute and chronic graft-versus-host disease (GVHD). However, the impacts of IL-2 polymorphism on cord blood transplantation (CBT) outcomes remain unclear. OBJECTIVE: The objective of this study was to assess the impact of IL-2 polymorphism rs2069762 on transplant outcomes, such as hematopoietic recovery, GVHD, overall survival, relapse, and non-relapse mortality (NRM) after CBT. STUDY DESIGN: We conducted a retrospective analysis of data from adult patients who underwent single-unit CBT at our institution from November 2005 to March 2023 for whom DNA samples from recipients and donors were available. IL-2 genotyping was performed using real-time polymerase chain reaction with the TaqMan® SNP genotyping assay for rs2069762. RESULTS: A total of 143 recipient and donor pairs were included in this study. The proportion of recipient IL-2 polymorphism rs2069762 was 48 % (n = 69) for AA, 42 % (n = 60) for CA, and 10 % (n = 14) for CC. The proportion of donor IL-2 polymorphism rs2069762 was 43 % (n = 61) for AA, 48 % (n = 69) for CA, and 9 % (n = 13) for CC. In the multivariate analysis, the use of an rs2069762 CA + CC donor was associated with lower neutrophil recovery compared to an rs2069762 AA donor (hazard ratio [HR], 0.66; 95 % confidence interval [CI], 0.50-0.88; P = 0.004). Furthermore, recipients of rs2069762 CA + CC were associated with higher NRM compared to recipients of rs2069762 AA (HR, 2.32; 95 % CI, 1.01-5.34; P = 0.047). Serum IL-2 levels at 8 weeks were significantly higher in rs2069762 CA + CC recipients compared to those with rs2069762 AA recipients (P = 0.014). CONCLUSION: Our data showed that donor IL-2 polymorphism affects neutrophil recovery and recipient IL-2 polymorphism affects NRM in adults undergoing single-unit CBT. The polymorphism of IL-2 rs2069762 in recipients and donors might be associated with the clinical outcomes of single-unit CBT.

The roles of epigenetic regulation in graft-versus-host disease.

Allogeneic hematopoietic stem cell transplantation (aHSCT) is utilized as a potential curative treatment for various hematologic malignancies. However, graft-versus-host disease (GVHD) post-aHSCT is a severe complication that significantly impacts patients' quality of life and overall survival, becoming a major cause of non-relapse mortality. In recent years, the association between epigenetics and GVHD has garnered increasing attention. Epigenetics focuses on studying mechanisms that affect gene expression without altering DNA sequences, primarily including DNA methylation, histone modifications, non-coding RNAs (ncRNAs) regulation, and RNA modifications. This review summarizes the role of epigenetic regulation in the pathogenesis of GVHD, with a focus on DNA methylation, histone modifications, ncRNA, RNA modifications and their involvement and applications in the occurrence and development of GVHD. It also highlights advancements in relevant diagnostic markers and drugs, aiming to provide new insights for the clinical diagnosis and treatment of GVHD.

Single-cell RNA-sequencing reveals the transcriptional landscape of lacrimal gland in GVHD mouse model.

PURPOSE: To investigate the global transcriptional landscape of lacrimal gland cell populations in the GVHD mouse model. METHODS: Single-cell RNA sequencing and further bioinformatic analysis of dissociated lacrimal gland (LG) cells from the mouse model were performed. Parts of transcriptional results were confirmed by immunofluorescence staining. RESULTS: We identified 23 cell populations belonging to 11 cell types. In GVHD LG, the proportion of acinar cells, myoepithelial cells, and endothelial cells was remarkably decreased, while T cells and macrophages were significantly expanded. Gene expression analysis indicated decreased secretion function, extracellular matrix (ECM) synthesis, and increased chemokines of myoepithelial cells. A newly described epithelial population named Lrg1high epithelial cells, expressing distinct gene signatures, was exclusively identified in GVHD LG. The fibroblasts exhibited an inflammation gene pattern. The gene pattern of endothelial cells suggested an increased ability to recruit immune cells and damaged cell-cell junctions. T cells were mainly comprised of Th2 cells and effective memory CD8+ T cells. GVHD macrophages exhibited a Th2 cell-linked pattern. CONCLUSIONS: This single-cell atlas uncovered alterations of proportion and gene expression patterns of cell populations and constructed cell-cell communication networks of GVHD LG. These data may provide some new insight into understanding the development of ocular GVHD.

Type 2 cannabinoid receptor expression on microglial cells regulates neuroinflammation during graft-versus-host disease.

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.

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.

Impact of donor NKG2D and MICA gene polymorphism on clinical outcomes of adult and paediatric allogeneic cord blood transplantation for malignant diseases.

OBJECTIVES: NKG2D is an activating receptor expressed by natural killer (NK) and CD8+ T cells and activation intensity varies by NKG2D expression level or nature of its ligand. An NKG2D gene polymorphism determines high (HNK1) or low (LNK1) expression. MICA is the most polymorphic NKG2D ligand and stronger effector cell activation associates with methionine rather than valine at residue 129. We investigated correlation between cord blood (CB) NKG2D and MICA genotypes and haematopoietic stem cell (HSC) transplant outcome. METHODS: We retrospectively studied 267 CB HSC recipients (178 adult and 87 paediatric) who underwent transplant for malignant disease between 2007 and 2018, analysing CB graft DNA for NKG2D and MICA polymorphisms using Sanger sequencing. Multivariate analysis was used to correlate these results with transplant outcomes. RESULTS: In adult patients, LNK1 homozygous CB significantly improved 60-day neutrophil engraftment (hazard ratio (HR) 0.6; 95% confidence interval (CI) 0.4-0.9; p = .003). In paediatrics, HNK1 homozygous CB improved 60-day engraftment (HR 0.4; 95% CI 0.2-0.7; p = .003), as did MICA-129 methionine+ CB grafts (HR 1.7 95% CI 1.1-2.6; p = .02). CONCLUSION: CB NKG2D and MICA genotypes potentially improve CB HSC engraftment. However, results contrast between adult and paediatric recipients and may reflect transplant procedure disparities between cohorts.