HLA-DPB1 matching in unrelated hematopoietic stem cell transplantation program contributes to a higher incidence of disease relapse

Immune Cell Infiltration Characteristics of Pigmented Villous Nodular Synovitis and Prediction of Potential Diagnostic Markers Based on Bioinformatics

Background

Pigmented villous nodular synovitis (PVNS) is a tumor-like proliferative disease characterized by impairment of daily activities, decreased quality of life, and a high recurrence rate. However, the specific pathological mechanisms are still ill-defined and controversial. The purpose of this study was to define potential diagnostic markers and evaluate immune cell infiltration in the pathogenesis of PVNS.

Method

The expression profile of GSE3698 was reanalyzed in the Gene Expression Omnibus (GEO) database. First, differentially expressed genes (DEGs) were identified using the R package “limma” and analyzed by Gene Ontology (GO) functional annotation and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment. Next, the DEGs were imported into the STRING database and Cytoscape to construct a protein–protein interaction (PPI) network. Then, cytoHubba and ROC curve analyses were used to determine potential diagnostic biomarkers of PVNS. Finally, we used CIBERSORT to estimate the proportions of 22 immune cell subtypes in PVNS and analyzed the correlation between diagnostic markers and infiltrating immune cells.

Result

We found 139 DEGs (including 93 upregulated genes and 46 downregulated genes). TYROBP, FCER1G, LAPTM5, and HLA-DPB1 were identified as potential diagnostic biomarkers of PVNS. Immune cell infiltration analysis indicated that neutrophils and M2 macrophages might be associated with the genesis and progression of PVNS. Furthermore, our correlation analysis of diagnostic markers and infiltrating immune cells found that TYROBP, FCER1G, LAPTM5, and HLA-DPB1 were positively correlated with M2 macrophage infiltration and that neutrophils, TYROBP, FCER1G, and LAPTM5 were negatively correlated with plasma cell infiltration.

Conclusions

We identified TYROBP, FCER1G, LAPTM5, and HLA-DPB1 as potential diagnostic markers for PVNS and concluded that immune cell infiltration plays an important role in the genesis and progression of PVNS.

HLA-A, -B, -C, -DRB1, -DQA1, and -DQB1 allele and haplotype frequencies defined by next generation sequencing in a population of East Croatia blood donors

Next-generation sequencing (NGS) is increasingly used in transplantation settings, but also as a method of choice for in-depth analysis of population-specific HLA genetic architecture and its linkage to various diseases. With respect to complex ethnic admixture characteristic for East Croatian population, we aimed to investigate class-I (HLA-A, -B, -C) and class-II (HLA-DRB1, -DQA1, -DQB1) HLA diversity at the highest, 4-field resolution level in 120 healthy, unrelated, blood donor volunteers. Genomic DNA was extracted and HLA genotypes of class I and DQA1 genes were defined in full-length, -DQB1 from intron 1 to 3′ UTR, and -DRB1 from intron 1 to intron 4 (Illumina MiSeq platform, Omixon Twin algorithms, IMGT/HLA release 3.30.0_5). Linkage disequilibrium statistics, Hardy-Weinberg departures, and haplotype frequencies were inferred by exact tests and iterative Expectation-Maximization algorithm using PyPop 0.7.0 and Arlequin v3.5.2.2 software. Our data provide first description of 4-field allele and haplotype frequencies in Croatian population, revealing 192 class-I and class-II alleles and extended haplotypic combinations not apparent from the existing 2-field HLA reports from Croatia. This established reference database complements current knowledge of HLA diversity and should prove useful in future population studies, transplantation settings, and disease-associated HLA screening.

Donor selection in a pediatric stem cell transplantation cohort using PIRCHE and HLA-DPB1 typing

BACKGROUND

New strategies to optimize donor selection for hematopoietic stem cell transplantation (HSCT) have mainly been evaluated in adults, but the disease spectrum requiring HSCT differs significantly in children and has consequences for the risk of complications, such as graft-versus-host disease (GvHD).

PROCEDURES

Here we evaluated whether HLA-DPB1 and Predicted Indirectly ReCognizable HLA-Epitope (PIRCHE) matching can improve donor selection and minimize risks specific for a pediatric cohort undergoing HSCT in Berlin between 2014 and 2016.

RESULTS

The percentage of HLA-DPB1-mismatched HSCT in the pediatric cohort was in line with the general distribution among matched unrelated donor HSCT. Nonpermissive HLA-DPB1 mismatches were not associated with a higher incidence of GvHD, but the incidence of relapse was higher in patients undergoing HSCT from HLA-DPB1-matched transplantations. High PIRCHE-I scores were associated with a significantly higher risk for developing GvHD in patients undergoing HSCT from nine of ten matched unrelated donors. This finding persisted after including HLA-DPB1 into the PIRCHE analysis.

CONCLUSIONS

Implementing PIRCHE typing in the donor selection process for HSCT in children could particularly benefit children with nonmalignant diseases and support further validation of PIRCHE-based donor selection in a larger number of children treated at different sites.

Genome-wide Association Study Identifies HLA-DPB1 as a Significant Risk Factor for Severe Aplastic Anemia

Severe aplastic anemia (SAA) is a rare disorder characterized by hypoplastic bone marrow and progressive pancytopenia. The etiology of acquired SAA is not understood but is likely related to abnormal immune responses and environmental exposures. We conducted a genome-wide association study of individuals with SAA genetically matched to healthy controls in discovery (359 cases, 1,396 controls) and validation sets (175 cases, 1,059 controls). Combined analyses identified linked SNPs in distinct blocks within the major histocompatibility complex on 6p21. The top SNP encodes p.Met76Val in the P4 binding pocket of the HLA class II gene HLA-DPB1 (rs1042151A>G, odds ratio [OR] 1.75, 95% confidence interval [CI] 1.50-2.03, p = 1.94 × 10-13) and was associated with HLA-DP cell surface expression in healthy individuals (p = 2.04 × 10-6). Phylogenetic analyses indicate that Val76 is not monophyletic and likely occurs in conjunction with different HLA-DP binding groove conformations. Imputation of HLA-DPB1 alleles revealed increased risk of SAA associated with Val76-encoding alleles DPB1∗03:01, (OR 1.66, p = 1.52 × 10-7), DPB1∗10:01 (OR 2.12, p = 0.0003), and DPB1∗01:01 (OR 1.60, p = 0.0008). A second SNP near HLA-B, rs28367832G>A, reached genome-wide significance (OR 1.49, 95% CI 1.22-1.78, p = 7.27 × 10-9) in combined analyses; the association remained significant after excluding cases with clonal copy-neutral loss-of-heterozygosity affecting class I HLA genes (8.6% of cases and 0% of controls). SNPs in the HLA class II gene HLA-DPB1 and possibly class I (HLA-B) are associated with SAA. The replacement of Met76 to Val76 in certain HLA-DPB1 alleles might influence risk of SAA through mechanisms involving DP peptide binding specificity, expression, and/or other factors affecting DP function.

Impact of HLA-DPB1 Matching on Outcome of Unrelated Transplant for Hematologic Malignant Diseases: A Systematic Review and Meta-analysis

OBJECTIVE

Human leukocyte antigen match is the most important donor factor affecting transplant outcome. The HLA-DPB1 mismatch on the clinical outcome of hematopoietic stem cell transplant (HSCT) is less clear. This study is the first meta-analysis to investigate the impact of HLA-DPB1 loci mismatch on clinical outcome after unrelated donor HSCT for hematologic malignant disease.

METHODS

We electronically searched the PubMed, EMBASE, Cochrane Central Register of Controlled Trials, and a related database (January 1995-December 2018) for all relevant articles. Comparative studies were carried out to investigate the impact of HLA-DPB1 loci mismatch on clinical outcome after unrelated donor HSCT, that is, the disease-free survival, engraftment, graft-vs-host disease, relapse, and transplant-related mortality (TRM). We performed a meta-analysis using Review Manager 5.3.5 software and adopted funnel plot regression to assess the publication bias.

RESULTS

A total of 1570 articles were retrieved; 21 studies including 27,852 patients were assessed. Pooled comparisons of studies found that the HLA-DPB1-mismatched group had a lower rate of disease-free survival than the DPB1-matched group and lower overall survival in non-T cell-depleted transplant than the DPB1-matched group. The DPB1-mismatched group has higher incidence of acute graft-vs-host disease (aGVHD) and severe (≥ III degree) aGVHD, lower relapse rate, and higher TRM. Moreover, compared with 1-antigen mismatch, 2-antigen mismatch in DPB1 had a higher risk of TRM and a lower relapse rate, and the nonpermissive DPB1 mismatch had significantly higher rate of severe aGvHD and lower rate of disease relapse.

CONCLUSIONS

This analysis confirmed that HLA-DPB1 has important influence on survival and transplant-related complications during unrelated donor HSCT, and HLA-DPB1 donor selection strategies have been proposed based on personalized algorithm.

HLA Matching in Unrelated Stem Cell Transplantation up to Date

Unrelated hematopoietic stem cell transplantation (HSCT) has evolved from an experimental protocol to a potentially curative first-line treatment in certain disease instances. Factors enabling this transformation were the optimization of treatment protocols and supportive care as well as the availability of a large number of donors worldwide along with the higher quality and reliability of HLA typing. The main criterion for donor selection is HLA compatibility. In this review we discuss the current clinical evidence of HLA matching in unrelated HSCT. In this context, we address methodical aspects of transplantation immunobiology research and discuss the impact of locus and resolution of HLA differences. Furthermore, we address special constellations such as unidirectional mismatches or the presence of nonexpressed alleles as well as HLA alloimmunization and describe the perspective for HLA typing and matching strategies in the future, given the implementation of novel complete or near-complete gene typing approaches using next-generation sequencing short read technology, which are now entering the standard of clinical care.