HLA-DPA1 gene is a potential predictor with prognostic values in multiple myeloma.

BACKGROUND: Multiple myeloma (MM) is an incurable hematological tumor, which is closely related to hypoxic bone marrow microenvironment. However, the underlying mechanisms are still far from fully understood. We took integrated bioinformatics analysis with expression profile GSE110113 downloaded from National Center for Biotechnology Information-Gene Expression Omnibus (NCBI-GEO) database, and screened out major histocompatibility complex, class II, DP alpha 1 (HLA-DPA1) as a hub gene related to hypoxia in MM. METHODS: Differentially expressed genes (DEGs) were filtrated with R package "limma". Gene Ontology (GO) enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway were performed using "clusterProfiler" package in R. Then, protein-protein interaction (PPI) network was established. Hub genes were screened out according to Maximal Clique Centrality (MCC). PrognoScan evaluated all the significant hub genes for survival analysis. ScanGEO was used for visualization of gene expression in different clinical studies. P and Cox p value < 0.05 was considered to be statistical significance. RESULTS: HLA-DPA1 was finally picked out as a hub gene in MM related to hypoxia. MM patients with down-regulated expression of HLA-DPA1 has statistically significantly shorter disease specific survival (DSS) (COX p = 0.005411). Based on the clinical data of GSE47552 dataset, HLA-DPA1 expression showed significantly lower in MM patients than that in healthy donors (HDs) (p = 0.017). CONCLUSION: We identified HLA-DPA1 as a hub gene in MM related to hypoxia. HLA-DPA1 down-regulated expression was associated with MM patients' poor outcome. Further functional and mechanistic studies are need to investigate HLA-DPA1 as potential therapeutic target.

Response to hepatitis B vaccination is co-determined by HLA-DPA1 and -DPB1.

BACKGROUND AND AIMS: No report explored the combined effects of HLA-DPA1 and -DPB1 with long-term response to hepatitis B (HB) vaccination (HBVac). The specific aims of the study were to assess the combined effects and relative contributions of DPA1 and DPB1 genes. METHODS: The cases were 152 adolescents who had undetectable (<1.0 mIU/mL) post-booster anti-HBs titers and the controls were adolescents who had residual anti-HBs ≥ 10 mIU/mL at aged 16 years (n = 207) or had detectable (≥1.0 mIU/mL) anti-HBs titers after booster HBVac (n = 481). HLA-DPA1 and -DPB1 genotypes were determined by sequence-based typing. RESULTS: HLA-DPA1*01:03:01 was correlated with lower ORs of undetectable anti-HBs titers, while -DPA1*02:02:02 and -DPB1*05:01:01 were correlated with higher ORs. The ORs for HLA-DPA1*01:03:01-DPB1*05:01:01 and DPA1*02:02:02-DPB1*protective combinatory types were significantly less than 1.0. As compared with subjects who had no protective allele, the adjusted ORs (95% CI) were 0.545 (0.328-0.906), 0.350 (0.174-0.702), and 0.122 (0.058-0.257), for subjects who had protective alleles on DPA1only, DPB1 only, and both genes, respectively. Analyses of amino acid polymorphisms showed that subjects who carried Arg81-Pro158-Val191-Pro259α + Met234ß and Gln62-Arg82α + Met234ß combinations had 4.3-to-4.6 folds of risks. CONCLUSION: Both DPA1 and DPB1 genes contribute to the persistence of immunological response to primary infantile HBVac. The effects of HLA-DP risk alleles were dominated by the protective alleles and there were significant gene-gene interactions. Our findings provide evidences for the design of more potent HB vaccine.

Identification of the novel HLA-DPA1*02:01:01:06 allele in a Saudi individual.

HLA-DPA1*02:01:01:06 differs from HLA-DPA1*02:01:01:01 by a single nucleotide substitution (T → G) at position 948.

Identification of the novel HLA-DPA1*01:03:01:12 allele in a Saudi individual.

HLA-DPA1*01:03:01:12 differs from HLA-DPA1*01:03:01:01 by a single nucleotide substitution (G → C) at position 4239.

Genetic polymorphism of rs9277535 in HLA-DP associated with rheumatoid arthritis and anti-CCP production in a Chinese population.

HLA-II molecules are critical in triggering human immune response, especially in activating CD4+ T cells. HLA-DP, belonging to HLA-II molecules, draws increasing attention for its role in presentation of viral antigen and autoantigen to T cells. Researches reported single nucleotide polymorphism (SNP) of HLA-DP associated with HBV infection and autoimmune diseases such as SLE. However, little is known about the relationship between HLA-DP and rheumatoid arthritis (RA). Rs9277535 is located in 3' UTR region of HLA-DPB1, a subunit of HLA-DP, and was reported to affect HLA-DP mRNA expression. In the present study, we explored the relationship between gene polymorphism of rs9277535 in HLA-DPB1 and RA susceptibility and progression. Samples from 254 patients with RA and 391 age- and sex-matched healthy controls were collected and genotyped by a polymerase chain reaction-high-resolution melting (PCR-HRM) assay. Serological tests (anti-CCP, rheumatoid factor, C-reactive protein, anti-keratin antibody) were detected by laboratory assays. Strong association was observed between SNP rs9277535 in HLA-DP and RA susceptibility (allele frequency distribution: OR = 1.409, 95%CI = 1.121-1.773, P = 0.004). Further validation was provided by disease model analysis (recessive model: OR = 1.889, 95%CI = 1.194-2.990, P = 0.008; dominant model: OR = 1.464, 95%CI = 1.050-2.041, P = 0.025; additive model: OR = 2.208, 95%CI = 1.335-3.652, P = 0.003). Allele A was correlated to increased risk of RA. Serological test results demonstrated patients carrying allele A of rs9277535 had elevated serum anti-CCP antibody level. The present study provided evidence that HLA-DP gene polymorphism associated with RA susceptibility. Allele A of rs9277535 in HLA-DP correlated to increased risk of RA and elevated serum anti-CCP level.

Role of HLA-DP and HLA-DQ on the clearance of hepatitis B virus and the risk of chronic infection in a multiethnic population.

BACKGROUND & AIMS: HBV infection exhibits geographical variation in its distribution in South America. While HBV rates are low in central Argentina, the north-western region exhibits intermediate HBV rates. Unfortunately, the reasons that could explain this difference are still unknown. METHODS: A total of 1440 Argentines were recruited and grouped into HBV patients, HBV-resolved individuals and healthy controls. Genetic ancestry was assessed by analysis of biparental lineages and ancestry autosomal typing. SNPs of HLA-DPA1 (rs3077), HLA-DPB1 (rs9277542), HLA-DQB1 (rs2856718) and HLA-DQB2 (rs7453920) were determined, and HBV genotyping was performed by phylogenetic analysis in HBV patients. RESULTS: Native American ancestry prevailed in the north-western region when compared with central Argentina (P<.0001). However, no differences were observed among the three groups of each region. The distribution of HBV genotypes revealed significant differences (P<.0001). Three SNPs (rs3077, rs9277542 and rs7453920) showed a significant association with protection against chronic HBV and viral clearance in both regions. The remaining SNP showed a significant association with susceptibility to chronic HBV. The frequency rates of rs3077-T, related to protection against chronic HBV and viral clearance, were lower in north-western Argentina when compared with central Argentina. The same uneven frequency rates were observed for SNP rs9277542. CONCLUSIONS: This is the first study addressing the associations between the HLA-DP and HLA-DQ loci and the protection against chronic HBV and viral clearance in a multiethnic South American population. The uneven distribution of HLA-DP and HLA-DQ supports the HBV epidemiological differences observed in these two regions of Argentina with dissimilar ancestry genetic background.

Kidney Transplantation With Ultralong-Term (42 Years) Survival of a 100-Year-Old Graft.

BACKGROUND: In kidney transplantation, long-term graft survival has improved over the last few decades. Study to understand ultralong-term graft survival with graft functioning is rare, but a few researchers have tried to explain the factors involved in long-term graft survival. In this report, we explore the predictive factors that can be involved in ultralong-term graft survival. MATERIAL AND METHODS: Immunologic evaluations of the patients were performed using crossmatch (XM), serological, and high-resolution HLA typing for 8 loci. A transplant recipient was treated with azathioprine as immunosuppressive monotherapy for 42 years. Donor-specific antibodies (DSAs) were identified using panel reactive antibody single antigen beads (PRA-SAB) followed by EpVix and Matchmaker epitope analysis to define the immunogenic mismatch eplets. RESULTS: The patient and donor were haploidentical for 7 loci and identical at the HLA-DPA1* locus. Among 61 identified eplet mismatches, DSAs were not detected against 59 eplets after 42 years of exposure to the patient's immune system with the exceptions of antibodies against the public eplets 9Y and 9YL from allele HLA-DPB1*03:01, and the transplanted kidney exhibited preserved structures. CONCLUSION: The transplanted kidney has the preserved structure based on magnetic resonance imaging, the 2 DSAs were not deleterious to the graft until now, and the eplet mismatches were considered acceptable. The patient is in good clinical condition living with a 100-year-old graft, a serum creatinine level of 1.5 mg/dL, and an estimated glomerular filtration rate of 50 mL/1.72 m2.

Complete exon 2 sequence of the HLA-DPA1*03:01 allele by sequence-based typing.

Completion of the first 20 nucleotides of exon 2 of DPA1*03:01 allele.

Protective effects of HLA-DPA1/DPB1 variants against Hepatitis B virus infection in an Indonesian population.

Human leukocyte antigen (HLA) DPA1/DPB1 variants have been reported to influence Hepatitis B virus (HBV) infection. HLA-DPA1/DPB1 plays a pivotal role in antigen presentation to CD4(+) helper T cells and influences the outcome of HBV infection. To investigate the influence of HLA-DP variants on the outcome of HBV infection in an Indonesian population where it has the third-highest prevalence of HBV infection worldwide, we performed a case-control study of 686 participants, including patients with HBV-related advanced or nonadvanced liver disease, patients with spontaneously resolved HBV, and healthy controls. Single-nucleotide polymorphisms in HLA-DPA1 (rs3077) and HLA-DPB1 (rs3135021, rs9277535, and rs228388) were genotyped using real-time TaqMan® genotyping assays. Because rs2281388 deviated from Hardy-Weinberg equilibrium, it was excluded from subsequent analyses. The results of logistic regression analyses showed that the HLA-DPB1 rs9277535 variants were associated with a reduced risk of persistent HBV infection (odds ratio [OR] 0.70, 95% confidence interval [95% CI] 0.52-0.96, P=0.026, additive genetic model; OR 0.60, 95% CI 0.38-0.96, P=0.033, dominant genetic model). The HLA-DPA1 rs3077 variant was associated with a protective effect increasing the spontaneously resolved HBV infection (OR 0.64, 95% CI 0.41-0.98, P=0.039, dominant genetic model). By contrast, the HLA-DPB1 rs3135021 variant was not associated with the outcome of HBV infection, including susceptibility, spontaneously resolved, or disease progression. Combinations of haplotype markers were also associated with HBV susceptibility (CA for rs3077-rs9277535, OR 0.57, 95% CI 0.36-0.92, P=0.021; GA for rs3135021-rs9277535, OR 0.56, 95% CI 0.36-0.86, P=0.0087). In conclusion, these findings confirm that HLA-DPA1/DPB1 variants were associated with the outcomes of HBV infection in an Indonesian population.

Unintended Consequences of the New National Kidney Allocation Policy in the United States.

The new national Kidney Allocation System of the Organ Procurement and Transplantation Network (OPTN), effective as of December 4, 2014, was designed to improve the chances of transplanting the most highly sensitized patients on the waitlist, those with calculated panel reactive antibody values of 98%, 99% and 100%. Recently, it was suggested that these highly sensitized patients will experience inequitable access, given the reported high prevalence of antibodies to HLA-DP, and the fact that only about 1/3 of deceased donors are typed for HLA-DP antigens. Here we report that 320/2948 flow cytometric crossmatches performed for the Northwestern transplant program over the past 28 months were positive solely due to HLA-DP donor-specific antibodies (11%; 16.5% of patients with HLA antibodies-sensitized patients). We further show that 58/207 (12%) HLA-DR serologically matched donor-recipient pairs had a positive B cell flow crossmatch due to donor-specific HLA class II antibodies, and 2/34 (6%) serologic zero-HLA-A-B-DR mismatch had a positive flow crossmatch due to HLA-DSA. We therefore provide information regarding the necessity and importance of complete donor HLA typing including both chains of the HLA-DP antigen (encoded by HLA-DPA1 and HLA-DPB1) at the time of organ offer.

Risk associations between HLA-DPB1 T-cell epitope matching and outcome of unrelated hematopoietic cell transplantation are independent of HLA-DPA1.

HLA-DP antigens are beta-alpha heterodimers encoded by polymorphic HLA-DPB1 and -DPA1 alleles, respectively, in strong linkage disequilibrium (LD) with each other. Non-permissive unrelated donor (UD)-recipient HLA-DPB1 mismatches across three different T-cell epitope (TCE) groups are associated with increased mortality after hematopoietic SCT (HCT), but the role of HLA-DPA1 is unclear. We studied 1281 onco-hematologic patients after 10/10 HLA-matched UD-HCT facilitated by the National Marrow Donor Program. Non-permissive mismatches defined solely by HLA-DPB1 TCE groups were associated with significantly higher risks of TRM compared to permissive mismatches (hazard ratio (HR) 1.30, confidence interval (CI) 1.06-1.53; P=0.009) or allele matches. Moreover, non-permissive HLA-DPB1 TCE group mismatches in the graft versus host (GvH) direction significantly decreased the risk of relapse compared to permissive mismatches (HR 0.55, CI 0.37-0.80; P=0.002) or allele matches. Splitting each group into HLA-DPA1*02:01 positive or negative, in frequent LD with HLA-DPB1 alleles from two of the three TCE groups, or into HLA-DPA1 matched or mismatched, did not significantly alter the observed risk associations. Our findings suggest that the effects of clinically non-permissive HLA-DPB1 TCE group mismatches are independent of HLA-DPA1, and that selection of donors with non-permissive DPB1 TCE mismatches in GvH direction might provide some protection from disease recurrence.

Genetic variants in human leukocyte antigen-DP influence both hepatitis C virus persistence and hepatitis C virus F protein generation in the Chinese Han population.

Chronic hepatitis C is a serious liver disease that often results in cirrhosis or hepatocellular carcinoma. The aim of this study was to assess the association of human leukocyte antigen-DP (HLA-DP) variants with risk of chronic hepatitis C virus (HCV) or anti-F antibody generation. We selected two single nucleotide polymorphisms (SNPs) in a region including HLA-DPA1 (rs3077) and HLA-DPB1 (rs9277534) and genotyped SNPs in 702 cases and 342 healthy controls from the Chinese population using TaqMan SNP genotyping assay. Moreover, the exon 2 of the HLA-DPA1 and HLA-DPB1 genes were amplified and determined by sequencing-based typing (SBT). The results showed that rs3077 significantly increased the risk of chronic HCV infection in additive models and dominant models (odds ratio (OR) = 1.32 and 1.53). The rs3077 also contributed to decrease the risk of anti-F antibody generation in additive models and dominant models (OR = 0.46 and 0.56). Subsequent analyses revealed the risk haplotypes (DPA1*0103-DPB1*0501 and DPA1*0103-DPB1*0201) and protective haplotypes (DPA1*0202-DPB1*0501 and DPA1*0202-DPB1*0202) to chronic HCV infection. Moreover, we also found that the haplotype of DPA1*0103-DPB1*0201 and DPA1*0202-DPB1*0202 were associated with the anti-F antibody generation. Our findings show that genetic variants in HLA-DP gene are associated with chronic HCV infection and anti-F antibody generation.

Early acute antibody-mediated rejection of a negative flow crossmatch 3rd kidney transplant with exclusive disparity at HLA-DP.

Donor-specific alloantibodies (DSA) to HLA-DP may cause antibody-mediated rejection (AMR), especially in re-transplants. We describe the immunization history of a patient who received 3 kidney transplants; the 3rd kidney was completely matched except at DPA1 and DPB1. Prior to the 3rd transplant, single antigen bead analysis (SAB) showed DSA reactivity against DPA1 shared by the 1st and 3rd donors, but B and T flow crossmatch (FXM) results were negative. Within 11 days the 3rd transplant underwent acute C4d+ AMR which coincided with the presence of complement (C1q)-binding IgG1 DSA against donor DPA1 and DPB1. Using HLAMatchmaker and SAB, we provide evidence that eplet (epitope) spreading on DPA1 and eplet sharing on differing DPB1 alleles of the 1st and 3rd transplants was associated with AMR. Since weak DSA to DPA1/DPB1 may induce acute AMR with negative FXM, donor DPA1/DPB1 high resolution typing should be considered in sensitized patients with DP-directed DSA.

Allorecognition of HLA-DP by CD4+ T cells is affected by polymorphism in its alpha chain.

Alloreactivity to HLA-DP molecules, class II heterodimers of an oligomorphic alpha and a polymorphic beta chain, is increasingly being studied due to its relevance in clinical transplantation. We hypothesized that not only polymorphisms in the peptide binding groove encoded by exon 2 of HLA-DPB1, but also in other regions of the molecule and the alpha chain, could play a role in CD4+ T cell allorecognition. To test this possibility, we comparatively investigated CD4+ T cell allorecognition, measured by upregulation of the activation marker CD137, against HLA-DPB1*13:01, *05:01, *03:01, *17:01 or their allele counter parts DPB1*107:01, *135:01, *104:01, *131:01, with identical exon 2 sequences but polymorphism in exons 1, 3 or 4, in the context of different HLA-DPA1 (DPA1) polymorphisms (DPA1*01:03 and *02:01). No significant differences in CD4+ T cell allorecognition levels could be demonstrated for any of the beyond exon 2 DPB1 variants studied. Interestingly, however, the mean fold change in CD4+ CD137+ cells was significantly higher when the target shared at least one DPA1 allele with the allogeneic stimulator, compared to a distinct DPA1 background (1.65 vs 0.23, P<0.005). Structural homology modeling suggested specific amino acid residues in the alpha chain, in particular position 31, to impact CD4+ T cell allorecognition of HLA-DP. Our data argue against a significant role of beyond exon 2 DPB1 polymorphisms for T cell alloreactivity, but show relevance of DPA1 polymorphism in this mechanism. These new findings impact HLA matching strategies in unrelated stem cell transplantation.

Characterization of the novel HLA-DPA1*02:05 allele identified by sequence-based typing.

The novel HLA-DPA1*02:05 variant allele differs from the closest allele DPA1*02:02:02.

Identification of three novel human leukocyte antigen alleles, HLA-B*58:43, HLA-C*03:190, and HLA-DPA1*01:12, in an East African cohort.

Three novel human leukocyte antigen (HLA) alleles were identified using a sequence-based typing of HLA class I and class II alleles of 1867 participants from a male circumcision cohort in Kenya. The new alleles were first identified by sequencing and then confirmed by cloning the polymerase chain reaction (PCR) products and sequencing multiple clones. HLA-B*58:43 was identical to HLA-B*58:02 with the exception of a nucleotide change at codon 125 in exon 3 (GCC→ACC), and resulted in the amino acid change from Alanine to Threonine. HLA-C*03:190 was identical to HLA-C*03:02:01 with the exception of a nucleotide change at codon 131 in exon 3 (CGC→TGC), and resulted in the amino acid change from Arginine to Cysteine. HLA-DPA1*01:12 was identical to HLA-DPA1*01:03:01:01 with the exception of a nucleotide change at codon 66 in exon 2 (TTG→TCG), and resulted in the amino acid change from Leucine to Serine.

Genetic study confirms association of HLA-DPA1(∗)01:03 subtype with ankylosing spondylitis in HLA-B27-positive populations.

The association of human leukocyte antigen (HLA)-B27 with ankylosing spondylitis (AS) has been known for over 38 years. However, it is not the only gene associated with AS. The aim of this study was to confirm the association of HLA markers around HLA-DPA1/DPB1 region with AS in HLA-B27 positive populations. Five SNPs (rs422544, rs6914849, rs92777535, rs3128968 and rs2295119) from the HLA-DPA1/DPB1 region were genotyped in 340 individuals HLA-B27-positive from Portugal (137 AS patients and 203 healthy controls). Characterizations of HLA-DPA1/DPB1 alleles were also performed. rs422544 revealed a significant association with AS (P<0.05) and sliding windows (SW) analysis showed association of some groups of adjacent SNPs within HLA-DPA1/DPB1 region with AS (P<0.05). We also found association of the HLA-DPA1(∗)01:03 allele with AS (P<0.05). This is the first study that confirms the association of HLA markers and haplotypes around HLA-DPA1 and HLA-DPB1 with AS.

Characterization of a novel variant allele HLA-DPA1*02:02:05, identified in a Chinese Han individual.

The novel HLA-DPA1*02:02:05 allele differs from the closest allele DPA1*02:02:01 by single-nucleotide change.

Host genetic factors affecting spontaneous HBsAg seroclearance in chronic hepatitis B patients.

Spontaneous clearance of hepatitis B surface antigen (HBsAg) in chronic hepatitis B (CHB) patients usually indicates a remission of hepatitis activity and a favorable outcome. Two single nucleotide polymorphisms (SNP), rs3077 near HLA-DPA1 region and rs9277535 near HLA-DPB1 region, have been shown to be associated with HBV persistence after acute HBV infection. However, little is known about the impact of these 2 SNPs on spontaneous HBsAg clearance in CHB patients. In this case-control study, a total of 100 male HBeAg-negative chronic HBV carriers who cleared HBsAg spontaneously (case group) and 100 age-matched HBeAg-negative male patients with persistent HBsAg positivity (control group) were enrolled. We investigated the relationship between these 2 SNPs and HBsAg clearance. There was a higher frequency of rs9277535 non-GG genotype in the case group (57% vs. 42%). Patients with rs9277535 non-GG genotype had a higher chance to clear HBsAg [Odds ratio (OR): 1.83, 95% confidence interval (CI): 1.04∼3.21, P = 0.034]. Compared to GG haplotype of rs3077 and rs9277535, GA haplotype had a higher chance of achieving spontaneous HBsAg loss (OR: 2.17, 95% CI: 1.14∼4.16, P = 0.030). In conclusion, rs9277535 non-GG genotype is associated with a higher likelihood of spontaneous HBsAg seroclearance in CHB patients.

Effect of host and viral factors on hepatitis B e antigen-positive chronic hepatitis B patients receiving pegylated interferon-α-2a therapy.

BACKGROUND: Pegylated interferon (PEG-IFN)-α-2a improves the hepatitis B e antigen (HBeAg) seroconversion rate in HBeAg-positive chronic hepatitis B patients. However, baseline factors predicting favourable responses to PEG-IFN-α-2a remain largely unknown. METHODS: A total of 115 HBeAg-positive chronic hepatitis B patients who had a pre-therapy serum alanine aminotransferase (ALT) level over two times the upper limit of normal and received PEG-IFN-α-2a for 6-12 months were consecutively enrolled according to the local reimbursed guidelines. HBeAg seroconversion and combined response defined as HBeAg seroconversion, HBV-DNA level <20,000 IU/ml as well as ALT normalization at 6 months off therapy were primary and secondary therapeutic end points, respectively. Baseline viral factors, including viral load, genotype and major sequences of precore stop codon/basal core promoter (BCP), and host factors, including three single nucleotide polymorphisms among the HLA-DPA1, HLA-DPB1 and IL28B regions, were determined to correlate with therapeutic end points. RESULTS: HBeAg seroconversion and combined response rates were 26.1% and 18.3%, respectively. By multivariate analysis, BCP mutation (OR 8.04, 95% CI 2.00-32.28) and rs3077 G/G genotype (OR 3.49, 95% CI 1.12-10.84) were associated with a higher HBeAg seroconversion rate; BCP mutation (OR 9.28, 95% CI 1.92-44.99) and baseline viral load <2 × 10(6) IU/ml (OR 4.78, 95% CI 1.37-16.69) were associated with a higher combined response rate. CONCLUSIONS: BCP mutation is associated with higher HBeAg seroconversion and combined response rates at 6 months off therapy in HBeAg-positive chronic hepatitis B patients treated with PEG-IFN-α-2a. Genetic variants in the HLA-DPA1 region may also affect treatment-induced HBeAg seroconversion.