HLA class I alleles frequencies in the Syrian population

Methodological Study on the Establishment of HLA/HPA Gene Bank of Platelet Donors and Its Clinical Application

The current study aimed at establishing a large-scale platelet donor database with known HPA and HLA genotypes in Ningbo, to provide matched platelets for the clinic and prevent the occurrence of ineffective immune platelet transfusion refractoriness (PTR). The platelet banks of clinical donor wtih HLA-A, HLA-B, HPA1, HPA2, HPA3, HPA4, HPA5, HPA6, HPA10, HPA15 and HPA21 genotyps were established. Meanwile, the platelet gene matching was performed on the donor. It was found that there were phenotype polymorphisms in 1000 donnors with HPA1, HPA2, HPA3, HPA4, HPA5, HPA6, HPA10, HPA15 and HPA21 genotyps, and allel polymorphism distribution in donnors with HPA1, HPA2, HPA3, HPA4, HPA5, HPA6, HPA15, HPA21 genotyps. The frequency of HPA10 was a gene, and not b gene, showing a single linear distribution. The HPA 2, HPA3, HPA15 system were the most polymorphic with three phenotypes: aa, ab, bb. In the HLA-A allele, the highest frequency is A*11:01 (24.25%). There were 13 alleles that were greater than 1%, such as A*24:02, A*02:01, A*33:03, and the accumulated frequency reached 96.20%. In the HLA-B allele, the highest gene frequency was B*40:01 (13.40%). There were 24 alleles that were greater than 1%, such as B*46: 01, B*58: 01, B*15: 01, and the accumulated frequency reached 91.60%. Platelet antibody cross matching was performed on 100 blood samples from patients with thrombocytopenia after multiple platelet transfusions. The number of consistent samples was 46 (46%). Twenty patients were transfused with platelet cross matching. Among them, 18 patients had obvious improvement in clinical symptoms and good hemostatic effect after transfusion, which was judged to be effective. Platelet donor HPA and HLA-A, B antigen genotyping database provided patients with individual appropriate platelets, and provided the effectiveness of immune platelet infusion ensuring effective platelet transfusion.

Distribution of HLA-B Alleles and Haplotypes in Qatari: Recommendation for Establishing Pharmacogenomic Markers Screening for Drug Hypersensitivity

Human leukocyte antigen (HLA) proteins are present at the cellular surface of antigen-presenting cells and play a crucial role in the adaptive immune response. Class I genes, specifically certain HLA-B alleles, are associated with adverse drug reactions (ADRs) and are used as pharmacogenetic markers. Although ADRs are a common causes of hospitalization and mortality, the data on the prevalence of HLA-B pharmacogenetics markers in Arab countries are scarce. In this study, we investigated the frequencies of major HLA-B pharmacogenomics markers in the Qatari population. Next-generation sequencing data from 1,098 Qatari individuals were employed for HLA-B typing using HLA-HD version 1.4.0 and IPD-IMGT/HLA database. In addition, HLA-B pharmacogenetics markers were obtained from the HLA Adverse Drug Reaction Database. In total, 469 major HLA-B pharmacogenetic markers were identified, with HLA-B*51:01 being the most frequent pharmacogenetic marker (26.67%) in the Qatari population. Moreover, HLA-B*51:01 is associated with phenytoin- and clindamycin-induced ADRs. The second most frequent pharmacogenetic marker was the HLA-B*58:01 allele (6.56%), which is associated with allopurinol-induced ADRs. The third most frequent pharmacogenetic marker was the HLA-B*44:03 allele, which is associated with phenytoin-induced ADRs. The establishment of a pharmacogenetics screening program in Qatar for cost effective interventions aimed at preventing drug-induced hypersensitivity can be aided by the highly prevalent HLA-B pharmacogenetic markers detected here.

HLA major allele group frequencies in a diverse population of the Free State Province, South Africa

Background

Human Leucocyte Antigens (HLA) play a vital role in disease pathogenesis and transplant rejection. HLA-typing is a useful tool in predicting disease progression and to identify potential organ donors. Due to human migration and known ethnic variation, frequent targeted HLA sequencing of specific populations is crucial to increase their representation in global reference panels.

Materials and methods

We performed a retrospective file audit of all HLA-typings done in our setting from 2005-2019. We discuss data for the major HLA-A, HLA-B, HLA-C, and HLA-DRB1 allele groups.

Results

Overall, the most common allele groups were HLA-A∗02, HLA-B∗15, HLA-C∗07 and HLA-DRB1∗03. For the African descent group, the most common alleles were HLA-A∗30, HLA-B∗15, HLA-C∗07 and HLA-DRB1∗03. For the European descent group, the most common alleles were HLA-A∗02, HLA-B∗07, HLA-C∗07 and HLA-DRB1∗15. For the mixed ancestry group, the most common allele groups were HLA-A∗02, HLA-B∗15, HLA-C∗02 and HLA-DRB1∗13. HLA-B∗44 was identified as the most common allele group in patients with renal failure.

Discussion and conclusion

The significant variation within the HLA frequencies between the different ethnic groups highlights the value of population-specific HLA-typing. Furthermore, the identification of HLA-B∗44 as a prominent HLA in our renal failure population warrants in-depth investigation of this group.