HLA-A, HLA-B and-HLA-DRB1 Alleles Diversity among Sudanese Renal & Bone Marrow Donors

Background: Human Leukocyte Antigen (HLA) is cell surface glycoproteins encoded by Major Histocompatibility Complex (MHC) gene of human genome. It plays an important role in solid organ transplant, bone morrow transplant, and auto immune diseases.This study was carried out to determine the distribution and frequencies of the HLA-A, HLA-B, and HLA-DRB1 alleles among healthy unrelated renal and bone morrow donors, and compare them with that of geographically African and Arab related populations, and also to provide a frequency data to assist in further investigations in anthropological and HLA-associated disease studies.

Materials and Method: A cross-sectional study was performed of a group of 351 unrelated renal and bone morrow donors, they were typed for HLA-A, HLA-B, and HLA-DRB1 by low resolution Polymerase Chain Reaction-Sequence Specific Primer (PCR-SSP) techniques at tissue typing laboratory, Ibn Sina Center for Kidney Diseases and Renal Transplantation (Tissue typing Laboratory)in the period from April to October 2017. The frequency for HLA-A, HLA -B, and -DRB1 alleles were defined as the percentage of the population possessing the antigen15.Samples containing one allele were considered homozygous and that allele was counted twice in the analysis.

Results: In this study considerable allele diversity was revealed at each locus. The most frequent HLA-A* alleles were A*02(54.4%), A*30(39.8%), A*68(16.8%), A*03(13.1%), A*01(11.4%) and A*24(11.4). In the HLA-B* locus were B*51(23%), B*41 (12.8%), B*39 (12.0%), B*50(12.0%), B*15:03(11.0%) and B*35(10.8%).In the HLA-DRB1, all alleles were observed. HLA-DRB1*13 (49.0%) was the most frequent allele, followed by DRB1*301(22.8%), DRB1*15(21.0%), DRB1*07(19.9%), DRB1*08(19.9%) and DRB1*11(19.4%).

Conclusions: The present study confirmed the observations on other Sudanese population studies[7], with slight difference but largely consistent in allele frequencies values,that may explain the possible differences from one area to another within one country. The present results of allele distribution and frequencies demonstrated that Sudanese population shares HLA patterns with Arab related populations specially North African and some of the neighboring African populations. Furthermore, HLA phenotype frequencies and distribution among Sudan population, if well documented, will serve many purposes including solid organ transplant, bone marrow transplant, studying HLA antigens associated diseases. It is also a valuable resource for individuals who are interested in population genetics and be helpful in the anthropologic studies.

Keywords: HLA-A, -B and DRB1, Allele frequency, Population, Sudan, Transplant.