HLA haplotype diversity in the South Indian population and its relevance

BackgroundSouth India (SI) is the area encompassing India's states of Andhra Pradesh, Karnataka, Kerala, Telangana, and Tamil Nadu as well as the union territories of Lakshadweep and Pondicherry. South Indians are heterogeneous population with different ways of life, language, and physical appearance. A majority of Indians from the southern region speak one of the languages: Tamil, Telugu, Kannada, Malayalam, or Tulu. A large number of south-Indians have now migrated to different parts of the world and often need human leukocyte antigen (HLA) matched donors for treatment of different disorders. Knowledge of allele and haplotype frequencies of the HLA system is important in the search for unrelated bone marrow donors. The South Indian population is very heterogeneous and the HLA system is highly informative of populations because of the high level of polymorphisms. We investigated distribution of HLA A, B and DRB1 loci in five linguistic groups from SI.Materials & methodsAll the data were collected from the Marrow Donor Registry India (MDRI) which has pool of volunteer stem cell donors from these linguistic groups. DNA extracted from EDTA-blood sample of recruited donors, and HLA typing done using Luminex XMAP technology and sequence specific primer (SSP) technique at low–intermediate resolution. Graph pad InStat 3 and the software from National Marrow Donor Program (NMDP) were used for determining p values and haplotype frequency respectively.ResultsMDRI donors belonging to these five linguistic groups namely Tamil, Telugu, Tulu, Kannada, and Malayalam speaking donors were analyzed. The most common haplotypes were A*01-B*57-DRB1*07, A*33-B*44-DRB1*07, A*02-B*40-DRB1*15, A*24-B*07-DRB1*15, A*24-B*40-DRB1*15. A few unique haplotypes were seen as most common haplotype in each linguistic group.ConclusionEach linguistic group has unique haplotypes along with a few common haplotypes. In order to adequately represent the Indian population on the registry, each linguistic group should be targeted for donor recruitment. This would enable a better chance for any patient to find a matched unrelated donor.