HLA class I and class II allele and haplotype distribution in the Venezuelan population.

Population studies represent an integral part, and a necessary link in a complex chain of host-pathogen interactions, disease pathogenesis, and major histocompatibility complex polymorphism. HLA class I and class II allele and haplotype distributions among Venezuelan mestizos were determined. Genes of Mongoloid, Negroid, and Caucasoid origin have created a distinctive human leukocyte antigen (HLA) genetic profile in this hybrid mestizo population that will influence HLA and disease association studies. The predominant HLA-B DQA1 DQB1 DRB1 haplotype is HLA-B44 DQA1*0201 DQB1*0201 DRB1*0701 (5.3%). It is noteworthy that the HLA-A3 B7 DR2 and the HLA-A1 B8 DR3 linkage groups, which are part of conserved or ancestral haplotypes, the last one associated with a wide range of autoimmune diseases and immune abnormalities in apparently healthy subjects, show low incidence among Venezuelan mestizos. This fact may be useful for future HLA and disease association studies and for localization of genes involved in immune regulation associated with these haplotypes.