Polymorphisms of chemokine receptors and its ligand alleles influencing genetic susceptibity to HIV-1 infection in eight ethnic groups in Chinese mainland

Limited genetic information is available concerning the polymorphisms of HIV-1 resistant genes in indigenous Chinese populations. The aim of this study is to identify the allelic frequencies of the chemokine and chemokine receptor genes in the Chinese mainland. Genomic DNA samples extracted from whole blood of 2318 subjects were analyzed by using PCR or PCR/restriction fragment length polymorphism (RFLP) assays, and further confirmed by direct DNA sequencing. Higher frequencies of mutant CCR2-64I (19.15%–28.79%) and SDF1-3’A (19.10% – 29.86%) alleles were found in subjects of 8 ethnic groups in the Chinese mainland. In contrast, the Δ 32 mutation in CCR5 gene occurs at a very low frequency (0.0016, n=1287) in Han population. A relatively high frequency of CCR5-wt/Δ32 heterozygotes was observed in Uygurian and Mongolian populations. No Δ32 mutation allele was detected in Tibetan and other 4 ethnic groups in Yunnan Province. There was no CCR5-m303 mutation in subjects of any ethnic group in the Chinese mainland. Our results suggest that the CCR5- Δ32 mutation is not a major resistant factor against HIV-1 infection and disease progression in Han, Tibetan and other ethnic groups in Yunnan Province. Whether higher frequencies of CCR2-641 and SDF1-3 ’A alleles constitute major genetic resistant factors or not remains to be clarified.