Objective To investigate the impact of HLA-A antigens carrying Bw4 epitopes on disease course of HIV-1 infection.Methods Three hundred and forty subjects chronically infected with HIV-I were recruited and their HLA-A and B alleles were genotyped with sequence-based high resolution typing assay.HLA-Bw genotypes of these HIV-1 infected subjects were determined and their association with CD+4 T cell counts and viral load were analysed.Results When compared with subjects canting no Bw4 epitopes in HLA-A and HLA-B loci (OBw4) (median of CD+4 T cell counts:294/μ1;plasma viral load median 6.29×104 copies/ml),CD+4 T cell counts in subjects with genotypes of 1Bw4-A and 2Bw4-AA were comparable (307 and 308/μ1,respectively),but higher viral load (1.53×105 and 2.68×105 copies/ml,respectively) was observed.In subjects with Bw4 epitopes in HLA-B alleles but no in HLA-A,significantly higher CD+4 T cell counts (417/μ1,P=0.013) and lower viral load (2.10×104 copies/ml,P=0.007) were observed compared with those without Bw4 in HLA-A and HLA-B.Conclusion HLA-B antigens carrying Bw4 epitope were protective in HIV-1 infection by maintaining higher CD+4 T cell counts and lower viral load,but such protective effect was not observed in HLA-A antigens earring Bw4 epitope.