Allelic frequencies of host genetic variants influencing susceptibility toHIV-1 infection and disease in South African populations

Objectives: Limited information is available on the prevalence in African p opulations of host genetic polymorphisms conferring resistance to HIV-1 inf ection and disease. The objective of this study was to determine the alleli c frequencies in South African populations of the chemokine receptor gene v ariants CCR5 Delta 32, CCR5m303 and CCR2b-641 and the CXCR4 ligand gene var iant SDF1-3'A. Method: Cross-sectional study to determine the prevalence of these gene var iants in South African subjects of African and European descent. Results: The CCR5 Delta 32 genetic variant is rare in individuals of Africa n origin, having an allelic frequency of 0.1 % (n = 1247) compared with 9.8 % (n = 144) in Caucasians. The CCR5m303 mutation was not detected in Afric ans (n = 687), whereas an allelic frequency of 0.9% (n = 145) was identifie d in Caucasians. The frequency of CCR2b-641 allele was 13.1% (n = 180) in A fricans, which was significantly higher that the 7.2% (n = 146) detected in Caucasians. Finally the allelic frequency of the SDF1-3'A gene variant was only 1.0% (n = 198) in Africans compared with 19.8% (n = 145) in Caucasian s. Conclusions: These results indicate that genetic polymorphisms conferring r esistance to HIV-1 infection are rare in the South African Black population . Except for the CCR2b-641 gene variant, individuals of African origin also had a much lower prevalence of genetic variants associated with prolonged disease progression. (C) 2000 Lippincott Williams & Wilkins.