EC Microbiology

Background: Few studies have documented serodiscordant couples sharing HLA-B at HLA-B loci and increased risk of HIV-1 transmission. This study aimed to determine the sharing of same HLA-C allele and high viral load associated with risk of HIV-1 transmission among heterosexual serodiscordant couples in Nigeria.

Methods: A total of 224 serodiscordants, 26 concordant HIV positive and 21 concordant HIV negative couples, who signed informed consent document were enrolled into this project. Extracted genomic DNA was used for HLA class 1 genotyping. Sequencing was done by Sanger method, using Biosystems™ 3130xl Genetic Analyzer. HLA-C Typing was done using Codon Express 2010. HIV-1 RNA and CD4 were analyzed. Data entry and statistical analysis was done with SPSS and Kaplan-Meier analysis.

Results: Couples age ranged from 20 - < 50 years. The most prevalent HLA-C alleles in the cohort were: C*040101 (34.5%) and C*07010 (24.2%). Serodiscordant couples sharing a single allele on HLA-C loci (HLA-C1 or C2) in the population were 55 (37.7%). Ten [10] (17.9%) serodiscordant and concordant HIV positive couples shared HLA-C alleles at C1 and C2 on HLA-C loci. Sharing HLA-C allele at group or at allele level on HLA-C loci was significant associated with HIV transmission among the couples (p < 0.009 and p < 0.001). HLA C*0701 allele was observed to be associated with high baseline HIV-1 RNA (p < 0. 003) and no association was observed with HIV-1 RNA after 6 months on ARV (P = 0.086/HLA C*04 and C*0401 were associated with high baseline HIV-1RNA after 6 months on ARV (p < 0.000 and p < 0.000).

Conclusion: Couples who shared HLA-C allele were associated with various degrees of increased HIV1-RNA and low CD4+ counts at HLA-C loci which is independently associated with increased intra-couple HIV-1 transmission amongst serodiscordant couples in Nigeria.

Keywords: HLA-C; Allele Sharing; HIV-1; Serodiscordant Couples; Heterosexual HIV-1 Transmission; Nigeria

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