HIV-1 primary infection in two pairs of patients: difference in variants transmitted and clinical follow-up

Recent observations have indicated that during HIV transmission the transmitted viruses represent a minor variant in the blood of the donor irrespective of the route of transmission (sexual, vertical or parenteral contact). Several reports have also confirmed the presence of a virus population homogeneous for the V3 region of the HIV-1 env gene in recently infected individuals. The mechanisms and consequences of selection of a particular HIV-1 variant from a heterogenous viral population upon transmission remain to be elucidated. This study describes two cases of sexual transmission of HIV-1 with either transmission of a minor or major variant from the donors. Nucleotide sequence analysis of the V3 env region, p17 gag gene and reverse transcriptase (RT) coding region was carried out on proviral DNA from the peripheral blood mononuclear cells (PBMC) of both recipients and their respective donors following acute seroconversion (D1 arrow right R1 pair, heterosexual contact; D2 arrow right R2 pair, homosexual contact). This study shows that a minor as well as major HIV-1 variants can be transmitted during sexual transmission. Furthermore, a marked contrast in the viral and clinical characteristics following acute HIV-1 seroconversion was observed in both donor-recipient cases reported.