Decreased seroreactivity in individuals initiating antiretroviral therapy during acute HIV infection

Antiretroviral therapy (ART) during acute HIV infection (AHI) interrupts viral dynamics and may delay the emergence of serological markers targeted by current HIV screening and confirmatory assays, thus creating challenges for correctly classifying HIV infection status. The performance of three HIV antigen/antibody combination (HIV Ag/Ab Combo) assays (the Bio-Rad GS, Abbott Architect, and Bio-Rad BioPlex 2200 assays) was evaluated with samples collected from RV254/South East Asia Research Collaboration in HIV 010 (RV254/SEARCH010) study (Bangkok, Thailand) participants at weeks 12 and 24 following the initiation of ART at Fiebig stage I (FI) (n = 23), FII (n = 39), or FIII/IV (n = 22). Supplemental, confirmatory testing was performed by the Geenius HIV 1/2 and HIV-1 Western blot assays (Bio-Rad). Samples from 30 untreated, HIV-1-infected individuals demonstrated robust HIV Ag/Ab Combo assay reactivity with well-developed HIV-1 Western blotting profiles by 24 weeks after infection. In contrast, 52.2% of samples from individuals initiating ART at FI, 7.7% of samples from individuals initiating ART at FII, and 4.5% of samples from individuals initiating ART at FIII/IV were nonreactive by the HIV Ag/Ab Combo assays, with 36.4 to 39.1% of samples having low signal-to-cutoff (S/CO) results by the Architect and BioPlex assays (S/CO < 10). Seroreversion from a reactive to a nonreactive status was observed in 10 individuals initiating ART at FII and 3 individuals initiating ART at FIII/IV. The Geenius and HIV-1 Western blot assay results were negative or indeterminate for 73.9% and 69.6% of individuals, respectively, treated at FI; 50.0% and 26.3% of individuals, respectively, treated at FII; and 54.5% and 40.9% of individuals, respectively, treated at FIII/IV. Virologic suppression of HIV-1 by ART during AHI impedes seroconversion to biomarkers of infection, limiting the utility of HIV Ag/Ab Combo and supplemental, confirmatory assays for infection status determination.