Impact of early antiretroviral therapy on the performance of HIV rapid tests and HIV incidence assays.

Publication Type:

Journal Article

Source:

Journal of acquired immune deficiency syndromes (1999) (2017)

Abstract:

BACKGROUND: Antiretroviral therapy (ART) can down-regulate antibody responses to HIV infection. We evaluated the impact of early vs. delayed ART on the performance of HIV diagnostic and incidence assays.

METHODS: Samples were obtained from 207 participants in the HPTN 052 trial who were stably suppressed on ART for ≥4 years (Malawi sites; pre-ART CD4 cell count 350-550 cells/mm [early ART arm, N=180] or <250 cells/mm or an AIDS-defining illness [delayed ART arm, N=27]). Samples were tested with two HIV rapid tests and two HIV incidence assays; selected samples were also tested with two 4-generation immunoassays and a Western blot (WB) assay. A pre-ART sample was analyzed if the follow-up sample had a false negative or weakly-reactive rapid test result, or had an incidence assay result indicative of recent infection (false-recent result).

RESULTS: Ten (4.8%) samples had a non-reactive or weakly-reactive rapid test result (7/180 early ART arm, 3/27 delayed ART arm, p=0.13); one sample had non-reactive 4-generation assay results and three had indeterminate WBs. Forty (18.9%) samples had a false-recent incidence assay result; 16 (7.8%) had false-recent results with both incidence assays. Baseline samples had stronger rapid test and WB bands, higher 4-generation assay signal-to-cutoff values, and fewer HIV incidence assay results indicative of recent infection.

CONCLUSIONS: False-negative/weakly-reactive HIV rapid tests and false-recent HIV incidence assay results were observed in virally-suppressed individuals, regardless of pre-ART CD4 cell count. Down-regulation of the antibody response to HIV infection in the setting of ART may impact population-level surveys of HIV prevalence and incidence.