Frequency and predictors of HIV-1 co-receptor switch in treatment naive patients.

Abstract

BACKGROUND: Determination of HIV-1 co-receptor use is a necessity before initiation of a CCR5 antagonist but the longevity of a CCR5-use prediction remains unknown. METHODS: Genotypic co-receptor tropism determination was performed in 225 newly diagnosed individuals consulting an AIDS Reference Centre. Samples were collected at diagnosis and at initiation of antiretroviral therapy or just before closure of the study for patients who did not initiate therapy. For individuals with a discordant tropism prediction on the two longitudinal samples, analysis of intermediate samples and single genome sequencing of proviral DNA was performed to confirm the tropism switch. Deep sequencing was done to identify minor CXCR4 or CCR5-using populations in the initial sample. RESULTS: Overall, tropism switches were rare (7.6%). Only a geno2pheno false positive rate of 50% and will need repeat tropism testing if initiation of maraviroc is considered and previous testing dates from more than a year before.