Clinical infectious diseases : an official publication of the Infectious Diseases Society of America 2016 6 17() pii

Abstract
BACKGROUND
 Third- and fourth-generation immunoassays are widely used in the diagnosis of human immunodeficiency virus (HIV) infection. Antiretroviral therapy (ART) during acute HIV infection (AHI) may impact HIV-specific antibodies, with failure to develop antibody or seroreversion. We report on the ability of diagnostic tests to detect HIV-specific antibodies in Thai participants initiating ART during AHI.

METHODS
 Participants with detectable plasma HIV-RNA but non-reactive HIV-specific IgG, enrolled in an AHI study were offered immediate initiation of ART. Participants were tested at initiation, 12 and 24 weeks following treatment using standard second-, third- and fourth-generation immunoassays and Western blot.

RESULTS
 Participants (N=234) initiating ART at a median of 19 days (range 1-62) from HIV exposure demonstrated different frequencies of reactivity prior to and following 24 weeks of ART depending on the immunoassay. Third-generation immunoassay non-reactivity prior to ART was 48%, which decreased to 4% following ART (p<0.001). Fourth-generation immunoassay non-reactivity was 18% prior to ART and 17% following ART (p=0.720). Negative Western blot results were observed in 89% and 12% of participants prior to and following 24 weeks of ART, respectively (p <0.001). Seroreversion to non-reactivity during ART was observed to at least one of the tests in 20% of participants, with fourth-generation immunoassay demonstrating the highest frequency (11%) of seroreversion. CONCLUSIONS
 HIV-specific antibodies may fail to develop and when detected may decline when ART is initiated during AHI. While fourth-generation immunoassay was the most sensitive at detecting AHI prior to ART, third-generation immunoassay was the most sensitive during treatment.

CLINICAL TRIALS REGISTRATION
 NCT00796146 and NCT00796263.