Effects on immune system and viral reservoir of a short-cycle antiretroviral therapy in virologically suppressed HIV-positive patients.

Background: Atripla dose reduction decreases subclinical toxicity and maintains viral suppression in HIV+ individuals but the virological efficacy and immunological safety of this strategy needs to be further confirmed.

Methods: Virologically suppressed HIV-infected adults on Atripla once-daily were randomized 1 : 1 to reduce therapy to 3 days a week (3W, n = 30) or to maintain it unchanged (once-daily, n = 31). HIV-1 reservoir (total and integrated HIV-1 DNA in CD4 cells) and immunological cell activation (CD38 and HLA-DR), senescence (CD57 and CD28), apoptosis (annexinV) as well as T-naive, effector memory (TEM) (CCR7, CD45RA) and stem cell memory (TSCM) (CD954 and CD27) populations were measured at baseline, 24 and 48 weeks.

Results: No differences on activation, senescence or apoptosis of both CD4 and CD8 T cells were observed on follow-up. Nave CD4 T-cell proportion showed a significant decrease in the 3W group (mean ± SD): 24.6 ± 13.7 vs. 20.5 ± 12.9 (P = 0.002). No differences in both plasma viral load and HIV reservoir were detected on follow-up. CD4 TSCM levels at 48 weeks correlated with basal integrated HIV-1 DNA in the 3W group but not in the once-daily group. A post hoc analysis of data prior to the study entry revealed a higher viral load zenith and a trend to lower CD4 nadir in 3W vs. once-daily group.

Conclusion: No significant immunological or viral changes were induced in the 3W group confirming the virological efficacy and immunogical safety of this strategy. In-depth virological and immunological analyses are useful in providing additional information in antiretroviral switching studies (Clinical Trials.gov: NCT01778413).