Background:  Data conflict concerning the effects on HIV-1 infection of transient increases of plasma viral load (PVL) (“blips”). It has been proposed that patients with blips could risk poorer outcome. Some retrospective studies suggest an association of blips with an increase in HIV-specific immune responses, which might help to improve the viral control after HAART interruption. The objective of the present study is to address prospectively in a cohort of treated patients the influence of blips on viral rebound after HAART discontinuation.

Methods:  We studied blips in 26 patients included in a single-center prospective, randomized, double blind, placebo-controlled clinical trial to evaluate the effect of a vaccination program on PVL in successfully treated HIV-infected adults. We did not observe that vaccinated patients had a higher proportion of blips than control patients. Patients were on HAART as long as 2 months after the last immunization and HAART was discontinued afterward (month 12) for at least 6 months (month 18). Blood samples were taken every month from 0 to 18. VL and CD4⁺ T cells were analyzed. We compared PVL rebounds in the group of patients who had blips with the group where blips were not detected.

Results:  We found transient elevation of viral load >200 copies/mL in 9 of 26 patients and in 21 of 312 viral load determinations. The blips group had a higher PVL rebound (area under the curve of 2.22 vs 1.61, p = 0.009; peak viral load 5,28 vs 4,67 log, p = 0.018) than the no-blips group. The drop in percentage of CD4 T cells after HAART discontinuation was similar in both groups (11% vs 13%, blips vs no-blips, respectively, p = 0.55). However, the blips group had significantly lower CD4⁺ T-cell counts at study entry (month 0) (34 vs 41% ; blips vs no-blips group, respectively, p = 0.04). On the other hand, differences in PVL rebound and drop in CD4⁺ T cells after HAART interruption between vaccinated and not vaccinated were not observed.

Conclusions:  Early stage HAART-treated patients with blips controlled viral replication after interruption of treatment more poorly, although it did not influence the drop in CD4⁺ T cells after 6 months off HAART. Repeated immunological stimuli with commercial vaccines (a total of 195 stimuli in 13 patients) do not influence in the rebound after stopping HAART.