The impact of highly active antiretroviral treatment (HAART) on anti-human immunodeficiency virus (HIV) cytotoxic T lymphocytes (CTL) was studied in 17 patients with recent symptomatic HIV-1 primary infection receiving triple combination therapy. Anti-HIV CTL were initially detected in 15 patients. In 6, CTL disappeared rapidly and persistently after initiation of therapy. Most of them had a rapid and sustained decrease in plasma HIV RNA to undetectable levels. Conversely, in 6 other patients, CTL remained detectable, which was associated with a less efficient control of viral replication. In 3 others, CTL disappeared only transiently, without clear correlation with the virologic profile. Altogether, despite individual variations, there was a positive correlation between viral replication and anti-HIV-1 cytotoxicity in most subjects, suggesting that the persistence of viral antigens is the main determinant for the maintenance of CTL activity. This raises the question of the potential benefit of anti-HIV CTL induction by immunotherapy in acute seroconverters treated by HAART.