Better preserved immune responses after immunization with rgp 160 in HIV-1 infected patients treated with highly active antiretroviral therapy than in untreated patients with similar CD4 levels during at 2 years' follow-up.

To study the impact of effective highly active antiretroviral therapy (HAART) on the preservation of long-term CD4 memory cells induced by vaccines in HIV-1-infected patients. Thirty HIV-1-positive patients on HAART with undetectable viral load were randomized into three groups: 10 received HIV-1 rgp160 vaccine, 10 received tetanus vaccine and 10 patients were not immunized. As controls, 10 HIV-negative volunteers were immunized with tetanus vaccine. The results were compared with an rgp160 vaccine study performed before the era of HAART on patients with comparable CD4 levels. All patients were monitored for 2 years for T-cell proliferative responses, T-cell subset levels, serum IgG and viral load. After 1 year all patients immunized with rgp160 had strong T-cell responses to the rgp160 antigen. After 2 years this response was preserved in the HAART-treated group, but not in the rgp160 immunized non-HAART group, despite comparable CD4 levels. Recall effects of the CD4-specific responses towards other antigens were seen in the rgp160-immunized HAART group. Immunization with rpg 160 leads to positive effects on HIV-specific T-cell proliferative responses in patients both with and without HAART. Immune responses after immunization is better preserved in HAART-treated patients who have low viral amounts than in individuals with high viral load and no HAART despite comparable CD4 levels during 2 years' follow-up. Interruption of HAART with return of a high viral load might thus have negative effects on T-cell functions in the long term, even if CD4 levels are kept at clinically acceptable levels.