IMMUNOLOGICAL AND VIROLOGICAL EVALUATION AFTER INFLUENZA VACCINATION OF HIV-1-INFECTED PATIENTS

Objective: The present study was designed to determine the effect of i mmune activation, achieved by influenza vaccination, on plasma HIV RNA levels and immunological parameters including CD4 cell levels, antige n-stimulated T-cell function and apoptotic death of peripheral blood m ononuclear cells. Design and methods: Thirty-four HIV-infected individ uals and nine uninfected controls were immunized with influenza vaccin e and blood was collected at weeks 0, 2, 4 and 16. Plasma was isolated and used for HIV RNA and influenza-specific antibody quantifications. CD4 cell counts, activation and maturation markers of T-lymphocyte su bsets were determined by flow cytometry. In vitro T-helper responses, spontaneous- and activation-induced cell death assays were also perfor med. Results: Influenza-specific humoral and cellular immune responses correlated with CD4 count. Only in patients with CD4 counts > 300 x 1 0(6)/l there was a modest increase in T-cell responses to influenza vi rus, which was less than control subjects, observed after vaccination. Immunization had no significant effect on CD4 counts or plasma viral levels in the HIV-positive patients. Baseline apoptosis inversely corr elated with CD4 counts and directly correlated with viral load. Activa tion-induced apoptosis did not change appreciably after vaccination an d spontaneous apoptosis increased only in the < 300 CD4 group. Conclus ion: These results indicate that immune stimulation resulting from inf luenza vaccination did not significantly change the levels of plasma v irus, CD4 cell counts, or activation-induced apoptosis in HIV-infected individuals, although an increase in the T-cell response to influenza and spontaneous apoptosis was observed in the > 300 and < 300 CD4 gro ups, respectively.