The aim of the study was to follow prospectively the humoral, cellular and innate immune responses under HAART and to verify if a functional restoration of the B lymphocytes could be evaluated by measuring the anti-HIV-1 IgG antibodies avidity index (AI). Eleven HIV-1 infected and immunosuppressed patients were included in the study. Viral load, naive and memory B-cells, CD4 and CD8 T-cells and NK-cells counts, and anti-HIV-1 IgG AI were determined during the follow-up (18 months). Ten patients were sustained responders under HAART and showed a quantitative restoration of the CD4 T-cell counts (+269 x 10(6)/L). The AI decreased for ten subjects (-11%, p = 0.006) but very slowly and continuously. A quantitative restoration of the humoral immune response began, mainly concerning the naive B-cells (+110 x 10(6)/L). Apart from one patient, the CD8 T-cell subset approached the reference values of healthy subjects either by decreasing or increasing their cell levels. No homogeneous evolution was described concerning the NK-cell subset, apart from trend towards increasing in patients with opportunistic infection (range, +58 to +291 x 10(6)/L). Our study, which evaluated simultaneously for the first time to our knowledge the cellular, humoral and innate immune responses showed that HAART induced a large diversity of immune restoration patterns in responder patients. However, the AI measure appears to be a weak marker to evaluate an immune restoration in chronic HIV-1 infected patients under HAART.