[Dynamic study of anti-HIV antibody avidity after cellular immunity restoration under antiretroviral treatment].

We have studied the evolution of the avidity of anti-HIV antibodies, in 14 infected patients with Aids, including 11 patients with severe immunodeficiency at Aids stage and under active antiretroviral therapy (HAART), and 3 non-treated patients with moderate immunodeficiency. These patients have been followed up to 4 years, every 4 months the first year and every 6 months the three others, with HIV1 RNA viral load, CD4 and CD8 cells dosages and anti-HIV avidity measurements (Axsym HIV-1/2), using 1 M guanidine denaturation. A rapid decrease of the viral load was observed under Haart, inducing immune restoration with CD4 and CD8 cells increases (10 and 2-fold respectively). The decrease of anti-HIV avidity (- 20%) has been observed after 5 to 8 months under Haart, with a return to baseline value (84%). The quick restoration of CD4 cells with a persistence of viral antigens at the beginning of treatment has facilitated the selection of novel naive B lymphocytes producing low-affinity antibodies, measured by the decrease of global anti-HIV avidity. The reduction or even clearance of viral antigens under Haart could secondarily induce the selection of B lymphocytes with higher antibody affinity and therefore higher anti-HIV avidity. Thus, this avidity measurement could be used to assess the functional activity of CD4 cells restoration in HIV infected patients under Haart.