Objectives: To study the impact of highly active antiretroviral therapy (HAART) on isotype switching and avidity maturation of HIV-1-specific immunoglobulin G (IgG) in patients with primary HIV-1 infection (PHI).
Methods: We studied the emergence and the evolution of anti-HIV IgG antibodies by quantitative immunoblotting to analyse IgG subclasses and IgG avidity. Serum samples were obtained from 16 PHI patients from the French PRIMO Cohort Study at various points in the first year of infection: eight patients received no treatment (group I), and eight patients received efficient HAART (group II) during the study period.
Results: Early initiation of HAART in PHI patients partially prevented an increase in anti-HIV-1 IgG levels. Within IgG subclasses, the amount of anti-HIV-1 IgG1 gradually increased with time in both groups, although levels remained lower in treated patients. The anti-p24 IgG2 level was always lower in group II. We observed a decrease in anti-p24 IgG3 over time in both groups. Treatment did not affect the maturation of HIV-1 IgG avidity, which increased in both groups until month 3 and then remained high until the end of the 12-month follow-up period.
Conclusions: HAART in PHI partially prevents the emergence of HIV-1 IgG antibodies, but does not affect the quality of these antibodies, as reflected in their isotype and avidity.