In the clinical study presented here, high responders experienced a median production of anti-3S Abs over 180 U/mL at week 48, a titre close to that observed in the 3S-vaccinated macaques (about 200 U/mL) together with a substantial increase in CD4 counts,20 whereas persistent low CD4 counts have been associated with non-AIDS related events.11 This evidence concerns the gene CD4 and AIDS.