Effect of ART on CD4⁺ T-cell counts, HIV RNA, and specific antibody titers in primary and chronic HIV infection. Twenty-six individuals with PHI were sampled at baseline and after 6 months of ART, while 19 with CHI were sampled at baseline and 4 more times over a 24-month period of ART. (A) Changes in CD4⁺ T-cell counts and HIV RNA in subjects with PHI at baseline and after 6 months of therapy. (B) Changes in CD4⁺ T-cell counts and HIV RNA in subjects with CHI. (C) Antimeasles and anti-gp41 antibody titers in subjects with PHI at baseline and after 6 months of therapy. (D) Antimeasles and anti-gp41 antibody titers in subjects with CHI.