Strong human immunodeficiency virus (HIV)-specific CD4(+) T cell responsesin a cohort of chronically infected patients are associated with interruptions in anti-HIV chemotherapy

Virus-specific CD4(+) T-helper cell function is important in controlling hu man immunodeficiency virus (HIV) infection but is impaired in patients with progressive HIV disease. It has been reported that after highly active ant iretroviral therapy (HAART), HIV-specific lymphoproliferative responses rem ain absent, whereas responses to non-HIV microbial antigens are restored. H owever, in analyzing immune responses in a cohort of chronically infected a dults on HAART, we observed strong HIV-specific CD4(+) T cell responses of Th-1 phenotype in 11 of 22 patients. The magnitude and frequency of HIV-spe cific lymphoproliferative responses was strongly associated with previous i nterruptions in HAART (P = .001). In contrast, the magnitude of CD8(+) T ce ll responses to HIV Gag, Pol, Env, and Nef was similar in patients who had and those who had not interrupted HAART. We conclude that (1) a significant proportion of chronically HIV-infected patients on HAART can generate stro ng HIV-specific CD4(+) and CD8(+) T cell immunity and (2) transient interru ptions in antiviral treatment may prime or boost HIV-specific CD4(+) T-help er responses.