Effect of potent antiretroviral therapy on immune responses to Mycobacterium avium in human immunodeficiency virus-infected subjects

To characterize the influence of highly active antiretroviral therapy (HAART) on cell-mediated immunity (CMI) to Mycobacterium avium complex (MAC), we measured immune responses to M. avium in human immunodeficiency virus (HIV)-infected individuals before and during HAART, in subjects with a history of disseminated MAC (DMAC), and in HIV-uninfected control subjects. Forty-seven percent of untreated HIV-infected patients and 78% of control subjects exhibited in vitro proliferative responses to M, avium (P = ,03), Proliferative responses to M. avium increased after HAART for 3 months and were present in 77% of subjects after 6 months. Mean interferon-gamma production increased from 199 to 1156 pg/mL, after HAART (P = .06). Proliferative responses to M, avium occurred in 76% of DMAC subjects receiving HAART. CD4 and CD8 but not gamma delta T cells expanded in response to M. avium. CMI to M, avium reconstitutes rapidly after HAART and appears sustained even with partial viral suppression.