Immunology and pathogenesis of tuberculosis in HIV-infected patients

Tuberculosis is a common opportunistic infection in individuals infected with the human immunodeficiency virus (HIV) worldwide. Progressive loss of CD4 T cells in HIV-infected individuals and the ensuing immunodeficiency favor progressive primary infection with Mycobacterium tuberculosis and recrudescence of latent M. tuberculosis infection. Immune mechanisms triggered by M. tuberculosis, in turn, lead to increased HIV expression and an accelerated course of HIV disease; not all mediators and mechanisms involved have been identified, however. Our current understanding of the immunology and pathogenesis of tuberculosis as it relates to individuals dually infected with HIV and M. tuberculosis is discussed, with particular attention to immune mechanisms potentially involved in accelerating the progression of HIV disease.