The intent of this study is to define more precisely the natural history and immunopathogenesis of MAC disease in the HIV-infected population. It is suggested that MAC disease in AIDS patients results both from specific immunologic deficiencies caused by HIV infection of the host and as a result of specific mycobacterial virulence properties. Therefore, aggressive antiretroviral drug treatment of HIV-infected patients at risk for DMAC due to specific immune deficiencies will improve these immune functions in such a manner as to resist DMAC.