 The acquisition of opportunistic infections has been causally linked to innate and acquired immunodeficiencies. We have recently identified a population of Asian women with autoantibodies to interferon gamma IFN?, all of whom were diagnosed by virtue of nontuberculous mycobacterial infections. Similar patient populations have been reported from Thailand, and we have found similar autoantibodies in anonymous serum samples from there. In addition, many of the Thai patients who have disseminated or lymphatic nontuberculous infections have had other opportunistic infections OI, such as salmonella, penicilliosis, and histoplasmosis. However, they have normal lymphocyte counts and are human immunodeficiency virus HIV negative. Therefore, the identification of autoantibodies to a critical cytokine, the occurrence of opportunistic infections, and the lack of other common explanations suggests that this is an important population to study. We propose to enroll patients in a natural history study of non-HIV opportunistic infections to explore the presence of autoantibodies to cytokines, and to examine potential immunogenetic factors influencing the development of this disease. Plasma, cells, and DNA samples will be obtained and stored for use in this study. This study will accrue up to 265 patients over 5 years as per with follow up for 15 years on each patient, sample size justification and the groups described in the protocol. 