We will maintain a clinical core to provide specimens from patients with mycobacterial infection and from appropriate controls for the experimental protocols outlined in the research projects. The core will be located at the Washington University AIDS Clinical Trials Unit (ACTU) which is a component unit of part of the NIAID-supported AIDS Clinical Trials Group (ACTG). Currently, approximately 400 patients are followed at the unit on a regular basis and approximately 20 new patients are referred each month about half of whom are enrolled on studies on antiretroviral therapy or of new agents for the treatment of AIDS-associated opportunistic infections of malignancies. In addition the Division of Infectious Diseases provide primary HIV core for 600 HIV infected patients (250 of whom are women) which can act as an additional source of patient material. This patient population will serve as the source of clinical material. All HIV+ patients are staged clinically and by measured of the CD4 lymphocyte count and HIV plasma RNA. A confidential registry is maintained using a specific identifying number as the sole identifier. This registry comprises basic demographic data as well as the HIV-specific staging data. In addition, baseline serum samples are obtained on all patients at the time of initial visit to the ACTU and stored at (-70 degrees Celsius) for possible future testing. The clinical core will contribute to the program project in two ways: (i) Samples of serum, plasma and cells from patients infected with mycobacterial infections, at risk for mycobacterial infections, and relevant control patients with HIV infection and AIDS will be collected; (ii) the confidential patient database will be maintained to allow program investigators to obtain clinical and other laboratory correlates when needed. This should allow investigators to correlate results with the stage of HIV infection and to carefully match controls for stage of disease, competing illnesses and therapy.