HIV-infected patients with active TB follow an anti-TB regimen including rifabutin and are observed for a maximum of 24 weeks before they initiate HAART. Plasma samples for 24-hour post-rifabutin dosing are collected at entry and at Weeks 4, 8, and 12, then again at Weeks 2, 3, 4, 12, and 24 after HAART initiation. Analyses of these samples are used to explore the relationship between cytokines and rifabutin metabolism and the effect of nelfinavir on rifabutin pharmacokinetics. The HAART regimen is nelfinavir plus lamivudine (3TC) plus either zidovudine (ZDV) or stavudine (d4T). After initiation of HAART, all patients undergo intensive monitoring of viral and immune dynamics for 2 months. The patients continue to be followed for 1 year from the time of starting HAART. Neither the HAART drug regimen nor anti-TB medications will be provided by the study and must be obtained by prescription. If patients are intolerant of the HAART regimen or exhibit virologic rebound, primary providers can alter or modify this regimen. As part of substudy A5065s, patients who experience signs or symptoms of paradoxical reactions (i.e., new persistent fevers that develop after initiating HAART and which last for more than 1 week without an identifiable source; marked worsening or emergence of intrathoracic lymphadenopathy, pulmonary infiltrates; worsening or emergence of cervical adenopathy on serial physical examinations; or worsening of other tuberculous lesions) have additional clinical evaluations (including a chest x-ray, a target clinical assessment, concomitant medications, and signs and symptoms) weekly for 4 weeks, then every month thereafter until the symptoms resolve.