This is a phase I/II, controlled, open label, dose escalation study to determine the tolerance, toxicity, and clinical effect of the administration of interferon-gamma on the clinical condition and immune function of patients with multiply drug resistant M. tuberculosis infections (MDRTB). The study drug (interferon gamma) will be administered subcutaneously three times a week at three dose levels (0.025 mg/m(2), 0.05 mg/m(2), 0.1 mg/m(2)) for one year in addition to anti-tuberculous medications, as determined by in vitro sensitivities.