Interferon Gamma for Drug Resistant Tuberculosis

This study will determine what dose of recombinant interferon-gamma is safe and effective for treating multiple drug-resistant tuberculosis. Recombinant interferon-gamma is a genetically engineered form of a substance normally produced by the body and is used to boost immune function.

Patients 5 years of age and older with multiply drug-resistant tuberculosis may be eligible for this study.

Participants will be admitted to either the NIH Clinical Center in Bethesda, Maryland, the Texas Center for Infectious Diseases in San Antonio or the South Texas Hospital or Valley Baptist Hospital, both in Harlingen, Texas. On admission, patients will have a medical history, physical examination, blood and urine tests, sputum culture, X-rays, pulmonary function tests and a computed tomography (CT) scan. CT produces 3-dimensional images of body tissues and organs in small sections. For the procedure, the patient lies still on a table surrounded by the scanner.

All patients will continue treatment with anti-tuberculosis antibiotics during and after the study period and may elect whether or not to take gamma interferon in addition to the antibiotic. Five patients will receive only antibiotic treatment, and 5 each will receive one of 3 doses (0.025, 0.05 or 0.1 milligrams per square meter of body surface area) of interferon-gamma injected under the skin 3 times a week. The patient or caregiver will be taught to give the injections, which are similar to insulin injections for diabetes.

Patients will be in isolation in the hospital from the start of therapy until sputum samples show no evidence of tuberculosis for 3 consecutive weeks. Following that, they will repeat the tests done on admission (except CT) during follow-up visits (1- to 2-day hospitalizations) at 3, 6, 9, 12, 15, 18 and 24 months after the start of therapy. Patients taking interferon gamma will have blood drawn more frequently (monthly) for the first 6 months, and patients with lung infection will have sputum samples collected more frequently-weekly for the first 3 months or until three consecutive negative samples are obtained and then monthly throughout the course of therapy. Patients with lung infection will also have repeat CT scans at 6 and 12 months while on interferon gamma. In one or two patients on the drug, blood will be drawn frequently following one injection of gamma interferon (just before the injection and again at 0.25, 0.5, 1, 6, 12, 18, 24 and 48 hours after it) to see if a difference in blood levels of the drug can be detected.