To the Editor.— Immunosuppression caused by drugs, infections, cancer, or other conditions is known to increase the risk of tuberculosis.1 Studies of patients with the acquired immunodeficiency syndrome (AIDS)2,3 and of the incidence of tuberculosis in young men in selected US cities4 suggest that an increased risk of overt disease among persons previously infected with the tubercle bacillus may be associated with human T-cell lymphotropic virus type III/lymphadenopathy-associated virus (HTLV-III/LAV) infection. Project SIDA is a collaborative AIDS research project in Zaire, involving the Zairian Department of Public Health, the Public Health Service, and the Institute of Tropical Medicine, Antwerp, Belgium. In March 1985, project researchers determined the prevalence of antibody to HTLV-III/LAV in 231 (84%) of the 274 inpatients of the tuberculosis sanatorium in Kinshasa, Zaire. Of the 231 study participants, 159 (69% ) had confirmed pulmonary tuberculosis (positive results of sputum examination for acid-fast bacilli). Of these