THE DETECTION OF Mycobacterium tuberculosis BY PCR IN SPUTUM SAMPLES FROM LONG-TERMTREATED LEPROSY PATIENTS: ASSOCIATIONS WITH SKIN TEST RESULTS AND IMMUNOTHERAPY WITH Mycobacterium vaccae

As part of a series of investigations at Baba Baghi Leprosarium in lran, 44 long-treated leprosy patients were selected for our study. Samples of early morning sputum were obtained from each patient, examined by microscopy for acid-fast bacilli (AFB), and cultured for tubercle bacilli. These tests were negative, but the polymerase chain reaction (PCR) for an insertion sequence believed to be specific for Mycobacterium tuberculosis was applied to each sputum sample and those from six patients were found to be positive. Five of the six positive samples were from the 21 patients producing Koch-type responses to tuberculin, and none were from the 11 patients previously found to have skin-tissue fluid or sputum positive by PCR for Mycobacterium leprae. Whereas immunotherapy with killed Mycobacterium vaccae given nearly 2 years earlier to 23 of the patients strongly influenced PCR results for M. leprae (p= 0.0 I), it had no influence on results fm' tubercle bacilli. However, at a second sampling date 18 months later, the only 2 patients still positive by PCR for tubercle bacilli came from the placebo recipient group. The possible significance of the findings is discussed.