Immunotherapy with Mycobacterium vaccae and the treatment of tuberculosis.

In this study, 206 previously untreated patients with sputum culture positive pulmonary tuberculosis were randomized to receive an injection of killed Mycobacterium vaccae as immunotherapy, or of saline as placebo, after 1 month of a 6-month chemotherapeutic regime. Not surprisingly in a disease for which there is good chemotherapy, the difference in numbers which were culture negative at the end of treatment was small, and the final outcome at the latest post-treatment follow-up did not reach statistical significance between the two arms of the study. Nonetheless, those receiving immunotherapy showed better progression in every parameter measured, suggesting faster and more complete cure. Whereas seven of 97 patients receiving immunotherapy required a course of re-treatment and five still had active disease after a mean follow-up of 2 yr, 13 of 109 placebo recipients required re-treatment and nine still had active disease at the end of the study. Only one patient receiving M. vaccae plus chemotherapy died of tuberculosis, compared with four of those receiving chemotherapy alone. A degree of drug resistance was shown by the bacilli cultured from 25 of 175 (14%) patients, and seven of them (4.0%) were multi-drug resistant. Fourteen patients received immunotherapy of whom 13 were cured, including all three of those showing multi-drug resistance. Of the 11 patients with drug resistance in the control group, eight were cured, and one patient with multi-drug-resistant disease died of tuberculosis during re-treatment.