Clinical and serological studies of tuberculosis patients in Argentina receiving immunotherapy with Mycobacterium vaccae (SRL 172)

Two small. placebo-controlled studies of immunotherapy with heat killed Myc obacterium vaccae added to routine chemotherapy for pulmonary tuberculosis, together involving 40 HIV seronegative patients, were carried out in Argen tina. The immunotherapy was associated with reduced sputum smear positivity of AFB at 1 month and a greater reduction in ESR at 2 months. In the first study radiological improvement was better (P < 0.05) among immunotherapy r ecipients. In the second study, weight regain and time to become apyrexial were measured and were found to be improved amongst immunotherapy recipient s (P < 0.05). In the first month of treatment the levels of IgG to the 65 kDa and 70 kDa heat-shock proteins showed greater falls following immunotherapy (P < 0.05 and P < 0.001, respectively). On admission serum cytokine levels of interle ukins 4 and 10 (IL-4, IL-10), interferon gamma (IFN-gamma) and tumour necro sis factor alpha (TNF-alpha) were grossly raised in comparison with a match ed control group (P < 0.001). After 1 month. Levels of IL-4, IL-10 and TNF- alpha fell (P < 0.001, P < 0.01 and P < 0.01, respectively) and levels of I FN-gamma rose more (P = 0.005) in immunotherapy recipients than in those re ceiving chemotherapy alone. The results are in accord with a switch towards a TH1 immunological status and clinical benefit for immunotherapy recipien ts. (C) 1999 Harcourt Publishers Ltd.