Histopathological monitoring of an immunotherapeutic trial with Mycobacterium w.

Immunotherapeutic trials with Mycobacterium w (M. w.) on multibacillary patients are in progress at two large hospitals in New Delhi. A total of 380 patients so far have been inducted into the trial. The histopathological profile of the initial 87 patients (52 in the vaccine group, 35 in the control group) who have now completed 2 years of treatment are presented in this report. The vaccine group received multidrug therapy (MDT) and eight intradermal injections of M. w. every 3 months; the control group had MDT with starch injections as a placebo. Skin biopsies were taken at induction and thereafter at every 6 months. The results show a significantly higher proportion of biopsies with histopathological upgrading and/or clearance of dermal granuloma among the vaccinated cases. The number of patients becoming bacteriologically negative was higher in the vaccine group. There was no increase in the degree of neural inflammation in the biopsies showing upgrading. The lepromin site biopsy in patients who converted to positivity after vaccination showed epithelioid cell granulomas as did the biopsies from the nodules developing at the vaccination sites. The histopathological observations confirm the additional immunotherapeutic effect of M. w. used along with standard MDT therapy.