The response to chemotherapy of serum Mycobacterium leprae-specific antigen in multibacillary leprosy patients.

We have examined the Mycobacterium leprae phenolic glycolipid-I (PG-I) antigen levels in the sera of 45 multibacillary leprosy patients commencing chemotherapy. The PG-I antigen levels correlated with the bacterial and morphological indices, but not with the serum IgM anti-PG-I antibody levels. Antigen levels were significantly higher in patients with diffuse skin infiltration, but did not vary significantly with other parameters reflecting the duration and extent of untreated disease. The PG-I antigen levels in 27 patients examined serially decreased consistently over the first year of multidrug therapy.