Anti-arabinogalactan IgM/IgG ratio: a screening index for leprosy patients

The serological activities of arabinogalactan from M. smegmatis and phenolic glycolipid-1 from M. leprae were examined by Enzyme Linked Immunosorbent Assay using sera from 88 patients with leprosy (44 treated and 44 untreated) and 45 normal healthy individuals. Both IgM and IgG type of antibodies were measured against these antigens. The results confirmed the previous observation that anti phenolic-glycolipid-1 IgM antibodies are higher in lepromatous leprosy cases than in normal individuals. However, with arabinogalactan, the ratio of IgM/IgG was more than one in normal individuals and less than one in untreated LL patients. Treated patients fell in both categories. Moreover, a reverse relationship was found between anti PGL-1 IgM titers and anti arabinogalactan IgM/IgG ratio.