IgM immunoglobulins reacting with the phenolic glycolipid-1 antigen from Mycobacterium leprae in sera of leprosy patients and their contacts.

For the first time in Brazil it was investigated the occurrence of IgM anti-PGL-1 in the sera of household contacts of leprosy patients using the ELISA methodology. The sera of the multibacillary patients showed significantly more immuno-reactivity than from the paucibacillary patients. It was observed a high subclinical infection incidence among household contacts (19.4%). The percentage of leprosy development was 5% (1/21) among the seropositive contact group. This finding suggests that serology could be useful as prognostic test, but for better definition is necessary to test a population from endemic area for long period time.