[Correlation of skin tests and the production of gamma-interferon in leprosy patients].

The responsiveness of 25 leprosy patients to an in vitro correlate of cell-mediated immunity to M. leprae antigen, (the production of Y-IFN by peripheral blood mononuclear cells) was compared to their response to skin tests routinely used to evaluate cell-mediated immunity to a number of antigens including M. leprae. The results indicate that among the polar lepromatous patients (LL) there was a clear correlation between low responses in the in vitro assay (Y-IFN production), negative skin test to the specific antigen (Mitsuda reaction) and low responses to skin tests to a related antigen (PPD). There was no correlation in the other clinical groups with skin tests to other unrelated antigens.