Immunohistochemical study of lepromin reaction in healthy adults.

Lepromin reaction was studied with immunoperoxidase techniques using monoclonal antibodies. The skin reactions were induced by injecting Mitsuda antigen into healthy adults without a family history of leprosy. Both early (48 hours) and late (3 weeks and 2 months) reactions were examined. In the late reaction, focal collections of epithelioid cells had formed, and not only T- but also B-lymphocytes were observed around the granuloma. CD1a+ cells were also confirmed to have increased in the late reaction.