Immunofluorescence studies across the leprosy spectrum.

Forty biopsies from skin lesions of untreated (24) and treated (16) leprosy patients, representing the whole leprosy spectrum, were examined by means of immunofluorescence (IF) methods. Only few or no cells staining with FTC-labelled antihuman immunoglobulin antisera were found in the lesional skin of all patients examined. Sparse IgM-deposits along the basement membrane of the epidermis were observed in a few borderline lepromatous and lepromatous patients. Complement deposits along the basement membrane of the epidermis and in the vessel walls were found in tuberculoïd as well as in lepromatous patients. Complement and in a lesser number IgG-deposits were observed around sweat glands and sometimes around sweat gland ducts and other skin appendages. Autofluorescing macrophages were noted in patients at the lepromatous side of the leprosy spectrum; approximately half of these patients showed complement deposits in an around these cells.