Demonstration of PGL I antigens in skin biopsies in indeterminate leprosy patients: comparison with serological anti PGL I levels.

The survey of histological findings in leprosy patients from 1985 to March 1988 has been carried out at the Pasteur Institute in Noumea. Histologically, according to Ridley Jopling criteria, 82 patients were classified, 14 as T.T., 12 as B.T., 2 as B.B., 7 as B.L., 4 as L.L.s., 24 as L.L.p. and 19 as Indeterminate leprosy. Histological examination of tissues sections, using a monoclonal anti-PGL I antibody showed PGL I antigen in histiocytic cells of the infiltrate and more rarely in Langerhans cells in 7 cases of indeterminate leprosy. The Ziehl staining method revealed the presence of alcoholo resistant bacilli in only one case. For 10 patients, histological findings were compared with serological results. In 3 cases, the diagnosis was confirmed by the 2 techniques (immunohistology and serology). In 2 cases by only immunohistology or by serology and in 3 cases the diagnosis was not confirmed by either methods. These results showed the interest of the immunohistological and serological methods in indeterminate leprosy, specially in children. A study of household contacts may be of interest.