The expression of PNA-lectin binding sites and S-100 protein in histiocytic lesions of the skin. A comparative immunohistochemical study.

In this work the potential usefulness of antibodies to S-100 protein and the lectin Peanut Agglutinin (PNA) in the differential diagnosis of histiocytic lesions of the skin was assessed. Out of 54 deparaffinized specimens studied through an avidin-biotin-alkaline phosphatase technique, 35 proved to comprise S-100 (+) and 12 PNA (+) cells. The results show that antibodies to S-100 protein are useful in distinguishing the "X" (Langerhans' cell) from the "non-X"types of histiocytosis, and cast some shadow on the usefulness of the lectin PNA as a histiocytic marker. (Received May 5, 1987.)