Immunohistochemical study of idiopathic histiocytosis of the mandible and maxilla.

Recent evidence suggests that the proliferative cells of idiopathic histiocytosis may be derived from Langerhans cells. In this study, antisera to S-100 protein, HLA-DR (la-like) antigen, muramidase, and alpha 1-antichymotrypsin were tested on formalin-fixed, paraffin-embedded tissue from nine cases of idiopathic histiocytosis using an immunoperoxidase technique. Tumor cells were positive for S-100 protein and HLA-DR antigen but negative for muramidase and alpha 1-antichymotrypsin. Mononuclear phagocytes were positive for HLA-DR antigen, muramidase, and alpha 1-antichymotrypsin but negative for S-100 protein. The immunohistochemical staining pattern of the tumor cells in these cases of idiopathic histiocytosis is similar to that seen for normal Langerhans cells. When these results are coupled with electron microscopic and histochemical data, it would appear that the origin of cells in idiopathic histiocytosis is from the Langerhans cell or its precursor. Thus, this condition might be better designated "Langerhans cell disease."