Immunobiology of histiocytosis-X.

On the possibility that histiocytosis-X has an immunologic basis, two major avenues of investigation have been pursued. These are studies of the immunologic and immuno-histochemical characteristics of the Langerhans cells found in the pathologic tissue of patients with histiocytosis-X and immunologic testing of such patients. Our understanding of the immunobiology of histiocytosis-X is derived from the results of these studies and current concepts of the mononuclear phagocytic system. These form the basis of this discussion.