On the potential role of cyclosporin in the treatment of lymphoproliferative diseases.

Lymphomas and leukemias, as cancers of the immune system, may still retain some susceptibility to regulatory mechanisms which govern the proliferation of their cells of origin. According to this concept, an enhanced immune suppression as induced by irradiation and chemotherapy may contribute to their cytotoxic effect in inducing and maintaining a remission of the disease. Cyclosporin selectively and reversibly inhibits activation and proliferation of both normal and neoplastic T lymphocytes. In-vitro experiments and preliminary clinical data from small uncontrolled studies indicate that cyclosporin might be a promising agent in the treatment of mycosis fungoides, Hodgkin's disease, acute leukemia, and possibly other lymphoproliferative disorders, but the experience is still limited and no definitive conclusions may be made. In addition to its direct effect on lymphocytes, cyclosporin reverses the resistance of cancer cells to several antineoplastic agents and may thus find its place in combination with chemotherapy. It is hoped that a more systematic basic and clinical research will help define the role of this new therapeutic approach.