Anergy in pregnancy and malignant disease: the role of the immunosuppressive alpha-globulin.

Both tumour and trophoblast produce an immunosuppressive protein which is believed to be a prostaglandin (PG) antagonist. Substances which digest this protein (protease) or enhance the synthesis of PG (levamisole) can reverse the immunodepression in cancer patients. The relevance of these observations to cancer immunotherapy is discussed.