[Immunosuppression as a concomitant effect].

1. It is becoming increasingly clear that besides traditional immunosuppressive agents, an array of miscellaneous influences and conditions, as well as drugs used for other purposes, can affect the immune system. The potential pathogenetic role of immunity in an ever growing number of diseases, including infections, cancer, and autoimmune processes, confers on the concept of concomitant immunosuppression or immunotoxicology its due place in the discipline of immunopharmacology. 2. Microorganisms such as viruses, bacteria, and protozoa (and their products), as well as parasites, may depress immune reactivity. The mechanism of action, dose-response dependency, effect of timing, and relation to bacterial adjuvanticity need more thorough exploration. 3. The efficacy of immunosuppressive drug protocols can be improved by combining immunosuppressants without bone marrow toxicity, such as niridazole or free fatty acids, with the standard antiproliferative immunosuppressive agents. 4. Prostaglandin is a likely candidate for an essential role as an immunosuppressive effector. Its release from T-suppressor cells is triggered for example by microorganisms. Moreover, dietetic and metabolic factors, such as free fatty acids, and nervous impulses affect prostaglandin formation. If thus constitutes a link between the nervous system and, on the other hand, immunity and possibly cancer.