Comparison of effects of leukocyte and fibroblast interferon on immunological parameters in cancer patients.

Patients with metastatic cancer were given single intramuscular injections of 10(7) units of partially purified preparations of either leukocyte or fibroblast IFN. Serum levels of inteferon, of beta 2-microglobulin and of carcino-embryonic antigen (CEA), as well as NK activity of circulating lymphocyte, were followed over a period of 96 hr post injection. In confirmation of previous studies, levels of circulating IFN were lower after injection of fibroblast IFN than after injection of leukocyte IFN. Despite this difference in pharmacokinetics, the natural killer activity of circulating lymphocytes was enhanced with both IFNs. Levels of DEA were not influenced by the IFN injections. Leukocyte but not fibroblast IFN caused an increase in serum levels of beta 2-microglobulin in the circulation. A similar difference between leukocyte and fibroblast IFN in their ability to influence the beta 2-microglubulin system was observed in experiments on cell cultures. Only leukocyte IFN was able to cause release of beta 2-microglobulin by either leukocytes or fibroblasts.