Effect of in vivo administration of interferon on human monocyte function

We studied the function of peripheral blood monocytes in patients receiving interferon. Patients received i.m. injections of Wellferon at doses ranging from 0.75 to 50 X 10(6) U every 12 h for 7 days. Monocyte function was evaluated prior to and 7-28 days following the institution of interferon therapy. As a group, these patients showed some rise in chemokinesis, but evaluation of phagocytosis, adhesion, spreading, chemotaxis, microbial killing, and tumor cytotoxicity failed to demonstrate clear evidence of monocyte activation. About half of the patients did show a significant rise in their monocyte count, Candida killing, and chemotaxis following interferon therapy. More patients demonstrated a rise in monocyte count and chemokinesis with higher doses of interferon, but other functional assays were either unaffected or had fewer patients demonstrating activation with the higher doses. Patients whose tumors showed stabilization or partial response after interferon were more likely to exhibit a rise in monocyte count, Candida killing, spreading, and tumor killing than were patients whose disease progressed.