Increased expression of human monocyte HLA-DR antigens and Fc gamma receptors in response to human interferon in vivo.

The expression of class II MHC encoded antigens (HLA-DR) and Fc gamma receptors by peripheral blood monocytes from untreated patients with small cell carcinoma of the bronchus was compared with that of normal donors. Fc gamma receptor expression was found to be elevated in these patients in comparison with normal. In contrast HLA-DR antigen expression by patients' monocytes was somewhat depressed in comparison with normal. Continuous intravenous infusion of a total of 400 megaunits/m2 of human lymphoblastoid interferon-alpha (IFN-alpha) over a 5 day period markedly increased both monocyte HLA-DR antigen expression and Fc gamma receptor expression in comparison with that of untreated patients and normal donors. The initial increases declined somewhat but were still evident after 3 weeks of intermittent intramuscular IFN-alpha therapy.