Growth inhibitory effects of interferon on normal and malignant human haemopoietic cells

A study of the effects of human leukocyte and lymphoblastoid interferon preparation on the growth of normal, immune and malignant haemopoietic cells has been carried out. At a standard dose of 10,000 U/ml, incorporation of tritiated thymidine ([3H] TdR) was reduced by 7-92% of control values, and cell survival by 35-82% in acute myelogenous leukaemia cell cultures, whereas in normal bone-marrow cultures interferon showed a 58-62% reduction in [3H] TdR uptake but only up to 13% reduction in cell survival. [3H] TdR incorporation by MLC-stimulated lymphocytes was also significantly reduced by interferon but the blastogenic response to PHA was not. These effects of interferon were shown to be dose-dependent. The problems of using interferon in the treatment of AML in the light of these findings are discussed.