Alpha-Interferon Inhibits Spontaneous and Induced DNA Synthesis in Hairy Cell Leukemia

Abstract

The effect of alpha-interferon (α-IFN) on spontaneous or induced proliferation of isolated peripheral blood mononuclear cells from 5 hairy cell leukemia patients was studied. a-IFN inhibited the low spontaneous proliferation of B-1y7 positive hairy cells (HCs) and also the proliferation induced by tumour necrosis factor (TNF). Interleukin-2 did not affect HCs, but induced CD4 positive T cells to proliferate, an effect which α-IFN antagonized. The stimulatory effect of TNF on the growth of HCs proved to be reversible and was partially blocked with either anti-TNF receptor or anti-lymphotoxin antibodies. Cellular or secreted thymidine kinase levels reflected the proliferative state of HCs in response to different in vitro treatments, as confirmed by thymidine incorporation and cell cycle studies.

Key Words:

• Hairy cell leukemia
• Interferon
• Tumor necrosis factor
• Interleukin-2
• Thymidine incorporation
• Deoxythymidine kinase