Induction of intracellular and plasma 2',5'-oligoadenylate synthetase by pentostatin

Similar to interferon α, pentostatin is highly effective in hairy cell leukemia and moderately active in other chronic lymphoid malignancies. In ten patients with hairy cell leukemia (HCL) and seven patients with other B-cell chronic leukemias (BCL), we have studied the intracellular 2',5'-oligoadenylate synthetase (2,50AS) activity of the mononuclear cells before, 4 h, 24 h, and 48 h after pentostatin administration. In patients with HCL the median level of intracellular 2,50AS increased 4.6-fold at 4 h and 11.5-fold at 24 h compared to the pretreatment value