Biochemical and immunological responses of hairy cell leukemia patients to interferonβ

Abstract

Ten hairy-cell leukemia patients were treated with interferon β (IFN-β) at a dose rate of 2 × 10⁶ IU/m² × 5 days for 4 weeks (induction therapy) and, thereafter, at the same dose three times a week for 11 months (maintenance therapy). The effect of this treatment on serum neopterin, β2-microglobulin, (2′–5′)oligoadenylate [(2′–5′)A _n ] levels, intracellular (2′–5′)A _n values and human Mx protein synthesis was analysed. There were significant rises in serum neopterin and (2′–5′)A _n levels during both induction and maintenance, whereas β2-microglobulin levels rose only during induction. Rises in intracellular (2′–5′)A _n were documented mainly during induction, but they were not significantly higher than pretherapy values. IFNβ provoked an increase in human Mx protein synthesis over the entire induction — maintenance period, but was only significantly higher than baseline during induction. All markers proved useful for monitoring the effects of IFNβ dose schedules, but were not predictive of clinical outcome. Natural killer activity and IFNγ production, which were initially defective, followed a different trend from that of the other factors studied, in that increases were documented only late in the course of therapy when the disease was already in remission.