[Effectiveness of gamma interferon and alpha interferon in hairy cell leukemia]

Six patients with hairy-cell leukemia were treated with gamma-(IFN-gamma) and alpha-(IFN-alpha-2b) interferon; 3-35 months following splenectomy, treatment was started with 4 X 10(6) U/m2 IFN-gamma sc (iv) every second day for 9-35 weeks. Although the white blood cell counts decreased during therapy from 4.1-49 X 10(9)/l to 1.5-43 X 10(9)/l, no hematological or clinical improvement was obtained. Subsequently (interval 0-13 weeks), IFN-alpha-2b was given at an initial dose of 4 X 10(6) U/m2 sc every second day to all patients. After a treatment period corresponding to that of IFN-gamma administration, a significant hematological improvement was observed in five patients (one early death due to pulmonary embolism). At the last follow-up (9-14 months after start of treatment; maintenance therapy, 1 X 10(6) U every second day), these patients exhibited normal peripheral blood cell counts, and in bone marrow biopsy specimens a marked decrease of hairy cells was seen (1 CR, 3 PR, 1 MR). Adverse reactions including fever, headache, nausea, dryness of the mouth, myalgia, and fatigue did not significantly differ between the two interferon preparations. Whereas IFN-gamma is unlikely to have any significant impact on the course of hairy cell leukemia, IFN-alpha-2b does result in improvement of hematological values and well-being in almost all patients.