Modulating effect of interleukin 2 therapy on interferon production by blood leukocytes of patients with minimal residual hematological disease

This study was designed to investigate the effect of 1.8 x 10(6) U/day interleukin 2 (IL-2) therapy on interferon (IFN) production. Patients enrolled in the study suffered from multiple myeloma (MM), Hodgkin's disease (HD) and non-Hodgkin lymphoma (NHL). All of them were in remission after chemotherapy or radiotherapy. Results indicated that IL-2 given subcutaneously at a dose of 1.8 x 10(6) U/day for 3 weeks induced IFN-gamma in serum of patients and caused a prolonged effect on the ability of blood leukocytes to produce IFN-gamma after stimulation in vitro by mitogen phytohemagglutinin (PHA). Such enhancement of IFN-gamma production may be beneficial for antitumor immune response. Low-dose IL-2 therapy was well tolerated by all patients and side effects not exceeding II grade of toxicity according to WHO scale were observed. Five patients with MM have relapsed 3-10 months after cesation of IL-2 therapy but 15 patients 18 months after therapy were in complete remission.