Influence of low dose rIL-2 treatment on endogenous cytokine production, expression of surface IL-2R and the level of soluble IL-2R in patients with minimal residual disease

This study was designed to investigate the immunomodulatory effect of low-dose IL-2 therapy (100 mu g/day for 3 weeks) on interferon (IFN), tumor necrosis factor (TNF) production in vivo and in vitro and on the expression of IL-2R alpha/beta and soluble form of IL-2R alpha. Patients enrolled in the study suffered from multiple myeloma (MM), Hodgkin's disease (HD) and non-Hodgkin's lymphoma (NHL) All of them were in remission after chemotherapy or radiotherapy. Our results indicated that IL-2 given subcutanously at a low dose of 100 mu g/day for 3 weeks induced IFN-gamma and TNF-alpha in plasma (measured 24 hrs after the last dose of IL-2) and affected the ability of blood leukocytes to produce cytokines. Production of IFN-gamma, induced in vitro with PHA was enhanced, but TNF-alpha production induced by Lipopolysaccharide (LPS) and virus (Newcastle Disease Virus) was depressed. The expression of both: surface IL-2R, especially beta subunit on total population of lymphocytes and NK cells, and soluble form of IL-2R, alpha chain were significantly enhanced after low-dose IL-2 therapy. 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 relapsed 3-10 month after cessation of IL-2 therapy, but all patients with Hodgkin's and non-Hodgkin's lymphomas are still in remission (20 months of observation).