IL2 THERAPY POST AUTOLOGOUS STEM-CELL TRANSPLANTATION STIMULATES THE PRODUCTION OF TUMOR CYTOTOXIC CYTOKINES IN CHILDREN AND ADOLESCENTS WITH SOLID TUMORS

Children with solid tumors of poor prognosis have benefitted from autologous bone marrow transplantation as a treatment modality. Adjuvant interleukin-2 (IL2) therapy has previously been shown to improve prognosis in adults with some solid tumors. In this setting improved survival probability has been attributed to IL2-mediated augmentation of antineoplastic activity of the immune system. In this study 8 pediatric patients in complete remission after autologous stem cell transplantation were treated with recombinant IL2 administered in 3 cycles of 5 days continuous intravenous infusions and a two week rest inbetween. We demonstrated that IL2 therapy increased transplantation-related activation of the immune system both on cellular and humoral levels. Peripheral blood T and NK cell number increased by the factors 1.7 and 6.0 respectively. NK and T cell activation were further enhanced as indicated by elevated levels of soluble IL2 receptor. The production of tumor cytotoxic cytokines like alphaTNF and gammaINF was stimulated. The elevated aTNF and gammaINF cytokine synthesis seemed to be mainly related to the activation and proliferation of NK cells, as T cells obtained from patients after IL2 therapy showed a definite cytokine production deficiency after T cell specific stimulation.