IL2 THERAPY POST AUTOLOGOUS STEM-CELL TRA NSPLANTATION STIMULATES THEPRODUCTION OF TUMOR CYTOTOXIC CYTOKINES IN CHILDREN AND ADOLESCENTS WITH SOLID TUMORS

Children with solid tumors of poor prognosis have benefitted from auto logous bone marrow transplantation as a treatment modality. Adjuvant i nterleukin-2 (IL2) therapy has previously been shown to improve progno sis in adults with some solid tumors. In this setting improved surviva l probability has been attributed to IL2-mediated augmentation of anti neoplastic activity of the immune system. In this study 8 pediatric pa tients in complete remission after autologous stem cell transplantatio n were treated with recombinant IL2 administered in 3 cycles of 5 days continuous intravenous infusions and a two week rest inbetween. We de monstrated that IL2 therapy increased transplantation-related activati on of the immune system both on cellular and humoral levels. Periphera l blood T and NK cell number increased by the factors 1.7 and 6.0 resp ectively. NK and T cell activation were further enhanced as indicated by elevated levels of soluble IL2 receptor. The production of tumor cy totoxic cytokines like alphaTNF and gammaINF was stimulated. The eleva ted aTNF and gammaINF cytokine synthesis seemed to be mainly related t o the activation and proliferation of NK cells, as T cells obtained fr om patients after IL2 therapy showed a definite cytokine production de ficiency after T cell specific stimulation.