Nine children with poor prognosis
neuroblastoma have been treated by continuous infusion of
IL-2 and autologous LAK cells, as described previously by West et al. in adult patients. Six patients were in relapse after high-dose
chemotherapy and autologous BMT and three presented with primary refractory disease after conventional
therapy. Although patients were very young (median age 6 years; average weight 17 kg), infusion of
IL-2, cytapheresis and reinjection of LAK cells appeared feasible with the usual and transient complications observed with
IL-2. Haematological toxicity, although reversible, was more important than usually described and due to the presence of bone-marrow
metastases in 8 of the 9 patients. Life-threatening toxicity was observed in only one of the admission centres and was probably due to the rapid reinjection of a very large number of activated cells. Two patients presenting with very active disease after high-dose
chemotherapy and autologous or allogeneic BMT received
IL-2 alone, at 120 days and at 90 days after the graft. The reactivation of grade-II GVHD was the major complication in the patient treated after an allograft, whereas no BMT-related toxicity was observed in the patient treated after the autologous BMT. Immunological modifications induced by
IL-2 were very different between these patients. As expected, a preferential outgrowth of NK cells with both NK and LAK activity was observed in the patient treated just after the autograft. In contrast, in the patient treated after an allograft and in the 9 patients in relapse, T lymphocytes remained the major mononuclear cell population with a very large excess of CD8+ T cells. All patients progressed after the first induction cycle with the exception of the only patient treated after autologous BMT who reached a very good partial remission with disappearance of the local
tumor and bone
metastases. Although very preliminary, these data clearly show that the efficacy of
IL-2 largely depends on the patient's immunological status with the optimal effect being observed when
IL-2 is given in the first few months following an autograft.