The effects of gamma interferon on the natural killer and tumor cells of children with neuroblastoma. A preliminary report

Human neuroblastoma cells lack HLA‐A,‐B,‐C molecules which can be induced in vitro by gamma interferon (γIFN). To test the hypothesis that the same induction would occur in vivo leading to tumor regression, a Phase I study was initiated. Seven patients with neuroblastoma were entered on a Phase I study of recombinant γIFN in children. Three received 0.05 mg/m² intravenously (IV) three times a week, three received 0.1 mg/m² for 4 weeks, and one patient withdrew from study before receiving adequate treatment for evaluation. No significant clinical response was seen. The side effects were fever and chills, and no serious toxicity occurred. Natural killer (NK) and lymphocyte activated killer (LAK) precursor activity of peripheral blood mononuclear cells was determined before and during treatment, and expression of HLA‐A,B,C molecules was looked for on the tumor cells in the bone marrow of five patients. The NK activity initially low, reached control levels in six patients, but the increase was transient. The LAK precursor activity remained normal. Expression of HLA‐A,B,C, initially absent, was induced on the neuroblastoma cells in four of six patients.