Interleukin 2 in Neuroblastoma

Neuroblastoma is one of the most common solid tumors in childhood, with some unusual neoplastic behavior depending on the age of the affected children. Patients older than 1 year who have metastatic disease have a very poor prognosis. However, in children younger than 1 year who have disseminated disease, regression of neuroblastoma often occurs after only minimal therapy, or even spontaneously. This latter feature and other observations led to longstanding speculations that cytotoxic effector cells of the tumor-bearing host may contribute to this biological behavior of human neuroblastoma [1]. Recently, Main et al. [2] published data concerning the interaction of human neuroblastoma cell lines with effector cells. They demonstrated that the neuroblastoma cell lines CHP 100 and CHP 126 were lysed by natural killer (NK) cells but not by cytotoxic T -lymphocytes [2]. This was interpreted as a consequence of the weak expression of HLA class-I antigens on neuroblastoma cells [3]. In this study we examined whether other neuroblastoma cell lines are susceptible targets for effector cells from healthy individuals and from patients with neuroblastoma. Since Interleukin 2 (IL-2) has considerable stimulating activity on the cytotoxic functions of lymphocytes, we further investi-