Given that anti-GD2 antibody therapy for high-risk neuroblastoma has been developed in combination with cytokines, in particular IL-2 [1,3], it is important to note that uncommon, but severe, neurotoxicity has also been reported for IL-2 therapy alone, including coma, convulsions and paralysis (≥1/1000 to <1/100 patients) [17]. The gene discussed is IL2; the disease is neuroblastoma.