IL2 and neoplasm: Upon recognition of the target tumor antigen, T cell activation and expansion can result in CRS characterized by markedly elevated soluble IL2, IL6, IL10, and IFN‐γ. In this study, TNB‐383B induced dose‐dependent CTL degranulation with no T cell expansion, a mild increase (<100‐fold) of CRS‐associated cytokines (IL‐2, TNF‐α) and no increased IL‐6 production in BM aspirate culture supernatants.