FOLR2 and acute myeloid leukemia: Subsequent analysis of the assays showed release of proinflammatory cytokines IFN-γ, IL-2, tumour necrosis factor α and inflammatory protein 1 α.11 ELISA analysis was then used to demonstrate the same reactivity by overnight incubation of m909 CAR T cells and control CD19-28Z T cells with FRβ positive AML lines, with the former incubation producing a greater secretion of IFN-γ than the latter.