Antitumor activity of CD7^KOCD7 CAR T cells against primary T-ALL blasts. (A) Surface expression of CD7 in peripheral blasts in 4 T-ALL patient samples. (B) Representative dot plots showing production of TNFα and IFNγ by CD7 CAR T cells on coculture with allogeneic primary T-ALL blasts. (C) Mean frequencies of cytokine-positive CD7^KO CD7 CAR T cells on coculture with individual T-ALL samples. (D) Peripheral blasts were freshly isolated from a T-ALL patient by leukapheresis, labeled with eFluor670 and cocultured with control or CD7^KO CD7 CAR T cells for 48 hours. Dot plots show the frequency of live tumor cells at the end of coculture. (E) Absolute counts of live tumor cells and CD7^KO CD7 CAR T cells quantified by flow cytometry at the end of coculture. Data represent 1 to 2 independent with n = 3 donors in each. *P < .05; **P < .01.