CD28 and acute myeloid leukemia: Accordingly, NKp30-CD28 CAR TCRKO T cells released IFN-γ following co-incubation with several primary AML samples (Figure 4B), although amounts of IFN-γ produced did not always correlate with B7H6 expression levels detected on these AML samples as, e.g., seen for MZ124 (see Figure 2A).