Relapsed/refractory T-cell acute lymphoblastic leukemia (T-ALL) has a dismal outcome, and no effective targeted immunotherapies for T-ALL exist. The extension of chimeric antigen receptor (CAR) T cells (CARTs) to T-ALL remains challenging because the shared expression of target antigens between CARTs and T-ALL blasts leads to CART fratricide. CD1a is exclusively expressed in cortical T-ALL (coT-ALL), a major subset of T-ALL, and retained at relapse. This article reports that the expression of CD1a is mainly restricted to developing cortical thymocytes, and neither CD34+ progenitors nor T cells express CD1a during ontogeny, confining the risk of on-target/off-tumor toxicity. We thus developed and preclinically validated a CD1a-specific CAR with robust and specific cytotoxicity in vitro and antileukemic activity in vivo in xenograft models of coT-ALL, using both cell lines and coT-ALL patient–derived primary blasts. CD1a-CARTs are fratricide resistant, persist long term in vivo (retaining antileukemic activity in re-challenge experiments), and respond to viral antigens. Our data support the therapeutic and safe use of fratricide-resistant CD1a-CARTs for relapsed/refractory coT-ALL.

Most patients with acute myeloid leukemia (AML) and t(8;21) or inv(16) have a good prognosis with current anthracycline-and cytarabine-based protocols. Tandem analysis with flow cytometry (FC) and real-time RT-PCR (RQ-PCR) was applied to 55 patients, 28 harboring a t(8;21) and 27 an inv(16), including one case with a novel CBFbeta/MYH11 transcript. A total of 31% (n ¼ 17) of CR patients relapsed: seven with t(8;21) and 10 with inv(16). The mean amount of minimal residual disease (MRD) detected by FC in relapsed and nonrelapsed patients was markedly different: 0.3 vs 0.08% (P ¼ 0.002) at the end of treatment. The mean number of fusion transcript copies/ ABLx10 4 also differed between relapsed and non-relapsed patients: 2385 vs 122 (P ¼ 0.001) after induction, 56 vs 7.6 after intensification (P ¼ 0.0001) and 75 vs 3.3 (P ¼ 0.0001) at the end of chemotherapy. Relapses were more common in patients with FC MRD level 40.1% at the end of treatment than in patients with p0.1%: cumulative incidence of relapse (CIR) was 67 and 21% (P ¼ 0.03), respectively. Likewise, using RQ-PCR, a cutoff level of 410 copies at the end of treatment correlated with a high risk of relapse: CIR was 75% for patients with RQ-PCR 410 compared to 21% for patients with RQ-PCR levels p10 (P ¼ 0.04). Combined use of FC and RQ-PCR may improve MRD detection, and provide useful clinical information on relapse kinetics in AML patients.

These results suggest that lipid peroxidation and inflammation, but not hyperhomocysteinaemia, are the main risk factors for mortality in haemodialysis patients receiving vitamin supplements. As the study was carried out in a relatively limited number of patients, our findings need to be confirmed in a larger patient population.