Chimeric antigen receptor-modified (CAR) T cells targeting CD19 (CART19) have shown therapeutical activities in CD19+ malignancies. However, the etiological nature of neurologic complications remains a conundrum. In our study, the evidence of blood-brain barrier (BBB)-penetrating CAR T cells as a culprit was revealed. A patient with acute lymphocytic leukemia developed sustained pyrexia with tremors about 6 h after CART19 infusion, followed by a grade 2 cytokine release syndrome (CRS) and neurological symptoms in the next 3 days. Contrast-enhanced magnetic resonance showed signs of intracranial edema. Lumbar puncture on day 5 showed an over 400-mmH2O cerebrospinal pressure. The cerebrospinal fluid (CSF) contained 20 WBCs/μL with predominant CD3+ T cells. qPCR analysis for CAR constructs showed 3,032,265 copies/μg DNA in CSF and 988,747 copies/μg DNA in blood. Cytokine levels including IFN-γ and IL-6 in CSF were extremely higher than those in the serum. Methyprednisone was administrated and the symptoms relieved gradually. The predominance of CART19 in CSF and the huge discrepancies in cytokine distributions indicated the development of a cerebral CRS, presumably featured as CSF cytokines largely in situ produced by BBB-penetrating CAR T cells. For the first time, we reported the development of cerebral CRS triggered by BBB-penetrating CAR T cells.Trial registration: ChiCTR-OCC-15007008.Electronic supplementary materialThe online version of this article (doi:10.1186/s13045-016-0299-5) contains supplementary material, which is available to authorized users.

Patients with relapsed/refractory acute lymphocytic leukemia (R/R ALL) have a poor prognosis. Chimeric antigen receptor-modified T cells against CD19 (CART19) have displayed anti-leukemia activities. However, data from systemic trials in Chinese patients are limited. T cells transduced with CD19-directed CAR lentiviral vectors were infused in patients with R/R ALL under fludarabine- and cyclophosphamide-based lymphodepletion. The postinfusion responses, toxicities, expansion, and persistence of CART19s in enrolled patients were observed and monitored. We enrolled 15 patients with R/R ALL. The median transduction efficiency of CART19s was 33%. cytotoxicity assays were conducted and showed prominent antileukemia activities with CART19s. The patients received CART19s infusion at doses of 1.1 × 10/kg to 9.8 × 10/kg. Twelve patients achieved complete remission 1 month after CART19s infusion. CART19s expanded and persisted in peripheral blood and bone marrow. At 150 days, the overall survival rate and leukemia-free survival rate were 65.5% and 37.8%, respectively. The cumulative incidence of relapse and the nonrelapse mortality rate were 54.5% and 7.7%, respectively. Four patients underwent subsequent haploidentical hematopoietic stem cell transplantation. In this trial, 10 patients experienced cytokine release syndrome (CRS). Grade 3 CRS developed in 40% of patients and was associated with a higher disease burden on day -1 and a higher number of previous relapses. This trial demonstrated potent antileukemia activities of CART19s in Chinese patients with R/R ALL. Disease relapse remained the main obstacle. However, patients with a high risk of relapse after CART19s might benefit from subsequent haploidentical hematopoietic stem cell transplantation. .

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Hypoxia-inducible factors (HIFs) are master regulators of adaptive responses to low oxygen, and their α-subunits are rapidly degraded through the ubiquitination-dependent proteasomal pathway after hydroxylation. Aberrant accumulation or activation of HIFs is closely linked to many types of cancer. However, how hydroxylation of HIFα and its delivery to the ubiquitination machinery are regulated remains unclear. Here we show that Rho-related BTB domain-containing protein 3 (RHOBTB3) directly interacts with the hydroxylase PHD2 to promote HIFα hydroxylation. RHOBTB3 also directly interacts with the von Hippel-Lindau (VHL) protein, a component of the E3 ubiquitin ligase complex, facilitating ubiquitination of HIFα. Remarkably, RHOBTB3 dimerizes with LIMD1, and constructs a RHOBTB3/LIMD1-PHD2-VHL-HIFα complex to effect the maximal degradation of HIFα. Hypoxia reduces the RHOBTB3-centered complex formation, resulting in an accumulation of HIFα. Importantly, the expression level of RHOBTB3 is greatly reduced in human renal carcinomas, and RHOBTB3 deficiency significantly elevates the Warburg effect and accelerates xenograft growth. Our work thus reveals that RHOBTB3 serves as a scaffold to organize a multi-subunit complex that promotes the hydroxylation, ubiquitination and degradation of HIFα.

Chimeric antigen receptor modified T cells against CD19 (CART19s) have potent anti-leukemia activities in patients with refractory/relapsed acute lymphoblastic leukemia (R/R ALL). This study was designed to investigate the correlation between safety/efficacy and therapeutic modalities including chemotherapy and CART19 therapy. Total 23 and 69 patients were enrolled in the CART19 group and in the chemotherapy group, respectively. The safety and efficacy profiles of 66 and 22 patients in the 2 groups were evaluated. The complete remission (CR) rate was higher in the CART19 group than that in the chemotherapy group (90.9 vs 37.9%, P = 0.000). For patients relapsed after allo-HSCT and chemotherapy, CR rates were 100% (8/8) vs 48.0% (12/25) (P = 0.009) and 85.7% (12/14) vs 31.7% (13/41) (P = 0.000), respectively. Moreover, a higher percentage in the CART19 group had results below the threshold for minimal residual disease (100 vs 7.58%, P = 0.000). In survival analysis, the overall survival rate at 12 months was higher in the CART19 group than that in the chemotherapy group (60.9 vs 10.1%, P = 0.000). For post-transplant patients achieving CR, 25.0% (2/8) and 75.0% (9/12) complicated with GVHD (P = 0.04) in the CART19 group and chemotherapy group, respectively. For all CR patients, the median duration of absolute neutrophil count less than 500/μL and platelet count less than 20,000/μL were longer in the CART19 group than in the chemotherapy group (p = 0.0047 and 0.0003, respectively). Our data demonstrated that patients with CART19s therapy acquired higher rates of remission and longer survival, confirming the encouraging application of CART19 therapy in R/R ALL.