A novel generation 1928zT2 CAR T cells induce remission in extramedullary relapse of acute lymphoblastic leukemia

J Hematol Oncol. 2018 Feb 20;11(1):25. doi: 10.1186/s13045-018-0572-x.


Background: Anti-CD19 chimeric antigen receptor (CAR) T cells have shown promise in the treatment of B cell acute lymphocytic leukemia (B-ALL). However, its efficacy in B-ALL patients with extramedullary involvement is limited due to poor responses and neurotoxicity. Here, we utilized a third generation of CAR T cell vector, which contains the Toll/interleukin-1 receptor (ITR) domain of Toll-like receptor 2 (TLR2), to generate 1928zT2 T cells targeting CD19, and evaluated the efficacy of 1928zT2 T cells in relapse or refractory B-ALL patients with extramedullary involvement.

Methods: 1928zT2 T cells were generated by 19-28z-TLR2 lentiviral vector transfection into primary human T lymphocytes. The anti-leukemia effect of 1928zT2 T cells were determined by killing assays and in xenografts. Three patients diagnosed as relapse or refractory ALL with extramedullary involvement were infused with 1928zT2 T cells, and the clinical responses were evaluated by BM smear, B-ultrasonography, PET/CT, histology, flow cytometry, qPCR, ELISA, and luminex assay.

Results: 1928zT2 T cells exhibited enhanced effector function against CD19+ leukemic cells in vitro and in a xenograft model of human extramedullary leukemia. Notably, the 1928zT2 T cells eradicated extramedullary leukemia and induced complete remission in the three relapse and refractory ALL patients without serious adverse effects. 1928zT2 T cells expanded robustly in the circulation of these three patients and were detected in the cerebrospinal fluid of patient 3. These three patients experienced cytokine release syndrome (CRS) with grade 2 or 3, which remitted spontaneously or after tocilizumab treatment. None of the three patients suffered neurotoxicity or needed further intensive care.

Conclusions: Our results demonstrate that 1928zT2 T cells with TLR2 incorporation augment anti-leukemic effects, particularly for eradicating extramedullary leukemia cells, and suggest that the infusion of 1928zT2 T cells is an encouraging treatment for relapsed/refractory ALL patients with extramedullary involvement.

Trial registration: ClinicalTrials.gov identifier NCT02822326 . Date of registration: July 4, 2016.

Keywords: Acute lymphocytic leukemia (ALL); Chimeric antigen receptor (CAR) T cells; Extramedullary ALL; Relapsed and refractory; TLR2.

Publication types

  • Clinical Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Animals
  • Antigens, CD19 / immunology
  • Cells, Cultured
  • Female
  • Humans
  • Immunotherapy, Adoptive / methods*
  • Male
  • Mice
  • Neoplasm Recurrence, Local / immunology
  • Neoplasm Recurrence, Local / pathology
  • Neoplasm Recurrence, Local / therapy*
  • Precursor Cell Lymphoblastic Leukemia-Lymphoma / immunology
  • Precursor Cell Lymphoblastic Leukemia-Lymphoma / pathology
  • Precursor Cell Lymphoblastic Leukemia-Lymphoma / therapy*
  • Receptors, Chimeric Antigen / genetics
  • Receptors, Chimeric Antigen / immunology*
  • T-Lymphocytes / immunology*
  • T-Lymphocytes / pathology
  • T-Lymphocytes / transplantation
  • Toll-Like Receptor 2 / genetics
  • Toll-Like Receptor 2 / immunology*
  • Transfection
  • Young Adult


  • Antigens, CD19
  • Receptors, Chimeric Antigen
  • TLR2 protein, human
  • Toll-Like Receptor 2

Associated data

  • ClinicalTrials.gov/NCT02822326