Transcriptional signatures associated with persisting CD19 CAR-T cells in children with leukemia.

In the context of relapsed and refractory childhood pre-B cell acute lymphoblastic leukemia (R/R B-ALL), CD19-targeting chimeric antigen receptor (CAR)-T cells often induce durable remissions, which requires the persistence of CAR-T cells. In this study, we systematically analyzed CD19 CAR-T cells of 10 children with R/R B-ALL enrolled in the CARPALL trial via high-throughput single-cell gene expression and T cell receptor sequencing of infusion products and serial blood and bone marrow samples up to 5 years after infusion. We show that long-lived CAR-T cells developed a CD4/CD8 double-negative phenotype with an exhausted-like memory state and distinct transcriptional signature.

Enhanced CAR T cell expansion and prolonged persistence in pediatric patients with ALL treated with a low-affinity CD19 CAR.

Chimeric antigen receptor (CAR)-modified T cells targeting CD19 demonstrate unparalleled responses in relapsed/refractory acute lymphoblastic leukemia (ALL), but toxicity, including cytokine-release syndrome (CRS) and neurotoxicity, limits broader application. Moreover, 40-60% of patients relapse owing to poor CAR T cell persistence or emergence of CD19 clones. Some factors, including the choice of single-chain spacer and extracellular and costimulatory domains, have a profound effect on CAR T cell function and persistence.

Optimization of methodology for production of CD25/CD71 allodepleted donor T cells for clinical use.

Background Aims: Immunotherapy with allodepleted donor T cells improves immunity after T cell-depleted hematopoietic stem cell transplantation. We developed a methodology for selective depletion of alloreactive T cells after activation with host antigen-presenting cells by targeting T cells up-regulating CD25 and CD71. Combined depletion of these cells yields a pool of allodepleted donor T cells with antiviral properties with minimal capacity to cause graft-versus-host disease.

Simultaneous generation of multivirus-specific and regulatory T cells for adoptive immunotherapy.

Previous studies have established that adoptive immunotherapy with donor-derived virus-specific T cells can prevent/treat viral complications post-stem cell transplant and regulatory T cells show promise as inhibitors of graft-versus-host disease. On the basis of flow cytometric analysis of upregulation of activation markers after stimulation with viral peptide pools, we have developed a rapid and clinically applicable protocol for the simultaneous selection of virus-specific T cells (after stimulation with peptide pools for the immunodominant antigens of cytomegalovirus, Epstein-Barr virus, and adenovirus) and regulatory T cells using CD25 immunomagnetic selection. Using tetramer staining, we detected enrichment of CD8 T cells recognizing peptide epitopes from cytomegalovirus and Epstein-Barr virus antigens after CD25 selection in 6 of 7 donors.