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Cytotherapy. 2016 Jul;18(7):893-901. doi: 10.1016/j.jcyt.2016.04.003. Epub 2016 May 17.

Myeloid cells in peripheral blood mononuclear cell concentrates inhibit the expansion of chimeric antigen receptor T cells.

Author information

1
Cell Processing Section, Department of Transfusion Medicine, National Institutes of Health Clinical Center, Bethesda, MD, USA. Electronic address: dstroncek@cc.nih.gov.
2
Cell Processing Section, Department of Transfusion Medicine, National Institutes of Health Clinical Center, Bethesda, MD, USA.
3
Pediatric Oncology Branch, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD, USA.

Abstract

BACKGROUND AIMS:

Autologous chimeric antigen receptor (CAR) T-cell therapies have shown promising clinical outcomes, but T-cell yields have been variable. CD19- and GD2-CAR T-cell manufacturing records were reviewed to identify sources of variability.

METHODS:

CD19-CAR T cells were used to treat 43 patients with acute lymphocytic leukemia or lymphoma and GD2-CAR T cells to treat eight patients with osteosarcoma and three with neuroblastoma. Both types of CAR T cells were manufactured using autologous peripheral blood mononuclear cells (PBMC) concentrates and anti-CD3/CD28 beads for T-cell enrichment and simulation.

RESULTS:

A comparison of the first 6 GD2- and the first 22 CD19-CAR T-cell products manufactured revealed that GD2-CAR T-cell products contained fewer transduced cells than CD19-CAR T-cell products (147 ± 102 × 10(6) vs 1502 ± 1066 × 10(6); P = 0.0059), and their PBMC concentrates contained more monocytes (31.4 ± 12.4% vs 18.5 ± 13.7%; P = 0.019). Among the first 28 CD19-CAR T-cell products manufactured, four had poor expansion yielding less than 1 × 10(6) transduced T cells per kilogram. When PBMC concentrates from these four patients were compared with the 24 others, PBMC concentrates of poorly expanding products contained greater quantities of monocytes (39.8 ± 12.9% vs. 15.3 ± 10.8%, P = 0.0014). Among the patients whose CD19-CAR T cells expanded poorly, manufacturing for two patients was repeated using cryopreserved PBMC concentrates but incorporating a monocyte depleting plastic adherence step, and an adequate dose of CAR T cells was produced for both patients.

CONCLUSIONS:

Variability in CAR T-cell expansion is due, at least in part, to the contamination of the starting PBMC concentrates with monocytes.

KEYWORDS:

CD19; GD2; acute lymphocytic leukemia; adoptive cellular therapy; chimeric antigen receptor T cells; osteosarcoma

PMID:
27210719
PMCID:
PMC4898642
DOI:
10.1016/j.jcyt.2016.04.003
[Indexed for MEDLINE]
Free PMC Article

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