Cytotoxicity and exhaustion markers of chimeric antigen receptor T cells targeting BCMA in multiple myeloma cell lines between patients and healthy donors.

OBJECTIVES: Multiple myeloma (MM) accounts for 10% of hematologic malignancies. However, most of the patients suffered from relapsed/refractory disease. We would like to expand CAR T cell therapy to treat MM using our current platform. METHODS: BCMA CAR T lymphocytes were generated for volunteers or MM patients. The transduction efficiency was detected by the ddPCR technique. Immunophenotyping and exhaustion markers were monitored by flow cytometry. The efficacy of BCMA CAR T cells was tested using coculturing with BCMA CAR or mock, and the positive and negative targets, K562/hBCMA-ECTM and K562, respectively. RESULTS: BCMA CAR T cells were generated from consented volunteers or MM patients and could be detected CAR BCMA expression at a mean of 4.07 ± 1.95 or 4.65 ± 1.21 copies/cell, respectively. Those modified T cells were primarily effector memory T cells. Our BCMA CAR T cells could explicitly eradicate the K562/hBCMA-ECTM cell line while the K562 cell line survived. Interestingly, the BCMA CAR, mock T cells, and peripheral blood mononuclear cells from MM patients expressed similar levels of the exhaustion makers, TIM-3, LAG-3, and PD1. CONCLUSIONS: Our BCMA CAR T cells, mainly effector/effector memory, could eliminate BCMA-expressing cells in vitro and had similar levels of exhaustion markers among different populations.

Alteration of monocyte subsets and their functions in thalassemia patients.

Infection is one of the leading causes of mortality in thalassemia patients. This study aimed to examine qualitative and quantitative changes in monocytes in thalassemia patients. Monocytes were isolated from peripheral blood mononuclear cells and separated into subpopulations by flow cytometry. Cytokine levels were measured using quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR) and sandwich enzyme-linked immunosorbent assay (ELISA). The primary endpoint was monocyte-derived TNF-α expression. A total of 78 patients and 26 controls were included. The mean log (TNF-α fold-change) by qRT-PCR was significantly lower in all thalassemia groups, at 1.27 in controls, versus 0.97 (p = 0.0014) in non-transfusion-dependent thalassemia (NTDT), 0.96 (p = 0.0004) in non-splenectomized transfusion-dependent thalassemia (TDT-NS), and 0.87 (p < 0.0001) in splenectomized transfusion-dependent thalassemia (TDT-S). Similarly, the mean 2-h TNF-α level measured by sandwich ELISA assay was significantly lower in all thalassemia groups, at 98.16 pg/mL in controls, versus 56.45 pg/mL (p = 0.0093) in NTDT, 39.05 pg/mL (p = 0.0001) in TDT-NS and 32.37 pg/mL (p < 0.0001) in TDT-S. Likewise, TDT patients had a significantly decreased percentage of non-classical monocytes, by approximately half compared to controls. Our results show that thalassemia major patients have clearly impaired monocyte counts and function.