Single VHH-directed BCMA CAR-NK cells for multiple myeloma

Abstract Natural killer (NK) cells are promising alternatives for the production of “off-the-shelf” CAR products, posing a lower risk of cytokine release syndrome (CRS) than CAR-T cells. We synthesized four single VHH-directed anti-BCMA CARs, incorporating various intracellular regions (2B4 versus CD28) and hinge domains (CD28 versus IgG1) and ectopically producing IL-15. NK cells derived from peripheral blood (PB) were expanded ex vivo by K562-mbIL21 feeder cells. Stable CAR transduction was obtained through lentiviral transduction with the BaEV-Rless pseudotyped lentiviral vector. BCMA-CD28-IL15 CAR-NK cells with ectopic expression of IL-15 exhibited superior cytotoxicity were compared to BCMA-CD28 CAR-NK cells lacking IL-15 and BCMA-hIgG1-IL15 CAR-NK cells with an IgG1 hinge domain. We further assessed the cytotoxic capabilities of BCMA-2B4-IL15 CAR-NK cells with 2B4 intracellular domain. The BCMA-CD28-IL15 CAR-NK cells revealed stronger cytotoxicity and higher cytokine secretion against BCMA+ tumor cells than BCMA-2B4-IL15 CAR-NK cells in vitro. In the MM.1S-Luc mouse model, BCMA-CD28-IL15 CAR-NK inhibited the growth of tumor cells and prolonged mouse survival. These results show that the single VHH-directed BCMA CAR-NK cells exhibited remarkable specific killing ability, making them a potential candidate for immunotherapy in multiple myeloma treatment

Additional file 1 of Single VHH-directed BCMA CAR-NK cells for multiple myeloma

Supplementary Material

Feasibility of reduced-dose posttransplant cyclophosphamide and cotransplantation of peripheral blood stem cells and umbilical cord-derived mesenchymal stem cells for SAA

Abstract Posttransplant cyclophosphamide (PTCy) as graft-versus-host disease (GVHD) prophylaxis is an effective strategie for patients receiving matched sibling donor hematopoietic stem cell transplantation (MSD-HSCT) and haploidentical HSCT (haplo-HSCT). We evaluated the effectiveness and safety of reduced-dose cyclophosphamide, 20 mg/kg for 13 patients in MSD-HSCT cohort and 25 mg/kg for 22 patients in haplo-HSCT cohort, on days + 3, + 4 combined with cotransplantation of peripheral blood stem cells (PBSCs) and human umbilical cord-derived mesenchymal stem cells (UC-MSCs) for severe aplastic anemia (SAA). In MSD-PTCy cohort, the times to neutrophil and platelet engraftment were significantly shorter than those in the MSD-control cohort (P < 0.05). The cumulative incidence of acute GVHD (aGVHD) at day + 100 (15.4%) was lower than that in the MSD-control cohort (P = 0.050). No patient developed chronic GVHD (cGVHD). The 1-year overall survival (OS) and event-free survival (EFS) rates were 100% and 92.3%. In haplo-PTCy cohort, the times to neutrophil and platelet engraftment were significantly shorter than those in the haplo-control cohort (P < 0.05). The cumulative incidences of aGVHD at day + 100 and 1-year cGVHD were 31.8% and 18.2%, and the 1-year OS and EFS rates were 81.8% and 66.9%. Reduced-dose PTCy and cotransplantation of PBSCs and UC-MSCs is an acceptable alternative to patients with SAA