An anti-CD19/CTLA-4 switch improves efficacy and selectivity of CAR T cells targeting CD80/86-upregulated DLBCL.

Chimeric antigen receptor T cell (CAR T) therapy is a potent treatment for relapsed/refractory (r/r) B cell lymphomas but provides lasting remissions in only ∼40% of patients and is associated with serious adverse events. We identify an upregulation of CD80 and/or CD86 in tumor tissue of (r/r) diffuse large B cell lymphoma (DLBCL) patients treated with tisagenlecleucel. This finding leads to the development of the CAR/CCR (chimeric checkpoint receptor) design, which consists of a CD19-specific first-generation CAR co-expressed with a recombinant CTLA-4-linked receptor with a 4-1BB co-stimulatory domain. CAR/CCR T cells demonstrate superior efficacy in xenograft mouse models compared with CAR T cells, superior long-term activity, and superior selectivity in in vitro assays with non-malignant CD19+ cells. In addition, immunocompetent mice show an intact CD80-CD19+ B cell population after CAR/CCR T cell treatment. The results reveal the CAR/CCR design as a promising strategy for further translational study.

Haploidentical CD3 or α/ß T-cell depleted HSCT in advanced stage sickle cell disease.

Despite significant improvements in the supportive care, sickle cell disease (SCD) leads to significant morbidity and mortality. Allogeneic hematopoietic stem cell transplantation (HSCT), the only curative option, is limited due to matched donor availability. This could be met with T-cell-depleted haploidentical HSCT. Twenty advanced-stage SCD patients, median age 15 years, and 9 patients, median age 14 years, were transplanted with CD3/CD19- or TCRαß/CD19-depleted grafts and from matched sibling donors (MSDs). The conditioning consisted of ATG, thiotepa, fludarabine, and treosulfan. The median follow-up in the T-haplo-HSCT and the MSD patients was 21 (9-62) and 25 (7-60) months, respectively. The OS in the T-haplo-HSCT and MSD was 90% and 100%, respectively. In the T-haplo-HSCT group, two patient succumbed to a CMV pneumonitis and a macrophage activation syndrome (MAS). One patient in the T-haplo-HSCT group requires renal replacement therapy because of BK virus nephritis. None developed grade III-IV acute GvHD. In the T-haplo-HSCT and in the MSD, 20% and 22%, respectively, developed a mild or moderate chronic GvHD. These results demonstrate the feasibility, safety, and efficacy of T-haplo-HSCT also for adult advanced stage SCD patients.

Modification of Bupivacaine-Induced Myotoxicity with Dantrolene and Caffeine In Vitro.

BACKGROUND: Local anesthetics, especially bupivacaine, have myotoxic effects in clinically used concentrations and context. Detailed mechanisms of these effects are unknown, but an increase in intracellular calcium levels is suspected to be the most important trigger. Dantrolene and caffeine modify cellular calcium release from the sarcoplasmic reticulum. The aim of our study was to investigate the effect of dantrolene and caffeine on bupivacaine-induced myotoxicity in vitro. METHODS: A cell culture model of primary muscle cells of BALB/c AnNCrl mice was established. Cells were incubated simultaneously with increasing concentrations of bupivacaine, dantrolene, and caffeine. The fraction of dead cells was calculated after staining with propidium iodide and analysis by flow cytometry. The half-maximal inhibitory concentration of bupivacaine was calculated for each concentration. Group differences were determined by using 1-way analysis of variances with subsequent post hoc 1-way Dunnett t test. RESULTS: Both dantrolene and caffeine alone had no effect on muscle cell survival. Increasing concentrations of bupivacaine caused increasing cell death. Dantrolene dose-dependently reduced the fraction of necrotic cells, whereas caffeine dose-dependently increased the fraction of dead cells. CONCLUSIONS: Dantrolene attenuated, and caffeine enhanced, bupivacaine-induced myotoxicity, presumably by modifying sarcoplasmic calcium release. This indicates that intracellular calcium release is an important factor for local anesthetic-induced cell death.

The myotoxic effect of bupivacaine and ropivacaine on myotubes in primary mouse cell culture and an immortalized cell line.

BACKGROUND: The 2 local anesthetics (LAs) bupivacaine and ropivacaine have acute cytotoxic effects on different tissues. In this respect, LA-induced myotoxicity has been subject to various studies; however, the exact mechanisms are still not fully understood. Most in vitro studies use immortalized cell lines because of feasibility. Thus, establishing a primary cell line might result in more accurate results. In this study, we examined the effects of immortalization on bupivacaine- and ropivacaine-induced myotoxicity in vitro. METHODS: An immortalized (N = 6) and a primary cell line (N = 8) of the same tissue and species were established, and differentiation in myotubes was induced. Cells were exposed to increasing concentrations of bupivacaine and ropivacaine for 1 or 2 hours, respectively. Twenty-four and 48 hours after treatment, the fractions of dead and vital cells were measured using flow cytometry. Significance was tested through 1-way analysis of variance with post hoc Dunnett T3 test. Medians of dataset pairs were compared by T test. RESULTS: In both cell lines, increasing concentrations of both LAs resulted in decreased cell survival (e.g., P < 0.001 for 5000 ppm bupivacaine, 1 or 2 hours of incubation, and 24 hours recovery in both cell lines). For the same LA concentrations, survival was significantly higher in the immortalized cell culture (e.g., P < 0.001 for 2500 ppm ropivacaine, 1 hour of incubation, and 24 hours recovery). In addition, equal concentrations of bupivacaine resulted in significantly fewer vital cells compared with ropivacaine (e.g., P = 0.032 for 2500 ppm ropivacaine, 1 hour of incubation, and 24 hours recovery). Two hours of incubation resulted in a significantly higher rate of dead cells compared with 1 hour of incubation (e.g., P = 0.004 for C2C12 cells, 2500 ppm bupivacaine, and 24 hours recovery). CONCLUSIONS: Primary skeletal muscle cells are more vulnerable to LAs than immortalized cells. The higher myotoxic potential of bupivacaine compared with ropivacaine in vivo can be reproduced in vitro. Incubation time has an influence on cell survival.

Cell harvesting method influences results of apoptosis analysis by annexin V staining.

BACKGROUND: Annexin V staining is a common tool in apoptosis analysis. However, in adherently growing cell lines, substantial experimental bias could be introduced by membrane damage during the harvesting process. We investigated the influence of three different harvesting methods on the cell membrane integrity of six malignant cell lines. MATERIALS AND METHODS: Six malignant cell lines were detached enzymatically by standard trypsinization or mechanically by scraping or wash-down by water jet. Membrane damage was measured by annexin V staining. RESULTS: Three out of six cell lines (Mel-Ho, SW480 and PaTu 8988t) were not susceptible to membrane damage long the mothods used here. In HT 29, PANC 1 and A-673 cell lines, a high percentage of cells were stained positively for annexin V after mechanical detachment. These cells would wrongly be declared apoptotic cells. CONCLUSION: To avoid substantial experimental bias caused by membrane damage, we recommend pre-testing of different harvesting methods before performing apoptosis analysis.