Chronic lymphocytic leukemia cells impair mitochondrial fitness in CD8+ T cells and impede CAR T-cell efficacy

In chronic lymphocytic leukemia (CLL), acquired T-cell dysfunction impedes development of effective immunotherapeutic strategies, through as-yet unresolved mechanisms. We have previously shown that CD8+ T cells in CLL exhibit impaired activation and reduced glucose uptake after stimulation. CD8+ T cells in CLL patients are chronically exposed to leukemic B cells, which potentially impacts metabolic homeostasis resulting in aberrant metabolic reprogramming upon stimulation. Here, we report that resting CD8+ T cells in CLL have reduced intracellular glucose transporter 1 (GLUT1) reserves, and have an altered mitochondrial metabolic profile as displayed by increased mitochondrial respiration, membrane potential, and levels of reactive oxygen species. This coincided with decreased levels of peroxisome proliferator-activated receptor coactivator 1-α, and in line with that, CLL-derived CD8+ T cells showed impaired mitochondrial biogenesis upon stimulation. In search of a therapeutic correlate of these findings, we analyzed mitochondrial biogenesis in CD19-directed chimeric antigen receptor (CAR) CD8+ T cells prior to infusion in CLL patients (who were enrolled in NCT01747486 and NCT01029366 [https://clinicaltrials.gov]). Interestingly, in cases with a subsequent complete response, the infused CD8+ CAR T cells had increased mitochondrial mass compared with nonresponders, which positively correlated with the expansion and persistence of CAR T cells. Our findings demonstrate tha...

Source: Blood - July 3, 2019 Category: Hematology Authors: van Bruggen, J. A. C., Martens, A. W. J., Fraietta, J. A., Hofland, T., Tonino, S. H., Eldering, E., Levin, M.-D., Siska, P. J., Endstra, S., Rathmell, J. C., June, C. H., Porter, D. L., Melenhorst, J. J., Kater, A. P., van der Windt, G. J. W. Tags: Immunobiology and Immunotherapy, Lymphoid Neoplasia Source Type: research