Depletion of CLL cells by venetoclax treatment reverses oxidative stress and impaired glycolysis in CD4 T cells

Acquired T-cell dysfunction is characteristic of chronic lymphocytic leukemia (CLL) and is associated with reduced efficacy of T cell-based therapies. A recently described feature of dysfunctional CLL-derived CD8 T cells is reduced metabolic plasticity. To what extend CD4 T cells are affected and whether CD4 T-cell metabolism and function can be restored upon clinical depletion of CLL cells are currently unknown. We address these unresolved issues by comprehensive phenotypic, metabolic, transcriptomic, and functional analysis of CD4 T cells of untreated patients with CLL and by analysis of the effects of venetoclax plus obinutuzumab on the CD4 population. Resting CD4 T cells derived from patients with CLL expressed lower levels of GLUT-1 and displayed deteriorated oxidative phosphorylation (OXPHOS) and overall reduced mitochondrial fitness. Upon T-cell stimulation, CLL T cells were unable to initiate glycolysis. Transcriptome analysis revealed that depletion of CLL cells in vitro resulted in upregulation of OXPHOS and glycolysis pathways and restored T-cell function in vitro. Analysis of CD4 T cells frompatients with CLL before and after venetoclax plus obinutuzumab treatment, which led to effective clearance of CLL in blood and bonemarrow, revealed recovery of T-cell activation and restoration of the switch to glycolysis, as well as improved T-cell proliferation. Collectively, these data demonstrate that CLL cells impose metabolic restrictions on CD4 T cells, which leads to reduced CD4 T-cell functionality. This trial was registered in the Netherlands Trial Registry as #NTR6043.

Automated summary

Patients with chronic lymphocytic leukemia (CLL) exhibit reduced functionality of CD4 T cells due to metabolic restrictions imposed by CLL cells. Treatment with venetoclax plus obinutuzumab can restore T-cell activation and switch to glycolysis, as well as improve T-cell proliferation.