GZMB and B-cell chronic lymphocytic leukemia: Functional investigation of TR1 cells in TCL1 AT mice confirmed the phenotype observed in CLL patients, with an induced IL-10 expression that increased over time (Fig. 4B and Supplementary Fig. 5E), and higher levels of IFNγ, CD107a, and GzmB (Supplementary Fig. 5F, G), as markers of cytotoxicity, in these cells.