Considering the heterogeneous nature of CD8+ T cells, we observed that even CD26low/highCD8+ T cells with effector and effector memory phenotype showed substantial downregulation of perforin/GzmB compared to their CD26neg counterparts in CLL patients (Additional file 1: l Fig. S3b–d). The gene discussed is GZMB; the disease is B-cell chronic lymphocytic leukemia.