CD4 and leukemia: Further analysis of T cell subsets in tumor tissues by mass cytometry revealed that the percentages of granzyme B+ CD8+ T cells as well as effector memory phenotype (CD44+CD62L–) CD8+ T cells were significantly increased, although there was no significant increase of total CD8+ or CD4+ T cell infiltration in PD-1H–positive leukemia after 13F3 treatment compared with controls (Figure 4G).