GZMB and rheumatoid arthritis: Further, we found that not only the proportion of total CD8+ T cells, GzmB or KIR2DL3-expressing CD8+ T cells or EMRA CD8+ T cell subsets, but also the absolute cell counts of these activated cytotoxic CD8+ cells, are increased in ACPA+ RA blood as compared to HC (Supplementary Fig. 3).