CD8A and rheumatoid arthritis: These results are consistent with a recent study that investigated CD8+ T cell subsets in RA synovium51, showing that GZMK+ CD8+ T cells, which they termed CD8 TteK cells, were the predominant tissue-resident effector CD8+ T cell population in inflamed synovium and exhibited high cytokine production but low cytotoxic potential compared to GZMB + CD8+ T cells.