In the case of synovial inflammation in RA, GzmK itself acts as a key inflammatory agent. GzmK induces synovial fibroblasts to activate proinflammatory pathways, including IL-6, CCL2, and ROS production. The protease activity of GzmK can also promote degradation of the ECM, leading to inflammatory cell infiltration and tissue destruction. This evidence concerns the gene GZMK and rheumatoid arthritis.