IL17A and arthritic joint disease: Indeed, IL-17-mediated activation of MMPs has been demonstrated to play a role in a number of inflammatory conditions including inflammation of mouse airways [25], cartilage destruction in mouse models of arthritis [26,27], hepatocellular carcinoma metastasis [28] and inflammation associated with human atherosclerosis [29], a condition that has been linked to C. pneumoniae infection [30].