Monocytes M( MP )aking Way for T-Cell Vascular Infiltration

Giant cell arteritis (GCA) is a chronic inflammatory vasculopathy of the medium and large-sized arteries including the external carotid branches, the ophthalmic, vertebral, subclavian, and axillary arteries, as well as thoracic aorta. Severe granulomatous vasculitis, with profound T cell and macrophage activation and infiltration into the otherwise immunoprivileged vascular wall, results in occlusion of vascular lumen leading to ischemic symptoms, such as loss of vision in ca. 15% of patients. Dissection and aneurysm formation, especially in the aorta also occur. Although very long-term high-dose glucocorticosteroid treatments are used in controlling the inflammation to alleviate symptoms, they are associated with complications, and when glucocorticoids are gradually reduced, disease flares occur frequently. Thus, glucocorticoid sparing regimens including methotrexate as well as biologics such as tocilizimab or abatacept have been tested to further reduce risk of relapse and lower serious systemic side effects. A need for additional potentially safer therapies is very evident.