[From pathogenesis of giant cell arteritis to new therapeutic targets]

Giant cell arteritis (GCA) is the most common vasculitis in adults. GCA is a granulomatous large-vessel vasculitis involving the aorta and its major branches in people>50 years. Glucocorticoids (GC) remain the cornerstone of GCA treatment. Prednisone is usually started at 0.7 or 1mg/kg/day depending on the occurrence of ischemic complications. Then, GC are progressively tapered and stopped after a mean duration of 18 months. GC are very efficient but relapses often occur during their tapering. Moreover, GC-related side effects are very common during this long term GC therapy. Thus, it can be assumed that GC are not the ideal treatment for GCA and that GC-sparing strategies have to be developed. The pathogenesis of GCA is not fully understood but major advances have been achieved in the recent years. If the trigger of GCA, which is suspected to be infectious, is still not identified, mechanisms triggering the granulomatous inflammation of the arterial wall and the progressive vascular remodeling leading to the occurrence of ischemic events have been better and better deciphered. Thanks to these advances in the knowledge of GCA pathogenesis, new therapeutic targets have emerged such as blockade of the activation of T cells or inhibition of the interleukin-6 (IL-6), IL-12/23 or IL-1β pathways.