Etiopathogenesis of giant cell arteritis

Abstract

Giant cell arteritis is a vasculitis of large and medium size arteries, especially those of the aortic arch with an extracranial distribution, but also the aorta and some of its larger branches. It is characterised by the presence of mononuclear inflammatory infiltrates close to the internal elastic lamina formed by lymphocytes and macrophages, which in slightly more than 50% of the cases contain multinucleate giant cells. The morbidity associated with this disease is related to phenomena of distal ischemia to the luminal stenosis of the inflamed arteries, and to a lesser extent to the formation of aneurisms due to the weakening of the arterial wall. With an unknown aetiology, its pathogenesis is immune through the migration and location of γ-INF -producing T cells in the adventitia of the inflamed arteries, it being assumed that this is the place of immune stimulation by a still unidentified antigen. The recruitment and activation of macrophages by this cytokine is one of the most important points of its pathogenesis. The destruction by these of the arterial elastic tissue is a relevant phenomenon, as is the production of other factors promoting neoangiogenesis and a proliferation of neointime, responsible through obliterating light for the ischemic manifestations of the disease. The process is accompanied by an important systemic repercussion characterised by a strong reaction of acute phase and general but barely specific symptoms of disease. On the other hand, an important percentage of patients show a clinical picture of polymyalgia rheumatica, an entity that has a historical and controversial relationship to this arteritis. In recent years important contributions have been made to the understanding of the immune mechanisms involved in its pathogenesis.