Giant cell arteritis and polymyalgia rheumatica: Role of cytokines in the pathogenesis and implications for treatment

Objective: To summarize the contribution of cytokines to pathogenesis, clinical manifestations and prognosis of polymyalgia rheumatica (PMR) and giant cell arteritis (GCA).Methods: MEDLINE database search for studies published between 1980 and April 2008.Results: PMR and GCA are characterized by a hyperproduction of IL-6. The role of other circulating cytokines in their pathogenesis remains unclear. Cytokine mRNA in the arterial wall of GCA can distinguish different clinical subgroups of patients. The profile of T cell-derived cytokines in GCA suggests that it is a Th1-driven disease. The scarce number of studies makes difficult to evaluate the exact contribution of cytokine polymorphisms to their pathogenesis. Small studies have suggested the utility of TNF antagonists in patients with refractory PMR and GCA. However, these data have not been confirmed in controlled studies in patients with recent onset disease.Conclusion: Further studies are needed to evaluate the role of circulating cytokines in PMR and GCA. The study of tissue cytokines has provided important insights into the mechanisms implicated in the local inflammatory response that occurs in GCA. The important advance in the knowledge of the role of cytokines in PMR and GCA will have clear implications for treatment.