Role of autoimmunity and autoinflammation in the pathogenesis of idiopathic recurrent pericarditis.

Idiopathic recurrent pericarditis is the most common and troublesome complication of acute pericarditis affecting about one third of such patients. The pericardium may be involved in different systemic autoimmune diseases (i.e., systemic lupus erythematosus, rheumatoid arthritis, progressive systemic sclerosis, mixed connective tissue disease, Sjogren's Syndrome, polyarteritis, giant cell arteritis, other systemic vasculitides) either in a symptomatic form (usually during the active phase of the disease) or as asymptomatic pericardial effusion. Moreover, idiopathic recurrent pericarditis mimicks hereditary periodic fever syndromes (HPFSs). HPFSs are a group of disorders characterized by primary dysfunction of the innate immune system mostly caused by mutations of genes involved in the regulation or activation of the inflammatory response, without any apparent involvement of antigen-specific T cells or significant production of autoantibodies. These disorders usually manifest in the pediatric population, with onset ranging from the first hours to the first decade of life, however a limited number of patients experience disease onset during adulthood.