Characterization of autoantibody anti-melanoma differentiation associated gene 5 (anti-MDA5) in patients with dermatomyositis and polymyositis

Abstract

The idiopathic inflammatory myopathies (IIM) are a heterogeneous group of chronic autoimmune disease, systemic, associated with high morbidity and functional disability. Considering the clinical and histopathological features, the MII can be classified into polymyositis (PM), dermatomyositis (DM), inclusion body myositis (IBM), among others. The cause of both DM and PM remains unknown, but is believed to be multifactorial involving genetic, immunological and environmental. Thus, the presence of lymphocytic infiltrates in muscle tissue in most patients with IIM, as well as myositis-specific autoantibodies and myositis-associated circulation and deposits in the endothelial cells of blood vessels found in muscle biopsies, strongly suggest the involvement of processes in the pathogenesis of IIM immune compromising muscle function. On the other hand, the description of these autoantibodies has allowed a better characterization of the diagnosis of IIM, and extrapolate their possible associations with clinical, immunogenic, evolution, and prognosis.Among these autoantibodies, the anti-melanoma differentiation associated gene 5 (MDA5) has been described only recently. Apparently this autoantibody correlates with (a) patients with clinically amyopathic DM who have rapidly progressive pulmonary involvement; (b) cutaneous lesions, articular, pulmonary involvements and/or worse prognosis of patients with IIM.However, to date, no reports of evaluation of the profile and the distribution of this autoantibody anti-MDA5 in the Brazilian population with DM / PM and its clinical association. Thus, it would be of interest to establish a comparison of the reactivity pattern of our patients with that already described in other populations.