Ricerc@Sapienza

Anti-synthetase syndrome is an autoimmune disease characterized by autoantibodies toward amino acyl-tRNA synthetases (ARS), anti-Jo 1 being the most commonly detected. Muscle damage develops in up to 90% of ARS-positive patients, characterized by a necrotizing myositis restricted to the perifascicular region. This topographic distribution of muscle damage may lead to a misdiagnosis of DM at muscle biopsy. Despite similar clinical and morphological presentation, DM and ASS have a different prognosis, for instance, patients with ASS are prone to develop more aggressive complications requiring multi-modality immunosuppressive therapy. Aim of the present study will be to compare morphological, immunohistochemical and histoenzymatic features of muscle from ASS patients with those of DM ones. In addition, since a vasculopathy characterized by C5b9 deposition has been demonstrated both in DM and ARS-associated myositis, we will investigate capillary density both in the peripheral and central portion of the muscle fascicle. Finally, we will evaluate markers of mitochondrial damage to provide a further distinction between the two diseases.