Anti-Jo-1 antibody-positive patients show a characteristic necrotizing perifascicular myositis

Abstract

Idiopathic inflammatory myopathies can be classified as polymyositis, dermatomyositis, immune-mediated necrotizing myopathy, sporadic inclusion body myositis or non-specific myositis. Anti-Jo-1 antibody-positive patients are assigned to either polymyositis or dermatomyositis suggesting overlapping pathological features. We aimed to determine if anti-Jo-1 antibody-positive myopathy has a specific morphological phenotype. In a series of 53 muscle biopsies of anti-Jo-1 antibody-positive patients, relevant descriptive criteria defining a characteristic morphological pattern were identified. They were tested in a second series of anti-Jo-1 antibody-positive patients and compared to 63 biopsies from patients suffering from other idiopathic inflammatory myopathies. In anti-Jo-1 antibody-positive patients, necrotic fibres, which strongly clustered in perifascicular regions, were frequently observed. Sarcolemmal complement deposition was detected specifically in perifascicular areas. Inflammation was mainly located in the perimysium and around vessels in 90.6%. Perimysial fragmentation was observed in 90% of cases. Major histocompatibility complex class I staining was diffusely positive, with a perifascicular reinforcement. Multivariate analysis showed that criteria defining perifascicular pathology: perifascicular necrosis, atrophy, and perimysial fragmentation allow the distinction of anti-Jo-1 antibody-positive patients, among patients suffering from other idiopathic inflammatory myopathies. Anti-Jo-1 antibody-positive patients displayed perifascicular necrosis, whereas dermatomyositis patients exhibited perifascicular atrophy.

Clinical features and prognosis in anti-SRP and anti-HMGCR necrotising myopathy

“…In no patient with IBM except one, who had anti-HMGCR antibodies, were these three autoantibodies detected. IIMs except for IBM (n=387) were further divided into polymyositis (n=19), dermatomyositis (n=56), IMNM (n=177), antisynthetase syndrome (n=51) and non-specific myositis (n=84), since anti-synthetase syndrome is a clinically and pathologically distinct disease entity 18 19. Thus, anti-SRP and anti-HMGCR antibodies were found in 39% (69/177) and 26% (46/177) of the patients with IMNM.…”

Integrated classification of inflammatory myopathies

“…Complement is deposited on the sarcolemma of myofibres adjacent to the perimysium. In summary, there is overwhelming evidence to support separate classification of this entity rather than as a variant of DM or PM . Interestingly, ASS‐associated myositis seems to be quite homogeneous as far as morphology is concerned .…”

213th ENMC International Workshop: Outcome measures and clinical trial readiness in idiopathic inflammatory myopathies, Heemskerk, The Netherlands, 18–20 September 2015

“…However, patients with anti-Jo-1 autoantibodies also have prominent muscle fiber necrosis and HLA-II expression in perifascicular regions [24–26]. Patients with anti-Jo-1 autoantibodies have a perifascicular necrotizing myositis [25]. Furthermore, these patients also frequently have a unique morphologic hallmark of myonuclear actin filament inclusions [26].…”