Anti-Cortactin Autoantibodies Are Associated With Key Clinical Features in Adult Myositis But Are Rarely Present in Juvenile Myositis.

Abstract

To define the prevalence and clinical phenotype of anti-cortactin autoantibodies in adult and juvenile myositis. In this longitudinal cohort study, anti-cortactin autoantibody titers were assessed by enzyme-linked immunosorbent assay in 670 adult myositis patients and 343 juvenile myositis patients as well as in 202 adult healthy controls and 90 juvenile healthy controls. The prevalence of anti-cortactin autoantibodies was compared among groups. Clinical features of patients with and those without anti-cortactin autoantibodies were also compared. Anti-cortactin autoantibodies were more common in adult dermatomyositis (DM) patients (15%; P=0.005), particularly those with coexisting anti-Mi-2 autoantibodies (24%; P=0.03) or anti-NXP-2 autoantibodies (23%; P=0.04). In adult myositis, anti-cortactin was associated with DM skin involvement (62% of patients with anti-cortactin versus 38% of patients without anti-cortactin; P=0.03), dysphagia (36% versus 17%; P=0.02) and coexisting anti-Ro 52 autoantibodies (47% versus 26%; P=0.001) or anti-NT5c1a autoantibodies (59% versus 33%; P=0.001). Moreover, the titers of anti-cortactin antibodies were higher in patients with interstitial lung disease (0.15 versus 0.12 arbitrary units; P=0.03). The prevalence of anti-cortactin autoantibodies was not different in juvenile myositis patients (2%) or in any juvenile myositis subgroup compared to juvenile healthy controls (4%). Nonetheless, juvenile myositis patients with these autoantibodies had a higher prevalence of "mechanic's hands" (25% versus 7%; P=0.03), a higher number of hospitalizations (2.9 versus 1.3; P=0.04), and lower peak creatine kinase values (368 versus 818 IU/liter; P=0.02) than those without anti-cortactin. The prevalence of anti-cortactin autoantibodies is increased in adult DM patients with coexisting anti-Mi-2 or anti-NXP-2 autoantibodies. In adults, anti-cortactin autoantibodies are associated with dysphagia and interstitial lung disease.