title: Antinuclear Matrix Protein 2 Autoantibodies and Edema, Muscle Disease, and Malignancy Risk in Dermatomyositis Patients.
abstract: Dermatomyositis (DM) patients typically present with proximal weakness and autoantibodies that are associated with distinct clinical phenotypes. We observed that DM patients with autoantibodies recognizing the nuclear matrix protein NXP-2 often presented with especially severe weakness. The aim of this study was to characterize the clinical features associated with anti-NXP-2 autoantibodies.
  
  
  
  There were 235 DM patients who underwent testing for anti-NXP-2 autoantibodies. Patient characteristics, including muscle strength, were compared between those with and without these autoantibodies. The number of cancer cases observed in anti-NXP-2-positive subjects was compared with the number expected in the general population.
  
  
  
  Of the DM patients, 56 (23.8%) were anti-NXP-2-positive. There was no significant difference in the prevalence of proximal extremity weakness in patients with and without anti-NXP-2. In contrast, anti-NXP-2-positive patients had more prevalent weakness in the distal arms (35% versus 20%; P = 0.02), distal legs (25% versus 8%; P < 0.001), and neck (48% versus 23%; P < 0.001). Anti-NXP-2-positive subjects were also more likely to have dysphagia (62% versus 35%; P < 0.001), myalgia (46% versus 25%; P = 0.002), calcinosis (30% versus 17%; P = 0.02), and subcutaneous edema (36% versus 19%; P = 0.01) than anti-NXP-2-negative patients. Five anti-NXP-2-positive subjects (9%) had cancer-associated myositis, representing a 3.68-fold increased risk (95% confidence interval 1.2-8.6) compared to the expected prevalence in the general population.
  
  
  
  In DM, anti-NXP-2 autoantibodies are associated with subcutaneous edema, calcinosis, and a muscle phenotype characterized by myalgia, proximal and distal weakness, and dysphagia. As anti-NXP-2-positive patients have an increased risk of cancer, we suggest that they undergo comprehensive cancer screening.
authors.affiliation: Johns Hopkins University School of Medicine, Baltimore, Maryland.
authors.forename: Jemima
authors.initials: J
authors.lastname: Albayda
authors.affiliation: National Institute of Arthritis and Musculoskeletal and Skin Diseases, NIH, Bethesda, Maryland.
authors.forename: Iago
authors.initials: I
authors.lastname: Pinal-Fernandez
authors.affiliation: National Institute of Arthritis and Musculoskeletal and Skin Diseases, NIH, Bethesda, Maryland.
authors.forename: Wilson
authors.initials: W
authors.lastname: Huang
authors.affiliation: National Institute of Arthritis and Musculoskeletal and Skin Diseases, NIH, Bethesda, Maryland.
authors.forename: Cassie
authors.initials: C
authors.lastname: Parks
authors.affiliation: Johns Hopkins University School of Medicine, Baltimore, Maryland.
authors.forename: Julie
authors.initials: J
authors.lastname: Paik
authors.affiliation: Johns Hopkins University School of Medicine, Baltimore, Maryland.
authors.forename: Livia
authors.initials: L
authors.lastname: Casciola-Rosen
authors.affiliation: Johns Hopkins University School of Medicine, Baltimore, Maryland.
authors.forename: Sonye K
authors.initials: SK
authors.lastname: Danoff
authors.affiliation: Johns Hopkins University School of Medicine, Baltimore, Maryland.
authors.forename: Cheilonda
authors.initials: C
authors.lastname: Johnson
authors.affiliation: Johns Hopkins University School of Medicine, Baltimore, Maryland.
authors.forename: Lisa
authors.initials: L
authors.lastname: Christopher-Stine
authors.affiliation: Johns Hopkins University School of Medicine, Baltimore, Maryland, and National Institute of Arthritis and Musculoskeletal and Skin Diseases, NIH, Bethesda, Maryland.
authors.forename: Andrew L
authors.initials: AL
authors.lastname: Mammen
mesh_terms: D000251:Adenosine Triphosphatases / Q000097:blood*; D000328:Adult; D000974:Antibodies, Antinuclear / Q000097:blood*; D001323:Autoantibodies / Q000097:blood*; D002114:Calcinosis / Q000097:blood / Q000175:diagnosis / Q000453:epidemiology; D015331:Cohort Studies; D004268:DNA-Binding Proteins / Q000097:blood*; D003882:Dermatomyositis / Q000097:blood* / Q000175:diagnosis / Q000453:epidemiology; D004487:Edema / Q000097:blood* / Q000175:diagnosis / Q000453:epidemiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018908:Muscle Weakness / Q000097:blood* / Q000175:diagnosis / Q000453:epidemiology; D011446:Prospective Studies; D012307:Risk Factors
chemical_list: D000974:Antibodies, Antinuclear; D001323:Autoantibodies; D004268:DNA-Binding Proteins; D000251:Adenosine Triphosphatases; C551732:MORC3 protein, human