Anti-nuclear matrix protein 2 antibody-positive inflammatory myopathies represent extensive myositis without dermatomyositis-specific rash. (21st June 2021)

• Record Type: Journal Article
• Authors: Ichimura, Yuki; Konishi, Risa; Shobo, Miwako; Inoue, Sae; Okune, Mari; Maeda, Akemi; Tanaka, Ryota; Kubota, Noriko; Matsumoto, Isao; Ishii, Akiko; Tamaoka, Akira; Shimbo, Asami; Mori, Masaaki; Morio, Tomohiro; Kishi, Takayuki; Miyamae, Takako; Tanboon, Jantima; Inoue, Michio; Nishino, Ichizo; Fujimoto, Manabu; Nomura, Toshifumi; Okiyama, Naoko
• Is Part Of: Rheumatology. Volume 61:Number 3(2022)
• Page Start: 1222
• Page End: 1227
• Publication Date: 2021-06-21
• Subjects: DM -- PM -- myositis-specific antibodies -- anti-nuclear matrix protein 2 antibody -- muscle involvement -- skin manifestation -- juvenile -- adult; Rheumatism -- Periodicals; Rheumatology -- Periodicals; 616.723005
• DOI: 10.1093/rheumatology/keab518
• Languages: English
• ISSNs: 1462-0324

Abstract

Abstract: Objectives: Myositis-specific autoantibodies (MSAs) define distinct clinical subsets of idiopathic inflammatory myopathies (IIMs). The anti-nuclear matrix protein 2 (NXP2) antibody, a MSA detected in juvenile/adult IIMs, has been reported to be associated with a high risk of subcutaneous calcinosis, subcutaneous oedema and internal malignancies. The study aimed to clarify the clinical features of anti-NXP2 antibody-positive IIMs in detail. Methods: This was a multicentre retrospective observational study on 76 anti-NXP2 antibody-positive patients. The antibody was detected via a serological assay using immunoprecipitation and western blotting. The patients were selected from 162 consecutive Japanese patients with IIMs. Results: The cohort of anti-NXP2 antibody-positive IIMs included 29 juvenile patients and 47 adult patients. Twenty-seven (35.5%) patients presented with polymyositis phenotype without dermatomyositis-specific skin manifestations (heliotrope rash or Gottron sign/papules); this was more common in the adults than children (48.9% vs 15.8%, P < 0.01). Nine (11.8%) patients had subcutaneous calcinosis, and 20 (26.3%) patients had subcutaneous oedema. In addition, the proportion of patients with muscle weakness extending to the distal limbs was high (36 patients [47.4%]) in this cohort. Adult patients had a higher prevalence of malignancy than the general population (age-standardized incidence ratio of malignancies: 22.4). Conclusion: Anti-NXP2 antibody-positive IIMs, which include dermatomyositis sine dermatitis, are characterized by atypical skin manifestations and extensive muscular involvement.