Anti-MJ/NXP-2 autoantibody specificity in a cohort of adult Italian patients with polymyositis/dermatomyositis

Angela Ceribelli, Micaela Fredi, Mara Taraborelli, Ilaria Cavazzana, Franco Franceschini, Marzia Quinzanini, Angela Tincani, Steven J. Ross, Jason Y F Chan, Brad A. Pauley, Edward K L Chan, Minoru Satoh

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Abstract

Introduction: Autoantibodies in patients with polymyositis/dermatomyositis (PM/DM) are associated with unique subsets, clinical course and outcome. Anti-MJ antibodies, which recognize the nuclear protein NXP-2/MORC3, are reported in ~25% of juvenile DM. Prevalence and clinical significance of anti-MJ antibodies in adult Italian PM/DM patients were studied.Methods: Sera from 58 consecutive adult Italian PM/DM patients were analyzed by immunoprecipitation of 35S-labeled K562 cells extract, ELISA (anti-MJ, Jo-1), Western blot and indirect immunofluorescence. Clinical associations were analyzed using information from medical charts.Results: Anti-MJ antibodies were the most prevalent specificity (17%) found mainly in DM (30%, 8 cases) vs 8% of PM (2 cases, P = 0.02). Comparing 10 anti-MJ (+) vs 48 anti-MJ (-) cases, DM was more common (P = 0.03), and age at onset was younger in anti-MJ (+) (P = 0.0006). In anti-MJ (+), heliotrope rash (P = 0.01) and calcinosis (P = 0.09) were more frequent. None of them had heart or lung involvement, or malignancy. Myopathy in anti-MJ (+) patients responded well to therapy and none of them had elevated CPK at last visit (0% vs 25% in anti-MJ (-)). Only 60% of anti-MJ (+) showed immunofluorescent nuclear dots staining, despite PML localization of NXP-2/MORC3.Conclusions: Anti-MJ antibodies are the most frequent specificity in our cohort of adult Italian PM/DM. Anti-MJ (+) were associated with young onset DM, calcinosis, no internal organ involvement and good response of myopathy to therapy. Anti-MJ reported in juvenile DM is also found in adult PM/DM, and could be a new useful biomarker.

Original languageEnglish
Article numberR97
JournalArthritis Research and Therapy
Volume14
Issue number2
DOIs
Publication statusPublished - Apr 30 2012

ASJC Scopus subject areas

  • Rheumatology
  • Immunology
  • Immunology and Allergy
  • Medicine(all)

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    Ceribelli, A., Fredi, M., Taraborelli, M., Cavazzana, I., Franceschini, F., Quinzanini, M., Tincani, A., Ross, S. J., Chan, J. Y. F., Pauley, B. A., Chan, E. K. L., & Satoh, M. (2012). Anti-MJ/NXP-2 autoantibody specificity in a cohort of adult Italian patients with polymyositis/dermatomyositis. Arthritis Research and Therapy, 14(2), [R97]. https://doi.org/10.1186/ar3822