Calcinosis in juvenile dermatomyositis is influenced by both anti-NXP2 autoantibody status and age at disease onset

Rheumatology (Oxford). 2014 Dec;53(12):2204-8. doi: 10.1093/rheumatology/keu259. Epub 2014 Jul 1.


Objective: Calcinosis is a major cause of morbidity in JDM and has previously been linked to anti-NXP2 autoantibodies, younger age at disease onset and more persistent disease activity. This study aimed to investigate the clinical associations of anti-NXP2 autoantibodies in patients with JDM stratified by age at disease onset.

Methods: A total of 285 patients with samples and clinical data were recruited via the UK Juvenile Dermatomyositis Cohort and Biomarker Study. The presence of anti-NXP2 was determined by both immunoprecipitation and ELISA. Logistic regression analysis was performed to assess the age-dependent relationship between anti-NXP2 and the development of calcinosis and disease activity measures.

Results: We identified anti-NXP2 autoantibodies in 56 patients (20%). While in all patients younger age at disease onset was associated with an increased risk of calcinosis and this relationship was nearly linear, anti-NXP2 autoantibodies substantially increased the risk of calcinosis across all ages (P = 0.025) and were detectable prior to calcinosis development. Children with anti-NXP2 autoantibodies had a greater degree of weakness (median lowest ever Childhood Myositis Assessment Score 29.6 vs 42) and were less likely to be in remission at 2 years post-diagnosis. No difference in disease activity was seen 4 years post-diagnosis.

Conclusion: Children diagnosed at a young age have a high risk of calcinosis regardless of autoantibody status. However, the presence of anti-NXP2 autoantibodies substantially increases the risk of calcinosis across all ages and is associated with disease severity.

Keywords: age; autoantibody; calcinosis; juvenile dermatomyositis.

Publication types

  • Multicenter Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine Triphosphatases / immunology*
  • Age of Onset
  • Autoantibodies / blood*
  • Biomarkers / blood
  • Calcinosis / etiology*
  • Calcinosis / immunology
  • Child
  • Child, Preschool
  • Cohort Studies
  • DNA-Binding Proteins / immunology*
  • Dermatomyositis / complications*
  • Dermatomyositis / immunology
  • Female
  • Humans
  • Male
  • Muscle Weakness / etiology
  • Muscle Weakness / immunology
  • Prognosis
  • Risk Assessment / methods
  • Severity of Illness Index


  • Autoantibodies
  • Biomarkers
  • DNA-Binding Proteins
  • Adenosine Triphosphatases
  • MORC3 protein, human

Supplementary concepts

  • Amyopathic dermatomyositis