Myopathy associated with anti-signal recognition particle antibodies with pulmonary involvement and response to rituximab

Rheumatol Int. 2022 Jul;42(7):1265-1269. doi: 10.1007/s00296-021-04904-5. Epub 2021 Jun 4.

Abstract

The authors present the case of a 76-year-old female patient with progressive decrease in proximal muscle strength, fatigue, dyspnea, diffuse hand edema and painful triphasic Raynaud's phenomenon. Anti-SRP and anti-SSA antibodies were detected, muscle biopsy revealed changes consistent with necrotizing myopathy and capillaroscopy had findings compatible with systemic sclerosis. High-resolution chest computed tomography revealed interstitial lung disease with a non-specific interstitial pneumonia pattern. Lung function tests demonstrated a forced vital capacity 93% and a diffusing capacity for carbon monoxide of 65% predicted. After multidisciplinary discussion, she was diagnosed with immune-mediated necrotizing myopathy/systemic sclerosis overlap syndrome with pulmonary involvement. Initially, dual immunomodulation therapy with high-dose steroids and intravenous immunoglobulin was started, but after 4 weeks, the patient had clinical and analytical deterioration. At this time, she was started on rituximab, with an excellent and sustained response at both muscle and lung, sustained after 12 months.

Keywords: Autoantibodies; Interstitial lung disease; Myositis; Signal recognition particle.

Publication types

  • Case Reports
  • Review

MeSH terms

  • Aged
  • Autoantibodies
  • Autoimmune Diseases* / complications
  • Female
  • Humans
  • Muscular Diseases* / complications
  • Myositis*
  • Rituximab / therapeutic use
  • Scleroderma, Systemic* / complications
  • Signal Recognition Particle

Substances

  • Autoantibodies
  • Signal Recognition Particle
  • Rituximab