title: Associations between anti-Ro52 antibodies and lung fibrosis in mixed connective tissue disease.
abstract: OBJECTIVE
  MCTD is a chronic, immune-mediated disorder defined by the combined presence of serum anti-RNP antibodies and distinct clinical features, including progressive lung fibrosis. The aim of the study was to evaluate the potential impact of anti-SSA (i.e. Ro52 and Ro60) and anti-SSB autoantibodies as markers for disease outcomes in MCTD.
  
  
  METHODS
  Stored serum samples from 113 patients included in the cross-sectional, nationwide Norwegian MCTD cohort were screened for the presence of anti-Ro52, anti-Ro60 and anti-SSB by a commercial line immunoassay. Correlation analyses were carried out with clinical parameters, including quantitative lung fibrosis scores by high-resolution CT. Lung fibrosis was defined by reticular pattern changes according to the Fleischner Society CT criteria for interstitial lung disease.
  
  
  RESULTS
  Anti-Ro52 antibodies were present in 29%, anti-Ro60 in 19% and anti-SSB in 6% of the MCTD sera. High-resolution CT scoring identified lung fibrosis in 38 of 113 (34%) MCTD patients. Anti-Ro52 antibodies were detected in 50% (19 of 38) of the MCTD patients with lung fibrosis and in 19% (14 of 75) without lung fibrosis (P < 0.001). The odds ratio for the presence of anti-Ro52 antibodies in lung fibrosis was 4.4 (95% CI 1.8, 10.3). Anti-Ro52 antibodies were equally frequent in patients with mild to moderate (eight of 17; 44%) and severe fibrosis (11 of 21; 52%). Anti-Ro52 was not associated with any of the other clinical parameters assessed, nor was anti-Ro60 or anti-SSB.
  
  
  CONCLUSIONS
  Our cross-sectional data suggest that anti-Ro52 antibodies may serve as a potential marker for lung fibrosis in MCTD.
authors: Rheumatology Unit, Oslo University Hospital Rikshospitalet, ragunnar@gmail.com.
authors: Ragnar
authors: R
authors: Gunnarsson
authors: Department of Immunology and Transfusion Medicine, Oslo University Hospital.
authors: Fadi
authors: F
authors: El-Hage
authors: Department of Radiology, Oslo University Hospital Rikshospitalet.
authors: Trond Mogens
authors: TM
authors: Aaløkken
authors: Institute of Clinical Medicine, University of Oslo and.
authors: Silje
authors: S
authors: Reiseter
authors: Institute of Clinical Medicine, University of Oslo and Department of Respiratory Medicine, Oslo University Hospital Rikshospitalet, Oslo, Norway.
authors: May Brit
authors: MB
authors: Lund
authors: Rheumatology Unit, Oslo University Hospital Rikshospitalet.
authors: Torhild
authors: T
authors: Garen
authors: Rheumatology Unit, Oslo University Hospital Rikshospitalet, Institute of Clinical Medicine, University of Oslo and.
authors: Øyvind
authors: Ø
authors: Molberg
mesh_terms: D000328:Adult; D000974:Antibodies, Antinuclear / Q000097:blood / Q000276:immunology*; D002908:Chronic Disease; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008947:Mixed Connective Tissue Disease / Q000097:blood / Q000150:complications / Q000276:immunology*; D011658:Pulmonary Fibrosis / Q000097:blood / Q000209:etiology / Q000276:immunology*; D012189:Retrospective Studies; D012261:Ribonucleoproteins / Q000276:immunology*; D000099207:SS-A Antigen
chemical_list: D000974:Antibodies, Antinuclear; D012261:Ribonucleoproteins; D000099207:SS-A Antigen
keywords: SSB antigen; Sjögren’s syndrome; anti-La; anti-Ro; anti-SSA/Ro52; anti-SSA/Ro60; interstitial pulmonary fibrosis; lung diseases; mixed connective tissue disease; scleroderma systemic