title: Anti-PM-Scl antibody in patients with systemic sclerosis.
abstract: OBJECTIVE
  To compare systemic sclerosis (SSc) patients with and without anti-PM-Scl antibody.
  
  
  METHODS
  We reviewed the medical records of 76 anti-PM-Scl antibody positive SSc patients and 2349 anti-PMScl negative SSc patients first evaluated during 1980-2004. Patients were included if they had a clinical diagnosis of SSc either alone or in overlap with another connective tissue disease. Anti-PM-Scl antibody was screened for by indirect immunofluorescence and tested by Ouchterlony double immunodiffusion.
  
  
  RESULTS
  Anti-PM-Scl antibody positive patients had a significantly higher frequency of a positive ANA with nucleolar staining (87% vs. 32%, p<0.0001) and were younger at both symptom onset (p=0.004) and first physician diagnosis of SSc (p<0.001). They were classified more often as having overlap with another connective tissue disease, particularly polymyositis-dermatomyositis, and more frequently had limited cutaneous involvement (72% vs. 52%, p=0.001). Maximal skin thickening was less in anti-PM-Scl antibody patients (mean modified Rodnan total skin score 6.0±6.3 vs. 15.9±14.2, p<0.001). Anti-PM-Scl antibody positive patients less frequently had peripheral vascular (91% vs. 98%, p=0.0002) and gastrointestinal (52% vs. 79%, p=0.0001) disease. Lung involvement overall had a similar distribution between both groups. However, radiographic evidence of pulmonary fibrosis was more frequent in anti-PM-Scl antibody positive patients (50% vs. 37%, p=0.05) and pulmonary arterial hypertension was less often detected (5% vs. 15%, p<0.04). Skeletal muscle involvement (51% vs. 14%, p<0.0001) and subcutaneous calcinosis (p<0.003) were both significantly more often observed in anti-PM-Scl antibody positive patients. Joint, heart, and kidney involvement were similar in both groups. Overall survival was significantly better for anti-PM-Scl antibody positive patients (10 year cumulative survival rate 91% vs. 65%, p=0.0002). After adjustment for age, sex and limited vs. diffuse cutaneous involvement, patients with anti-PM-Scl antibody were significantly less likely to die (HR=0.32, 95% CI, [0.14, 0.72] p=0.006).
  
  
  CONCLUSIONS
  SSc patients with anti-PM-Scl antibody are younger and significantly more often have limited cutaneous involvement, skeletal muscle disease, pulmonary fibrosis and calcinosis compared to anti-PM-Scl antibody negative SSc patients. Ten-year cumulative survival is significantly better in anti-PM-Scl antibody positive SSc patients.
authors.affiliation: Drexel University College of Medicine, PA, USA. koschik@gmail.com
authors.forename: Robert W
authors.initials: RW
authors.lastname: Koschik
authors.forename: Noreen
authors.initials: N
authors.lastname: Fertig
authors.forename: Mary R
authors.initials: MR
authors.lastname: Lucas
authors.forename: Robyn T
authors.initials: RT
authors.lastname: Domsic
authors.forename: Thomas A
authors.initials: TA
authors.lastname: Medsger
mesh_terms: D000328:Adult; D000367:Age Factors; D001323:Autoantibodies / Q000097:blood*; D018450:Disease Progression; D005095:Exoribonucleases / Q000276:immunology*; D063326:Exosome Multienzyme Ribonuclease Complex; D005260:Female; D005455:Fluorescent Antibody Technique; D006801:Humans; D005779:Immunodiffusion; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D009687:Nuclear Proteins / Q000276:immunology*; D010414:Pennsylvania; D011379:Prognosis; D016016:Proportional Hazards Models; D018570:Risk Assessment; D012307:Risk Factors; D012595:Scleroderma, Systemic / Q000097:blood / Q000150:complications / Q000175:diagnosis / Q000276:immunology* / Q000401:mortality; D012720:Severity of Illness Index; D013997:Time Factors; D055815:Young Adult
chemical_list: D001323:Autoantibodies; D009687:Nuclear Proteins; D005095:Exoribonucleases; D063326:Exosome Multienzyme Ribonuclease Complex; C077044:EXOSC10 protein, human