title: Relative α₁-anti-trypsin deficiency in systemic sclerosis.
abstract: OBJECTIVE
  Neutrophil elastase is secreted by neutrophils during activation and circulates in the plasma where it can play a role in inflammation and fibrosis. This study examines the role of neutrophil elastase in SSc, a systemic CTD that is typified by vascular dysfunction, tissue fibrosis and inflammation.
  
  
  METHODS
  Serum neutrophil elastase and α₁-anti-trypsin concentrations were assessed in SSc patients and healthy controls by ELISA. Serum neutrophil elastase activity was assessed by the elastase-dependent conversion of methoxy-succinyl-alanyl-alanyl-prolyl-valyl-p-nitroanilide to p-nitroanilide using a colourimetric assay. Elastase concentration and activity were correlated with clinical disease features.
  
  
  RESULTS
  Serum neutrophil elastase concentration and activity were equivalent in patients and controls; however, in SSc serum, there was an increase in elastase activity for each unit of elastase concentration (P = 0.03). This was due to a decrease in serum α₁-anti-trypsin concentrations (P = 0.04). Serum elastase concentration (P = 0.03) and activity (P = 0.02) were significantly lower in RNP-positive patients and serum elastase concentrations were lower in ANA-positive patients (P = 0.003).
  
  
  CONCLUSIONS
  Relative deficiency in serum α₁-anti-trypsin concentrations in SSc could have important and pathogenically relevant effects since elastase has pro-inflammatory and pro-fibrotic roles. Elastase inhibitors are available in clinical practice and could represent potential therapeutic options in SSc.
authors: Department of Rheumatology, Institute of Chronic Disease and Ageing, University of Liverpool, Clinical Sciences Centre, Aintree University Hospital, Longmoor Lane, Liverpool L9 7AL, UK.
authors: Theresa C
authors: TC
authors: Barnes
authors: Andy
authors: A
authors: Cross
authors: Marina E
authors: ME
authors: Anderson
authors: Steven W
authors: SW
authors: Edwards
authors: Robert J
authors: RJ
authors: Moots
mesh_terms: D002478:Cells, Cultured; D006801:Humans; D019272:Leukocyte Elastase / Q000097:blood*; D009504:Neutrophils / Q000201:enzymology; D012595:Scleroderma, Systemic / Q000097:blood / Q000150:complications*; D000515:alpha 1-Antitrypsin / Q000097:blood; D019896:alpha 1-Antitrypsin Deficiency / Q000097:blood / Q000150:complications*
chemical_list: D000515:alpha 1-Antitrypsin; D019272:Leukocyte Elastase