title: KL-6 as a novel serum marker for interstitial pneumonia associated with collagen diseases.
abstract: OBJECTIVE
  To investigate the diagnostic value of the serum concentrations of KL-6, a mucinous glycoprotein expressed on type II pneumocytes, for interstitial pneumonia (IP) in various collagen diseases.
  
  
  METHODS
  Serum KL-6 levels were measured by ELISA.
  
  
  RESULTS
  The mean values and the positive rates of serum KL-6 levels for patients with rheumatoid arthritis, systemic sclerosis, or polymyositis/dermatomyositis with IP were significantly higher than those without IP. Sensitivity, specificity, positive and negative predictive values of serum KL-6 level for IP associated with collagen diseases were 60.7, 98.9, 97.4, and 77.1%, respectively. The mean serum KL-6 level of patients with active IP was significantly (p = 0.0001) higher than that of patients with inactive IP. Serum KL-6 levels increased with the deterioration of IP, while the successful treatment of IP resulted in a significant decrease of these levels.
  
  
  CONCLUSIONS
  Serum KL-6 concentration levels are a useful marker for diagnosis and evaluation of the disease activity of IP associated with collagen diseases.
authors.affiliation: Institute of Rheumatology, Tokyo Women's Medical University, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Nakajima
authors.forename: M
authors.initials: M
authors.lastname: Harigai
authors.forename: M
authors.initials: M
authors.lastname: Hara
authors.forename: M
authors.initials: M
authors.lastname: Hakoda
authors.forename: H
authors.initials: H
authors.lastname: Tokuda
authors.forename: F
authors.initials: F
authors.lastname: Sakai
authors.forename: N
authors.initials: N
authors.lastname: Kamatani
authors.forename: S
authors.initials: S
authors.lastname: Kashiwazaki
mesh_terms: D000328:Adult; D000941:Antigens / Q000097:blood*; D000951:Antigens, Neoplasm; D015415:Biomarkers / Q000097:blood; D002097:C-Reactive Protein / Q000032:analysis; D003095:Collagen Diseases / Q000097:blood* / Q000150:complications / Q000175:diagnosis / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006023:Glycoproteins / Q000097:blood*; D006801:Humans; D007770:L-Lactate Dehydrogenase / Q000097:blood; D017563:Lung Diseases, Interstitial / Q000097:blood* / Q000150:complications / Q000175:diagnosis / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D018396:Mucin-1; D009077:Mucins; D011237:Predictive Value of Tests; D011379:Prognosis
chemical_list: D000941:Antigens; D000951:Antigens, Neoplasm; D015415:Biomarkers; D006023:Glycoproteins; C060192:MUC1 protein, human; D018396:Mucin-1; D009077:Mucins; D002097:C-Reactive Protein; D007770:L-Lactate Dehydrogenase