title: Serum KL-6 concentrations are associated with molecular sizes and efflux behavior of KL-6/MUC1 in healthy subjects.
abstract: BACKGROUND
  Serum KL-6, a sialylated sugar chain on human MUC1, is used as a marker of interstitial lung diseases. We recently reported that efflux behavior of KL-6/MUC1 from the alveoli into the bloodstream assessed by molecular analysis differed according to genetically determined molecular sizes and influenced serum KL-6 concentrations in sarcoidosis. This study was designed to investigate associations between molecular size and efflux behavior of KL-6/MUC1, and factors contributing to serum KL-6 concentrations in healthy subjects.
  
  
  METHODS
  Western blot analysis using anti-KL-6 antibody was performed on serum obtained from 250 healthy subjects.
  
  
  RESULTS
  The efflux behavior of KL-6/MUC1 differed according to the genetically determined molecular sizes in healthy subjects. In subjects having low molecular size, there were significant associations between smoking status, aging, renal function and serum KL-6 concentrations. However, these associations were not significant in the subjects having higher molecular size and the efflux behavior of high molecular size was the only significant determinant of serum KL-6 concentrations.
  
  
  CONCLUSIONS
  This study showed an association between KL-6/MUC1 efflux based on molecular size and serum KL-6 concentrations in healthy subjects. We propose that the molecular size and efflux behavior of KL-6/MUC1 should be considered when interpreting serum KL-6 concentrations.
authors.affiliation: First Department of Medicine, Hokkaido University School of Medicine, Sapporo, Japan; Division of Laboratory and Transfusion Medicine, Hokkaido University Hospital, Sapporo, Japan.
authors.forename: Masahiko
authors.initials: M
authors.lastname: Shigemura
authors.forename: Satoshi
authors.initials: S
authors.lastname: Konno
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Nasuhara
authors.forename: Noriharu
authors.initials: N
authors.lastname: Shijubo
authors.forename: Chikara
authors.initials: C
authors.lastname: Shimizu
authors.forename: Masaharu
authors.initials: M
authors.lastname: Nishimura
mesh_terms: D000328:Adult; D000368:Aged; D000375:Aging / Q000502:physiology*; D001692:Biological Transport; D015153:Blotting, Western; D002199:Capillary Permeability / Q000502:physiology*; D005260:Female; D006801:Humans; D007668:Kidney / Q000502:physiology; D007677:Kidney Function Tests; D008297:Male; D008875:Middle Aged; D008970:Molecular Weight; D018396:Mucin-1 / Q000097:blood* / Q000737:chemistry; D012016:Reference Values; D012907:Smoking / Q000097:blood
chemical_list: C060192:MUC1 protein, human; D018396:Mucin-1
keywords: BAL; BALF; Healthy subjects; ILDs; KL-6; KL-6/MUC1 molecular size; Krebs von den Lungen-6; MUC1; Serum KL-6 concentrations; VNTR; bronchoalveolar lavage; bronchoalveolar lavage fluid; interstitial lung diseases; mucin-1; variable number of tandem repeat