title: Correlation between circulating fibrocytes, and activity and progression of interstitial lung diseases.
abstract: OBJECTIVE
  Interstitial lung diseases (ILD) are characterized by progressive interstitial pulmonary fibrosis and a decline in lung function. Fibrocytes are bone marrow-derived mesenchymal progenitor cells that may play a role in the pathogenesis of pulmonary fibrosis. Circulating fibrocyte numbers have been correlated with the prognosis of patients with idiopathic pulmonary fibrosis. The aim of the present study was to evaluate the relationship between circulating fibrocytes, and parameters of disease activity and progression in several groups of patients with ILD.
  
  
  METHODS
  The study population comprised 41 patients with ILD and seven healthy control subjects. Circulating CD45(+) collagen-I(+) fibrocytes were evaluated by flow cytometry.
  
  
  RESULTS
  The number of circulating fibrocytes was significantly increased in all patients with ILD and particularly in patients with idiopathic interstitial pneumonitis and interstitial pneumonitis associated with collagen vascular disease as compared with healthy control subjects. The numbers of circulating fibrocytes were significantly correlated with pulmonary function test parameters and with serum levels of sialylated carbohydrate antigen, a marker of disease activity. Temporal changes in circulating fibrocyte numbers were evaluated in two patients, and the results suggested that these changes correlated with the activity of ILD.
  
  
  CONCLUSIONS
  The results from this study provide further evidence for the role of circulating fibrocytes in fibrotic lung diseases.
authors.affiliation: Divisions of Pulmonary and Critical Care Medicine, Mie University School of Medicine, Mie Chuo Medical Center, Tsu, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Fujiwara
authors.forename: Hiroyasu
authors.initials: H
authors.lastname: Kobayashi
authors.forename: Masahiro
authors.initials: M
authors.lastname: Masuya
authors.forename: Mitsuko
authors.initials: M
authors.lastname: Maruyama
authors.forename: Shiho
authors.initials: S
authors.lastname: Nakamura
authors.forename: Hidenori
authors.initials: H
authors.lastname: Ibata
authors.forename: Hajime
authors.initials: H
authors.lastname: Fujimoto
authors.forename: Masahiro
authors.initials: M
authors.lastname: Ohnishi
authors.forename: Masahito
authors.initials: M
authors.lastname: Urawa
authors.forename: Masahiro
authors.initials: M
authors.lastname: Naito
authors.forename: Takehiro
authors.initials: T
authors.lastname: Takagi
authors.forename: Tetsu
authors.initials: T
authors.lastname: Kobayashi
authors.forename: Esteban C
authors.initials: EC
authors.lastname: Gabazza
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Takei
authors.forename: Osamu
authors.initials: O
authors.lastname: Taguchi
mesh_terms: D015415:Biomarkers / Q000097:blood; D018932:Chemokine CCL2 / Q000097:blood; D054377:Chemokine CXCL12 / Q000097:blood; D018450:Disease Progression; D005260:Female; D005347:Fibroblasts / Q000473:pathology; D005434:Flow Cytometry; D006801:Humans; D017493:Leukocyte Common Antigens / Q000378:metabolism; D017563:Lung Diseases, Interstitial / Q000097:blood*; D059630:Mesenchymal Stem Cells / Q000378:metabolism*; D008875:Middle Aged; D011658:Pulmonary Fibrosis / Q000473:pathology
chemical_list: D015415:Biomarkers; D018932:Chemokine CCL2; D054377:Chemokine CXCL12; D017493:Leukocyte Common Antigens