title: Increased circulating fibrocytes are associated with higher reticulocyte percent in children with sickle cell anemia.
abstract: BACKGROUND
  Interstitial lung disease is common in patients with sickle cell anemia (SCA). Fibrocytes are circulating cells implicated in the pathogenesis of pulmonary fibrosis and airway remodeling in asthma. In this study, we tested the hypotheses that fibrocyte levels are: (1) increased in children with SCA compared to healthy controls, and (2) associated with pulmonary disease.
  
  
  METHODS
  Cross-sectional cohort study of children with SCA who participated in the Sleep Asthma Cohort Study.
  
  
  RESULTS
  Fibrocyte levels were obtained from 45 children with SCA and 24 controls. Mean age of SCA cases was 14 years and 53% were female. In children with SCA, levels of circulating fibrocytes were greater than controls (P < 0.01). The fibrocytes expressed a hierarchy of chemokine receptors, with CXCR4 expressed on the majority of cells and CCR2 and CCR7 expressed on a smaller subset. Almost half of fibrocytes demonstrated α-smooth muscle actin activation. Increased fibrocyte levels were associated with a higher reticulocyte count (P = 0.03) and older age (P = 0.048) in children with SCA. However, children with increased levels of fibrocytes were not more likely to have asthma or lower percent predicted forced expiratory volume in 1 sec/forced vital capacity (FEV1 /FVC) or FEV1 than those with lower fibrocyte levels.
  
  
  CONCLUSIONS
  Higher levels of fibrocytes in children with SCA compared to controls may be due to hemolysis. Longitudinal studies may be able to better assess the relationship between fibrocyte level and pulmonary dysfunction.
authors.affiliation: Medical Sciences Institute, BloodCenter of Wisconsin, Milwaukee, Wisconsin.|Department of Pathology, Medical College of Wisconsin, Milwaukee, Wisconsin.
authors.forename: Matthew S
authors.initials: MS
authors.lastname: Karafin
authors.affiliation: Department of Medicine, Medical College of Wisconsin, Milwaukee, Wisconsin.
authors.forename: Shibani
authors.initials: S
authors.lastname: Dogra
authors.affiliation: Independent Statistician, Chicago, Illinois.
authors.forename: Mark
authors.initials: M
authors.lastname: Rodeghier
authors.affiliation: Department of Medicine, University of Virginia, Charlottesville, Virginia.
authors.forename: Marie
authors.initials: M
authors.lastname: Burdick
authors.affiliation: Department of Medicine, University of Virginia, Charlottesville, Virginia.
authors.forename: Borna
authors.initials: B
authors.lastname: Mehrad
authors.affiliation: Department of Medicine, University of Virginia, Charlottesville, Virginia.
authors.forename: C Edward
authors.initials: CE
authors.lastname: Rose
authors.affiliation: Novartis Institutes for Biomedical Research, Cambridge, Massachusetts.
authors.forename: Robert M
authors.initials: RM
authors.lastname: Strieter
authors.affiliation: University School of Medicine and Monroe Carell Jr Children's Hospital, Nashville, Tennessee.
authors.forename: Michael R
authors.initials: MR
authors.lastname: DeBaun
authors.affiliation: Department of Pediatrics, Washington University School of Medicine, St. Louis, Missouri.
authors.forename: Robert C
authors.initials: RC
authors.lastname: Strunk
authors.affiliation: Medical Sciences Institute, BloodCenter of Wisconsin, Milwaukee, Wisconsin.|Department of Medicine, Medical College of Wisconsin, Milwaukee, Wisconsin.
authors.forename: Joshua J
authors.initials: JJ
authors.lastname: Field
mesh_terms: D000293:Adolescent; D000755:Anemia, Sickle Cell / Q000097:blood* / Q000150:complications / Q000503:physiopathology; D001249:Asthma / Q000097:blood* / Q000150:complications / Q000503:physiopathology; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D017563:Lung Diseases, Interstitial / Q000097:blood* / Q000150:complications / Q000503:physiopathology; D008297:Male; D011658:Pulmonary Fibrosis / Q000097:blood* / Q000150:complications / Q000503:physiopathology; D012156:Reticulocytes; D055815:Young Adult
keywords: asthma; fibrocytes; sickle cell anemia