title: Periostin is a systemic biomarker of eosinophilic airway inflammation in asthmatic patients.
abstract: BACKGROUND
  Eosinophilic airway inflammation is heterogeneous in asthmatic patients. We recently described a distinct subtype of asthma defined by the expression of genes inducible by T(H)2 cytokines in bronchial epithelium. This gene signature, which includes periostin, is present in approximately half of asthmatic patients and correlates with eosinophilic airway inflammation. However, identification of this subtype depends on invasive airway sampling, and hence noninvasive biomarkers of this phenotype are desirable.
  
  
  OBJECTIVE
  We sought to identify systemic biomarkers of eosinophilic airway inflammation in asthmatic patients.
  
  
  METHODS
  We measured fraction of exhaled nitric oxide (Feno), peripheral blood eosinophil, periostin, YKL-40, and IgE levels and compared these biomarkers with airway eosinophilia in asthmatic patients.
  
  
  RESULTS
  We collected sputum, performed bronchoscopy, and matched peripheral blood samples from 67 asthmatic patients who remained symptomatic despite maximal inhaled corticosteroid treatment (mean FEV(1), 60% of predicted value; mean Asthma Control Questionnaire [ACQ] score, 2.7). Serum periostin levels are significantly increased in asthmatic patients with evidence of eosinophilic airway inflammation relative to those with minimal eosinophilic airway inflammation. A logistic regression model, including sex, age, body mass index, IgE levels, blood eosinophil numbers, Feno levels, and serum periostin levels, in 59 patients with severe asthma showed that, of these indices, the serum periostin level was the single best predictor of airway eosinophilia (P = .007).
  
  
  CONCLUSIONS
  Periostin is a systemic biomarker of airway eosinophilia in asthmatic patients and has potential utility in patient selection for emerging asthma therapeutics targeting T(H)2 inflammation.
authors.affiliation: Immunology, Tissue Growth, and Repair (ITGR) Biomarker Discovery, Genentech, Inc, South San Francisco, CA 94080, USA.
authors.forename: Guiquan
authors.initials: G
authors.lastname: Jia
authors.forename: Richard W
authors.initials: RW
authors.lastname: Erickson
authors.forename: David F
authors.initials: DF
authors.lastname: Choy
authors.forename: Sofia
authors.initials: S
authors.lastname: Mosesova
authors.forename: Lawren C
authors.initials: LC
authors.lastname: Wu
authors.forename: Owen D
authors.initials: OD
authors.lastname: Solberg
authors.forename: Aarti
authors.initials: A
authors.lastname: Shikotra
authors.forename: Richard
authors.initials: R
authors.lastname: Carter
authors.forename: Séverine
authors.initials: S
authors.lastname: Audusseau
authors.forename: Qutayba
authors.initials: Q
authors.lastname: Hamid
authors.forename: Peter
authors.initials: P
authors.lastname: Bradding
authors.forename: John V
authors.initials: JV
authors.lastname: Fahy
authors.forename: Prescott G
authors.initials: PG
authors.lastname: Woodruff
authors.forename: Jeffrey M
authors.initials: JM
authors.lastname: Harris
authors.forename: Joseph R
authors.initials: JR
authors.lastname: Arron
mesh_terms: D054392:Adipokines / Q000097:blood; D000328:Adult; D001249:Asthma / Q000097:blood* / Q000188:drug therapy; D015415:Biomarkers; D001944:Breath Tests; D015815:Cell Adhesion Molecules / Q000097:blood*; D000071451:Chitinase-3-Like Protein 1; D004802:Eosinophilia / Q000097:blood / Q000175:diagnosis*; D004804:Eosinophils / Q000502:physiology; D005260:Female; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood; D007249:Inflammation / Q000097:blood / Q000175:diagnosis*; D018793:Interleukin-13 / Q000032:analysis / Q000502:physiology; D037102:Lectins / Q000097:blood; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009569:Nitric Oxide / Q000032:analysis
chemical_list: D054392:Adipokines; D015415:Biomarkers; C084533:CHI3L1 protein, human; D015815:Cell Adhesion Molecules; D000071451:Chitinase-3-Like Protein 1; D018793:Interleukin-13; D037102:Lectins; C512835:POSTN protein, human; D009569:Nitric Oxide; D007073:Immunoglobulin E