title: Airway eosinophilia and expression of interleukin-5 protein in asthma and in exacerbations of chronic bronchitis.
abstract: BACKGROUND
  An increased number of eosinophils in the bronchial mucosa has been demonstrated both in asthma and in exacerbations of chronic bronchitis.
  
  
  OBJECTIVE
  To investigate whether the airway eosinophilia present in asthma and in chronic bronchitis during exacerbations is associated with interleukin (IL)-5 protein expression in the bronchial mucosa.
  
  
  METHODS
  We obtained bronchial biopsies in 18 subjects with asthma (four intrinsic, seven extrinsic and seven occupational) and in 11 subjects with chronic bronchitis examined during an exacerbation. The findings were compared with those of bronchial biopsies from 10 subjects with chronic bronchitis examined under baseline conditions and from seven normal subjects, taken as controls. By immunohistochemistry, we assessed the expression of IL-5 protein and the number of eosinophils (EG2), mast cells (tryptase), and T-lymphocytes (CD3) in the submucosa.
  
  
  RESULTS
  As compared with controls, the number of eosinophils was increased to a similar degree in both asthma (P < 0.001) and in exacerbations of chronic bronchitis (P < 0.001), whereas the number of IL-5 immunopositive cells was increased significantly only in asthma (P < 0.01). No differences were observed in the number of mast cells and T-lymphocytes between the four groups of subjects examined.
  
  
  CONCLUSIONS
  This study shows that the degree of airway eosinophilia is similar in asthma and in exacerbations of chronic bronchitis, but only in asthma is it associated with an increased expression of IL-5 protein in the bronchial mucosa.
authors.affiliation: Institute of Occupational Medicine, University of Padova, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Saetta
authors.forename: A
authors.initials: A
authors.lastname: Di Stefano
authors.forename: P
authors.initials: P
authors.lastname: Maestrelli
authors.forename: G
authors.initials: G
authors.lastname: Turato
authors.forename: C E
authors.initials: CE
authors.lastname: Mapp
authors.forename: M
authors.initials: M
authors.lastname: Pieno
authors.forename: G
authors.initials: G
authors.lastname: Zanguochi
authors.forename: G
authors.initials: G
authors.lastname: Del Prete
authors.forename: L M
authors.initials: LM
authors.lastname: Fabbri
mesh_terms: D000328:Adult; D000368:Aged; D001249:Asthma / Q000378:metabolism* / Q000473:pathology / Q000503:physiopathology; D001706:Biopsy; D001991:Bronchitis / Q000378:metabolism* / Q000473:pathology / Q000503:physiopathology; D001999:Bronchoscopy; D002908:Chronic Disease; D004802:Eosinophilia / Q000378:metabolism* / Q000473:pathology; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D007150:Immunohistochemistry; D015848:Interleukin-5 / Q000378:metabolism*; D008297:Male; D008875:Middle Aged
chemical_list: D015848:Interleukin-5