title: Protein microarray analysis in patients with asthma: elevation of the chemokine PARC/CCL18 in sputum.
abstract: BACKGROUND
  Microarray technology offers a new opportunity to gain insight into global gene and protein expression profiles in asthma. To identify novel factors produced in the asthmatic airway, we analyzed sputum samples by using a membrane-based human cytokine microarray technology in patients with bronchial asthma (BA).
  
  
  METHODS
  Induced sputum was obtained from 28 BA subjects, 20 nonasthmatic atopic control (AC) subjects, and 38 nonasthmatic nonatopic normal control (NC) subjects. The microarray samples of subjects were randomly selected from nine BA subjects, three AC subjects, and six NC subjects. Sputum supernatants were analyzed using a custom human cytokine array (RayBio Custom Human Cytokine Array; RayBiotech; Norcross, GA) designed to analyze 79 specific cytokines simultaneously. The levels of growth-regulated oncogene (GRO)-alpha, eotaxin-2, and pulmonary and activation-regulated chemokine (PARC)/CCL18 were measured by sandwich enzyme-linked immunosorbent assays (ELISAs), and eosinophil-derived neurotoxin (EDN) was measured by radioimmunoassay.
  
  
  RESULTS
  By microarray, the signal intensities for GRO-alpha, eotaxin-2, and PARC were significantly higher in BA subjects than in AC and NC subjects (p = 0.036, p = 0.042, and p = 0.033, respectively). By ELISA, the sputum PARC protein levels were significantly higher in BA subjects than in AC and NC subjects (p < 0.0001). Furthermore, PARC levels correlated significantly with sputum eosinophil percentages (r = 0.570, p < 0.0001) and the levels of EDN (r = 0.633, p < 0.0001), the regulated upon activation, normal T cell expressed and secreted cytokine (r = 0.440, p < 0.001), interleukin-4 (r = 0.415, p < 0.01), and interferon-gamma (r = 0.491, p < 0.001).
  
  
  CONCLUSIONS
  By a nonbiased screening approach, a chemokine, PARC, is elevated in sputum specimens from patients with asthma. PARC may play important roles in development of airway eosinophilic inflammation in asthma.
authors.affiliation: Department of Pediatrics, Asthma & Allergy Center, Inje University Sanggye Paik Hospital, Seoul, Korea.
authors.forename: Hyo-Bin
authors.initials: HB
authors.lastname: Kim
authors.affiliation: Department of Pediatrics, Asthma & Allergy Center, Inje University Sanggye Paik Hospital, Seoul, Korea.
authors.forename: Chang-Keun
authors.initials: CK
authors.lastname: Kim
authors.affiliation: Department of Immunology, Allergic Diseases Research Laboratory, Mayo Clinic and Foundation, Rochester, MN.
authors.forename: Koji
authors.initials: K
authors.lastname: Iijima
authors.affiliation: Department of Immunology, Allergic Diseases Research Laboratory, Mayo Clinic and Foundation, Rochester, MN.
authors.forename: Takao
authors.initials: T
authors.lastname: Kobayashi
authors.affiliation: Department of Immunology, Allergic Diseases Research Laboratory, Mayo Clinic and Foundation, Rochester, MN. Electronic address: kita.hirohito@mayo.edu.
authors.forename: Hirohito
authors.initials: H
authors.lastname: Kita
mesh_terms: D001249:Asthma / Q000378:metabolism*; D015415:Biomarkers / Q000032:analysis; D016022:Case-Control Studies; D054423:Chemokine CCL24 / Q000032:analysis / Q000378:metabolism*; D018925:Chemokines / Q000032:analysis / Q000378:metabolism; D019742:Chemokines, CC / Q000032:analysis / Q000378:metabolism*; D015331:Cohort Studies; D027101:DNA Topoisomerase IV / Q000032:analysis / Q000378:metabolism*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D006801:Humans; D008297:Male; D011336:Probability; D040081:Protein Array Analysis; D011863:Radioimmunoassay; D012016:Reference Values; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D013183:Sputum / Q000737:chemistry / Q000378:metabolism*; D018709:Statistics, Nonparametric
chemical_list: D015415:Biomarkers; C111792:CCL18 protein, human; D054423:Chemokine CCL24; D018925:Chemokines; D019742:Chemokines, CC; D027101:DNA Topoisomerase IV