Protein microarray analysis in patients with asthma: elevation of the chemokine PARC/CCL18 in sputum

Chest. 2009 Feb;135(2):295-302. doi: 10.1378/chest.08-0962. Epub 2008 Nov 18.


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.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Asthma / metabolism*
  • Biomarkers / analysis
  • Case-Control Studies
  • Chemokine CCL24 / analysis
  • Chemokine CCL24 / metabolism*
  • Chemokines / analysis
  • Chemokines / metabolism
  • Chemokines, CC / analysis
  • Chemokines, CC / metabolism*
  • Cohort Studies
  • DNA Topoisomerase IV / analysis
  • DNA Topoisomerase IV / metabolism*
  • Enzyme-Linked Immunosorbent Assay
  • Female
  • Humans
  • Male
  • Probability
  • Protein Array Analysis
  • Radioimmunoassay
  • Reference Values
  • Sensitivity and Specificity
  • Severity of Illness Index
  • Sputum / chemistry
  • Sputum / metabolism*
  • Statistics, Nonparametric


  • Biomarkers
  • CCL18 protein, human
  • Chemokine CCL24
  • Chemokines
  • Chemokines, CC
  • DNA Topoisomerase IV