Protein microarray analysis in patients with asthma: elevation of the chemokine PARC/CCL18 in sputum.
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.
Kim
Hyo-Bin
HB
Department of Pediatrics, Asthma & Allergy Center, Inje University Sanggye Paik Hospital, Seoul, Korea.
Kim
Chang-Keun
CK
Department of Pediatrics, Asthma & Allergy Center, Inje University Sanggye Paik Hospital, Seoul, Korea.
Iijima
Koji
K
Department of Immunology, Allergic Diseases Research Laboratory, Mayo Clinic and Foundation, Rochester, MN.
Kobayashi
Takao
T
Department of Immunology, Allergic Diseases Research Laboratory, Mayo Clinic and Foundation, Rochester, MN.
Kita
Hirohito
H
Department of Immunology, Allergic Diseases Research Laboratory, Mayo Clinic and Foundation, Rochester, MN. Electronic address: kita.hirohito@mayo.edu.
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
D015415:Biomarkers; C111792:CCL18 protein, human; D054423:Chemokine CCL24; D018925:Chemokines; D019742:Chemokines, CC; D027101:DNA Topoisomerase IV