Sputum proteomics in inflammatory and suppurative respiratory diseases.
BACKGROUND
Markers of inflammatory activity are important for assessment and management of many respiratory diseases. Markers that are currently unrecognized may be more valuable than those presently believed to be useful.


OBJECTIVE
To identify potential biomarkers of suppurative and inflammatory lung disease in induced sputum samples.


METHODS
Induced sputum was collected from 20 healthy control subjects, 24 patients with asthma, 24 with chronic obstructive pulmonary disease, 28 with cystic fibrosis (CF), and 19 with bronchiectasis. Twelve patients with CF had sputum sampled before and after antibiotic therapy for an infective exacerbation. The fluid phase of induced sputum was analyzed by surface-enhanced laser desorption/ionization time-of-flight (SELDI-TOF) mass spectroscopy on three protein array surfaces. Some protein markers were selected for identification, and relevant ELISA assays sought. For 12 patients with CF, both SELDI-TOF and ELISA monitored changes in inflammatory responses during infective exacerbations.


RESULTS
SELDI-TOF identified potential biomarkers that differentiated each of the disease groups from healthy control subjects: at a significance of P < 0.01, there were 105 for asthma, 113 for chronic obstructive pulmonary disease, 381 for CF, and 377 for bronchiectasis. Peaks selected for protein identification yielded calgranulin A, calgranulin B, calgranulin C, Clara cell secretory protein, lysosyme c, proline rich salivary peptide, cystatin s, and hemoglobin alpha. On treatment of an infective CF exacerbation, SELDI-TOF determined falls in levels of calgranulin A and calgranulin B that were mirrored by ELISA-measured falls in calprotectin (heterodimer of calgranulins A and B).


CONCLUSIONS
Proteomic screening of sputum yields potential biomarkers of inflammation. The early development of a clinically relevant assay from such data is demonstrated.
School of Molecular and Clinical Medicine, University of Edinburgh, Western General Hospital, Edinburgh, United Kingdom.
Robert D
RD
Gray
Gordon
G
MacGregor
Donald
D
Noble
Margaret
M
Imrie
Maria
M
Dewar
A Christopher
AC
Boyd
J Alastair
JA
Innes
David J
DJ
Porteous
Andrew P
AP
Greening
D000328:Adult; D000368:Aged; D001249:Asthma / Q000175:diagnosis; D015415:Biomarkers / Q000378:metabolism*; D001982:Bronchial Diseases / Q000175:diagnosis*; D001987:Bronchiectasis / Q000175:diagnosis; D016022:Case-Control Studies; D003550:Cystic Fibrosis / Q000175:diagnosis; D005260:Female; D006801:Humans; D007249:Inflammation; D039841:Leukocyte L1 Antigen Complex / Q000378:metabolism; D008137:Longitudinal Studies; D008171:Lung Diseases / Q000175:diagnosis*; D008297:Male; D008875:Middle Aged; D010449:Peptide Mapping / Q000379:methods; D040901:Proteomics; D029424:Pulmonary Disease, Chronic Obstructive / Q000175:diagnosis; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013183:Sputum / Q000737:chemistry*; D013492:Suppuration
D015415:Biomarkers; D039841:Leukocyte L1 Antigen Complex