Soluble interleukin-5 receptor alpha is increased in acute exacerbation of chronic obstructive pulmonary disease.
BACKGROUND
During chronic obstructive pulmonary disease (COPD) exacerbations (AE-COPD), an influx of eosinophils into the bronchial mucosa has been described. Eosinophilic cationic protein (ECP) and soluble interleukin-5 receptor alpha (sIL5Ralpha) are secreted by eosinophils and increased in eosinophilic airway diseases.


METHODS
We studied ECP and sIL5Ralpha expression in patients with COPD compared to healthy controls and smokers and investigated a possible association to viral exacerbations of COPD. Expression of sIL5Ralpha in serum was analyzed by ELISA and ECP by the Uni-Cap system. Induced sputum from patients with COPD was analyzed for six different respiratory viruses by nested PCR.


RESULTS
ECP and sIL5Ralpha were significantly elevated in AE-COPD subjects (n = 54) compared to healthy controls (n = 11, p = 0.018). Furthermore, there was a significant increase in sIL5Ralpha, but not in ECP, in 30 patients with virus-associated AE-COPD compared to smokers without COPD (n = 16) and healthy controls. The increase in FEV(1) after resolution of the AE-COPD correlated with the decrease in sIL5Ralpha (r = 0.269, p = 0.034).


CONCLUSIONS
sIL5Ralpha is increased in AE-COPD and not affected by smoking like ECP. sIL5Ralpha is increased in patients with virus-associated AE-COPD compared to smokers and controls. Concentrations of sIL5Ralpha mirror changes in the clinical status and lung function. These data support the involvement of eosinophils in acute exacerbations of COPD.
Department of Internal Medicine III, Pneumology, Allergology and Sleep Medicine, University Hospital Bergmannsheil, DE-44789 Bochum, Germany. gernot.rohde@ruhr-uni-bochum.de
Gernot
G
Rohde
Philippe
P
Gevaert
Gabriele
G
Holtappels
Lucie
L
Fransen
Irmgard
I
Borg
Almut
A
Wiethege
Umut
U
Arinir
Jan
J
Tavernier
Gerhard
G
Schultze-Werninghaus
Claus
C
Bachert
D001798:Blood Proteins / Q000276:immunology; D047091:Eosinophil Granule Proteins; D006801:Humans; D053666:Interleukin-5 Receptor alpha Subunit; D029424:Pulmonary Disease, Chronic Obstructive / Q000097:blood / Q000276:immunology* / Q000821:virology; D018123:Receptors, Interleukin / Q000097:blood* / Q000276:immunology; D012008:Recurrence; D012260:Ribonucleases / Q000097:blood / Q000276:immunology; D012907:Smoking / Q000276:immunology; D013183:Sputum / Q000821:virology; D014777:Virus Diseases / Q000276:immunology
D001798:Blood Proteins; D047091:Eosinophil Granule Proteins; C485918:IL5RA protein, human; D053666:Interleukin-5 Receptor alpha Subunit; D018123:Receptors, Interleukin; D012260:Ribonucleases