Clara cell 16 protein in COPD sputum: a marker of small airways damage?
BACKGROUND
The development of chronic obstructive pulmonary disease (COPD) in smokers and their susceptibility to infections is not fully understood. Recent evidences suggest that Clara cells play a part in host defense, immunomodulatory response and airways remodelling through the production of specific factors such as Clara cell 16 (CC-16). This protein has never been related to patients' lung function tests, blood gases parameters and diseases severity.


OBJECTIVE
To evaluate a possible correlation between CC-16 expression in sputum, measured by a new methodological approach, and the degree of severity in patients with moderate and severe COPD. We also analyzed possible correlations between CC-16 and cytological sputum population, arterial blood gases and lung function.


RESULTS
We analyzed 20 patients, mean age 72.95, classified on the basis of the global initiative for chronic obstructive lung disease guidelines (GOLD 2006). The samples were processed for cytological analysis and CC-16 levels were assessed by Western blot. We found lower levels of CC-16 in severe COPD compared to moderate ones (p<0.027). No statistically significant differences were found between CC-16 expression and sputum cellularity (except for macrophages), arterial blood gases, and spirometric parameters. Multiple linear regression analysis of CC-16 versus functional and cytological parameters showed no significance.


CONCLUSIONS
We found a significantly different expression of CC-16 in COPD patients, according to their stage of severity, as defined by the GOLD 2006 guidelines. Considering CC-16 properties in innate immunity, a possible link between protein expression, innate immune system, and COPD infectious exacerbations may be hypothesized but further investigation are needed.
Braido
Fulvio
F
Allergy and Respiratory Diseases, Department of Internal Medicine, University of Genoa, Pad. Maragliano, Largo R. Benzi, 10 16132 Genova, Italy. fulvio.braido@unige.it
Riccio
Anna M
AM
Guerra
Laura
L
Gamalero
Cinzia
C
Zolezzi
Alberto
A
Tarantini
Francesco
F
De Giovanni
Barbara
B
Folli
Chiara
C
Descalzi
Desideria
D
Canonica
Giorgio Walter
GW
D000368:Aged; D000369:Aged, 80 and over; D015415:Biomarkers / Q000378:metabolism; D005260:Female; D005541:Forced Expiratory Volume / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D029424:Pulmonary Disease, Chronic Obstructive / Q000175:diagnosis*; D012129:Respiratory Function Tests; D012141:Respiratory Tract Infections / Q000175:diagnosis*; D013183:Sputum / Q000737:chemistry* / Q000166:cytology; D014598:Uteroglobin / Q000378:metabolism*; D014797:Vital Capacity / Q000502:physiology
D015415:Biomarkers; C556389:SCGB1A1 protein, human; D014598:Uteroglobin