Eosinophils and eosinophilic cationic protein in induced sputum and blood: effects of budesonide and terbutaline treatment.
BACKGROUND
There is a need for easily measurable markers of airway inflammation to guide the use of anti-inflammatory treatment in asthma. Eosinophilic cationic protein (ECP) levels in sputum and blood correlate with clinical severity, and serial measurements of ECP have been proposed as a suitable candidate.


OBJECTIVE
Our aim was to confirm that sputum and serum ECP measurements would provide a more sensitive indicator of responses to asthma treatment than eosinophil counts per se, in a randomized, placebo-controlled, crossover study of terbutaline, budesonide, and their combination in patients with chronic persistent asthma. We compared the changes in eosinophil counts and ECP in induced sputum and blood during each treatment period.


RESULTS
Budesonide and combined treatment caused a significant reduction in sputum eosinophils (-2.7% and -2.3%, respectively, P < 0.05). Sputum eosinophils increased with terbutaline (+3.9%, P = 0.049). In contrast, the changes for sputum ECP were not significant. There was a similar treatment effect on blood eosinophils, but not for serum ECP. Correlations between sputum and blood eosinophils were significant with and without budesonide, but were nonsignificant between sputum and blood ECP during the active treatments. Correlations between sputum eosinophils and ECP, and between blood eosinophils and serum ECP were greatest during treatment with placebo or terbutaline alone: budesonide weakened or abolished these relationships.


CONCLUSIONS
Compared with eosinophil counts, ECP measurements in either induced sputum or serum failed to reflect treatment-related changes in chronic asthma. We conclude that ECP is not a sensitive or reliable means of evaluating airway inflammation, and can not be recommended for assessing responses to anti-inflammatory therapy.
Aldridge
Ruth E
RE
Canterbury Respiratory Research Unit, Christchurch School of Medicine, University of Otago, Christchurch Hospital, Christchurch, New Zealand.
Hancox
Robert J
RJ
Cowant
Jan O
JO
Frampton
Chris M
CM
Town
G Ian
GI
Taylor
D Robin
DR
D000287:Administration, Topical; D000328:Adult; D000893:Anti-Inflammatory Agents / Q000494:pharmacology* / Q000627:therapeutic use; D001249:Asthma / Q000097:blood / Q000188:drug therapy / Q000378:metabolism*; D001798:Blood Proteins / Q000187:drug effects / Q000378:metabolism*; D001993:Bronchodilator Agents / Q000494:pharmacology; D019819:Budesonide / Q000494:pharmacology* / Q000627:therapeutic use; D047091:Eosinophil Granule Proteins; D004804:Eosinophils / Q000187:drug effects* / Q000378:metabolism; D005260:Female; D005938:Glucocorticoids; D006801:Humans; D018836:Inflammation Mediators / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D012260:Ribonucleases; D013183:Sputum / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D013726:Terbutaline / Q000494:pharmacology* / Q000627:therapeutic use; D016896:Treatment Outcome
D000893:Anti-Inflammatory Agents; D001798:Blood Proteins; D001993:Bronchodilator Agents; D047091:Eosinophil Granule Proteins; D005938:Glucocorticoids; D018836:Inflammation Mediators; D019819:Budesonide; D012260:Ribonucleases; D013726:Terbutaline