EVIDENCE FOR EOSINOPHIL ACTIVATION IN BRONCHIECTASIS UNRELATED TO CYSTIC-FIBROSIS AND BRONCHOPULMONARY ASPERGILLOSIS - DISCREPANCY BETWEEN BLOOD EOSINOPHIL COUNTS AND SERUM EOSINOPHIL CATIONIC PROTEIN-LEVELS

Background-Increased serum levels of eosinophil cationic protein (ECP) have been detected in adolescent patients with cystic fibrosis. Howev er, ECP concentrations in adult patients with bronchiectasis unrelated to cystic fibrosis have not been studied. Methods-Eosinophil numbers and serum concentrations of ECP were determined in 14 patients with kn own or newly diagnosed bronchiectasis and compared with age and sex ma tched patients with allergic bronchial asthma, chronic obstructive pul monary disease (COPD), and controls in whom bronchiectasis or obstruct ive pulmonary disease could be excluded. Results-Serum ECP levels were significantly raised both in patients with bronchiectasis (median (ra nge) 22.5 mu g/l (7-85)) and allergic asthma (35.0 mu g/l (7-128)) com pared with the seu and age matched subjects suffering from COPD (6.7 m u g/l (1.5-28); p<0.006) and non-obstructive normal controls (7.5 mu g /l (3.5-19); p<0.003). In contrast, significantly increased peripheral eosinophil numbers were observed in patients with bronchial asthma (3 05 x 10(6)/l; p<0.01) but not in those with bronchiectasis (10(2) x 10 (6)/l), COPD (117 x 10(6)/l), and healthy controls (101x 10(6)/l). Con clusions-The discrepancy between eosinophil counts and eosinophil numb ers in patients with bronchiectasis suggests that serum ECP levels may be more relevant in assessing local eosinophil involvement than blood eosinophil numbers.