Serum Eosinophil Cationic Protein Levels in Patients with Allergic Diseases

Cha, Young Joo; Chae, Seok Lae; Chang, Eun Ah

Abstract

BACKGROUND
Eosinophil cationic protein (ECP), one of the eosinophil granule proteins released during allergic reactions, may play a major role in the allergic inflammatory process. The measurement of ECP in serum may be a useful indicator of eosinophil activity in ongoing inflammatory processes. We investigated the clinical utility of ECP measurement in serum in patients with bronchial asthma, allergic rhinitis and atopic dermatitis, after standardizing sample processing.
METHODS
We measured the serum ECP levels in patients with bronchial asthma (n=38), chronic obstructive pulmonary diseases (COPD) (n=13), respiratory symptoms (n=19), allergic rhinitis (n=26), non-allergic rhinitis (n=24), and atopic dermatitis (n=10) and in normal healthy controls (n=16) by the fluoroenzyme immunoassay using Pharmacia CAP System, and evaluated the correlation between ECP level and blood eosinophil number, or ECP and IgE levels. Blood eosinophil number was counted by the automated cell counter.
RESULTS
Serum ECP levels were significantly higher in patients with bronchial asthma (15.6+/- 12.6 g/L), COPD (13.3+/-7.2 g/L), allergic rhinitis (23.8+/-13.2 g/L), and atopic dermatitis (20.6+/- 18.4 g/L) than in normal controls (7.5+/-4.2 g/L) (P <0.05). ECP levels were also significantly higher in patients with bronchial asthma and COPD than in patients with simple respiratory symptoms (6.9+/-4.7 g/L), whose ECP levels did not statistically differ from those in normal controls. ECP levels were also significantly higher in patients with allergic rhinitis than in patients with non-allergic rhinitis (9.5+/-5.1 g/L), whose ECP levels did not statistically differ from those in normal controls. Serum ECP level and eosinophil number in peripheral blood were correlated only in patients with bronchial asthma (r=0.53, P <0.01) and no correlation between ECP and IgE levels was found in all of the patients.
CONCLUSIONS
ECP is the one of the secretory components released from the eosinophil granule and measurement of ECP in serum might be one of the noninvasive tool to assess the activity in relation to eosinophil involvement in various allergic diseases.