Eosinophil soluble protein levels, eosinophil peroxidase and eosinophil cationic protein in asthmatic patients

Eosinophil granular proteins are useful eosinophil activation markers in asthmatic patients. In this study, eosinophil peroxidase (EPO) and eosinophil cationic protein (ECP) levels were assessed in different stages of bronchial asthma in 123 patients suffering from intrinsic (n = 42) and extrinsic (n = 81) asthma, with the aim of evaluating the difference in the protein levels between both types of asthma and their importance as a severity marker of the disease.

The geometric mean serum level of EPO was 12.3 +/- 2.17 ng/ml (mean +/- SD) in controls, and 38.6 +/- 3.4 ng/ml in the asthmatic patients. Mean ECP levels were 13.22 +/- 1.11 ng/ml in controls and 30.5 +/- 2.38 ng/ml in patients. Depending on the asthma severity, the EPO levels were 30.4 +/- 4.35, 38.7 +/- 5.29, and 54.46 +/- 9.46 ng/ml in mild, moderate and severe asthmatics, respectively, with the differences being significant between the groups of patients with mild and severe asthma (p < 0.001). ECP levels were 24.23 +/- 3.37 in mild, 31.69 +/- 4.21 in moderate, and 37.61 +/- 4.52 ng/ml in severe asthma. There were significant differences in ECP levels between mild and moderate asthma (p < 0.001) and between mild and severe asthma (p < 0.001).

Peripheral eosinophil count was 157 +/- 20 eosinophils/mm3 in controls, 334 +/- 35 eosinophils/mm3 in mild asthmatics, 510 +/- 87 eosinophils/mm3 in moderate asthmatics and 658 +/- 72 eosinophil/mm3 in severe asthmatics, with significant differences between all groups (p < 0.05-p < 0.001). Serum EPO and ECP levels and peripheral eosinophil count were significantly greater in patients with active asthma than in patients with silent asthma (p < 0.001). Significant negative correlations (p < 0.001) were found between serum EPO levels and FEV1 (rs = -0.30), MEF25-75 (rs = -0.33), MEF50 (rs = -0.34). There was also a significant (p < 0.001) and negative correlation between ECP levels and FEV1 (rs = -0.31), MEF25-75 (rs = -0.31), MEF50 (rs = -0.32).

A good positive correlation was found between peripheral eosinophil count and EPO levels (rs = 0.80, p < 0.001), and ECP levels (rs = 0.67, p < 0.001). We also found a significant positive correlation between clinical score and peripheral eosinophil count (rs = 0.54, p < 0.001), EPO levels (rs = 0.46, p < 0.001) and ECP levels (rs = 0.52, p < 0.001).

CITATION J Investig Allergol Clin Immunol. 1999 Jan-Feb;9(1):27-34