Correlation of eosinophil derived neurotoxin with airway resistance in asthmatics.

OBJECTIVE To determine the correlation of EDN with lung function tests (FVC, FEV1, FEV1/FVC and FEF25-75%) in asthmatics and to compare these with matched controls. METHODS This study was carried out at Army Medical College & Military Hospital, Rawalpindi, Pakistan. Forty four asthmatic patients and equal number of matching controls were selected. Lung function tests were done by using compact spirometer. Severity of asthma was graded according to the American Thoracic Society (ATS) "Asthma severity code and classification chart." Venous blood was used for estimation of eosinophil count while serum was used for estimation of EDN by ELISA. Correlation between EDN and various lung functions were calculated. RESULTS The asthmatic patients had significantly more eosinophil count (p<0.001) and Serum EDN levels (p<0.001) than the controls. A significant correlation (r = 0.934, p<0.001) was found between eosinophil count and EDN. A significant correlation between absolute eosinophil count and some of the lung functions [% predicted FEV1 (r = -0.908, p<0.001) and FEV1/FVC (r = -0.830, P<0.001)] was found. A similar significant correlation was found between EDN and some of the lung functions [% predicted FEV1 (r = -0.855, p<0.001) and FEV1/FVC (r = -0.814, P<0.001)]. Absolute eosinophil count and EDN increased significantly (p<0.001) with increasing severity of asthma. CONCLUSION Serum EDN has significant correlation with changes in lung functions and severity of asthma.