Role of serum eosinophil cationic protein as a biological marker to assess the severity of bronchial asthma

Objective: The study was carried out to evaluate the role of serum eosinophil cationic protein (ECP) as a biological marker for the diagnosis and to assess the severity of bronchial asthma. Methodology: This observational cross-sectional study was conducted among 70 bronchial asthma patients and 45 disease controls (tuberculosis-15, chronic obstructive pulmonary disease-15, interstitial lung disease-15) enrolled from patients attending the outpatient department of the National Institute of Disease of the Chest and Hospital (NIDCH), Dhaka, Bangladesh during July 2010 to June 2011. Global Initiative of Asthma Management and Prevention (GINA) criteria were followed for selection of both atopic and non-atopic patients with intermittent or persistent (mild, moderate Et severe) asthma. Serum level of eosinophil cationic protein (ECP), IgE, forced expiratory volume in 1 second (FEV1% predicted) and circulatory eosinophil (CE) count were estimated. Results: Mean serum ECP level (28.8 +/- 42.9 vs. 6.82 +/- 3.5 ng/mL; P<0.001), IgE level (383.59 +/- 225.3 vs. 135 +/- 131.8 IU/mL; P<0.001) and percent circulatory eosinophil count (9.95 +/- 3.7 vs. 5.95 +/- 1.4; P<0.024) were all found significantly raised among asthma patients than disease controls but %FEV1 was equivocal. All grades of persistent asthma patients had significantly (P<0.025 & P<0.002) higher mean ECP level than intermittent cases but serum IgE level and CE count did not differ significantly. FEV1% predicted correlated well among moderate and severe persistent asthma but was equivocal for intermittent and mild persistent cases. Conclusion: This study has reinforced that serum eosinophil cationic protein is a dependable biological marker with more discriminatory power over other indicators for bronchial asthma and to assess its severity.