Eosinophilic cationic protein (ECP) in the clinical work-up of chronic cough.

BACKGROUND: Chronic cough is a common symptom, addressed in the clinical setting by empirical treatment together with some laboratory investigations. The aim of the present study was to investigate the value of testing eosinophilic cationic protein (ECP) serum levels combined with other diagnostic procedures and empirical treatment in the diagnostic workup of chronic cough. METHODS: In this study, we evaluated 194 patients with chronic cough. No subject had received any anti-inflammatory treatment before clinical evaluation, and none was an active smoker. ECP was measured with a commercially available fluoroenzyme immunoassay and results were expressed as µg/L. RESULTS: The analysis of variance showed that mean ECP level differs among the various diagnosis categories (P<0.001). Mean ECP level was significantly higher in asthmatic patients, particularly in the active disease. CONCLUSIONS: Serum ECP concentration could represent a useful biomarker in the clinical work-up of chronic cough, managing to differentiate asthma from other chronic disorders.