Serum Eosinophil Cationic Protein as a Biomarker of Asthma Severity and Disease Control: A GINA-Based Case–Control Study in Adults

Background: Eosinophil cationic protein (ECP) is a unique polypeptide containing 133 amino acids that possesses ribonuclease 3 activity. ECP is a critical marker in the pathophysiology of asthma and serves as a cytotoxic protein secreted by activated eosinophils; hence this biomarker also indicates eosinophilic airway inflammation. It harms the airway through bronchial hyperresponsiveness (BHR), raising mucus production, and killing epithelial cells. Objective: To determine serum Eosinophil cationic protein (ECP) levels in adults with asthma and to assess whether it can predict asthma severity (moderate vs severe), poor asthma control (controlled, partly controlled, uncontrolled), and its performance as a diagnostic marker. Methods: We studied 90 adults with asthma and 90 healthy adults. Patients were stratified by GINA severity (moderate n=56; severe n=34) and control (controlled n=31; partly controlled n=34; uncontrolled n=25). ELISA was used to measure Serum (ECP). Results: Serum Eosinophil cationic protein (ECP) concentrations were significantly higher in patients with asthma (Mean = 37.81 ± 12.77 ng/mL) than in control subjects (Mean = 13.80 ± 2.70 ng/mL; P < 0.001). ECP levels were elevated in severe asthma (Mean = 41.9 ng/mL) vs moderate disease (Mean = 35.3 ng/mL; p < 0.0049). The mean serum ECP levels were significantly higher in GINA Uncontrolled than Controlled subjects (p = 0.0130). Mean ± SD values for Controlled, Partially Controlled, and Uncontrolled groups were respectively 32.8 ± 10.6, 36.6 ± 9.9, and 41.9 ± 10.1 ng/mL. Conclusions: ECP levels are significantly higher in uncontrolled asthma. ECP is a dependable biomarker for detecting uncontrolled disease and evaluating asthma severity.