Eosinophilic cationic protein as a non-invasive marker of the nature of inflammatory response in patients with chronic obstructive pulmonary disease

Objective. To estimate the value of measuring plasma eosinophilic cationic protein (ECP) levels in patients with chronic obstructive pulmonary disease (COPD) as a potential biomarker for determining the activity of eosinophilic inflammation. To compare it to determining the number of blood eosinophils and predicting the severity of COPD by determining such clinical characteristics as respiratory function, exacerbation frequency and the BODE index.

Materials and methods. Based on the protocol, 161 patients with COPD participated in the study. They made 2 visits for the collection of anamnestic data and the performance of the main study procedures: respiratory function test, 6-minute step test, dyspnea assessment according to the Medical Research Council Scale questionnaire and sputum and blood analysis in order to determine the level of eosinophils and ECP. The second visit was conducted 12 months after the first to assess the dynamics of the disease. We paid particular attention to the presence of allergies in the case history, the frequency of exacerbations, the number of courses of treatment with antibacterial drugs and inhalants, and systemic glucocorticoids.

Results. The study has demonstrated that high plasma levels of ECP in patients with COPD are associated with a more severe course of disease and the development of more frequent infection-related exacerbations of the disease, which require the administration of inhaled glucocorticoids and antibiotics. We have demonstrated an inverse relationship between the ECP level and forced expiratory volume in 1 second (FEV1). This allows the use of this indicator as a predictor of the severity of COPD in patients.

Conclusion. According to the obtained data, measuring the ECP level of blood plasma can be recommended for use as a clinical marker in the prognosis of COPD and selection of personalized therapy. It is a noninvasive and a relatively easily accomplished research method.  

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