Eosinophils, white blood cells that are part of the immune system and are related to inflammatory processes, are key biomarkers for the treatment of Chronic Obstructive Pulmonary Disease (COPD). To identify its role in progression, a multi-centre study led by Dr Marc Miravitlles, a specialist in the Pneumology Department at Vall d’Hebron University Hospital and researcher of the Pneumology research group at Vall d’Hebron Research Institute (VHIR), concludes that high blood levels are associated with COPD. The study was carried out by several groups of the CIBER de Malalties Respiratòries (CIBERES) and has been published in Respiratory Research (Nature).

The study is based on EPISCAN II, a population-based epidemiology study promoted by the pharmaceutical company GSK, whose main objective is to investigate the prevalence and causes of COPD in Spain. The 12 participating hospital centres recruited 326 patients with COPD and 399 without the disease, with a mean age of 63.2 years, with 46.3% being men and 27.6% being active smokers.

As explained by Dr Miravitlles, “most of the clinical characteristics were significantly different between participants who had and did not have COPD. The former were older, more often male, smokers, with lower lung function parameters, lower exercise tolerance and higher scores on the COPD assessment test (CAT)”.

Blood eosinophil counts (BEC) were found to be higher in COPD patients, with 192 cells/μL compared to 160 cells/μL in those without the disease. The researchers therefore concluded that COPD patients have a higher presence of this type of white blood cell in their blood, and that male sex, active smoking and co-existing asthma were also associated with this.

In this respect, Borja G. Cossío, CIBERES researcher at the Son Espases-IdISBa University Hospital in Palma de Mallorca and the last signatory of the study, considers that “COPD is a heterogeneous disease with multiple phenotypes that may be associated with different prognoses and responses to treatment, such as that associated with increased eosinophilic inflammation. There is a broad consensus on the role of BEC as a biomarker for identifying patients who will have a better response to inhaled corticosteroids”.

To better understand the role of blood eosinophils as biomarkers of COPD, it is important to generate new data on the distribution of blood eosinophil values in healthy adult populations and different groups of patients with COPD according to phenotypes, severity and treatments, hence the aim of this work.

“The results of our population-based study provide an estimate of the distribution of eosinophils in the adult population in Spain and have shown that patients with COPD, even in mild stages, have a significantly higher BEC”, concluded Dr Marc Miravitlles.