Patients with cystic fibrosis (CF) and elevated blood eosinophil counts had significantly increased respiratory symptoms compared to those with lower eosinophil counts, based on data from 109 individuals.
Elevated blood eosinophil counts have been associated with worse outcomes in conditions including asthma and COPD, but their impact in patients with CF has not been well studied, write Si Cong Yi, MD, of the University of British Columbia, Vancouver, Canada, and colleagues.
"Circulating eosinophil count is an attractive biomarker in CF lung disease as it is readily available, extensively studied in other airway diseases, correlates well with airway eosinophilia in other airway conditions, and there is a plausible biological role for eosinophils in CF lung injury," they say.
For the retrospective study, published in the Journal of Cystic Fibrosisresearchers reviewed data from 109 adults with CF aged 19 years and older who were enrolled in a prospective cohort study of blood biomarkers between 2012 and 2018. Patients were grouped according to blood eosinophil counts defined as high (≥ 300 cells/μL) or low (< 300 cells/μL) at a stable clinic visit. The primary outcome was rate of pulmonary exacerbations (PEx) that required intravenous antibiotics, lung function decline, and level of respiratory symptoms using Cystic Fibrosis Respiratory Symptom Diary-Chronic Respiratory Infection Symptom Scores (CFRSD-CRISS) over a 1-year follow-up period.
