Blood eosinophil count in patients with COPD on inhaled corticosteroids in comparison with healthy smoker and nonsmoker controls

Abstract

Background Chronic obstructive pulmonary disease (COPD) is associated with acute and chronic pulmonary inflammation in the lung and as a systemic inflammation. The blood eosinophil counts are now recommended by the Global Initiative for the Management of Obstructive Lung Disease as a guide of inhaled corticosteroid use in clinical practice, as it can predict its effect on the rate of COPD exacerbation. The increasing peripheral blood eosinophilic count in patients with COPD could explain the systemic eosinophilia in COPD, which causes increased lung eosinophil count in these patients, especially those on inhaled corticosteroids (ICS). Patients and methods The study included 56 patients with COPD who were active smokers with pack-years beyond 10 as cases. The control group includes 60 patients as healthy nonsmokers (HNS) and 66 patients as healthy current smokers (HS), with pack-year beyond 10. Prebronchodilator and postbronchodilator spirometry was done in the pulmonary function unit of the Chest Department, Ain Shams University Hospital, to confirm or to exclude the COPD diagnosis. The COPD cases were categorized as per the Global Initiative for the Management of Obstructive Lung Disease severity assessment guideline and were receiving budesonide 800 μg/day and formoterol 24 μg/day or salmeterol 100 μg and fluticasone propionate 500 μg twice daily. Skin prick test and complete blood count for its differential and eosinophil count were done for all cases. Results The study included 56 patients with COPD who were active smokers and received ICS. The control group included 60 patients as HNS along with 66 patients as healthy current smokers. The HNS group showed the least total leukocytic count of 5588.33±1081.13/µl and the least eosinophilic count of 99.47±91.51/µl, whereas the COPD group showed the highest total leukocytic count. A statistically significant relation was found also between COPD patients’ eosinophil count and the use of ICS, with P value 0.000. Conclusion The peripheral blood eosinophil counts collected from patients with COPD on ICS are significantly higher than the patients with COPD who are not using ICS and the healthy smoker and nonsmoker control group.

Keywords

• chronic obstructive pulmonary disease
• eosinophils
• inhaled corticosteroids