Sputum eosinophilia can predict responsiveness to inhaled corticosteroid treatment in patients with overlap syndrome of COPD and asthma

Abstract

BackgroundChronic obstructive pulmonary disease (COPD) and asthma may overlap and converge in older people (overlap syndrome). It was hypothesized that patients with overlap syndrome may have different clinical characteristics such as sputum eosinophilia, and better responsiveness to treatment with inhaled corticosteroid (ICS).MethodsSixty-three patients with stable COPD (forced expiratory volume in 1 second [FEV1] ≤80%) underwent pulmonary function tests, including reversibility of airflow limitation, arterial blood gas analysis, analysis of inflammatory cells in induced sputum, and chest high-resolution computed tomography. The inclusion criteria for COPD patients with asthmatic symptoms included having asthmatic symptoms such as episodic breathlessness, wheezing, cough, and chest tightness worsening at night or in the early morning (COPD with asthma group). The clinical features of COPD patients with asthmatic symptoms were compared with those of COPD patients without asthmatic symptoms (COPD without asthma group).ResultsThe increases in FEV1 in response to treatment with ICS were significantly higher in the COPD with asthma group. The peripheral eosinophil counts and sputum eosinophil counts were significantly higher. The prevalence of patients with bronchial wall thickening on chest high-resolution computed tomography was significantly higher. A significant correlation was observed between the increases in FEV1 in response to treatment with ICS and sputum eosinophil counts, and between the increases in FEV1 in response to treatment with ICS and the grade of bronchial wall thickening. Receiver operating characteristic curve analysis revealed 82.4% sensitivity and 84.8% specificity of sputum eosinophil count for detecting COPD with asthma, using 2.5% as the cutoff value.ConclusionCOPD patients with asthmatic symptoms had some clinical features. ICS should be considered earlier as a potential treatment in such patients. High sputum eosinophil counts and bronchial wall thickening on chest high-resolution computed tomography might therefore be a good predictor of response to ICS.

The role of airway epithelial cells and innate immune cells in chronic respiratory disease

“…Peripheral blood and sputum eosinophilia is often used as a biomarker of a type 2 immune response, as well as responsiveness to glucocorticoids or type 2 cytokine-blocking treatments in patients with asthma 144–146 . Similar utility is found in tracking airway eosinophilia in patients with COPD, which probably reflects the overlap between asthma and COPD 147,148 . Recent studies suggest that eosinophils are activated in response to IL-33 in a manner that depends, at least in part, on a nuclear factor-κB (NF-κB)-dependent mechanism 149 , but as yet there is no experimental or clinical evidence of a functional role for eosinophils in post-viral airway disease.…”

Ashtma-Chronic obstructive pulmonary disease overlap syndrome (ACOS): current evidence and future research directions

“…Thus individualized management is probably the best option at present. Among the predictors for ICS response may be high sputum eosinophil counts and bronchial wall thickening on chest highresolution computed tomography [78].…”

LAMA/LABA vs ICS/LABA in the treatment of COPD in Japan based on the disease phenotypes

“…Exacerbations in individuals with COPD but no history of asthma can also present along with airway eosinophilia 52. These patients have good short- and long-term responses to glucocorticoids, and a raised blood eosinophil count has been shown to be a good biomarker of this pattern of airway inflammation 53–55. Titration of ICS treatment to reduce the concentration of airway eosinophils attenuates the frequency of severe acute exacerbations of COPD 51.…”

“…In patients with asthma, blood eosinophils had the highest accuracy in predicting eosinophilic airway inflammation 61. Therefore, the use of blood eosinophils can facilitate individualized treatment and management of COPD patients by identifying the eosinophilic nature of the airway inflammation 51,54,55…”

“…The benefit associated with ICS/LABA use was greatest among patients with a prior diagnosis of asthma, suggesting that ACOS is a common clinical problem among older COPD patients and merits treatment with an ICS/LABA combination for this subphenotype. The presence of blood eosinophilia in COPD patients without asthma can also identify those more responsive to corticosteroids 51,55. In addition, one study demonstrated that the presence of an allergic phenotype is associated with increased risk of lower respiratory symptoms and respiratory exacerbations among individuals with COPD,75 suggesting that the presence of allergic sensitization is another good indicator for ICS/LABA treatment because allergic sensitization, assessed by allergen-specific IgE or skin-prick testing, is a known risk factor for asthma and its severe symptoms.…”