Sputum and serum autoantibody profiles and their clinical correlation patterns in COPD patients with and without eosinophilic airway inflammation

Chronic obstructive pulmonary disease (COPD) is a major cause of morbidity and mortality worldwide, and is characterized by persistent respiratory symptoms and airflow limitation that is not fully reversible due to airway and/or alveolar lesions (1). Heterogenous and complex immunological responses and airway inflammation play critical roles in the pathogenesis and progression of COPD (2). There are various patterns of airway inflammation in COPD. Although it is generally accepted that neutrophilic inflammation is the major inflammation pattern in the airways during COPD, the concept of eosinophilic airway inflammation arose in the 1990s (3,4). Importantly, during stable COPD, sputum eosinophilia may predict the response to inhaled corticosteroids (ICS) used to prevent exacerbation of the disease (5-8)