Associação entre a reversibilidade brônquica e a inflamação das vias aéreas em doentes com doença pulmonar obstrutiva crónica

Chronic Obstructive Pulmonary Disease (COPD) is a major cause of morbidity and mortality worldwide. It is characterized by airflow limitation and chronic inflammation of the lungs that varies significantly among patients. The aim of this study was to evaluate the pathophysiologic and inflammatory mechanisms in a group of patients with and without FEV₁, reversibility. We selected 24 moderate to severe, stable COPD patients, all ex-smokers, 12 with no reversibility and 12 with reversibility of airflow limitation to bronchodilator therapy. Lung function tests, exhaled nitric oxide (NO) concentrations, induced sputum and peripheral blood samples to determine cells and soluble mediators (interleukin-8, 5 and eosinophil cationic protein), were obtained from all subjects. This study confirmed the presence of chronic and persistent inflammation of the airways of COPD patients, with an increased number of neutrophils and IL-8 concentrations in sputum. Exhaled NO levels, sputum eosinophils and ECP were higher in COPD patients with bronchodilator reversibility, and this data could not explained by a production of IL-5 by a subpopulation of T cytotoxic cells. An inflammatory mechanism, different from asthma, seems to be responsible for the airflow reversibility. Exhaled NO and induced sputum are noninvasive methods that can identify COPD patients with eosinophilic airway inflammation. These methods can be useful in the early assessment of the disease and to predict and monitor the response to glucocorticosteroid treatment. Low body mass index was related to an increase in inflammatory mediators, namely IL-8, confirming the presence of systemic inflammation in COPD.