The systemic face of airway diseases: the role of C-reactive protein

Airway diseases, predominantly asthma and chronic obstructive pulmonary disease (COPD), are highly prevalent diseases, constituting a major financial burden to society. Both asthma and COPD are identified by the presence of characteristic symptoms and functional abnormalities. Airflow limitation is the dominant physiological characteristic of both diseases. The airflow limitation in asthma must be reversible to establish a diagnosis, whereas in COPD the airflow limitation does not change markedly over periods of several months and the disease is characterised by a steady downhill course over time. Asthma usually commences in childhood, whereas COPD is generally diagnosed at an older age. Lung inflammation induced by different initiating factors is now recognised as an important characteristic in both diseases. The airway inflammation in asthma is characterised by an increase in eosinophils, lymphocytes (predominantly of the CD4+ type) and mast cells. In contrast, inflammation in COPD can be described by a predominance of lymphocytes, in particular CD8+ lymphocytes, and large numbers of neutrophils in the airway lumen. While achievement of asthma control and suppression of airway inflammation are considered as important management goals in asthma, particularly as a consequence of the effects of inhaled steroids in this disease process, the focus of research in COPD has moved from the typical pulmonary pathology of COPD to the role of numerous abnormalities outside the lung. At present, COPD is considered as a multicomponent disease, including skeletal muscle dysfunction and cachexia, as well as cardiovascular and osteoskeletal alterations. Particularly in order to explain the process of muscle wasting, the presence of a chronic low-grade systemic inflammatory response has been identified as one of the catabolic factors, although the precise role, as well as the intracellular pathways, remain to be defined 1. In this issue of the European Respiratory Journal (ERJ) , two clinical papers focus attention …