[Cytokines and Proteases Involved in Pathogenesis of COPD]

COPD is characterized by persistence of chronic inflammation in small airways and alveoli. Macrophages, neutrophils, and a specialized subset of T lymphocytes orchestrate the mild inflammation. This article focuses on humoral factors such as cytokines and chemokines that recruit these inflammatory and immune cells to the lungs, and proteases/antiproteases that ultimately cause structural derangement in the terminal respiratory zones. In addition to the classical protease and antiprotease imbalance hypothesis, alveolar homeostasis abnormality that comes from imbalance of lung constitutional cell apoptosis and regeneration may play a role in emphysema development. Also, autoimmunity to elastin degradation products may take part in the disease.