The role of macrophages in obstructive airways disease: Chronic obstructive pulmonary disease and asthma

•Macrophages play an important role in the regulation of inflammatory responses.•COPD and asthma both involve chronic inflammation of the respiratory tract.•The role of macrophages in asthma and COPD is beyond phagocytosis.•In COPD macrophages orchestrate inflammation by releasing chemokines and proteases.•In asthma macrophages are implicated in disease development and progression.

Macrophages are a major cellular component of the innate immune system, and play an important role in the recognition of microbes, particulates, and immunogens and to the regulation of inflammatory responses. In the lung, macrophages react with soluble proteins that bind microbial products in order to remove pathogens and particles and to maintain the sterility of the airway tract. Chronic obstructive pulmonary disease and asthma are both obstructive airway diseases that involve chronic inflammation of the respiratory tract which contributes to disease progression. In the case of COPD, there is increasing evidence that lung macrophages orchestrate inflammation through the release of chemokines that attract neutrophils, monocytes and T cells and the release of several proteases. On the other hand, in asthma, it seems that alveolar macrophages are inappropriately activated and are implicated in the development and progression of the disease. In this review we summarize the current basic and clinical research studies which highlight the role of macrophages in asthma and COPD.