The role of airway macrophages in apoptotic cell clearance following acute and chronic lung inflammation

Grabiec, Aleksander M.; Hussell, Tracy

In health, apoptotic cells are essentially undetectable in the lung tissue [69] , and immune cells infiltrating the airways which undergo apoptosis are rapidly cleared by airway macrophages in models of acute microbial infection-related lung inflammation [70] . Respiratory infections are therefore not associated with persistent accumulation of large quantities of apoptotic cells in the airspaces. However, increased numbers of dying cells are detected in the airspaces of patients with several aetiologically distinct chronic inflammatory lung diseases [71] . Although higher frequencies of apoptotic cells in these diseases might result either from elevated rates of apoptotic cell death or defects in apoptotic cell removal, experimental evidence suggests that reduced efficiency of efferocytosis, predominantly by airway macrophages, plays a key role in this pathological process [72, 73] .