Alveolar and lung interstitial macrophages: Definitions, functions, and roles in lung fibrosis

M phi s are the main innate immune cells in the lung at homeostasis, with important roles in host defence and immune modulation. Alveolar M phi s (AMs) and interstitial M phi s (IMs) are the two lung M phi subsets, so called according to the sites they reside in. These subsets are also defined by their origins and immunological microenvironment, which endow these cells with distinct features and plasticity. This review summarizes the latest definitions and functions of lung M phi s during homeostasis and provides exemplar of their divergent roles in lung fibrosis.

Automated summary

Lung M phi s are the main innate immune cells in the lung, playing important roles in host defense and immune regulation during homeostasis. Alveolar M phi s (AMs) and interstitial M phi s (IMs) are two subsets of lung M phi s, distinguished by their locations and endowed with distinct features and plasticity based on their origins and immunological microenvironment. This review discusses the latest definitions and functions of lung M phi s at homeostasis and highlights their divergent roles in lung fibrosis.