- Characteristics
- shown to exhibit plasticity and can change their phenotype depending on the local environment
Types
- M1 pro-inflammatory
- involved direct destruction of intracellular pathogens, and produce pro-inflammatory cytokines, as well as a T helper 1 (Th1)-cell environment
- M2 ant-inflammatory
- more heterogeneous group involved in
- down-regulating inflammation or pro-resolution and tissue repair, producing a Th2 environment.
- Further Subcategorization
- M2a (parasite destruction)
- M2b (immune regulation) and
- M2c (tissue remodelling and extracellular matrix (ECM) deposition).18
- more heterogeneous group involved in
- Resident alveolar macrophage (AMs)
- reside within the airway and alveoli
- maintain their population
- by proliferation in situ rather than having a reliance on the macrophage precursors in the blood.7 8
- Interstitial Macrophages
- located between alveolar epithelial cells
- Non resident Macrophages
- Evolve from monocytes .9
Many of the functions of the alveolar macrophage have been shown to be dysregulated following exposure to cigarette smoke.
Links and References
- Lugg, SL et al Cigarette smoke exposure and alveolar macrophages: mechanisms for lung disease BMJ Thorax