The lung is more than an organ of gas exchange: immunocompetency, platelets and implications for drug discovery

The lungs have for a long time been recognised as having pharmacological significance as a specific organ to modulate the pharmacokinetics of endogenous substances needed to maintain homeostasis. The lungs are therefore the site of action of certain drugs that act on these homeostatic processes, resulting in systemic effects on the cardiovascular system and blood. We now understand that the lungs are also a specialised site for haematopoiesis, with integration into the body's immune system. This may have significance given the exposure of the lungs to the environment and their resident microbiota. Within this new understanding, the lungs have also been reported as a significant site of thrombopoiesis, with a reservoir of megakaryocytic precursors that give rise to a megakaryocyte and platelet population with a distinct immunophenotype compared to circulating and bone marrow-derived cells. This article reflects on the potential importance of these discoveries and pharmacological opportunities that may result to control immune/inflammatory responses via selective control of platelet activation in the context of inflammation compared to haemostasis.