Making the case for causality: what role do lung microbiota play in idiopathic pulmonary fibrosis?

Though the notion of a “lung microbiome”, i.e. a complex community of microbes inhabiting and influencing the lower respiratory tract, is barely a decade old [1], there is nothing new about the idea that the lungs represent a crucial interface between us and the microbial universe we inhabit. Louis Pasteur demonstrated the presence of viable microbes in air [2], and one of his contemporaries calculated that healthy adults inhale between 1500 and 14 000 organisms each hour [3]. Yet more evidence that the lung microbiome plays a role in idiopathic pulmonary fibrosis. But how close are we to proving causality? An editorial from Dickson, Harari and Kolb in the ERJ. http://bit.ly/2Ps1ow4