YKL-40, a chitinase-like protein at the intersection of inflammation and remodeling.

bacterial, may generate products that affect known or as yet unknown disease mechanisms. Chemical and molecular functions performed by certain organisms could modulate biologic markers of disease or even response to prescribed therapies (6). It is conceivable that the potential functional repertoire of the airway microbiome, like in the gut, encompasses a range of homeostatic, metabolic, and/or immunomodulatory functions. This may be on a different scale from the gut, where abundant functions have also been shown to not necessarily derive from the most common species in the community (16). Future clinical application of culture-independent microbial community analysis may better define states of infection and help prognosticate outcomes, particularly if coupled with measures of microbiome and host function. To achieve such goals, however, will require comprehensive and efficient platforms that provide timely information and facilitate insight into what influence genetics, environment, and/or therapeutics may have on the microbiome. Such knowledge could improve our delivery of more specific or appropriate therapies to improve clinical outcomes in airway disease.