Interleukin-6 as a biomarker for asthma: hype or is there something else?

Much of precision medicine research today seeks to find a biomarker, or like King Richard, our kingdom might be lost. The hope is that if one is successful in identifying such a biomarker [1], all will be resolved: diagnosis, prognosis and the best treatment regime identified from the morass of treatment options available. In this context, the research for a single, do-all biomarker is a truly dramatic irony because it may not exist, consider the rise and fall of C-reactive protein (CRP) or exhaled nitric oxide fraction (FeNO). Yet such a biomarker could be quite useful in asthma, a syndrome that so often defies definition. With this mythical biomarker, one could clearly decide whether the patient has asthma, assess how severe the disease is, and even guide selection of which of the many available treatment regimens should be employed.