Sverrild A, Andreasen AH, Westergaard CG, et al. - Researchers sought to determine if phenotypic characterization of patients with asthma can benefit from measuring airway hyperresponsiveness (AHR) to mannitol in addition to eosinophilic inflammation and symptoms. Study sample comprised 317 patients with asthma from six different cohorts. Experts discovered four clusters. Proportionate levels of AHR, eosinophilic inflammation and symptoms were detected in three of the clusters, but there were low levels of eosinophilic inflammation and a significant symptom burden in one cluster. Overall, a subgroup of asthma patients with symptomatic, non-eosinophilic disease was identified using information on AHR to mannitol in addition to blood eosinophils and symptoms. In a subgroup of patients suffering from non-eosinophilic asthma, AHR to mannitol may afford a treatable trait.