title: Severe asthma: definition and mechanisms.
authors.affiliation: National Heart Lung Institute, Imperial College, London, UK.
authors.forename: R G
authors.initials: RG
authors.lastname: Stirling
authors.forename: K F
authors.initials: KF
authors.lastname: Chung
mesh_terms: D001249:Asthma / Q000175:diagnosis* / Q000453:epidemiology / Q000503:physiopathology / Q000628:therapy*; D003937:Diagnosis, Differential; D006801:Humans; D015995:Prevalence; D012307:Risk Factors; D012720:Severity of Illness Index