title: Asthma phenotypes and endotypes.
abstract: OBJECTIVE
  It is increasingly clear that asthma is not a single disease, but a disorder with vast heterogeneity in pathogenesis, severity, and treatment response. In this review, we discuss the present understanding of different asthma phenotypes and endotypes, and the prospects of personalized medicine for asthma.
  
  
  RESULTS
  The recognition of diverse biological backgrounds in which asthma, and particularly severe asthma, can manifest has prompted the search for refined phenotypes and endotypes in asthma. Such appreciation of the heterogeneity in asthma is also prompting clinical trials to focus on specific subgroups of asthma, as demonstrated by the clinical trial of lebrikizumab.
  
  
  CONCLUSIONS
  Patients with severe asthma have asthma symptoms that are difficult to control, require high dosages of medication, and continue to experience persistent symptoms, asthma exacerbations or airflow obstruction even with aggressive therapy. Although asthma is traditionally viewed as an eosinophilic inflammatory disorder associated with a T-helper cell type 2 (Th2) immune response, recent studies have identified involvement of other effector cells, nonclassical Th2 cytokines and non-Th2 cytokines in severe asthma pathogenesis. Results of several clinical trials of anticytokine antibodies demonstrated the effectiveness of tailoring asthma treatment on the basis of an individual's biology.
authors.affiliation: Meakins-Christie Laboratories, McGill University, Montreal, Quebec, Canada.
authors.forename: Ting-Yu
authors.initials: TY
authors.lastname: Lin
authors.forename: Audrey H
authors.initials: AH
authors.lastname: Poon
authors.forename: Qutayba
authors.initials: Q
authors.lastname: Hamid
mesh_terms: D018927:Anti-Asthmatic Agents / Q000627:therapeutic use; D000911:Antibodies, Monoclonal / Q000627:therapeutic use; D001249:Asthma / Q000145:classification* / Q000188:drug therapy* / Q000209:etiology; D019468:Disease Management; D006801:Humans; D010641:Phenotype; D057285:Precision Medicine; D016896:Treatment Outcome
chemical_list: D018927:Anti-Asthmatic Agents; D000911:Antibodies, Monoclonal; C561806:lebrikizumab