T2-“Low” Asthma: Overview and Management Strategies

Although the term "asthma" has been applied to all patients with airway lability and variable chest symptoms for centuries, phenotypes of asthma with distinct clinical and molecular features that may warrant different treatment approaches are well recognized. Patients with type 2 (T2)-"high" asthma are characterized by upregulation of T2 immune pathways (ie, IL-4 and IL-13 gene sets) and eosinophilic airway inflammation, whereas these features are absent in patients with T2-"low" asthma and may contribute to poor responsiveness to corticosteroid treatment. This review details definitions and clinical features of T2-"low" asthma, potential mechanisms and metabolic aspects, pediatric considerations, and potential treatment approaches. Priority research questions for T2-"low" asthma are also discussed. Although the term "asthma" has been applied to all patients with airway lability and variable chest symptoms for centuries, phenotypes of asthma with distinct clinical and molecular features that may warrant different treatment approaches are well recognized. Patients with type 2 (T2)-"high" asthma are characterized by upregulation of T2 immune pathways (ie, IL-4 and IL-13 gene sets) and eosinophilic airway inflammation, whereas these features are absent in patients with T2-"low" asthma and may contribute to poor responsiveness to corticosteroid treatment. This review details definitions and clinical features of T2-"low" asthma, potential mechanisms and metabolic aspects, pediatric considerations, and potential treatment approaches. Priority research questions for T2-"low" asthma are also discussed. Precision Medicine in Asthma—Using Phenotypes to Understand Endotypes That Lead Us to New Therapeutic OptionsThe Journal of Allergy and Clinical Immunology: In PracticeVol. 8Issue 2PreviewAs Fitzpatrick et al1 point out, "phenotypes" of asthma have been reported in the literature since the early 1940s. It is now well recognized that the term "asthma" identifies a group of disorders with distinct clinical features. This recognition, combined with an ability to analyze large multicenter datasets,2,3 has allowed identification of additional asthma clusters/phenotypes. Some of these phenotypes can be linked to an underlying biologic process (endotype) that can then drive a targeted treatment approach. Full-Text PDF CME Exam: T2-"Low" Asthma: Overview and Management StrategiesThe Journal of Allergy and Clinical Immunology: In PracticeVol. 8Issue 2Preview Full-Text PDF