Fast Five Quiz: Type 2 Inflammation in Severe Asthma

Zab Mosenifar, MD


January 20, 2021

Type 2 inflammation in asthma is characterized by high antibody titers and eosinophilia or increased FeNO. It may also be accompanied by atopy. In comparison, non-type 2 inflammation is often characterized by increased neutrophils. About 50% of severe asthma cases are type 2.

Type 2 inflammation is often but not always driven by allergies. The phenotype is characterized by cytokines such as IL-4, IL-5 and IL-13, which are often produced by the adaptive immune system when spurred by allergens. Inflammation can also be triggered by viruses, bacteria, and irritants that stimulate the innate immune system.

In patients taking high-dose ICS or daily OCS, refractory type 2 inflammation should be considered if any of the following signs is observed:

  • Blood eosinophils ≥ 150/µL

  • FeNO ≥ 20 ppb

  • Sputum eosinophils ≥ 2%

  • Asthma is clinically allergy driven

Learn more about asthma phenotypes.


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