TABLE 1.
Type 2 inflammation and phenotypic characteristics of asthma [3–5]
| Type 2-high asthma IL-4, IL-5, IL-13 | Type 2-low asthma |
| Blood eosinophilia (≥150 cells·µL−1 [6]) | Low blood eosinophil counts (<150 cells·µL−1) |
| Elevated tissue eosinophilia | Sputum neutrophilia (>40% of total cells [6–8]) |
| Elevated serum IgE (surpassing the normal range of 1.5–114 kU·L−1# [9, 10]) | Obesity associated |
| Elevated FeNO (>19.5 ppb [11]) | Poor response to corticosteroids |
| Upper airway comorbidities, including AR and CRSsNP/CRSwNP | |
| Other type 2 comorbidities, including EoE and AD | |
| Responsive to corticosteroids |
IL: interleukin; Ig: immunoglobulin; FeNO: fraction of exhaled nitric oxide; AR: allergic rhinitis; CRSsNP: chronic rhinosinusitis without nasal polyps; CRSwNP: chronic rhinosinusitis with nasal polyps; EoE: eosinophilic oesophagitis; AD: atopic dermatitis. #: value within the normal range does not exclude atopy [10].