IL-33 has been associated with asthma susceptibility and can contribute to both T2 and non-T2 inflammation; it is therefore of interest that treatment of patients with severe asthma with astegolimab, a human IgG2 inhibitor the IL-33 receptor ST2, reduced annualised asthma exacerbation rates compared with placebo [129]. Here, IL33 is linked to asthma.