Eosinophils and T2 inflammation in severe asthma

Abstract

Asthma is a common chronic inflammatory disease of the airways that affects more than 330 million people globally. Severe asthma, despite being 5–10% of the total asthmatic population presents significant morbidity and high cost due to health care utilization. The management of severe asthma has dramatically changed with the use of biologics. However, biologics have been approved only for patients with severe asthma with type-2 mediated inflammation. Eosinophils are central in the T2 inflammatory process in asthma and this stands true for the severe form of the disease as well. In this review, we discuss basic insights into the pathogenesis of severe asthma related to eosinophilic inflammation and the pivotal role of T2 cytokines which have also become along with eosinophils the target of biologics. Novel biologics such as tezepelumab have demonstrated efficacy regardless of the blood eosinophil count and have shown promise for T2 low asthma, although to a lesser degree.