Thymic Stromal Lymphopoietin and Tezepelumab in Airway Diseases: From Physiological Role to Target Therapy

Thymic stromal lymphopoietin (TSLP), is a protein belonging to a class of epithelial cytokines commonly called alarmins, which also includes IL-25 and IL-33. Functionally, TSLP is a key player in the immune response to environmental insults, initiating a number of downstream inflammatory pathways. TSLP performs its role by binding to a high-affinity heteromeric complex composed of the thymic stromal lymphopoietin receptor (TSLPR) chain and IL-7Rα. In recent years, the important role of proinflammatory cytokines in the etiopathogenesis of various chronic diseases such as asthma, chronic rhinosinusitis with nasal polyposis (CRSwNP), chronic obstructive pulmonary diseases (COPDs), and chronic spontaneous urticaria has been studied. Although alarmins have been found to be mainly implicated in the mechanisms of type 2 inflammation, studies on monoclonal antibodies against TSLP demonstrate partial efficacy even in patients whose inflammation is not definable as T2 and the so-called low T2. Tezepelumab is a human anti-TSLP antibody that prevents TSLP-TSLPR interactions. Several clinical trials are evaluating the safety and efficacy of Tezepelumab in various inflammatory disorders. In this review, we will highlight major recent advances in understanding the functional role of TSLP, its involvement in Th2-related diseases, and its suitability as a target for biological therapies.