T helper 2 immune response (Th2 response)

The T helper 2 (Th2) immune response is a specialized arm of the adaptive immune system primarily responsible for defense against extracellular parasites, such as helminths, and the orchestration of humoral immunity (StatPearls, 2023). This pathway is characterized by the secretion of specific cytokines, most notably interleukin-4 (IL-4), IL-5, and IL-13, which promote B-cell class switching to IgE and the recruitment and activation of eosinophils and mast cells (Nature Reviews Immunology, 2018). While essential for host defense, an overactive or dysregulated Th2 response is the underlying driver of 'Type 2 inflammation,' which manifests as allergic diseases including asthma, atopic dermatitis, and allergic rhinitis (NEJM, 2019). In these conditions, environmental allergens trigger a Th2-mediated cascade leading to chronic airway or skin inflammation and tissue remodeling. Modern therapeutic strategies focus on biologics that selectively block key components of this pathway, such as monoclonal antibodies against IL-5 (e.g., mepolizumab) or the shared receptor for IL-4 and IL-13 (e.g., dupilumab). Consequently, modulating the Th2 response has become a cornerstone of personalized medicine in treating severe eosinophilic and atopic disorders (Journal of Allergy and Clinical Immunology, 2020).

Other names

Type 2 immunityTh2-mediated immunityType 2 inflammatory responseTh2 pathway

Drugs targeting this pathway typically inhibit specific type 2 cytokines (IL-4, IL-5, IL-13) or their corresponding receptors, or neutralize upstream alarmins like TSLP and IgE to suppress eosinophilic inflammation and allergic cascades.