The Central Role of Th2 Immune Response in Inflammatory Dermatoses: From Pathogenesis to Targeted Therapies
Valentina Pala, François Rosset, Luca Mastorino, Nadia Sciamarrelli, Sara Boskovic, Silvia Borriello, Eleonora Bongiovanni, Orsola Crespi, Simone Ribero, Pietro Quaglino
Abstract
Th2 cells that produce interleukin (IL)-4, IL-5, IL-13, and IL-31, promoting immunoglobulin E (IgE) class switching, eosinophil recruitment, mast cell degranulation, and pruritus. We aimed to place these conditions in context and clarify how Th2 biology informs diagnosis and therapy. We conducted a narrative synthesis of mechanistic, translational, and clinical evidence on Th2 pathways in atopic dermatitis (AD), prurigo nodularis, bullous pemphigoid, chronic spontaneous urticaria, and selected type I/IVb hypersensitivity reactions, with focused appraisal of trials targeting IL-4Rα, IL-13, and IL-31R. Persistent Th2 activation is associated with epidermal barrier dysfunction, immune dysregulation, and pruritogenic neural signaling; AD is the archetype, showing prominent lesional IL-4/IL-13 activity correlated with severity and itch. Across disorders, pathway-directed biologics against IL-4Rα, IL-13, and IL-31R consistently reduce disease activity and pruritus in AD and prurigo nodularis, with emerging signals of benefit in bullous pemphigoid and chronic spontaneous urticaria. The Th2 axis provides a unifying pathogenic framework and actionable therapeutic target across multiple dermatoses. Integrating cytokine profiling with clinical phenotypes may refine patient stratification and optimize the deployment of existing and next-generation Th2-targeting therapies.