Role of IL-5 in eosinophil-associated diseases and prospects for multi-target therapy

Eosinophil-associated diseases are a group of inflammatory disorders characterized by abnormal eosinophil infiltration, which significantly impacts patients' quality of life. Interleukin-5 (IL-5), a critical cytokine that regulates eosinophil development, activation, chemotaxis, and survival, plays a central role in the pathogenesis of these diseases. This review systematically examines the molecular structure and signaling pathways of IL-5, its mechanisms of action in asthma and chronic obstructive pulmonary disease (COPD), and the development and clinical applications of monoclonal antibodies (e.g., mepolizumab, benralizumab, reslizumab) and other biologics targeting IL-5. Although IL-5-targeted therapies have yielded significant results, single-target interventions still exhibit limitations, including insufficient responses in certain patients. To address this, we explore the strategy of multi-target combination therapies, such as the synergistic inhibition of IL-5 with the IL-4/IL-13 and IL-33/ST2 pathways. We also discuss the potential of novel therapeutic approaches, including bispecific antibodies and small-molecule inhibitors. Ultimately, multi-targeted precision therapies, tailored to individual inflammatory phenotypes, are anticipated to represent a new frontier in the management of eosinophil-associated diseases.