IL13

Interleukin-13 (IL-13) is a cytokine in the interleukin-4 family that shapes type 2 immune responses. It is produced mainly by TH2 cells, but also by group 2 innate lymphoid cells (ILC2), mast cells, and basophils. The IL13 gene is located in the cytokine gene cluster on chromosome 5q31.

IL-13 signals through a receptor complex consisting of IL-13Rα1 and IL-4Rα, forming the type II IL-4 receptor. IL-13Rα2 acts as a high-affinity decoy receptor in some tissues. Signaling activates JAK kinases and the transcription factor STAT6, with contributions from MAPK and PI3K pathways in certain cell types. This drives changes in gene expression that affect epithelial cells, macrophages, and fibroblasts.

Biological effects include induction of mucus production and goblet cell hyperplasia in the airways, airway remodeling, and regulation of IgE responses; it also promotes alternative macrophage activation and tissue repair. IL-13 collaborates with IL-4 to promote IgE class switching in B cells and can suppress Th1 responses. While important for defense against helminths, IL-13 is a key driver of allergic inflammation.

Clinically, IL-13 is implicated in asthma and atopic dermatitis, where its levels correlate with disease activity. Therapeutic approaches include monoclonal antibodies targeting IL-13, such as tralokinumab and lebrikizumab, and strategies that block IL-4Rα, such as dupilumab, which inhibits signaling of both IL-4 and IL-13. Efficacy varies by disease and patient endotype, and ongoing research seeks to refine these therapies.