IL13RA1 (interleukin-13 receptor subunit alpha 1) is a cell surface cytokine receptor that binds interleukin-13 (IL-13) with low affinity 1 and forms a functional type II IL-4 receptor complex with IL-4Rα to mediate IL-13 signaling 2. The receptor activates JAK-STAT signaling through STAT6 and p38 MAPK pathways 3, driving multiple immune and metabolic responses. IL13RA1 is expressed on diverse cell types including fibroblasts, dendritic cells, epithelial cells, and preadipocytes, where it mediates type 2 inflammatory responses. In bullous pemphigoid, the IL-13-IL13RA1 axis orchestrates immune-stromal crosstalk between Th2 cells and fibroblasts/dendritic cells, amplifying pathogenic autoantibody responses 4. In eosinophilic esophagitis, epithelial IL13RA1 expression drives tissue remodeling and eosinophilia 2. IL13RA1 also regulates beige adipogenesis and metabolic homeostasis, with genetic variants associated with BMI and type 2 diabetes 3. Beyond immunity, IL-13 and IL13RA1 function as synaptic proteins in the brain, regulating neuronal plasticity and providing neuroprotection following traumatic brain injury 5. Alternative splicing generates a signaling-defective IL-13Rα1 isoform that fine-tunes type 2 cytokine responses 6.