IL17RB is a transmembrane cytokine receptor primarily functioning as a key responder to epithelial alarmins in type 2 inflammatory diseases. The receptor binds IL-17B and IL-17E cytokines 1 and serves as part of a receptor constellation on T helper 2A cells alongside IL1RL1 and CRLF2, enabling responses to IL-25, IL-33, and TSLP respectively 1. IL17RB expression characterizes memory-like group 2 innate lymphoid cells (ml-ILC2s) that reside in intestinal lamina propria and drive asthma relapse upon antigen re-exposure 2. In atopic dermatitis, IL17RB+ TH2A cells persist after clinical remission as disease-linked immune memory, facilitating rapid epidermal-dermal cross-talk and explaining disease recurrence following immunosuppressive treatment cessation 1. Beyond immune functions, IL17RB marks cancer stem cells in colorectal cancers, where it sustains tuft cell-like tumor stem cell expansion 3. Additionally, IL-17E signaling through IL17RB in cortical neurons modulates social behavior, revealing a neuroimmune function 4. IL17RB thus represents a multifunctional receptor controlling alarmin-driven type 2 inflammation, tissue-resident immune memory, cancer stem cell maintenance, and neuromodulation—making it a potential therapeutic target across allergic, autoimmune, oncologic, and neuropsychiatric conditions.