IL-13 is an immune regulatory cytokine produced primarily by activated Tʜ2 cells as well as mast cells and NK cells. Signaling through the IL-13 receptor activates the JAK/STAT and IRS-1/IRS-2 pathways. IL-13 has anti-inflammatory effects on monocytes and macrophages and it inhibits the expression of inflammatory cytokines such as IL-1β, TNF-α, IL-6, and IL-8. IL-13 has also been shown to enhance B cell proliferation and to induce isotype switching, resulting in increased production of IgE. Although IL-13 is involved in the pathogenesis of airway diseases such as asthma, it also plays a protective role for the mucosa, via induction of matrix metalloproteinases (MMPs) and other anti-inflammatory effects. In addition, IL-13 plays an important role in the expulsion of gastrointestinal parasites.
