Interleukin 10 is produced by regulatory T lymphocytes, B cells, and monocytes. It is a homodimer that functions through the IL-10R1 and IL-10R2 receptor complexes, activating such kinases as Janus kinase and tyrosine kinase 2. IL-10R2 receptor is presented in most cells, when IL-10R1 receptor is IL-10 is also an inhibitor of expressions of CD80 and CD86 by dendritic cells (DC) and antigen-presenting cells (APC), and of T cells, decreasing their cytokine production, therefore, controlling their activation. IL-10 plays a big role in regulating allergies by inhibiting cytokines responsible for allergic inflammation.