Interleukin 10 (IL-10) is an anti-inflammatory cytokine and suppresses immune responses. IL-10 is secreted by macrophages, Th2 cells, and mast cells. Cytotoxic T cells also release IL-10 to inhibit viral infection stimulated natural killer cell activity. IL-10 inhibits the synthesis of a number of cytokines involved in the inflammatory process including IL-2, IL-3, granulocyte-macrophage colony-stimulating factor, tumor necrosis factor α (TNF-α), and interferon γ (IFN-γ) . It can promote the activity of mast cells, B cells, and certain T cells. The cytokine genes are polymorphic, which accounts for the different levels of cytokine production, and are related to regulation of the immune-mediated inflammatory process. Cytokine gene polymorphisms have recently attracted interest because distinct alleles of cytokine genes have been associated with various immunoinflammatory diseases (Audia et al., 2017).