A proinflammatory cytokine or more simply an inflammatory cytokine is a type of signaling molecule (a cytokine) that is excreted from immune cells like helper T cells (Th) and macrophages, and certain other cell types that promote inflammation. They include interleukin-1 (IL-1), IL-12, and IL-18, tumor necrosis factor (TNF), interferon gamma (IFN-gamma), and granulocyte-macrophage colony stimulating factor and play an important role in mediating the innate immune response. Inflammatory cytokines are predominately produced by and involved in the upregulation of inflammatory reactions