(sīt'ŏ-kīn‵ )

Any of more than 100 small proteins produced and released by cells to affect the functioning of other cells. They provide signals to regulate immunological aspects of cell growth and function during both inflammation and specific immune response. Each cytokine is secreted by a specific cell in response to a specific stimulus. Cytokines produced by monocytes or macrophages and lymphocytes are called monokines and lymphokines, respectively. Cytokines include the interleukins, interferons, tumor necrosis factors, erythropoietin, and colony-stimulating factors. They act by changing the cells that produce them (autocrine effect) and altering other cells close to them (paracrine effect); a few affect cells systemically (endocrine effect).

SEE: granulocyte-macrophage colony-stimulating factor; immune response; inflammation; interferon; interleukin; macrophage; tumor necrosis factor.

proinflammatory c.Any of the circulating substances in the blood that deplete lean body mass in critical illness. They include several interleukins (IL-1, IL-6, and IL-8) and tumor necrosis factor.