Cytokines in autoimmune disease.

Cytokines are peptide hormones that regulate a wide variety of immune and inflammatory processes. Individual cytokines are produced by many different cell types and exhibit pronounced pleiotropism. Cytokines such as tumor necrosis factor alpha interleukins -5, -10, and -12 play important roles in immunity. Interleukins -2 and -4, and transforming growth factor gamma mediate lymphocyte activation and differentiation.