Immunosuppressant ingredients are chemical and medicinal agents used for the suppression and regulation of immune responses. Pharmacologically speaking, these agents have varied mechanisms of action, such as regulation of inflammatory gene expression, suppression of lymphocyte signal transduction, neutralization of cytokine activity, and inhibition lymphocyte proliferation by agent-induced cytotoxicity. Common agents include glucocorticoids, alkylating agents, metabolic antagonists, calcineurin inhibitors, T-cell suppressive agents, and cytokine inhibitors.