Anti-inflammatory cytokines and cytokine antagonists.

Cytokines are critical mediators of protective host responses, including defense against microbial invasion and tumorigenesis. However, the production of specific proinflammatory cytokines must be tightly regulated and compartmentalized to prevent the overzealous expression of these molecules that can culminate in unabated inflammation and tissue injury. Cytokine production and/or biologic effects can be inhibited by a variety of endogenous molecules, including anti-inflammatory cytokines, soluble cytokine receptors, and receptor antagonist proteins. Additionally, synthetic molecules have been constructed to selectively block the synthesis, post-translation processing, or receptor binding of proinflammatory cytokines. Relevant anti-inflammatory cytokines and cytokine inhibitors (both endogenous and synthetic) will be the subject of this review, with a particular emphasis on those anti-inflammatory cytokines and cytokine inhibitors that have been used experimentally or clinically in the treatment of diseases that are believed to be mediated by excessive proinflammatory cytokine responses.