Cytokines represent a unique family of endogenous polypeptide mediators of intercellular interaction. From an immunopharmacological point of view cytokines can be marked out as a new, separate immunoregulatory molecule system and have some common biochemical properties and pleiotropic type of biological activity. In the cytokine regulatory system both reduction and elevation of cytokine levels can cause pathology. Several endogenous systems exist to control cytokine elevation and prevent tissue pathology. When synthesized simultaneously, cytokines form a cytokine chain. Deletion of any unit of this chain leads to the break in the formation of immunopathology. Cytokines as therapeutic preparations have evident advantages but also some limita...