Cytokines are low molecular weight extracellular signalling proteins secreted by specific cells. Their effect is generally paracrine: altering the behaviour of cells in their close proximity. However, they may also act in an endocrine or autocrine manner.
They are secreted by a vast range of cells; those secreted by lymphocytes are termed lymphokines; cytokines secreted by monocytes are termed monokines.
Cytokines have an ever-increasing array of functions: most are centred around immune and inflammatory responses. Their is frequent overlap and interaction of effects.
Therapeutic use of cytokines is becoming more common; examples include:
Last reviewed 01/2018