They are important in health and disease, specifically in host responses to infection, immune responses, inflammation, trauma, sepsis, cancer, and reproduction.The word comes from Greek: cyto, from Greek "κύτος" kytos "cavity, cell" kines, from Greek "κίνησις" kinēsis "movement".Cytokines are produced by a broad range of cells, including immune cells like macrophages, B lymphocytes, T lymphocytes and mast cells, as well as endothelial cells, fibroblasts, and various stromal cells; a given cytokine may be produced by more than one type of cell.
Their definite distinction from hormones is still part of ongoing research.
Cytokines include chemokines, interferons, interleukins, lymphokines, and tumour necrosis factors but generally not hormones or growth factors (despite some overlap in the terminology).
For instance, to use hormone terminology, the action of cytokines may be autocrine or paracrine in chemotaxis or chemokinesis and endocrine as a pyrogen.
Further, as molecules, cytokines are not limited to their immunomodulatory role.
M) concentrations that can increase up to 1,000-fold during trauma or infection.