[Cytokines. Transmittor substances of the immune system]

Cytokines are hormone-like proteins and peptides whose principal function is that of signalling substances within the immunoinflammatory and haematopoietic systems. Since the first cytokines were characterised 15 years ago, over 50 cytokines have been strictly defined and characterised. Cytokines are classified mainly on the basis of functional criteria into families--e.g, interleukins, interferons, colony stimulating factors, and chemokines. The article provides a broad review of cytokine physiology and pathophysiology with an emphasis on recent findings of their involvement in various diseases such as infections, autoimmune and haematological disorders, and cancer. Different treatment modalities that affect cytokine activity are discussed.