Cytokines are peptide regulatory factors which are involved in initiating, amplifying, perpetuating and resolving the immune and inflammatory responses. Each may have several actions, but can be broadly categorized into pro- and anti-inflammatory cytokines. The cytokine profile depends on the nature of the antigen, how it is presented to the host, and which cell types are involved in the response. Elucidation of the cytokine cascade will improve understanding of the mechanisms of inflammation, and may allow the identification of therapeutic targets in chronic inflammatory diseases of unknown aetiology.