Cytokines play a major role in orchestrating the response of the immune system to invasion by pathogenic organisms. In the late 1980s several cytokines were described that not only modulated the activity of immune cells but also elicited their migratory responses. These newly described cytokines, of which interleukin 8 (IL-8) was a prototypic member, delineated a new branch of cytokines called chemokines (chemo-tactic cytokines). Chemokines are small mainly basic proteins that have been classified into four distinct families, CXC, CC, C, and CX3C, based on the position of their con-served cysteine residues. The two major branches are the CXC and CC chemokines. CXC chemokines include IL-8 and melanoma growth stimulatory activity (MGSA) and are mainly involved in acute inflammation, inducing the migration of neutrophils. The CC chemokines include RANTES, MCP-1 and MIP-1α and are primarily involved in chronic inflammation chemoattracting monocytes and T cells.