Chemokines in inflammatory bowel disease

Chemokines (chemotactic cytokines) are small (7–10 kDa) heparin binding proteins that govern the migration of circulating leucocytes to the sites of inflammation.¹ Chemokines, currently numbering more than 50, are classified into four supergene families based on cysteine residues: CXC, CC, C, and CX3C chemokines (table 1).² Chemokines are distinguished from other cytokines by acting on the G protein coupled serpentine receptors.²

Chemokines are classified into constitutively secreted and inducible.³ Those that are constitutively secreted are homeostatic chemokines directing basal leucocyte trafficking and the organisation of the lymphoid tissue. Inducible chemokines are inflammatory molecules responsible for mediating the recruitment of leucocyte effector populations to the sites of immune reaction and tissue injury.³

“Aberrant leucocyte chemoattraction occurs in chronic inflammatory diseases and is characterised by an excessive recruitment of inflammatory cells into the injured tissue”

The biological effects of chemokines are achieved by their interaction with specific receptors on the surface of the target cells. There are a few receptors that bind a single ligand, whereas several chemokines can bind to more than one receptor (table 1).

Aberrant leucocyte chemoattraction occurs in chronic inflammatory diseases and is characterised by an excessive recruitment of inflammatory cells into the injured tissue. In such processes, chemokines tightly control the multistep paradigm of leucocyte adhesion to and migration across the endothelium (fig 1).⁴ Ligation of chemokines to their receptors increases the …