Chemokines in vasculitis.

The systemic vasculitides are a group of diseases where the primary pathological process is inflammatory injury to blood vessel walls. Their clinical manifestations are highly variable and range from organ specific disease to a systemic illness that can lead, if untreated, to multi-organ failure and death. The kidneys are often involved in systemic vasculitis, particularly in small vessel vasculitis, where the glomerular capillary bed is a target for injury. This leads to a vasculitic glomerulonephritis, with focal segmental inflammation and perivascular leukocyte accumulation evolving to extracapillary accumulation of mononuclear cells (including crescents). The kinetics of leukocyte infiltration and involvement in this setting are in part dependent on the combinatorial expression of chemokines and their receptors. We discuss the evidence base for the role of the chemokine network in the renal disease of small vessel vasculitis and extend this to non-renal aspects of small vessel vasculitis other systemic vasculitides.