Inflammation in the central nervous system in multiple sclerosis: The role of chemokines and their receptors

Multiple sclerosis (MS) is characterised pathologically by inflammation and demyelination within the white matter of the central nervous system (CNS). The key effector cells in this process are T-lymphocytes and macrophages, which are recruited from the circulation across the blood brain barrier (BBB), and resident glial cells which also accumulate at the site of CNS inflammation. The directed movement of cells to sites of inflammation requires a series of soluble and cell-bound signals, the expression of complementary receptors by the target cell, adhesion molecule expression, rearrangement of the actin cytoskeleton, and degradation of the extracellular matrix (ECM). Chemokines are soluble chemoattractant proteins which bind to seven transmembrane domain, G-protein coupled receptors on their target cell. The following review discusses the role of chemokines in the activation and directional migration of specific cells in the pathogenesis of MS.