PERIVASCULAR T-CELLS EXPRESS THE PRO-INFLAMMATORY CHEMOKINE RANTES MESSENGER-RNA IN MULTIPLE-SCLEROSIS LESIONS

Multiple sclerosis (MS) is an inflammatory demyelinating disease of th e central nervous system (CNS), characterized by accumulation of monon uclear cells. The pathogenesis of MS is complex and probably involves soluble immune mediators, particularly cytokines, and activated memory T cells, that are thought to migrate into the CNS, During lesion form ation in MS, cytokines regulate cell functions, such as cell recruitme nt and migration. Because the chemokine RANTES play a role in both act ivating and recruiting leucocytes, particularly memory T cells into in flammatory sites, the authors have assessed RANTES mRNA levels at the site of lesions. Expression levels were analysed in brain samples and compared with neurological, infectious and other controls. RANTES was expressed by activated perivascular memory T cells, predominantly loca ted at the edge of active plaques. While RANTES mRNA was detected in a ll 17 MS brains analysed, it was only found in six of the 14 control p atients and generally at a lower expression level. In view of the regu latory and chemotactic properties of RANTES, these results imply that RANTES in MS lesions may play an important role in the activation and/ or selective accumulation of memory T cells and, thereby, in the patho genic events associated with MS.