Journal of the Neurological Sciences, 1985,69:269-283 269 Elsevier Inflammatory Vasculitis in Multiple Sclerosis C. W. M. Adams, R.N. Poston, S.J. Buk, Y. S. Sidhu and H. Vipond Department of Pathology, Guy's Campus, UnitedMedical and Dental Schools of Guy's and St Thomas's Hospitals, St Thomas's Street, London SE1 9RT (U.K.) (Received30 October, 1984) (Revised,received 13 March, 1985) (Accepted 13 March, 1985) SUMMARY Fifty-two plaque or lesion areas were examined from 25 cases of multiple sclerosis. Twenty-four of these showed acute features, whereas the rest were more chronic in nature. The acute lesions showed lymphocytic inftltration (79~0), fibrinous exudation (63 ~), lymphocytic meningitis (50~o) and venulitis (58~). Of the chronic lesions, there were only 21 ~o with lymphocytic infiltration, 11 ~o with fibrinous exudates, none with meningitis, 29~o with organising endovenulitis, 36~ with fibrosed vein walls. The finding of a fibrinous inflammatory exudate in the acute lesion is a new observation in multiple sclerosis. Likewise, the observation of an inflammatory int'fltrate confined to the vein wall (and often present at a distance from the plaque) has not been previously recorded in the disease. The chronic lesion, by contrast, showed relatively little fibrin, but there was considerable reparative thickening of the walls of the involved veins. The evidence provides new humoral and cellular evidence of an inflammatory process in multiple sclerosis which precedes or is not directly associated with the demyelinating process. Key words: Exudate- Fibrin- Inflammation- Lymphocyte- Macrophage- Meningitis - Multiple sclerosis - Thrombosis - Vasculitis - Venulitis INTRODUCTION The involvement of venules in multiple sclerosis, particularly in the form of a periphlebitis or inflammatory infiltration around venules, has been intermittently The workwas supportedby two grants fromthe MedicalResearchCouncil. 0022-510X/85/$03.30 © 1985 ElsevierSciencePublishers B.V.(BiomedicalDivision)