The present report describes immunopathological, radiological and serological characteristics of antibody-mediated demyelination in a multiple sclerosis (MS) case with the main findings: (I) immunoglobulin and complement deposits in areas of active demyelination accompanied by massive macrophage activation; (2) ring-enhancing lesions in TI-weighted MRI after gadolinium application; (3) high titers of serum anti-myelin antibodies; and (4) signs of macrophage activation in the serum. Plasmapheresis may be a successful treatment for the type of inflammatory demyelination shown in the present case.