The fine structure of the cns in multiple sclerosis. II. Vesilcular demyelination in an acute case.

Tubular vesicular and net-like dissolution of myelin sheaths associated with complete demyelination and preservation of axons, is described in the brain, obtained within 4 h of death, from a patient who died with acute multiple sclerosis (MS). It was rare, being found in only three out of twenty-three blocks examined, and was seen mainly in the partially demyelinated margin of an active plaque in the white matter. The possibility that post-mortem autolytic changes or fixation artefact might have accounted for the appearances is considered, but is thought unlikely. The findings, though not specific would be expected if current theories invoking myelin-directed 'autoimmune' mechanisms in MS pathogenesis are correct. However, other myelin-directed mechanisms cannot be excluded on the basis of this evidence alone.