Survival of oligodendrocytes in chronic relapsing experimental autoimmune encephalomyelitis.

Demyelinated plaques of chronic relapsing experimental autoimmune encephalomyelitis (EAE) have been examined in Strain 13 guinea pigs. Oligodendrocytes could be identified within these lesions adjacent to naked axons and astrocytic processes. Oligodendrocytes were identified both ultrastructurally and immunocytochemically. Many of these cells showed bizarre shapes and myelin within their cytoplasm. The survival of oligodendrocytes within these lesions suggests that the myelin sheath, not the oligodendrocyte, is the primary target in autoimmune demyelination. A similar sequence of events has been proposed in multiple sclerosis, for which chronic relapsing EAE serves as a laboratory model. The persistence of myelinating cells in areas of chronic demyelination and gliosis might have significant reparatory implications.