Ultrastructural study of peripheral nerve in Guillain-Barré syndrome presence of mononuclear cells in axons.

As has been shown during the course of experimental allergic neuritis, in the Guillain-Barré syndrome there is an invasion of the myelin sheath in certain fibres by a mononuclear cell, with an intact axon. In a series of 45 cases we have been able to show this feature in 31 cases. In certain cases the cytoplasm prolongation of the invading cell was seen in the myelin sheath, forcing apart two neighbouring layers. In five cases we have furthermore observed the presence of mononuclear cells located either between the myelin and the axon which is deformed, or on the inside of the axon. Such an anomaly was frequent in one recent case and was occasionally found in four other cases.