Figure 1.

Morphology of dermal myelinated fibers in patient 2. A skin biopsy was performed 10 cm above the left lateral malleolus. Primary antibodies to axon (protein gene product 9.5; PGP9.5), myelin (myelin basic protein; MBP), node of Ranvier (voltage gated sodium channel; Nav), paranodes (contactin-associated protein; Caspr) and secondary antibodies (Alexa Fluor dyes) were used. (A) A denuded axon flanked by myelin sheath (arrowheads) indicates a segmental demyelination. Another demyelinated segment is seen at the bottom of picture (asterisk). (B) Ongoing myelin breakdown with preserved axonal integrity (asterisk) was also noted. (C) In contrast, nodes of Ranvier and paranodes (circles) showed no abnormal dispersion or loss. The above pathological findings favored the diagnosis of acute inflammatory demyelinating polyradiculoneuropathy rather than nodal/paranodal Guillain–Barré syndrome.