FIGURE 26.

Immunopathogenesis of the AMAN form of Guillain-Barré syndrome. Gangliosides GM1 and GD1a are strongly expressed at nodes of Ranvier, where the voltage-gated sodium (Nav) channels are localized. Anti-GM1 or anti-GD1a antibodies bind to the nodal axolemma, leading to formation of the complement membrane attack complex (MAC). This results in the disappearance of Nav clusters and the detachment of paranodal myelin, which can lead to nerve-conduction failure and muscle weakness. Axonal degeneration may follow at a later stage. Macrophages subsequently invade from the nodes into the periaxonal space, scavenging the injured axons. [Adapted from Yuki and Hartung (577), with permission from Massachusetts Medical Society.]