HIV-Related Neurological Disease in the Era of HAART

Abstract

Guillain-Barré syndrome (GBS) comprises a group of clinically and pathophysiologically related acute monophasic neuropathic disorders, likely of autoimmune origin, with an incidence of 1-1.5 per 100,000 population per year (1-3). After the near eradication of polio, GBS has become the commonest cause of acute flaccid paralysis throughout the world. It is now widely accepted that GBS encompasses demyelinating and axonal forms, as well as the Fisher syndrome (FS) and other minor variants. Advances made over the last 15 years indicate that (a) GBS is pathophysiologically heterogeneous, and (b) post-infectious autoimmunity is probably the predominant pathophysiologic mechanism in some forms of GBS. Post-infectious molecular mimicry in the peripheral nervous system (PNS) implies shared antigenic determinants between the infectious agents and nerve fibers of the PNS. This results in an immune response to the organism that initiates immune-mediated damage to nerve fibers. The support for this concept derives largely from both clinical and experimental studies on the acute motor axonal neuropathy (AMAN) and Fisher variants of GBS. In this context the most commonly recognized antecedent infection is Campylobacter jejuni enteritis. Specific anti-ganglioside antibodies are associated with different variants ofGBS. The lipooligosaccharides (LOSs) of C. jejuni isolates from patients with GBS carry relevant ganglioside-like moieties and gangliosides, the purported target antigens, are enriched in the nerve fibers. Pathological studies in the AMAN variant of GBS show antibody-mediated, complement-dependent injury of nerve fibers, supporting the important pathogenetic role of antibodies in the axonal variants of GBS.