gq1b-ganglioside and Disorders-of-Excessive-Somnolence

Anti-GQ1b antibodies have been found in patients with Miller Fisher syndrome as well as its related conditions. Our aim was to identify the mechanism by which autoantibodies produce various clinical presentations in 'anti-GQ1b antibody syndrome'.. Immunoglobulin G antibodies to ganglioside complex (GSC) of GQ1b or GT1a with GM1, GD1a, GD1b or GT1b were tested in sera from patients with anti-GQ1b (n = 708) or anti-GT1a (n = 696) IgG antibodies. Optical densities of the single anti-GQ1b or anti-GT1a antibodies were used as reference (100%), and those of anti-GSC antibodies were expressed in percentages to reference. The relationships between anti-GSC antibody reactivity and the corresponding clinical features were assessed by multivariate logistic regression analysis.. Ophthalmoplegia and hypersomnolence were significantly associated with complex-attenuated anti-GQ1b and anti-GT1a antibodies. Ataxia was associated with GD1b- and GT1b-enhanced anti-GQ1b antibodies or GM1-enhanced anti-GT1a antibodies. Bulbar palsy was associated with GT1b-enhanced anti-GQ1b antibodies. Neck weakness was associated with GD1a-enhanced anti-GQ1b antibodies. Arm weakness was associated with GD1b-enhanced anti-GQ1b and GD1a-enhanced anti-GT1a antibodies. Leg weakness was associated with GD1a-enhanced anti-GQ1b and anti-GT1a antibodies.. Differences in fine specificity of anti-GQ1b antibodies are associated with clinical features, possibly due to the different expression of gangliosides in different parts of the nervous system.

Topics: Ataxia; Autoantibodies; Bulbar Palsy, Progressive; Disorders of Excessive Somnolence; Gangliosides; Guillain-Barre Syndrome; Humans; Immunoglobulin G; Miller Fisher Syndrome; Muscle Weakness; Ophthalmoplegia

Clinical and immunological evaluation of 'incomplete' Bickerstaff brainstem encephalitis (BBE).. We studied two patients with postinfectious brainstem syndromes who presented at National University Hospital Singapore. Laboratory work-up included measurement of antiganglioside antibodies.. Both patients displayed hypersomnolence and cerebellar-like ataxia in the absence of external ophthalmoplegia and carried high serum titres of IgG anti-GQ1b antibodies, strongly indicative of BBE.. Ophthalmoplegia can be absent or incomplete in BBE, and the absence of this clinical feature should not exclude BBE from the clinicians' differential. Such cases of incomplete BBE could be defined as 'ataxic hypersomnolence without ophthalmoplegia'.

Topics: Adult; Autoantibodies; Brain Stem; Cerebellar Ataxia; Disorders of Excessive Somnolence; Encephalitis; Female; Follow-Up Studies; G(M1) Ganglioside; Gangliosides; Humans; Immunization, Passive; Middle Aged; Neurologic Examination; Ophthalmoplegia

Topics: Adult; Autoantibodies; Brain Stem; Cerebellar Ataxia; Disorders of Excessive Somnolence; Encephalitis; Female; Gangliosides; Guillain-Barre Syndrome; Humans; Immunoglobulin G; Intracellular Signaling Peptides and Proteins; Mental Status Schedule; Neurologic Examination; Neuropeptides; Ophthalmoplegia; Orexins