title: Anti-GM1 IgG antibodies in Guillain-Barré syndrome: fine specificity is associated with disease severity.
abstract: BACKGROUND
  Clinical severity of Guillain-Barré syndrome (GBS) is highly variable, but the immunopathological reason is unknown.
  
  
  OBJECTIVE
  The study was designed to show which antibody parameters are associated with disease severity in GBS patients with serum anti-GM1 IgG antibodies.
  
  
  METHODS
  Thirty-four GBS patients with anti-GM(1) IgG antibodies were grouped into two categories according to disease severity at nadir: mild (grades 1-3 by Hughes functional scale, n=13) and severe (grades 4 and 5, n=21). Titre, affinity, fine specificity and cell binding of anti-GM(1) antibodies were obtained and compared between the two groups.
  
  
  RESULTS
  No differences in antibody titre (GM(1)-ELISA) or affinity were found between the two patient groups. In contrast, the severe group showed a significantly higher frequency (95%, vs 46% in the mild group, p=0.002) of specific (not cross-reacting with GD(1b)) anti-GM(1) antibodies. In addition, the severe group also exhibited a higher antibody binding titre to cellular GM(1).
  
  
  CONCLUSIONS
  Differences in fine specificity of antibodies are strong indications that different regions of the GM(1)-oligosaccharide are involved in antibody binding. High titres of specific anti-GM(1) antibody binding to cellular GM(1) can be explained by antigen exposure, that is, GM(1) exposes or forms mainly epitopes recognised by specific antibodies, and 'hides' those involved in binding of cross-reacting antibodies. Thus, the fine specificity of anti-GM(1) antibodies may influence disease severity by affecting antibody binding to cellular targets. Additionally, since antibody specificity studies are relatively easy to implement, fine specificity could be considered a useful predictor of disease severity.
authors: Departamento de Química Biológica Dr Ranwel Caputto-CIQUIBIC, CONICET, Facultad de Ciencias Químicas (UNC), Ciudad Universitaria, Córdoba 5000, Argentina.
authors: Ricardo D
authors: RD
authors: Lardone
authors: Nobuhiro
authors: N
authors: Yuki
authors: Masaaki
authors: M
authors: Odaka
authors: Jose L
authors: JL
authors: Daniotti
authors: Fernando J
authors: FJ
authors: Irazoqui
authors: Gustavo A
authors: GA
authors: Nores
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001323:Autoantibodies / Q000276:immunology*; D002648:Child; D002675:Child, Preschool; D002855:Chromatography, Thin Layer; D004185:Disability Evaluation; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005677:G(M1) Ganglioside / Q000031:analogs & derivatives* / Q000276:immunology*; D005732:Gangliosides / Q000276:immunology; D020275:Guillain-Barre Syndrome / Q000276:immunology* / Q000503:physiopathology*; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D012720:Severity of Illness Index; D011795:Surveys and Questionnaires; D055815:Young Adult
chemical_list: D001323:Autoantibodies; D005732:Gangliosides; D007074:Immunoglobulin G; C064020:ganglioside GD1alpha; C033851:ganglioside, GD1b; D005677:G(M1) Ganglioside; C039129:GQ1b ganglioside