title: Humoral autoimmune responses to glutamic acid decarboxylase have similar target epitopes and subclass that show titer-dependent disease association.
abstract: Glutamic acid decarboxylase (GAD) is an autoantigen in stiff man syndrome (SMS) and type 1 diabetes (T1DM). Different GAD autoantibody characteristics in these disorders have suggested distinct underlying mechanisms of autoimmunity. Here, it is shown that increased prevalence of autoantibodies to GAD65 amino terminal and GAD67 epitopes and autoantibodies of IgG2, IgG3, or IgG4 subclass in patients with SMS (P < 0.001 vs. T1DM) are secondary to the markedly higher autoantibody titers in SMS patients (P < 0.0001) and that autoantibody epitopes and subclasses were similar when patients were matched for autoantibody titer. Exposure to autoantigen in the disorders is likely to involve similar humoral antigenic determinants, but different B cell regulation.
authors: Immunology of Diabetes Unit, Istituto Scientifico San Raffaele, Milan, Italy.
authors: Sandra
authors: S
authors: Piquer
authors: Cristina
authors: C
authors: Belloni
authors: Vito
authors: V
authors: Lampasona
authors: Elena
authors: E
authors: Bazzigaluppi
authors: Marika
authors: M
authors: Vianello
authors: Bruno
authors: B
authors: Giometto
authors: Emanuele
authors: E
authors: Bosi
authors: Gian Franco
authors: GF
authors: Bottazzo
authors: Ezio
authors: E
authors: Bonifacio
mesh_terms: D000917:Antibody Formation; D000918:Antibody Specificity / Q000276:immunology; D001323:Autoantibodies / Q000097:blood* / Q000276:immunology; D003922:Diabetes Mellitus, Type 1 / Q000150:complications / Q000276:immunology*; D018985:Epitopes, B-Lymphocyte; D005260:Female; D005968:Glutamate Decarboxylase / Q000276:immunology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D016750:Stiff-Person Syndrome / Q000150:complications / Q000276:immunology*
chemical_list: D001323:Autoantibodies; D018985:Epitopes, B-Lymphocyte; D005968:Glutamate Decarboxylase