title: The glutamic acid decarboxylase 65 immunoglobulin G subclass profile differs between adult-onset type 1 diabetes and latent autoimmune diabetes in adults (LADA) up to 3 years after clinical onset.
abstract: Autoantibodies against glutamic acid decarboxylase 65 (GADA) are found frequently in patients with autoimmune diabetes. Immunoglobulin (Ig)G(1) is the most frequent subclass among the GADA IgG subclasses. IgG(4) is a more common subclass in latent autoimmune diabetes in adults (LADA) at clinical onset compared to type 1 diabetes. The aim of this work was to study the different GADA-IgG subclass profiles during a 3-year follow-up in these groups of autoimmune diabetes. Adult-onset subjects, classified as either type 1 (n = 40) or LADA (n = 43), were included in the study. New samples were collected every year from these patients. In addition to conventional GADA analyses, GADA-IgG subclasses were also analysed with a radioimmunoprecipitation assay using biotin-conjugated antibodies (directed against human IgG subclasses and IgM) and streptavidin Sepharose. During 3 years' follow-up, all the IgG subclass levels decreased in type 1 diabetes - IgG(1): P < 0.001; IgG(2): P < 0.001; IgG(3): P < 0.001; IgG(4): P < 0.05 (Friedman's' test) - while levels remained stable for all four subclasses in LADA. GADA IgM, however, decreased in both groups (P < 0.001). Patients with LADA have higher GADA IgG(3) and IgG(4) at clinical onset and seem to maintain the levels and profile of their IgG subclasses up to 3 years after clinical onset, while all the GADA IgG subclass levels decrease in type 1 diabetic patients. This indicates a persistent different immune response in LADA compared to type 1 diabetes and further indicates the difference in pathogenesis.
authors: Department of Clinical Sciences, Lund University, Lund, Sweeden. magnus.hillman@med.lu.se
authors: M
authors: M
authors: Hillman
authors: C
authors: C
authors: Törn
authors: M
authors: M
authors: Landin-Olsson
mesh_terms: D000293:Adolescent; D000328:Adult; D017668:Age of Onset; D000368:Aged; D001323:Autoantibodies / Q000145:classification* / Q000276:immunology; D002096:C-Peptide / Q000032:analysis; D003922:Diabetes Mellitus, Type 1 / Q000276:immunology*; D005260:Female; D005500:Follow-Up Studies; D005968:Glutamate Decarboxylase / Q000276:immunology*; D006801:Humans; D007074:Immunoglobulin G / Q000032:analysis / Q000145:classification*; D007075:Immunoglobulin M / Q000032:analysis; D008297:Male; D008875:Middle Aged; D015531:Radioimmunoprecipitation Assay; D018709:Statistics, Nonparametric; D055815:Young Adult
chemical_list: D001323:Autoantibodies; D002096:C-Peptide; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D005968:Glutamate Decarboxylase