Patients with insulin-dependent diabetes but not those with non-insulin-dependent diabetes have anti-sulfatide antibodies as determined with a new ELISA assay

Background : In sera from newly diagnosed insulin-dependent diabetes mellitus patients (IDDM type 1) autoantibodies occur against different antigen determinants often shared with neural tissues. The role of these autoantibodies in the disease process is not yet clarified but they can be used as a diagnostic tool in the detection of IDDM patients. Methods : We have analysed the occurrence of sulfatide autoantibodies in serum from patients with type 1 diabetes (n=20), individuals with pre-type 1 diabetes (n=6), patients with type 2 diabetes (n=32) and controls (n=43). The method used for the determination of the autoantibodies was a newly developed microtitre-ELISA assay utilizing a complex of sulfatide-albumin as the ligand. Results : The new assay procedure for serum sulfatide autoantibodies showed good reproducibility. The total (day-to-day) imprecision based on analyses of three different serum samples with positive titres varied between 11 and 14% during an assay period of 6 months. None of the controls (0/43) had positive titres of sulfatide antibodies. Of the patients with type 1 diabetes, 85% displayed positive titres of anti-sulfatide antibodies while none of the type 2 patients did so. All individuals with pre-type 1 diabetes had positive titres of sulfatide antibodies. Conclusions : We conclude that sulfatide autoantibodies in serum can be reproducibly assayed by the newly developed microtitre-ELISA procedure. Elevated titres of sulfatide autoantibodies are a constant finding in newly diagnosed type 1 patients.