Anti-ganglioside antibodies in new onset type 1 diabetic patients and high risk subjects.

Insulin dependent (type 1) diabetes mellitus appears to be a genetically determined autoimmune disease. Gangliosides have been implicated in type 1 diabetes as antigenic determinants recognized by islet cell antibodies (ICA) and shown to be able to modulate autoimmune phenomena in experimental diabetes. In order to explore in type 1 diabetes the humoral immune reactivity against gangliosides, taking into account their pancreatic localization and molecular characteristics, antibodies to gangliosides GM3, GM2, GM1, GD3, GD1a, GD1b, and GT1b have been investigated in sera from new onset type 1 diabetics and relatives of type 1 diabetic patients with or without insulin (CIAA) and/or islet cell autoantibodies. Using a purposefully designed sensitive ELISA method we found that presence of antibodies directed against the pacreatic disialo-ganglioside GD3 in a significant percentage of newly diagnosed type 1 diabetics (p < 0.001 vs normal controls) but not in CIAA and/or ICA positive relatives of type 1 diabetics. These findings confirm the involvement of gangliosides in autoimmune phenomena related to type 1 diabetes and suggest disialo-ganglioside GD3 as target of a humoral immune response associated with the onset of insulin-dependent diabetes.