[Comparison of various types of islet cell antibodies in diabetes as a function of its cause and duration].

Three types of pancreatic islet cell antibodies (ICA) have been described in insulin-dependent diabetic patients: IgG-ICA directed against cytoplasmic antigens, complement-fixing antibodies (CF ICA) and islet cell surface antibodies (ICSA) directed against membrane antigens. They can be detected by indirect immunofluorescence methods using human pancreas sections for IgG-ICA and isolate rat live islet cells for ICSA. Distribution of these 3 types of antibodies and correlations within individual patients were investigated in non-diabetic controls, in patients with idiopathic diabetes of various duration and in patients whose diabetes was associated with autoimmune diseases, chronic pancreatitis or haemochromatosis. The respective incidences of IgG-ICA and ICSA were: 5.4% and 15.8% in controls, 67.3% and 64.3% in patients with recent onset diabetes, 22.6% and 21.5% in old-standing diabetes, 63% and 50% in auto-immune diabetes, 12.5% and 7.2% in diabetes from chronic pancreatitis, and 5.6% and 7.6% in diabetes from haemochromatosis. In contrast with these correlations within groups, individual concordances were only 67%. CF ICA were relatively rare and almost exclusively present in IgG-ICA positive patients (30% of all cases); they seem to constitute a sub-group of IgG-ICA. It is concluded that IgG-ICA and ICSA are equally frequent in each type or duration of insulin-dependent diabetes and that they are not associated with secondary diabetes. The lack of concordance in individual patients indicates that the anti-pancreatic immune response is not homogeneous.