[Islet cell antibodies].

Islet cell antibodies (ICA) are a marker of insulin-dependent diabetes mellitus (IDDM). ICA are detected in 60-80% of the patients with IDDM at the onset of the disease. The presence of ICA in patients with non-insulin-dependent diabetes mellitus (NIDDM) indicates that the patients are likely to develop IDDM. However, as ICA are measured by the indirect immunofluorescent method, the reliability of the ICA assay is not high in some institutes. Use of the pancreas tissue having high antigenicity is recommended as one solution for a reliable assay. Standardization of the ICA assay is under way with the use of an ICA positive standard sera as 80 JDF units. Anti-glutamate decarboxylase (GAD) antibody assays using a radioimmunoassay (RIA) or enzyme-linked immunosorbent assay (ELISA) have recently been developed. The significance of anti-GAD antibodies is comparable to that of ICA. Since the anti-GAD assay is reproducible and easy to perform, it should be used widely in parallel with the ICA assay.