Prevalence of cytoplasmatic islet cell antibodies and insulin autoantibodies is increased in subjects with genetically defined high risk for insulin-dependent diabetes mellitus

Abstract
The presence of cytoplasmatic islet cell antibodies (ICA) and IgG insulin autoantibodies (IgG-IAA) has been observed in the prediabetic state of type 1 (insulin-dependent) diabetes (IDDM). We therefore analyzed the prevalence of these markers in sera from 1117 healthy HLA-typed first-degree relatives (1° Rel) of IDDM patients. ICA was determined by indirect immunofluorescence on cryostat sections of human pancreas. For IgG-IAA measurement a competitive solid-phase ELISA was used. ICA were present in 3.5% of 1° Rel vs 0.4% of controls (PPPPn=810) tested for both antibodies. IgG-IAA occurred in 6/35 (17%) ICA positive 1°Rel, while ICA were found in 6/79 (8%) IgG-IAA positive relatives.