Two types of autoantibodies to adrenal medullary cells in type 1 (insulin-dependent) diabetic patients: prevalence, properties and implications.

Complement-fixing adrenal medullary antibodies were examined in sera from 170 (114 Type 1 and 56 Type 2) diabetic patients and normal subjects by indirect immunofluorescence methods. Two types of antibodies were detected; one showed a homogeneous immunofluorescence pattern (homogeneous-type) and the other a spotty pattern (spotty-type) in the cytoplasm of adrenal medullary cells. Both antibodies were IgG class and adrenal medulla-specific. The prevalence of the homogeneous-type was significantly higher in Type 1 diabetic patients with disease duration under 1 year (36%) than in those with duration of 1 year or more (1.1%), in Type 2 diabetic patients (1.8%) or in normal subjects (0%; P less than 0.01). Conversely, the prevalence of the spotty-type was not significantly different among all subjects examined (3.6-4.5%). The epitope for the homogeneous-type is likely to be a glycoconjugate since binding of this antibody was abolished after periodate oxidation. The epitope for spotty-type antibody is considered to be a peptide since it was trypsin sensitive. Patients who were positive for the homogeneous-type were also positive for islet cell antibodies, although their antibody titers were not correlated. We conclude that (1) adrenal medullary antibodies are of homogeneous-type or spotty-type and the antigenic determinants of these antibodies are different, and (2) the prevalence of the homogeneous-type is significantly higher in newly diagnosed Type 1 diabetic patients and its presence is associated with that of islet cell antibodies.