Islet cell antibodies, circulating immune complexes and antinuclear antibodies in diabetes mellitus

Serum samples of patients suffering from diabetes mellitus were tested for complement-fixing and non complement-fixing islet cell antibodies, antinuclear antibodies and circulating immune complexes. There was no correlation between circulating immune complexes or antinuclear antibodies and secondary diabetic complications. A close relationship was found between the ICA titer and complement fixation of ICA. The incidence of ICA at the onset of the disease was higher in the patients under the age of 10 (85%) and decreased with increasing age up to 45% in patients with onset above age 20. In five patients being positive and four patients being negative for ICA at onset of disease, changes and fluctuations in antibody titers were observed over 38 months. Since manifestation of diabetes mellitus is believed to be an endpoint of a long lasting autoimmune process, our observations indicate that the autoimmune phenomena are merely indicators of ongoing autoimmune reactions not necessarily reflecting the state of autoaggression or islet cell destruction.