FREQUENCY OF ISLET CELL ANTIBODIES IN ADULT NEWLY DIAGNOSED DIABETIC-PATIENTS

The sera of 138 Saudi patients with newly diagnosed diabetes (age, 24 to 75 years) were tested for islet-cell autoantibody (ICA), complement-fixing islet cell antibody (CF-ICA), and thyroid, stomach, and antinuclear autoantibodies. The autoantibody tests were also done on 70 nondiabetic normal control subjects matched for age, sex, and weight. Total ICA tests were positive in 13% (18/138) of the diabetics above age 35 years. Six of these sera also fixed complement. A significant incidence of ICA in each subgroup was noted in the following age ranges: 35-44 (12.8%), 45-54 (14.3%), and above 60 years (29.4%). Moreover, the incidence was higher in females (8.7%; 12/138) than in males (4.3%; 6/138). These differences were significant (P<0.001). Control group subjects were all ICA negative. In relation to age at onset above 35 years, Saudi adult diabetics appeared to be characterized by the ICA marker, indicating ongoing beta cell damage and possible subsequent insulin dependency. Thyroid, gastric parietal cell, and antinuclear autoantibodies were absent in the ICA-positive patients but were present in 36.6% (44/120) of the diabetic ICA-negative subjects as well as in 45.7% (32/70) of the control subjects. This absence of other organ-specific antibodies in ICA-positive subjects could be due to an altered immunological state produced by many parasitic infections.