Islet-cell antibodies in IDDM and NIDDM in a Japanese population

Islet-cell antibodies (ICA) were studied in 538 Japanese diabetics with insulin-dependent diabetes mellitus (IDDM) and non-insulin-dependent diabetes mellitus (NIDDM). The overall prevalence of ICA was 17% (16/93), 4% (7/164), 2% (2/90) and 3% (5/191) in IDDM, NIDDM treated with insulin, NIDDM treated with oral hypoglycemic agents, and NIDDM treated by diet alone, respectively. ICA were detected in 58% (11/19) of patients with IDDM in the first year of the disease. The prevalence of ICA decreased drastically with prolongation of the disease. We could not find any ICA-positive IDDM in subjects with a clinical course of more than 10 years. The level of thyroid microsomal antibodies was not significantly higher in either type of diabetes when compared to nondiabetic controls. These results suggest that Japanese diabetics may have a weaker autoimmune predisposition than Caucasians.