Islet-cell cytoplasmic antibodies in Japanese diabetics

Islet Cell-Cytoplasmic Antibodies (ICA) in serum samples obtained from 616 Japanese diabetics were examined. The patients included 296 subjects with insulin-dependent diabetes (IDDM) and 320 with noninsulin dependent diabetes (NIDDM). The number of ICA-positive cases found in 96 subjects in whom the duration of IDDM was under one year was found to be 50% (48/96), though in subjects with a duration over one year, it was only 14.5% (29/200). The prevalence of ICA-positive cases in the NIDDM group was 2.2% (7/320), and none of the nondiabetics had ICA in their serum. Moreover, none of 45 first-degree relatives of 19 patients with IDDM of whom 5 were positive and others were negative for ICA had ICA. Concerning the relationship between HLA-type and ICA in IDDM, there was a tendency for the prevalence of BW54, DR4 and MT3 of HLA to be higher in the ICA-negative group than in the ICA-positive group or the non-diabetic group. In 28 patients with IDDM, both ICA and ICSA were checked. Of 21 patients positive for ICA, only 3 had ICSA, although 3 out of 7 patients with negative ICA were positive for ICSA. Therefore no correlation was found between ICA and ICSA.