HLA DR antigens in adult-onset and juvenile-onset Japanese insulin-dependent diabetic patients.

In order to discover the HLA DR antigens linked to Japanese insulin-dependent diabetes (IDDM), and to relate them to the clinical features, HLA DR antigens were examined in 75 IDDM patients including 56 adult-onset cases. Among the tested HLA DR antigens, 4, w9 and w13 were significantly more frequent in IDDM (55%, 47% and 27% respectively). The relative risk was 1.71 for DR4, 2.81 for DRw9 and 4.74 for DRw13. DR2 was significantly less frequent and the relative risk was 0.14. The distribution of DR antigens did not differ between juvenile-onset and adult-onset IDDM, males and females, or cases with and without thyroid autoantibodies. Homozygotes for DRw9 were, but those for DRw13 and DR4 were not more frequent than expected by a random combination. Heterozygotes for DR4 and w9 were less frequent while other heterozygotes for high-risk antigens were as frequent as expected. 97% of IDDM had either DR4, w9 or w13. In conclusion, HLA DR4, w9 and w13 were significantly increased in patients with both juvenile- and adult-onset IDDM. There was no surplus increase in the frequency of IDDM patients with two high-risk HLA DR antigens, more than expected from random combination of each of these DR antigens. Clinical features did not differ among IDDM patients with each of these three antigens.