HLA A, B, C and DR antigens in young South African Indians with insulin-dependent diabetes mellitus.

The HLA status of South African Indian insulin-dependent diabetic patients in whom the age of onset of diabetes was under 35 years was compared with that of a group of healthy Indian controls. HLA A, B and C antigens were determined in 68 patients and 760 controls, while DR specificities were determined in 35 patients and 235 controls. The diabetic patients showed a significant increase in the frequencies of HLA B8 (19,1% v. 6,8%; relative risk 3,2; corrected P less than 0,04) and Aw24 (42,6% v. 26,8%; relative risk 2,2; corrected P less than 0,04) antigens compared with controls. HLA DR3 was found to be much more common in patients than in controls (31,4% v. 12,8%; relative risk 3,1; corrected P less than 0,035), but DR3/DR4 heterozygosity was associated with a much greater relative risk (7,25). Among patients of North Indian origin a strong association with DR4 was seen (45,5% v. 9,1% (controls); relative risk 8,3).