Genetic susceptibility in diabetes mellitus: analysis of the HLA association.

Two hundred and eighty-eight patients with insulin-dependent diabetes w,o were aged 30 or under at onset and 150 patients with late-onset diabetes, 50 of them dependent on insulin and 100 not dependent on insulin, were HLA-typed. There was a significant positive association between the young-onset insulin-dependent patients and HLA-B8, BW15, and B18 and a significant negative association with B7. These data were combined with those from two other centres. There was a significant concordance for the distribution of all the HLA antigens among these three series, producing evidence in favour of an HLA-linked diabetogenic gene (or genes) having a major role in all cases of juvenile-onset insulin-dependent diabetes. There was a positive association between late-onset insulin-dependent diabetes and B8, but no association between non-insulin-dependent diabetes and the HLA system. This provides further evidence for the existence of different pathogenetic mechanisms in the two major clinical forms of diabetes mellitus.