Testing histocompatibility antigens (loci A and B) in a group of type 1 (insulin-dependent) diabetic patients in Bucharest.

For a preliminary estimation of the prevalence and significance of HLA antigens, tests were carried out on the A and B loci in an unselected group of 107 patients with type 1 diabetes in Bucharest. Monospecific antisera furnished by NIH, Bethesda were used. For HLA-A the following data were obtained: A2 (20.3% of the total specificities); A1 (18.4%); A3 (14.0%); A28 (10.1%). Provisional estimations in the healthy population also indicated HLA-A2 as being more frequent than followed by A30/31, A1, A9, A3. For HLA-B: B7 (38.2%); B5, B12 and B14 (14.0% each); B8 (11.1%). In the healthy subjects, the order was B12, B35, B5, B8 the same as B18, then B7 (which did not exceed 11%). The most frequently encountered haplotypes in the diabetic patients were: A2/B7 (8.4% of the total haplotypes); A3/B7 (6.9%); A1/B7 (6.6%); A10/B7 (3.8%); A9/B7 and A11/B7 (3.6% each). An unexpectedly high frequency of the HLA-B7 antigen was found in group of diabetic patients investigated, contrasting with its assumed "protector" role in the Caucasian population. The frequency of antigen HLA-A3 and haplotype HLA-A3/B7 infringes their listing in the "resistance axis" to diabetes.