Correlations between insulin antibodies and the HLA system in a group of type I diabetic patients in Bucharest

Investigations were carried out in Bucharest in 102 patients with insulin-dependent diabetes mellitus (IDDM) in order to verify the possible existence of a relationship between the HLA system and the level of insulin antibodies. The A and B loci were tested with monospecific antisera, using PEC as a separation agent for the determination of the insulin antibody titer. Group I, without antibodies (34 cases), presented: HLA-B7 (18.89% of total specificities), A3 (11.02%), A1 and B5 (8.74% each), etc.: for haplotypes the following were found: HLA-A3/B7 (9.91% of the total haplotypes), A2/B7 (8.26%), A1/B7 (5.78%). Group II (50 cases) with low or medium titers (less than 30% binding) included: HLA-B7 (20.47%), A2 (11.88%), (A1 (9.44%), B5 (8.74%), and haplotypes: HLA-A2/B7 (8.88%), A1/B7 (7.22%), A3/B7 (6.11%). Group III (18 cases), with high antibody titers (greater than 30% binding), presented: HLA-B7 (20.28%), A1 and A2 (11.59% each), A10 (10.14%), and haplotypes: HLA-A1/B7 (10.60%), A2/B7 and A10/B7 (9.09% each), A3 B7, A2 B5 and A10/B5, (6.06% each). Irrespective of the insulin antibody titer, B7 antigen surprisingly appeared predominant in our cases. Moreover, a marked tendency of A1, and to a certain extent of A2, to increase in terms of the titer was noted in parallel with a significant decrease of A3.