HLA antigens in insulin dependent and non-insulin dependent Spanish diabetic patients.

HLA-A, -B, -C, -DR and Bw4, Bw6 antigens and Bf and GLO alleles have been studied in a sample of Spanish insulin dependent (IDD) and non-insulin dependent (NIDD) diabetic patients. In IDD's there was no significant increase of B8 and B15; an increase of B18 secondary to that of DR3 has been found. DR4 was also increased in our sample. The GLO-S/DR2 haplotype was found to be decreased in IDD. It was observed that (Aw30)-B18-Cw5-Bw6-DR3-BfF1 is the commonest ID diabetic haplotype in our population. A relationship between DR4 and early IDD onset was also found. No association was found between HLA, or Bf, and age of onset, macroangiopathy, microangiopathy, retinopathy, nephropathy and peripheral or autonomic neuropathy. In NIDD's, DR3 was increased and DR3-non BfF1 and DR3-non B18 RRs were higher than DR3 RR.Aw30 and Cw5 tended to be decreased, although not significantly. These findings further support the hypothesis that several closely linked diabetic susceptibility factors may exist within an HLA haplotype (i.e.: (Aw30)-B18-Cw5-Bw6-DR3-BfF1 in our population) and that all of them may be necessary for developing an IDD form; lack of one or several factors might lead to the acquisition of the NIDD form.