HLA class I and II alleles are associated with microvascular complications of type 1 diabetes.

Although HLA alleles are associated with type 1 diabetes, association with microvascular complications remains controversial. We tested HLA association with complications in multiplex type 1 diabetes families. Probands from 425 type 1 diabetes families from the Human Biological Data Interchange (HBDI) collection were analyzed. The frequencies of specific HLA alleles in patients with complications were compared with the frequencies in complications-free patients. The complications we examined were: retinopathy, neuropathy, and nephropathy. We used logistic regression models with covariates to estimate odds ratios. We found that the DRB103:01 allele is a protective factor for complications (OR=0.58; p=0.03), as is the DQA105:01-DQB102:01 haplotype found in linkage disequilibrium with DRB103:01 (OR=0.59; p=0.031). The DRB104:01 allele showed no evidence of association (OR=1.13; p=0.624), although DRB104:01 showed suggestive evidence when the carriers of the protective DRB103:01 were removed from the analysis. The class II DQA103:01-DQB103:02 haplotype was not associated with complications, but the class I allele B39:06 (OR=3.27; p=0.008) suggested a strong positive association with complications. Our results show that in type 1 diabetes patients, specific HLA alleles may be involved in susceptibility to, or protection from, microvascular complications.