Comparative analysis of HLA II allele and genotype frequency distribution in patients with type 1 diabetes mellitus and autoimmune thyroiditis

Aim.  To compare HLA II allele and genotype frequency distribution in type 1 diabetes mellitus (T1DM) and autoimmune thyroiditis (AIT) with that in isolated T1DM. Materials and Methods. A total of 92 T1DM patients were subdivided into two groups. The first group comprised 54 patients with established AIT comorbidity or elevation of anti-thyroid autoantibodies (ATA). Patients with isolated T1DM (ATA-negative) formed the second group. HLA-genotyping was performed by multiprimer PCR set for the three following genes: DRB1 , DQA1 and DQВ1 . Results.  Prevalence of alleles DRB1 *01, *03(017), *04, *07, *11 and genotypes 01/03, 01/04, 03/04 tends to be higher among patients with AIT comorbidity. The comorbidity group was also characterized by the trend towards higher prevalence of ?marker/marker? and ?marker/non-marker? combinations favouring the former variant. Conversely, ATA-negative patients exhibited trend for higher prevalence of ?non-marker/non-marker? combination. Conclusion. Statistically insignificant difference between HLA II alleles and genotypes in the two studied groups suggests that primary genetic factors are common in these two diseases. Plausibly, genes other than DRB1 , DQA1 and DQВ1 determine the localization of the autoimmune process.