HLA-DRB1 and type 1 diabetes mellitus: When we analysed the association of haplotypes of HLA-DRB1-DQB1 loci with IA2A positivity, we observed a significant increase in the frequency of DRB1∗04-DQB1∗03 in IA2A+ T1D patients compared to IA2A– patients (22.5% vs. 12.97%; P = 0.041; OR = 1.95; 95%CI = 1.08-3.52).