HLA-DRB5 and type 2 diabetes mellitus: Downregulation of HLA-DRB4 in peripheral blood mononuclear cells is associated with T2D as well as dyslipidemia and periodontitis (Corbi et al. 2020), while a meta-analysis revealed that the lack of HLA-DRB5 increased T2D risk (Jacobi et al. 2020).