HLA-DRB1 and chronic kidney disease: The 13S residue is encoded by DRB1*13:02, DRB1*14:06, and DRB1*14:54; thus, the association of amino acid residue 13S reflects the predisposing effects of DRB1*13:02, DRB1*14:06, and DRB1*14:54 alleles for the development of CKD.