HLA-DRB1 and systemic lupus erythematosus: The genotyping of the HLA regions (HLA-A, HLA-B, HLA-C, HLA-DPB1, HLA-DRB1 and HLA-DQB1) in the four primary samples was also performed (Figure S11), and all of these loci were heterozygous except for HLA-DRB1*15:01:01 and HLA-DQB1*06:02:01 in SLE-1.