HLA-DRB1 and systemic lupus erythematosus: Iterative conditional analysis identified six residue positions independently associated with SLE: HLA-DRB1-13/11 and 37 (Pconditional = 6.8x10-27); HLA-A-70 (P = 8.9x10-8), HLA-DPB1-35 (P = 1.4x10-6), HLA-DQB1-37 (P = 7.2x10-7), and HLA-B-9 (P = 4.5x10-5) (Table 1).