HLA-DRB1 and systemic lupus erythematosus: Further analysis of the association of HLA-DRB1*04 with clinical and biological factors showed that it had a significant correlation with the Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) scores, C-reactive protein (CRP) in the blood, anti-nuclear antibody (ANA), and total protein in the urine.