Interestingly, certain alleles of HLA-DRB1 are also determinants of SLE autoantibodies and phenotypes, e.g., HLA-DRB1*03 associates with anti-SSA/Ro60/Ro52/SSB autoantibodies and frequently manifests as discoid lesions in SLE, HLA-DRB1*15 is associated with anti-nucleosome/SmRNP/DNA/RNPA autoantibodies and manifests in the form of lupus nephritis, whereas HLA-DRB1*04 is associated with anti-β2GPI-IgG/anti-CL–IgG/IgM autoantibodies and often occurs in the form of vascular lesions [37]. Here, TRIM21 is linked to systemic lupus erythematosus.