HLA-DRB1 and lupus nephritis: Similarly, the absence of an association of HLA-DRB1, HLA-DQB1, and HLA-DQA1 alleles with renal involvement in our cohort may represent a power issue for HLA-DRB1*15 (HLA-DR2) and other alleles previously reported to be associated with lupus nephritis [17,29].