HLA-DRB1 and IgA glomerulonephritis: HLA-DRB1/DRB5 rs660895*G allele is associated with increased risk of rheumatoid arthritis (RA) in Europeans and Asians (42), IgA nephropathy in Asians (43), while the decreased risk of ulcerative colitis and inflammatory bowel disease (IBD) (44).