HLA-DRB1 and rheumatoid arthritis: The HLA region was suggestive of pleiotropy between RA and CRP, specifically genes HCP5/MICB and region HLA-DRB1/HLA-DQA1. RA with high inflammatory markers in the presence of HLA-DRB1 alleles was shown to have a greater risk of cardiovascular complications (29) and increased disease severity of RA (30).