HLA-DRB1 and rheumatoid arthritis: However, HLA-DRB1*04, which is carried by 67–78% of anti-CCP-positive RA patients (10–12), correlates more strongly with anti-CCP-positive RA than HLA-DRB1*01 (reported in 22–51% of anti-CCP-positive RA patients) (10–12).