HLA-DRB1 and rheumatoid arthritis: They encode a conserved amino acid sequence (QKRAA, QRRAA or RRRAA) called the shared epitope (SE) at positions 70–74 in the third hypervariable region of the HLA-DRβ1 molecule [9].There is preliminary evidence that the increased cardiovascular risk in patients with RA can be, at least partly, associated with polymorphism in the HLA-DRB1 locus [10], [11].