HLA-DRB1 and temporal arteritis: In our UK data (225 cases and 1378 controls), HLA-DRB1*04 carriage was associated with GCA susceptibility (odds ratio (OR) = 2.69, P = 1.5×10−11), but HLA-DRB1*01 was protective (adjusted OR = 0.55, P = 0.0046).