HLA-DRB1 and primary biliary cholangitis: Our identification of amino acids in HLA-DPβ1 and HLA-DRβ1 as the top contributors to HLA-induced PBC risk is consistent with the results of Invernizzi et al. [22] who found in their (much smaller) Italian data set that conditioning on residue L at position 11 of HLA-DPβ1 largely removed the signal at HLA-DPB1, and who noted that, considered together, HLA-DRB1*08 and HLA-DPB1*03:01 accounted for the majority of the signal in the HLA region.