To determine whether the G-PBC transplant recipients developed a humoral antibody response to the newly expressed human BDDFVIII, canine blood plasma (from F20, I42 and M64) was screened for inhibitors with an activated partial thromboplastin time (aPTT) mixing assay that detects inhibitory antibodies to either coagulation factor VIII or IX. Here, F8 is linked to primary biliary cholangitis.