The autoimmune background of PBC is indicated by the location of PBC-related single nucleotide polymorphisms (SNPs) in genes encoding molecules of the immune system (i.e., Human Leukocyte Antigens (HLA) class II, Il-12A, and Signal Transducer And Activator Of Transcription 4 (STAT4)) [39,40]. Here, STAT4 is linked to primary biliary cholangitis.