ABCB4 and primary biliary cholangitis: As shown in Fig. 1, the ABCB4 c.711A > T polymorphism modulated serum AST (P = 0.018, Fig. 1A), ALP (P < 0.001, Fig. 1B), GGT (P = 0.003, Fig. 1C) in the PBC patients from Szczecin and serum ALP (P = 0.021, Fig. 2A) and GGT (P = 0.045, Fig. 2B) in the PBC patients from Warsaw.