FGF19 and primary biliary cholangitis: Additionally, studies revealed that the expression of FGF19 in the liver tissue of patients with biliary atresia or PBC was significantly higher than FGF19 in serum, suggesting that intrahepatic auto-/paracrine FGF19 feedback signaling might exist (Al-Khaifi et al. 2018; Nyholm et al. 2023).