Several diseases including progressive familial intrahepatic cholestasis type 3 (PFIC3), low phospholipid-associated cholelithiasis (LPAC), a subgroup of patients developing intrahepatic cholestasis of pregnancy (ICP), drug-induced liver injury and chronic cholangiopathy with biliary fibrosis and cirrhosis were attributed to ABCB4 deficiency and characterized in the past decade.
In patients with severe ABCB4 genotype, the disease is often progressive with risk of developing cirrhosis and liver failure during the first 2 decades of life.
There is evidence that a biallelic or monoallelic ABCB4 defect causes or predisposes to several human liver diseases (PFIC3, low phospholipid associated cholelithiasis syndrome, intrahepatic cholestasis of pregnancy, drug-induced liver injury, transient neonatal cholestasis, adult biliary fibrosis, or cirrhosis).
Integrin beta6 mRNA increased with fibrosis stage in hepatitis C and was upregulated between 25- and 100-fold in TAA- and BDL-induced cirrhosis, in Mdr2(Abcb4)(-/-) mice and in human end-stage liver disease. alphavbeta6 protein was absent in normal livers and expressed de novo on (activated) bile duct epithelia and transitional hepatocytes.
We found no evidence for deficient or severely reduced intrahepatic MDR3 mRNA in primary biliary cirrhosis, nor were mRNA levels altered significantly by virus-induced inflammation or by cirrhosis.