What is overlap AIH syndrome?

7% of AIH overlap w/PBC (primary biliary cirrhosis) (detectable AMA, histo injury of bile duct, may improve w/steroids) 6% of AIH overlap w/PSC (primary sclerosing cholangitis) (concurrent IBD, liver biopsy shows bile duct injury, abnormal cholangiograms, mixed hepatocellular and cholestatic liver chemistries, resistant to steroids, tx w/ ursodiol)