- Cystic fibrosis-associated liver disease, defined by at least one of the following criteria: (1) Documented increase in serum concentrations of any of the liver enzymes (at least once in the preceding year) ALT at least twice normal AST at least 1.5 times normal Alkaline phosphatase at least 1.5 times normal GGT at least 1.5 times normal (2) Persistent hepatomegaly of more than 6 months duration defined by percussed liver span greater than 1 SEM for age (3) Splenomegaly, defined as a palpable spleen greater than 2.0 cm below the left costal margin (4) Abnormalities of ultrasound scan (increased size, dishomogeneous echogenicity, nodular liver, irregular margins, splenomegaly) within 6 months prior to study entry