This study will explore why severe scarring of the liver (cirrhosis) develops so rapidly in hepatitis C-infected patients who have had a liver transplant and possibly in kidney transplant patients as well. The hepatitis C virus (HCV) can cause cirrhosis in about 20 percent of infected persons. Generally, it takes 20 years or more for cirrhosis to develop. After liver transplantation, however, patients may develop cirrhosis in as little as 5 years. Cirrhosis does not develop as rapidly in kidney transplant patients, but it may develop faster than in people who do not undergo transplantation. The study will look at the possible role of immune-suppressing medications given to liver and kidney transplant patients in increasing the severity of hepatitis C infection and in speeding the cirrhotic process.