The current endeavors to understand the pathogenesis of intractable liver diseases

The death due to liver diseases accounts for more the 35,000 cases every year in Japan for decades. Among these liver diseases, the Ministry of Health, Labor, and Welfare of Japan has named both fulminant hepatitis and primary biliary cirrhosis (PBC) as intractable liver diseases, since the precise mechanism of these diseases are unclear. Accordingly, there are no effective medical treatments other than liver transplantation toward these diseases. However, still the number of the liver transplantation performed in Japan is small. Thus, we have focused on the pathogenesis of these two intractable conditions. The fulminant hepatitis is a distinct form of acute hepatitis, and hepatitis B virus infection accounts for 20~30% of this lethal condition. Only tiny proportions of patients with acute HBV infection develop fulminant hepatitis (less than 10%). It has been widely believed both viral and host factors contribute for fulminant hepatitis, although still unknown factors are expected to be involved. On the other hand, PBC is a chronic progressive cholestatic liver disease. Clinical features of PBC include female predominance (80 to 90%), the presence of antimitochondrial antibody (up to 95%), and elevated serum levels of immunoglobulin M. Eventually, patients with PBC will develop liver failure due to biliary cirrhosis in spite of medical interventions. Immune-mediated processes are believed to be responsible for the pathogenesis, although the precise mechanism is yet to be determined. In this review article, our endeavors to understand the mechanism of these intractable liver diseases are discussed.