The role of the immune response in both the pathology of liver disease and in the modulation ofliver injury has been the subject of intense research. This book aims to present the current understanding of the involvement of the immune response in liver disease. The first chapters examine the role of the immune response in viral infections of the liver. These viruses cause hepatitis of varying severity and it is thought that many of the mechanisms responsible for liver cell injury are immunologically mediated. In addition three of these viruses, hepatitic B, C, and D, are associated with persistent infection and chronic liver disease. The role of the immune response in viral persistence is discussed. Further chapters are devoted to the three major autoimmune liver diseases which are thought to be the result of loss of tolerance to autologous liver tissue. There has been much recent research on cellular immune responses in these diseases but knowledge of the immunological processes which lead to the breakdown of tolerance and the mechanisms of tissue damage are limited. Other research has concentrated on the identification of the antigens which are the targets of this immune response. Linkage disequilibrium between MHC alleles and autoimmune diseases has suggested a role for immunogenetic factors.

The role of the immune response in both the pathology of liver disease and in the modulation ofliver injury has been the subject of intense research. This book aims to present the current understanding of the involvement of the immune response in liver disease. The first chapters examine the role of the immune response in viral infections of the liver. These viruses cause hepatitis of varying severity and it is thought that many of the mechanisms responsible for liver cell injury are immunologically mediated. In addition three of these viruses, hepatitic B, C, and D, are associated with persistent infection and chronic liver disease. The role of the immune response in viral persistence is discussed. Further chapters are devoted to the three major autoimmune liver diseases which are thought to be the result of loss of tolerance to autologous liver tissue. There has been much recent research on cellular immune responses in these diseases but knowledge of the immunological processes which lead to the breakdown of tolerance and the mechanisms of tissue damage are limited. Other research has concentrated on the identification of the antigens which are the targets of this immune response. Linkage disequilibrium between MHC alleles and autoimmune diseases has suggested a role for immunogenetic factors.

Howard C. Thomas In normal subjects the regulatory apparatus of the immune system permits responses to foreign antigens but suppresses those directed to "self' components. Autoimmune disease occurs as a failure ofthis system either as a result of a primary defect in the regulatory apparatus (primary autoimmunization) or because of a change in the antigenicity of the tissues (secondary autoimmunization). Autoaggressive reactions are characterised by the presence of autoantibodies. When these are directed to membrane displayed antigens (Fig. 1) they are probably of importance in the lysis of hepatocytes. Those directed to cytoplasmic antigens may be useful diagnostically but are of unknown pathogenic significance. When no extrinsic aetiological factor can be identified, the process is assumed to be the result of a failure ofthe regulatory system, allowing the spontaneous expansion of a clone of autoreactive lymphocytes. The defect may be generalised or specific to certain groups of self-antigens and thus the autoimmune disease may be either multi- or unisystemic. The recent development of techniques to enumerate and measure the functional activity of the suppressor lymphocytes which control the effector limbs of the immune system has enabled investigators to test whether the various purported autoimmune diseases do have as their basis a generalised defect in immunoregu lation. Assessment of antigen-specific immunoregulatory function is, however, not yet readily available. liver Membrane I Antigen (LIM) I Liver I HLA, A, B, C, Sensitisation to Specific -;::!IIIL. .