Immunological abnormalities associated with liver disease: cause or effect?
Immunological abnormalities are demonstrable in patients with various types of liver damage. These may be (a) non-specific and unrelated to pathogenesis, e.g. auto-antibodies such as anti-nuclear factor; (b) specifically directed against liver antigens but not pathogenetic, e.g. cell mediated immune (CMI) reactions to liver antigen as seen in experimental carbon tetrachloride poisoning; (c) of such a nature as to modify the pathology produced by hepatotoxic agents, e.g. hepatitis B virus or alcohol; (d) primarily responsible for hepatic pathology, e.g. in idiopathic chronic active hepatitis. The latter two possibilities remain unproven although there is growing evidence that immune responses do play some role in the pathogenesis of acute and chronic hepatitis B and possibly also in the pathogenesis of alcoholic liver disease. It seems much less likely that primary abnormalities of the immune systems are responsible for any type of liver disease. In summary, therefore, the available evidence suggests that immune reactions could develop as a consequence of liver damage and only in certain circumstances do these reactions play a role in the development and continuation of hepatic pathology.