Pathology of autoimmune hepatitis

Abstract

Summary Autoimmune hepatitis (AIH) is a relatively rare non-resolving chronic liver disease, which mainly affects women. It is characterized by hypergammaglobulinemia, circulating autoantibodies, interface hepatitis on liver histology and a favourable response to immunosuppression. The putative mechanism for the development of autoimmune hepatitis is thought to be the interaction between genetic predisposition, environmental triggers and failure of the native immune system. AIH still remains a major diagnostic and therapeutic challenge, mainly because it is a very heterogeneous disease. Prompt and timely diagnosis is crucial since, if left untreated, AIH has a high mortality rate. Histological demonstration of hepatitis is required for the diagnosis of AIH and, therefore, liver biopsy is mandatory in the initial diagnostic work-up, before treatment. In this review, we summarize the histological features of AIH with the main aim of highlighting the most important clinical-pathological hallmarks useful in the routine diagnostic practice.

The Translational Bridge between Inflammation and Hepatocarcinogenesis

“…Classical histological markers for AIH are the presence of a portal inflammation with eosinophilic granulocytes, plasma cell infiltrates, mainly lymphocytes in the portal tract, emperipolesis and the rosette formation of liver cells. However, all these markers can also be detected in HCV-induced chronic hepatitis [97] and are only faintly seen, or not seen, in approximately one third of the AIH cases [95]. In other recent studies, the detection of plasma cell clusters (more than five cells) in the lobulus is described as a sensitive diagnostic marker for AIH [95,97].…”

“…However, all these markers can also be detected in HCV-induced chronic hepatitis [97] and are only faintly seen, or not seen, in approximately one third of the AIH cases [95]. In other recent studies, the detection of plasma cell clusters (more than five cells) in the lobulus is described as a sensitive diagnostic marker for AIH [95,97]. In addition, interface hepatitis is considered as a marker of the AIH, albeit not a specific marker.…”

“…Subtype AIH-1 is characterized by the serological reactivity of ANA, SMA or both autoantibodies, and accounts for 80% of all AIH cases. The detection of anti-LKM-1 or anti-LC1 refers to subtype AIH-2, which occurs less often and mainly in pediatric patients [87,95]. Occasionally, however, there are AIH patients in which none of these autoantibodies can be detected.…”

“…In addition, interface hepatitis is considered as a marker of the AIH, albeit not a specific marker. The expansion of portal inflammation into the adjacent lobules, with damage to and the progressive loss of hepatocytes, is observed in up to 98% of AIH cases and is usually more prominent than in the interface of hepatitis from other causes [95].…”

Not only a small liver - The pathologist’s perspective in the pediatric liver transplant setting

“…Adult type conditions such as autoimmune hepatitis (AIH) 20 , 21 may also impact the pediatric population, while a pathologic condition that is rapidly increasing and concerning pediatric hepatologists is fatty liver disease 22 , 23 . Non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH) are well-known conditions affecting adults in the Western world 24 , although this “fatty liver pandemic” is now moving from the adult to the pediatric population.…”