The many faces and pathologic diagnostic challenges of autoimmune hepatitis

Autoimmune hepatitis (AIH) is an immune-mediated chronic inflammatory liver disease, characterized by hypergammaglobulinemia, the presence of specific autoantibodies, and typical abnormalities in liver histology. Prompt diagnosis and initiation of immunosuppressive treatment are necessary for both chronic and acute onset AIH to prevent progression to end-stage liver disease or fatal liver failure. However, the diagnosis of AIH is challenging mainly because of its heterogeneous clinical, serological and pathological features. Although portal lymphoplasmacytosis and interface hepatitis are the most typical histological features of AIH, many other histological features can be observed in AIH, including emperipolesis, hepatocyte rosettes, and Kupffer cell hyaline globules. Recent studies have questioned emperipolesis and hepatocyte rosette formation as typical features of AIH, and atypical clinical and histological presentations have also been recognized. This led an international working group to propose the modified AIH diagnostic criteria. However, it is well recognized that there are no pathognomonic characteristics that can be used to diagnose AIH and careful clinicopathological correlation is required to arrive at the correct diagnosis. The aim of this review is to summarize the histological features of AIH, its varied histopathologic spectrum, recent updates and major differential diagnoses in routine clinical practice.

Clinical characteristics and treatment outcomes of acute severe autoimmune hepatitis

Background and aim

Acute severe autoimmune hepatitis (AS-AIH) is a rare cause of acute liver failure (ALF), which is often neglected and delayed in treatment. The purpose of this study was to analyze the clinical characteristics and therapeutic effects of AS-AIH.

Methods

Retrospective analysis was performed. AIH was diagnosed according to the International Autoimmune Hepatitis Group (IAIHG) criteria revised in 1999. AS-AIH was defined as an acute presentation (onset of symptoms to presentation of ≤ 26 weeks) and INR of ≥ 1.5, and no histologic evidence of cirrhosis.

Results

Twelve patients were diagnosed as AS-AIH. At baseline, median immunoglobulin G was 28.35 g/L (range, 11.4–49.2). Ten (83.3%) patients were antinuclear antibodies and/or anti-smooth muscle antibodies positive. The prominent histologic characteristics were lobular necrosis/inflammation (91.7%) and plasma cell infiltration (100%). All patients received corticosteroid therapy. Death occurred in 2 (16.7%) patients within 30 days resulted from ALF. The average interval between the onset of symptoms and initiation of corticosteroid therapy in deceased patients was 65 days, compared with 19 days for survivors.

Conclusions

AS-AIH is an uncommon disease with poor outcomes. Patients with acute severe hepatitis of unknown cause should be minded the possibility of AS-AIH and corticosteroids should be considered as soon as possible.

Liver injury after methylprednisolone pulse therapy in multiple sclerosis is usually due to idiosyncratic drug-induced toxicity rather than autoimmune hepatitis

BACKGROUND

In patients with multiple sclerosis (MS), development of hepatic injury has been sporadically reported after methylprednisolone (MP) pulse therapy. Some studies suggest autoimmune hepatitis, while other studies reported direct hepatotoxicity as a cause for hepatic injury. Here, we studied the pathological mechanism of such liver injury in patients with MS.

METHODS

From 2005 to 2016, eight patients with MS developed liver injury after MP pulse therapy. Their average age was 38 years (range: 28-49 years, all female). Autoimmune antibodies were measured and a liver biopsy was performed in seven patients.

RESULTS

Liver injury developed within two weeks in two patients and later (30-90 days after MP) in six patients. No hepatitis-related autoantibody or hepatitis virus were found. All cases were classified as hepatocellular injury and none as cholestatic or mixed. A liver biopsy in five cases revealed centrilobular necrosis with lobular infiltrates of inflammatory cells, suggesting drug-induced acute hepatitis. The biopsy findings in another case suggested a residual stage of acute hepatitis. Only one patient showed portal expansion with periportal fibrosis, suggesting autoimmune hepatitis. All patients recovered spontaneously or with only hepatoprotective drugs, although one patient with possible autoimmune hepatitis recovered slowly.

CONCLUSION

Liver injury develops usually later than two weeks after MP treatment. The prognosis is good in most cases and rarely autoimmune hepatitis may be involved.

Centrilobular necrosis in acute presentation of Japanese patients with type 1 autoimmune hepatitis

AIM

To compare clinicopathological features of acute presentation of type 1 autoimmune hepatitis (AIH) with or without centrilobular necrosis (CN).

METHODS

Our study comprised 41 patients with biopsy-proven acute presentation (acute exacerbation phase 36, acute hepatitis phase 5) of type 1 AIH at our hospital from 1975 to 2009. Elevated serum alanine aminotransferase (ALT) (> 5x upper limit of normal) identified acute presentation of the disease. We compared clinicopathological features of these AIH patients with or without CN. The data used for analysis included patient background (age, sex, type of disease, presence of complications with other autoimmune diseases, human leukocyte antigen, and International Autoimmune Hepatitis Group score), clinical parameters at presentation (ALT, alkaline phosphatase, IgG, anti-nuclear antibodies, and anti-smooth muscle antibodies), histology and therapy.

RESULTS

CN was found in 13 (31.7%) patients with acute presentation (acute exacerbation phase 10, acute hepatitis phase 3) of AIH. Serum IgG levels of patients with CN were significantly lower than those of patients without CN (mean: 2307 mg/dL vs 3126 mg/dL, P < 0.05), while antinuclear antibody-negative rates were significantly higher (30.7% vs 3.5%, P < 0.05). However, other clinical features were similar between the two groups. The frequency of advanced fibrosis in patients with CN was significantly lower than in patients without CN (F0-2: 84.6% vs 35.7%, F3-4: 15.4% vs 64.3%, P < 0.05). Other histological features were similar between the two groups. Although there was no significant difference between groups when evaluated using the revised original score (12 vs 14), the simplified AIH score of patients with CN was significantly lower (6 vs 7, P < 0.05). Frequency of DR4 was similar between patients with and without CN.

CONCLUSION

CN is observed in both Japanese patients with acute hepatitis phase and acute exacerbation phase of type 1 AIH, although AIH with CN often shows clinical features of the genuine acute form.