Prevalence of IgG autoantibody against F-actin in patients suspected of having autoimmune or acute viral hepatitis

Autoantibody-negative autoimmune hepatitis

Autoimmune hepatitis has a variable clinical phenotype, and the absence of conventional autoantibodies does not preclude its diagnosis or need for treatment. The goals of this review are to describe the frequency and nature of autoantibody-negative autoimmune hepatitis, indicate its outcome after corticosteroid treatment, and increase awareness of the diagnosis in patients with unexplained acute and chronic hepatitis. The frequency of presumed autoantibody-negative autoimmune hepatitis in patients with acute and acute severe presentations is ≤7%, and its frequency in patients with chronic presentations is 1-34%. Patients with acute presentations can have normal serum γ-globulin levels, centrilobular zone 3 necrosis, and low pre-treatment international diagnostic scores. Liver tissue examination is essential for the diagnosis, and hepatic steatosis can be a co-morbid feature. The comprehensive international scoring system can support but never override the clinical diagnosis pre-treatment, and non-standard serological markers should be sought if the clinical diagnosis is uncertain or the diagnostic score is low. A 3-month treatment trial with corticosteroids should be considered in all patients, regardless of the serological findings, and improvements have occurred in 67-87% of cases. Autoantibody-negative autoimmune hepatitis may be associated with an autoantibody outside the conventional battery; it may have a signature autoantibody that is still undiscovered, or its characteristic autoantibodies may have been suppressed or have a delayed expression. The pathogenic mechanisms are presumed to be identical to those of classical disease. Autoantibody-negative autoimmune hepatitis is an infrequent but treatable disease that must be considered in unexplained acute and chronic hepatitis.

Autoantibodies as prognostic markers in autoimmune liver disease

Certain autoantibodies in autoimmune liver disease have prognostic implications that are under-utilized and under-developed. The goals of this review are to indicate progress in characterizing the autoantibodies with prognostic connotations and to indicate the feasibility and importance of discovering other markers. Prime source and review articles in English were selected by a Medline search through 2010. Antibodies to soluble liver antigen, actin, liver cytosol type 1, asialoglycoprotein receptor, chromatin, cyclic citrullinated peptide, and uridine glucuronosyltransferases have been associated with the occurrence, severity, and progression of autoimmune hepatitis, and antibodies to Sp100, gp210, and centromere have had similar implications in primary biliary cirrhosis. Antibodies to soluble liver antigen have shown the most promise in autoimmune hepatitis as they have been associated with severe histological changes, long durations of treatment, relapse after drug withdrawal, and high frequency of liver failure. Antibodies to the nuclear rim pore protein, gp210, have shown the most promise in primary biliary cirrhosis as they have been associated with severe interface hepatitis, lobular inflammation, and progression to liver failure. The major limitations of the autoantibodies have been their lack of standardized assays, low negative predictabilities, and fluctuating levels. Performance parameters will improve as critical pathogenic pathways, comprehensive testing batteries, and standardized assays through international exchange workshops are developed. Progress has been made in identifying the serological markers of prognosis in autoimmune liver disease, and they promise to reflect critical disease mechanisms and enhance patient management.

F-actin reactive smooth muscle antibody in subjects with normal liver function

AIMS

Smooth muscle antibody (SMA) with F-actin reactivity has been reported as a diagnostic marker of autoimmune hepatitis. We re-visited this relationship by randomly selecting SMA-positive sera to test for reactivity with F-actin by ELISA. We correlated such reactivity with liver function tests.

METHODS

Sera positive for SMA by indirect immunofluorescence were tested for reactivity by F-actin ELISA and the results correlated with liver function tests.

RESULTS

89 SMA-positive sera reacted with F-actin by ELISA. Of these, 35 (39%) had normal liver enzymes, while 54 (60%) had elevated liver enzymes. There was no difference between the groups with respect to age at presentation, female preponderance or presence of anti-nuclear antibody. In both groups, high titre SMA antibody predominantly with immunofluorescence staining of renal glomeruli and peritubular fibrils of renal tubules ('G/T' subset) correlated with makedly elevated F-actin values by ELISA. 'Actin cables' by immunofluorescence staining of Hep-2 cells were infrequently found in both groups.

CONCLUSIONS

This is the first report of SMA with F-actin reactivity in subjects with normal liver function.

Autoimmune hepatitis in the HIV-infected patient: a therapeutic dilemma

Autoimmune hepatitis (AIH) is a progressive, chronic hepatitis that has rarely been reported in HIV-infected individuals. Among patients who are candidates for hepatitis C virus (HCV) treatment, screening for AIH should be considered, because interferon has the potential to cause fulminant hepatic failure in the setting of immune-mediated injury. During a 4-year period, we identified four HIV-infected patients who were referred for evaluation of persistently elevated aminotransferases, two of whom were also infected with HCV. Serologic testing and the hepatic histologic appearance were consistent with AIH. Although each patient initiated treatment with corticosteroids and immunosuppressive agents, all four eventually developed life-threatening infectious or adverse metabolic effects that resulted in treatment discontinuation. Of note, one HIV/HCV co-infected patient was able to initiate HCV treatment with interferon after AIH remission was documented. While these cases illustrate that AIH can produce hepatic injury in virally infected individuals, we recommend that treatment for AIH in HIV-infected patients should be individualized after careful consideration of the potential risks and likely benefits.

Autoimmune liver disease

PURPOSE OF REVIEW

To review studies that improve the diagnosis and treatment of autoimmune hepatitis and extend understanding of its pathogenic mechanisms.

RECENT FINDINGS

Black patients have more advanced disease and poorer outcomes than white patients. Genome-wide DNA microsatellite techniques have identified multiple regions that may confer susceptibility or resistance to the disease. Preferential inactivation of one parentally-derived X chromosome may favor autoreactivity in women. Acute and chronic hepatitis of undetermined cause can respond to corticosteroid therapy and represent autoantibody-negative autoimmune hepatitis. Outcomes can be improved by continuing therapies until resolution of all features and by early identification of problematic patients with the Model for End Stage Liver Disease. Serum levels of B-cell activating factor correlate with laboratory indices of liver injury. Tacrolimus and mycophenolate mofetil are promising therapies for problematic patients, and the antigenic targets of atypical antibodies to liver/kidney microsome may lead to diagnostic tests for de-novo autoimmune hepatitis after liver transplantation.

SUMMARY

Ethnic background and genetic predisposition affect the occurrence and outcome of autoimmune hepatitis. Susceptibility and resistance factors across the human genome underscore the genetic complexity of the disease. Outcomes can be improved by better use of current regimens and further evaluation of action-specific immunosuppressive agents.