Anti-tRNP(ser)sec/SLA/LP autoantibodies. Comparative study using in-house ELISA with a recombinant 48.8 kDa protein, immunoblot, and analysis of immunoprecipitated RNAs

Permanent immunosuppression in SLA/LP-positive autoimmune hepatitis is required although overall response and survival are similar

BACKGROUND AND AIMS

Antibodies against soluble liver antigen/liver pancreas (anti-SLA/LP) are highly specific for autoimmune hepatitis (AIH) and have been linked with a more severe clinical course of the disease, frequent relapses after treatment withdrawal and worse outcome. To address definitely the clinical significance of anti-SLA/LP, we investigated a large number of anti-SLA/LP-positive and -negative patients followed in three referral centres.

METHODS

Prospectively collected data from 89 anti-SLA/LP-positive AIH patients (29 from Hamburg-Germany, 20 from Bologna-Italy and 40 from Larissa-Greece) were analysed retrospectively. Age- and sex-matched anti-SLA/LP-negative patients served as disease controls (n = 230; 1:2.5 ratio).

RESULTS

In respect to baseline characteristics, anti-SLA/LP-positive patients were more frequently asymptomatic compared to anti-SLA/LP-negative (P < .05). However, anti-SLA/LP-positive patients did not differ from anti-SLA/LP-negative in terms of the overall response to treatment, disease progression and survival even though, they were less likely to achieve corticosteroid withdrawal (P < .05), needed longer treatment duration to achieve first complete response (P < .001) and relapsed more frequently after treatment withdrawal compared to anti-SLA/LP-negative patients (P = <.001).

CONCLUSIONS

We showed that anti-SLA/LP antibodies do not characterize a group of AIH patients with distinct features and cannot identify patients with a more severe form of the disease or worse survival. Most importantly, however, anti-SLA/LP-positive patients appear to require lifelong immunosuppression as they are less likely to achieve the cessation of corticosteroids and present higher relapse rates after treatment withdrawal. Therefore, close long-term monitoring should be advised in all anti-SLA/LP-positive patients after withdrawal of immunosuppressive treatment.

Autoimmune Hepatitis in the Elderly: Diagnosis and Pharmacologic Management

Autoimmune hepatitis (AIH) may present as acute or chronic hepatitis in the elderly. Advanced hepatic fibrosis and cirrhosis are common on first presentation in this population. In this review, we discuss the presentation, approach to diagnosis and management of AIH in the elderly. As polypharmacy is common in the elderly, careful medication use history is essential for detecting drug-induced AIH-like hepatitis. Steroid-sparing or minimizing therapeutic regimens are preferred to treat AIH in the elderly. For the purpose of induction, budesonide or lower dose prednisone in combination with azathioprine (AZA) regimens are preferred over high-dose prednisone monotherapy due to the higher risk of side effects of the later in the elderly. The goal of maintenance therapy should be to achieve full biochemical and histologic remission. Bone density monitoring and interventions to prevent steroid-related bone disease should be implemented throughout the course of the disease. Liver transplantation should be considered in the elderly patient with liver failure or early hepatocellular carcinoma if there are no significant comorbidities or compromise in functional status.

Anti-SLA/LP alone or in combination with anti-Ro52 and fine specificity of anti-Ro52 antibodies in patients with autoimmune hepatitis

BACKGROUND & AIMS

Antibodies (Abs) to soluble liver antigen/liver pancreas (anti-SLA/LP) are considered markers of worse prognosis and outcome in patients with autoimmune hepatitis (AIH) although this assumption has recently been attributed to their frequent co-expression with Abs against Ro52 (anti-Ro52). To assess the clinical significance of anti-SLA/LP Abs alone or in combination with anti-Ro52 in AIH patients and determine the immunodominant Ro52 epitopes according to the anti-SLA/LP status.

METHODS

Twenty-three anti-SLA/LP-positive and 106 anti-SLA/LP-negative AIH patients were included. Anti-SLA/LP were determined by ELISA using recombinant antigen, and confirmed by immunoblot using cytosolic rat liver fraction or HuH-7 extract. Anti-Ro52 Abs were determined by ELISA using recombinant antigen. Epitope mapping was assessed by ELISA using overlapping peptides covering the whole Ro52 protein in 26 AIH patients and 12 patients with Sjögren's syndrome.

RESULTS

Anti-SLA/LP positivity was not associated with the clinical, laboratory or histological characteristics of AIH patients. Treatment response, corticosteroid withdrawal, relapse after stopping treatment and outcome, were not associated with the presence of anti-SLA/LP, anti-Ro52 or double reactivity. Moreover, Ro52 epitope mapping revealed new epitopes unique for AIH and independent from anti-SLA/LP positivity.

CONCLUSIONS

Neither anti-SLA/LP nor anti-Ro52 Abs or their combination could specify a distinct group of AIH patients in terms of clinical characteristics, treatment response and outcome. Further studies are needed to clarify whether the newly discovered immunodominant epitopes of Ro52 antigen which were associated specifically with AIH have any clinical or pathogenetic significance in AIH.

Development of a recombinant cell-based indirect immunofluorescence assay for the determination of autoantibodies against soluble liver antigen in autoimmune hepatitis

Autoantibodies against soluble liver antigen (SLA) are specific markers for autoimmune hepatitis (AIH) type 1. In contrast to the determination of other AIH-associated autoantibodies by indirect immunofluorescence assay (IFA), detection of anti-SLA relied up to now on ELISA or immunoblot based on bacterially expressed recombinant protein. In order to develop a complementary IFA substrate, SLA isoform 1 was recombinantly produced in the human cell line HEK293 and controlled by a rabbit hyperimmune serum against SLA. The recombinant cells were used in IFA (RC-IFA) to analyze sera from 20 AIH patients with anti-SLA positivity predetermined by ELISA together with 80 controls (20 anti-SLA negative AIH, 15 primary biliary cirrhosis, 15 HCV, and 30 healthy blood donors). Using RC-IFA, anti-SLA was detected in all ELISA positive AIH sera but in none of the controls. Furthermore, a cytosolic fraction of HEK293 containing SLA was able to neutralize the autoantibodies in all positive sera in a dose-dependent manner. HEK293 cells expressing SLA are a valid substrate for the serodiagnosis of AIH relevant autoantibodies by IFA. In concert with cryosections of primate liver, rat kidney, rat liver, rat stomach, and HEp-2 cells, they enable the parallel determination of all autoantibodies associated with autoimmune liver diseases.

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.

The role of autoantibodies as diagnostic markers of autoimmune hepatitis

Autoantibody testing is the first step towards the diagnosis of autoimmune hepatitis, and it is essential in the evaluation of acute and chronic hepatitis of undetermined cause and allograft dysfunction following liver transplantation. A standard diagnostic repertoire has been promulgated, and other autoantibodies are emerging that may have prognostic value. Supplemental autoantibodies may prove useful in assessing patients who lack the standard markers or who are distinctive among those with conventional markers. Serologic testing will improve as assays are standardized by serum exchange workshops, core diagnostic batteries are codified and promulgated, and markers emerge that are tightly associated with pathogenic mechanisms, and closely reflect disease activity and outcome.

Significance of antibodies to soluble liver antigen/liver pancreas: a large French study

BACKGROUND

Antibodies to soluble liver antigen (SLA)/liver pancreas (LP) are generally considered as highly specific diagnostic markers of type 1 auto-immune hepatitis (AIH-1), and are particularly useful in patients without conventional antibodies. However, the presence of anti-SLA/LP in type 2 auto-immune hepatitis (AIH-2), primary sclerosing cholangitis (PSC) and hepatitis C has recently been reported. The aim was thus to describe the characteristics of anti-SLA/LP-positive patients in the largest series reported to date.

METHODS

Sera were selected from the period between 1998 and 2005, based on the presence of antibodies to SLA/LP detected by two methods. The clinical status of patients was determined from their medical records.

RESULTS

Eighty-one anti-SLA/LP-positive patients with available clinical data were included: 89% (72/81) had a diagnosis of AIH-1, including 10 (12%) associated with cholestatic diseases (primary biliary cirrhosis in seven cases and PSC in three cases). Six patients (7%) suffered from another liver disease: hepatitis C (n=3) and drug-induced hepatitis (n=3). No specific diagnosis was made in three patients.

CONCLUSIONS

Antibodies to SLA/LP are of a major diagnostic value for AIH-1, including paediatric forms and overlap syndromes with cholestatic diseases, but are not found in association with anti-liver/kidney/microsome type 1 or antibodies to liver cytosol type 1. They are rarely present in other liver diseases such as hepatitis C and drug-induced hepatitis.

Autoimmune liver disease

PURPOSE OF REVIEW

To review studies that improve the diagnosis and treatment of autoimmune hepatitis and presage new drug and molecular site-specific interventions.

RECENT FINDINGS

Autoimmune hepatitis can present as acute or chronic hepatitis and as allograft dysfunction after liver transplantation. Elderly patients have an indolent but aggressive disease that responds well to corticosteroid therapy, and human leukocyte antigen DR4 characterizes this population. Geographic and ethnic factors influence clinical phenotype and behavior, and defects in T-regulatory cells may enhance cell-mediated cytotoxicity. Treatment response is the best index of prognosis, and normalization of serum aminotransferase abnormalities prevents disease progression. Mycophenolate mofetil, budesonide, rapamycin, and 6-thioguanine have been effective in small clinical experiences. De-novo autoimmune hepatitis can occur in adults and children after liver transplantation, and rapamycin may be an effective treatment.

SUMMARY

Autoimmune hepatitis has a global distribution and diverse clinical manifestations. Phenotypes are affected by regional and ethnic factors which may provide clues to the etiologic agents. Defects in counter-regulatory functions enhance cell-mediated cytotoxicity, and interventions that promise site-specific actions affecting immunocyte differentiation and proliferation are now feasible. Autoimmune hepatitis must be considered in all patients with acute and chronic hepatitis and in all cases of allograft dysfunction after liver transplantation.

Autoantibodies in autoimmune liver disease

Autoantibodies indicate an immune reactive state, but in liver disease they lack pathogenicity and disease specificity. Antinuclear antibodies, smooth muscle antibodies, antibodies to liver/kidney microsome type 1, antimitochondrial antibodies, and perinuclear antineutrophil cytoplasmic antibodies constitute the standard serological repertoire that should be assessed in all liver diseases of undetermined cause. Antibodies to soluble liver antigen/liver pancreas, asialoglycoprotein receptor, actin, liver cytosol type 1, nuclear antigens specific to primary biliary cirrhosis, and pore complex antigens constitute an investigational repertoire that promises to have prognostic and diagnostic value. These autoantibodies may emerge as predictors of treatment response and outcome. Antibodies to histones, doubled-stranded DNA, chromatin, and lactoferrin constitute a supplemental repertoire, and they support the immune nature of the liver disease. Final diagnoses and treatment strategies do not depend solely on serological markers. Autoantibodies are floating variables, and their behavior does not correlate closely with disease activity. There are no minimum levels of significant seropositivity, especially in children. Over-interpretation is the major pitfall in the clinical application of the serological results. New autoantibodies will emerge as the search for target antigens and key pathogenic pathways continues.