Eva Hitchman

Correlation of initial autoantibody profile and clinical outcome in primary biliary cirrhosis

Although there have been significant advances in understanding the clinical and biochemical features of primary biliary cirrhosis (PBC), there is still a paucity of data on the usefulness of biomarkers as prognostic indicators. This is particularly important at the time of initial diagnosis. Indeed, the widespread use of antimitochondrial antibody testing has led to an earlier diagnosis of asymptomatic PBC and it is difficult to predict which patients will experience a benign versus a rapidly progressive course. To address this issue, we examined a unique population of 127 newly diagnosed patients with PBC during a 15‐year period of observation that began in January 1990. Sera from these patients were analyzed for antimitochondrial, antinuclear, and anti–smooth muscle antibodies, and immunoblotting was performed for nuclear pore complex (NPC). The patients were then followed up longitudinally using biochemical liver function tests. No patient was under any medical therapy for PBC at the time of the initial sera collection. Data were analyzed based not only on the clinical features, but also the Mayo score and specific outcome measures, including time to death, need for liver transplantation, and complication free survival. Among patients with early disease, bilirubin increased to >2 mg/dL in the anti‐NPC(+) patients (26% vs. 5%, P = .019). Anti‐NPC antibodies remained stable or slightly increased over the period of observation. In conclusion, anti‐NPC identifies patients likely to experience an unfavorable clinical course and more rapid disease progression. (HEPATOLOGY 2006;43:1135–1144.)

Autoantibodies against nuclear pore complexes are associated with more active and severe liver disease in primary biliary cirrhosis

BACKGROUND/AIMS Antibodies against nuclear pore complexes (NPCs) have been detected in primary biliary cirrhosis (PBC), but their clinical relevance is still unsettled. METHODS We tested sera from 171 consecutive PBC patients and 230 control subjects (149 with autoimmune or viral liver diseases, 28 with systemic lupus erythematosus, and 53 healthy) by immunoblotting for antibodies against purified human NPCs. RESULTS Antibodies to NPCs were detected in 27% of the patients with PBC, were highly specific (97%), and were not associated with antimitochondrial antibodies. Their prevalence was higher in symptomatic patients (36 vs. 16%, P < 0.01) and was associated (P < 0.001) with more severe disease, as assessed by the presence of cirrhosis or its complications (13% prevalence in patients without cirrhosis, 31% in uncomplicated, and 54% in complicated cirrhosis), or by the application of the Mayo prognostic model (12% in the lowest, 21% in the median, 47% in the highest score tertile). Positive patients had higher levels of serum bilirubin (2.2 +/- 3.7 vs. 1.0 +/- 1.1 mg/dl, P < 0.01) and more marked inflammatory infiltrates on liver biopsy (P < 0.05). CONCLUSIONS Autoantibodies to NPCs are more prevalent in PBC patients than in controls and are strongly associated with more active and severe disease.

Members of the glutathione S-transferase gene family are antigens in autoimmune hepatitis.

BACKGROUND & AIMS Autoimmmune hepatitis (AIH), a chronic liver disorder, can be classified into two subtypes on the basis of the specificities of circulating autoantibodies. Type I AIH is defined by antibodies to nuclear and/or smooth muscle antigens (SMA), and type II is characterized by antibodies to cytochrome P450IID6. There is an additional type of AIH characterized by antibodies to a cytosolic soluble liver antigen (SLA), which can occur alone or in combination with antinuclear antibodies and SMA. The aim of this study was to identify the reactive antigen in SLA, a heterogenous cytosolic fraction consisting of at least 100 extremely soluble proteins. METHODS Sera from 31 patients with AIH reacting with SLA and from 30 disease controls were tested. The immunoreactive antigens were determined using immunoprecipitation and immunoblotting after one- and two-dimensional polyacrylamide gel electrophoresis. The antigens were identified by microsequencing of the corresponding protein spots. RESULTS Twenty-five of 31 anti-SLA-positive sera (80, 7%) reacted with a set of proteins ranging from 25 to 27 kilodaltons that were identified as three subunits of glutathione S-transferases: Ya, Yb1, and Yc. CONCLUSIONS Glutathione S-transferase subunit proteins represent the major autoantigen in anti-SLA-positive AIH. This new finding permits the establishment of standardized immunoassays for routine diagnosis.

Antibodies to nuclear lamins in autoimmune liver disease

Antibodies to nuclear lamins were detected in sera of patients with autoimmune liver disease. In indirect immunofluorescence tests, these sera revealed staining of the nuclear periphery. Using isolated nuclei, nuclear matrices, nuclear lamina-pore complexes, and chromatographically purified lamins as antigen source, the nuclear lamins A, B, and C were identified as reactive antigens in immunoblotting experiments. The lamins were also identified by 2-D gel electrophoresis. Antibodies to nuclear lamins occurred in 12 of 16 cases of active lupoid hepatitis, but not in 35 patients with the disease in remission. However, only 3 of 37 sera of patients with primary biliary cirrhosis contained anti-lamin antibodies. Autoimmune liver disease sera reacted preferentially with lamins A/C and less frequently with lamin B or lamins A/B/C.

Anti-gp210 antibodies in sera of patients with primary biliary cirrhosis. Identification of a 64 kD fragment of gp210 as a major epitope.

Patients with primary biliary cirrhosis (PBC) frequently produce autoantibodies against gp210, an integral glycoprotein of the nuclear pores. this protein consists of three main domains: a large glycosylated lumenal domain, a single hydrophobic transmembrane segment and a short cytoplasmic tail. It has been previously shown that autoantibodies from PBC patients exclusively react with the cytoplasmic tail when recombinant rat gp210 expressed in Escherichia coli was used as antigen. Using human gp210 isolated from HeLa cells we found the lumenal domain as the major target. The aim of this study was to further characterize the dominant autoepitopes of gp210. Sera from 88 patients with autoimmune liver disease and 20 controls were used. Gp210 protein was digested with papain or endoglycosidase H and then subjected to immunoblotting. Autoantibodies against gp210 were detected in 12 of 43 (28%) PBC patients, but in none of the autoimmune hepatitis and control sera. Four of 12 (33%) anti-gp210 positive sera reacted with a fragment consisting of the cytoplasmic tail and 8 (66%) sera targeted an epitope located within the large lumenal domain. Furthermore, our data show that antigenic determinant is restricted to the 64 kD glycosylated amino-terminal fragment and that carbohydrate residues are an essential part of this novel epitope. We suggest that antigens possessing both epitopes namely; the glycosylated lumenal domain and the cytoplasmic tail should be used for screening tests in order to detect all sera with anti-gp210 specificity.

Antibodies to nuclear Lamin proteins in liver Disease

Sera of patients with autoimmune liver disease contained antibodies reactive with nuclear lamins. These antigens were identified in immunoblotting experiments, using isolated nuclei, nuclear matrices, nuclear lamina-pore complexes and purified lamins as antigen source. The lamins were, furthermore, characterized by 2-dimensional gel electrophoresis. Antibodies to nuclear lamins were found in 75 per cent of the active lupoid hepatitis cases, but not in patients with inactive disease. Anti-lamin antibodies were detected in 8 per cent of primary biliary cirrhosis sera. The autoimmune liver disease sera recognized predominantly the nuclear lamins A/C, and less frequently the lamins A/B/C or lamin B.

Nuclear ADP-Ribosyltransferase as Target Antigen in Chronic Graft-Versus-Host Disease

Chronic graft-versus-host disease (c-GVHD), one of the major clinical complication of human allogeneic bone marrow transplantation has similarities with autoimmune diseases such as systemic lupus erythematosus or scleroderma (Ferrara and Deeg, 1991;Shulman and Sullivan, 1988). Screening by immunofluorescence microscopy suggested the presence of antinuclear autoantibodies in the sera of allogeneic bone marrow graft recipients (Shulman et al., 1980;Kier et al., 1990).