The role of macrophage migration inhibitory factor in autoimmune liver disease.

UNLABELLED: The role of the cytokine, macrophage migration inhibitory factor (MIF), and its receptor, CD74, was assessed in autoimmune hepatitis (AIH) and primary biliary cirrhosis (PBC). Two MIF promoter polymorphisms, a functional -794 CATT5-8 microsatellite repeat (rs5844572) and a -173 G/C single-nucleotide polymorphism (rs755622), were analyzed in DNA samples from over 500 patients with AIH, PBC, and controls. We found a higher frequency of the proinflammatory and high-expression -794 CATT7 allele in AIH, compared to PBC, whereas lower frequency was found in PBC, compared to both AIH and healthy controls. MIF and soluble MIF receptor (CD74) were measured by enzyme-linked immunosorbent assay in 165 serum samples of AIH, PBC, and controls. Circulating serum and hepatic MIF expression was elevated in patients with AIH and PBC versus healthy controls. We also identified a truncated circulating form of the MIF receptor, CD74, that is released from hepatic stellate cells and that binds MIF, neutralizing its signal transduction activity. Significantly higher levels of CD74 were found in patients with PBC versus AIH and controls. CONCLUSIONS: These data suggest a distinct genetic and immunopathogenic basis for AIH and PBC at the MIF locus. Circulating MIF and MIF receptor profiles distinguish PBC from the more inflammatory phenotype of AIH and may play a role in pathogenesis and as biomarkers of these diseases.

Antimitochondrial antibody heterogeneity and the xenobiotic etiology of primary biliary cirrhosis.

UNLABELLED: Antimitochondrial antibodies (AMAs) directed against the lipoyl domain of the E2 subunit of pyruvate dehydrogenase (PDC-E2) are detected in 95% of patients with primary biliary cirrhosis (PBC) and are present before the onset of clinical disease. The recent demonstration that AMAs recognize xenobiotic modified PDC-E2 with higher titers than native PDC-E2 raises the possibility that the earliest events involved in loss of tolerance are related to xenobiotic modification. We hypothesized that reactivity to such xenobiotics would be predominantly immunoglobulin M (IgM) and using sera from a large cohort of PBC patients and controls (n = 516), we examined in detail sera reactivity against either 6,8-bis(acetylthio) octanoic acid (SAc)-conjugated bovine serum albumin (BSA), recombinant PDC-E2 (rPDC-E2) or BSA alone. Further, we also defined the relative specificity to the SAc moiety using inhibition enzyme-linked immunosorbent assay (ELISA); SAc conjugate and rPDC-E2-specific affinity-purified antibodies were also examined for antigen specificity, isotype, and crossreactivity. Reactivity to SAc conjugates is predominantly IgM; such reactivity reflects a footprint of previous xenobiotic exposure. Indeed, this observation is supported by both direct binding, crossreactivity, and inhibition studies. In both early and late-stage PBC, the predominant Ig isotype to SAc is IgM, with titers higher with advanced stage disease. We also note that there was a higher level of IgM reactivity to SAc than to rPDC-E2 in early-stage versus late-stage PBC. Interestingly, this finding is particularly significant in light of the structural similarity between SAc and the reduced form of lipoic acid, a step which is similar to the normal physiological oxidation of lipoic acid. CONCLUSION: Specific modifications of the disulfide bond within the lipoic-acid-conjugated PDC-E2 moiety, i.e., by an electrophilic agent renders PDC-E2 immunogenic in a genetically susceptible host.

Colchicine or methotrexate, with ursodiol, are effective after 20 years in a subset of patients with primary biliary cirrhosis.

BACKGROUND & AIMS: The combination of ursodeoxycholic acid (UDCA), colchicine, and methotrexate (MTX) is effective therapy for a subset of patients with primary biliary cirrhosis (PBC) who do not respond to UDCA. However, the durability of the response is unclear. We investigated whether the response to combination therapy was durable. METHODS: We followed, for 10 additional years (range 9-13 years), 29 patients with PBC who had been treated with the combination of UDCA and MTX or UDCA and colchicine in a randomized controlled trial that began in 1988 and lasted 10 years. RESULTS: Of the 11 patients given MTX plus UDCA, 9 were still alive and well, whereas 2 died from causes unrelated to liver disease at the ages of 79 and 70. Of the 18 patients given the combination of colchicine and UDCA, 12 were alive and well 20 years after the trial ended. Three had progressive liver disease; 2 of these had liver transplantation and 1 died of pneumonia. Three died of unrelated causes at the ages of 73, 76, and 76 years, respectively. CONCLUSIONS: Treatment with the combination of UDCA and MTX or UDCA and colchicine led to sustained clinical remission in a subset of patients with PBC. The response to the combination of UDCA and MTX appeared to be more durable than to UDCA and colchicine.

Prevalence of primary biliary cirrhosis-autoimmune hepatitis overlap syndrome.

BACKGROUND & AIMS: The prevalence of and the most appropriate way to diagnose the primary biliary cirrhosis (PBC)-chronic autoimmune hepatitis (AIH) overlap syndrome are uncertain. We investigated the prevalence of PBC and AIH and their level of overlap at a tertiary referral center, along with clinical, biochemical, and serologic characteristics. METHODS: We reviewed data from all patients with PBC (n = 609) and/or AIH (n = 15) examined at the Tufts Medical Center (Boston, MA) from January 1, 2000, to June 20, 2006. PBC was diagnosed based on 2 of the following 3 results: 6 months of positive results in tests for cholestatic liver enzymes, a positive result in a test for antimitochondrial antibodies, or a liver biopsy that indicated PBC. AIH was defined as an alanine aminotransferase level of 200 U/L or greater (≥ 5-fold above normal), a liver biopsy that indicated severe interface hepatitis, and levels of immunoglobulin G 2-fold or greater than that of normal. RESULTS: Only 6 patients with PBC (1%) met the Paris criteria for the overlap syndrome. If we included 9 patients with PBC who did not meet the Paris criteria, but had results from liver enzyme tests and liver biopsy analyses that indicated improvement after treatment with prednisone, the prevalence was 15 (2.8%). This is at the low end of previously reported prevalence values for overlap of PBC and AIH (2%-20%). CONCLUSIONS: The prevalence of the PBC-AIH overlap syndrome varies among medical centers. We propose that if the definition of PBC-AIH overlap syndrome be modified to include patients with unequivocal responses to prednisone despite not meeting the Paris criteria, this would improve treatment of patients.

Identification of HLA-A2-restricted CD8(+) cytotoxic T cell responses in primary biliary cirrhosis: T cell activation is augmented by immune complexes cross-presented by dendritic cells.

Primary biliary cirrhosis (PBC) is characterized by an intense biliary inflammatory CD4(+) and CD8(+) T cell response. Very limited information on autoantigen-specific cytotoxic T lymphocyte (CTL) responses is available compared with autoreactive CD4(+) T cell responses. Using peripheral blood mononuclear cells (PBMCs) from PBC, we identified an HLA-A2-restricted CTL epitope of the E2 component of pyruvate dehydrogenase (PDC-E2), the immunodominant mitochondrial autoantigen. This peptide, amino acids 159-167 of PDC-E2, induces specific MHC class I-restricted CD8(+) CTL lines from 10/12 HLA-A2(+) PBC patients, but not controls, after in vitro stimulation with antigen-pulsed dendritic cells (DCs). PDC-E2-specific CTLs could also be generated by pulsing DCs with full-length recombinant PDC-E2 protein. Furthermore, using soluble PDC-E2 complexed with either PDC-E2-specific human monoclonal antibody or affinity-purified autoantibodies against PDC-E2, the generation of PDC-E2-specific CTLs, occurred at 100-fold and 10-fold less concentration, respectively, compared with soluble antigen alone. Collectively, these data demonstrate that autoantibody, helper, and CTL epitopes all contain a shared peptide sequence. The finding that autoantigen-immune complexes can not only cross-present but also that presentation of the autoantigen is of a higher relative efficiency, for the first time defines a unique role for autoantibodies in the pathogenesis of an autoimmune disease.

Statins in primary biliary cirrhosis: are they safe?

BACKGROUND AND AIM: Although cholesterol levels are elevated in patients with primary biliary cirrhosis (PBC), most PBC patients are not at increased risk of dying from atherosclerotic heart disease. There is, however, a subgroup, approximately 10%, who have additional disorders of lipid metabolism. They might benefit from a cholesterol-lowering agent. However, there is concern about using statins in patients with pre-existing liver disease. We therefore reviewed our experience with statins in a large cohort of PBC patients who were seen at Tufts Medical Center during the past decade. METHODS: From January 1, 1996, until June 30, 2006, 603 patients with PBC were seen by one of us (M.M.K.). Fifty-eight were on statins and five were on ezetimibe. The mean duration of usage was 41 months (range 3-125 months). Alanine aminotransferase (ALT) levels were measured at 3-month intervals. RESULTS: Statins were well tolerated. No patient complained of muscle pain or weakness. There was no increase in ALT levels. ALT levels were slightly elevated at the time that statins were begun (41.7 +/- 25.1 U/l), and were normal at the last time these patients were seen (39.0 +/- 21.0 U/l) (P

Methotrexate in patients with primary biliary cirrhosis who respond incompletely to treatment with ursodeoxycholic acid.

BACKGROUND: Approximately 35% of PBC patients have progressive disease despite treatment with UDCA. AIMS: We offered treatment with methotrexate and colchicine to PBC patients who had not responded fully to UDCA, after at least 1 year of treatment. METHODS: A total of 91 PBC patients failed to respond adequately to UDCA, defined as patients whose liver biopsies showed persistent interface hepatitis and whose serum alkaline phosphatase levels remained more than 50% above normal after at least 12 months on UDCA. We added colchicine (0.6 mg orally twice daily) for 6 months. If there was no decrease in alkaline phosphatase, methotrexate (0.25 mg/kg lean body weight orally per week) was added. Liver biopsies were performed at least three times: at diagnosis, after a patient had been on UDCA for at least 1 year (mean 3.4 years), and after a patient had been on methotrexate for at least 6 months (mean 2.2 years). A fourth liver biopsy was performed in 51 patients after they had been on methotrexate for at least another year (mean 3.5 years). RESULTS: From the time that methotrexate was begun until the final visit, there were significant decreases in the mean levels of alkaline phosphatase, 323 to 151, ALT, 73 to 39, fibrosis, 2.5 to 2.0, and inflammation scores, 2.0 to 1.0, (p < 0.0001 for all). Based on pre-specified definitions, 73 patients (80%) responded to methotrexate while 18 (20%) did not. CONCLUSIONS: In 91 PBC patients who responded incompletely to UDCA, colchicine and methotrexate significantly improved liver enzyme tests and liver histology.

Risk of non-melanoma skin cancer in autoimmune hepatitis.

BACKGROUND: Most patients with autoimmune hepatitis (AIH) require long-term immunosuppressive therapy (IS). While it is well established that solid organ transplant recipients have a high risk of developing non-melanoma skin cancer (NMSC) as a result of immunosuppression, little is known about the risk of NMSC associated with IS in patients with AIH. OBJECTIVES: The aim of this study is to determine the incidence and risk factors for NMSC in patients on IS for AIH. METHODS: We reviewed the medical records of all patients with AIH seen at a tertiary care medical center between 1998 and 2008. We compared the incidence of NMSC to an age- and sex-matched control population and analyzed risk factors for NMSC. RESULTS: A total of forty-five patients with AIH were identified. Twenty NMSC lesions were found in eight patients. Compared to the age and sex-matched general population, the risk of SCC and BCC were increased as quantified by elevated standardized incidence ratios (28.5 and 5.0, respectively). Patients who developed NMSC were on average 24 years older (78.4 vs. 54.2 years old, p < 0.0001) and had AIH diagnosed at a more advanced age (66.0 vs. 45.4 years old, p = 0.0003). CONCLUSION: The risk of NMSC is significantly increased in patients with AIH on immunosuppression. Independent risk factors include current age and age at diagnosis of AIH.

Modafinil in the treatment of debilitating fatigue in primary biliary cirrhosis: a clinical experience.

Modafinil may be a potentially effective treatment for primary biliary cirrhosis (PBC)-related fatigue. About 42 patients were given a 3-day trial of 100-200 mg modafinil. Response was defined as increased energy, decreased somnolence and sleep requirements, and improved daily function. Patients with positive responses were continued indefinitely on the medication. During the initial trial period, 31 (73%) patients had complete response and continued to take the medication. Eleven (26%) had no response. In long-term follow-up (average 17.7 months), 25 (81%) patients continued to take 100-200 mg modafinil daily. Some required an increased dosage and some took the medication as needed. Four (12%) patients stopped the medication because of side-effects or reduced efficacy; one patient (3%) stopped due to medication cost and one (3%) due to resolution of fatigue. Side-effects included insomnia, nausea, nervousness, and headaches. Modafinil appears to be a safe, effective treatment for PBC-related fatigue.

Quality of life and everyday activities in patients with primary biliary cirrhosis.

UNLABELLED: Primary biliary cirrhosis (PBC) is generally a slowly progressive disease that may lead to cirrhosis and liver failure. However, patients with PBC often suffer from a variety of symptoms long before the development of cirrhosis that include issues of daily living that have an impact on their work environment and their individual quality of life. We therefore examined multiple parameters by taking advantage of the database of our cohort of 1032 patients with PBC and 1041 matched controls. The data were obtained from patients from 23 tertiary referral centers throughout the United States and from rigorously matched controls by age, sex, ethnicity, and random-digit dialing. The data showed that patients with PBC were more likely than controls to have significant articular symptoms, a reduced ability to perform household chores, and the need for help with routine activities. Patients with PBC rated their overall activity similar or superior to that of controls; however, more of them reported limitations in their ability to carry out activities at work or at home and difficulties in everyday activities. PBC cases also more frequently reported limitations in participating in certain sports or exercises and pursuing various hobbies; however, they did not report significant limitations in social activities. In a multivariable analysis, household income, a diagnosis of systemic lupus erythematosus, limitations in work activities, a reduction in work secondary to disability, and church attendance were independently increased in PBC cases with respect to controls. CONCLUSION: Our data indicate that the quality of life of patients with PBC in the United States is generally well preserved. Nevertheless, patients with PBC suffer significantly more than controls from a variety of symptoms that are beyond the immediate impact of liver failure and affect their lifestyle, personal relationships, and work activities.

Quantitative and functional analysis of PDC-E2-specific autoreactive cytotoxic T lymphocytes in primary biliary cirrhosis.

While the pathologic mechanisms responsible for organ-specific tissue damage in primary biliary cirrhosis (PBC) remain an enigma, it has been suggested that the pathology is mediated by autoreactive T cells infiltrating the intrahepatic bile ducts. Previously, we have documented that there is 100-fold enrichment in the frequency of CD4(+) autoreactive T cells in the liver that are specific for peptides encoded by the E2 components of the pyruvate dehydrogenase complexes (PDC-E2). We have also recently characterized the first MHC class I-restricted epitope for PDC-E2, namely amino acid 159-167, a region very similar to the epitope recognized by MHC class II-restricted CD4(+) cells and by autoantibodies. The effector functions of these PDC-E2(159-167)-specific CD8(+) cytotoxic T lymphocytes (CTLs) are not well understood. We have taken advantage of tetramer technology and report herein that there is tenfold increase in the frequency of PDC-E2(159-167)-specific CTLs in the liver as compared with the blood in PBC. In addition, the precursor frequency of the CTLs in blood was significantly higher in early-stage PBC. Of interest was the fact that, upon stimulation with the peptide, the response of PDC-E2(159-167) tetramer-positive cells is heterogeneous with respect to IFN-gamma synthesis. These data, we believe for the first time, document the enrichment of autoantigen-specific CD8(+) T cells in the PBC liver, suggesting that CD8(+) T cells play a significant role in the immunopathogenesis of PBC.

The natural history of PBC: has it changed?

The prognosis and natural history of primary biliary cirrhosis (PBC) have improved significantly during the last few decades. Patients are diagnosed at earlier stages, are more likely to be asymptomatic at diagnosis, and are more likely to receive medical treatment. The survival of asymptomatic patients is longer than the median survival of symptomatic patients. The natural history of PBC has been assessed in the presence of effective therapy, ursodeoxycholic acid (UDCA). Evidence suggests that UDCA delays histological progression in PBC and decreases the risk of development of esophageal varices. Survival of UDCA-treated patients is better than that of untreated patients and also is better than that predicted by the Mayo model. For patients in early stages of PBC, UDCA treatment may normalize survival. However, patients with stage III and IV PBC do not respond as well to UDCA. Therefore, there is a continued need for additional treatment in patients with advanced disease.

Bacterial CpG induces hyper-IgM production in CD27(+) memory B cells in primary biliary cirrhosis.

BACKGROUND AND AIMS: Sera from patients with primary biliary cirrhosis (PBC) are characterized by the presence of antimitochondrial antibodies and elevated levels of immunoglobulin (Ig) M. We hypothesized that the increase in serum IgM is the result of chronic B-cell activation induced via the Toll-like receptor (TLR) signaling pathway. METHODS: We analyzed peripheral blood mononuclear cells (PBMCs) from patients with PBC and controls following incubation with CpG, a natural ligand for TLR9, and determined the basal and stimulated levels of intracellular IgM, the density of TLR9, and the contribution of specific B-cell subpopulations. RESULTS: Our data demonstrate uniquely that in vitro incubation of PBMCs from PBC with CpG-B, but not CpG-A, led to a markedly high frequency of intracellular IgM-positive B cells, associated with high levels of synthesized IgM and identified to be a function of CD27(+) memory B cells. This memory B-cell subset also expressed higher densities of TLR9 as compared with naive B cells. These results were not due to increased proliferation, as defined by 5-carboxyfluoresein diacetate succinimidyl ester labeling, or an increase in the life span of B cells, as defined by Bcl-2 expression. CONCLUSIONS: These findings for the first time identify a major role for innate immune mechanisms in the induction and persistence of abnormal humoral immune responses in PBC.