Vitamin D receptor polymorphisms and susceptibility to autoimmune liver diseases

Poster Sessions

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p < 0.001). Whole blood glutathione was unchanged. CRP, AST and ALT all showed a significant decrease (p = 0.021, p = 0.001, p < 0.001) at 3 months, which was sustained. ALP and GGT decreased significantly and steadily over the treatment period. Albumin and total antioxidant capacity only decreased after 12 months (p = 0.011, p = 0.036). Conclusions: Plasma glutathione, increasing significantly after 6 months of URSO treatment, reflects an increased, intrahepatic glutathione concentration. This, supported by the reduction in markers of inflammation and liver damage, suggests that long-term treatment with URSO may reduce oxidant stress in PBC.

~ - ~ - ] ROLE OF TNF RECEPTOR 2 EXPRESSION ON LEUKOCYTES IN EXPERIMENTAL T CELL-DEPENDENT LIVER INJURY IN MICE Jens Schuemann 1, Alexandra K. Kiemer2, Angelika M. Vollmar 2, Nico van Rooijen 3, Gisa Tiegs I . tlnstitute of Pharmacology and

Toxicology, University of Erlangen-Nuremberg, Erlangen; 2Institute of Pharmacy, Center of Drug research, PharmaceuticalBiology, University of Munich, Munich, Germany; 3Departmentof Cell Biology and Immunology, Vrije Universiteit, Amsterdam, The Netherlands We have established a novel model of T-cell-, Kupffer cell- and TNFdependent liver injury in mice, induced by Pseudomonas exotoxin A (PEA). Both TNF receptors (TNFR1 and TNFR2), are involved in the disease process. Whereas TNFR1 is well known as a cell death receptor on bepatocytes, the role of TNFR2 is less clear. TNFR2 might be either important on leukocytes to sustain inflammatory processes (NFkappaB activation, cytokine production), or on hepatocytes for cooperatively enhancing TNFRl-induced cell death. Here we show that whereas Kupffer cells and hepatocytes lost their TNFR2 molecules throughout the pathogenic process, which was paralleled by an increase of soluble TNFR2 in plasma, another strongly TNFR2 expressing CD45-positive cell type accumulated within the liver. Surprisingly, this striking TNFR2 expression on leuko-cytes did not contribute to PEA-induced liver injury (analysis of wt/TNFR2-deficient and TNFR2-deficienffwt bone marrow chimeras). Furthermore, TNFR2-deficient mice were neither deficient in producing cytokine mRNAs (real-time RT-PCR) nor in activating NF-kappaB (EMSA) within the liver. Both, production of cytokine mRNAs and activation of NF-kappaB, depended on Kupffer cells in wild-type and TNFR2-deficient mice (Kupffer cell-depletion by clodronate-liposomes). Therefore, a role of Kupffer cell-expressed TNFR2, which had to be considered because of the radioresistance of Kupffer cells in the context of generation of bone marrow chimeras, was excluded. Taken together, our results support a role of TNFR2 in T-cell-dependent liver injury by cooperatively signaling cell death in bepatocytes and not by sustaining inflammation by activating NFkappaB and/or promoting cytokine production.

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DIFFERENT IMMUNOGENETIC BACKGROUND IN AUTOIMMUNE HEPATITIS TYPE 1, TYPE 2 AND AUTOIMMUNE SCLEROSING CHOLANGITIS

James A. Underhill l , Yun Ma 2, Dimitrios P. Bogdanos 1, Paul Cbeeseman3, Giorgina Mieli-Vergani3 Diego Vergaxfil . l lnstitute of

Liver Studies, King's CollegeHospital, London; 2Institute of Hepatology, University CollegeLondon Medical School London; 3Departmentof Child Health, King's CollegeHospital, London, UK The immunogenetic profile of autoimmune hepatitis (AIH) has been mainly defined through the study of adult populations suffering from the type 1 form (AIH- 1). We have investigated HLA class I and II in 35 children with AIH-1 (22 females, age range 2.-16 yrs) and compared their results with those obtained in 31 patients with AIH-2 (25 females, 1-15 yrs) and 21 with autoimmune sclerosing cholangitis (ASC, 13 females, 2-15 yrs), a condition serologically indistinguishable from AIH-1. Class I genotyping for HLA A and B was performed using Biotest SSP/PCR kits. Class II

genotyping for HLA DRB & DQB was performed by PCR/SSO probing using oligonucleotide probes obtained from BSHI. Alleles were assigned to broad antigens to allow for relatively small sample size. In AIH- 1, there was an over-representation of HLA A*01, B*08, and DRBI*03 (63% vs 38%, p = 0.008; 62% vs 24%, p = 0.0003; 72% vs 26%, p = 0.0000002 respectively), when compared to compared with 134 previously characterised controls but also when compared to AIH-2 (63% vs 32%, p = 0.0018; 62% vs 26%, p = 0.003; 72% vs 36%, p = 0.0033) and to ASC (63% vs 42%, p = 0.014; 62% vs 26%, p = 0.013; 72% vs 19%, p = 0.00009). In AIH-2 there was an over-representation of HLA DRBI*07 (54% vs 14%, p = 0.0047) and of B'14 (23% vs 8%, p = 0.02), when compared to normal controls but also to AIH-1 (54% vs 13%, p = 0.00032; 23% vs 0%, p = 0.0037). Our results show that: a) A*01, B*08, DRB 1'03 is associated with AIH-1, but not with ASC and AIH-2, suggesting a different immunogenetic background; b) DRB 1"07 and B*14 predispose to AIH-2.

~56-5-] VITAMIN D RECEPTOR POLYMORPHISMS AND SUSCEPTIBILITY TO AUTOIMMUNE LIVER DISEASES Amdt Vogel, Christian P. Strassburg, Michael P. Mamas. Department of

Gastroenterology, Hepatology and Endocrinology, Hanaover, Germany Autoimmune hepatitis (AIH) and primary hiliary cirrhosis (PBC) are immune-mediated chronic inflammation of the liver of unknown etiology. Genetic factors and environmental triggers are assumed to contribute to the development of both diseases. A single genetic locus, which could explain the aetiology of autoimmune hepatitis or PBC, has not been identified and the genetic backgrounds are therefore considered to be polygenic. One interesting candidate gene is the Vitamin D receptor (VDR). 1,25-Dihydroxyvitamin D3 has been implicated as an immunomodulator and administration of 1,25-Dihydroxyvitamin D3 is capable to prevent the development of autoimmune diseases in animal models of autoimmune encephalomyelitis and diabetes mellitus. Polymorphisms of the VDR have been linked to a variety of autoimmune diseases. In this study VDR polymorphisms are analyzed in 127 patients with AIH, 74 patients with PBC and 214 controls. VDR polymorphisms were assessed by BsmI, TaqI, ApaI and Fok endonuclease digestion after specific PCR amplification. We found a significant association between the BsmI polymorphisms in PBC patients in comparison to controls (chi 2 = 9.49, p = 0.009). Furthermore we detected a significant association of the Fok polymorphisms in AIH patients in comparison to controls (chi 2 = 9.71, p = 0.008). In conclusion, these findings suggest a genetic link of VDR polymorphisms with PBC and AIH in German patients and contribute to the understanding of the complex events determining immunological tolerance in the liver. Further studies are needed to elucidate the mechanisms by which the vitamin D receptor contributes to the development of autnimmune diseases.

~-6-~ ASSOCIATION OF PRIMARY SCLEROSING CHOLANGITIS TO THE CTLA4 REGION ON CHROMOSOME 2q33 Kristine Wiencke l, Kirsten Mud Boberg 2, Vincent Ling 3, Hanne Harbo 4, Frode Vartdal 4, Erik Schrumpf2, Anne Spurldand 4. 1MedicalDepartment

and Institute of Immunology, National Hospital of Norway, Oslo; 2Medical Department, National Hospital of Norway, Oslo; 4Institute of Immunology, National Hospital of Norway, Oslo, Norway; 3Department of Immunology, Genetics Institute~WyethResearch, CambridgeMA, USA MHC genes contribute to disease susceptibility in primary sclerosing cholangitis (PSC), indicating an autoimmune etiology. Thus other immunoregulatory genes are candidate genes in PSC. The costimulatory receptor locus on chromosome 2q33, contains the positive T cell regulators CD28 and ICOS and the negative regulator CTLA4. CTLA4 has been implicated in susceptibility to several autoimmune diseases. It is unsettled whether PSC is associated with genes in this chromosomal region. Methods/Results: In this study we analyzed polymorphisms in the CTLA4 and ICOS (SARA47) genes as well as two additional markers in the region