IL-6 downregulates hepatic carboxylesterases via NF-κB activation in dextran sulfate sodium-induced colitis.

Ulcerative colitis (UC) is associated with increased levels of inflammatory factors, which is attributed to the abnormal expression and activity of enzymes and transporters in the liver, affecting drug disposition in vivo. This study aimed to examine the impact of intestinal inflammation on the expression of hepatic carboxylesterases (CESs) in a mouse model of dextran sulfate sodium (DSS)-induced colitis. Two major CESs isoforms, CES1 and CES2, were down-regulated, accompanied by decreases in hepatic microsomal metabolism of clopidogrel and irinotecan. Meanwhile, IL-6 levels significantly increased compared with other inflammatory factors in the livers of UC mice. In contrast, using IL-6 antibody simultaneously reversed the down-regulation of CES1, CES2, pregnane X receptor (PXR), and constitutive androstane receptor (CAR), as well as the nuclear translocation of NF-κB in the liver. We further confirmed that treatment with NF-κB inhibitor abolished IL-6-induced down-regulation of CES1, CES2, PXR, and CAR in vitro. Thus, it was concluded that IL-6 represses hepatic CESs via the NF-κB pathway in DSS-induced colitis. These findings indicate that caution should be exercised concerning the proper and safe use of therapeutic drugs in patients with UC.

Evaluation of frequency of autoimmune hepatitis autoantibodies in children with type 1 diabetes / Frecuencia de anticuerpos de hepatitis autoinmune en niños con diabetes tipo I

Background: Diabetes mellitus type 1 (T1DM) is one of the childhood diseases with growing prevalence. Various accompanying autoimmune diseases were seen with type 1 diabetes. The most common autoimmune diseases with T1DM are autoimmune thyroiditis and celiac disease. In some reports, autoimmune hepatitis has been reported in association with DM-1. Objectives: The aim of this study was to evaluate autoimmune hepatitis autoantibodies in children with T1DM. Materials and methods: In this crosssectional study, 202 children with T1DM were evaluated (47.5% were males and 52.5% were girls). Liver enzymes, autoimmune hepatitis related autoantibodies such as anti-nuclear antibodies (ANA), anti-smooth muscle (ASMA) and anti liver and kidney microsomal antibodies (LKM-1) were measured. Liver ultrasound was done for participants and biopsy of liver was taken for children with increased echogenicity of the liver, hepatomegaly or elevated liver enzymes. Results analyzed by statistical software spss-16, Descriptive statistics and chi-square test, paired T-TEST. Level of less than 5% was considered statistically significant. Results: In 6 patients ANA and in 4 patients (2%) ASMA was positive,1 patient was ASMA positive but ANA negative. None of the patients were Anti LKM-1 positive. 3 patients had positive ANA and ASMA, and increased liver echogenicity on ultrasound simultaneously. Histological evaluation was showed that 2 patients had findings in favor of autoimmune hepatitis. Conclusion: Auto antibodies were positive in 10 cases. ANA was positive in 6 (2.97%) of all cases. ASMA was positive in 4 (1.98%) cases. Increased echogenicity was found in 3 cases. Histological evaluation showed 2 patients had biopsy confirmed autoimmune hepatitis. AIH-2 was not seen among our cases.

Antecedentes: La diabetes mellitus tipo 1 (DM1) es una de las enfermedades infantiles con mayor prevalencia. Se observaron varias enfermedades autoinmunes acompañantes con diabetes tipo 1. Las enfermedades autoinmunes más comunes con DM1 son la tiroiditis autoinmune y la enfermedad celíaca. En algunos reportes, se ha encontrado hepatitis autoinmune en asociación con DM-1. Objetivos: El objetivo de este estudio fue evaluar los autoanticuerpos de hepatitis autoinmunes en niños con DM1. Materiales y métodos: En este estudio transversal, se evaluaron 202 niños con DM1 (47,5% eran hombres y 52,5% eran niñas). Se midieron las enzimas hepáticas, los autoanticuerpos autoinmunes relacionados con la hepatitis, como los anticuerpos antinucleares (ANA), el músculo liso (ASMA) y los anticuerpos microsomales hepáticos y renales (LKM-1). Se realizó una ecografía hepática para los participantes y se tomó una biopsia del hígado para niños con mayor ecogenicidad del hígado, hepatomegalia o enzimas hepáticas elevadas. Los resultados fueron analizados por el software estadístico spss-16 usando estadística descriptiva y prueba de chi-cuadrado, T-TEST pareado. Se consideró estadísticamente significativo un nivel menor del 5%. Resultados: En 6 pacientes con ANA y en 4 pacientes (2%) ASMA fue positiva, 1 paciente fue ASMA positiva pero ANA negativa. Ninguno de los pacientes fue anti LKM-1 positivo. 3 pacientes tuvieron ANA y ASMA positivas, y aumentaron la ecogenicidad hepática en la ecografía simultáneamente. La evaluación histológica mostró que 2 pacientes tenían hallazgos a favor de la hepatitis autoinmune. Conclusión: Los autoanticuerpos fueron positivos en 10 casos. ANA fue positivo en 6 (2,97%) de todos los casos. La ASMA fue positiva en 4 (1,98%) casos. Se encontró mayor ecogenicidad en 3 casos. La evaluación histológica mostró que 2 pacientes tenían biopsia confirmada de hepatitis autoinmune. AIH-2 no fue visto entre nuestros casos.

Evaluation of frequency of autoimmune hepatitis autoantibodies in children with type 1 diabetes.

BACKGROUND: Diabetes mellitus type 1 (T1DM) is one of the childhood diseases with growing prevalence. Various accompanying autoimmune diseases were seen with type 1 diabetes. The most common autoimmune diseases with T1DM are autoimmune thyroiditis and celiac disease. In some reports, autoimmune hepatitis has been reported in association with DM-1. OBJECTIVES: The aim of this study was to evaluate autoimmune hepatitis autoantibodies in children with T1DM. MATERIALS AND METHODS: In this crosssectional study, 202 children with T1DM were evaluated (47.5% were males and 52.5% were girls). Liver enzymes, autoimmune hepatitis related autoantibodies such as anti-nuclear antibodies (ANA), anti-smooth muscle (ASMA) and anti liver and kidney microsomal antibodies (LKM-1) were measured. Liver ultrasound was done for participants and biopsy of liver was taken for children with increased echogenicity of the liver, hepatomegaly or elevated liver enzymes. Results analyzed by statistical software spss-16, Descriptive statistics and chi-square test, paired T-TEST. Level of less than 5% was considered statistically significant. RESULTS: In 6 patients ANA and in 4 patients (2%) ASMA was positive,1 patient was ASMA positive but ANA negative. None of the patients were Anti LKM-1 positive. 3 patients had positive ANA and ASMA, and increased liver echogenicity on ultrasound simultaneously. Histological evaluation was showed that 2 patients had findings in favor of autoimmune hepatitis. CONCLUSION: Auto antibodies were positive in 10 cases. ANA was positive in 6 (2.97%) of all cases. ASMA was positive in 4 (1.98%) cases. Increased echogenicity was found in 3 cases. Histological evaluation showed 2 patients had biopsy confirmed autoimmune hepatitis. AIH-2 was not seen among our cases.

Nadir CD4 Is Negatively Associated With Antinuclear Antibody Detection in HCV/HIV-Coinfected Patients.

BACKGROUND: Hepatitis C virus (HCV) and HIV infections are associated with higher risk of autoimmune diseases and T-cell dysfunction. SETTING: We evaluate prevalence and factors associated with the presence of autoimmune antinuclear (ANA), anti-smooth muscle actin (aSMA), and anti-liver kidney microsome (aLKM1) antibodies (Ab) in HCV/HIV-coinfected patients during the post-combined antiretroviral therapy era. METHODS: A cross-sectional observational study nested in the ANRS CO13 HEPAVIH cohort (NCT number: NCT03324633). We selected patients with both ANA testing and T-cell immunophenotyping determination during the cohort follow-up and collected aLKM1 and aSMA data when available. Logistic regression models were built to determine factors associated with the presence of auto-Ab. RESULTS: Two hundred twenty-three HCV/HIV-coinfected patients fulfilled selection criteria. Prevalence of ANA and aSMA was 43.5% and 23.2%, respectively, and both were detected in 13.3% of patients. Isolated aSMA were detected in 9.9% and aLKM1 in 2 patients. In multivariable analysis, only a low nadir CD4 T-cell count was significantly associated with ANA detection. CONCLUSIONS: ANA and aSMA detection remain frequent in HCV/HIV-coinfected patients during the post-combined antiretroviral therapy era, despite fair immune restoration. These results advocate for a close monitoring of ANA before immune checkpoint inhibitor therapy in these patients with greater caution for those with a low nadir CD4 T-cell count.

Hepatic cytochrome P450 metabolism suppressed by mast cells in type 1 allergic mice.

Mast cells and Kupffer cells secrete interleukin (IL)-1ß, interferon (IFN)-γ, and tumor necrosis factor (TNF)-α, which stimulate excess nitric oxide (NO) producing-inducible NO synthase (iNOS). Unlike Kupffer cells, immunoglobulin E-sensitized mast cells elicit sustained NO production. We investigated the participation of mast cell-released NO and cytokine-derived iNOS activation in type 1 allergy-suppressed hepatic cytochrome P450 (CYP) metabolism. Aminoguanidine, a selective iNOS inhibitor, completely suppressed serum nitrate plus nitrite (NOx) concentrations after primary and secondary sensitization of ICR mice and markedly attenuated allergy-suppressed hepatic CYP1A2, CYP2C, CYP2E1, and CYP3A activities. In the liver, primary and secondary sensitization enhanced iNOS-stimulating IFN-γ (5-15-fold) and TNF-α (3-5-fold) mRNA levels more than IL-1ß (2-fold) and F4/80-positive Kupffer cell (2-fold) mRNA levels. When mast cell-deficient (-/-) mice were sensitized, hepatic CYP activities were not suppressed. Serum NOx levels in the sensitized -/- mice were similar with those in saline-treated ICR and -/- mice. In the liver of -/- mice, secondary sensitization markedly enhanced mRNA expression of iNOS (20-fold), IFN-γ (15-fold), and TNF-α (3-fold). However, hepatic total NOS activities in -/- mice were not significantly different between saline treatment and sensitization. Similarly, primary and secondary ICR mice did not significantly enhance total NOS activities in the liver and hepatocytes. The total NOS activities observed did not relate to the high levels of iNOS, IFN-γ, and TNF-α mRNA in the liver. Hepatic c-kit-positive mast cells in sensitized ICR mice were maintained at control levels. Therefore, our data suggest that mast cell-released NO participates in type 1 allergy-suppressed CYP1A2, CYP2C, CYP2E1, and CYP3A metabolism.

Effects of Herbal Formulas Bojungikgi-tang and Palmijihwang-hwan on Inflammation in RAW 264.7 Cells and the Activities of Drug-Metabolizing Enzymes in Human Hepatic Microsomes.

In the present study, Bojungikgi-tang (BJIKT: Buzhongyiqi-tang, Hochuekki-to) and Palmijihwang-hwan (PMJHH: Baweidìhuang-wan, Hachimijio-gan), traditional herbal formulas, investigated anti-inflammatory efficacies in murine macrophage cell line and the influence on the activities of drug-metabolizing enzymes (DMEs). The anti-inflammatory potentials of the herbal formulas were evaluated to inhibit the production of the inflammatory mediators and cytokines and the protein expression of inducible nitric oxide and cyclooxygenase-2 (COX-2) in lipopolysaccharide (LPS)-treated RAW 264.7 cells. The activities of the major human DMEs, cytochrome P450 isozymes (CYP450s) and UDP-glucuronosyltransferase isozymes (UGTs), were measured by in vitro enzyme assay systems. BJIKT and PMJHH significantly suppressed the prostaglandin E2 (PGE2) production (IC50 = 317.3 and 282.2 µg/mL, respectively) and the protein expression of COX-2 in LPS-treated RAW264.7 cells. On the human microsomal DMEs, BJIKT inhibited the activities of CYP1A2 (IC50 = 535.05 µg/mL), CYP2B6 (IC50 > 1000 µg/mL), CYP2C9 (IC50 = 800.78 µg/mL), CYP2C19 (IC50 = 563.11 µg/mL), CYP2D6 (IC50 > 1000 µg/mL), CYP2E1 (IC50 > 1000 µg/mL), CYP3A4 (IC50 = 879.60 µg/mL), UGT1A1 (IC50 > 1000 µg/mL), and UGT1A4 (IC50 > 1000 µg/mL), but it showed no inhibition of the UGT2B7 activity at doses less than 1000 µg/mL. PMJHH inhibited the CYP2D6 activity (IC50 = 280.89 µg/mL), but IC50 values of PMJHH exceeded 1000 µg/mL on the activities of CYP1A2, CYP2C19, CYP2E1, and CYP3A4. At concentrations less than 1000 µg/mL, PMJHH did not affect the activities of CYP2B6, CYP2C9, UGT1A1, UGT1A4, and UGT2B7. The results indicate that both BJIKT and PMJHH may be potential candidates to prevent and treat PGE2- and COX-2-mediated inflammatory diseases. In addition, this study will expand current knowledge about herb-drug interactions by BJIKT and PMJHH.

Detection of anti-isoniazid and anti-cytochrome P450 antibodies in patients with isoniazid-induced liver failure.

UNLABELLED: Isoniazid (INH)-induced hepatotoxicity remains one of the most common causes of drug-induced idiosyncratic liver injury and liver failure. This form of liver injury is not believed to be immune-mediated because it is not usually associated with fever or rash, does not recur more rapidly on rechallenge, and previous studies have failed to identify anti-INH antibodies (Abs). In this study, we found Abs present in sera of 15 of 19 cases of INH-induced liver failure. Anti-INH Abs were present in 8 sera; 11 had anti-cytochrome P450 (CYP)2E1 Abs, 14 had Abs against CYP2E1 modified by INH, 14 had anti-CYP3A4 antibodies, and 10 had anti-CYP2C9 Abs. INH was found to form covalent adducts with CYP2E1, CYP3A4, and CYP2C9. None of these Abs were detected in sera from INH-treated controls without significant liver injury. The presence of a range of antidrug and autoAbs has been observed in other drug-induced liver injury that is presumed to be immune mediated. CONCLUSION: These data provide strong evidence that INH induces an immune response that causes INH-induced liver injury.

Tissue-specific metabolism of benzo[a]pyrene in rainbow trout (Oncorhynchus mykiss): a comparison between the liver and immune organs.

Polycyclic aromatic hydrocarbons (PAHs) are immunotoxicants in fish. In mammals, phase I metabolites are believed to be critically involved in the immunotoxicity of PAHs. This mechanism has been suggested for fish as well. The present study investigates the capacity of immune organs (head kidney, spleen) of rainbow trout, Oncorhynchus mykiss, to metabolize the prototypic PAH, benzo[a]pyrene (BaP). To this end, we analyzed 1) the induction of enzymatic capacity measured as 7-ethoxyresorufin-O-deethylase (EROD) activity in immune organs compared with liver, 2) the organ profiles of BaP metabolites generated in vivo, and 3) rates of microsomal BaP metabolite production in vitro. All measurements were done for control fish and for fish treated with an intraperitoneal injection of 15 mg BaP/kg body weight. In exposed trout, the liver, head kidney, and spleen contained similar levels of BaP, whereas EROD induction differed significantly between the organs, with liver showing the highest induction factor (132.8×), followed by head kidney (38.4×) and spleen (1.4×). Likewise, rates of microsomal metabolite formation experienced the highest induction in the liver of BaP-exposed trout, followed by the head kidney and spleen. Microsomes from control fish displayed tissue-specific differences in metabolite production. In contrast, in BaP-exposed trout, microsomes of all organs produced the potentially immunotoxic BaP-7,8-dihydrodiol as the main metabolite. The findings from this study show that PAHs, like BaP, are distributed into immune organs of fish and provide the first evidence that immune organs possess inducible PAH metabolism leading to in situ production of potentially immunotoxic PAH metabolites.

[Use of vitamins for correction of the functional state of cytochrome P450 systems in experimental allergic encephalomyelitis].

It is known that inflammatory cytokines, which level is significantly increased in the pathogenesis of multiple sclerosis (MS), as well as interferon-beta, which is used to treat autoimmune diseases, can inhibit cytochrome P450-dependent processes of detoxification and biotransformation. The uncontrolled decrease of the activity of these processes may have a negative affect on the state of patients, so it is urgent to study the functional state of the cytochrome P450 system and to develop effective means for its regulation in these conditions. The effect of vitamin D3 and efficiency of its composition with vitamins B1, B2, B6, PP, E, alpha-lipoic, alpha-linolenoic acid and mineral substances (Mg, Zn, Se) in prevention of a functional state changes of cytochrome P450- and b5-dependent systems of the rat brain and liver endoplasmic reticulum at EAE are investigated. It has been shown that the essential decrease of the level of these cytochromes is observed both in the brain and liver. In addition the level of activity of NADH- and NADPH-oxidoreductases, which are part of microsomal electron transport chain components and coupled with monooxigenases, was reduced. These changes confirm the disturbances of a redox state and functional activity of detoxication and biotransformation systems in the studied animal tissues. Supplement of vitamin D3 as well as the composition of biologically active substances, which we developed earlier, effectively eliminated the decrease of the level of cytochromes and activities of NADH-oxidoreductase in immunised rat tissues. Normalization of these disturbances can be explained by antioxidant and membrane-stabilizing properties of applied substances, and also by the ability to reduce the activity of inflammatory reactions by regulation of the level of inflammatory cytokines in rat organism at EAE. Thus the studied vitamin-mineral composition appeared to be more effective to normalize the found disturbances and it can be useful for prevention of exacerbations and for improvement of a status of patients with multiple sclerosis and other diseases, which are accompanied with hyperactivation of immune system.

Stimulation of human monocytic THP-1 cells by metabolic activation of hepatotoxic drugs.

Drug-induced liver injury (DILI) is thought to be involved in the participation of drugs that either directly affect the cell viability or elicit an immune response. However, there is limited information about the immune responses induced by drugs, including those drugs that are metabolically activated. In this study, we constructed an in vitro assay system to assess the involvement of immune-related factors induced by metabolic activation of drugs. To investigate whether CYP3A4-mediated metabolism of 10 hepatotoxic drugs is associated with immune-related responses, human monocytic leukemia THP-1 cells were co-incubated with CYP3A4 Supersomes. Cluster of differentiation (CD) 86 and CD54 expression levels on THP-1 cells were upregulated by treatment with albendazole and amiodarone (AMD), respectively, in the presence of CYP3A4. Additionally, N-desethylamiodarone (DEA), a major metabolite of AMD, upregulated the CD54 expression of THP-1 cells with CYP3A4. The release of interleukin (IL)-8 and tumor necrosis factor (TNF) α from THP-1 cells was significantly increased by the treatment of AMD or DEA with CYP3A4. Similarly, IL-8 and TNFα were also upregulated by the treatment of AMD and DEA with human liver microsomes, but were inhibited by adding ketoconazole to the cell culture. In this study, we first report that albendazole, AMD and DEA activate immune reaction when metabolically activated.

Autoimmunity and extrahepatic manifestations in treatment-naïve children with chronic hepatitis C virus infection.

Hepatitis C virus (HCV) infection has been associated with autoimmunity and extrahepatic manifestations in adults. Few data are available on these topics in children. Nonorgan specific auto-antibodies development is part of the natural course of chronic hepatitis C in children. Smooth muscle autoantibody is the most common autoantibody found, while liver-kidney microsomal type-1 antibody positivity is the most peculiar autoimmune feature of children with HCV infection. The clinical significance of non-organ specific autoantibodies in the course of paediatric chronic hepatitis C is still debated. Autoantibody positivity can be considered neutral for most patients, while it can be associated with negative connotations for others, especially those positive for liver-kidney microsomal type-1 autoantibody. Subclinical hypothyroidism but not autoimmune thyroiditis has been demonstrated in HCV infection in children, while only few cases of HCV-associated membranoproliferative glomerulonephritis have been described. Single reports are available in the literature reporting the anecdotal association between chronic hepatitis C and other extrahepatic manifestations such as myopathy and opsoclonus-myoclonus syndrome. Despite the low incidence of extrahepatic manifestations of chronic hepatitis C in children, overall, available data suggest a careful monitoring.

Diagnostic value and utility of the simplified International Autoimmune Hepatitis Group criteria in acute-onset autoimmune hepatitis.

BACKGROUND: The diagnosis of autoimmune hepatitis (AIH) is already difficult, and that of acute-onset AIH with atypical features is even more challenging, even though the revised original diagnostic criteria created by an international AIH group were widely accepted and incorporated into clinical practice. AIMS: Recently, simplified diagnostic criteria were proposed. We compared the performance parameters of the simplified scoring system in patients with acute-onset AIH and examined its usefulness and limitations. METHODS: Fifty-five patients with acute-onset AIH (29 non-severe, 14 severe and 12 fulminant) were assessed according to the simplified scoring system and compared with the revised original one. RESULTS: Of the 55 patients, 22 (40%) were diagnosed as 'definite' AIH, 28 (51%) as 'probable' and five (9%) as 'non-diagnostic' based on the revised original scoring system. By the simplified scoring system, six (11%) were diagnosed as 'definite' AIH, 16 (29%) as 'probable' and 33 (60%) as 'non-diagnostic'. Anti-nuclear antibody titres did not differ among the three groups. The immunoglobulin G level was higher in fulminant than in non-severe patients (P = 0.01). Sixty-five per cent showed acute hepatitis (massive necrosis, submassive necrosis and severe acute hepatitis) and 35% showed chronic hepatitis. CONCLUSIONS: The revised original scoring system performed better in patients with acute-onset AIH than the simplified scoring system.

Autoantibodies for gastrointestinal organ-specific autoimmune diseases in rheumatoid arthritis patients and their relatives.

BACKGROUND: Clustering of autoimmune diseases is common and may be due to genetic background and exposition to environmental triggers. OBJECTIVE: The aim is to carry out a laboratory and clinical study of the prevalence of gastrointestinal organ-specific autoantibodies in rheumatoid arthritis (RA) patients and their relatives. METHODS: Serum samples of 156 RA patients, 200 relatives, and 100 healthy controls were studied for anti-smooth muscle antibody (ASMA), anti-mitochondrial (AMA), anti-parietal cell (APCA), anti-liver-kidney microsome (LKM), and anti-endomysium antibodies (IgA-EmA) by indirect immunofluorescence. RESULTS: A total of eight out of the 156 (5.1%) RA patients were positive for the autoantibodies (ASMA = 1; AMA = 2, APCA = 5). In the relative group, 12/200 (6%) had at least one positive autoantibody (ASMA = 1; AMA = 2, APCA = 7, IgA-EmA = 2). In the control group, two out of the 100 (2%) healthy controls were positive (ASMA = 1, APCA = 1). No statistical difference was found between RA patients, their relatives, and controls in relation to the frequency of autoantibodies evaluated. CONCLUSION: Although RA patients and their relatives have positivity of AMA, ASMA, and APCA without statistical difference in relation to healthy individuals, the findings may be of value for adequate clinical approach of these subjects.

LKM-1 sera from autoimmune hepatitis patients that recognize ERp57, carboxylesterase 1 and CYP2D6.

Liver kidney microsomal antibody type 1 (LKM-1) is a diagnostic marker for autoimmune hepatitis type 2 (AIH-2). Characterization of LKM autoantibodies of patients with AIH-2 demonstrated that a proportion of LKM sera contains autoantibodies which recognize one or more small linear epitopes on cytochrome P450, CYP2D6, an enzyme of drug metabolism pathways. The identification and epitope mapping of antigens involved in autoimmune diseases are important in understanding the mechanisms triggering autoimmunity and providing guidance for designing immunomodulatory therapy. In this study, several proteins recognized by LKM-1-positive sera in rat and human hepatic microsomes were analyzed by MALDI-TOF-MS after separation with ion-exchange chromatography or two-dimensional polyacrylamide gel electrophoresis. We identified these proteins as ERp57 and carboxylesterase 1 (CES1) as well as CYP2D6. Epitopes in ERp57 and CES1 recognized by LKM-1-positive serum were investigated by enzyme-linked immunosorbent assay (ELISA) with protease-digested peptides of ERp57 and CES1. The peptides comprising amino acids 105-129 of ERp57 and 558-566 of CES1 were specifically recognized by the serum. The epitopes in EPp57 and CES1 recognized by LKM-1-positive sera were homologous with those in hepatitis C virus (HCV). Viral infection of such as HCV may thus possibly trigger autoimmune hepatitis.

[Metabolism of 2,2',5,5'-tetrachlorobiphenyl (CB52) by rabbit liver microsomes].

Our preceding studies have reported that 2,2',5,5'-tetrachlorobiphenyl (tetraCB)(CB52) is mainly metabolized to 3-hydroxy (OH)-metabolite by phenobarbital (PB)-inducible cytochrome P450 (P450) isoforms such as CYP2B1 and CYP2B18. In this study, the metabolism of CB52 by liver microsomes of untreated and PB-treated rabbits was investigated. Rabbit liver microsomes produced mainly 3-OH- and 4-OH-metabolites (M-1 and M-2) at an equal extent and two other metabolites (M-3 and M-4) and also that phenobarbital (PB) treatment accelerated the formation of all these metabolites, M-3 was assumed to OH-tetraCB by GC-MS. Another metabolite, M-4, was determined to 3,4-diOH-CB52 by GC-MS and 1H-NMR. Addition of antiserum against CYP2B4, a constitutive and PB-inducible rabbit P450 isoform, to a microsomal incubation system resulted in almost complete inhibition of the formation of 3-OH-, 4-OH- and 3,4-diOH-metabolites. These results suggest that CYP2B4 plays an important role in CB52 metabolism in rabbit liver.

Hepatitis C virus infection acquired in childhood.

Hepatitis C virus (HCV) infection occurs less frequently in children than in adult patients, and the natural history, prognosis, and clinical significance of HCV infection in children are poorly defined. We report here a descriptive follow-up of the clinical course, biochemical data, and viral markers observed in 37 children with anti-HCV. Ten patients included in the study tested persistently negative for serum HCV-RNA (group 1) and 27 patients tested persistently positive (group 2). In group 1, serum alanine aminotransferase (ALT) was normal in all patients, while two patients had non-organ-specific autoantibodies. In group 2, serum ALT was elevated in 13 of 27 patients, and five patients had non-organ-specific autoantibodies. HCV genotype 1a and 1b were the most prevalent among HCV-RNA-positive patients. Twenty liver biopsies were carried out on 17 patients in our series (mean evolution time, 11.2 years; range, 3-21 years). The liver specimens showed mild necroinflammatory changes in most patients, and fibrosis was absent or low grade. Two HCV-RNA-positive patients became persistently HCV-RNA negative. Of the 26 children investigated, 7 (one in group 1, six in group 2) had a co-infection with hepatitis G virus. Conclusion Most children chronically infected with HCV were asymptomatic and presented only mild biochemical evidence of hepatic injury. Autoimmunity in the form of non-organ-specific autoantibodies was common. HCV in children induced mild changes in the liver with a low level of fibrosis and at a low rate of progression.

Involvement of lipid peroxidation-derived aldehyde-protein adducts in autoimmunity mediated by trichloroethene.

Lipid peroxidation, a major contributor to cellular damage, is also implicated in the pathogenesis of autoimmune diseases (AD). The focus of this study was to elucidate the role of lipid peroxidation-derived aldehydes in autoimmunity induced and/or exacerbated by chemical exposure. Previous studies showed that trichloroethene (TCE) is capable of inducing/accelerating autoimmunity. To test whether TCE-induced lipid peroxidation might be involved in the induction/exacerbation of autoimmune responses, groups of autoimmune-prone female MRL +/+ mice were treated with TCE (10 mmol/kg, i.p., every 4th day) for 6 or 12 wk. Significant increases of the formation of malondialdehyde (MDA)- and 4-hydroxynonenal (HNE)-protein adducts were found in the livers of TCE-treated mice at both 6 and 12 wk, but the response was greater at 12 wk. Further characterization of these adducts in liver microsomes showed increased formation of MDA-protein adducts with molecular masses of 86, 65, 56, 44, and 32 kD, and of HNE-protein adducts with molecular masses of 87, 79, 46, and 17 kD in TCE-treated mice. In addition, significant induction of anti-MDA- and anti-HNE-protein adduct-specific antibodies was observed in the sera of TCE-treated mice, and showed a pattern similar to MDA- or HNE-protein adducts. The increases in anti-MDA- and anti-HNE-protein adduct antibodies were associated with significant elevation in serum anti-nuclear-, anti-ssDNA- and anti-dsDNA-antibodies at 6 wk and, to a greater extent, at 12 wk. These studies suggest that TCE-induced lipid peroxidation is associated with induction/exacerbation of autoimmune response in MRL+/+ mice, and thus may play an important role in disease pathogenesis. Further interventional studies are needed to establish a causal relationship between lipid peroxidation and TCE-induced autoimmune response.

Evidence of a genetic basis for the different geographic occurrences of liver/kidney microsomal antibody type 1 in hepatitis C.

Antibodies to liver/kidney microsome type 1 occur in Italian patients with hepatitis C, but rarely develop in North American patients. Our goals were to compare the frequencies of the HLA markers associated with autoimmune expression in Italian and North American patients with chronic hepatitis C and to determine genetic bases for regional differences in antibody production. HLA B8, DR3, DR4, DR7, DR11, DR13, DQ2, and the B8-DR3-DQ2 haplotype were determined by microlymphocytotoxicity and polymerase chain reaction in 105 Italian patients (50 with microsomal antibodies), 100 North American patients (none with microsomal antibodies), and Italian and North American healthy control subjects. Italian patients with microsomal antibodies differed from North American patients without these antibodies by having a higher frequency of HLA DR7 (54% vs. 27%, P=0.002). HLA DR7 occurred more frequently in seropositive Italian patients than in seronegative counterparts (54% vs. 11% P < 0.0001), Italian healthy control subjects (54% vs. 29%, P=0.0009), and North American healthy control subjects (54% vs. 19%, P < 0.0001). The frequency of HLA DR7 was similar in North American patients and controls (27% vs. 19%, P=0.2), but it was lower than in Italian controls (19% vs. 29%, P=0.059). Seropositive Italian patients had a lower frequency of HLA DR11 than seronegative Italian patients and Italian controls (18% vs. 34%, P=0.07, and 18% vs. 35%, P=0.02, respectively). In contrast to seropositive Italian patients, North American patients had HLA DR4 (30% vs. 12%, P=0.02), HLA DR13 (29% vs. 10%, P=0.01), and the B8-DR3-DQ2 haplotype (23% vs. 6%, P=0.01) more often. Similarly, HLA DR4 and the B8-DR3-DQ2 phenotype were more frequent in North American patients than in Italian controls (30% vs. 16%, P=0.005, and 23% vs. 7%, P=0.00002, respectively). HLA DR7 is associated with the development of microsomal antibodies in Italian patients with chronic hepatitis C. The lower frequency of HLA DR7 in North America could contribute to the rarity of these antibodies in this region. HLA DR11 may be protective against the development of microsomal antibodies in Italian patients, whereas HLA DR4, HLA DR13, and the B8-DR3-DQ2 haplotype may be protective in North American patients.

High levels of autoantibodies against drug-metabolizing enzymes in SLA/LP-positive AIH-1 sera.

Autoimmune hepatitis type 1 (AIH-1) is characterized by the detection of smooth muscle autoantibodies, antinuclear antibodies and antineutrophil cytoplasmic autoantibodies, and AIH-2 is characterized by the presence of autoantibodies against LKM, which contain drug-metabolizing enzymes. In this study, we measured the levels of drug-metabolizing enzymes in AIH-1 patients (ANA-positive). We exhaustively investigated the level of autoantibodies against major CYPs and UDP-glucuronosyltransferases of typical phase II drug-metabolizing enzymes, a transporter (MDR1), and NADPH-cytochrome P450 reductase in 4 patients with AIH-1 and 6 controls, as a case report. Two (Patients 3 and 4) of the AIH patients exhibited high levels of autoantibodies, while two (Patients 1 and 2) of the patients and the controls did not. The levels of autoantibodies against CYP2C19, CYP2D6, CYP2E1, UGT1A6 and human liver microsomes in Patients 3 and 4 sera were over 2(3) times the levels in Patient 1, Patient 2 and the control sera. Meanwhile, the levels of autoantibodies against CYP1A2, CYP2A6, CYP2C9, UGT2B7, MDR1 and NADPH-cytochrome P450 reductase were 2-2(2) higher in Patients 3 and 4 than in the other subjects. We found that the pattern of elevation in the Patient 3 serum was not parallel with that in Patient 4. Thus, we found high levels of autoantibodies against drug-metabolizing enzymes in AIH-1 patients.

Multiple viral/self immunological cross-reactivity in liver kidney microsomal antibody positive hepatitis C virus infected patients is associated with the possession of HLA B51.

Liver Kidney Microsomal autoantibody type 1(LKM1) directed to cytochrome P4502D6 (CYP2D6) characterises autoimmune hepatitis type-2 (AIH-2), but is also found in a proportion of chronic hepatitis C virus (HCV) infected patients, CYP2D6252-271 being a major B- cell autoepitope. Molecular mimicry and immunological cross-reactivity between CYP2D6252-271, HCV polyprotein and the infected cell protein 4 (ICP4) of herpes simplex virus type 1 (HSV-1) have been suggested as triggers for the induction of LKM1, but reactivity and cross-reactivity to the relevant sequences have not been investigated experimentally. CYP2D6252-271 and its viral homologues were constructed and tested by ELISA in the sera of 46 chronically infected HCV patients, 23 of whom were LKM1 positive. Reactivity to the E1 HCV and ICP4 HSV1 mimics was frequently found in HCV infected patients irrespectively of their LKM1 status; viral/self cross-reactivity (as indicated by inhibition studies), however, was present in the only 2 of the 23 LKM1 seropositive HCV patients, who possessed the HLA allotype B51. Our results indicate that in HCV infected patients virus/self cross-reactivity is dependent on a specific immunogenetic background, a finding awaiting confirmation by studies in larger series of patients.