Primary biliary cirrhosis shows association with genetic polymorphism of tumour necrosis factor alpha promoter region

The TNF-α rs361525 and IFN-γ rs2430561 polymorphisms are associated with liver cirrhosis risk: a comprehensive meta-analysis

Background

Inflammation serves as an essential driver of liver cirrhosis (LC) incidence. Accordingly, a meta-analysis was carried out to explore the association between specific polymorphisms in the interferon-γ (IFN-γ) and tumor necrosis factor-α (TNF-α) genes and the incidence of LC based on comparisons of genotype and allele frequencies.

Objectives

To study the relationship between TNF-α rs361525 and IFN-γ rs2430561 polymorphisms and the risk of LC.

Methods

A database search was performed for all studies published as of September 10, 2022. The strength of risk relationships was assessed based on odds ratios (ORs) with 95% confidence intervals (CIs).

Results

Pooled analyses were conducted for one common TNF-α polymorphism (rs361525) as well as one common IFN-γ polymorphism (rs2430561). Both of these SNPs were identified as LC-related risk factors. Specifically, rs361525 was related to LC incidence in both alcoholic liver cirrhosis (OR: 1.86, 95%CI: 1.03-3.34) and hepatitis B virus (HBV)-related cirrhosis cases (OR: 1.44, 95%CI: 1.00-2.06) when using an allelic contrast model. Moreover, rs2430561 was significantly related to LC in an Asian population (OR: 1.45, 95%CI: 1.13-1.86) and in the context of HBV-related cirrhosis (OR: 1.48, 95%CI: 1.13-1.93) when using an allelic contrast model.

Conclusion

These findings indicate that rs361525 and rs2430561 represent LC-related risk factors, although additional large-scale clinical and case-control studies will be vital to confirm these results.

A Meta-Analysis of the Influence of Tumor Necrosis Factor-α-308 Gene Polymorphism on Liver Cirrhosis

Cirrhosis is an active hepatic inflammation process of the liver considered as the serious phase of different liver injuries. Epidemiological studies have evaluated the possible association between TNF-α-308G/A gene polymorphism and liver cirrhosis. In this study, we have furthered the study to assess the exact association of TNF-α-308G/A gene polymorphism with liver cirrhosis susceptibility by integrating all available data. Eligible case-control studies were carried out from the establishment of the project to September 2021. Published literature from multiple databases was retrieved, collected, and analyzed by two investigators independently. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated for every study. Review Manager 5.2 and Stata 15.0 software were used for meta-analysis and stability was assessed by both subgroup analysis and sensitivity analysis. Begg's funnel plot and Egger's regression across the studies were also explored. We examined 22 case-control studies with 2683 cirrhosis patients and 2905 normal controls in four genetic models (GA vs. GG: OR = 0.95, 95%CI: (0.70, 1.30); AA vs. GG: OR = 1.11, 95% CI: (0.66, 1.85), GA + AA vs. GG: OR = 1.00, 95% CI: (0.73, 1.37); AA vs. GA + GG: OR = 1.07, 95%CI: (0.70,1.63)). TNF-α-308G/A gene polymorphism was relatively independent, and the results did not show a significant difference between the two groups. In the subgroup analysis by etiological classification of liver cirrhosis, cirrhosis after HCV infection was positively associated with the risk of TNF-α-308G/A polymorphism (AA vs. GG: OR = 3.02, 95% CI: (1.15, 7.88), AA vs. GA + GG: OR = 2.68, 95% CI: (1.04, 6.95)). The meta-analysis showed TNF-α-308G/A gene polymorphism might not have affected susceptibility for liver cirrhosis. Nevertheless, further and well-designed studies were needed to confirm the findings.

Dynamic regulation of canonical TGFβ signalling by endothelial transcription factor ERG protects from liver fibrogenesis

The role of the endothelium in protecting from chronic liver disease and TGFβ-mediated fibrosis remains unclear. Here we describe how the endothelial transcription factor ETS-related gene (ERG) promotes liver homoeostasis by controlling canonical TGFβ-SMAD signalling, driving the SMAD1 pathway while repressing SMAD3 activity. Molecular analysis shows that ERG binds to SMAD3, restricting its access to DNA. Ablation of ERG expression results in endothelial-to-mesenchymal transition (EndMT) and spontaneous liver fibrogenesis in EC-specific constitutive hemi-deficient (Erg ^cEC-Het ) and inducible homozygous deficient mice (Erg ^iEC-KO ), in a SMAD3-dependent manner. Acute administration of the TNF-α inhibitor etanercept inhibits carbon tetrachloride (CCL₄)-induced fibrogenesis in an ERG-dependent manner in mice. Decreased ERG expression also correlates with EndMT in tissues from patients with end-stage liver fibrosis. These studies identify a pathogenic mechanism where loss of ERG causes endothelial-dependent liver fibrogenesis via regulation of SMAD2/3. Moreover, ERG represents a promising candidate biomarker for assessing EndMT in liver disease.The transcription factor ERG is key to endothelial lineage specification and vascular homeostasis. Here the authors show that ERG balances TGFβ signalling through the SMAD1 and SMAD3 pathways, protecting the endothelium from endothelial-to-mesenchymal transition and consequent liver fibrosis in mice via a SMAD3-dependent mechanism.

Genome-Wide Association Studies in Primary Biliary Cirrhosis

Genome-wide association studies (GWASs) have been a significant technological advance in our ability to evaluate the genetic architecture of complex diseases such as primary biliary cirrhosis (PBC). To date, six large-scale studies have been performed that have identified 27 risk loci in addition to human leukocyte antigen (HLA) associated with PBC. The identified risk variants emphasize important disease concepts; namely, that disturbances in immunoregulatory pathways are important in the pathogenesis of PBC and that such perturbations are shared among a diverse number of autoimmune diseases-suggesting the risk architecture may confer a generalized propensity to autoimmunity not necessarily specific to PBC. Furthermore, the impact of non-HLA risk variants, particularly in genes involved with interleukin-12 signaling, and ethnic variation in conferring susceptibility to PBC have been highlighted. Although GWASs have been a critical stepping stone in understanding common genetic variation contributing to PBC, limitations pertaining to power, sample availability, and strong linkage disequilibrium across genes have left us with an incomplete understanding of the genetic underpinnings of disease pathogenesis. Future efforts to gain insight into this missing heritability, the genetic variation that contributes to important disease outcomes, and the functional consequences of associated variants will be critical if practical clinical translation is to be realized.

The accuracy of the anti-mitochondrial antibody and the M2 subtype test for diagnosis of primary biliary cirrhosis: a meta-analysis

The aim of this study was to evaluate the diagnostic value of anti-mitochondrial antibodies (AMAs) and/or the M2 subtype (AMA-M2) in patients with primary biliary cirrhosis (PBC). AMA/AMA-M2 data were obtained by searching electronic databases. Studies showing AMA/AMA-M2 results in patients with PBC and control groups with other liver diseases or healthy livers were included. The quality of the involved studies was assessed using the QUADAS tool. The pooled sensitivity and specificity were calculated, and stratified analysis was performed according to possible heterogeneity sources. The pooled AMA (all methods) sensitivity and specificity were 84.5% (95% confidence interval (CI) 83.3%-85.6%) and 97.8% (95% CI 97.6%-98.0%), respectively. The positive and negative likelihood ratios were 25.201 (95% CI 17.583-36.118) and 0.162 (95% CI 0.131-0.199), respectively. The current evidence suggests that AMA and AMA-M2 show favorable accuracy for the diagnosis of PBC with high specificity and sensitivity. AMA is a better and more comprehensive marker than AMA-M2. The accuracy established in this meta-analysis is based on clinical studies using patient cohorts from different ethnicities.

Tumour necrosis factor alpha (TNF-α) genetic polymorphisms and the risk of autoimmune liver disease: a meta-analysis

Epidemiological studies have evaluated the association between tumour necrosis factor alpha (TNF-α)- 308G/A and (TNF-α)- 238G/A polymorphisms, and the risk of autoimmune liver disease (AILD), yet the results are conflicting. To derive a more precise estimation of the relationship, we performed this meta-analysis. A systematic review was conducted to identify all eligible studies of TNF-α polymorphisms and AILD risk. We used odds ratios (ORs) with 95% confidence intervals (CIs) to assess the strength of the association between the two TNF-α polymorphisms and AILD risk. A total of 15 eligible studies were identified. Overall, positive associations of -308G/A polymorphism with AILD risk were found (A vs G allele: OR =1.45, 95%CI = 1.13- 1.86; AA vs GG: OR = 2.74, 95%CI = 1.51- 4.96; GA vs GG: OR = 1.46, 95%CI = 1.11- 1.92;dominant model: OR = 1.57, 95%CI = 1.18- 2.10; recessive model: OR = 2.22, 95%CI = 1.31- 3.76). In subgroup analysis by ethnicity, a significantly higher risk was found in Caucasians. In subgroup analysis by AILD category, significant association was observed in autoimmune hepatitis and primary sclerosing cholangitis, especially in Caucasians. Patients carrying TNF-α-238A allele had a slightly decreased risk of developing AILD (OR = 0.65, 95%CI = 0.48- 0.87). However, we found both TNF-α polymorphisms were not associated with primary biliary cirrhosis risk, even in subgroup analysis. Our meta-analysis suggests that the TNF-α-308G/A and -238G/A polymorphisms may contribute to AILD susceptibility in Caucasians,especially for autoimmune hepatitis and primary sclerosing cholangitis. Nevertheless, we found both TNF-α polymorphisms were unlikely to be associated with the risk of primary biliary cirrhosis

HLA-DR polymorphism and primary biliary cirrhosis: evidence from a meta-analysis

BACKGROUND AND AIMS

We undertook this study to review and quantitatively analyze the association between human leukocyte antigen (HLA) DR polymorphisms and susceptibility of primary biliary cirrhosis (PBC).

METHODS

All relevant publications on the association between HLA-DR polymorphisms and PBC were searched through June 2013. Odds ratios (OR) and confidence intervals (CI) for the comparisons between case and control group were calculated. Statistical analysis was performed using Stata 11.0 software.

RESULTS

Nineteen articles (or 20 studies including the substudies) were identified. For DR*7 allele, the ORs (95% CIs) were 1.530 (1.310, 1.788), 1.757 (1.285, 2.403) and 1.495 (1.211, 1.845) in overall, Asian and European populations, respectively. For DR*8 alleles, the ORs (95% CIs) were 3.158 (1.822, 5.475), 2.803 (2.420, 3.247) and 3.056 (2.573, 3.629) in Asian, American and European subgroups, respectively. The subgroup analysis for DR*11 and DR*13 showed a significant association in Asian and European population. For DR*12 and *15 alleles, the overall ORs (95% CIs) were 0.551 (0.404, 0.753) and 0.721 (0.607, 0.857). However, in subgroup analysis for DR*12 allele, the association was only found in Asian population. In addition, statistical significance exists in American and European populations in the subgroup analysis for DR*15 allele.

CONCLUSION

Our meta-analysis suggested that HLA-DR *7 and *8 allele polymorphisms contributed to the susceptibility of PBC, whereas DR*11, *12, *13 and *15 allele polymorphisms are protective factors in certain population.

TNF gene polymorphisms in cystic fibrosis patients: contribution to the disease progression

Background

It is well known that the disease progression in cystic fibrosis (CF) patients may be diverse in subjects with identical mutation in CFTR gene. It is quite possible that such heterogeneity is associated with TNF-α and/or LT-α gene polymorphisms since their products play a key role in inflammation. The aim of the study was to investigate the possible roles of TNF gene polymorphisms in CF disease phenotype and progression.

Methods

198 CF patients and 130 control subjects were genotyped for both TNF-α–308GA and LT-α + 252AG polymorphisms.

Results

The carriers of the TNF-α–308A allele more frequently had asthma as compared to patients homozygous for the TNF-α–308 G allele. In 9 of 108 (8.3%) of LTα + 252AA carriers, tuberculosis infection has been documented, whereas there was no case of tuberculosis among patients, either homozygous or heterozygous for LTα +252 G alleles (p = 0.01). We never observed virus hepatitis among LTα + 252GA carriers. The genotypes TNF-α–308GG – LT-α + 252AA and TNF-α–308GA – LT-α + 252AG were unfavorable with regard to liver disease development (both p < 0.05). It was also shown that neutrophil elastase activity was higher in sputum specimens from high TNF producers with genotypes TNF-α–308GA or LT-α + 252GG. In addition the carriers of such genotypes demonstrated a higher risk of osteoporosis development (p values were 0.011 and 0.017, respectively).

Conclusions

The carriers of genotypes, which are associated with higher TNF-α production, demonstrated increased frequency of asthma, higher levels of neutrophil elastase, and decrease of bone density. On the contrary, the carriers of genotypes associated with low TNF-α production showed a higher frequency of tuberculosis infection.

Effect of the polymorphisms of tumor necrosis factor-α gene on the susceptibility to primary biliary cirrhosis: a meta-analysis

BACKGROUND

Previous studies have shown the genetic association of tumor necrosis factor (TNF)-α polymorphisms and susceptibility to primary biliary cirrhosis (PBC), but the results of individual studies have remained contradictory. Therefore, a meta-analysis was carried out to evaluate comprehensively the association of TNF-α polymorphisms and susceptibility to PBC.

METHODS

The relevant published articles were searched in PubMed, EMBASE, and Cochrane library. Data were extracted using standardized forms and odds ratios (ORs) with 95% confidence intervals (CIs) were calculated for each study. Pooled data were estimated by fixed-effects and random-effects models when appropriate. We analyzed the association between the 'A' allele at position -308(rs1800629) and -238(rs361525) and the risk of PBC.

RESULTS

We examined eight publications, showing that all eight studies discussed the TNF-α -308(rs1800629) polymorphism; four studies were relevant with -238(rs361525). No significant associations were found between the 'A' allele frequency of rs1800629 and rs361525 and the risk of PBC in the overall population (OR=0.89, 95% CI 0.71-1.11, P=0.91; OR=0.98, 95% CI 0.66-1.47, P=0.93) and in Whites (OR=0.94, 95% CI 0.74-1.19, P=0.58; OR=1.01, 95% CI 0.64-1.59, P=0.97). Besides, it was also found that the genotype (AA+AG vs. GG, GG+AG vs. AA) was not linked to susceptibility to PBC.

CONCLUSION

The meta-analysis indicated that none of these two polymorphisms (-308G/A and -238G/A) showed any significant association with the risk of PBC.

Primary biliary cirrhosis: a multi-faced interactive disease involving genetics, environment and the immune response

Primary biliary cirrhosis (PBC) is considered a model autoimmune disease based on several features, including the presence of a highly directed and very specific immune response to mitochondrial autoantigens, a female predominance, a targeted destruction of the biliary epithelium, and homogeneity between patients. It is essentially a chronic progressive cholestatic liver disease characterized by immune-mediated destruction of small- and medium-sized intrahepatic bile ducts. There is considerable variation in the incidence and prevalence of the disease between regions of the world, although such differences likely reflect not only a true disparity in disease but also differences in awareness; for example, in the United States, PBC is often detected in an asymptomatic stage based on multi-phasic clinical testing. There has been considerable progress at defining the immune response in this disease, including quantitation of autoreactive T cells against PDC-E2, the major mitochondrial autoantigen. The overwhelming data suggests that patients develop PBC based on a genetic predisposition and loss of tolerance to one or more environmental agents. In this review, we will present an updated overview of PBC and place it in the context of autoimmunity.

Lack of an association between -308G>A polymorphism of the TNF-α gene and liver cirrhosis risk based on a meta-analysis

TNF-α is a potential proinflammatory cytokine that plays an important role in the pathogenesis of liver cirrhosis. We investigated a possible association between TNF-α -308G>A polymorphism and liver cirrhosis risk by conducting a meta-analysis. Publications addressing the association between TNF-α -308G>A and liver cirrhosis risk were selected from the Pubmed and Embase databases. Data were extracted from the studies by two independent reviewers; odds ratio (OR) with a 95% confidence interval (CI) was calculated from these data. The meta-analysis was performed by Review Manager Version 5.0.24 and STATA Version 9.2. Eleven studies were retrieved, reporting a total of 1796 liver cirrhosis cases and 2113 healthy controls. A meta-analysis of these 11 studies identified no significant association between TNF-α -308G>A polymorphism and liver cirrhosis risk in all comparisons of G vs A allele; GG vs GA + AA; GG + GA vs AA; GG vs AA; GG vs GA (OR = 1.14, 95%CI = 0.85-1.55, P = 0.38; OR = 1.24, 95%CI = 0.87- 1.77, P = 0.24; OR = 0.90, 95%CI = 0.62-1.30, P = 0.57; OR = 1.03, 95%CI = 0.56-1.89, P = 0.92; OR = 1.30, 95%CI = 0.90-1.88, P = 0.17; respectively). In conclusion, we found no association between TNF-α -308G>A polymorphism and liver cirrhosis risk, both in Caucasian and Asian populations.

Primary biliary cirrhosis

Primary biliary cirrhosis (PBC) is an idiopathic chronic autoimmune liver disease that primarily affects women. It is believed that the aetiology for PBC is a combination between environmental triggers in genetically vulnerable persons. The diagnosis for PBC is made when two of the three criteria are fulfilled and they are: (1) biochemical evidence of cholestatic liver disease for at least 6 month's duration; (2) anti-mitochondrial antibody (AMA) positivity; and (3) histologic features of PBC on liver biopsy. Ursodeoxycholic acid (UDCA) is the only FDA-approved medical treatment for PBC and should be administered at a recommended dose of 13-15 mg/kg/day. Unfortunately despite adequate dosing of UDCA, approximately one-third of patients does not respond adequately and may require liver transplantation. Future studies are necessary to elucidate the role of environmental exposures and overall genetic impact not only in the development of PBC, but on disease progression and variable clinical response to therapy.

Update on the genetics and genomics of PBC

Despite recent progress, the pathogenic mechanisms governing PBC development, treatment response and outcome remain unknown. This deficiency is in large part due to the complex nature of PBC, wherein various environmental factors may be capable of prompting disease, but only in the context of underlying genetic susceptibility. Identification of genomic loci containing these heritable risk factors has been slowed by the rarity and late onset of PBC, which has made difficult the collection of sufficient numbers of patients and family members for meaningful genetic analyses. Advancements in our ability to catalog the genetic variation in large numbers of individuals at a genome-wide scale, coupled with unprecedented efforts to recruit PBC patients for genetic study, positions us to generate data that could fundamentally change our understanding of PBC and lead to clinical innovation. Indeed, the first genome-wide association study for PBC has been published, in which multiple genes involved with IL12 signaling, a pathway that is being targeted in treatment of other inflammatory conditions, were implicated in disease. However, this study was relatively small in the genome-wide milieu and a significantly expanded effort will be necessary to truly elucidate the genetic architecture of PBC. Moving ahead, cooperation between the groups collecting biospecimens and generating genome-wide data from large numbers of patients with PBC will be essential, not only to increase power for fine mapping and future studies of rare variants and epistasis; but to streamline efforts to perform functional validation of novel discoveries. Here we provide a brief update of the current state of genetics in PBC to form a basis for understanding the considerable progress that is likely to be made in the coming years.

Carriage of a tumor necrosis factor polymorphism amplifies the cytotoxic T-lymphocyte antigen 4 attributed risk of primary biliary cirrhosis: evidence for a gene-gene interaction

Common genetic variants significantly influence complex diseases such as primary biliary cirrhosis (PBC). We recently reported an association between PBC and a single nucleotide polymorphism (rs231725) of the immunoreceptor gene cytotoxic T-lymphocyte antigen 4 (CTLA4). We hypothesized that PBC risk attributed to this polymorphism might be increased by propensity to an overly robust inflammatory response. Thus, we examined its potential interaction with the commonly studied -308AG promoter polymorphism (rs1800629) of the tumor necrosis factor (TNF) gene for which the variant TNF2A allele causes increased TNF production. The polymorphisms were genotyped in 866 PBC patients and 761 controls from independent US and Canadian registries; the effects of individual single nucleotide polymorphisms (SNPs) and their interaction on PBC risk was assessed by logistic regression. The reported association of PBC with the CTLA4 "A/A" genotype was replicated in the Canadian cohort and significant for PBC risk in the combined data (odds ratio [OR], 1.68; P = 0.0005). TNF2A allele frequency was elevated in PBC patients, but only reached borderline significance using the combined data (OR, 1.21; P = 0.042). Analysis showed that TNF2A carriage was significantly increased in CTLA4 "A/A" PBC patients compared with CTLA4 "A/A" controls (39.7% versus 16.5%, P = 0.0004); no apparent increase of TNF2A carriage was noted in CTLA4 "A/G" or "G/G" individuals. Finally, interaction under a logistic model was highly significant, as TNF2A carriage in combination with the CTLA4 "A/A" genotype was present in 6.5% of PBC patients, compared with 1.7% of controls (OR, 3.98; P < 0.0001).

CONCLUSION

TNF2A amplifies the CTLA4 rs231725 "A/A" genotype risk for PBC. Although the mechanisms remain unclear, the premise that deficiency in T-cell regulation resulting in an increased risk of PBC is amplified by overexpression of an important proinflammatory cytokine provides a basis for future functional studies.

Genomic variants associated with primary biliary cirrhosis

Primary biliary cirrhosis (PBC) is an autoimmune hepatobiliary disease characterized by immune-mediated injury of small and medium-sized bile ducts, eventually leading to liver cirrhosis. Several studies have addressed PBC immunopathology, and the data support an immune activation leading to autoantibodies and autoreactive T cells acting against the lipoylated 2-oxoacid dehydrogenase complexes. The causes of the disease remain unknown, but environmental factors and genetic susceptibility both contribute to its onset. Over the past two decades several association studies have addressed the role of genetic polymorphisms in PBC pathogenesis and have reported multiple associations. However, only a few studies had sufficient statistical power, and in most cases results were not independently validated. A genome-wide association study has recently been reported, but this too awaits independent confirmation. The aim of this present work is to critically review the numerous studies dedicated to revealing genetic associations in PBC, and to predict the potential for future studies based on these data.

TNF-alpha polymorphisms in primary biliary cirrhosis: a northern and southern Italian experience

Specific HLA alleles and immunoregulatory genes have been evaluated in primary biliary cirrhosis (PBC), but data are discordant. We determined whether TNF-alpha promoter polymorphisms (G-308A and G-238A) and alleles of HLA class II (HLA-DRB1) might be associated either with PBC occurrence and severity in Italian populations from two distinct areas. The distribution of TNF1 (G/G) genotype did not differ either between patients and controls or between patients from Northern and Southern Italy. Contrariwise, the HLA-DRB1*08 appeared positively linked to the occurrence of disease (8.4% in patients vs. 2.5% in controls, P = 0.003), whereas the HLA-DRB1*13 appeared to be protective, being more frequent in controls (12.8%) than in patients (7%) (P = 0.038). Neither positively nor negatively associated alleles of the two genomic loci had an effect on disease progression. We report a distinct genetic risk of developing PBC in the Italian population, with no interaction between the HLA and TNF alleles.

Duplication of MER115 on chromosome 4 in patients with primary biliary cirrhosis

BACKGROUND

Primary biliary cirrhosis (PBC) is a complex disease with genetic and environmental influences. The disease is more prevalent in families with PBC and candidate gene case-control studies have linked PBC with DRB1(*)08 human leucocyte antigen class II alleles.

AIMS

The goal of this study was to characterize a MER115 intergenic region on chromosome 4 as a putative genetic variant associated with PBC.

METHODS/RESULTS

This region was incidentally identified during investigations to discover candidate microbial agents using representational difference analysis (RDA) with liver samples from patients with PBC and primary sclerosing cholangitis (PSC). blast search analysis of all the RDA products from the PBC liver revealed genomic sequences, whereas Escherichia coli, mycoplasma and hepatitis B virus DNA were found in the PSC liver. We identified one of the PBC RDA products as an ancestral repeat, referred to as MER115. Southern blot analysis with the PBC product uncovered a restriction fragment length polymorphism in PBC patients' liver. Southern blot hybridization signal showed increased signal intensity in PBC vs. control patients' DNA (P<0.005) and slot blot hybridization studies confirmed a copy number variation of the MER115 in hepatic DNA of PBC vs. control patients (P=0.02).

CONCLUSIONS

Further comparative genetic studies will be required to determine the extent of genomic duplication associated with MER115 and provide data on the possible copy number variants of genes close to this intergenic region in patients with PBC.

Genetic factors of susceptibility and of severity in primary biliary cirrhosis

BACKGROUND/AIMS

In primary biliary cirrhosis (PBC), pathogenesis is influenced by genetic factors that remain poorly elucidated up to now. We investigated the impact of sequence diversity in candidate genes involved in immunity (CTLA-4 and TNFalpha), in bile formation (10 hepatobiliary transporter genes) and in the adaptative response to cholestasis (three nuclear receptor genes) on the susceptibility and severity of PBC.

METHODS

A total of 42 Ht SNPs were identified and compared in 258 PBC patients and two independent groups of 286 and 269 healthy controls. All participants were white continental individuals with French ancestry.

RESULTS

Ht SNPs of CTLA-4 and TNFalpha genes were significantly associated with susceptibility to PBC. The progression rate of liver disease under ursodeoxycholic acid (UDCA) therapy was significantly linked to SNPs of TNFalpha and SLC4A2/anion exchanger 2 (AE2) genes. A multivariate Cox regression analysis including clinical and biochemical parameters showed that SLC4A2/AE2 variant was an independent prognostic factor.

CONCLUSIONS

These data point to a primary role of genes encoding regulators of the immune system in the susceptibility to PBC. They also demonstrate that allelic variations in TNFalpha and SLC4A2/AE2 have a significant impact on the evolutive profile of PBC under UDCA therapy.

Genetics and genomics of primary biliary cirrhosis

The etiologic and pathogenic factors contributing to primary biliary cirrhosis (PBC) development, progression, response to treatment, and outcome remain a mystery. Recognition of the genomic regions harboring risk factors is hindered by the rarity and late onset of PBC. Recent advancements in genomics hold promise for understanding, prevention, and therapy of PBC. Large registries and biospecimen repositories of patients who have PBC, their family members, and controls are needed. Haplotype mapping-based association studies are necessary for defining genetic predisposition. Experimental data will provide the means for fine mapping studies, resequencing efforts, functional experimentation, and elucidation of gene-environment and gene-gene interaction.

Polymorphisms in cytokine genes and their association with acute rejection and recurrence of hepatitis B in Chinese liver transplant recipients

BACKGROUND

Acute rejection (AR) and hepatitis B virus (HBV) recurrence after liver transplantation (LT) are the two major complications leading to chronic graft dysfunction. Genomic polymorphisms in interleukin (IL)-10, tumor necrosis factor (TNF)alpha and transforming growth factor (TGF)beta1 genes have been found to affect the susceptibility to certain diseases. However, the relationship between cytokine gene polymorphisms and risk of AR as well as HBV recurrence after LT in Han Chinese has not been reported. The objective of the present study was to investigate the association of polymorphisms within these cytokine genes with the risk of AR as well as HBV recurrence.

METHODS

One hundred eighty six Chinese LT recipients in which 41 patients developed AR and 29 patients experienced HBV recurrence were enrolled; 151 age- and gender-matched healthy individuals were selected as controls. Single-nucleotide polymorphisms (SNPs) at loci of IL-10 -1082, -819, -592, and TNFalpha -308, -238, as well as TGFbeta1 -988, -800, -509, +869, and +915 were determined by using DNA sequencing and then confirmed by restriction fragment length polymorphism (PCR-RFLP). Analyses of linkage disequilibrium and haplotype frequency were performed using Haploview program.

RESULTS

The -819 and -592 polymorphisms in the IL-10 gene were in complete linkage (r(2) = 1). Another linkage was found at -509 and +869 in the TGFbeta1 gene (r(2) = 0.66). A significant difference was observed in the distribution of allelic frequencies at position -819 and -592 in the IL-10 gene between ARs and non-ARs (p = 0.036, OR = 1.134, 95% CI 0.999-1.287 and p = 0.036, OR = 1.134, 95% CI 0.999-1.287, respectively). After adjustment for a Bonferroni correction, there was no significant difference between the polymorphism and AR (p >0.05). Furthermore, the overall genotype distribution between HBV recurrence patients and non-HBV recurrence patients was also not significantly different (p >0.05).

CONCLUSIONS

Our study suggests that gene polymorphisms of IL10, TNFalpha, and TGFbeta1 do not have a major independent role in AR and HBV recurrence after LT and may not be risk factors of AR and HBV recurrence after LT in Chinese liver transplant recipients.

Possible involvement of cytokine gene polymorphisms in fulminant hepatitis

BACKGROUND AND AIM

Host genetic factors have been reported as influencing the progress to fulminant hepatitis (FH). Our previous data showed the serum level of tumor necrosis factor (TNF)-alpha influenced by gene polymorphisms to be markedly increased. It was investigated whether polymorphisms in the IL-10 gene, in addition to TNF-alpha and -beta gene polymorphisms, might contribute to the pathogenesis of FH.

METHODS

We analyzed 42 patients with FH, 78 patients with acute hepatitis (AH), and 149 healthy subjects (control). IL-10 polymorphism sites at promoter regions -1028, -819, -592; TNF-alpha polymorphism sites at promoter regions -1031, -863, -857, -308, -238; and TNF-beta first intron Nco1 sites were studied. IL-10 gene polymorphisms were classified into three groups: low IL-10-producing haplotypes (ATA/ATA), intermediate haplotypes (ATA or CCA/CCA), and high haplotypes (ATA/ATG or CCG).

RESULTS

The allelic frequency of B2 in the TNF-beta gene was significantly higher in FH patients compared with the control group. The three groups showed no differences in polymorphisms of positions -1031, -863, -857, -308 and -238 in the TNF-alpha gene. The frequency of low IL-10-producing haplotypes tended to be higher in FH patients compared with control and that of high IL-10-producing haplotype tended to be lower in FH patients compared with control. The carrier rate with both the IL-10 haplotype and the TNF-beta gene B2/B2 was significantly higher than control.

CONCLUSION

Variations of cytokine polymorphisms including IL-10 and TNF-beta genes may be attributable to the pathogenesis of FH.

Influence of TNF gene polymorphisms in Japanese patients with NASH and simple steatosis

BACKGROUND/AIMS

Tumor necrosis factor (TNF) is considered to play a role in the second hit of non-alcoholic steatohepatitis (NASH). To clarify the effects of TNF in NASH we investigated TNF gene polymorphisms that might influence TNF production were investigated.

METHODS

We analyzed 102 patients with non-alcoholic fatty liver disease (NAFLD; 36 with simple steatosis and 66 with NASH) and 100 control subjects. The serum level of soluble TNF receptor (sTNFR)-2 was measured. The TNF-alpha promoter region positions -1031, -863, -857, -308, and -238 and the TNF-beta gene Nco1 polymorphism site were investigated.

RESULTS

The level of sTNFR-2 was significantly higher in NASH patients than in those with simple steatosis or control subjects. In the analysis of TNF gene polymorphisms, there were no significant deviations between the group of all NAFLD patients and the control subjects. The carrier frequencies of polymorphisms at positions -1031C and -863A were significantly higher in patients with NASH than in those with simple steatosis. In the multivariate analysis, TNF-alpha promoter polymorphisms proved to be significant independent factors distinguishing NASH from simple steatosis.

CONCLUSIONS

TNF polymorphisms, which influence TNF production, might be associated with the progression of NAFLD.

Mapping of a disease susceptibility locus in the HLA region for Primary Biliary Cirrhosis in Japan

AIMS

Primary biliary cirrhosis (PBC) is a chronic progressive cholestatic disease of unknown pathogenesis. However, several reports have demonstrated the involvement of genetic backgrounds in this syndrome. The aim of this study is to examine the genetic disequilibrium in the HLA region in Japanese patients using six microsatellite markers.

METHODS

Genomic DNAs were obtained from 73 patients with PBC (patient cohort) and 186 healthy volunteers (control cohort). Genetic polymorphisms at six microsatellite markers (D6S1568, DQ.CAR, D6S273, TNF-d, C1-2-A, C3-2-11) were determined using fluorescence-labeled polymerase chain reaction (PCR) genetic analyzer. Allele frequencies were estimated by direct counting and the genotypic differentiation test was performed by the Markov chain method using Genepop software.

RESULTS

Among these six microsatellite markers, four markers in the patients significantly (P < 0.05) deviated from the Hardy-Weinberg equilibrium: DQ.CAR (P = 0.0278), D6S273 (P = 0.0168), TNF-d (P = 0.0089) and C1-2-A (P = 0.0005). Genotypic differentiation test between the patients and controls demonstrated that DQ.CAR (P = 0.0111), TNF-d (P = 0.0051) and C1-2-A (P = 0.0371) were significant. Finally, allelic association test revealed before correction for multiple testing demonstrated allele125 of TNF-d (P = 0.00065, Pc = 0.0052) and allele246 of C1-2-A (P = 0.0026 Pc = 0.033) had significant association after Bonferroni's correction.

CONCLUSION

Disequilibrium mapping using microsatellite markers was a useful method to narrow a disease susceptibility locus. The possible susceptibility gene in the HLA region is thought to be localized around or in the TNF gene. Further studies seem feasible using more closely distributed microsatellite markers or single nucleotide polymorphisms (SNPs) to narrow the susceptibility locus in PBC in Japanese populations.

-238 G>A polymorphism of tumor necrosis factor alpha gene (TNFA) is associated with alcoholic liver cirrhosis in alcoholic Spanish men

BACKGROUND

The tumor necrosis factor alpha gene (TNFA) has been recently associated to alcoholic steatohepatitis. We have analyzed the distribution of genotypes and alleles of two polymorphisms at positions -238 and -308 in the promoter region of the TNFA gene in a Spanish male population of alcoholics with and without alcoholic liver cirrhosis.

METHODS

149 male alcoholics (84 without alcoholic liver disease, and 65 with alcoholic liver cirrhosis) and 90 control subjects were included. Genotyping was done by polymerase chain reaction and digestion with restriction enzymes.

RESULTS

No significant differences in the distribution of genotypes and alleles of the -308 TNFA gene polymorphism were observed between alcoholics and non-alcoholics, or between alcoholics with liver cirrhosis and those without liver disease. However, we found an association between the -238 TNFA polymorphism and alcoholic liver cirrhosis; the frequency of the heterozygous genotype being significantly higher in alcoholics with cirrhosis than in those without liver damage.

CONCLUSION

The -238 TNFA-A allele is associated with a higher risk to develop alcoholic liver cirrhosis. This polymorphism could be considered as a genetic factors that confer predisposition to suffer liver cirrhosis in the alcoholic population of Castile and León.

Tumor necrosis factor-alpha -308G>A allelic variant modulates iron accumulation in patients with hereditary hemochromatosis

BACKGROUND

In vitro and animal studies suggest that tumor necrosis factor alpha (TNF-alpha) modulates intestinal iron transport. We hypothesized that the effect of TNF-alpha might be particularly relevant if iron absorption is not effectively controlled by the HFE gene.

METHODS

In patients with homozygous C282Y hemochromatosis, we investigated the influence of TNF-alpha -308G>A allelic variant on total body iron overload, determined in all patients by measuring iron removed during depletion therapy, and hepatic iron index and need for phlebotomy to prevent iron reaccumulation, measured in patient subgroups.

RESULTS

Of 86 patients with hereditary hemochromatosis, 16 (19%) were heterozygous carriers and 1 (1%) was a homozygous carrier of the TNF-alpha promoter -308A allele. Mean (SD) total body iron overload was increased 2-fold in TNF-alpha -308A allele carriers [10.9 (7.6) g] compared with homozygous carriers of the G allele [5.6 (5.0) g, P<0.001]. Hepatic iron index differed markedly between TNF-alpha -308A allele carriers [5.6 (3.5) micromol/g/year] and homozygous G allele carriers [3.1 (2.2) micromol/g/year, P=0.040, n=30]. After iron depletion, the need for phlebotomy to prevent iron reaccumulation (maintenance therapy) was substantially higher in TNF-alpha -308A allele carriers than in homozygous G allele carriers (P=0.014, n=73). We used multiple regression analyses to exclude possible confounding effects of sex, age, family screening, body-mass index, and meat or alcohol intake.

CONCLUSION

TNF-alpha -308G>A allelic variant modulates iron accumulation in patients with hereditary (homozygous C282Y) hemochromatosis, but the effect of the TNF-alpha -308A allele on clinical manifestations of hemochromatosis was less accentuated than expected from the increased iron load associated with this allele.

Genes and (auto)immunity in primary biliary cirrhosis

Primary biliary cirrhosis (PBC) is a chronic autoimmune cholestatic liver disease most commonly encountered in postmenopausal women; it is characterized by high-titer serum autoantibodies to mitochondrial antigens, elevated serum IgM, progressive destruction of intrahepatic bile ducts, and ultimately liver cirrhosis and failure. The cytopathic mechanisms leading to the selective destruction of intrahepatic cholangiocytes are still largely unknown. The current theory on the pathogenesis of PBC indicated that environmental factors might trigger autoimmunity in genetically susceptible individuals. In fact, genetic predisposition is critical to disease onset and progression, yet peculiar among autoimmune diseases, as indicated by the lack of a strong association with major histocompatibility complex haplotypes. Further, the recently reported concordance rate among monozygotic twins strengthens the importance of genetic factors, while also indicating that additional factors, possibly infectious agents or xenobiotics, intervene to trigger the disease. In this review, the available data regarding the genetic factors associated with PBC susceptibility and progression, as well as the available evidence regarding the immunomediated pathogenesis of PBC, will be critically illustrated and discussed.

From bases to basis: linking genetics to causation in primary biliary cirrhosis

Primary biliary cirrhosis (PBC) is a multifactorial autoimmune disease with inherited and environmental components in pathogenesis. It is exceptional among autoimmune diseases in showing strong heritability according to familial occurrence and monozygotic twins concordance, yet with weak associations with the usual genetic risk elements for autoimmunity, such as the HLA alleles. Among the latter, there is risk (at least in some populations) conferred by HLA DRB1*08 and possibly some protection by DRB1*11. However, the inconsistency among studies on HLA is surprising, given that PBC is a relatively homogenous disease entity. Among non-HLA genes, some studies implicate polymorphisms of genes for cytotoxic T-lymphocyte antigen-4, interleukin-2, or interleukin-10; polymorphisms of the vitamin D receptor could synergize with low sunlight exposure to create deficiency of the immunoregulatory factor, activated vitamin D. A new lead is available from the finding in female subjects with PBC of an increase in the degree of monosomy of the X chromosome that is presumed to carry immune response genes. A further suggested source of inquiry is the apparent protection of African-American women from PBC. Finally, data on inheritance should be sought in PBC by descent methodology, rather than by cross-sectional association studies in cases and control subjects, and based on analysis of a large number of families with an affected member through a worldwide effort.

Cytokine gene polymorphisms and the susceptibility to liver cirrhosis in patients with chronic hepatitis C

BACKGROUND

The speed of fibrosis progression varies considerably between patients with chronic hepatitis C. This study analyzed whether cytokine gene polymorphisms are associated with a progressive course of the disease.

METHODS

Leukocyte DNA from 101 patients with chronic hepatitis C, 52 patients with hepatitis C virus (HCV)-induced cirrhosis and 200 Caucasian blood donors was prepared. Using PCR, RFLP and PAGE, gene polymorphism analysis of the interleukin (IL)1alpha( - 889), IL1beta( - 511 and +3954), IL1 receptor agonist (RA)(intron2 VNTR), IL4(intron3 VNTR) and TNFalpha( - 308) loci was performed.

RESULTS

Of the polymorphisms analyzed, IL1beta( - 511) and IL1RA(intron2 VNTR) were unevenly distributed between the study groups. The IL1 (- 511)*A2A2 genotype occurred significantly more often in chronic hepatitis C and HCV-induced liver cirrhosis than in the controls (P < 0.01, P < 0.05, respectively). Patients with HCV-induced cirrhosis displayed a significantly higher frequency of the IL1RA(intron2 VNTR)*A2 polymorphism than patients with chronic hepatitis C and controls (P < 0.05).

CONCLUSIONS

Although the IL1beta( - 511)*A2A2 genotype may increase the susceptibility to acquire chronic hepatitis C and IL1RA(intron2 VNTR)*A2 polymorphism is associated with disease progression to cirrhosis, our results indicate that the analyzed cytokine gene polymorphisms have an overall low impact on the natural course of chronic hepatitis C infection.

Genetic factors in the pathogenesis of primary biliary cirrhosis

Current knowledge of the genetic basis of PBC is at best incomplete and at worst poor. Studies so far may be used as a guide to the pitfalls that await unwary investigators and also in deciding where to look and which genes or systems are most likely to yield informative results. The Human Genome Project has revealed a vast array of polymorphism that is too much to contemplate even with the best of current techniques. The crucial processes are the selection of candidates and study design. The strong genetic associations so far in PBC are with chromosomes 6p21.3 and 2q and include; HLA DRBI*08 haplotypes, CTLA4* G and IL1RN-IL1B haplotypes, CASP8, and nramp1. Many of the latter should be considered with caution until confirmed in independent series. Other associations with MBL, APOE and VDR remain to be confirmed. There are also several informative negatives, MMP3 and IL10 for example. It is unlikely that the only genes that influence disease susceptibility and progression in PBC are immunoregulatory genes concerned with T cell immunity. Recent studies indicate a new era for immunogenetics, when genes encoding all immune active proteins may be considered as candidates. One should not concentrate solely on the immune response as recent investigations of mannose binding lectin and apolipoprotein-E testify. One is only just beginning to understand the genetic basis of complex diseases like PBC. The key issues for future investigators are: defining the mechanisms where by self tolerance is broken, defining the mechanisms that determine the rate of disease progression, and identifying genetic markers to predict progression and malignancy. Assessing the genetic basis of variability in disease progression. The significant variation in rate of progression of PBC has led to the hypothesis that genes, in addition to contributing to disease susceptibility, may also determine the rate of disease progression. Several of the studies mentioned earlier have suggested associations between alleles at polymorphic loci and rate of progression . All studies performed to date, however, have been retrospective in nature. One problem inherent in such studies is that of definition of disease progression. One simple definition, that of histological progression to Scheuer stage IV disease , requires liver biopsy. The need to perform repeat biopsies raises ethical problems in cases where there is no other clinical indication. Studies of histologic progression in patients in the control arm of therapeutic trials represent one scenario where repeat biopsy would be indicated. However, the typical time course of such trials is 2 years, insufficient for meaningful assessment of disease progression and natural history, particularly in PBC where there is marked heterogeneity and, as a result, tissue sampling error. Yet, alternative systems for assessing disease progression, such as the Mayo prognostic score, lack sensitivity in any scenario other than existing advanced disease. Outlook for the future. Clinical observations support a significant genetic component to disease susceptibility. Elucidating predisposing genetic associations will markedly assist in understanding the pathophysiology of disease. Investigations to date have been restricted to various community-based case-control association studies, with well-recognized limitations. In future SNP maps and haplotype maps from the Human Genome Project will be available. Studies will require the collection of several well-characterized patients. To meet the required statistical power this will necessitate collaboration on a national and international scale. It is essential that these studies address the relationship between genes and disease progression. The possibility of identifying, in the early stages of disease, patients who are at elevated risk for more rapid progression, would have obvious clinical benefit in terms of patient management and therapy.

Epidemiology of autoimmune liver disease

Primary biliary cirrhosis (PBC), autoimmune hepatitis (AIH) and primary sclerosing cholangitis (PSC) are chronic liver diseases that likely have an autoimmune basis to their pathogenesis. Although significant strides have been made in the clinical management of these conditions, their pathogenesis remains obscure. Understanding of various epidemiological factors may shed light on predisposing or causative factors for these diseases. Most is known about the epidemiology of PBC, with only minimal information on that of PSC and AIH. In this review, the current data on the epidemiology of PBC, AIH and PSC are summarized and suggestions are made for future work in this important area.

Analysis of major histocompatibility complex and CTLA-4 alleles in Brazilian patients with primary biliary cirrhosis

BACKGROUND AND AIMS

Predisposition to primary biliary cirrhosis (PBC) has been classically linked to HLA-DRB1 locus. However, the presence of the HLA-DRB1*08 antigen has been reported in less than one-third of PBC patients from Northern Europe and Japan. Recently, polymorphisms in the tumor necrosis factor alpha (TNFA) gene promoter at position -308 and in exon 1 of the cytotoxic T lymphocyte antigen-4 (CTLA-4) gene at position 49 have been associated with susceptibility to PBC in Caucasians. In addition, the presence of HLA-DRB1*08 and the TNFA*1 allele was also linked to progression to end-stage liver disease. The aims of the present study were to investigate the frequencies of HLA-DR and DQ antigens and TNFA and CTLA-4 alleles in PBC patients from a different genetic background, as well as to assess the role of TNFA alleles and HLA-DR antigens in disease progression.

METHODS

Determination of HLA-DRB1, DQB1, TNFA and CTLA-4 alleles was performed in patients with PBC and healthy controls using polymerase chain reaction-based techniques.

RESULTS

Frequencies of HLA-DR and DQ antigens were similar in PBC patients and healthy controls. Accordingly, no association between TNFA and CTLA-4 alleles was observed in PBC patients. The histological stage at admission of patients with PBC also showed no correlation with HLA antigens and TNFA and CTLA-4 alleles.

CONCLUSIONS

Susceptibility to PBC in Brazil is not associated with HLA-DR and DQ antigens and CTLA-4 genotypes. TNFA alleles were not shown to influence disease progression.

Relationship between complement components C4A and C4B diversities and two TNFA promoter polymorphisms in two healthy Caucasian populations

The RP-C4-CYP21-TNX (RCCX) modules and the tumor necrosis factor (TNF) gene cluster are probably the most polymorphic genomic regions in the human central major histocompatibility complex (MHC). Using definitive methods for genotypic and phenotypic analyses of complement components C4A and C4B, determination of the RCCX length variants, and SSP-PCR/RFLP analyses of TNFA promoter polymorphisms at positions -308 and -238, we studied the complex relationships between the C4 and TNFA polymorphisms in two normal Caucasian populations. The patterns of the RCCX modular structures and the allelic frequency of -308A TNFA (TNF2) were similar between the Budapest (n = 125) and the Ohio (n = 80) Caucasians. However, the frequency of the -238A allele was significantly higher in the Ohio (11.3%) than in the Budapest (1.6%) study population (p < 0.0001). Marked features were found in the RCCX length variants in the TNF2 carriers and noncarriers. Strong associations were found between the C4AQ0 B1 haplotype from the monomodular short (mono-S) RCCX structure and the TNF2 allele, and between the C4A6 B1 haplotype from the bimodular long-short (LS) structure of the RCCX and the TNFA -238A allele. However, 36%-46% of the TNF2 carriers did not associate with a mono-S in both study cohorts, and 57.1% of the TNFA -238A carriers in Ohio did not associate with C4A6, which has a defective complement C5 convertase activity. The carriers of TNF2 allele had significantly lower C4A serum concentration (0.17 +/- 0.08 g/l) than noncarriers (0.23 +/- 0.09 g/l) (p < 0.001). The lowest C4A serum levels were found in TNF2 carriers with mono-S structures (0.14 +/- 0.06 g/l). In essence, our results demonstrated the heterogeneities of the TNFA promoter polymorphisms, and the linkage disequilibrium of TNFA -308A and -238A alleles with complement C4A deficiency and impaired C4A protein function, respectively.

Tumor necrosis factor-alpha promoter polymorphisms and the risk of rejection after liver transplantation: a case control analysis of 210 donor-recipient pairs

After orthotopic liver transplantation (OLT), allograft rejection remains an important problem and is the major reason that immunosuppressive therapy must be administered. Tumor necrosis factor-alpha (TNF-alpha) is a proinflammatory mediator that is central to the immune response, and intragraft expression of this cytokine is increased during acute cellular rejection (ACR). Polymorphisms within the TNF promoter have been identified and correlated with alterations in production. The aims of this study were to determine if an individual patient's propensity to develop ACR is related to the presence of these genetic polymorphisms (either alone or in combination) within donor and recipient tissue and to determine if these polymorphisms affect patient survival after OLT. The study group consisted of 210 patients who underwent OLT between 1989 and 1999 with at least 6 months survival, including 42 cases who had evidence of acute cellular rejection (biopsy-proven, elevated enzymes, and response to increased immunosuppression) and were matched 4:1 to controls (n = 168) with similar age, gender, underlying liver disease, date of transplant, and baseline immunosuppression. The underlying liver diseases were hepatisis C virus (HCV)/alcohol (70), HCV alone (50), alcohol (30), primary biliary cirrhosis (15), primary sclerosing cholangitis (15), autoimmune hepatitis/cirrhosis (10), cryptogenic (15), and hepatitis B virus (HBV) (5). DNA was extracted from paraffin-embedded donor and recipient liver tissue (total 420 samples), amplified, and sequenced for TNF single-nucleotide polymorphisms (TNFA-308 A/G and TNFA-238 A/G). We found no differences between the TNF allelic distributions among donors without liver disease (presumably representative of a normal control population) and patients with end-stage liver disease undergoing OLT. Multivariate analysis revealed no association with TNF polymorphisms (within donor or recipient tissue) and rejection risk or patient survival after transplantation. In this large case control analysis of patients undergoing liver transplantation for diverse etiologies, TNF promoter polymorphisms were not independently associated with rejection or survival.

Atopic asthma and TNF-308 alleles: linkage disequilibrium and association analyses

The association of a tumor necrosis factor -308 allele (TNF2) to asthma has been reported in some studies but not in others. The aim of this study was to test this association in a population recruited on the basis of allergy to Parietaria. In the study population, asthma was positively associated to HLA-DRB1*03 (p = 0.01) and to the haplotype TNF2/DRB1*03 (p = 0.02). In the parent subgroup, the proportion of asthmatics was increased in patients with TNF2 (p = 0.01), but the primary association of asthma was to the haplotype TNF2/DRB1*1104 (p = 0.005). The study population was subdivided according to prick skin test (ST) positivity to Lolium, Parietaria, and D. pteronyssinus. Asthma was associated to HLA-DRB1*03 and to the haplotype TNF2/DRB1*03 (p = 0.0015 and 0.0001, respectively) in patients ST positive to Lolium, and to the haplotype TNF2/DRB1*1104 (p = 0.025) in patients ST positive to Parietaria. The transmission disequilibrium test detected excess transmission of HLA-DRB1*03 and of the haplotype TNF2/DRB1*03 (p = 0.03 and 0.04, respectively) to siblings with asthma and ST positivity to Lolium and of HLA-DRB1*1104 and of the haplotype TNF2/DRB1*1104 (p = 0.04 and 0.015, respectively) to siblings with asthma and ST positivity to Parietaria. Taken together, these observations indicate that the haplotypes TNF2/DRB1*03 and TNF2/*B1*1104 contain alleles controlling atopic asthma in patients with sensitization to Lolium and Parietaria, respectively. This suggests that the association of asthma to TNF2 reflects linkage disequilibrium with genes influencing specific immune response.

Genetic polymorphisms and the progression of liver fibrosis: a critical appraisal

Liver fibrosis is a highly dynamic process in which multiple genes interact with environmental factors. Recent human epidemiologic studies have identified possible polymorphisms in a number of candidate genes that influence the progression of liver fibrosis. These genetic factors could explain the broad spectrum of responses to the same etiologic agent found in patients with chronic liver diseases. Polymorphisms in genes encoding immunoregulatory proteins, proinflammatory cytokines, and fibrogenic factors may influence disease progression in patients with alcohol-induced liver disease, primary biliary cirrhosis, or chronic hepatitis C. However, some of the studies have yielded contradictory results. For example, conflicting results have been obtained in studies assessing the role of mutations in the hemochromatosis gene on fibrosis progression in patients with chronic hepatitis C. Large-scale, well-designed studies are required to clarify the actual role of this factor and other genetic variants in liver fibrosis.

Influence of TNF gene polymorphism and HLA-DRB1 haplotype in Japanese patients with chronic liver disease caused by HCV

OBJECTIVE

To clarify the host genomic role in chronic liver disease associated with hepatitis C virus (HCV), we investigated the relationship between the severity of hepatitis and the polymorphisms of the tumor necrosis factor (TNF) gene or the human leukocyte antigen (HLA)-DRB1 haplotypes.

METHODS

We analyzed 40 healthy subjects, 50 patients with chronic inactive hepatitis caused by HCV with mean serum ALT concentrations under 40 IU/ml (group A), and 50 patients with chronic active liver disease caused by HCV and mean ALT concentrations over 50 IU/ml (group B).

RESULTS

There were no significant differences in the frequencies of TNF promoter gene variants at positions -238 and -308 between the groups. Regarding polymorphisms at the TNF-beta NcoI site, the frequency of B1B1 homozygotes in group A was significantly increased, compared with the healthy subjects and those in group B (controls 7.5%, group A 34%, group B 10%). Regarding the analysis of HLA-DRB1, DRB1*0901 was significantly more frequent in group A than in group B (group A 19%, group B 5%). TNF B1B1 homozygotes were associated with HLA-DRB1*0901 and *1302, and negatively associated with DRB1*0405. Combination analysis revealed that HCV was inactive in the majority of patients who were both DRB1*0901 and B1B1 homozygotes.

CONCLUSION

Our data suggest that TNF gene polymorphisms and HLA-DRB1 haplotype may influence the activity of HCV in chronic liver disease.

Genome-wide analysis of hepatic fibrosis in inbred mice identifies the susceptibility locus Hfib1 on chromosome 15

BACKGROUND & AIMS

Host genetic factors are likely to contribute to the variable course of hepatic fibrosis in response to chronic liver injury. Similarly, the fibrotic response differs among inbred mouse strains after challenge with CCl(4). Our aim was to identify unknown susceptibility loci for hepatic fibrosis in a cross between fibrosis-susceptible and -resistant inbred mice.

METHODS

Seven inbred mouse strains were treated with CCl(4), and hepatic fibrosis was phenotypically characterized by histology, hepatic hydroxyproline levels, and serum surrogate markers. F(1) hybrids of susceptible BALB/cJ and resistant A/J inbred strains were intercrossed to obtain 358 F(2) progeny. Quantitative trait loci (QTL) that determine hepatic fibrosis were identified by genome-wide interval mapping and haplotype analysis.

RESULTS

In this model, marked strain differences in fibrosis susceptibility exist, with BALB/c inbred mice being most susceptible. The hydroxyproline levels of F(1) mice resemble the resistant parental strains, indicating that fibrosis susceptibility is a recessive trait. QTL analysis identifies a susceptibility locus on chromosome 15 that significantly affects the stage of fibrosis and hydroxyproline levels. According to standard nomenclature, this locus is called Hfib1 (hepatic fibrogenic gene 1). Hfib1 is defined by genetic markers D15Mit26 and D15Mit122. A suggestive QTL on chromosome 2 colocalizes with the complement factor 5 gene, known to be mutated in the resistant strain A.

CONCLUSIONS

The set of inbred strains provides a framework for systematic analysis of fibrogenic genes. QTL mapping is useful to identify genetic susceptibility loci for hepatic fibrosis that might harbor new molecular targets for antifibrotic drug design.

Single nucleotide polymorphisms and microsatellite alleles of tumor necrosis factor alpha and interleukin-10 genes and the risk of advanced chronic alcoholic liver disease

BACKGROUND

Only a minority of ethanol abusers develop advanced chronic alcoholic liver disease (CALD). In CALD there is a imbalance between TNF alpha and IL-10, which may be modulated by several polymorphisms at both genetic loci. Our aim has been to elucidate the possible relation between these polymorphisms and the risk of CALD.

PATIENTS AND METHODS

147 patients with advanced CALD and 355 healthy controls (all white Spaniards) were included. TNF alpha biallelic single nucleotide polymorphisms (SNP) at positions -238, -308, and -376 and IL-10 biallelic SNP at positions -597, - 824, and - 1087 were investigated by polymerase chain reaction (PCR) amplification and dot blot hybridization. Moreover, polymorphic microsatellites TNFa, TNFb, IL-10.R and IL-10.G were investigated in a multiplex PCR and alleles were estimated in an automatic sequencer.

RESULTS

No differences were found in the distribution of any of the studied polymorphisms, except by an excess of the haplotype formed by the allele 11 of the microsatellite IL-10.G and the GCC arrangement of the SNPs at the promoter of IL-10 gene in patients (15.7 vs. 8.24%, odds ratio: 2.08, 95% C.I. = 1.31-3.31).

CONCLUSIONS

The studied polymorphisms at TNF alpha and IL-10 genetic loci are not clearly related to the risk of CALD. The excess of G11-GCC haplotype found in CALD patients needs independent confirmation.

Association of polymorphisms of the transforming growth factor-beta1 gene with the rate of progression of HCV-induced liver fibrosis

BACKGROUND

The objective of the present study was to elucidate possible relationships between four polymorphisms of the TGF-beta1 gene (-800G>A; -509C>T; Leu10Pro; Arg25Pro) and stage, histological activity grade and progression rate of liver fibrosis, classified according to the METAVIR-score.

METHODS

Three study groups, i.e. 48 patients with hepatic fibrosis (26 with known duration of hepatitis C virus infection), 47 patients with non-fibrotic diseases and 50 healthy blood donors, were analyzed for TGF-beta1 polymorphisms using ARMS-PCR and sequence analysis. The concentrations of total TGF-beta1 in plasma and of hyaluronan, P-III-NP and activities of transminases in serum were measured.

RESULTS

The presence of proline at codons 10 and/or 25 was associated with a faster progression of fibrosis than other polymorphisms. Patients with the genotype (25)ArgPro developed fibrosis significantly faster (0.23 units/year) than those having (25)ArgArg (0.08 units/year). Similarly, the fibrosis progression rate of patients with genotypes (10)LeuPro and (10)ProPro was almost three times as fast as of those having genotype (10)LeuLeu. Stage and histological activity grade of fibrosis in (25)ArgPro in comparison to (25)ArgArg were higher. Also (10)LeuPro showed a higher average stage of fibrosis than (10)LeuLeu. The TGF-beta1 plasma concentrations of patients with hepatic fibrosis were not significantly different between carriers of (25)ArgArg and (25)ArgPro genotypes. The frequency of the genotype (25)ArgPro in liver fibrotic patients was about three times that of the control group whereas the frequency distribution of the genotype (25)ArgArg tended to lower frequency in the fibrosis group. TGF-beta1-promoter polymorphisms did not show any correlation with stage, grade or progression of liver fibrosis.

CONCLUSION

Our results indicate that the heterozygous ArgPro of codon 25 predicts significantly faster fibrotic progression of chronic hepatitis C than the homozygous (25)ArgArg genotype. The homozygous LeuLeu genotype of codon 10 showed a slow progression of fibrosis.

Association between genetic polymorphism of tumor necrosis factor-alpha and risk of oral submucous fibrosis, a pre-cancerous condition of oral cancer

Many cytokines have been thought to play important roles in the pathogenesis of oral submucous fibrosis (OSF), an areca nut chewing-specific pre-cancerous condition characterized by the deposition of collagen in oral submucosa. Tumor necrosis factor-alpha (TNF-alpha), situated in the class III region of human leukocyte antigen (HLA), is a mediator with multiple functions, including the regulation of inflammatory reaction and transcriptions of collagen and collagenase. In total, 809 male subjects were recruited for assessment of the association of OSF with a bi-allelic promoter-region (-308) polymorphism on the TNFA gene. The high production allele, TNF2, was significantly lower among OSF subjects (n = 166) than in areca-chewing controls (n = 284). This association was independent of oral cancer status. The multivariate-adjusted odds ratio for the TNFA 11 genotype was 2.6 (95% confidence interval = 1.4-4.9; p = 0.004). The finding may imply a multifunctional etiological factor of TNF-alpha in OSF pathogenesis.

Single nucleotide polymorphisms of the mannose-binding lectin are associated with susceptibility to primary biliary cirrhosis

Although the immunopathogenesis of primary biliary cirrhosis (PBC) remains unknown, familial clustering of patients with PBC suggests an important role for genetic factors. In addition, recent data support the thesis that the mucosal immune response against intraluminal pathogens may be involved with the onset of PBC. Mannose-binding lectin (MBL) is a key factor in innate mucosal defenses and has several key single nucleotide polymorphisms (SNPs). To study whether MBL gene SNPs are associated with susceptibility to PBC, we studied 65 patients with PBC and 218 controls by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and sequence specific priming-polymerase chain reaction (SSP-PCR) to examine four polymorphic loci: two (H/L and X/Y) within the promoter region and the other two (P/Q and A/B) within exon-1. We also analyzed serum MBL concentrations. Interestingly, the prevalence of haplotype HYPA, leading to hyper-production of MBL, as well as HYPA/HYPA genotype were significantly increased in PBC compared to controls (0.53 vs. 0.44, P=0.031; 33.9%vs. 17.0%, P=0.003, respectively). Furthermore, individuals homozygous for HYPA had a significantly increased risk for PBC (odds ratio (OR)=2.51, 95% confidence interval (CI)=1.34-4.66). Our results demonstrate that the MBL genotype can be significantly associated with increased risk for PBC, and further, that increased production of MBL plays a critical role in immunopathogenesis.

Apolipoprotein E polymorphism, a marker of disease severity in primary biliary cirrhosis?

BACKGROUND/AIMS

To determine whether the apolipoprotein E (apo-E) polymorphism is associated with the risk of primary biliary cirrhosis (PBC), the severity of the disease and its response to ursodeoxycholic acid (UDCA) therapy.

METHODS

The apo-E genotype was determined in 72 PBC patients. Genotype and allele distributions were compared with those found in the French general population. Laboratory parameters obtained before and after 1- and 4-year UDCA treatment were compared according to the apo-E allele carrier status.

RESULTS

Apo-E allele and genotype distributions were similar between PBC patients and the general population. At the time of diagnosis, the epsilon4 allele carriers were younger (P < 0.05), had higher bilirubin (P < 0.05) and IgG (P < 0.001) levels and a lower prothrombin index (P < 0.01) than epsilon2 (homozygous + heterozygous) or epsilon3 homozygous allele carriers. After 4-year UDCA therapy, the decrease in serum alkaline phosphatase and in alanine and aspartate aminotransferase activities was lower in percentage in the epsilon4 than in other epsilon allele carriers (P < 0.01).

CONCLUSIONS

Although apo-E polymorphism does not appear to confer susceptibility to PBC, it probably influences PBC progression and response to UDCA. The epsilon4 allele may identify patients with high risk of severe disease and poor response to treatment.

Association of the tumour necrosis factor alpha -308 but not the interleukin 10 -627 promoter polymorphism with genetic susceptibility to primary sclerosing cholangitis

BACKGROUND AND AIMS

Primary sclerosing cholangitis (PSC) is a chronic cholestatic liver disease of unknown aetiology. Abnormalities in immune regulation and genetic associations suggest that PSC is an immune mediated disease. Several polymorphisms within the tumour necrosis factor alpha (TNF-alpha) and interleukin 10 (IL-10) promoter genes have been described which influence expression of these cytokines. This study examines the possible association between polymorphisms at the -308 and -627 positions in the TNF-alpha and IL-10 promoter genes, respectively, and susceptibility to PSC.

METHODS

TNF-alpha -308 genotypes were studied by polymerase chain reaction (PCR) in 160 PSC patients from Norway and the UK compared with 145 ethnically matched controls. IL-10 -627 genotypes were studied by PCR in 90 PSC patients compared with 84 ethnically matched controls.

RESULTS

A total of 16% of Norwegian PSC patients and 12% of British PSC patients were homozygous for the TNF2 allele compared with 3% and 6% of respective controls. The TNF2 allele was present in 60% of PSC patients versus 30% of controls (OR(combined data)=3.2 (95% confidence intervals (CI) 1.8--4.5); p(corr)=10(-5)). The association between the TNF2 allele and susceptibility to PSC was independent of the presence of concurrent inflammatory bowel disease (IBD) in the PSC patients; 61% of PSC patients without IBD had TNF2 compared with 30% of controls (OR(combined data)=3.2 (95% CI 1.2--9.0); p(corr)=0.006 ). There was no difference in the -627 IL-10 polymorphism distributions between patients and controls in either population. The increase in TNF2 allele in PSC patients only occurs in the presence of DRB1*0301 (DR3) and B8. In the combined population data, DRB1*0301 showed a stronger association with susceptibility to PSC than both the TNF2 and B8 alleles (OR(combined data)=3.8, p(corr)=10(-6) v OR(combined data)=3.2, p(corr)=10(-5) v OR(combined data )=3.41, p(corr)=10(-4), respectively).

CONCLUSIONS

This study identified a significant association between possession of the TNF2 allele, a G-->A substitution at position -308 in the TNF-alpha promoter, and susceptibility to PSC. This association was secondary to the association of PSC with the A1-B8-DRB1*0301-DQA1*0501-DQB1*0201 haplotype. No association was found between the IL-10 -627 promoter polymorphism and PSC.

Genetic and familial considerations of primary biliary cirrhosis

The genetic basis of human autoimmune diseases is receiving increasing attention. Primary biliary cirrhosis (PBC) is a model autoimmune disease reflective of other organ-specific autoimmune pathology. PBC is an enigmatic autoimmune disease that predominantly affects women and leads to destruction of intrahepatic bile ducts. The serological hallmark of this disease is characterized by antimitochondrial antibodies that specifically react with the E2 components of 2-oxodehydrogenase enzymes, including PDC-E2. There are no clear major histocompatibility complex associations with the development of PBC, despite the observation that first-degree relations of index patients with PBC have a 4-6% prevalence of development of PBC. This risk factor is comparable or higher than any other human autoimmune disease and suggests that a genome-wide approach towards dissection of genetic associations would lead to valuable new insights. In this review, we place these concepts in perspective and highlight in particular the genetic associations in PBC and the importance of studying siblings with PBC who are concordant for disease.

Immunopathogenesis of cholestatic autoimmune liver diseases

Primary biliary cirrhosis and primary sclerosing cholangitis are well recognized chronic cholestatic liver diseases that are considered to have an autoimmune basis. Recent progress in the study of autoimmune liver diseases has improved the recognition and characterization of these conditions. An important component of this progress has been the identification of liver disease-associated autoantibodies and their respective target antigens, and the development of specific assays for these autoantibodies. In addition, some nonhumoral immunological findings imply an involvement of specific immunopathogenic mechanisms in the development of these conditions. Furthermore, immunogenetic factors associated with increased susceptibility to some of these diseases have been identified. This article reviews the most relevant information relating to the postulated autoimmune pathogenesis of these diseases, with special emphasis on their associated humoral and cellular immunological abnormalities and immunopathogenetic factors. Some of the remaining important unresolved issues relating to the pathogenesis of these diseases, that need to be addressed in further research, are highlighted.

Autoimmune tests in primary biliary cirrhosis

Primary biliary cirrhosis (PBC) is characterized by an immune mediated, irreversible destruction of the small intrahepatic bile ducts leading to progressive liver cirrhosis and frequently to liver failure. The course of the disease is variable and an early diagnosis is desirable to identify individuals with rapidly progressing disease, to initiate adequate therapeutic measures and to evaluate the necessity of liver transplantation. Serological tests represent the single most important diagnostic feature of PBC because liver histology, biochemistry, or clinical syndrome alone are not reliable in this respect. The molecular definition of the autoantigen targets of antimitochondrial antibodies (AMA) has resulted in the development of reproducible and effective serological testing strategies. AMA directed against the ketoacid dehydrogenase complex are highly disease-specific but not directed against liver-specific target structures. Despite a high disease specificity, their usefulness for predicting the course of disease, the timing of liver transplantation, or disease recurrence after transplantation is limited. The realization that about 5% of patients with PBC do not display AMA has led to the identification of PBC-specific antinuclear autoantibodies directed against the nuclear pore complex and other targets. The overlap of PBC with autoimmune hepatitis and primary sclerosing cholangitis represents a diagnostic challenge in which autoantibody determinations play a central role and contribute to the administration of suitable treatment options.