+49A/G polymorphism of cytotoxic T-lymphocyte antigen 4 gene in type 1 autoimmune hepatitis and primary biliary cirrhosis: A meta-analysis

Cytotoxic T lymphocyte antigen-4 gene polymorphisms and susceptibility to type 1 autoimmune hepatitis in the Tunisian population

Genetic factors and gene polymorphisms leading to the onset of autoimmune response in autoimmune hepatitis (AIH) are still not full elucidated. Since the CTLA-4 molecule is a key modulator of the lymphocytes responses we hypothezied that deficiencies or mutations in the gene encoding CTLA4 protein may be involved in AIH susceptibility and trigger the autoimmune response. We investigated 3 distinct polymorphic sites (+49A > G, CT60 G > A and -318C > T) of the CTLA4 gene in 50 AIH patients and 100 healthy controls using the KASP genotyping technology. A significant positive association with AIH susceptibility was found for the GG genotype in +49 position of the CTLA4 gene which was significantly higher in AIH patients compared to controls (28% vs 9%, p = 0.003, OR = 3.93 [1.56-9.88]). The CTLA4 A/A genotype in position CT60 was more significantly frequent in controls comparing to AIH patients and could be considered as a protective genotype for the tunisian patients. CTLA4 genotyping in position -318 did not show any statistically significant difference in genotype or allele distribution. The CTLA4 gene polymorphism in position +49 is associated to AIH susceptibility in the Tunisian population. Mutation in the CTLA4 gene may lead to a modification of the CTLA4 protein structure that could have functional relevance in AIH pathogenesis and onset.

Immunogenomics reveal molecular circuits of diclofenac induced liver injury in mice

Diclofenac is a non-steroidal anti-inflammatory drug and its use can be associated with severe adverse reactions, notably myocardial infarction, stroke and drug-induced liver injury (DILI). In pursue of immune-mediated DILI mechanisms an immunogenomic study was carried out. Diclofenac treatment of mice at 30 mg/kg for 3 days caused significant serum ALT and AST elevations, hepatomegaly and degenerative changes including hepatic glycogen depletion, hydropic swelling, cholesterolosis and eosinophilic hepatocytes with one animal presenting subsegmental infarction due to portal vein thrombosis. Furthermore, portal/periportal induction of the rate limiting enzyme in ammonia detoxification, i.e. carbamoyl phosphate synthetase 1 was observed. The performed microarray studies informed on > 600 differential expressed genes of which 35, 37 and 50 coded for inflammation, 51, 44 and 61 for immune and 116, 129 and 169 for stress response, respectively after single and repeated dosing for 3 and 14 days. Bioinformatic analysis defined molecular circuits of hepatic inflammation with the growth hormone (Ghr)− and leptin receptor, the protein-tyrosine-phosphatase, selectin and the suppressor-of-cytokine-signaling (Socs) to function as key nodes in gene regulatory networks. Western blotting confirmed induction of fibronectin and M-CSF to hallmark tissue repair and differentiation of monocytes and macrophages. Transcript expression of the macrophage receptor with collagenous structure increased > 7-fold and immunohistochemistry of CD68 evidenced activation of tissue-resident macrophages. Importantly, diclofenac treatment prompted strong expression of phosphorylated Stat3 amongst individual animals and the associated 8- and 4-fold Soc3 and Il-6 induction reinforced Ghr degradation as evidenced by immunoblotting. Moreover, immunohistochemistry confirmed regulation of master regulatory proteins of diclofenac treated mice to suggest complex pro-and anti-inflammatory reactions in immune-mediated hepatic injury. The findings encourage translational research.

Genetic Polymorphisms of Cytotoxic T-Lymphocyte Antigen 4 in Primary Biliary Cholangitis: A Meta-Analysis

Background and Aim

The connection between gene polymorphisms of cytotoxic T-lymphocyte-associated protein 4 (CTLA4) and primary biliary cholangitis (PBC) is still vague and blurred. The purpose of this study is to precisely estimate the association of the polymorphisms of CTLA4 with the risk of PBC by using a meta-analysis.

Methods

PubMed and the Chinese National Knowledge Infrastructure (CNKI) database were used to search correlative literatures, and the documents which were about the relationships between the polymorphisms of CTLA4 (rs231775, rs231725, rs3087243, and rs5742909) and PBC were collected as of June 2016. The strength of correlation based on odds ratios (ORs) and its 95% confidence intervals (95%CIs) was computed by STATA.

Results

Generally, in rs231775, a significant risk was found in G allele, the value of OR was 1.32, and its 95%CI was 1.19 to 1.47. The same situation was found in A allele of rs231725, the value of OR was 1.33, and its 95%CI was 1.22 to 1.45. As genotypic level, different genotypic models were also found to have obvious relevance with PBC in rs231775 and rs231725. No obvious connections were found in other SNPs.

Conclusion

This study indicated that the polymorphisms of rs231775 and rs231725 would be the risk factors of PBC.

Autoimmune hepatitis: recent advances in the pathogenesis and new diagnostic guidelines in Japan

Autoimmune hepatitis (AIH) is thought to be associated with various genetic and immunological abnormalities. Concerning the pathogenesis of AIH, increasing attention has been paid to genome-wide association studies, toll-like receptors and Treg/Th17 balance. For Japanese patients with AIH, novel diagnostic guidelines have been proposed in view of the differential clinical features between Japanese and Caucasian patients. However, the diagnosis of some patients in acute hepatitis phase is not easy. Histologically, centrilobular necrosis without portal inflammation is particularly characteristic in the acute hepatitis phase. Some patients become resistant to steroid therapy and have a very poor prognosis once they progress to acute hepatic failure. Therefore, additional revision of the current diagnostic criteria, including severity grading, will be needed in the future.

Genome-wide association study identifies variants associated with autoimmune hepatitis type 1

BACKGROUND & AIMS

Autoimmune hepatitis (AIH) is an uncommon autoimmune liver disease of unknown etiology. We used a genome-wide approach to identify genetic variants that predispose individuals to AIH.

METHODS

We performed a genome-wide association study of 649 adults in The Netherlands with AIH type 1 and 13,436 controls. Initial associations were further analyzed in an independent replication panel comprising 451 patients with AIH type 1 in Germany and 4103 controls. We also performed an association analysis in the discovery cohort using imputed genotypes of the major histocompatibility complex region.

RESULTS

We associated AIH with a variant in the major histocompatibility complex region at rs2187668 (P = 1.5 × 10(-78)). Analysis of this variant in the discovery cohort identified HLA-DRB1*0301 (P = 5.3 × 10(-49)) as a primary susceptibility genotype and HLA-DRB1*0401 (P = 2.8 × 10(-18)) as a secondary susceptibility genotype. We also associated AIH with variants of SH2B3 (rs3184504, 12q24; P = 7.7 × 10(-8)) and CARD10 (rs6000782, 22q13.1; P = 3.0 × 10(-6)). In addition, strong inflation of association signal was found with single-nucleotide polymorphisms associated with other immune-mediated diseases, including primary sclerosing cholangitis and primary biliary cirrhosis, but not with single-nucleotide polymorphisms associated with other genetic traits.

CONCLUSIONS

In a genome-wide association study, we associated AIH type 1 with variants in the major histocompatibility complex region, and identified variants of SH2B3and CARD10 as likely risk factors. These findings support a complex genetic basis for AIH pathogenesis and indicate that part of the genetic susceptibility overlaps with that for other immune-mediated liver diseases.

The association between Cytotoxic T lymphocyte associated antigen-4, Fas, tumour necrosis factor-α gene polymorphisms and autoimmune hepatitis: a meta-analysis

BACKGROUND

Several previous studies have assessed the association of Cytotoxic T Lymphocyte Associated Antigen-4, Fas, and Tumour Necrosis Factor-α gene polymorphisms with autoimmune hepatitis risk, but the results were inconsistent and inconclusive. We performed a meta-analysis to better evaluate these associations.

METHODS

PubMed, EMBASE and MEDLINE were searched in all languages. Overall odd ratios with 95% confidence intervals were calculated to assess the strength of associations using a fixed-effects or random-effects models.

RESULTS

15 relevant studies were identified. No significant association was found between CTLA-4+49A/G and AH. TNF-α-308A/G was significantly associated with autoimmune hepatitis risk. Individuals with the "A" allele had a 67% increased risk of autoimmune hepatitis (odds ratio=1.67, 95% confidence interval 1.11-2.52). The genotype "AA" was a potential predisposing factor for autoimmune hepatitis, when compared with the genotype "GG" and "AG+GG" (odds ratio=2.71, 95% confidence interval 1.12-6.57; odds ratio=2.14, 95% confidence interval 1.30-3.52). Besides, no significant association was found between the Fas-670G/A and TNF-α-238A/G polymorphisms and autoimmune hepatitis risk using any model.

CONCLUSION

The meta-analysis identified the TNF-α-308 "A" allele as a predisposing factor for autoimmune hepatitis, whereas the genotype "GG" was a protective factor. This study did not find a significant association between CTLA-4+49A/G, Fas-670G/A, TNF-α-238A/G and susceptibility to autoimmune hepatitis.

The role of vitamin d in autoimmune hepatitis

Autoimmune hepatitis is an inflammation of the liver characterized by the presence of peri-portal hepatitis, hypergammaglobulinemia, and the serum autoantibodies. The disease is classified into 2 distinct types according to the nature of auto-antibodies. Disturbances of the calcium-parathyroid hormone-vitamin D axis are frequently associated with chronic liver disease. Patients with AIH have a high prevalence of vitamin D deficiency. Genetic studies have provided the opportunity to determine which proteins link vitamin D to AIH pathology, namely, the major histocompatibility complex class II molecules, vitamin D receptors, toll-like receptors, cytotoxic T lymphocyte antigen-4, cytochrome P450 CYP2D6, regulatory T cells (Tregs) and the forkhead/winged helix transcription factor 3. Vitamin D also exerts its effect on AIH through non-genomic factors, namely, mitogen-activated protein kinase signaling pathways, γδT cells, interferon-gamma nitric oxide synthase, and reactive oxygen stress. In conclusion, vitamin D may have a beneficial role in AIH and improves liver function in concanavalin A-induced mouse AIH. Calcitriol is best used for AIH because it is the active form of a vitamin D3 metabolite and its receptors are present in sinusoidal endothelial cells, Kupffer cells, stellate cells of normal livers, and the biliary cell line.

Cytotoxic T lymphocyte antigen-4 +49A/G polymorphism does not affect susceptibility to autoimmune hepatitis

BACKGROUND & AIMS

Single nucleotide polymorphisms (SNP) in the Cytotoxic T lymphocyte antigen-4 gene (CTLA-4) have been associated with several autoimmune diseases including autoimmune Hepatitis (AIH). In this chronic idiopathic inflammatory liver disease, conflicting results have been reported on the association with a SNP at position +49 in the CTLA-4 gene in small patient cohorts. Here, we established the role of this SNP in a sufficiently large cohort of AIH patients.

METHODS

The study population consisted of 672 AIH patients derived from academic and regional hospitals in the Netherlands and was compared with 500 controls selected from the 'Genome of the Netherlands' project cohort. Genotype frequencies were assessed by PCR for patients and by whole genome sequencing for controls.

RESULTS

No significant differences in allele frequencies were found between patients and controls (G Allele: 40% vs 39%, P = 0.7). Similarly, no significant differences in genotype frequencies between patients and controls were found. Finally, there was no relation between disease activity and the G allele or AG and GG genotypes.

CONCLUSION

The Cytotoxic T Lymphocyte Antigen-4 +49 A/G polymorphism does not represent a major susceptibility risk allele for AIH in Caucasians and is not associated with disease severity at presentation.

Association of the HLA locus and TNF with type I autoimmune hepatitis susceptibility in New Zealand Caucasians

Purpose

The precise etiology of autoimmune hepatitis (AIH) remains unknown, although a number of genetic loci have been implicated in the susceptibility of type 1 AIH. The purpose of this study was to test for association of these loci with type 1 AIH in New Zealand Caucasians.

Methods

77 AIH patients and 485 healthy controls were genotyped for the SNPs rs2187668 (HLA-DRB*03:01), rs660895 (HLA-DRB*04:01), rs3749971 (HLA-A1-B8-DR3), rs231775 (CLTLA4), rs1800629 (TNF), and rs1800682 (FAS) using predesigned TaqMan SNP genotyping assays. Chi square analysis was used to test for association of allele and genotype with overall AIH, and with severe fibrosis and ALT levels at 6 months.

Results

Significant risk of AIH was conferred by the minor alleles of rs2187668 (OR = 2.45, 95% CI 1.65-3.61, p < 0.0001), rs3749971 (OR = 1.89, 95% CI 1.21-2.94, p = 0.004) and rs1800629 (OR = 2.06, 95% CI 1.41-3.01, p = 0.0001). Multivariate analysis showed that rs2187668 was independently associated with type 1 AIH susceptibility (OR = 2.40, 95% CI 1.46-3.93, p = 0.001). The C allele of FAS SNP rs1800682 was associated with increased risk of severe fibrosis at diagnosis (OR = 2.03, 95% CI 1.05-3.93, p = 0.035) and with incomplete normalization of ALT levels at 6 months post-diagnosis (OR = 3.94, 95% CI 1.62-9.54, p = 0.0015).

Conclusions

This is the first population-based study to investigate genetic risk loci for type 1 AIH in New Zealand Caucasians. We report significant independent association of HLA-DRB1*03:01 with overall susceptibility to type 1 AIH, as well as FAS with a more aggressive disease phenotype.

Association between cytotoxic T-lymphocyte-associated antigen 4 +49A/G polymorphism and persistent hepatitis B virus infection in the Asian population: evidence from the current studies

AIMS

A number of studies assessed the association between cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) +49A/G polymorphism and persistent hepatitis B virus (HBV) infection risk. However, the results are quite contradictory. In order to obtain a more precise estimation of the relationship, a meta-analysis was performed.

METHODS

Pubmed, ISI Web of Knowledge, HuGE Navigator, Wanfang Database, and China National Knowledge Infrastructure were searched. Crude odds ratios (ORs) with 95% confidence intervals (95% CIs) were calculated to estimate the strength of this association.

RESULTS

Six publications were included in the final meta-analysis with 1075 cases and 1321 controls for CTLA-4 +49A/G polymorphism according to our inclusion and exclusion criteria. We observed that the CTLA-4 +49A/G polymorphism was significantly correlated with chronic HBV infection risk (the homozygote codominant model: OR 1.67, 95% CI 1.30-2.15; the dominant model: OR 1.34, 95% CI 1.01-1.78; the recessive model: OR 1.56, 95% CI 1.24-1.96; the allele contrast model: OR 1.32, 95% CI 1.10-1.59). No publication bias was observed in this study according to Begg's funnel plot and Egger's test.

CONCLUSION

CTLA-4 +49A/G polymorphism is assumed to confer a higher risk for persistent HBV infection in the Asian population.

The role of vitamin d in primary biliary cirrhosis: possible genetic and cell signaling mechanisms

Primary biliary cirrhosis (PBC) is an immune-mediated chronic inflammatory disease of the liver of unknown etiology. Vitamin D deficiency is highly prevalent in patients with PBC, and many studies have demonstrated the significant effect of calcitriol on liver cell physiology. Vitamin D has antiproliferative and antifibrotic effects on liver fibrosis. Genetic studies have provided an opportunity to determine which proteins link vitamin D to PBC pathology (e.g., the major histocompatibility complex class II molecules, the vitamin D receptor, toll-like receptors, apolipoprotein E, Nramp1, and cytotoxic T lymphocyte antigen-4). Vitamin D also exerts its effect on PBC through cell signaling mechanisms, that is, matrix metalloproteinases, prostaglandins, reactive oxygen species, and the transforming growth factor betas. In conclusion, vitamin D may have a beneficial role in the treatment of PBC. The best form of vitamin D for use in the PBC is calcitriol because it is the active form of vitamin D3 metabolite, and its receptors are present in the sinusoidal endothelial cells, Kupffer cells, and stellate cells of normal livers, as well as in the biliary cell line.

Recipient cytotoxic T lymphocyte antigen 4 +49 single-nucleotide polymorphism is not associated with acute rejection after liver transplantation in Chinese population

OBJECTIVE

Single-nucleotide polymorphisms (SNPs) in Cytotoxic T lymphocyte antigen 4 (CTLA-4) gene have been detected and proved to associate with the incidence of rejection after transplantation. However, previous studies gained inconsistent results about the association between CTLA-4 +49 single-nucleotide polymorphism and susceptibility of allograft rejection. Therefore we sought to clarify whether CTLA-4 +49 SNP influences the incidence of acute rejection after liver transplantation in Chinese population.

METHODS

Genomic DNA from 335 liver transplant recipients was genotyped for CTLA-4 +49 SNP by DNA sequencing. Acute rejection was confirmed by pathologic evidences. The association between CTLA-4 +49 SNP and incidence of acute rejection was then analyzed by dominant, recessive, codominant and overdominant models.

RESULTS

The incidence of acute rejection within the first 3 months was 11.9%. In acute rejectors, the frequency was 45% for G/G, 10% for A/A and 45% for A/G respectively, compared with 47.5% for G/G, 10.8% for A/A and 41.7% for A/G in non-acute rejectors. And no significant difference of allele distribution between these 2 groups was detected.

CONCLUSIONS

This study suggests that CTLA-4 +49 SNP is not associated with acute rejection after liver transplantation in Chinese population.

Cutting edge: chronic inflammatory liver disease in mice expressing a CD28-specific ligand

Inflammation of the normally tolerant liver microenvironment precedes the development of chronic liver disease. Study of the pathogenesis of autoimmune liver diseases, such as autoimmune hepatitis (AIH), has been hampered by a lack of autochthonous chronic animal models. Through our studies of T cell costimulation, we generated transgenic mice expressing a ligand specific for the CD28 receptor, which normally shares ligands with the related inhibitory receptor CTLA-4. The mice spontaneously develop chronic inflammatory liver disease with several pathologies found in AIH, including elevated serum aminotransferases in the context of normal alkaline phosphatase and bilirubin levels, lymphocytic inflammation, focal necrosis, oval cell hyperplasia, and fibrosis. The prevalence of IFN-γ-producing CD8(+) T cells in the livers of transgenic mice suggests a role for autoimmune cytotoxicity in the chronic disease state. The CD28 ligand-specific transgenic mice will facilitate evaluation of CD8(+) T cell function in liver disease pathologies found in AIH.

Recent advances in understanding the pathogenesis of primary biliary cirrhosis

Primary biliary cirrhosis (PBC) is a chronic progressive cholestatic autoimmune liver disease characterized by the destruction of small intrahepatic bile ducts and the presence of highly specific serum antimitochondrial antibodies (AMAs). The human leukocyte antigen (HLA) gene has been proved to have strongest association with PBC susceptibility, and non-HLA genes, including IL12A, IL12RB2, STAT4, IRF5-TNPO3, ORMDL3/IKZF3, MMEL1, SPIB, CTLA-4, FCRL3 and A2BP1, are also closely associated with PBC susceptibility. Four AMAs including anti-M2, anti-M4, anti-M8 and anti-M9, and antinuclear antibodies (ANAs), such as antinuclear dot antibodies (SP100, PML, NDP52, SP140), antinuclear pore antibodies (gp210, p62), antinuclear envelope antibodies (Lamin and Lamin B receptor), and anti-centromere antibodies, may also be involved in the pathogenesis of PBC. The imbalance between Th17 cells and regulatory T lymphocytes (Treg) may also play an important role in the pathogenesis of PBC. In addition, senescence, autophagy, apoptosis of biliary epithelial cells (BECs), and environmental factors, such as Epstein-Barr virus (EBV) infection and smoking, may also contribute to the pathogenesis of PBC. Understanding of the mechanisms responsible for the pathogenesis of PBC has important implications for the treatment of PBC.

Cytotoxic T-lymphocyte associated antigen 4 polymorphisms and asthma risk: a meta-analysis

Background

A number of studies assessed the association of cytotoxic T-lymphocyte associated antigen 4 (CTLA-4) gene polymorphisms with asthma in different populations. However, the results were contradictory. We performed a meta-analysis to examine the association between CTLA-4 polymorphisms and asthma susceptibility.

Methods

Pubmed, EMBASE, HuGE Navigator, and Wanfang Database were searched. Data were extracted independently by two reviewers. Odds ratios (ORs) with 95% confidence intervals (CIs) were used to assess the strength of associations.

Results

Seventeen studies involving 6378 cases and 8674 controls were included. Significant association between +49 A/G polymorphism and asthma was observed for AA vs. AG+GG (OR = 1.18, 95% CI 1.01–1.37, P = 0.04). There were no significant associations between −318 C/T, −1147 C/T, CT60 A/G, −1722 C/T, or rs926169 polymorphisms and asthma risk.

Conclusions

This meta-analysis suggested that the +49 A/G polymorphism in CTLA-4 was a risk factor for asthma.

Cytotoxic T-lymphocyte associated antigen-4 gene polymorphisms and primary biliary cirrhosis: a systematic review

BACKGROUND AND AIM

The cytotoxic T-lymphocyte antigen 4 (CTLA4) is an inhibitory receptor expressed on activated and regulatory T lymphocytes. Polymorphisms could have remarkable effects on susceptibility to autoimmunity. However, the associations between CTLA-4 polymorphisms and primary biliary cirrhosis (PBC) remain ambiguous. The aim of this meta-analysis is to determine more precise estimations of the relationship.

METHODS

From literature retrieval from PubMed, Web of Science, Science Direct, and the Chinese National Knowledge Infrastructure (CNKI) Database, the publications on the associations between rs231775, rs3087243, rs5742909, rs231725 and rs11571317 polymorphisms of CTLA4 and PBC through June 2011 were collected. Odds ratios (OR) with 95% confidence intervals (95% CI) were calculated in fixed or random model, I(2) was calculated to examine heterogeneity, and funnel plots were plotted to examine small study effects with Revman 5.1 and Stata 11.

RESULTS

Overall, a significantly increased risk was found for G versus A allele for rs231775 (OR = 1.28, 95% CI = 1.17-1.41). For rs3087243, a significant association was found for AA versus GG genotype (OR = 0.66; 95% CI = 0.55-0.80). When subgroup analysis by ethnicity was performed, the same association was only found in Caucasians. For rs231725, the OR values (95% CI) for GG versus AA, GA versus AA and G versus A allele were 0.52 (0.40-0.68), 0.74 (0.60-0.92) and 0.73 (0.61-0.88). No significant associations were found for other polymorphisms.

CONCLUSION

The G allele of rs231775 is a risk factor for PBC, while AA genotype of rs3087243 and GG, GA and G allele of rs231725 show negative associations with 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.

Association of polymorphisms in non-classic MHC genes with susceptibility to autoimmune hepatitis

BACKGROUND

Autoimmune hepatitis is a chronic, generally progressive inflammatory disorder of the liver, of which the cause is unclear. It was demonstrated that genetic factors are involved in its pathogenesis. Previous studies showed that human leukocyte antigen in the major histocompatibility complex (MHC) is associated with susceptibility to autoimmune hepatitis. Current genome scanning studies suggest that genes outside the MHC also play a critical role in autoimmune disorders. This article focuses on our current understanding of the polymorphisms of these genes and their roles in the pathogenesis of autoimmune hepatitis.

DATA SOURCES

Studies were identified by searching MEDLINE and PubMed for articles using the keywords autoimmune hepatitis, polymorphism, CTLA-4, Fas, TNF-alpha, TGF-beta1, TBX21 and VDR up to May 2011. Additional papers were identified by a manual search of the references from key articles.

RESULTS

According to the case-control studies on genetic polymorphisms, at least six genes (CTLA-4, Fas, TNF-alpha, TGF-beta1, TBX21 and VDR) are involved in autoimmune hepatitis besides HLA. So far, there has been no agreement about gene susceptibility and the actual clinical significance of these genes is still controversial.

CONCLUSION

Studies on gene polymorphisms outside the MHC and knowledge of genetic predispositions for autoimmune hepatitis may not only elucidate pathogenic mechanisms, but also provide new targets for therapy in the future.

Cytotoxic T-lymphocyte antigen 4 gene +49A/G polymorphism significantly associated with susceptibility to primary biliary cirrhosis: a meta-analysis

OBJECTIVE

To evaluate comprehensively the association of cytotoxic T-lymphocyte antigen 4 (CTLA-4) +49A/G polymorphism with susceptibility to primary biliary cirrhosis (PBC).

METHODS

PubMed was used to search for the relevant published articles. The risk of PBC association with the CTLA-4+49A/G polymorphism was estimated for each study in a random-effects model. Odds ratio (OR) and 95% confidence interval (CI) were estimated for each study. Risks to PBC were estimated by stratified analysis in patients with different ethnicity and antimitochondrial antibody (AMA) status, as well as histological stages.

RESULTS

A total of 12 articles were included in the study. An association between PBC and CTLA-4 G allele was found, overall OR = 1.20, 95% CI 1.03-1.41 (P = 0.02). However, stratification by ethnicity indicated a significant association between the G allele and PBC in Asians (OR = 1.36, 95% CI 1.12-1.65, P = 0.002), but not in Caucasians (OR = 1.15, 95% CI 0.95-1.39, P = 0.15). Moreover, AMA positive patients carrying G allele were more susceptible to PBC compared with AMA negative patients (OR = 1.23, 95% CI 1.06-1.43, P = 0.007; OR = 0.98, 95% CI 0.71-1.34, P = 0.88, respectively).

CONCLUSIONS

Polymorphism in exon 1 of CTLA-4 gene at position 49 may act as a candidate of susceptibility locus to PBC. However, larger studies with participants of varying ethnicity and stratified by clinical and laboratory characteristics are needed to validate our findings.

Association between CTLA-4 exon-1 +49A>G polymorphism and primary biliary cirrhosis risk: a meta-analysis

BACKGROUND AND AIMS

CTLA-4 exon-1 +49A>G polymorphisms have been reported to influence the risk for primary biliary cirrhosis in many studies; however, the results still remain controversial and ambiguous. The aim of this study was to determine more precise estimations for the relationship between CTLA-4 exon-1 +49A>G polymorphisms and the risk for primary biliary cirrhosis.

METHODS

Electronic searches for all publications were conducted on associations between this variant and breast cancer in several databases through November 2010. Crude odds ratios (ORs) with 95% confidence intervals (CIs) were calculated to estimate the strength of the association. Eight studies were identified including 2151 cases and 2214 controls.

RESULTS

Overall, there were no significant associations between CTLA +49G>A polymorphism and primary biliary cirrhosis risk (codominant model: GA vs. AA OR=1.190, 95% CI=0.818-1.732; GG vs. AA OR=1.153, 95% CI=0.858-1.550; dominant model: OR=1.181, 95% CI=0.873-1.599; and recessive model: OR=1.148; 95% CI=0.903-1.459). In the subgroup analysis by ethnicity, a significantly increased risk was found for Asians (GG vs. AA OR=1.873; 95% CI=1.202-2.921) and recessive model (OR=1.758; 95% CI = 1.271-2.433). In the stratified analysis by control sources, significant association were observed in population-based studies (GA vs. AA OR=1.432; 95% CI=1.078-1.902).

CONCLUSIONS

This meta-analysis suggests that the CTLA-4 +49G>A polymorphism may be a risk factor for primary biliary cirrhosis in Asians.