Association of cytotoxic T-lymphocyte antigen 4 gene polymorphisms with type 1 autoimmune hepatitis in Japanese

IgG4-Related Disease (IgG4-RD) with Unique Combined Generalized Skin Rashes and Biliary Tract Manifestation: A Comprehensive Immunological Analysis

IgG4-RD is a multisystem fibroinflammatory disease characterized by the infiltration of tissues by IgG4 plasma cells. Combined skin and biliary tract involvement in IgG4-RD has not been described. We present perhaps the most comprehensive analysis of lymphocyte subsets in the first case of IgG4-related generalized skin rash and first case of combined skin and biliary tract manifestations. A 55-year-old male presented with painful jaundice and generalized macular pigmented pruritic eruptions, and CT abdomen revealed biliary obstruction. Ampulla and skin biopsies were subjected to histology and immunostaining. Naïve, central memory (TCM), effector memory (TEM), terminally differentiated effector memory (TEMRA) subsets of CD4+ and CD8+ T cells, T follicular helper subsets, naïve, transitional, marginal zone (MZ), germinal center (GC), IgM memory, and class-switched memory (CSM) B cells, and T follicular regulatory, regulatory B cells, CD4 Treg, and CD8 Treg were analyzed. Serum IgG4 was elevated at 448 mg/dL. Ampula biopsy showed lamina propria fibrosis and increased IgG4-positive plasma cells. Skin punch biopsy showed lymphoplasmacytic infiltrates with a 67% ratio of IgG4+:IgG+ plasma cells. CD4+TN and CD4+TCM decreased, whereas CD4+TEM increased. Naïve B cells increased; transitional, MZ, CSM, GC B cells, and plasmablasts decreased compared to control. CD4 Treg increased, whereas CD8 Treg and Breg decreased. In conclusion, IgG-RD may present with combined biliary tract and generalized dermatological manifestations. Changes in regulatory lymphocytes suggest their role in the pathogenesis of IgG4-RD.

Impact of genetic and environmental factors on autoimmune hepatitis

Autoimmune hepatitis (AIH) is a chronic non-resolving liver disease characterized by diffuse hypergammaglobulinemia, the presence of autoantibodies and characteristic histological findings. The disease can have catastrophic outcome with the development of end-stage liver disease if misdiagnosed/undiagnosed and left untreated. AIH pathogenesis remains obscure and the main hypothesis supports its development in genetically predisposed individuals after being exposed to certain environmental triggers. Genetic predisposition is linked to the presence of certain HLA alleles, mainly HLA-DR3 and HLA-DR4. However, a wide number of non-HLA epitopes have also been associated with the disease although data vary significantly among different ethnic groups. Therefore, it is likely that epigenetic alterations may also play a crucial role in disease's pathogenesis, although not yet extensively studied. The aim of this review was to summarize the genetic and environmental factors that have been associated with AIH, but also to open new insights towards the role of epigenetic modifications in the etiology of the disease.

Genetic risk factors for autoimmune hepatitis: implications for phenotypic heterogeneity and biomarkers for drug response

Autoimmune hepatitis (AIH) is a rare chronic progressive liver disease with autoimmune features. It mainly affects middle-aged women. AIH is occasionally complicated with liver cirrhosis that worsens the prognosis. Genetic and environmental factors are involved in the pathogenesis of AIH. Genetic studies of other diseases have been revealing of pathogenesis and drug efficacy. In this review, we summarize the genetic risk factors for AIH, including human leukocyte antigen (HLA) and non-HLA genes. A genome-wide association study (GWAS) on European AIH revealed the strongest associations to be with single nucleotide variants (SNVs) in HLA. Predisposing alleles for AIH were DRB1*03:01 and DRB1*04:01 in Europeans; DRB1*04:04, DRB1*04:05, and DRB1*13:01 in Latin Americans; and DRB1*04:01 and DRB1*04:05 in Japanese. Other risk SNVs in non-HLA genes for AIH were found by a candidate gene approach, but several SNVs were confirmed in replication studies. Some genetic factors of AIH overlapped with those of other autoimmune diseases. Larger-scale GWASs of other ethnic groups are required. The results of genetic studies might provide an explanation for the phenotypic heterogeneity of AIH and biomarkers for drug responses.

Immune inhibitory proteins and their pathogenic and therapeutic implications in autoimmunity and autoimmune hepatitis

Key inhibitory proteins can blunt immune responses to self-antigens, and deficiencies in this repertoire may promote autoimmunity. The goals of this review are to describe the key immune inhibitory proteins, indicate their possible impact on the development of autoimmune disease, especially autoimmune hepatitis, and encourage studies to clarify their pathogenic role and candidacy as therapeutic targets. English abstracts were identified in PubMed by multiple search terms. Full length articles were selected for review, and secondary and tertiary bibliographies were developed. Cytotoxic T lymphocyte antigen-4 impairs ligation of CD28 to B7 ligands on antigen presenting cells and inhibits the adaptive immune response by increasing anti-inflammatory cytokines, generating regulatory T cells, and reducing T cell activation and proliferation. Programed cell death antigen-1 inhibits T cell selection, activation, and proliferation by binding with two ligands at different phases and locations of the immune response. A soluble alternatively spliced variant of this protein can dampen the inhibitory signal. Autoimmune hepatitis has been associated with polymorphisms of the cytotoxic T lymphocyte antigen-4 gene, reduced hepatic expression of a ligand of programed cell death antigen-1, an interfering soluble variant of this key inhibitory protein, and antibodies against it. Findings have been associated with laboratory indices of liver injury and suboptimal treatment response. Abatacept, belatacept, CD28 blockade, and induction of T cell exhaustion are management considerations that require scrutiny. In conclusion, deficiencies in key immune inhibitory proteins may promote the occurrence of autoimmune diseases, such as autoimmune hepatitis, and emerging interventions may overcome these deficiencies. Investigations should define the nature, impact and management of these inhibitory disturbances in autoimmune hepatitis.

Clinical features of autoimmune hepatitis with acute presentation: a Japanese nationwide survey

BACKGROUND

Autoimmune hepatitis (AIH) is characterized by progressive inflammation and necrosis of hepatocytes and eventually leads to a variety of phenotypes, including acute liver dysfunction, chronic progressive liver disease, and fulminant hepatic failure. Although the precise mechanisms of AIH are unknown, environmental factors may trigger disease onset in genetically predisposed individuals. Patients with the recently established entity of AIH with acute presentation often display atypical clinical features that mimic those of acute hepatitis forms even though AIH is categorized as a chronic liver disease. The aim of this study was to identify the precise clinical features of AIH with acute presentation.

METHODS

Eighty-six AIH patients with acute presentation were retrospectively enrolled from facilities across Japan and analyzed for clinical features, histopathological findings, and disease outcomes.

RESULTS

Seventy-five patients were female and 11 were male. Patient age ranged from adolescent to over 80 years old, with a median age of 55 years. Median alanine transaminase (ALT) was 776 U/L and median immunoglobulin G (IgG) was 1671 mg/dL. There were no significant differences between genders in terms of ALT (P = 0.27) or IgG (P = 0.51). The number of patients without and with histopathological fibrosis was 29 and 57, respectively. The patients with fibrosis were significantly older than those without (P = 0.015), but no other differences in clinical or histopathological findings were observed. Moreover, antinuclear antibody (ANA)-positive (defined as × 40, N = 63) and -negative (N = 23) patients showed no significant differences in clinical or histopathological findings or disease outcomes. Twenty-five patients experienced disease relapse and two patients died during the study period. ALP ≥ 500 U/L [odds ratio (OR) 3.20; 95% confidence interval (CI) 1.12-9.10; P < 0.030] and GGT ≥ 200 U/L (OR 2.98; 95% CI 1.01-8.77; P = 0.047) were identified as independent risk factors of disease relapse.

CONCLUSIONS

AIH with acute presentation is a newly recognized disease entity for which diagnostic hallmarks, such as ALT, fibrosis, and ANA, are needed. Further investigation is also required on the mechanisms of this disorder. Clinicians should be mindful of disease relapse during patient care.

Association of a single nucleotide polymorphism upstream of ICOS with Japanese autoimmune hepatitis type 1

Autoimmune hepatitis (AIH) is an uncommon chronic autoimmune liver disease. Several studies reported the association of polymorphisms between CD28, CTLA4 and ICOS gene cluster in 2q33.2 with autoimmune or inflammatory diseases. The previous genome-wide association study on type 1 AIH in a European population has reported a risk G allele of a single nucleotide polymorphism (SNP), rs4325730, in this region. Here, we conducted an association study of this SNP with type 1 AIH in a Japanese population, as a replication study.An association study of rs4325730 was conducted in 343 Japanese AIH patients and 315 controls.We found that rs4325730 is associated with AIH (P=0.0173, odds ratio (OR) 1.30, 95% confidence interval (CI) 1.05-1.62, under the allele model for G allele, P=0.0070, OR 1.62, 95% CI 1.14-2.31, under the dominant model for G allele). This SNP was strongly associated with definite AIH (P=0.0134, OR 1.36, 95% CI 1.07-1.74; under allele model for G, P=0.0035, OR 1.85, 95% CI 1.22-2.81, under dominant model for G).This is the first replication association study of rs4325730 upstream of ICOS with AIH in the Japanese population and rs4325730G is a risk allele.

Genetic Association of PTPN22 Polymorphisms with Autoimmune Hepatitis and Primary Biliary Cholangitis in Japan

Autoimmune hepatitis (AIH) and primary biliary cholangitis (PBC) are liver-specific autoimmune conditions that are characterized by chronic hepatic damage and often lead to cirrhosis and hepatic failure. Specifically, the protein tyrosine phosphatase N22 (PTPN22) gene encodes the lymphoid protein tyrosine phosphatase, which acts as a negative regulator of T-cell receptor signaling. A missense single nucleotide polymorphism (SNP) (rs2476601) in PTPN22 has been linked to numerous autoimmune diseases in Caucasians. In the present series, nine SNPs in the PTPN22 gene were analyzed in 166 patients with AIH, 262 patients with PBC, and 322 healthy controls in the Japanese population using TaqMan assays. Although the functional rs3996649 and rs2476601 were non-polymorphic in all subject groups, the frequencies of the minor alleles at rs1217412, rs1217388, rs1217407, and rs2488458 were significantly decreased in AIH patients as compared with controls (all Pc < 0.05). There were no significant relationships with PTPN22 SNPs in PBC patients. Interestingly, the AAGTCCC haplotype was significantly associated with resistance to both AIH (odds ratio [OR] = 0.58, P = 0.0067) and PBC (OR = 0.58, P = 0.0048). SNPs in the PTPN22 gene may therefore play key roles in the genetic resistance to autoimmune liver disease in the Japanese.

Transitioning from Idiopathic to Explainable Autoimmune Hepatitis

Autoimmune hepatitis lacks an identifiable cause, and its diagnosis requires the exclusion of etiologically defined diseases that resemble it. Insights into its pathogenesis are moving autoimmune hepatitis from an idiopathic to explainable disease, and the goal of this review is to describe the insights that are hastening this transition. Two types of autoimmune hepatitis are justified by serological markers, but they also have distinctive genetic associations (DRB1 and DQB1 genes) and autoantigens. DRB1 alleles are the principal susceptibility factors in white adults, and a six amino acid sequence encoded in the antigen-binding groove of class II molecules of the major histocompatibility complex can influence the selection of autoantigens. Polymorphisms, including variants of SH2B3 and CARD10 genes, may affect immune reactivity and disease severity. The cytochrome mono-oxygenase, CYP2D6, is the autoantigen associated with type 2 autoimmune hepatitis, and it shares homologies with multiple viruses that might promote self-intolerance by molecular mimicry. Chemokines, especially CXCL9 and CXCL10, orchestrate the migration of effector cells to sites of injury and are associated with disease severity. Cells of the innate and adaptive immune responses promote tissue damage, and possible deficiencies in the number and function of regulatory T cells may facilitate the injurious process. Receptor-mediated apoptosis is the principal mechanism of hepatocyte loss, and cell-mediated and antibody-dependent mechanisms of cytotoxicity also contribute. Insights that explain autoimmune hepatitis will allow triggering exogenous antigens to be characterized, risk management to be improved, prognostic indices to be refined, and site-specific therapeutic interventions to emerge.

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.

Review article: permanent drug withdrawal is desirable and achievable for autoimmune hepatitis

BACKGROUND

Autoimmune hepatitis can be rendered treatment-free, but the difficulty, frequency and risks associated with the pursuit of this outcome are unclear.

AIM

To describe the frequency that autoimmune hepatitis can be rendered treatment-free, identify the features that characterise these patients, examine the pathogenic pathways that may sustain or terminate the disease and indicate management protocols that can obtain this result.

METHODS

Studies cited in Pub Med from 1972-2014 for autoimmune hepatitis, treatment, relapse, remission and outcome were selected.

RESULTS

The frequency of a treatment-free state varies from 19% to 40% in patients observed for ≥3 years after drug withdrawal. Complete laboratory resolution and reversion to normal liver tissue prior to drug withdrawal favours this response. The development of cirrhosis during therapy may increase treatment-dependence. Persistent liver damage and the generation of neo-antigens during the apoptosis of hepatocytes may perpetuate the disease. Genetic and age-related effects on the vigour of the immune response may also contribute. Reversion to normal liver tissue is achieved in only 22% of patients during conventional corticosteroid therapy, and the emerging pharmacological and biological interventions may improve this frequency. A management strategy designed to achieve a treatment-free state accommodates all candidates for this outcome, and it can be modified to a long-term maintenance strategy as warranted by the clinical response.

CONCLUSIONS

Permanent drug withdrawal is a treatment outcome that is desirable and achievable in patients with autoimmune hepatitis. Normalisation of liver tests and liver tissue during treatment enhances this occurrence.

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.

Autoimmune hepatitis in childhood: The role of genetic and immune factors

Autoimmune hepatitis (AIH) is a rare chronic inflammatory disease of the liver, which affects a group of patients who lost their immunological tolerance to antigens of the liver. It is clinically characterized by hypergammaglobulinemia, elevated liver enzymes, presence of autoantibodies and histological changes. Although being rare in children, it represents a serious cause of chronic hepatic disease that can lead to cirrhosis and hepatic failure. Clinical findings, exclusion of more common liver disorders and the detection of antibodies antinuclear antibodies, smooth muscle antibodies and anti-LKM1 are usually enough for diagnosis on clinical practice. The pathogenic mechanisms that lead to AIH remain obscure, but some research findings suggest the participation of immunologic and genetic factors. It is not yet knew the triggering factor or factors that stimulate inflammatory response. Several mechanisms proposed partially explain the immunologic findings of AIH. The knowledge of immune factors evolved might result in better markers of prognosis and response to treatment. In this review, we aim to evaluate the findings of research about genetic and immune markers and their perspectives of application in clinical practice especially in pediatric population.

Autoimmune hepatitis in diverse ethnic populations and geographical regions

Autoimmune hepatitis has diverse clinical phenotypes and outcomes in ethnic groups within a country and between countries, and these differences may reflect genetic predispositions, indigenous etiological agents, pharmacogenomic mechanisms and socioeconomic reasons. In the USA, African-American patients have cirrhosis more commonly, treatment failure more frequently and higher mortality than white American patients. Survival is poorest in Asian-American patients. Autoimmune hepatitis in other countries is frequently associated with genetic predispositions that may favor susceptibility to indigenous etiological agents. Cholestatic features influence treatment response; acute-on-chronic liver disease increases mortality and socioeconomic and cultural factors affect prognosis. Ethnic-based deviations from classical phenotypes and the frequency of late-stage disease can complicate the diagnosis and management of autoimmune hepatitis in non-white populations.

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.

Cytokine profiles affecting the pathogenesis of autoimmune hepatitis in Japanese patients

AIM

  Autoimmune hepatitis (AIH) is a chronic hepatitis of unknown etiology, although several cytokines have been implicated in its pathogenesis and severity. This study investigated the relationship between circulating cytokines in the pretreatment phase and remission following corticosteroid therapy phase in Japanese AIH patients.

METHODS

  A total of 28 cytokines were measured simultaneously by multiple bead array technology in the sera of 40 patients with AIH collected during pretreatment and remission phases.

RESULTS

  Interleukin (IL)-12p40, interferon-γ-inducible protein (IP-10), macrophage inflammatory protein (MIP)-1α, MIP-1β, IL-17F and IL-18 were significantly decreased during remission from pretreatment stage levels. The level of IP-10 in the pretreatment phase was correlated with serum levels of alanine aminotransferase.

CONCLUSION

  Our results suggest that a complex interplay of several cytokines, especially pro-inflammatory and T-helper 17 cytokines and regulatory T-cell suppression by IL-12p40 may play a pivotal role in the pathogenesis of AIH.

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

AIM

  Recently, the associations of +49A/G polymorphisms of cytotoxic T-lymphocyte antigen 4 (CTLA-4) gene with the susceptibility to type 1 autoimmune hepatitis (AIH) and primary biliary cirrhosis (PBC) have been reported; however these associations are yet to be fully elucidated. This study aimed to identify the associations of CTLA-4 gene +49A/G polymorphisms with the susceptibility to type 1 AIH and PBC by using a meta-analysis.

METHODS

  PubMed was searched by using the following keywords: "autoimmune hepatitis AND (polymorphism OR polymorphisms)" or "primary biliary cirrhosis AND (polymorphism OR polymorphisms)". Meta-analyses of five studies including 526 patients with type 1 AIH and 631 controls and seven studies including 1500 patients with PBC and 2345 controls were performed.

RESULTS

  For type 1 AIH, the odds ratio (OR) of G allele was 1.26 [95% confidence interval (CI) 1.06-1.51] although G/G homozygosity was not associated with the susceptibility to type 1 AIH. On the other hand, the OR of A/A homozygosity for type 1 AIH was 0.66 (95% CI 0.50-0.86). For PBC, the OR of G allele was 1.20 (95% CI 1.06-1.34). Furthermore, G/G homozygosity was significantly associated with the susceptibility to PBC (OR 1.29, 95% CI 1.01-1.66). The OR of A/A homozygosity for PBC was 0.81 (95% CI 0.70-0.94).

CONCLUSIONS

  This study suggests that CTLA-4 gene +49A/G polymorphisms may be associated with the susceptibility to type 1 AIH and PBC. Especially, while G/G genotype may be associated with the susceptibility to PBC, A/A genotype may be protective against type 1 AIH and PBC.

Genetic background of autoimmune hepatitis in Japan

Autoimmune hepatitis (AIH) is an organ-specific autoimmune disease characterized by chronic inflammation of the liver. Several studies from ethnically different countries have clarified that the genetic predisposition to type 1 AIH is linked mainly to human leukocyte antigen (HLA)-class II genes. Recently, molecular analysis using polymerase chain reaction (PCR)-based DNA typing has revealed that susceptibility to type 1 AIH is primarily associated with the HLA class II DRB1 locus, which encodes a polymorphic β chain of the HLA-DR antigen. However, additional susceptibility genes (either HLA or non-HLA) and/or environmental factors may also contribute to the development of type 1 AIH; in Japanese type 1 AIH patients, although the most influential gene in disease susceptibility is HLA-DRB1*04:05, several other genes have been identified as being involved in AIH pathogenesis or resistance and are the currently the focus of single nucleotide polymorphism analysis.

Clinical significance of immunoglobulin G4-associated autoimmune hepatitis

BACKGROUND

Immunoglobulin (Ig) G4-associated autoimmune hepatitis (AIH) is a recently identified and possibly new disease entity. However, the epidemiology and clinical features of IgG4-associated AIH remain uncertain. The aim of this study was to determine the prevalence and the clinical, serological, and histological characteristics of IgG4-associated AIH.

METHODS

We examined the clinical features, serum IgG4 concentration, liver biopsy histology, and IgG4-bearing plasma cell infiltration of 60 patients with type 1 AIH and 22 patients with autoimmune pancreatitis.

RESULTS

High serum IgG4 concentration (≥ 135 mg/dL) and IgG4-bearing plasma cell infiltration in the liver (≥ 10/high-power fields [HPFs]) were found in 2 of the 60 (3.3%) patients with type 1 AIH. These patients had high serum levels of IgE, giant cell change, and rosette formation in the liver. Although corticosteroid therapy reduced the serum IgG4 concentration and normalized liver enzymes and histology, one patient developed IgG4-related sclerosing cholangitis after 5 years of follow-up.

CONCLUSIONS

Because IgG4-associated AIH was found in over 3% of Japanese patients with type 1 AIH in our cohort, further studies are needed on this possible new disease entity and its impact on the diagnostic guidelines of AIH.

Association of TBX21 promoter polymorphisms with type 1 autoimmune hepatitis in a Chinese population

The T-box transcription factor T-bet is a key regulator for the lineage commitment in CD4 Th1 cells and CD8 T cells by activating the hallmark production of interferon-γ, and its expression level is linked to autoimmune diseases. T-1993C and T-1514C polymorphisms in the TBX21 gene (encoding T-bet) promoter can affect transcription activity. We investigated the distributions of these functional polymorphisms in 84 adult patients with type 1 autoimmune hepatitis (AIH-1) and 318 healthy controls. Intracellular T-bet staining of polarized CD4 Th1 cells from healthy controls corresponding to T-1993C genotypes were analyzed by flow cytometry. The -1993C allele frequency was 3.0% in AIH-1 and 11.8% in controls (p = 0.000 25). Individuals carrying the -1993C allele had a decreased risk to AIH-1 compared with those without the -1993C allele (p = 0.0016, odds ratio [OR] = 0.22, 95% confidence interval = 0.09-0.56). No association was found between the T-1514C polymorphism and AIH-1. The onset age of AIH-1 was also accelerated among -1993TT homozygotic individuals (p = 0.013). The fractions of T-bet positive Th1 cells in the -1993TT homozygotes were 2.2-fold higher than those in -1993CC homozygotes (p = 0.002). Our results suggest that the T-1993C polymorphism in the TBX21 promoter influences susceptibility to AIH-1 in a Chinese population.

Association analysis of cytotoxic T-lymphocyte antigen 4 gene polymorphisms with primary biliary cirrhosis in Japanese patients

BACKGROUND & AIMS

Primary biliary cirrhosis (PBC) is an organ-specific autoimmune disease of still unidentified genetic etiology that is characterized by chronic inflammation of the liver. Since cytotoxic T-lymphocyte antigen 4 (CTLA4) polymorphisms have recently been linked with PBC susceptibility in studies on Caucasians, we investigated the genetic association between CTLA4 polymorphisms and PBC in a Japanese population.

METHODS

Five single nucleotide polymorphisms (SNPs) in the CTLA4 gene (rs733618, rs5742909, rs231775, rs3087243, and rs231725) were genotyped in 308 patients with PBC and 268 healthy controls using a TaqMan assay.

RESULTS

One CTLA4 gene SNP (rs231725) was significantly associated with susceptibility to anti-mitochondrial antibody (AMA)-positive PBC, but clinical significance disappeared after correction for multiple testing. Moreover, CTLA4 gene SNPs did not influence AMA development or disease progression to orthotopic liver transplantation in our Japanese cohort. In haplotype analyses, one haplotype [haplotype 1 (CGGA)] at rs5742909, rs231775, rs3087243, and rs231725, was significantly associated with susceptibility to both AMA-positive PBC and overall PBC.

CONCLUSIONS

This study showed that CTLA4 gene polymorphisms had a modest, but significant association with susceptibility to PBC in the Japanese population. The connection between genetic variants and the function of the CTLA4 gene remains to be addressed in future investigations.

Advances in the diagnosis, pathogenesis, and management of autoimmune hepatitis

Autoimmune hepatitis (AIH) is characterized by chronic inflammation of the liver, interface hepatitis (based on histologic examination), hypergammaglobulinemia, and production of autoantibodies. Many clinical and basic science studies have provided important insights into the pathogenesis and treatment of AIH. Transgenic mice that express human antigens and develop autoantibodies, liver-infiltrating CD4(+) T cells, liver inflammation, and fibrosis have been developed as models of AIH. AIH has been associated with autoantibodies against members of the cytochrome P450 superfamily of enzymes, transfer RNA selenocysteine synthase, formiminotransferase cyclodeaminase, and the uridine diphosphate glucuronosyltransferases, whereas alleles such as DRB1*0301 and DRB1*0401 are genetic risk factors in white North American and northern European populations. Deficiencies in the number and function of CD4(+)CD25(+) (regulatory) T cells disrupt immune homeostasis and might be corrected as a therapeutic strategy. Treatment can be improved by continuing corticosteroid therapy until normal liver test results and normal liver tissue are within normal limits, instituting ancillary therapies to prevent drug-related side effects, identifying problematic patients early, and providing long-term maintenance therapy after patients experience a first relapse. Calcineurin inhibitors and mycophenolate mofetil are potential salvage therapies, and reagents such as recombinant interleukin-10, abatacept, and CD3-specific antibodies are feasible as therapeutics. Liver transplantation is an effective salvage therapy, even in the elderly, and AIH must be considered in all patients with graft dysfunction after liver transplantation. Identification of the key defects in immune homeostasis and antigen targets will direct new therapies.

Autoimmune liver disease

PURPOSE OF REVIEW

To review studies that improve the diagnosis and treatment of autoimmune hepatitis and extend the understanding of its pathogenic mechanisms.

RECENT FINDINGS

A simplified diagnostic scoring system has high sensitivity and specificity. Biliary changes detected by MRI are of uncertain nature and significance. New candidate autoantigens have been identified by proteomic analyses. T regulatory cells suppress disease activity; their adoptive transfer is beneficial in animal models. Budesonide in combination with azathioprine is effective frontline therapy. Bone marrow-derived mesenchymal stem cell transplantation may emerge as salvage therapy. Screening for hepatocellular cancer is justified. Racial disparities in disease severity, mortality, and treatment remain unexplained.

SUMMARY

Diagnosis has been simplified and management strategies have been upgraded. Biliary changes have been recognized but are of uncertain nature and significance. New antigens and antibodies have been described. T-cell populations that modulate disease activity have been characterized, and adoptive transfer of T regulatory cells is possible. Budesonide in combination with azathioprine is effective frontline therapy, and therapeutic interventions that target critical pathogenic mechanisms are feasible.

Nonneoplastic mimickers of pancreatic neoplasms

CONTEXT

A variety of nonneoplastic conditions may form pancreatic masses that mimic carcinoma. Approximately 5% to 10% of pancreatectomies performed with the clinical diagnosis of pancreatic cancer prove on microscopic evaluation to be pseudotumors.

OBJECTIVES

To illustrate the clinical and pathologic characteristics of the 2 most frequent pseudotumoral inflammatory conditions, autoimmune pancreatitis and paraduodenal pancreatitis, and describe the criteria that may be useful in the differential diagnosis versus pancreatic carcinoma.

DATA SOURCES

Recent literature and the authors' experience with the clinical and pathologic characteristics of autoimmune pancreatitis and paraduodenal pancreatitis.

CONCLUSIONS

The knowledge of the clinical, radiologic, and pathologic findings in both autoimmune pancreatitis and paraduodenal pancreatitis is crucial in making the correct preoperative diagnosis. Autoimmune pancreatitis, which occurs in isolated or syndromic forms, is characterized by a distinctive fibroinflammatory process that can either be limited to the pancreas or extend to the biliary tree. Its correct preoperative identification on biopsy material with ancillary immunohistochemical detection of dense immunoglobulin G4-positive plasma cell infiltration is possible and crucial to prevent major surgery and to treat these patients with steroid therapy. Paraduodenal pancreatitis is a special form of chronic pancreatitis that affects young males with a history of alcohol abuse and predominantly involves the duodenal wall in the region of the minor papilla. Pathogenetically, the anatomical and/or functional obstruction of the papilla minor, resulting from an incomplete involution of the intraduodenal dorsal pancreas, associated with alcohol abuse represents the key factor. Endoscopic drainage of the papilla minor, with decompression of the intraduodenal and dorsal pancreas, might be considered in these patients.