Autoimmune liver disease serology in acute hepatitis E virus infection

The etiology of autoimmune hepatitis (AIH) is unknown, though hepatotropic viruses may be potential triggers. Hepatitis E virus (HEV) infection, an increasingly recognized cause of acute hepatitis, has been misdiagnosed as AIH due to the occurrence of autoantibodies during its acute phase. It has also been suggested that HEV infection may lead to or unmask AIH. The HEV seroprevalence has been ascertained in patients with AIH, but the prevalence of AIH-related autoantibodies in patients with HEV infection has not been systematically tested. We aimed to investigate whether acute HEV infection is associated with the presence of AIH-relevant autoantibodies, following the liver autoimmune serology guidelines of the International AIH Group. We tested 48 patients with acute HEV infection. Half of them had at least one autoantibody, 17% two autoantibodies. Anti-nuclear antibody (ANA) were detected in 16 (33%), anti-smooth muscle antibody (SMA) in 10 (21%), and anti-neutrophil cytoplasmic antibody (ANCA) in 7 (14.6%). Of note, two patients showed SMA with VG or VGT patterns and five had ANA with homogeneous appearance, both being typical of AIH type 1. Other AIH-specific autoantibodies were negative. Atypical anti-mitochondrial antibody, without evidence of primary biliary cholangitis, was positive in one patient, disappearing at follow-up. Follow-up (median 12 months) serum was available from seven autoantibody positive patients: two became negative, while five remained positive, although no patient developed AIH to date. In conclusion, autoantibodies are frequently present during acute HEV infection, indicating that HEV should always be excluded before diagnosing AIH. Importantly, a minority of patients with acute hepatitis E develops AIH-specific autoantibodies, and, though they did not progress to autoimmune liver disease in the short-term, they warrant long-term monitoring.

Autoimmune hepatitis

Autoimmune hepatitis (AIH) is a severe liver disease that affects children and adults worldwide. The diagnosis of AIH relies on increased serum transaminase and immunoglobulin G levels, presence of autoantibodies and interface hepatitis on liver histology. AIH arises in genetically predisposed individuals when a trigger, such as exposure to a virus, leads to a T cell-mediated autoimmune response directed against liver autoantigens; this immune response is permitted by inadequate regulatory immune control leading to a loss of tolerance. AIH responds favourably to immunosuppressive treatment, which should be started as soon as the diagnosis is made. Standard regimens include fairly high initial doses of corticosteroids (prednisone or prednisolone), which are tapered gradually as azathioprine is introduced. For those patients who do not respond to standard treatment, second-line drugs should be considered, including mycophenolate mofetil, calcineurin inhibitors, mechanistic target of rapamycin (mTOR) inhibitors and biologic agents, which should be administered only in specialized hepatology centres. Liver transplantation is a life-saving option for those who progress to end-stage liver disease, although AIH can recur or develop de novo after transplantation. In-depth investigation of immune pathways and analysis of changes to the intestinal microbiota should advance our knowledge of the pathogenesis of AIH and lead to novel, tailored and better tolerated therapies.

Outcomes of surgical management of familial intrahepatic cholestasis 1 and bile salt export protein deficiencies

Progressive familial intrahepatic cholestasis (PFIC) with normal circulating gamma‐glutamyl transpeptidase levels can result from mutations in the ATP8B1 gene (encoding familial intrahepatic cholestasis 1 [FIC1] deficiency) or the ABCB11 gene (bile salt export protein [BSEP] deficiency). We investigated the outcomes of partial external biliary diversion, ileal exclusion, and liver transplantation in these two conditions. We conducted a retrospective multicenter study of 42 patients with FIC1 deficiency (FIC1 patients) and 60 patients with BSEP deficiency (BSEP patients) who had undergone one or more surgical procedures (57 diversions, 6 exclusions, and 57 transplants). For surgeries performed prior to transplantation, BSEP patients were divided into two groups, BSEP‐common (bearing common missense mutations D482G or E297G, with likely residual function) and BSEP‐other. We evaluated clinical and biochemical outcomes in these patients. Overall, diversion improved biochemical parameters, pruritus, and growth, with substantial variation in individual response. BSEP‐common or FIC1 patients survived longer after diversion without developing cirrhosis, being listed for or undergoing liver transplantation, or dying, compared to BSEP‐other patients. Transplantation resolved cholestasis in all groups. However, FIC1 patients commonly developed hepatic steatosis, diarrhea, and/or pancreatic disease after transplant accompanied by biochemical abnormalities and often had continued poor growth. In BSEP patients with impaired growth, this generally improved after transplantation. Conclusion: Diversion can improve clinical and biochemical status in FIC1 and BSEP deficiencies, but outcomes differ depending on genetic etiology. For many patients, particularly BSEP‐other, diversion is not a permanent solution and transplantation is required. Although transplantation resolves cholestasis in patients with FIC1 and BSEP deficiencies, the overall outcome remains unsatisfactory in many FIC1 patients; this is mainly due to extrahepatic manifestations. (Hepatology Communications 2018;2:515‐528)

Real-world management of juvenile autoimmune liver disease

Background and aims

Juvenile autoimmune liver disease (JAILD) includes paediatric forms of autoimmune hepatitis (AIH) and autoimmune sclerosing cholangitis (ASC). Since evidence is scarce, there are currently no evidence-based management guidelines for juvenile AIH. This survey was carried out amongst the paediatric members of the International AIH Group (IAIHG) to describe their practices in the management of JAILD.

Methods

An online survey questionnaire was distributed to members of the IAIHG with active practice (https://www.surveymonkey.de/r/Juvenile_AILD). The questionnaire consisted of four clinical scenarios on different presentations of AIH.

Results

Fifty-eight surveys were sent to the IAIHG members, out of which 43 (74%, 22 countries, four continents) were returned. None reported budesonide as a first-line induction agent for the acute presentation of AIH. Sixteen (37%) routinely perform liver biopsy at three years of biochemical remission. Thirty-five respondents (81%) perform magnetic resonance cholangiography (MRC) at presentation. Ciclosporin is the most widely used second-line agent (number of patients treated = ∼360, 21 centres). Mycophenolate mofetil (n = ∼225, 31 centres), tacrolimus (n = ∼130, 21 centres) and sirolimus (n = ∼5, 3 centres) are less often reported. Rescue therapy with infliximab and rituximab has been tried in eight centres (n = ∼19) and nine centres (n = ∼16), respectively.

Conclusions

Prednisolone remains the preferred first-line induction agent in JAILD. MRC at presentation is performed by the large majority of participants. Participants reported a wide variation in performing liver biopsy for therapy evaluation during follow-up. Within the paediatric members of the IAIHG there is considerable experience with second-line therapeutic agents.

Diagnosis and Management of Pediatric Autoimmune Liver Disease: ESPGHAN Hepatology Committee Position Statement

Paediatric autoimmune liver disease is characterized by inflammatory liver histology, circulating autoantibodies, and increased levels of IgG, in the absence of a known etiology. Three conditions have a likely autoimmune pathogenesis: autoimmune hepatitis (AIH), autoimmune sclerosing cholangitis, and de novo AIH after liver transplantation. Two types of pediatric AIH are recognized according to seropositivity for smooth muscle and/or antinuclear antibody (AIH-1) or liver kidney microsomal type 1 and/or anti-liver cytosol type 1 antibodies (AIH-2).Pertinent issues addressing the diagnosis, treatment, and long-term follow-up were formulated by a core group of ESPGHAN members. They have commissioned the first authors with execution of this project. Initially, they have performed a systematic literature search on MEDLINE, ResearchGate, and Mendeley databases during the last 30 years and produced a document focusing on prospective and retrospective studies in children. The ESPGHAN core group and ESPGHAN Hepatology Committee members voted on each recommendation, using a formal voting technique.

Serology in autoimmune hepatitis: A clinical-practice approach

Serology is key to the diagnosis of autoimmune hepatitis (AIH). Clinicians need to be aware of which tests to request, how to interpret the laboratory reports, and be familiar with the laboratory methodology. If correctly tested, >95% of AIH patients show some serological reactivity. Indirect immunofluorescence on triple rodent tissue is recommended as first screening step, since it allows the detection of all liver-relevant autoantibodies, except for anti-soluble liver antigen (SLA) antibody, which needs to be detected by molecular based assays. The threshold of immunofluorescence positivity is a titer equal or exceeding 1/40, but for patients younger than 18years even lower titers are clinically significant. Anti-nuclear antibody (ANA) and/or anti-smooth muscle (SMA) antibody characterize type 1 AIH. ANA in AIH typically shows a homogeneous staining pattern on HEp2 cells, without any specific target antigen. Anti-SMA displays different staining patterns on indirect immunofluorescence: the vascular/glomerular (VG) and the vascular/glomerular/tubular (VGT) patterns are considered specific for AIH, whilst the V pattern can be found in a variety of diseases. Type 2 AIH, which is rare and affects mostly children/adolescents, is characterized by anti-liver kidney microsomal 1 and/or anti-liver cytosol 1 antibodies. The presence of anti-neutrophil cytoplasmic antibody (ANCA), particularly atypical p-ANCA (pANNA), points to the diagnosis of AIH, especially in absence of other autoantibodies. Since it is associated with sclerosing cholangitis and inflammatory bowel disease, these conditions have to be ruled out. The only antibody specific for AIH is anti-SLA, which is associated with a more severe disease course.

Anti-TNFα Treatment in Children and Adolescents With Combined Inflammatory Bowel Disease and Autoimmune Liver Disease

OBJECTIVES

Inflammatory bowel disease (IBD) and autoimmune liver disease (AILD) are closely associated, the former often dictating progression of the latter. Antibodies to tumor necrosis factor alpha (anti-TNFα) are effective in the management of IBD, but may cause liver injury.

METHODS

Retrospective review of medical records of patients with juvenile AILD who received anti-TNFα for IBD to evaluate the safety and efficacy of anti-TNFα.

RESULTS

Eleven patients (6 boys), ages 9 to 15 years (median 13 years) were identified. Ten had ulcerative colitis and 1 Crohn disease; 2 had autoimmune hepatitis type 1 and 9 autoimmune hepatitis-sclerosing cholangitis variant. All patients were started on infliximab (IFX, 5 mg/kg) and 2 required dose increase (10 mg/kg); 3 of 11 switched to adalimumab due to allergic reaction or nonresponse. Three received adalimumab after losing response or developing antibodies to IFX. Liver function tests (LFTs) improved in 5, 1 continued to have stably abnormal LFTs and 2 maintained normal LFTs. Patients on adalimumab showed stable or improved liver function compared to pretreatment status. Six of 8 treated with a full course of IFX maintained clinical remission of IBD for 6 months to 2.5 years; of the 6 patients treated with adalimumab, 1 sustained IBD clinical remission for 24 months, 2 achieved remission only after tacrolimus addition and 3 did not respond.

CONCLUSIONS

IBD in patients with AILD can be aggressive, requiring escalation to anti-TNFα or switching to other biologics. In this series, anti-TNFα did not impair liver function and improved gut disease in most of the patients, indicating that it can be beneficial and safe.

Regulatory T-cell conditioning endows activated effector T cells with suppressor function in autoimmune hepatitis/autoimmune sclerosing cholangitis

Imbalance between T regulatory (Treg) and T effector (Teff) cells is likely to contribute to the induction and perpetuation of liver damage in autoimmune hepatitis (AIH) and autoimmune sclerosing cholangitis (AISC) either through inability of Tregs to restrain proliferation and effector cytokine production by responders or through conversion of Tregs into T helper type 1 (Th1) or type 17 (Th17) effector lymphocytes. We investigated the effect of Treg skewing on the phenotypic and functional properties of CD4⁺ CD127⁺ CD25^high cells, an activated subset of Teff, in 32 patients with AIH and 20 with AISC and in 36 healthy subjects. In AIH/AISC we noted a substantial increase in peripheral blood-derived CD4⁺ CD127⁺ CD25^high cells that display a Th1/Th17 phenotypic profile, as reflected by heightened interferon gamma and interleukin 17 (IL-17) production as well as by high levels of T-bet and related orphan receptor 3 expression, which is strongly correlated with disease activity. CD4⁺ CD127⁺ CD25^high cells are unresponsive to low-dose IL-2 and in patients have marked proliferative ability, further enhanced by stimulation with IL-7. CD4⁺ CD127⁺ CD25^high cells obtained from CD4⁺ cells exposed to Treg polarizing conditions display enhanced IL-10 production; up-regulate CD49b and LAG-3, markers of T regulatory 1 cells; and effectively suppress responder cell proliferation in both healthy subjects and AIH/AISC patients through a mechanism which is dependent on interferon gamma and IL-17. The suppressive function of CD4⁺ CD127⁺ CD25^high cells is maintained upon proinflammatory challenge in healthy subjects but not in AIH/AISC.

CONCLUSION

Treg skewing confers activated Teff phenotypic and functional properties of T regulatory 1 cells in health and in AIH/AISC, though suppressive function is lost in patients upon proinflammatory challenge; protracted modulation of the inflammatory environment is required to attenuate the effector potential while boosting immunoregulatory properties in Teff. (Hepatology 2017;66:1570-1584).

Autoimmune Liver Disease in Children with Sickle Cell Disease

OBJECTIVE

To assess the incidence, clinical features, and outcome of autoimmune liver disease (AILD) in patients with sickle cell disease (SCD).

STUDY DESIGN

Single center retrospective review of patients with SCD with AILD referred between 1999 and 2015.

RESULTS

Thirteen of 77 (17%) patients with SCD with hepatic dysfunction were diagnosed with AILD (median age 11, range, 3.4-16 years) with a female preponderance (77%). Acute hepatitis and insidious onset were the commonest presentations. Two patients (15%) presented with acute liver failure. In 2 patients (15%), parvovirus B19-induced transient red cell aplasia preceded the diagnosis of AILD. All patients were positive for antinuclear and/or smooth muscle autoantibodies. Six of 12 patients (50%) had cholangiopathy on cholangiogram suggesting autoimmune sclerosing cholangitis (ASC). Liver biopsy, performed in 11 patients without complications, showed interface hepatitis in 90%. Patients with AILD were treated with standard immunosuppression. After a median follow-up of 3.8 years (range, 0.2-14.3), 10 patients are alive (1 was transplanted 6.4 years after diagnosis); 2 are lost to follow-up; 1 died of subdural hemorrhage before starting treatment for AILD. Five (42%) achieved full and 4 (33%) partial biochemical remission. Ulcerative colitis, present in 4 patients (2 male patients, 3 with ASC) was diagnosed in 2 patients before and in 2 patients after the diagnosis of AILD.

CONCLUSIONS

AILD is not uncommon in patients with SCD, affecting mainly female patients and responding satisfactorily to immunosuppressive treatment. Liver biopsy is helpful in confirming the diagnosis and can be safely performed in the absence of acute vaso-occlusive sickling episodes. Ulcerative colitis is common in the presence of ASC.

Autoimmune hepatitis: Standard treatment and systematic review of alternative treatments

Autoimmune hepatitis is a rare chronic inflammatory liver disease, affecting all ages, characterised by elevated transaminase and immunoglobulin G levels, positive autoantibodies, interface hepatitis at liver histology and good response to immunosuppressive treatment. If untreated, it has a poor prognosis. The aim of this review is to summarize the evidence for standard treatment and to provide a systematic review on alternative treatments for adults and children. Standard treatment is based on steroids and azathioprine, and leads to disease remission in 80%-90% of patients. Alternative first line treatment has been attempted with budesonide or cyclosporine, but their superiority compared to standard treatment remains to be demonstrated. Second-line treatments are needed for patients not responding or intolerant to standard treatment. No randomized controlled trials have been performed for second-line options. Mycophenolate mofetil is the most widely used second-line drug, and has good efficacy particularly for patients intolerant to azathioprine, but has the major disadvantage of being teratogenic. Only few and heterogeneous data on cyclosporine, tacrolimus, everolimus and sirolimus are available. More recently, experience with the anti-tumour necrosis factor-alpha infliximab and the anti-CD20 rituximab has been published, with ambivalent results; these agents may have severe side-effects and their use should be restricted to specialized centres. Clinical trials with new therapeutic options are ongoing.

Autoimmunhepatitis: das Wichtigste für die Praxis

Zusammenfassung. Autoimmunhepatitis (AIH) ist eine chronisch entzündliche immunvermittelte Lebererkrankung. Sie kann alle Altersgruppen betreffen und ist durch hohe Transaminase- und Immunglobulin G (IgG)- Werte, positive Autoantikörper sowie histologisch durch Grenzzonenhepatitis gekennzeichnet. Wenn unbehandelt, führt sie zu Zirrhose und Leberversagen; wenn sie aber rechtzeitig diagnostiziert und behandelt wird, hat die Erkrankung eine ausgezeichnete, langfristige Prognose. Die Behandlung basiert auf Steroiden und Azathioprin. Dieser Artikel fasst die wichtigsten Punkte für die klinische Praxis zusammen.

Atovaquone/proguanil-induced autoimmune-like hepatitis

We report a novel association between the commonly used antimalarial medication atovaquone/proguanil and drug‐induced autoimmune‐like hepatitis. The patient developed severe liver disease fulfilling biochemical, immunologic, and histologic criteria for the diagnosis of autoimmune hepatitis after the inadvertent rechallenge with the offending drug, which had caused self‐limited hepatitic symptoms a year previously. Over a period of 18 months, the patient underwent two follow‐up liver biopsies showing progressive resolution of the liver inflammation and achieved complete biochemical and immunologic remission on steroids. This remission persisted for 20 months following treatment withdrawal. Conclusion: This well documented case raises awareness of the potential hepatotoxicity of atovaquone/proguanil. (Hepatology Communications 2017;1:293–298)

Immunosuppressive drugs affect interferon (IFN)-γ and programmed cell death 1 (PD-1) kinetics in patients with newly diagnosed autoimmune hepatitis

Autoimmune hepatitis (AIH) is characterized by overwhelming effector immune responses associated with defective regulatory T cells (T_regs ). Several lines of evidence indicate CD4 as the main effectors involved in autoimmune liver damage. Herein we investigate the in-vitro effects of prednisolone, 6-mercaptopurine, cyclosporin, tacrolimus, mycophenolic acid (MPA) and rapamycin, immunosuppressive drugs (ISDs) used in AIH treatment, on the expression of proinflammatory cytokines, co-inhibitory molecules and ability to proliferate of CD4⁺ CD25^- cells, isolated from the peripheral blood of treatment-naive patients with AIH. We note that in healthy subjects (HS) following polyclonal stimulation and in the absence of ISDs, the expression of interferon (IFN)-γ, interleukin (IL)-17 and tumour necrosis factor (TNF)-α by CD4 effectors peaks at 48 h and decreases at 96 h to reach baseline levels. In contrast, in AIH the expression of all these proinflammatory cytokines continue rising between 48 and 96 h. Levels of programmed cell death-1 (PD-1), T cell immunoglobulin and mucin domain-containing molecule-3 (TIM-3) and cytotoxic T lymphocyte antigen-4 (CTLA-4) increase over 96-h culture both in HS and AIH, although with faster kinetics in the latter. Exposure to ISDs contains IFN-γ and PD-1 expression in AIH, where control over CD4⁺ CD25^- cell proliferation is also noted upon exposure to MPA. Treatment with tacrolimus and cyclosporin render CD4⁺ CD25^- cells more susceptible to T_reg control. Collectively, our data indicate that in treatment-naive patients with AIH, all ISDs restrain T helper type 1 (Th1) cells and modulate PD-1 expression. Furthermore, they suggest that tacrolimus and cyclosporin may ameliorate effector cell responsiveness to T_regs .

Mutations in DCDC2 (doublecortin domain containing protein 2) in neonatal sclerosing cholangitis

BACKGROUND & AIMS

Neonatal sclerosing cholangitis (NSC) is a severe neonatal-onset cholangiopathy commonly leading to liver transplantation (LT) for end-stage liver disease in childhood. Liver biopsy findings histopathologically resemble those in biliary atresia (BA); however, in NSC extrahepatic bile ducts are patent, whilst in BA their lumina are obliterated. NSC is commonly seen in consanguineous kindreds, suggesting autosomal recessive inheritance.

METHODS

From 29 NSC patients (24 families) identified, DNA was available in 24 (21 families). Thirteen (7 male) patients (12 families) of consanguineous parentage were selected for whole exome sequencing. Sequence variants were filtered for homozygosity, pathogenicity, minor allele frequency, quality score, and encoded protein expression pattern.

RESULTS

Four of 13 patients were homozygous and two were compound heterozygous for mutations in the doublecortin domain containing 2 gene (DCDC2), which encodes DCDC2 protein and is expressed in cholangiocyte cilia. Another 11 patients were sequenced: one (with one sibling pair) was compound heterozygous for DCDC2 mutations. All mutations were protein-truncating. In available liver tissue from patients with DCDC2 mutations, immunostaining for human DCDC2 and the ciliary protein acetylated alpha-tubulin (ACALT) showed no expression (n=6) and transmission electron microscopy found that cholangiocytes lacked primary cilia (n=5). DCDC2 and ACALT were expressed in NSC patients without DCDC2 mutations (n=22). Of the patients carrying DCDC2 mutations, one died awaiting LT; five came to LT, of whom one died 2years later. The other 4 are well.

CONCLUSION

Among 24 NSC patients with available DNA, 7 had mutations in DCDC2 (6 of 19 families). NSC patients in substantial proportion harbour mutations in DCDC2. Their disease represents a novel liver-based ciliopathy.

LAY SUMMARY

Neonatal sclerosing cholangitis (NSC) is a rare genetic form of liver disease presenting in infancy. Through next generation sequencing we identified mutations in the gene encoding for doublecortin domain containing 2 (DCDC2) protein in a group of NSC children. DCDC2 is a signalling and structural protein found in primary cilia of cholangiocytes. Cholangiocytes are the cells forming the biliary system which is the draining system of the liver.

Contemporary issues and future directions in autoimmune hepatitis

Autoimmune hepatitis (AIH) is a severe life-threatening hepatopathy of unknown etiology, affecting both pediatric and adult populations, and characterised by inflammatory liver histology, circulating non-organ-specific autoantibodies, and hypergammaglobulinaemia. AIH is a very heterogeneous disease with a variety of clinical presentations, ranging from asymptomatic liver test abnormalities to acute severe hepatitis or even acute liver failure. It responds very well to immunosuppressive treatment with prednisolone with or without azathioprine. Patients who are intolerant or fail to respond to standard therapy are candidates for alternative immunosuppressive regimens, the combination of steroids with mycophenolate mofetil or calcineurin inhibitors being the most frequently reported. The pathogenesis of AIH remains not completely understood, although there is evidence that genetic predisposition, molecular mimicry and defective immunoregulatory mechanisms contribute to the autoimmune liver damage. Areas covered: A literature search was conducted using the key-words 'autoimmune hepatitis', 'immunogenetics', 'regulatory T-cells' and 'immunosuppression'. The aim of this review is to discuss recent breakthroughs in the understanding AIH pathogenesis, diagnosis and treatment. Expert commentary: Progress in the understanding of AIH pathogenesis is likely to contribute to the development of novel therapeutic strategies, such as the adoptive transfer of autologous expanded antigen-specific regulatory T-cells.

Recurrence of autoimmune liver disease and inflammatory bowel disease after pediatric liver transplantation

Approximately 10% of children with autoimmune hepatitis (AIH) and 30% of those with sclerosing cholangitis (SC) require liver transplantation (LT). LT is indicated in patients who present with fulminant hepatic failure (ie, with encephalopathy) and in those who develop end-stage liver disease despite treatment. After LT, recurrent AIH is reported in approximately 30% of patients and recurrent SC in up to 50%. Diagnosis of recurrence is based on biochemical abnormalities, seropositivity for autoantibodies, interface hepatitis on histology, steroid dependence, and, for SC, presence of cholangiopathy. Recurrence of SC after LT is often associated with poorly controlled inflammatory bowel disease (IBD). Recurrence may even appear years after LT; therefore, steroid-based immunosuppression should be maintained at a higher dose than that used for patients transplanted for nonautoimmune liver diseases. Although the impact of recurrent disease on graft function is controversial, it seems that in pediatric LT recipients recurrence of AIH or SC is associated with compromised graft survival. Exacerbation of preexistent IBD may be observed after LT for SC or AIH, and IBD appears to have a more aggressive course than before LT. In addition, IBD can develop de novo following LT. Liver Transplantation 22 1275-1283 2016 AASLD.

Cutting edge issues in autoimmune hepatitis

Autoimmune hepatitis (AIH) is a severe liver disease affecting all age groups worldwide. Novel basic and clinical aspects of AIH, addressed at a Monothematic Conference in London in September 2015, are highlighted in this review. The diagnosis of AIH relies upon detection of characteristic autoantibodies, hypergammaglobulinemia, and interface hepatitis on liver histology. The International Autoimmune Hepatitis Group (IAIHG) has devised diagnostic scoring systems to help in comparative studies and clinical practice. AIH arises in a genetically predisposed host, when yet unknown triggers - such an encounter with a pathogen - lead to a T cell-mediated immune response targeting liver autoantigens. This immune response is inadequately controlled because regulatory mechanisms are impaired. The mainstay of treatment for AIH is immunosuppression, which should be instituted as soon as the diagnosis is made. Standard treatment regimens include relatively high doses of predniso(lo)ne, which are tapered gradually as azathioprine is introduced. Recent guidelines have described newer treatment regimens and have tightened the goal of therapy to complete normalization of biochemical, serological and histological parameters. Mycophenolate mofetil, calcineurin inhibitors, mTOR inhibitors and biological agents are potential salvage therapies, but should be reserved for selected non-responsive patients and administered only in experienced centers. Liver transplantation is a life-saving option for those patients who progress to end-stage liver disease. Further dissection of cellular and molecular pathways involved in AIH pathogenesis is likely to lead to the discovery of novel, tailored and better tolerated therapies.

CD39 mediated regulation of Th17-cell effector function is impaired in juvenile autoimmune liver disease

BACKGROUND & AIMS

T-helper-type 17 (Th17) cells are involved in autoimmune tissue damage. CD39 is an ectonucleotidase that catalyzes extracellular ATP/ADP hydrolysis, culminating in the generation of immunosuppressive adenosine. Functional CD39 expression confers immunosuppressive properties upon immune cells. As the proportion of CD39 lymphocytes is decreased in juvenile autoimmune liver disease (AILD), we have explored whether decreased CD39 expression is present on Th17 cells and whether this phenomenon is associated with heightened effector function and inflammation.

METHODS

Thirty-eight patients with juvenile AILD (22 autoimmune hepatitis and 16 autoimmune sclerosing cholangitis), 8 disease controls (DC) and 16 healthy subjects (HS) were studied. Peripheral blood cell phenotype was determined by flow cytometry; ability to suppress by inhibition of cell proliferation/effector cytokine production; ectoenzymatic activity by thin layer chromatography; expression of adenosine receptor, adenosine deaminase (ADA) and phosphodiesterases (PDE) by quantitative real-time PCR or by Western Blot.

RESULTS

CD39(+) Th17 (Th17(CD39+)) cells from HS appear activated and contain high frequencies of lymphocytes producing regulatory cytokines. In AILD, however, Th17(CD39+) cells are markedly diminished and fail to generate AMP/adenosine, thereby limiting control of both target cell proliferation and IL-17 production. When compared to HS, Th17 cells from AILD patients also show lower A2A adenosine receptor expression while displaying similar levels of PDE4A, PDE4B and ADA. Only rare Th17(CD39+) cells are observed by liver immunohistochemistry.

CONCLUSIONS

Th17(CD39+) cells in juvenile AILD are both quantitatively decreased and qualitatively deficient. Low levels CD39 and A2A expression may contribute to the perpetuation of Th17 cell effector properties and unfettered inflammation in this disease.

Autoimmune hepatitis: From mechanisms to therapy

Autoimmune hepatitis (AIH) is a progressive inflammatory hepatopathy and an important cause of end-stage liver disease. Its aetiology remains unknown, though both genetic and environmental factors are involved in its development. The major mechanism of autoimmune liver damage involves immune reactions against host liver antigens. Numerical and functional defects of regulatory T-cells play a permissive role enabling autoimmune liver injury to occur and persist. The most typical features of AIH are female preponderance, hypergammaglobulinaemia, seropositivity for circulating autoantibodies and a picture of interface hepatitis on histology. Two types of AIH are distinguished according to serological profile: AIH type 1 patients are positive for anti-nuclear and/or anti-smooth muscle antibodies, whereas AIH type 2 patients are defined by the positivity for anti-liver kidney microsomal type 1 antibody and/or for anti-liver cytosol type 1 antibody. Clinical manifestations are variable, and AIH onset is often ill-defined, frequently mimicking acute hepatitis; its course may be fluctuating. AIH responds to immunosuppressive treatment in the majority of cases. Steroids with or without azathioprine should be instituted promptly upon diagnosis. Remission is achieved in some 80% of patients. For the remaining 20% of patients, alternative immunosuppressive agents such as mycophenolate mofetil and calcineurin inhibitors are an option. Liver transplantation should be considered for those patients who progress to cirrhosis and develop complications of end-stage liver disease, as well as for those presenting with acute liver failure; outcomes are excellent, although the disease may recur in the allograft.

Sclerosing Cholangitis in Children and Adolescents

Sclerosing cholangitis in pediatric age is a severe disease, often associated with inflammatory bowel disease. It recognizes different etiologies. Management and prognosis depend on the underlying cause. A high proportion of patients have autoimmune features similar to those of autoimmune hepatitis and respond biochemically to immunosuppression, although bile duct disease progresses in half of them leading to liver transplant. The disease can recur after transplant. Severity of liver disease and risk of recurrence after transplant are linked to the severity of bowel disease.