A study of molecular mimicry and immunological cross-reactivity between hepatitis B surface antigen and myelin mimics

On the basis of the reported association between hepatitis B vaccination (HBvacc) and autoimmune demyelinating complications such as multiple sclerosis (MS), we have looked for aminoacid similarities between the small hepatitis B virus surface antigen (SHBsAg), and the MS-autoantigens myelin basic protein (MBP) and myelin oligodendrocyte glycoprotein (MOG) that could serve as targets of immunological cross-reactivity. Twenty-mer peptides spanning 4 SHBsAg/MOG and 1 SHBsAg/MBP mimicking pairs, were constructed and tested by ELISA as targets of cross-reactive responses. A total of 147 samples from 58 adults were collected before HBvacc (58/58), and post-HBvacc (48/58 before the second and 41/58 before the third boost). Eighty-seven sera from anti-SHBsAg antibody negative patients with various diseases were tested as pathological controls. Reactivity to at least one of the SHBsAg peptides was found in 8 (14%) pre-HBvacc subjects; amongst the remaining 50, reactivity to at least one of the SHBsAg peptides appeared in 47 (94%) post-HBvacc. Reactivity to at least one of the MOG mimics was present in 4 (8%) pre-HBvacc and in 30 (60%) post-HBvacc (p < 0.001). Overall 30/50 (60%) vaccinees had SHBsAg/MOG double reactivity on at least one occasion compared to none before-vaccination and in 2 (2%) of the pathological controls (p < 0.001 for both). SHBsAg/MOG double reactivity was cross-reactive as confirmed by inhibition studies. At 6 months post-vaccination, 3 of the 4 anti-MOG reactive cases before vaccination and 7 of the 24 (29%) of the anti-MOG reactive cases at 3 months post-vaccination had lost their reactivity to MOG_5-24. There was no reactivity to the SHBsAg/MBP mimics. None of the vaccinees reported symptoms of demyelinating disorders. In view of the observed SHBsAg/MOG cross-reactivity, the vaccine's possible role as an immunomodulator of viral/self cross-reactivity must be further investigated.

Acute liver failure in neonates

Acute liver failure (ALF) in neonates is a rare but often fatal event. Though in adults and older children, a main symptom of ALF is hepatic encephalopathy, this is very difficult to diagnose and prove in infants. Causes of ALF in neonates encompass metabolic, infectious and haematological disorders, congenital vascular/heart abnormalities, and drugs. Infants with ALF should only be treated in specialised paediatric hepatology centres with facilities for liver transplantation, since for many liver transplant, with a long term survival of over 60%, is the only therapeutic option.

Interferon alfa-2b in combination with ribavirin for the treatment of chronic hepatitis C in children: efficacy, safety, and pharmacokinetics

Chronic hepatitis C virus (HCV) infection is usually asymptomatic in children, but significant liver disease may occur. We evaluated the efficacy, safety, and pharmacokinetics of interferon alfa-2b and ribavirin in children with chronic HCV. We determined the optimal ribavirin dose in an initial cohort of a phase 1 study and then subsequently used it, in combination with interferon alfa-2b, in a second cohort of this study and a phase 3 trial. The primary efficacy endpoint in all studies was sustained virological response, defined by undetectable serum HCV RNA 24 weeks after completion of therapy. All efficacy and safety analyses were performed on the intent-to-treat population. Children receiving interferon alfa-2b plus ribavirin 15 mg/kg/d in the phase 1 study had the maximum reduction in serum HCV RNA at treatment weeks 4 and 12 with an acceptable safety profile. This ribavirin dose was selected as optimal and used in all subsequent studies. In all, 46% (54/118) of optimally treated children achieved sustained virological response. Sustained virological response was significantly higher in children with HCV genotype 2/3 (84%) than in those with HCV genotype 1 (36%). Adverse events led to dose modification in 37 (31%) and discontinuation in 8 (7%). Multiple-dose interferon alfa-2b and ribavirin peak and trough concentrations and area-under-the-curve were similar between children and adults. In conclusion, interferon alfa-2b in combination with ribavirin is effective and safe in children with chronic hepatitis C virus.

Neonatal hemochromatosis--medical treatment vs. transplantation: the king's experience

The aim of our study was to compare the outcome of medical treatment vs. liver transplantation in infants with neonatal hemochromatosis (NH) referred to King's College Hospital from 1990-2002. We conducted a retrospective review of 19 children from 14 families. Fifteen children presented at birth and 4 during the first week of life. One child was diagnosed by cordocentesis at 30 weeks of gestation. NH recurred in 7 of 9 families with further children. In one family, 2 children from different fathers were affected. All patients had elevated ferritin levels, hypoalbuminemia, and coagulopathy. Liver histology showed parenchymal collapse, diffuse fibrosis, and moderate to severe hepatocyte hemosiderin deposition. Extrahepatic siderosis was demonstrated by magnetic resonance in 2 patients, lip biopsy in 3, and autopsy in 10. Ten patients received a chelation-antioxidant cocktail: 1 survived, 4 died, and 5 required liver transplantation, of whom 2 died. One of the 9 infants who did not receive the cocktail survived with medical support, 3 died, and 5 required transplantation, of whom 3 died. Seven children are alive, 5 after transplantation, at a median follow-up of 5.6 years, with excellent quality of life and no recurrence of the disease. In conclusion, chelation-antioxidant treatment does not appear to modify the prognosis of NH, at least in severe cases. Liver transplantation, with 50% long-term survival, remains the treatment of choice and should be promptly offered to those infants who do not improve with supportive medical treatment.

Effect of CD4+ CD25+ regulatory T-cells on CD8 T-cell function in patients with autoimmune hepatitis

BACKGROUND AND AIMS

CD4 T lymphocytes constitutively expressing the IL-2-receptor alpha-chain (CD25) (T-regs) are central to self-tolerance maintenance, preventing the proliferation and effector function of autoreactive T-cells. In autoimmune hepatitis T-regs are defective in number but maintain the ability to suppress IFNgamma production by CD4+CD25- T-cells. We have studied the ability of CD4+CD25+ (T-regs) to regulate proliferation and cytokine production by CD8 T-cells in patients with autoimmune hepatitis at diagnosis and during remission.

METHODS

Twenty-five patients were studied. T-regs were purified from PBMCs by CD4 negative selection followed by CD25 positive selection, using immunomagnetic beads. The ability of T-regs to suppress CD8 T-cell proliferation was assessed by 3H-thymidine incorporation; their ability to regulate cytokine production by intracellular cytokine staining.

RESULTS

We found that T-regs are unable to regulate CD8 T-cell proliferation and cytokine production in patients studied at diagnosis, while they suppress CD8 T-cell proliferation and induce an elevation of IL-4 producing CD8 T-cells in patients during drug-induced remission.

CONCLUSION

Inability of T-regs to regulate CD8 T-cell function at diagnosis may contribute to the initiation of autoimmune liver damage. The ability of T-regs to regulate CD8 proliferation and IL-4 production during drug-induced remission suggests a role for immunosuppressive treatment at reconstituting T-regs function.

Soluble adhesion molecule profiling in preoperative infants with biliary atresia

OBJECTIVE

Intercellular adhesion molecule (ICAM) expression in liver and bile duct remnant is a feature of the inflammatory component of biliary atresia (BA). Circulating levels of such soluble adhesion molecules (SAM) should reflect intrahepatic disease and would prove a useful adjunct in the evaluation of BA.

STUDY DESIGN

Serum ICAM-1 (sICAM-1), serum vascular cell adhesion molecule (sVCAM-1), and serum E selectin (sE-selectin) were measured by enzyme-linked immunosorbent assay in infants with BA at the time of portoenterostomy and stratified by outcome. Results are quoted as medians (range). Binary logistic regression analysis and actuarial survival curves were used to investigate the relationship of SAM profile to outcome. Significance was assumed at P values of < or = .05.

RESULTS

Sixty-one infants with BA were treated between 1996 and 2002 and at follow-up; 39 of these were alive and jaundice-free (good outcome, n = 39); 21 had been transplanted, and 1 died (poor outcome, n = 22). Preoperative values for sICAM-1 were 1233 (400-2000) ng/mL; sVCAM-1, 1204 (517-1921) ng/mL; and sE-selectin, 71 (26-192) ng/mL. sVCAM-1 (P < .0001) and sICAM-1 (P < .0001) significantly increased compared with normal control infants, although sE-selectin did not (P = .17). There was a significant correlation of age at surgery with sICAM-1 (r = 0.33, P = .01) but not with sVCAM-1 (r = 0.16, P = .23) or sE-selectin (r = 0.05, P = .70). Binary logistic regression analysis showed that the variables, sICAM-1, sE-selectin, or age at surgery, were not significant predictors of outcome, although sVCAM-1 approached significance (P = .069). A cutoff value for sVCAM-1 of 1380 ng/mL was defined by receiver operating characteristic curve analysis, and the cohort of patients with sVCAM-1 (> 1380 ng/mL) showed a significantly worse actuarial survival (P = .05).

CONCLUSION

Levels of sICAM-1 and sVCAM-1 are grossly elevated in BA, whereas sE-selectin levels are normal. Only sVCAM-1 levels have prognostic significance. SAM profiling has the potential to monitor the inflammatory process of BA and may guide more novel forms of pharmacological intervention or immunomodulation.

Susceptibility to thyroid disorders in hepatitis C

BACKGROUND & AIMS

Autoimmune thyroid disorders (AITDs) are reported, especially during interferon treatment, in chronic HCV infection, in which non-organ-specific autoantibodies (NOSAs) are common. We wondered whether seropositivity for NOSA is associated with susceptibility to AITDs.

METHODS

We evaluated thyroid function and antithyroglobulin and antithyroperoxidase antibodies in 348 Italian patients with chronic hepatitis C (34% NOSA-positive), 196 patients (33% NOSA-positive) of whom received interferon treatment.

RESULTS

At baseline, thyroid disorders were significantly more frequent in liver/kidney microsomal antibody type 1 (LKM1)-positive patients (29% vs 9%, P < .005). Similarly, on interferon therapy de novo autoimmune thyroid markers and/or symptomatic thyroid disorders appeared more often in LKM1-positive patients (50% vs 3%, P < .0001). Both female sex and LKM1 positivity were predictors of AITD, but only the latter remained significant after logistic regression analysis. Cross-reactivity to all 7 linear epitopes encoding homologous amino acid sequences shared by the HCV polyprotein, CYP2D6 (the LKM1 autoantigen), and thyroperoxidase was detected in 86% LKM1-positive HCV patients with clinical thyroid disorders, but in none of the LKM1-positive or negative HCV patients without thyroid disease, and none of an HCV-negative control group comprising subjects with LKM1-positive autoimmune hepatitis or AITD without liver disease ( P < .0001).

CONCLUSIONS

Patients receiving interferon therapy for hepatitis C seropositive for LKM1 are susceptible to develop AITDs, in association with treatment. Molecular mimicry and epitope spreading are potential pathogenic mechanisms.

Wilson's disease in children: 37-year experience and revised King's score for liver transplantation

Wilson's disease (WD) is a rare liver-based disorder of copper metabolism. Prognostic criteria described by our group in 1986 to predict death without transplantation have not been universally validated. The clinical features of 88 children were reviewed, retrospectively in 74 and prospectively in 14. Data from the retrospectively recruited patients that died or survived on long-term chelation were used to evaluate the validity of our old scoring system and to devise a new prognostic index, then assessed in the 14 prospectively recruited patients. Using the old scoring system, 5 children scoring > or = 7, the cutoff value for death without transplantation, survived, whereas 4 scoring < or = 7 died (sensitivity 87% and specificity 90%). A new index based on serum bilirubin, international normalized ratio, aspartate aminotransferase (AST), and white cell count (WCC) at presentation identified a cutoff score of 11 for death and proved to be 93% sensitive and 98% specific, with a positive predictive value of 88%. When the new index was evaluated prospectively in 14 patients, it predicted the need for transplantation in only the 4 who required it, although 1 child with a score of 11 survived on medical treatment. In conclusion, the new Wilson Index is more sensitive and specific in predicting mortality without transplantation than the old scoring system, but needs to be validated in a larger number of patients.

Risk factors for fungal infection in paediatric liver transplant recipients

Fungal infection (FI) is a major and potentially fatal complication in liver transplantation (LT). Published experience of FI in paediatric LT is limited. We therefore reviewed case records of 79 children, aged between 0.16 and 16 yr, who underwent LT between 1997 and 1998 to document the incidence of, and identify risk factors for, FI. Sixty-eight pre-, peri- and post-LT variables were assessed in relation to FI by univariate and multivariate analyses. The major indications for LT were biliary atresia in 26 (33%) patients, fulminant hepatic failure in 16 (20%) and intrahepatic cholestasis in 11 (14%); eight patients required re-LT. Thirty-two (40.5%) children developed a FI within 1 yr of LT. The median time to FI was 42 days (range 1-342 days). Candida spp. caused 29 (90.7%) FIs; 21 (66%) of these were Candida albicans. Although FI was associated with increased mortality, most patients responded well to antifungal treatment. The variables independently associated with FI were pre-LT fungal colonization and pyrexia and, post-LT, bacterial infection, Epstein-Barr virus (EBV) infection and tacrolimus administration. Identifying risk factors for FI should contribute to the development of strategies for prophylaxis or preemptive therapy.

Cystatin C, an easy and reliable marker for assessment of renal dysfunction in children with liver disease and after liver transplantation

Renal dysfunction of variable severity is being increasingly recognized as a major complication of calcineurin inhibitors (CI), in some patients even necessitating renal transplantation. Close and effective monitoring of the renal function is indicated. Current methods for this monitoring are calculation of the glomerular filtration rate (GFR) based on creatinine or exogenous substances like 51Cr-EDTA. The first method is unreliable in children and the second is expensive and cumbersome. Cystatin C has been shown to be an accurate marker of glomerular filtration but has not been evaluated in a large cohort of pediatric patients before and after liver transplantation (LT). We evaluated the accuracy of cystatin C in 62 children (30 male) with LT, who had their 51Cr-EDTA measured on 40 occasions prior to LT and on 47 occasions after LT. The reciprocal of cystatin C correlated better with 51Cr-EDTA GFR (r = .78) than the reciprocal of creatinine (r = .40). Diagnostic accuracy in the identification of reduced GFR was assessed by ROC analysis. Cystatin C yielded the highest area under the ROC curve (AUC) in all groups assessed. From these data a cutoff level of cystatin C predicting 51Cr-EDTA GFR < 80 ml/min/1.73 m2 was calculated. A level of 1.06 mg/L was found to have a sensitivity of 91% and a specificity of 81%. Applying this cutoff level in our patient group would have avoided 51Cr-EDTA GFR estimation in 43 of the 87 estimations. In conclusion, the use of this simple test could be recommended as screening of renal dysfunction in children with liver disease and after LT.

Hepatocyte transplantation for inherited factor VII deficiency

Hepatocyte transplantation has been investigated in patients with liver-based metabolic disorders and acute liver failure. We report the first use of hepatocyte transplantation in two brothers with severe inherited coagulation factor VII deficiency. Patient 1 received a total of 1.09x10(9) cryopreserved hepatocytes, and patient received 2.18x10(9) fresh and cryopreserved hepatocytes through a Hickman line inserted in the inferior mesenteric vein. Infusion of isolated human hepatocytes improved the coagulation defect and markedly decreased the requirement for exogenous recombinant factor VII (rFVIIa) to approximately 20% of that before cell transplantation. In both patients, episodes of line sepsis were associated with an increase in rFVIIa requirement. Six months posthepatocyte transplantation, higher rFVIIa doses were required, suggesting loss of transplanted hepatocyte function. Because of increasing problems with venous access and long-term uncertainty of the efficacy of hepatocyte transplantation, orthotopic liver transplantation was performed successfully in both cases.

Treatment challenges and investigational opportunities in autoimmune hepatitis

New drugs and advances in molecular biology afford opportunities to upgrade the treatment of autoimmune hepatitis. The aims of this study were to define treatment problems, identify possible solutions, and stimulate investigations to improve patient care. A clinical subcommittee of the International Autoimmune Hepatitis Group reviewed current management difficulties and proposed corrective actions. The assessment of new front-line and salvage therapies for adults and children were given top priority. Cyclosporine and mycophenolate mofetil were endorsed as drugs worthy of rigorous study in severe disease, and budesonide was endorsed for study as front-line therapy in mild disease. Diagnostic criteria and treatment regimens for children required codification, and pharmacokinetic studies were encouraged to develop optimal dosing schedules based on therapeutic ranges. Collaborative efforts were proposed to help understand racial, geographical, and genetic factors affecting outcome and to establish definitions and therapies for variant syndromes and graft dysfunction after transplantation. The development of experimental animal models was deemed essential for the study of site-specific molecular interventions, and gene therapy was endorsed as a means of bolstering reparative processes. In conclusion, evolving pharmacological and technical advances promise to improve the treatment of autoimmune hepatitis, and investigations of these advances are timely, feasible, and necessary.

Mechanisms of autoimmune hepatitis

Autoimmune hepatitis (AIH) is a progressive inflammatory liver disease with a female preponderance, responsive to immunosuppressive treatment. Two types of AIH are described: type 1 AIH is characterized by positivity for smooth muscle and/or antinuclear antibody, while type 2 AIH is positive for liver kidney microsomal type 1 antibody. The putative mechanisms leading to the development of this condition include genetic predisposition to autoimmunity through possession of specific human leukocyte antigen alleles, immune reactions to liver cell antigens, possibly triggered by a mechanism of molecular mimicry, where immune responses to external pathogens, e.g. viruses, become directed toward structurally similar self-components, and an impairment in immune regulation. AIH has been described to arise de novo after liver transplantation. The mechanisms leading to post-transplant autoimmunity remain to be defined.

Approaches to acute liver failure in children

Acute liver failure (ALF) is a rare but often fatal disorder in childhood. Its aetiology includes infections, toxins, metabolic disorders, infiltrative diseases, autoimmune hepatitis, ischaemia, irradiation damage, but in a high proportion of cases it remains unknown. In contrast to adults, in children with ALF hepatic encephalopathy can be a late event, and may not develop at all, despite a lethal outcome, particularly in infants. Children with ALF should be managed in experienced centres with facilities for liver transplantation. Transplantation should be offered only if the underlying disease is treatable by liver replacement and if the prognosis of transplant is better than that of the underlying disease, as in many cases of ALF the liver has the potential to recover with supportive treatment, if the child is kept alive and stable long enough. Universally accepted criteria for listing for transplantation have not been defined as yet. In our centre, maximum INR, bilirubin level, and white cell count, together with age have proven to be reliable predictors of outcome. Future efforts in the management of ALF should concentrate on designing efficient supportive therapy and specific treatments to provide effective non-transplant therapeutic options.

Antibodies to soluble liver antigen and alpha-enolase in patients with autoimmune hepatitis

BACKGROUND: Antibodies to a cytosolic soluble liver antigen (SLA) are specifically detected in patients with autoimmune hepatitis (AIH). The target of anti-SLA has been identified as a ~50 kDa UGA serine tRNA-associated protein complex (tRNP(Ser)Sec), through the screening of cDNA libraries. A recent report questioned the identity of tRNP(Ser)Sec as the real SLA antigen. The latter study identified alpha-enolase as a major anti-SLA target, through proteomic analysis. METHODS: In an attempt to explain the observed discrepancy we have investigated reactivity of SLA positive sera against alpha-enolase and tRNP(Ser)Sec using rat and primate liver homogenate and the recombinant antigens. Thirty-three serum samples, 11 from SLA-positive patients and 22 from SLA negative controls were investigated. SLA antibodies were detected by an inhibition ELISA and confirmed by immunoblot using human liver homogenate. Autoantibody reactivity was further evaluated using preparations of primate and rat liver homogenates. Anti-alpha-enolase antibody reactivity has been tested by immunoblot using recombinant alpha-enolase. An affinity purified goat polyclonal anti-alpha-enolase IgG antibody was used as reference serum sample. Anti-tRNP(Ser)Sec antibody reactivity was detected by ELISA or dot blot using recombinant tRNP(Ser)Sec antigen. RESULTS AND DISCUSSION: The affinity purified IgG antibody directed to human alpha-enolase gave a band of approximately 48 kDa in both human and rat liver homogenates. A high titre anti-tRNP(Ser)Sec antibody serum gave a single band of ~50 kDa in both liver preparations. All but one anti-SLA antibody positive sera reacted with a ~50 kDa but none immunofixed a 48 kDa band. All anti-SLA antibody positive sera reacted strongly with the recombinant full length tRNP(Ser)Sec protein. None of the anti-SLA negative sera reacted with tRNP(Ser)Sec. Anti-SLA positive, and anti-SLA negative sera reacted equally against recombinant alpha-enolase by immunoblot. Pre-incubation of anti-SLA positive sera with tRNP(Ser)Sec completely abolished the 50 kDa band. The findings of the present study indicate that alpha-enolase and tRNP(Ser)Sec are both expressed in primate and rat liver and have a respective MW of 48 and 50 kDa. They also show that anti-tRNP(Ser)Sec - but not anti-alpha-enolase - correlates with anti-SLA antibody reactivity. CONCLUSION: Our findings indicate that tRNP(Ser)Sec is the most likely target of anti-SLA.

Liver disease in children with primary immunodeficiencies

OBJECTIVE

To investigate clinical features and to establish optimal management in children with primary immunodeficiency (PID) and liver disease. Study design A retrospective analysis of medical records of 147 children with PID who presented with abnormal liver tests to a tertiary center.

RESULTS

Clinical evidence of liver disease was documented in 35 (23.8%) patients. Of these, 22 (63%) had hepatomegaly and 14 (40%) had splenomegaly. Sclerosing cholangitis (SC) was diagnosed in 21 children (60%), based on radiological and histological criteria; 4 patients with SC on cholangiography had no biliary changes in the liver biopsy. Ultrasonography demonstrated a dilated biliary system in 14 (67%) children with SC. Of 27 children investigated for Cryptosporidium parvum (CSP), 12 (44%) were positive, including 9 of 12 with SC. Overall, 7 (20%) patients died, including 3 boys with disseminated recurrent CSP infection after successful liver transplantation (LT). Temporary deterioration of liver injury was observed in 2 CSP-positive boys with CD40 ligand deficiency (CD40LD) who were undergoing nonmyeloablative hematopoietic stem cell transplantation (HSCT). Successive liver and HSCT was curative in 1 patient with CD40LD and end-stage liver disease.

CONCLUSION

SC is the most common hepatic complication of PID. Mild liver involvement could be arrested by early nonmyeloablative HSCT, whereas advanced disease may warrant combined liver and HSCT.

One liver, three recipients: segment IV from split-liver procedures as a source of hepatocytes for cell transplantation

Hepatocyte transplantation is emerging as a possible treatment for patients with acute liver failure and liver-based metabolic disorders. With the limited availability of donor tissue, it is important to find new sources of liver tissue for isolation of high-quality hepatocytes. Segment IV with or without the caudate lobe was removed during three split-liver procedures. Hepatocytes were isolated from the tissues using a collagenase perfusion technique under strict sterile conditions. The mean number of hepatocytes that were isolated was 5.14 x 10(8) cells with a mean cell viability of 89%. Two of the hepatocyte preparations were used for cell transplantation in a 1-day-old boy with an antenatal diagnosis of a severe urea cycle defect caused by ornithine transcarbamylase deficiency. The six recipients of split-liver grafts demonstrated no complications related to the removal of segment IV. Segment IV with or without the caudate lobe obtained from split-liver procedures is potentially a good source of high-quality hepatocytes for cell transplantation.

Impairment of CD4(+)CD25(+) regulatory T-cells in autoimmune liver disease

BACKGROUND/AIMS

CD4(+) lymphocytes constitutively expressing the IL-2-receptor alpha-chain (CD25) regulate the activation of CD4 and CD8 autoreactive T-cells by suppressing their proliferation and effector function. The aim of this study is to: (1) measure the percentage of CD4(+)CD25(+) T-cells (T-regs) in patients with autoimmune liver disease at presentation and during remission, (2) correlate their frequency with disease activity, (3) determine their ability to expand and (4) to inhibit interferon-gamma (IFNgamma) production by CD4(+)CD25- T-cells.

METHODS

41 patients were studied. Percentage of T-regs was determined on peripheral blood mononuclear cells (PBMCs) by triple-colour flow cytometry; their ability to expand by exposing PBMCs to a T-cell expander (CD3/CD28 Dynabeads); their immunoregulatory function by measuring their ability to suppress IFNgamma production by CD4(+)CD25(-) T-cells.

RESULTS

T-regs were significantly less in patients than in controls, and at diagnosis than during remission. Their percentage was inversely correlated with titres of anti-liver kidney microsomal and soluble liver antigen autoantibodies. T-regs ability to expand was significantly lower in patients than in controls, but that to suppress IFNgamma production by CD4(+)CD25(-) T-cells was maintained.

CONCLUSIONS

Decreased T-regs numbers and ability to expand may favour the emergence of liver-targeted autoimmunity, despite preserved suppressor function. Treatment should aim at increasing T-regs number.

Dehydrated hereditary stomatocytosis is associated with neonatal hepatitis

Dehydrated hereditary stomatocytosis (DHSt) is an inherited haemolytic anaemia associated with increased red cell membrane permeability to Na(+) and K(+). It is increasingly recognized that a syndrome of self-limiting perinatal ascites can accompany the haemolysis. The cause of the perinatal ascites is unknown, and it has been argued that this could be due to cardiovascular, hepatic or lymphatic problems. We describe the case of a 16-year-old girl who presented neonatally with abnormal liver function tests and ascites. She was extensively investigated at that time. A liver biopsy showed hepatitis and fatty changes. Her ascites resolved within 6 months. At the age of 15 years, she developed an episode of acute haemolysis and was re-investigated. A diagnosis of DHSt was made. Pseudohyperkalaemia, due to ex vivo loss of K(+) from red cells, was present. This study confirms the previously noted association of DHSt, pseudohyperkalaemia and perinatal ascites, and suggests that the latter is of predominantly hepatic origin.

Autoimmune hepatitis

Autoimmune hepatitis (AIH) is characterised histologically by interface hepatitis, and serologically by the presence of non-organ and liver specific autoantibodies and increased levels of immunoglobulin G. Its onset is often ill-defined, frequently mimicing acute hepatitis. AIH usually responds to immunosuppressive treatment, which should be instituted as soon as diagnosis is made. Two types of AIH are recognized according to seropositivity for smooth muscle and/or antinuclear antibody (SMA/ANA, type 1 AIH) or liver kidney microsomal type 1 antibody (LKM1, type 2 AIH). There is a female predominance in both. LKM1 positive patients tend to present more acutely, at a younger age and commonly have immunoglobulin A deficiency, while duration of symptoms before diagnosis, clinical signs, family history of autoimmunity, presence of associated autoimmune disorders, response to treatment and long-term prognosis are similar in the 2 groups. Susceptibility to AIH type 1 is conferred by possession of HLA DR3 and DR4, while to AIH type 2 by possession of HLA DR7. Liver damage is likely to derive from an immune reaction to liver cell antigens, possibly triggered by a mechanism of molecular mimicry, where immune responses to external pathogens, e.g. viruses, become directed towards structurally similar self-components. In AIH this process would be perpetuated by impairment in immune regulation.