Autoimmune hepatitis in childhood: a 20-year experience

To determine the clinical, biochemical, and histological features, and outcome of childhood autoimmune hepatitis (AIH), we reviewed the medical records of 52 children with AIH, 32 (median age: 10 [2-15] years) anti-nuclear and/or smooth muscle antibody (ANA/SMA) positive, 20 (7 [0.8-14] years) liver/kidney microsomal antibody (LKM-1) positive, with median follow-up of 5 years (range 0.3-19). At presentation: 56% had symptoms of prolonged acute hepatitis; LKM-1 positive were younger (P = .011), with higher bilirubin (P = .007), and AST (P = .047); ANA/SMA positive had lower albumin (P = .023); 69% ANA/SMA positive, and 38% LKM-1 positive were cirrhotic (P = .080). ANA/SMA positive had increased frequency of HLA haplotype A1/B8/DR3/DR52a compared with controls (53% vs. 14%, P < .001). Of six (5 LKM-1 positive) with fulminant hepatitis, four were transplanted, one died, and one ANA/SMA positive improved with immunosuppression. Of 47 treated with immunosuppression, 2 (1 LKM-1 positive) died with no remission and 4 (2 LKM-1 positive) were transplanted 8 to 14 years after diagnosis. Immunosuppression was stopped successfully in 19% of ANA/SMA positive after a median of 3 years of treatment, but in none of LKM-1 positive. Baseline bilirubin and international normalized prothrombin ratio (INR) were independent variables predictive of outcome. In conclusion, ANA/SMA positive and LKM-1 positive AIH in childhood have clinical, biochemical, and histological differences, but similar severity and long-term outcome.

Autoimmune hepatitis/sclerosing cholangitis overlap syndrome in childhood: a 16-year prospective study

To investigate whether sclerosing cholangitis with an autoimmune serology characteristic of autoimmune hepatitis (AIH) and AIH are distinct entities, we studied 55 consecutive children with clinical and/or biochemical evidence of liver disease and circulating antinuclear (ANA), anti-smooth muscle (SMA), and/or liver-kidney-microsomal type 1 (LKM1) autoantibodies. They underwent liver biopsy, direct cholangiography, sigmoidoscopy, and rectal biopsy at presentation. Twenty-eight were diagnosed as AIH in the absence and 27 autoimmune sclerosing cholangitis (ASC) in the presence of radiological features of cholangiopathy. Twenty-six ASC and 20 AIH had ANA and/or SMA; 1 ASC and 8 AIH LKM1 autoantibody. Similarities between the 2 conditions included most clinical and biochemical parameters and a lower frequency of HLA DR4. Inflammatory bowel disease and histological biliary changes were more common in ASC; coagulopathy, hypoalbuminemia, lymphocytic periportal hepatitis, and HLA DR3 were more common in AIH. Histological biliary changes were observed in 65% of ASC and 31% of AIH patients. Eighty-nine percent responded to immunosuppression. Follow-up liver biopsies from 17 ASC and 18 AIH patients had similarly reduced inflammatory activity and no progression to cirrhosis. Sixteen follow-up cholangiograms from AIH patients and 9 from ASC patients were unchanged, while 8 ASC patients showed a progressive cholangiopathy. One child with AIH and ulcerative colitis developed sclerosing cholangitis 8 years after presentation. At 2 to 16 years (median, 7 years) from presentation, all patients are alive, including 4 ASC patients who underwent liver transplantation. In conclusion, ASC and AIH are similarly prevalent in childhood; cholangiography is often needed to distinguish between these 2 entities, which are likely to lie within the same disease process.

Hepatitis C virus antibodies in chronic active hepatitis: pathogenetic factor or false-positive result?

An enzyme immunoassay (Ortho-HCV ELISA) for antibodies against the hepatitis C virus (HCV) was used to test 143 serum samples from 53 patients with autoimmune chronic active hepatitis (AI-CAH). Optical density (OD) values in the assay correlated closely with serum globulin (r = 0.8846, p much less than 0.0005) and IgG (r = 0.6281, p less than 0.0005) concentrations but not with immunosuppressant therapy. OD values were positive in 20 (65%) of 31 with active disease and in only 1 (5%) of 22 in remission (p less than 0.0005). The association between positive results and active disease and high serum globulin levels was confirmed by serial studies in 6 of the patients. In contrast, none of 31 patients with primary biliary cirrhosis and only 2 of 24 with non-hepatic disorders associated with high IgG concentrations were positive, and these controls showed no correlation between OD values and serum globulins or IgG. The findings suggest that serum from AI-CAH patients may contain a component that gives false-positive results in the assay.

Incubation phase of acute hepatitis B in man: dynamic of cellular immune mechanisms

After hepatitis B virus (HBV) infection, liver injury and viral control have been thought to result from lysis of infected hepatocytes by virus-specific cytotoxic T cells. Patients are usually studied only after developing significant liver injury, and so the viral and immune events during the incubation phase of disease have not been defined. During a single-source outbreak of HBV infection, we identified patients before the onset of symptomatic hepatitis. The dynamics of HBV replication, liver injury, and HBV-specific CD8+ and CD4+ cell responses were investigated from incubation to recovery. Although a rise in alanine transaminase (ALT) levels was present at the time of the initial fall in HBV-DNA levels, maximal reduction in virus level occurred before significant liver injury. Direct ex vivo quantification of HBV-specific CD4+ and CD8+ cells, by using human leukocyte antigen (HLA) class I tetramers and intracellular cytokine staining, showed that adaptive immune mechanisms are present during the incubation phase, at least 4 weeks before symptoms. The results suggest that the pattern of reduction in HBV replication is not directly proportional to tissue injury during acute hepatitis B in humans. Furthermore, because virus-specific immune responses and significant reductions in viral replication are seen during the incubation phase, it is likely that the immune events central to viral control occur before symptomatic disease.

Direct ex vivo analysis of hepatitis B virus-specific CD8(+) T cells associated with the control of infection

BACKGROUND & AIMS

Cytotoxic T cells have been suggested to be responsible for lysis of hepatitis B virus (HBV)-infected hepatocytes and control of virus infection. The frequency, kinetics, phenotype, and capacity for clonal expansion of circulating HBV-specific CD8 cells were analyzed directly in patients with acute HBV infection to clarify their pathogenetic role.

METHODS

Three HLA-A2 peptide tetramers able to visualize HBV core, envelope, and polymerase epitope-specific cytotoxic T lymphocytes were synthesized and used for flow cytometric analysis of antigen-specific populations.

RESULTS

Tetramer-positive cells specific for the core 18-27 epitope were found at a higher frequency than those specific for polymerase 575-583 and envelope 335-343 epitopes in most patients with acute HBV. The number of HBV-specific CD8 cells was highest during the clinically acute stage of infection and decreased after recovery. These cells expressed an activated phenotype and had an impaired capacity to expand in vitro and to display cytolytic activity in response to peptide stimulation. Recovery of these functions was observed when the frequency of specific CD8 cells decreased, coincident with a progressive decrease in their expression of activation markers.

CONCLUSIONS

This study provides the first ex vivo evidence that the highest frequency of circulating HBV-specific CD8 cells coincides with the clinically acute phase of hepatitis B. These cells exhibit an activated phenotype with limited further proliferative capacity that is restored during recovery.

De-novo autoimmune hepatitis after liver transplantation

BACKGROUND

Late graft dysfunction that does not result from recognised causes, such as rejection, infection, or vascular or biliary complications, can occur after liver transplantation. We investigated a particular type of unexplained graft dysfunction that is associated with autoimmune features in children who underwent transplantation at our unit between 1991 and 1996.

METHODS

Seven (4%) of 180 liver-transplant recipients developed an unexplained but characteristic form of graft dysfunction (five boys, two girls; median age at presentation 10.3 years, range 2.0-19.4). The median period after surgery was 24 months (6-45). The indications for transplantation had been extrahepatic biliary atresia (four patients), Alagille's syndrome (one), drug-induced acute liver failure (one), and alpha1-antitrypsin deficiency (one). Four patients were on triple immunosuppression with cyclosporin, azathioprine, and prednisolone; and three were on tacrolimus. Immunoglobulin measurements, autoantibody studies, serological studies, and HLA typing were undertaken. Liver-biopsy samples were taken.

FINDINGS

Infectious and surgical complications were excluded. Liver-biopsy samples showed the histological changes of chronic hepatitis, including portal and periportal hepatitis with lymphocytes and plasma cells, bridging collapse, and perivenular-cell necrosis without changes typical of acute or chronic rejection. All patients had high concentrations of IgG (median 22 g/L [range 17.2-34.4]) and high titres of autoantibodies. All but one patient responded to prednisolone 2 mg/kg daily and an increase in or addition of azathioprine (1.5 mg/kg daily) within a median of 32 days (7-316). One responder relapsed owing to poor compliance but went into remission after treatment was restored. All six respondents remain in remission on a reduced dose of prednisolone (5-10 mg/day) and 1.5 mg/kg daily azathioprine at a median of 283 days (range 108-730) follow-up.

INTERPRETATION

Our data show that symptoms of autoimmune hepatitis, which are responsive to the classical treatment for this condition, can appear in liver-transplant patients while they are on anti-rejection immunosuppression. Whether the liver damage in these patients is a form of rejection or the consequence of autoimmune attack has yet to be established.

Influence of delta infection on severity of hepatitis B

The prevalence of serum markers of primary delta infection was determined in 532 patients with acute benign hepatitis B seen in Italy, and in 111 patients with fulminant hepatitis B seen in Italy, France and England. Patients with fulminant hepatitis had significantly higher prevalence of delta markers (43/111, 39%) than did those with benign hepatitis (101/532, 19%). In 25 of the 43 patients with delta-positive fulminant hepatitis, serum markers indicated a primary hepatitis B infection while in the remaining 18, IgM antibody to hepatitis B core antigen was absent, indicating that hepatitis B preceded superinfection with the delta agent. The increased morbidity of HBsAg hepatitis with delta infection may result from the cumulative simultaneous exposure to hepatitis B virus and delta, or from superinfection of HBsAg carriers with delta.

Antibodies to the surface of halothane-altered rabbit hepatocytes in patients with severe halothane-associated hepatitis

Circulating antibodies reacting specifically with the cell membrane of hepatocytes isolated from halothane-anesthetized rabbits were detected in nine of 11 patients with fulminant hepatic failure after helothane-induced anesthesia. The immunoglobulin deposition, as revealed by immunofluorescence, showed a granular pattern on the hepatocyte surface membrane. Preincubation of halothane-pretreated, but not of control, hepatocytes with serum containing this antibody rendered them susceptible to cytotoxic effects of normal lymphocytes in vitro. Control studies using serum from subjects repeatedly exposed to halothane without the development of liver damage, and from patients with viral and toxic liver injury have confirmed the specificity of these findings to serve halothane-associated liver injury. These results provide further evidence of an immunologic component in this condition.

Antibodies to hepatitis C virus in autoimmune liver disease: evidence for geographical heterogeneity

To resolve conflicting reports about the occurrence of antibodies against hepatitis C virus (HCV) in patients with autoimmune chronic active hepatitis (AI-CAH), sera from UK and Italian patients were tested with the original anti-HCV assay (Ortho) and a novel anti-HCV assay (UBI) based entirely on synthetic HCV peptides. 28 (60%) of 47 Italian patients with type-1 AI-CAH were anti-HCV-positive by Ortho ELISA, 25 of whom were also strongly positive by the UBI assay. 15 (60%) of 25 UK patients with type-1 AI-CAH were HCV-positive by Ortho ELISA but only 2 were positive by the UBI assay. Similarly, 29 (88%) of 33 Italian patients with type-2 AI-CAH, but 0 of 10 UK patients, were very strongly anti-HCV-positive with the UBI assay. Italian patients with AI-CAH appear to have a high frequency of genuine exposure to HCV, whereas seropositivity by the Ortho HCV ELISA in UK patients is likely to represent a false-positive result. These findings indicate important geographical and/or genetic influences in autoimmune liver disease among different populations.

Molecular mimicry and autoimmune liver disease: virtuous intentions, malign consequences

The pathogenesis of autoimmune liver disease and autoimmunity associated with chronic viral hepatitis remains poorly understood. One of the major hurdles to a deeper understanding of these pathological processes is the absence of clearly defined inductive mechanisms, which, if identified and characterised, could guide clinical strategies for their prevention or allow therapeutic intervention. Molecular mimicry leading to crossreactive autoimmune responses has gained strong experimental support in the past decade. A fundamental premise of this hypothesis is the involvement of a mimicking environmental trigger. In view of the numerous viral and bacterial agents epidemiologically linked to autoimmune liver diseases, we and others have proposed molecular mimicry to be an important mechanism in these diseases. We also propose similar crossreactive mechanisms to operate in the generation of autoimmunity in viral hepatitis. This review focuses on molecular mimicry at the level of the B-cell, as few data on T-cell crossreactivity in liver disease are thus far available.

Serum autoantibodies reacting with the hepatic asialoglycoprotein receptor protein (hepatic lectin) in acute and chronic liver disorders

Circulating autoantibodies reacting with affinity-purified, hepatic asialoglycoprotein receptor protein, hepatic lectin (HL), were detected by radioimmunoassay in 15 (83%) of 18 patients with autoimmune chronic active hepatitis (AI-CAH) who had active disease, at titres that showed a positive correlation (P less than 0.05) with severity of periportal inflammation assessed histologically. In contrast, 10 AI-CAH patients whose disease was in remission were all anti-HL seronegative. Anti-HL was also detected in 16 (73%) of 22 patients with hepatitis B virus-related CAH-a similar frequency to that in active AI-CAH but at significantly lower (P less than 0.005) titres. Only 1 of 8 patients with chronic active liver disease due to presumed non-A, non-B (NANB) viral infection and 5 (22%) of 23 with primary biliary cirrhosis were anti-HL seropositive (P less than 0.001 vs active AI-CAH and HBV-CAH) and there was no correlation with severity of periportal inflammation. Anti-HL antibodies were also found in sera from 7 (35%) of 20 patients with acute virus B hepatitis (AVH-B) but were not detected in 10 patients with AVH-A nor in 12 with AVH due to presumed NANB infection. Anti-HL was not found in sera of 12 patients with autoimmune thyroid disease. Hepatic lectin, a highly purifiable, liver-specific cell surface component, by analogy with the acetylcholine and thyrotropin receptors which are, respectively, targets of the pathogenetically-related autoimmune reactions in myasthenia gravis and autoimmune thyroid disease, may be an important target of autoreactions in liver disease.

Prevalence and clinical significance of isotype specific antinuclear antibodies in primary biliary cirrhosis

BACKGROUND

Antinuclear antibodies (ANA) giving a rim-like/membranous (RL/M) or a multiple nuclear dot (MND) pattern are highly specific for primary biliary cirrhosis (PBC). Aim and

SUBJECTS

To assess the prevalence of PBC specific ANAs, their Ig isotype, and their clinical significance in 90 PBC patients from Greece and Spain. Twenty eight patients with chronic hepatitis C, 23 patients with systemic lupus erythematosus, and 17 healthy subjects were studied as controls.

METHODS

PBC specific ANA reactivity was tested by indirect immunofluorescence using HEp2 cells as substrate and individual Ig class (IgG, IgA, IgM) and IgG subclass (IgG1, IgG2, IgG3, IgG4) specific antisera as revealing reagents.

RESULTS

Fourteen of 90 (15.6%) PBC patients had PBC specific ANA reactivity when an anti-IgG (total) antiserum was used as the revealing reagent while 58 (64.4%) were positive when specific antisera to each of the four IgG isotypes were used. The prevailing isotype was IgG3 for MND and IgG1 for RL/M. PBC patients with specific ANA, in particular of the IgG3 isotype, had significantly more severe biochemical and histological disease compared with those who were seronegative. None of the controls was positive.

CONCLUSIONS

Disease specific ANA are present in the majority of patients with PBC when investigated at the level of immunoglobulin isotype. PBC specific ANA, in particular of the IgG3 isotype, are associated with a more severe disease course, possibly reflecting the peculiar ability of this isotype to engage mediators of damage.

Type 1 diabetes mellitus in patients with chronic hepatitis C before and after interferon therapy

Type 1 diabetes mellitus is the result of an autoimmune process characterized by pancreatic beta cell destruction. It has been reported that chronic hepatitis C infection is associated with type 2 diabetes mellitus, but not with type 1. Although the prevalence of markers of pancreatic autoimmunity in hepatitis C virus-positive patients is not significantly different to that reported in the general population, it increases during alpha-interferon therapy from 3 to 7%, probably due to the immunostimulatory effects of this cytokine. To date, 31 case reports of type 1 diabetes mellitus related to interferon treatment have been published. Type 1 diabetes mellitus occurs more frequently in patients treated for chronic hepatitis C than for other conditions and is irreversible in most cases. In 50% of these patients, markers of pancreatic autoimmunity predated treatment, the majority of cases having a genetic predisposition. Thus, in predisposed individuals, alpha-interferon can either induce or accelerate a diabetogenic process already underway. We suggest that islet cell autoantibodies and glutamic acid decarboxylase autoantibodies should be investigated before and during interferon treatment in order to identify subjects at high risk of developing type 1 diabetes mellitus.

Mimicry between the hepatitis C virus polyprotein and antigenic targets of nuclear and smooth muscle antibodies in chronic hepatitis C virus infection

Autoantibodies to smooth muscle (SMA) and nuclear components (ANA) arise in the natural course of chronic infection with hepatitis C virus. In view of the growing evidence for 'molecular mimicry' as a mechanism of autoimmunity we investigated whether cross-reactive immune reactions between host smooth muscle/nuclear components and HCV antigens may contribute to the formation of SMA and ANA in chronic HCV infection. Computer-assisted protein database search methods were used to identify three smooth muscle (smoothelin698-717, myosin1035-1054, vimentin69-88) and three nuclear (matrin722-741, histone H2A11-30, replication protein A133-152) host antigens with the highest local sequence similarity to the HCV polyprotein and 20-mer peptides corresponding to these regions were constructed. Sera from 51 children with chronic HCV infection [median age: 8 (2-16); 27 boys], 26 SMA positive and five ANA positive, were tested for reactivity to the synthesized HCV peptides and their human homologues by enzyme linked immunosorbent assay (ELISA). Sera from patients with HBV infection and chronic liver disease of different aetiologies were used as controls. 'Double reactivity' to HCV peptides and smooth muscle/nuclear homologues was associated strongly with HCV infection (P < 0.001 for both). Humoral cross-reactivity was established as the basis for double recognition by competition ELISA. Double-reactivity to smooth muscle and HCV peptide antigens correlated with SMA positivity by indirect immunofluouresence (P = 0.05). Of 15 patients double-reactive to myosin1035-1054 and its HCV homologue, 13 recognized whole myosin by immunoblot. These results suggest that ANA and SMA in chronic HCV infection may arise, at least in part, as a consequence of cross-reactive immune responses to HCV and host smooth muscle/nuclear antigens.

Genetically determined low C4: a predisposing factor to autoimmune chronic active hepatitis

Of 26 patients with autoimmune chronic active hepatitis (CAH) starting in childhood 18 (69%) had low C4 and 5 (19%) had low C3 serum levels. Impaired hepatic synthesis and immune-consumption were unlikely since transferrin levels were normal in all patients, albumin levels were persistently low in only 3, and only 3 had raised levels of activation fragment C3d. C4d was normal in all patients studied. In the families of 12 probands with low C4, 7 parents had low C4 and 2 had levels which were at the lower limit of normal. 5 of 10 siblings from 5 families had low C4. These results suggest that low C4 levels in CAH are genetically determined. C4 phenotyping in 20 patients and in 26 parents showed that 90% and 81%, respectively, had null allotypes at either the C4A or C4B locus compared with 59% in controls, indicating that defective expression of structural genes may contribute to the observed C4 deficiency.

T cell activation and disease severity in HIV infection

In vitro studies have indicated that T lymphocyte activation may be of importance in the pathogenesis of HIV infection. In order to define the role of immune activation in vivo, we assessed the expression of the T cell activation markers HLA-DR and CD25 by flow cytometry in peripheral blood in relation to disease severity and the surrogate markers CD4 and beta 2-microglobulin in 157 patients with HIV infection and 53 healthy seronegative blood donors. Percentage levels of CD3+HLA-DR+ T lymphocytes were significantly higher (P < 0.0001) and percentage levels of CD3+CD25+ T lymphocytes significantly lower (P < 0.0001) in all HIV+ patients compared with controls. A significant correlation was observed between increasing percentage levels of CD3+HLA-DR+ T lymphocytes and both declining CD4 counts (r = 0.52; P < 0.001) and increasing beta 2-microglobulin levels (r = 0.56; P < 0.001). Percentage levels of CD4+HLA-DR+ and CD4+ CD25+ lymphocytes were significantly higher in all HIV+ patients compared with controls (P < 0.001). Levels of activated (HLA-DR+ and CD25+) CD4+ lymphocytes showed a significant step-wise linear increase with increasing disease severity (P < 0.001). High levels of CD3+HLA-DR+ T lymphocytes were found in a greater proportion (81.8%) of asymptomatic HIV+ patients (Centres for Disease Control (CDC) group II) than low CD4 counts (51.5%) (P < 0.001). Compared with controls, HIV+ patients had higher percentage levels of CD8+HLA-DR+ lymphocytes (P < 0.001), but similar levels of CD8+CD25+ lymphocytes. These results indicate that T cell activation is not only a consistent but also an early feature in HIV infection. Monitoring levels of activated T cells and their subsets is of value in assessing progression of HIV-related disease.

Heart rate variability and early recurrence of atrial fibrillation after electrical cardioversion

OBJECTIVES

The study evaluated the role of the autonomic nervous system in atrial fibrillation (AF) recurrence.

BACKGROUND

Early recurrence of AF after cardioversion (CV) is attributed to electrical remodeling. The possibility that an abnormal autonomic modulation might contribute to this phenomenon has not yet been adequately tested.

METHODS

We analyzed short-term heart rate variability (HRV) in 93 patients with persistent AF and on chronic amiodarone treatment, after restoration of sinus rhythm by electrical CV.

RESULTS

Two weeks later, 25 patients presented with AF. Spectral analysis of HRV revealed that patients wi

Immunohistochemical features of the portal tract mononuclear cell infiltrate in chronic aggressive hepatitis

The portal tract mononuclear cell infiltrate has been characterised in 28 liver biopsy samples showing features of chronic aggressive hepatitis from 12 patients with autoimmune chronic active hepatitis, 12 with primary sclerosing cholangitis, and four with other chronic liver diseases (two with alpha 1-antitrypsin deficiency, one with Wilson's disease, and one with chronic hepatitis B infection). In all patients liver disease had started in childhood. The mononuclear cell infiltrate was investigated by a two step immunoperoxidase technique using monoclonal antibodies to: total, alpha/beta T cell receptor positive, helper/inducer, suppressor/cytotoxic T lymphocytes; B lymphocytes; killer/natural killer cells; monocyte/macrophages; and to the activation markers HLA-DR antigens, interleukin 2 receptor (IL-2R), transferrin receptor, and 4F2Ag. In all samples the infiltrate consisted of mainly alpha/beta T cell receptor T lymphocytes. Although T helper/inducer cells predominated in patients with autoimmune chronic active hepatitis, T suppressor/cytotoxic lymphocytes were preponderant in patients with primary sclerosing cholangitis and the other chronic liver diseases. Killer/natural killer cells accounted for up to 25% of the mononuclear cell infiltrate in patients with autoimmune chronic active hepatitis, being rare or absent in the other diseases. Monocytes/macrophages were always found, but they were more numerous in primary sclerosing cholangitis than in the other chronic liver diseases. B lymphocytes were rare or absent in all subjects. Activated mononuclear cells were present in all subjects, but although in patients with autoimmune chronic active hepatitis and primary sclerosing cholangitis most cells of the infiltrate expressed HLA-DR antigens and up to 75% IL-2R, in other forms of chronic liver diseases HLA-DR positive cells were less common and IL-2R positive cells ere rare or absent. These results show that the cells responsible for the histological characteristics of chronic aggressive hepatitis vary in their functional phenotype and state of activation according to the type of underlying liver disorder, confirming the involvement of different pathogenetic mechanisms.

T-cell-directed hepatocyte damage in autoimmune chronic active hepatitis

To investigate the function of activated T lymphocytes in autoimmune chronic active hepatitis, 7 of 15 T-cell clones from the peripheral blood of 8 patients were studied. These clones showed specificity for liver-membrane antigen with proliferation when stimulated by rabbit liver cell membranes. 6 of these clones reacted with liver-specific lipoprotein complex, and 1 clone (and 3 subclones) responded to the asialoglycoprotein receptor (ASGPR), both known targets of immune attack in autoimmune chronic active hepatitis. 2 of these clones stimulated autologous B lymphocytes to produce liver-membrane-specific autoantibodies and antibody to the ASGPR. These results suggest that liver-membrane-specific activated T lymphocytes in peripheral blood may be important in the autoimmune attack of chronic active hepatitis.

Autoantibody prevalence in children with liver disease due to chronic hepatitis C virus (HCV) infection

HCV infection and interferon-alpha (IFN-alpha) therapy have been associated with autoimmunity. To assess whether chronic liver disease (CLD) due to HCV infection or its treatment with IFN-alpha cause autoimmune manifestations, the prevalence of tissue autoantibodies in 51 children with chronic HCV infection and 84 with other CLD was analysed by standard techniques. Sixty-five percent of patients with chronic HCV infection, 66% with chronic hepatitis B infection and 60% with Wilson's disease were positive for at least one autoantibody. In the 51 subjects with chronic HCV infection (29 treated with IFN-alpha, 22 untreated), tested on 165 occasions over a median of 9 months (range 5-42 months), autoantibodies to nuclei (ANA), smooth muscle (SMA), gastric parietal cell (GPC) and/or liver kidney microsomal type 1 (LKM-1) were similarly prevalent in treated and untreated patients (90% versus 68%, P = 0.12). Positivity for SMA was present in 67%, GPC in 32%, ANA in 10%, LKM-1 in 8% of cases. Treatment with IFN-alpha had to be suspended due to transaminase elevation in one SMA-positive, one ANA-positive but in three of four LKM-1-positive patients. Our results show that: (i) autoantibodies are common in viral-induced hepatitis and Wilson's disease; (ii) positivity for SMA, GPC, ANA is part of the natural course of chronic HCV infection, their prevalence being unaffected by IFN-alpha; and (iii) IFN-alpha should be used cautiously in the treatment of LKM-1/HCV-positive patients.

Class I and class II major histocompatibility complex antigen expression on hepatocytes: a study in children with liver disease

Controversy exists regarding major histocompatibility complex antigen expression on hepatocytes. In this study, hepatocyte expression of class I and II major histocompatibility complex antigens was investigated in diseased and normal livers, using indirect immunofluorescent staining of mechanically isolated, viable hepatocytes. Hepatocytes were obtained from 76 children: 10 with autoimmune chronic active hepatitis, nine with primary sclerosing cholangitis, nine with chronic hepatitis B virus infection, five after liver transplantation, 19 with extrahepatic biliary atresia, 11 with alpha 1-antitrypsin deficiency, four with idiopathic neonatal hepatitis and nine with histologically normal liver. Immunohistochemistry was performed in all cases; flow cytofluorimetry was performed for class I antigens in 38 cases and performed for class II antigens in 18 cases. From three children with autoimmune chronic active hepatitis and two with chronic hepatitis B virus infection, isolated hepatocytes were also incubated with gamma-interferon before staining and analysis. By fluorescence microscopy, class I antigens were detected on hepatocytes from all children, the highest percentage (100%) of positive cells and the most intense staining were observed in untreated patients with autoimmune chronic active hepatitis or primary sclerosing cholangitis and in those with acute rejection of a liver transplant. Reduced class I antigen expression occurred in chronic hepatitis B virus infection. Class II antigens were only detected on hepatocytes from eight patients: three with autoimmune chronic active hepatitis and five with primary sclerosing cholangitis, all untreated. Flow cytofluorimetric analysis confirmed the results obtained by fluorescence microscopy, but it also demonstrated a weak class II antigen expression during liver allograft rejection.(ABSTRACT TRUNCATED AT 250 WORDS)

Multiple viral/self immunological cross-reactivity in liver kidney microsomal antibody positive hepatitis C virus infected patients is associated with the possession of HLA B51

Liver Kidney Microsomal autoantibody type 1(LKM1) directed to cytochrome P4502D6 (CYP2D6) characterises autoimmune hepatitis type-2 (AIH-2), but is also found in a proportion of chronic hepatitis C virus (HCV) infected patients, CYP2D6252-271 being a major B- cell autoepitope. Molecular mimicry and immunological cross-reactivity between CYP2D6252-271, HCV polyprotein and the infected cell protein 4 (ICP4) of herpes simplex virus type 1 (HSV-1) have been suggested as triggers for the induction of LKM1, but reactivity and cross-reactivity to the relevant sequences have not been investigated experimentally. CYP2D6252-271 and its viral homologues were constructed and tested by ELISA in the sera of 46 chronically infected HCV patients, 23 of whom were LKM1 positive. Reactivity to the E1 HCV and ICP4 HSV1 mimics was frequently found in HCV infected patients irrespectively of their LKM1 status; viral/self cross-reactivity (as indicated by inhibition studies), however, was present in the only 2 of the 23 LKM1 seropositive HCV patients, who possessed the HLA allotype B51. Our results indicate that in HCV infected patients virus/self cross-reactivity is dependent on a specific immunogenetic background, a finding awaiting confirmation by studies in larger series of patients.

Elevated serum levels of macrophage-derived cytokines precede and accompany the onset of IDDM

To determine whether cytokines could have a role in the development of insulin-dependent diabetes mellitus (IDDM), we measured serum levels of cytokines derived from T helper 1 (interleukin-2 and interferon-gamma), T helper 2 (interleukin-4 and interleukin-10) lymphocytes and macrophages (tumour necrosis factor-alpha, interleukin-1 alpha and interleukin-1 beta) in patients before and after the onset of IDDM. Recently diagnosed IDDM patients had significantly higher levels of interleukin-2, interferon-gamma, tumour necrosis factor-alpha and interleukin-1 alpha than patients with either long-standing IDDM, non-insulin-dependent diabetes (NIDDM), Graves' disease, or control subjects (p < 0.05 for all). Compared with control subjects, patients with long-standing IDDM and those with NIDDM had higher interleukin-2 and tumour necrosis factor-alpha levels (p < 0.01 for all). Interleukin-4 and interleukin-10 were detectable in sera of patients with Graves' disease only, while interleukin-1 beta was not detectable in the serum of any control or test subject. To investigate whether high cytokine levels precede the onset of IDDM, we studied 28 non-diabetic identical co-twins of patients with IDDM, followed-up prospectively for up to 6 years after the diagnosis of the index. Levels of tumour necrosis factor-alpha and interleukin-1 alpha were elevated above the normal range more frequently in the eight twins who developed diabetes than in those 20 who did not (p < 0.005). Analysis of T helper 1 and T helper 2 profiles of the twin groups did not reveal a clear difference between prediabetic twins and twins remaining non-diabetic. These results support the notion that T helper 1 lymphocytes may play a role in the development of IDDM. This is associated with release of macrophage-derived cytokines, which is also a feature of the prediabetic period. The lack of evidence of a dominant T helper 1 profile of cytokine release before diabetes onset suggests that additional events, activating this arm of the cellular immune response, are required in the immediate prediabetic period.

Pathogenesis of insulin-dependent diabetes: a role for activated T lymphocytes

Expression of HLA DR antigens on T lymphocytes indicates that these cells are actively involved in an immune response. Raised levels of activated T lymphocytes were found in 14 of 15 recently diagnosed but in only 7 of 28 long-standing insulin-dependent diabetics. 9 of the recently diagnosed patients retested 6 months later still had high levels of activated T lymphocytes. Even long-standing insulin-dependent diabetics had significantly higher levels of activated T lymphocytes than non-insulin-dependent diabetics and healthy controls. 5 of 7 unaffected co-twins of recently diagnosed insulin-dependent diabetics had high levels of activated T cells; this increase persisted in 2 retested 6 months later, when mildly impaired glucose tolerance had developed. These results confirm that there is an active cellular immune reaction in newly diagnosed insulin-dependent diabetics which may precede the disease and persist for at least 6 months after its appearance.

Primary and secondary liver/kidney microsomal autoantibody response following infection with hepatitis C virus

Liver/kidney microsomal autoantibody type 1 (LKM-1), which characterizes a subtype of autoimmune hepatitis, is also found in some patients with chronic hepatitis C virus (HCV) infection. Whether HCV and LKM-1 are accidentally or causally related is unknown. This case report describes a child who became infected by HCV after liver transplantation for end-stage liver disease caused by alpha 1-antitrypsin deficiency. LKM-1 was detected by immunofluorescence, anti-microsomal reactivity by Western blotting, anti-HCV and anti-GOR by immunoenzymatic assays, and HCV RNA by polymerase chain reaction. Two weeks after HCV infection, immunoglobulin (Ig) M LKM-1 appeared, followed by IgG1 LKM-1, with titers increasing to 1/2560; antibodies to a 50-kilodalton liver microsomal protein appeared 2 months later. Sera from day 1 posttransplant became positive for HCV RNA. HCV RNA was also detected in a liver biopsy specimen obtained 3 months after surgery. The patient did not produce anti-HCV and anti-GOR antibodies throughout the study and had no histological evidence of hepatitis. The temporal relationship between HCV infection and LKM-1 production suggests that HCV may trigger a primary autoimmune response. The lack of liver damage attributable to autoimmunity or viral infection may be caused by immunosuppression.