Frequency and significance of antibodies to actin in type 1 autoimmune hepatitis

Antibodies to actin have been proposed as diagnostic markers for type 1 autoimmune hepatitis. Our aims were to determine 1) if testing for antibodies to actin is superior to testing for smooth muscle antibodies (SMA); 2) if these antibodies identify patients with distinctive clinical features; and 3) if the production of antibodies to actin is associated with genetic risk factors for autoimmune hepatitis. Sera from 99 patients with type 1 autoimmune hepatitis were tested. The frequencies of HLA B8, DR3, DR4, and A1-B8-DR3 in patient subsets were compared with those in 80 normal subjects. Seventy-three patients (74%) had antibodies to actin. Antibodies to actin were found more commonly in patients with SMA than in patients without them (86% vs. 7%, P < .0001). Screening only for antibodies to actin and antinuclear antibodies (ANA) failed to establish the diagnosis of autoimmune hepatitis in 5 patients. Patients with antibodies to actin were younger than seronegative patients. They were also more commonly DR3-positive than normal subjects and more frequently B8-positive than patients with non-actin-associated SMA (49% vs. 0%, P = .004). Only patients with antibodies to actin died of liver failure (6% vs. 0%), and 10 of 11 patients requiring liver transplantation were seropositive for these antibodies. Indeed, death and liver transplantation occurred more frequently in these patients than in actin-negative patients with ANA (19% vs. 0%, P = .03). We conclude that routine screening for antibodies to actin may miss patients with type 1 autoimmune hepatitis. Antibodies to actin are associated with HLA B8 and DR3, and they identify patients with a poor prognosis.

Impact of international autoimmune hepatitis group scoring system in definition of autoimmune hepatitis. An Italian experience

We have reclassified 110 patients with autoantibody-positive cryptogenic chronic hepatitis according tot he aggregate scoring system proposed by the International Autoimmune Hepatitis Group for signs of hepatitis C virus (HCV) infection and the newly proposed terminology of "unclassified" chronic hepatitis. Anti-HCV and HCV viremia were assessed by second-generation assays and reverse transcription-polymerase chain reaction. Immunomorphological and immunochemical characterizations of antinuclear, smooth, muscle, liver-kidney microsomal type 1, and liver cytosol type 1 autoantibodies were also performed. All 45 anti-HCV negative patients fulfilled the score criteria for the diagnosis of "definite" or "probable" autoimmune hepatitis (AIH). Eight anti-HCV-positive cases reached the score of "probable" AIH, whereas the remaining 57 cases were diagnosed as unclassified chronic hepatitis. The scoring system allows the correct identification of all autoimmune cases without HCV infection. Autoimmune hepatitis runs a more severe disease course than unclassified chronic hepatitis, whose clinical and histological features are similar to those of autoantibody-negative chronic hepatitis C.

Detection of anti-liver cytosol antibody type 1 (anti-LC1) by immunodiffusion, counterimmunoelectrophoresis and immunoblotting: comparison of different techniques

Liver cytosol specific antibody type 1 (anti-LC1) was first described in a proportion of patients with liver/kidney microsomal antibody type 1 (anti-LKM1)-positive autoimmune hepatitis (AIH) and is routinely evaluated by immunodiffusion (ID). Using human liver cytosol as the source of antigen, we have used ID, counterimmunoelectrophoresis (CIE) and immunoblotting (IB), to test sera from 167 patients with documented chronic liver diseases of different etiology. 15 patients had antinuclear antibody (ANA) and/or smooth muscle antibody (SMA)-positive AIH, 13 had anti-LKM1-positive AIH, four had ANA/SMA/anti-LKM1-negative AIH, 76 had anti-LKM1-positive hepatitis C (recently renamed unclassified chronic hepatitis-UCH), 40 had chronic hepatitis C, 15 had chronic hepatitis B, and 4 had chronic hepatitis D. A precipitin line of identity with an anti-LC1 reference serum was detected both by ID and CIE in 16 patients: six with anti-LKM1-positive 'definite' AIH, four with ANA/SMA/anti-LKM1-negative 'definite' AIH, and six with anti-LKM1-positive UCH. By IB, 14 out of the 16 anti-LC1-positive sera (87.5%) reacted with a 58 kDa human liver cytosolic polypeptide, whereas three out of 16 (19%) recognised an additional 60 kDa band. Compared to ID, CIE is more economical in terms of both time and reagents and provides more clear-cut results. The 58 kDa reactivity by IB was detectable in nearly all CIE/ID anti-LC1-positive patients, was not found among CIE/ID anti-LC1-negative patients. In conclusion, CIE is the ideal screening test for the detection of anti-LC1, an autoantibody that can be regarded as an additional serological marker of AIH and is especially useful in ANA/SMA/anti-LKM1 negative cases.

Liver cytosolic 1 antigen-antibody system in type 2 autoimmune hepatitis and hepatitis C virus infection

Within the multiform liver/kidney microsomal (LKM) family, a subgroup of sera that reacts with a liver cytosolic (LC) protein has been isolated and the new antigen-antibody system is called LC1. Unlike LKM antibody type 1 (anti-LKM1), anti-LC1 is said to be unrelated to hepatitis C virus (HCV) infection and has therefore been proposed as a marker of 'true' autoimmune hepatitis type 2. Altogether 100 LKM1 positive sera were tested by immunodiffusion (ID). Twenty five gave a precipitation line with human liver cytosol; 17 of the 25 also reacted with rat liver cytosol. Thirteen of the 25 sera were anti-HCV positive by second generation ELISA: anti-HCV positive patients were significantly older (p < 0.001) and tended to have less active disease. No difference in anti-LC1 titre or ID immunoreactivity was found between anti-LC1/anti-HCV positive and anti-LC1/anti-HCV negative cases. In Western blotting experiments, 14 of 24 ID positive sera recognised a 58 kD protein of the human cytosolic fraction and 11 gave a similar reactivity when tested with human microsomes, suggesting the presence of the LC1 target antigen also in the microsomal preparation. Western blotting reactivity was similar for both anti-HCV positive and negative sera. These data confirm the existence of the LC1 antigen-antibody system that partially overlaps with LKM1, and that it is an additional marker of juvenile autoimmune hepatitis type 2. It does not, however, discriminate between patients with and without HCV infection.

Hepatocellular expression of HLA-A, B, C molecules predicts primary response to interferon in patients with chronic hepatitis C

Primary response rate to alpha-interferon (IFN) is about 50% in patients with chronic hepatitis C. Criteria for predicting a positive primary response are lacking. HLA-A,B,C molecule expression is known to be stimulated by viral infections. In 36 consecutive interferon-treated anti-HCV positive patients with an available frozen liver biopsy sample, the predictive value of liver HLA-A,B,C expression, and of histologic, clinical, and biochemical parameters was evaluated. Response to treatment was defined by normalization of transaminases, and disappearance of serum HCV-RNA within 3 months. According to these criteria, 17 patients were classified as nonresponders and 19 were classified as responders. The pattern of HLA-A,B,C hepatocellular positivity varied from normal (negative or occasional faint staining of hepatocellular membranes) to diffuse, strong "honeycomb" positivity. The highest scores of positivity were found in nonresponder patients. The discriminant capacity of HLA-A,B,C scores of positivity was compared with clinical, biochemical and histologic parameters by discriminant analysis. HLA-A,B,C expression was found to be the main discriminant parameter, in addition to alkaline phosphate (ALP) and gamma-glutamyl-transpeptidase (GGT) which added little additional information. The higher hepatocellular expression of class I MHC molecules in nonresponder cases may reflect a different viral effect on hepatocytes, which is induced by different HCV genotypes or levels of viremia. From a clinical point of view, the pretreatment HLA-A,B,C pattern of positivity represents a powerful tool in the selection of patients for interferon treatment.

Interferon therapy in liver/kidney microsomal antibody type 1-positive patients with chronic hepatitis C

The association between liver/kidney microsomal antibody type 1 and adult cases of hepatitis C virus-related chronic liver disease has been firmly established. In the presence of both markers, evidence of autoimmunity (liver/kidney microsomal antibody type 1) and actual viremia (serum HCV RNA), the therapeutic dilemma arises between steroids, which are beneficial to autoimmune but deleterious to viral diseases, and interferon-alpha, which may exacerbate an autoimmune disorder. Six patients with liver/kidney microsomal antibody type 1 and serum HCV RNA were given interferon-alpha: three showed a response pattern similar to that observed in autoantibody-negative chronic hepatitis C cases; the other three developed a sharp transaminase peak, which was not followed by HCV RNA clearance. Considering the brisk flare-up of liver cell necrosis, interferon-alpha treatment proved to be dangerous in the above three liver/kidney microsomal antibody type 1/HCV RNA positive cases. Subsequent steroid administration reduced alanine aminotransferase peaks, but may be harmful in viral infections. Therapeutic alternatives are needed: they will probably include pure antivirals (exerting no immunostimulatory effects) with or without immunosuppressive drugs.

Testing for hepatitis C virus sequences in peripheral blood mononuclear cells of patients with chronic hepatitis C in the absence of serum hepatitis C virus RNA

Hepatitis C virus (HCV) is able to replicate in peripheral blood mononuclear cells (PBMC) of HCV-infected patients. Few data are available on PBMC testing for HCV RNA in serum HCV RNA negative patients, positive for anti-HCV and with histological evidence of chronic hepatitis. Twenty such patients were studied; of these, 11 were tested during interferon alpha (IFN) treatment, at the time of serum HCV RNA clearance and ALT normalisation: only one was found to be positive for HCV sequences in PBMC. Within 3 months of IFN withdrawal all 11 patients relapsed with high ALT and recurrence of serum HCV RNA. Of nine serum HCV RNA negative patients with chronic hepatitis C who were not receiving IFN when tested (four untreated patients and five patients who had already completed IFN schedule), PBMC HCV RNA was detected in four. Evidence of active HCV replication (presence of the minus strand genome) in PBMC was also observed in two cases. Thus, five of the 20 patients without detectable serum HCV RNA turned out to be carriers of HCV sequences in PBMC. These data indicate that: 1. PBMC are an extrahepatic replication site of HCV; this is true also in the absence of serum HCV RNA; 2. the role of PBMC as a "viral reservoir" after IFN-induced serum HCV RNA clearance is questioned; 3. the absence of both serum and PBMC HCV RNA in patients under IFN is not predictive of sustained viral loss; 4. testing for PBMC viral sequences might enhance the chances of detecting HCV infection.

Increased risk of hepatocellular carcinoma development in patients with cirrhosis and with high hepatocellular proliferation

The immunohistochemical determination of the accessory protein of DNA-polymerase delta (PCNA), a marker of an early S-phase of the cell cycle, was used to evaluate cell proliferation retrospectively in formalin-fixed, paraffin-embedded liver biopsy sections in a group of patients with cirrhosis of similar age and duration of follow up, and with no evidence of hepatocellular carcinoma (41), including 17 patients with and 24 without hepatocellular carcinoma appearance during follow up. Proliferation was expressed as total (PCNA-TOT) and strongly (PCNA-STRO) positive nuclei per 1000 hepatocytes. The presence of dysplasia was also recorded. Histological findings and biochemical data, at the time of liver biopsy, were compared in the two groups. While total PCNA positivities were not significantly different in the two groups, strong reactivity was significantly higher in patients who eventually developed hepato-cellular carcinoma (median 0.7 vs 2.6). Univariate analysis of histological and biochemical data at the time of biopsy, followed by a stepwise regression study, showed that the significant parameters for a time-dependent disease-free state were, in decreasing order: cholesterol, PCNA-STRO, PCNA-TOT and alpha foeto-protein. Other clinical, biochemical and histological parameters, including dysplasia, provided no further information. From these data, hepatocellular proliferation can be evaluated in patients with cirrhosis with a currently available technique. Patients with high cell proliferation are at increased risk of developing hepatocellular carcinoma and may require differentiated follow up.

Abdominal lymphadenopathy detected by ultrasonography in HIV-1 infection: prevalence and significance

By using abdominal ultrasonography (UlS), deep nodes were detected in 41 of 85 (48%) HIV-1 positive subjects, most of them heroin addicts, but in none of 85 healthy HIV-negative controls. Computerized tomography, performed in 10 cases of lymphadenopathy, invariably confirmed the UlS findings. Prevalence [asymptomatic carriers: 8/15 (53%); PGL patients: 8/18 (44%); ARC: 13/27 (48%); AIDS: 12/25 (48%)], number, size, and site of deep nodes were comparable among the different CDC groups. No correlation was found between abdominal and superficial lymphadenopathy. Median serum concentrations of gammaglobulins (g/dl) and IgG (mg/dl) were higher in patients with than without deep nodes (2.25 vs 1.87 and 2540 vs 1900, respectively) (p < 0.01) as well as in cases with than without superficial nodes (2.15 vs 1.80 and 2340 vs 1941, respectively) (p < 0.05). Abdominal lymphadenopathy occurred during all stages of HIV infection even in asymptomatic carriers: this should be considered in the differential diagnosis of UlS-detected deep nodes. Enlargement of either deep or superficial nodes seems to reflect a state of polyclonal B cell activation.

Serum autoantibodies and the diagnosis of type-1 autoimmune hepatitis in Italy: a reappraisal at the light of hepatitis C virus infection

Antinuclear antibodies with the homogeneous pattern (ANA-H) and smooth muscle antibodies with antiactin specificity (SMA-AA) are regarded as the serum markers of type-1 autoimmune chronic hepatitis. Their diagnostic relevance, however, has been questioned recently after the detection of signs of hepatitis C virus infection in autoimmune chronic hepatitis patients. To further evaluate this point, antihepatitis C virus antibodies were sought by two second generation assays (ELISA 2 and RIBA 2) in 100 Italian patients with chronic liver disease of unknown aetiology, including 46 with (autoimmune chronic hepatitis) and 54 without the above antibodies (cryptogenic). By ELISA 2, antihepatitis C virus, although significantly prevalent in cryptogenic (83%), were found also in a substantial proportion of autoimmune chronic hepatitis patients (46%) (p < 0.0001), their occurrence was confirmed by RIBA 2 in almost all cases (96% and 86%, respectively). Autoimmune patients with either ANA-H or SMA-AA exhibited similar antihepatitis C virus prevalences (59% and 52%, respectively); by contrast, the eight cases positive for both the autoantibodies were consistently antihepatitis C virus negative. These findings confirm that in countries with high hepatitis C virus circulation (like Italy) an overlap between autoimmune chronic hepatitis and hepatitis C virus infection, reflected by 'true' antihepatitis C virus antibodies, does occur. The detection of ANA-H or SMA-AA, in fact, identifies chronic liver disease patients with a relatively low prevalence of antihepatitis C virus, but does not exclude hepatitis C virus infection. Positive findings for both ANA-H and SMA-AA, however, is an appropriate marker for hepatitis C virus free 'primary' autoimmune chronic hepatitis.

Demonstration of peptide-specific and cross-reactive epitopes in proteins reacting with antimitochondrial antibodies of primary biliary cirrhosis

Recently the main targets of antimitochondrial antibodies (AMA) of primary biliary cirrhosis have been identified as parts of three related mitochondrial multienzyme complexes, namely pyruvate dehydrogenase (PDH), branched chain alpha-ketoacid dehydrogenase (BKDH) and alpha-ketoglutarate dehydrogenase (alpha-KGDH). Usually AMA-positive PBC serum samples show reactivity to more than one of these, raising the question whether they are exclusively different antibodies or are, at least in part, the result of cross-reactive specificities. With Western immunoblotting, four antigens with molecular masses of 74, 52, 51 and 43 kDa, are recognized by PBC sera. In this study, using affinity purified antibodies from mitochondrial proteins immobilized on nitrocellulose blots, we demonstrate the presence of peptide-specific and cross-reactive epitopes in some targets. In particular, at least three different epitopes present in the 74-kDa protein (presumed to by PDH-E2) are also present in the 51-kDa protein (probably PDH-X), and two in the 52-kDa peptide (possibly BCKDH-E2). Moreover, the 43-kDa mitochondrial protein (the identity of which is more problematic) has three epitopes. One of these is also present in the 74-, 52- and 51-kDa proteins, a second in the 74- and 51-kDa, and a third seems to be peptide-specific. These results show that different sera with the same immunoblotting pattern of reactivity can have antibodies with different antigenic specificities and, conversely, that the same specificity can be responsible for more than one band.

Hepatitis C viraemia in adults with type 2 autoimmune hepatitis

Sera from 14 patients with type 2 autoimmune hepatitis (anti-LKM1 positive) were investigated for evidence of hepatitis C virus (HCV) infection. Antibodies to HCV were detected in 13 patients by both commercial and "in-house" ELISAs and also by a second generation recombinant immunoblot assay. Nine of the 13 (69%) anti-HCV positive patients were shown to be viraemic by a polymerase chain reaction-based assay for serum HCV RNA. Neither anti-HCV nor serum HCV RNA were detected in any of 6 controls with primary biliary cirrhosis or in 39 healthy blood donors. These findings strongly suggest a role for HCV in the pathogenesis of type 2 autoimmune hepatitis.

IgA antiendomysial antibody test. A step forward in celiac disease screening

Serum IgA antiendomysial antibodies (EmA) were found in 61 (87%) of 70 adults and children with untreated celiac disease, whereas IgA antigliadin antibodies (AGA) and IgA R1-antireticulin antibodies (R1-ARA) were positive in 71% and 47%, respectively, of the same patients. Two of the nine untreated celiacs negative for IgA EmA showed positivity for IgA AGA. While IgA AGA and R1-ARA disappeared in all the celiacs tested one year after gluten-free diet, IgA EmA persisted at low titer in seven (18%) of these 38 subjects, although the jejunal biopsy showed a complete regrowth of jejunal villi. All the disease control patients as well as the blood donors tested were always negative for the three IgA antibodies. Our results state that the search for both IgA EmA and AGA gives the best results in the screening of celiac disease, since the positivity for at least one of these two antibodies allows identification with a 100% specificity of the 90% of untreated celiac patients.

Anti-nuclear antibodies of primary biliary cirrhosis recognize 78-92-kD and 96-100-kD proteins of nuclear bodies

The specificities of anti-nuclear antibodies (ANA) reacting with multiple nuclear dots (MND-ANA) present in about 15% primary biliary cirrhosis sera were studied by Western blot analysis with nuclear fractions from a human cell line. Reactivity with two broad bands of 78-92 kD and 96-100 kD of the insoluble fraction was present exclusively in MND-ANA-positive sera. Antibodies eluted from these proteins specifically retained the immunofluorescence reactivity of MND-ANA. Immunomorphological analysis by a pre-embedding technique revealed that the antibody specifically binds to nuclear regions resembling in size and number nuclear bodies. Since these structures are absent in immature rate endometrial cell and can be induced by diethylstilbestrol, we tested MND-ANA by immunofluorescence on cryostat sections of uteri from hormone-treated and untreated immature rats. A strong reaction of nuclear dots was observed predominantly in endometrial cells of hormone treated rats. We thus conclude that MND-ANA present in primary biliary cirrhosis sera are directed against 78-92-kD and 96-100-kD nuclear proteins located in nuclear bodies.

Serum non-organ specific autoantibodies in human immunodeficiency virus 1 infection

Serum samples from 66 seropositive subjects (56 with a history of intravenous drug abuse), including asymptomatic carriers and patients with persistent generalised lymphadenopathy (PGL), AIDS related complex (ARC), and AIDS, were tested by indirect immunofluorescence on rat tissue sections and HEp-2 cells for the presence of antibodies to nuclei, smooth muscle, intermediate filaments (anti-IMF) and microfilaments (anti-MF). Counterimmunoelectrophoresis was also used to detect antibodies to extractable nuclear antigens. Smooth muscle antibodies with the V pattern or antinuclear antibodies, mainly of the speckled type, or anti-IMF, occurred in 35 cases, being widely distributed in all groups. Such an autoantibody response resembles the "viral" autoimmunity described in various infectious diseases and in particular that of non-A, non-B post-transfusion hepatitis. Autoantibodies may be of some prognostic relevance, as the prevalence of smooth muscle antibodies V increased as the disease progressed (asymptomatic carriers 20%, those with PGL 29%, those with ARC 47%, and those with AIDS 63%. In the PGL group autoantibody positivity correlated with the presence of skin anergy. The fact that autoantibodies were more frequently detected in patients with circulating immune complexes suggests that these can contain autoantibodies and the corresponding autoantigens.