Hepatitis C virus (HCV) genotype, tissue HCV antigens, hepatocellular expression of HLA-A,B,C, and intercellular adhesion-1 molecules. Clues to pathogenesis of hepatocellular damage and response to interferon treatment in patients with chronic hepatitis C.

To obtain information on the mechanisms of hepatocellular damage and the determinants of response to interferon, hepatitis C virus (HCV) genotype, tissue HCV antigens, hepatocellular expression of HLA-A,B,C and intercellular adhesion-1 molecules, and the number of lobular T lymphocytes were studied in 38 anti-HCV-positive patients. 14 patients did not show a primary response to interferon treatment. HCV genotype 1b was detected in 11 of them. They displayed higher scores of HCV-positive hepatocytes, HLA-A,B,C, and ICAM-1 molecules expression than with the responders. HCV-infected hepatocytes maintained the capacity to express HLA-A,B,C and ICAM-1 molecules. CD8-positive T cells in contact with infected hepatocytes and Councilman-like bodies were observed. A significant correlation was found between the number of lobular CD8-positive T cells and alanine amino transferase levels. No differences were observed in clinical, biochemical, and histological features between patients with high and low number of hepatocytes containing HCV antigens. These data suggest a prominent role of T cell-mediated cytotoxicity in the genesis of hepatocellular damage. The high expression of interferon-inducible antigens like HLA-A,B,C molecules suggests the presence of strong activation of the interferon system possibly related to high HCV replication in nonresponder patients infected with genotype 1b.

Antibodies to SS-A/Ro-52kD and centromere in autoimmune liver disease: a clue to diagnosis and prognosis of primary biliary cirrhosis.

BACKGROUND: Primary biliary cirrhosis (PBC) may be associated with various rheumatological disorders. AIM: To investigate the frequency and significance of 'rheumatological' antinuclear antibodies in the field of autoimmune chronic liver disease, with special regard to PBC. METHODS: We studied 105 patients with PBC, 162 autoimmune liver disease controls (type 1 and 2 autoimmune hepatitis, primary sclerosing cholangitis), 30 systemic lupus erythematosus and 50 blood donors. Sera were tested for the presence of antibodies to extractable nuclear antigens (anti-ENA) by counterimmunoelectrophoresis, enzyme-linked and immunoblot (IB) assay, and for the presence of anti-centromere antibodies (ACA) by indirect immunofluorescence on HEp-2 cells and IB. RESULTS: The overall prevalence of IB-detected anti-ENA in PBC (30%) was higher than in type 1 autoimmune hepatitis (2.5%, P < 0.0001), type 2 autoimmune hepatitis (0%, P < 0.0001) and primary sclerosing cholangitis (11.5%, P = 0.006) and lower than in systemic lupus erythematosus (53%, P = 0.03). The most frequent anti-ENA reactivity in PBC was anti-SSA/Ro-52kD (28%). ACA were detected by IB in 21% PBC patients and never in the other subjects (P < 0.0001). Anti-SS-A/Ro/52kD positive PBC patients had at the time of diagnosis a more advanced histological stage (P = 0.01) and higher serum levels of bilirubin (P = 0.01) and IgM (P = 0.03) compared with negative ones. CONCLUSIONS: In the autoimmune liver disease setting, anti-SS-A/Ro-52kD and ACA have a high specificity for PBC and can thus be of diagnostic relevance in anti-mitochondrial antibodies negative cases. If confirmed in further studies with adequate follow-up, anti-SS-A/Ro-52kD antibodies might identify PBC patients with a more advanced and active disease.

Extrahepatic manifestations of Hepatitis C Virus infection: a general overview and guidelines for a clinical approach.

Hepatitis C Virus is associated with a wide series of extrahepatic manifestations. Based on available data the link between the virus and some of these extrahepatic diseases is only suggested and needs further confirmation. Hepatitis C Virus-related lymphoproliferative disorders, whose prototype is mixed cryoglobulinaemia, represent the most closely related extrahepatic manifestations of Hepatitis C Virus. Other Hepatitis C Virus-associated disorders include nephropathies, thyreopathies, sicca syndrome, idiopathic pulmonary fibrosis, porphyria cutanea tarda, lichen planus, diabetes, chronic polyarthritis, cardiopathy and atherosclerosis. A pathogenetic link between Hepatitis C Virus and some extrahepatic manifestations was confirmed by their responsiveness to antiviral therapy, which is now deemed the first therapeutic option to consider. By contrast, there are diseases where treatment with interferon was ineffective or dangerous. The aim of the present paper is to outline the most recent evidence concerning extrahepatic disorders that are possibly associated with Hepatitis C Virus infection. Special emphasis will be given to discussion of the most appropriate clinical approaches to be adopted in order to diagnose, treat (possibly prevent) and follow-up extrahepathic diseases in patients with Hepatitis C Virus infection.

Antinuclear antibodies giving the 'multiple nuclear dots' or the 'rim-like/membranous' patterns: diagnostic accuracy for primary biliary cirrhosis.

BACKGROUND: Serum antinuclear antibodies giving the 'multiple nuclear dots' or the 'rim-like/membranous' patterns are frequently detected by indirect immunofluorescence on HEp-2 cells in patients with primary biliary cirrhosis. AIM: To assess the accuracy of multiple nuclear dot and rim-like/membranous antinuclear antibodies for the diagnosis of primary biliary cirrhosis. METHODS: Sera from 4371 consecutive patients referred to our laboratory were analysed under code for antinuclear antibodies testing by indirect immunofluorescence on HEp-2 cells. RESULTS: Review of the clinical records of the 4371 patients allowed identification of 101 patients with antimitochondrial antibody-positive primary biliary cirrhosis and 22 with antimitochondrial antibody-negative variant. Multiple nuclear dot and/or rim-like/membranous patterns were found in 59 (1.3%) of the 4371 patients: 31 antimitochondrial antibody-positive primary biliary cirrhosis, 17 antimitochondrial antibody-negative primary biliary cirrhosis and 11 non-primary biliary cirrhosis. The specificity for primary biliary cirrhosis of both the antinuclear antibodies pattern was 99%. Positive predictive value and likelihood ratio for a positive test were 86% (95% CI: 72.7-94) and 221 (95% CI: 91.7-544) for multiple nuclear dot, 79% (95% CI: 62.2-90.1) and 132 (95% CI: 56.8-312.7) for rim-like/membranous, respectively. CONCLUSIONS: Multiple nuclear dot and rim-like/membranous antinuclear antibodies are rare findings. Their positivity strongly suggests the diagnosis of primary biliary cirrhosis, irrespective of antimitochondrial antibody status. The high specificity for primary biliary cirrhosis makes them a useful diagnostic tool especially in antimitochondrial antibody-negative patients.

Antibodies to filamentous actin (F-actin) in type 1 autoimmune hepatitis.

AIMS: To evaluate the diagnostic significance of anti-filamentous actin antibodies (A-FAA) assessed with a commercial ELISA in comparison with immunofluorescence reactivity and patterns of anti-smooth muscle antibodies (SMA); and to correlate A-FAA positivity with clinical, immunogenetic, laboratory, and histological features in patients with autoimmune hepatitis type 1 (AIH-1). METHODS: We studied 78 consecutive untreated AIH-1 patients and 160 controls: 22 with autoimmune hepatitis type 2 (AIH-2), 51 with hepatitis C, 17 with coeliac disease (CD), 20 with primary biliary cirrhosis (PBC) and 50 blood donors. SMA was evaluated by indirect immunofluorescence (IIF) on frozen sections of rat tissues, and A-FAA with a modified commercial ELISA. RESULTS: SMA was detected by IIF in 61 (78%) of 78 AIH-1 patients, of whom 47 (60%) had the SMA-T/G and 14 (18%) the SMA-V pattern. Of the pathological controls, 32 (20%) had the SMA-V pattern (25 with hepatitis C, 2 with AIH-2, 2 with PBC, 3 with CD). A-FAA were present in 55 AIH-1 patients (70.5%; 46 with SMA-T/G, 7 with SMA-V, and 2 SMA-negative), and in 10 controls (6%), of whom five had hepatitis C, two AIH-2, two PBC and one CD. The association between A-FAA and the SMA-T/G pattern was statistically significant (p<0.0001). A-FAA levels were higher in SMA-T/G positive than SMA-V positive AIH-1 patients and controls (p<0.0001). A-FAA positivity was significantly associated with higher gamma-globulin and IgG levels, but did not correlate with other considered parameters. CONCLUSION: The modified A-FAA ELISA strictly correlates with the SMA-T/G pattern and is a reliable and operator independent assay for AIH-1. Detection of A-FAA, even if devoid of prognostic relevance, may be useful when interpretative doubts of standard IIF arise.

Anti-ganglioside antibodies in coeliac disease with neurological disorders.

BACKGROUND: Anti-ganglioside antibodies have been described in sera of coeliac patients with peripheral neuropathy and cerebellar ataxia. AIMS: To investigate the correlation between anti-ganglioside antibodies and neurological involvement in coeliac disease before and after gluten-free diet. PATIENTS AND METHODS: Twenty-two untreated coeliac patients with neurological dysfunction and 30 untreated coeliacs without neurological dysfunction, 20 patients with neurological disorders, 50 autoimmune disease and 20 blood donors were tested for anti-GM1, anti-GD1b and anti-GQ1b IgG and IgM antibodies by enzyme-linked immunosorbent assay. RESULTS: IgG antibodies to at least one of the three antigens tested were positive in 64% of coeliac patients with neurological symptoms compared to 30% of coeliacs without neurological dysfunction (P=0.02), 50% of patients with neurological disorders (P=ns), 20% with autoimmune diseases (P=0.003) and none of blood donors (P=0.0001). A strict gluten-free diet determined anti-ganglioside antibody disappearance in about half of coeliacs. CONCLUSIONS: A significant correlation between anti-ganglioside antibodies and neurological disorders in patients with an underlying coeliac disease has been found. Anti-ganglioside antibodies may represent a new immunological marker to identify neurological impairment in patients with coeliac disease.

Autoimmune enteropathy and rheumatoid arthritis: a new association in the field of autoimmunity.

We report the case of a 35-year-old woman with a diagnosis of coeliac disease at the age of 32 due to a severe malabsorption and flat mucosa without endomysial and tissue transglutaminase antibodies. The lack of clinical and histological improvement after 1 year of a gluten-free diet led to a diagnosis of refractory sprue. She had a good clinical response to steroids that were stopped after 3 months when she became pregnant. After delivery, she again started to complain of malabsorption with arthritis. Positivity for enterocyte autoantibodies together with a flat mucosa persistence allowed to identify a condition of autoimmune enteropathy; moreover, a rheumatological assessment gave evidence of an associated rheumatoid arthritis. Treatment by steroids and methotrexate brought to the remission of intestinal and articular symptoms together with an improvement of duodenal histology. This is the first description of an autoimmune enteropathy associated with rheumatoid arthritis. Autoimmune enteropathy should be always ruled out in patients with a villous atrophy unresponsive to a gluten-free diet, autoimmune manifestations and negativity of coeliac disease markers.

Clinical features of type 1 autoimmune hepatitis in elderly Italian patients.

BACKGROUND: The usual onset of type 1 autoimmune hepatitis occurs at puberty or around menopause, whereas disease presentation in the advanced age is less often reported. AIM: To assess the clinical, immunological and histological features of Type 1 autoimmune hepatitis in elderly Italian patients. METHODS: We assessed, at diagnosis, the clinical and immunological features of 76 consecutive Italian patients with type 1 autoimmune hepatitis, focusing particularly on a subgroup of 20 patients presenting at > or = 65 years (females 95%, median age 72 years, range 65-82). RESULTS: In comparison with the younger group, at the time of autoimmune hepatitis diagnosis, elderly Italian patients are more often asymptomatic (25% vs. 7%; P = 0.04), are more frequently positive for antinuclear autoantibodies (95% vs. 52%; P = 0.0004) and HLA-DR4 (45% vs. 18%; P = 0.03); among the extra-hepatic manifestations, autoimmune thyroid disorders are prevalent in the elderly group (25% vs. 5%; P = 0.02). However, no difference was observed in the histological/biochemical expression of the liver disease and response to immunosuppression. CONCLUSIONS: In elderly Italian patients, autoimmune hepatitis has typical serological and genetic characteristics, is more frequently asymptomatic, although prognosis and response to therapy is similar to that of younger patients. As a concomitant autoimmune thyroid disorder is common, autoimmune hepatitis should be suspected and investigated in elderly patients with autoimmune thyroid disorder and abnormal liver function tests.

Hepatic steatosis in chronic hepatitis C: impact on response to anti-viral treatment with peg-interferon and ribavirin.

BACKGROUND: There is increasing evidence that hepatic steatosis contributes to the progression of liver fibrosis, whereas its impact on the efficacy of anti-viral treatment is still under investigation. AIM: To evaluate the effect of steatosis on the outcome of combined anti-viral treatment. METHODS: We studied 102 consecutive naive patients with chronic hepatitis C receiving combined anti-viral therapy (peg-interferon alpha-2b and ribavirin). RESULTS: Fifty (49%) of 102 patients had evidence of hepatic steatosis (29 grade 1, 16 grade 2 and 5 grade 3). Sustained virological response was similar in patients with and without steatosis (58% vs. 56%); moreover, the grade of steatosis did not affect the rate of sustained virological response (grade 1: 58%, grade 2: 56% and grade 3: 60%). Patients with steatosis had significantly higher serum levels of aspartate transaminase, alanine transaminase and gamma-glutamyltransferase (P = 0.007, 0.004 and 0.03, respectively), higher histological activity (P = 0.03), more advanced stage of fibrosis (P = 0.0394) and more often hepatitis C virus genotype 3 (P = 0.04). CONCLUSIONS: Our findings suggest that hepatic steatosis in chronic hepatitis C, irrespective of its grade, is not a negative prognostic factor of response to combined anti-viral therapy, even when the histological and biochemical profile of the disease is more aggressive.

HCV liver infection and liver steatosis: evidence for indirect mechanisms in genotype 3?

BACKGROUND: Hepatitis C virus (HCV) infection is associated with the appearance of liver steatosis. AIM: To search for a correlation between the number of HCV infected hepatocytes and the presence, amount and distribution of steatosis. METHODS: A total of 124 frozen liver biopsies from HCV patients (genotype 3 = 21) were studied. HCV-antigens were detected on frozen liver sections using a four steps immunoperoxidase technique. Steatosis was graded by haematoxilin-eosin counterstaining on a serial section. RESULTS: Steatosis was detected in 82 of 124 (66.1%) patients without differences between different genotypes. Uric acid, body mass index, gammaGT levels significantly correlated with steatosis in non-3 (P < 0.01, P < 0.05, P < 0.01, respectively) but not in genotype 3 patients. HCV-antigens were detected in 95 of 124 (76.6%) cases. A positive correlation between steatosis and the number of infected hepatocytes was observed only in genotype 3 patients (P = 0.06). In most cases the number of cells with steatosis greatly outnumbered that of HCV infected cells. CONCLUSION: We confirm a possible role of the virus in the genesis of steatosis in HCV genotype 3 infected patients; however, as steatosis do not appear to be directly related to the presence of HCV-antigens within single hepatocytes, an indirect, possibly cytokine mediated, mechanism might be operative.

Anti-Saccharomyces cerevisiae and perinuclear anti-neutrophil cytoplasmic antibodies in coeliac disease before and after gluten-free diet.

BACKGROUND: Anti-Saccharomyces cerevisiae and perinuclear anti-neutrophil cytoplasmic autoantibodies are markers of Crohn's disease and ulcerative colitis respectively. AIM: To determine the prevalence of anti-S. cerevisiae and perinuclear anti-neutrophil cytoplasmic autoantibodies in a large series of coeliac disease patients before and after gluten free diet, and to correlate anti-S. cerevisiae-positivity with intestinal mucosal damage. METHODS: One hundred and five consecutive coeliac disease patients and 141 controls (22 ulcerative colitis, 24 Crohn's disease, 30 primary sclerosing cholangitis, 15 postenteritis syndrome, 50 blood donors) were tested for anti-S. cerevisiae by enzyme-linked immunosorbent assay and for perinuclear anti-neutrophil cytoplasmic autoantibodies by indirect immunofluorescence. RESULTS: In coeliac disease anti-S. cerevisiae (immunoglobulin G and/or immunoglobulin A) were slightly less frequent (59%) than in Crohn's disease (75%, P = 0.16) and significantly more frequent than in ulcerative colitis (27%), primary sclerosing cholangitis (30%), postenteritis syndrome (26%) and blood donors (4%) (P = 0.009, P = 0.0002, P = 0.025, P < 0.0001). No correlation was found between anti-S. cerevisiae and degree of mucosal damage. Perinuclear anti-neutrophil cytoplasmic autoantibodies were detected only in one coeliac. After gluten free diet the disappearance of anti-S. cerevisiae-immunoglobulin A (93%) was more frequent than that of immunoglobulin G (17%, P = 0.0001); perinuclear anti-neutrophil cytoplasmic autoantibodies disappeared in the only coeliac positive at diagnosis. CONCLUSION: More than half of untreated coeliacs are anti-S. cerevisiae-positive irrespective of the severity of mucosal damage. Differently from immunoglobulin A, anti-S. cerevisiae-immunoglobulin G persisted in more than 80% after gluten free diet. The high prevalence of anti-S. cerevisiae in coeliac disease suggests that they may be the effect of a non-specific immune response in course of chronic small bowel disease.

Anti-cyclic citrullinated peptide antibodies in type 1 autoimmune hepatitis.

BACKGROUND: Besides the autoantibodies included in the diagnostic criteria of type 1 autoimmune hepatitis, many other autoantibodies have been described in this condition. Recently, antibodies against cyclic citrullinated peptide have been validated as specific diagnostic and prognostic markers of rheumatoid arthritis. AIM: To assess whether these antibodies are part of the autoantibody repertoire of type 1 autoimmune hepatitis and correlate with rheumatological manifestations. METHODS: Antibodies against cyclic citrullinated peptide were tested by a commercially available enzyme-linked immunosorbent assay. RESULTS: The antibodies were found in 12 of 133 (9%) type 1 autoimmune hepatitis, two of 49 (4%) with primary biliary cirrhosis, one of 80 (1%) with hepatitis C virus-related chronic liver disease and 53 of 89 (60%) with rheumatoid arthritis serum samples. High titres were found only in rheumatoid arthritis and type 1 autoimmune hepatitis. No clinical (in particular rheumatological manifestations), biochemical or immunoserological differences were detectable between antibodies against cyclic citrullinated peptide positive and negative type 1 autoimmune hepatitis sera, with the exception of rheumatoid factor, always negative in the positive ones. CONCLUSIONS: Antibodies against cyclic citrullinated peptide can be detected in a subgroup of patients with type 1 autoimmune hepatitis. They might be part of the wide range of autoantibody production characteristic of this condition and/or, less probably, be predictive of future rheumatoid arthritis development.

The Western immunoblotting pattern of anti-mitochondrial antibodies is independent of the clinical expression of primary biliary cirrhosis.

Anti-mitochondrial antibodies are the serological markers of primary biliary cirrhosis. We analysed the detailed anti-mitochondrial antibodies patterns to see whether the immunological specificities detected at the time of the diagnosis correlate with the histological, clinical and immunological expression of the disease. One hundred and thirty primary biliary cirrhosis patients were studied at the time of presentation/diagnosis. Anti-mitochondrial antibodies reactivity was dissected and evaluated by Western immunoblotting with bovine heart submitochondrial particles as antigenic source. Six different Western immunoblotting patterns have been identified with the following hierarchy: pattern A (anti-PDC-E2+anti-E3BP, 38.5%), pattern B (anti-PDC-E2+anti-E3BP+anti-OGDC-E2, 20.8%), pattern C (anti-PDC-E2+anti-E3BP+anti-BCOADC-E2+anti-OGDC-E2, 13.1%), pattern D (anti-PDC-E2+anti-E3BP+anti-BCOADC-E2, 6.9%), pattern E (anti-BCOADC-E, 6.1%) and pattern F (anti-mitochondrial antibodies negative primary biliary cirrhosis, 14.6%). The different patterns were neither associated with peculiar clinical, biochemical, histological and immunological features nor with the Mayo Risk Score. The anti-mitochondrial antibodies pattern at presentation is independent of the stage of the liver disease; therefore, the Western immunoblotting characterisation of anti-mitochondrial antibodies does not seem to be helpful in identifying the clinical, biochemical or histological expression of primary biliary cirrhosis at the time of the diagnosis.

Association of serum IgA antibodies to milk antigens with severe atherosclerosis.

The presence of antibodies of the IgA class against dietary antigens (bovine IgG (BGG), beta-lactoglobulin, casein, alpha-lactalbumin and xanthine oxidase, chicken ovalbumin and crude gliadin) was checked in the sera of 23 severely atherosclerotic subjects (ATS) and 20 highly selected controls (C). In these subjects an association between serum IgA levels and atherosclerosis had previously been shown. Determinations were performed by a micro-ELISA method and results were expressed as absorbances at 405 nm x 1000. Higher levels of IgA antibodies were found in ATS with respect to C against beta-lactoglobulin (respectively, 113.4 +/- 152.4 (1 SD) vs. 40.0 +/- 34.2; P less than 0.005) and casein (69.8 +/- 35.5 vs. 52.4 +/- 27.5; P less than 0.05). There was no difference in IgG and IgM against these 2 proteins between the 2 groups. Significant differences of prevalence of IgA antibodies were found for the following antigens: beta-lactoglobulin (4 C and 16 ATS over the limit value of 51; P less than 0.002), xanthine oxidase (1 C and 9 ATS over 289; P less than 0.01), BGG (7 C and 17 ATS over 87; P less than 0.02) and casein (5 C and 14 ATS over 60; P less than 0.02). These data suggest an association between anti-milk IgA antibodies and atherosclerosis. Its relevance and significance deserves further investigation.

Immunofluorescent detection of anti-cytoskeleton antibodies using vinblastine-treated mononuclear cells.

A reliable and reproducible immunofluorescence method is described for the detection of anti-cytoskeleton antibodies in human sera, based on the use of vinblastine-treated peripheral blood mononuclear cells as substrate. Three immunofluorescence patterns associated with antibodies to microfilaments, intermediate filaments and microtubules are readily identified.

A microELISA assay to detect anti-liver-specific protein antibodies in the sera of patients with liver diseases.

A microELISA to detect anti-liver-specific protein (LSP) antibodies in human sera is described. Rabbit LSP was used as antigen. Optimal conditions for antigen concentration, serum dilution, substrate incubation time and reproducibility with time were established. The microELISA is specific, as assessed by testing anti-LSP positive sera with another lipoprotein from rabbit plasma (VLDL), although a weak cross-reactivity between LSP and VLDL was observed. The test was applied to patients with HBsAg-positive and -negative chronic active hepatitis (CAH). Ten of 26 (38%) patients were positive for anti-LSP antibodies, in comparison with healthy controls used to determine the threshold of positivity. Such a percentage is comparable with that reported for radioimmunoassay (RIA) procedures.

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.

Anti-actin antibodies: a new test for an old problem.

Smooth muscle antibodies with anti-actin specificity are commonly regarded as markers of autoimmune liver disease. However, there are interpretational problems because different techniques have been used for their identification and therefore the results are difficult to compare. The present paper reports the results of a new method for the identification of anti-actin antibodies (indirect immunofluorescence on cryostat sections of liver from rats chronically injected with phalloidin). The results have been compared with those obtained by four other techniques: demonstration by immunofluorescence of kidney peritubular reactivity (SMAT), of anti-microfilament antibodies (on HEp-2 cells and vinblastine-treated peripheral blood mononuclear cells) and counterimmunoelectrophoresis with purified muscle actin as antigen. The new method proved to be the most sensitive and specific. Furthermore, its reproducibility was found to be high, the interpretation easy and the cost low. The clinical significance of anti-actin antibodies in patients with chronic liver disease is also discussed.

Counterimmunoelectrophoresis (CIE) for the detection of anti-liver-kidney microsome (LKM) antibodies in the sera of patients with chronic liver disease.

A counterimmunoelectrophoresis (CIE) test for the detection of liver-kidney microsome specific antibodies in human sera is described. By testing different subcellular preparations the LKM antigen was found in the membranes of the smooth endoplasmic reticulum subfraction. The antigen was sensitive to trypsin digestion and behaved as an anionic protein in the experimental conditions used in the test. All sera positive for LKM in immunofluorescence gave a precipitin line of identity while none of the control sera gave a positive reaction. The CIE titers ranged between neat and 1/4096. A significant correlation was observed between the LKM titers obtained in immunofluorescence and those obtained in CIE. Moreover, by absorption experiments, it was concluded that the antigen preparation reactive in CIE was able to abolish the immunofluorescence pattern of LKM positive sera on rat liver and kidney sections. The LKM target antigen, although previously considered a structural protein of microsomal membranes, was shown to solubilize spontaneously during the isolation of microsomal membranes. Counterimmunoelectrophoresis appears to be an appropriate test for anti-LKM antibodies in human sera.

A novel assay for detecting antibodies to cytochrome P4502D6, the molecular target of liver kidney microsomal antibody type 1.

Liver Kidney Microsomal type 1 (LKM1) antibody, the diagnostic marker of autoimmune hepatitis type 2, is also found in a proportion of patients with hepatitis C virus infection (HCV). It is detected conventionally by the subjective immunofluorescence technique. Our aim was to establish a simple and objective enzyme-linked immunosorbent assay (ELISA) that measures antibodies to cytochrome P4502D6 (CYP2D6), the target of LKM1. An indirect ELISA using eukaryotically expressed CYP2D6 was designed. Absorbance values obtained against a reference microsomal preparation were subtracted from those obtained against a microsomal preparation over-expressing CYP2D6, thus removing the non-CYP2D6-specific reaction. Sera from 51 LKM1 positive patients (21 autoimmune hepatitis and 30 with HCV infection), 111 LKM1 negative patients with chronic liver disease (including 20 with HCV infection) and 43 healthy controls were tested. Of 51 patients positive by immunofluorescence, 48 were also positive by ELISA while all the 154 LKM1 negative subjects were also negative by ELISA. There was a high degree of association between IFL and ELISA as demonstrated by a kappa reliability value of 0.96. The absorbance values by ELISA correlated with immunofluorescence LKM1 titres both in autoimmune hepatitis (r = 0.74, p < 0.001) and HCV infection (r = 0.67, p < 0.001). The simple, objective ELISA described has the potential to replace the standard immunofluorescence technique.