Peroxidase-antiperoxidase complex. Binding by Mallory bodies in unfixed tissue

An antigen-antibody complex of horseradish peroxidase, peroxidase-antiperoxidase (PAP), was found to selectively bind to Mallory bodies (MBs). Specific PAP binding to MBs was consistently demonstrated in liver sections from 14 patients with alcoholic cirrhosis and from one patient with hepatoma. Mallory bodies in isolated fractions also bound PAP. No structures stained with PAP in six control sections. The PAP-binding method is useful in the identification of MBs in situ and in isolated fractions. The nature of the affinity of MBs for PAP is not known, but it is postulated that nonspecific protein-immunoglobulin binding is involved.     

RNA extraction from virus-diseased sweet potato for reverse transcriptase polymerase chain reaction analysis

Apoptosis occurs in both clinical and experimental alcoholic liver disease. The mechanisms involved in alcohol-induced apoptosis of liver cells are not completely understood. Induction of cytochrome P450 2E1, the alcohol-inducible cytochrome P450, is one of the proposed mechanisms. Exposure of Hep G2 cells expressing cytochrome P450 2E1 to arachidonic acid leads to increased lipid peroxidation and apoptosis. Increased levels of iron in the liver also promote lipid peroxidation and are associated with increased numbers of apoptotic hepatocytes. Tumor necrosis factor (TNF) acting through its receptors can induce apoptosis in hepatocytes. Increased levels of tumor necrosis factor and its receptors have been described in alcoholic liver disease. The liver is also CD95 receptor positive and in liver tissue from patients with alcoholic hepatitis, the CD95 ligand is expressed at high levels in hepatocytes. Cytotoxic T lymphocytes could, through the CD95 receptor-ligand interaction, promote apoptosis.     

Hepatitis C virus c100 antigen in liver tissue from patients with acute and chronic infection

A pool of murine monoclonal antibodies developed against c100 antigen, a hepatitis C virus-associated protein encoded by the NS3/NS4 virus genome, was used to detect hepatitis C virus in liver biopsy specimens from patients with acute and chronic hepatitis C virus infection. The antigen was present in the cytoplasm of liver cells only. The immunoreactive signal appeared as large, distinct, brilliant fluorescent granules with no clear relationship to cellular structures. No obvious membrane c100 antigen accumulation was observed. Distribution of c100-containing hepatocytes was directly correlated with viral replication in acute hepatitis. All three acute-hepatitis patients were positive for hepatitis C virus RNA (as detected on polymerase chain reaction) in serum and displayed c100 antigen in 50% to 70% of hepatocytes, with a distinct topographical relationship with necrotic areas and inflammatory cell accumulation. Conversely, very low numbers of infected cells and no relationship between tissue c100 antigen expression and sites of liver cell necrosis and inflammation were found in 14 chronic hepatitis C virus infection patients. Furthermore, though all patients had measurable levels of serum hepatitis C virus RNA, only eight (57%) had detectable c100 antigen in liver sections. Indeed, these two distinct immunopathological patterns were inversely related to the development of c100 antibody in serum. Specificity of hepatocellular c100 antigen deposits was established through extensive absorption experiments using structural and nonstructural hepatitis C virus recombinant proteins. However, tissue processing was found to be a crucial step in the demonstration of hepatitis C virus antigen in fresh frozen liver tissue.(ABSTRACT TRUNCATED AT 250 WORDS)     

Nonalcoholic steatohepatitis. Clinicopathological comparison with alcoholic hepatitis in ambulatory and hospitalized patients

This study reports a clinicopathological analysis of 105 patients whose liver histology showed a pattern of alcohol-like steatohepatitis. There were 32 nonalcoholic, 21 asymptomatic ambulatory, and 52 hospitalized alcoholic hepatitis patients. Female sex, obesity, and diabetes predominated in nonalcoholics. Clinical and laboratory presentation were similar in nonalcoholics and ambulatory alcoholics, but different from the hospitalized alcoholics. Histology showed an increasing degree of severity of hepatocellular damage, Mallory bodies, neutrophil and mononuclear infiltration, and pericellular and portal fibrosis from the nonalcoholics to the hospitalized alcoholics, with ambulatory alcoholics displaying an intermediate degree of severity. Steatosis and glycogenated nuclei were prevalent in the obese, diabetic nonalcoholics, of whom 47% had significant fibrosis and 8% cirrhosis, the latter present in 38% and 89% of ambulatory and hospitalized alcoholic hepatitis (P = 0.0001), respectively. In asymptomatic subjects with suspected liver disease, a liver biopsy is the only way of establishing the type and severity of liver lesions.     

Immunoperoxidase staining of hepatitis C virus in formalin-fixed, paraffin-embedded needle liver biopsies

The localization of hepatitis C virus (HCV) in the liver has not been well clarified. We report successful indirect immunoperoxidase staining of the HCV core antigen using polyclonal antibodies raised in rabbits and conventional formalin-fixed, paraffin-embedded needle biopsy sections of liver. The core antigen was distributed in a fine granular pattern diffusely, perisinusoidally, or focally within the hepatocellular cytoplasm of livers from patients with HCV infection. The staining tended to show a more heterogeneous pattern in terms of intensity and distribution in cases of more advanced disease. Hepatocellular carcinoma cells were also frequently stained. HCV immunostaining will provide important information on the pathogenesis and treatment of HCV-related liver diseases.     

Serum levels and in situ expression of TNF-alpha and TNF-alpha binding proteins in inflammatory liver diseases

Cells respond to tumour necrosis factor-alpha (TNF-alpha) via binding to 75-kDa (type A) and 55-kDa (type B) receptors which have different intracellular signalling pathways and can also circulate as soluble molecules. Both receptors are co-expressed in many tissues, but their relative contributions to cellular TNF responses is for most situations unknown. In patients with viral and non-viral inflammatory liver diseases serum TNF-alpha was determined by an immunoenzymetric assay and soluble type A and B TNF receptors (TNF-alpha r) by enzyme-linked immunological and biological assays (ELIBA). In addition, cellular expression of TNF and its binding proteins were studied in liver biopsies by an indirect immunoperoxidase technique. Secretion of TNF-alpha and upregulation of TNF-alpha r-A were particularly prominent in viral hepatitis. Strong TNF-alpha in-situ production by mononuclear cells could be demonstrated in liver biopsies from patients with acute viral hepatitis. However, TNF-alpha r-A was detected only on hepatocytes. Serum TNF-alpha r-A was elevated two-fold in relative abundance over TNF-alpha r-B and was correlated to serum TNF-alpha (r = 0.6464, P < 0.0001). Soluble TNF-alpha r levels normalized, when the viral hepatitis was cleared, and successful therapy of hepatitis B was associated with a temporary rise of TNF-alpha r-A during the initial flare of aminotransferase. Patients with alcoholic hepatitis had also evidence of TNF-alpha activation but clearly differed from patients with viral induced liver diseases: Soluble TNF-alpha r-A and TNF-alpha r-B were highly elevated in equal proportions. In situ analysis in liver biopsies revealed a distinctive pattern of TNF-alpha r expression with strong cytoplasmic staining for both TNF-alpha r-A and B on scattered hepatocytes in addition to infiltrating mononuclear cells. The data propose that TNF release during antiviral immune responses is predominantly associated with TNF-alpha r-A upregulation and shedding, whereas upregulation and shedding of TNF-alpha r-B is more prominent in alcoholic hepatitis. As cytotoxicity and apoptosis by TNF are mediated mainly via TNF-alpha r-B, our results are consistent with more severe TNF-alpha induced liver damage in alcoholic hepatitis as compared to viral hepatitis.     

Selection of human ovarian carcinoma cells with high dissemination potential by repeated passage of the cells in vivo into nude mice, and involvement of Le(x)-determinant in the dissemination potential

Cells of the human tumor cell line RMG-1, derived from a clear-cell adenocarcinoma of the ovary, were injected intraperitoneally into nude mice, and the cells obtained from the tumor nodules in the mesenterium were found to form a larger number of, and larger-sized, tumor nodules than the original RMG-1 cells. The RMG-1-h cells, transferred into culture from the tumor nodules after a 4th in vivo passage, showed a dissemination potential as high as that of cells disseminating directly from the tissues, and exceedingly higher than that of RMG-1 cells. To assess the molecular bases of the different biological properties of RMG-1 and RMG-1-h cells, we compared the content and expression of various carbohydrate antigens in both cells. The chromosomal profile of RMG-1-h cells revealed their human origin and was identical to that of the original RMG-1 cells. In contrast to the broad histogram for the Le(x)-bearing cells among RMG-1 cells in flow cytometry, the weakly and moderately positive cells toward anti-Le(x) antibody were found to be eliminated from the histogram for the RMG-1-h cells, resulting in the enrichment of cells strongly expressing Le(x), which may account for the high dissemination potential. In addition, the adhesion of RMG-1 cells to mesothelial cells was found to be significantly inhibited by pretreatment of the cells with anti-Le(x) antibody, indicating Le(x)-mediated cell-to-cell interaction between ovarian cancer cells and mesothelial cells. By TLC-immunostaining, two Le(x)-glycolipids, III3Fuc alpha-nLc4Cer and V3Fuc alpha-nLc6Cer were detected in both RMG-1 and RMG-1-h cells, and their total concentrations were not significantly different from each other. However, the hydrophobic moieties of Le(x)-glycolipids in RMG-1-h cells were different from those in RMG-1 cells, suggesting that a difference in the structure of the hydrophobic moieties of Le(x) is partly involved in the enhanced reactivity of RMG-1-h cells toward anti-Le(x) antibody. Thus, the high dissemination potential of ovarian cancer cells was shown to be mediated by the Le(x)-determinant and the Le(x)-bearing cells are enriched by repeated in vivo passage of the cells into nude mice.     

Antibodies to soluble liver antigen, P450IID6, and mitochondrial complexes in chronic hepatitis

BACKGROUND: Antibodies to soluble liver antigen, P450IID6, and the E2 subunits of mitochondrial dehydrogenase complexes occur in autoimmune liver diseases, but their specificities and implications are uncertain. The aims of the present study were to assess the importance of these autoantibodies in different types of chronic hepatitis. METHODS: Sera from 62 patients with autoimmune hepatitis, 37 patients with cryptogenic hepatitis, and 19 patients with chronic hepatitis C were assessed under code by enzyme immunoassay. RESULTS: Antibodies to soluble liver antigen were found in 7 patients with autoimmune hepatitis (11%) and 5 patients with cryptogenic disease (14%). Patients with antibodies to soluble liver antigen were indistinguishable from seronegative counterparts with autoimmune hepatitis. Seropositive patients with cryptogenic hepatitis had autoimmune features, and they responded to corticosteroid therapy. Five patients (8%) with autoimmune hepatitis were seropositive for antibodies to mitochondrial complexes. Three lacked antimitochondrial antibodies. None of the patients had antibodies to P450IID6, and patients with chronic hepatitis C were seronegative for all markers. CONCLUSIONS: Antibodies to soluble liver antigen do not define a distinct subgroup of patients with autoimmune hepatitis. They may be found in some patients with corticosteroid-responsive cryptogenic hepatitis. Antibodies to E2 subunits and P450IID6 are uncommon in adults with chronic hepatitis.     

Giant mitochondria in hepatocytes: a diagnostic hint for alcoholic liver disease

One hundred and sixty-five coded liver biopsy specimens were studied by light microscopy to evaluate the occurrence and diagnostic significance of giant mitochondria, which have been identified as periodic acid-Schiff-negative globular hyaline cytoplasmic inclusions of regular outline, clearly distinguishable from Mallory bodies. In 4 cases, electron microscopy confirmed that these globules were in fact enlarged mitochondria. The incidence of giant mitochondria was significantly higher in patients with high alcohol consumption (72%) than in those with low or no alcohol intake (10%). Their presence was related to the amount of daily ethanol consumption and to the shortness of abstinence before the biopsy. It was independent of other changes in the liver, and was detected with similar frequency in biopsies showing different alcoholic liver diseases. Our study emphasizes that giant mitochondria may be detected by light microscopy in a high proportion of alcoholics, and rarely in nonalcoholic liver diseases. Although less specific, they are much more frequent than Mallory bodies. Consequently they should be considered as a diagnostic hint of recent and heavy alcoholsm.     

Distribution and subcellular localization of a growth inhibitory factor in hamster liver and its intracellular partner(s)

The subcellular, intralobular distributions and intracellular partner(s) of a factor which inhibits the proliferation of cell growth (Hashimoto C. et al. (1994) Biochim. Biophys. Acta 1221, 107-117) were determined in hamster livers, using a combination of immunological and biochemical techniques. The IgG fraction from an antiserum raised against the growth inhibitory factor with 37 kDa was shown to be highly specific for the antigen. The nuclear and cytosolic fractions demonstrated inhibitory effects on cell growth and Western blot analysis revealed that both fractions contained the immunoreactive 37 kDa protein with the anti-inhibitory factor IgG but microsomal and mitochondrial fractions did not. The nuclear and cytoplasmic localization of the inhibitory factor were further confirmed by immunochemical staining mediated through the immune IgG and an avidin-biotinylated horseradish peroxidase complex, the parenchymal liver cells were clearly stained, but endothelial and connective tissue cells were not. Although some staining was evident throughout the liver parenchyma, the hepatocytes with most intensively stained nuclei were located in the periportal region. In the liver from hamsters 6 days old or the regenerating hamster livers 3 days after partial hepatectomy, the staining intensity was low and the number of hepatocytes with the inhibitory factor positive nuclei was very few compared with the adult hamster livers. In primary cultures of the isolated hepatocytes from adult hamster the inhibitory factor disappeared from nuclei after incubation for 24-48 h. The extracts of hepatic nuclei from adult hamsters were immunoprecipitated with either the anti-growth inhibitory factor IgG or a monoclonal antibody to the RM protein. The growth inhibitory factor and the RB protein coprecipitated in each case, implying that the proteins were complexed with each other in the nuclei. The RB protein family is composed of two sets of species, an un- or underphosphorylated species and a hyperphosphorylated one. It was suggested that the factor bound preferentially to the un- or underphosphorylated member of the family.     

A histopathological study of alcoholics with chronic HCV infection: comparison with chronic hepatitis C and alcoholic liver disease

To clarify the relationship between hepatitis C virus infection and excessive alcohol intake, we carried out histological examination of the liver in 46 alcoholics with chronic hepatitis C virus infection and compared the findings in 55 patients with chronic hepatitis C, 38 with alcoholic liver disease, and 27 with chronic hepatitis B. The majority of alcoholics with chronic hepatitis C virus infection displayed virus-related histological changes very similar to those in chronic hepatitis C, including frequent lymphoid follicles (34.7%) or aggregates (93.3%) in the portal tracts, mild necroinflammatory change (76.1%) in the parenchyma, and lymphocytosis in sinusoids (83.7%). Liver cell dysplasia and irregular regenerative activity of hepatocytes were rarely observed. The effects of alcohol on the liver were found to be minimal in the majority. These findings could suggest that the hepatic injury in the majority of alcoholics with chronic hepatitis C virus infection in Japan is due to persistent hepatitis C virus infection rather than to alcoholic injury. In addition, our study disclosed that the perivenular fibrosis which is designated as a histological characteristic of alcoholic liver disease is frequently observed in chronic hepatitis C. These similarities suggest that a similar fibrogenesis is present in chronic hepatitis C and alcoholic liver disease.     

Strategy to design peptide inhibitors: structure of a complex of proteinase K with a designed octapeptide inhibitor N-Ac-Pro-Ala-Pro-Phe-DAla-Ala-Ala-Ala-NH2 at 2.5 A resolution

To assess the relationship between hepatitis C virus infection and Fas antigen expression on hepatocytes, we examined changes in hepatic Fas antigen expression in the presence or absence of active hepatitis C virus infection. Twenty patients with chronic hepatitis C infection were treated with interferon and underwent pre- and posttreatment liver biopsies. Patients were classified according to the absence (group A; n = 9) or the presence (group B; n = 11) of hepatitis C virus RNA (HCV-RNA) in the liver after interferon therapy. An immunohistochemical assay showed Fas antigen staining in hepatocytes membranes and cytoplasm with expression concentrated mainly in periportal areas. The percentage of Fas-positive cells in the liver before treatment was not different between group A (39.5+/-19.1%) and group B (32.5+/-15.6%). Hepatic Fas expression was reduced significantly after treatment (24.3+/-10.6%) compared with the pretreatment values in group A (p < 0.05) but not in group B (25.9+/-16.9%). There was no significant difference between the two groups in the degree of histologic improvement. These results suggest that hepatic Fas expression is associated with persistent infection of hepatitis C virus.     

Comparison of the polyethylene glycol antiglobulin test and the use of enzymes in antibody detection and identification

BACKGROUND: The polyethylene glycol indirect antiglobulin test for detection of red cell antibodies was compared with a proven, highly sensitive test system using papain. STUDY DESIGN AND METHODS: Parallel, prospective testing of 1508 samples with polyethylene glycol and with albumin and papain evaluated the sensitivity and specificity of polyethylene glycol. Retrospective analysis of antibody specificities was performed for the 2 years before and the 2 years after the institution of polyethylene glycol testing. RESULTS: Of 1508 prospective screens, 53 (3.5%) had discordant results: 5 were positive only in polyethylene glycol and 48 were positive only in albumin and papain. Upon antibody identification, the 5 samples that were positive only in polyethylene glycol showed 1 anti-D, 2 warm autoantibodies, and 2 false-positive results. The 48 samples that were positive only in albumin and papain showed 1 each of the following: anti-Le(b); anti-P1; anti-S; high-titer, low-avidity antibody; and cold autoantibody; there were 43 false-positive results. False-positive results totaled 12 (0.8%) with polyethylene glycol and 53 (3.5%) with albumin and papain. The retrospective analysis of antibody specificity with polyethylene glycol showed a significant increase in the detection of Fy(a) and/or Fy(b) (p < 0.0002) and Jk(b) (p < 0.0002) antibodies and a decrease in the detection of Le(a) and/or Le(b) antibodies (p < 0.0002). CONCLUSION: Polyethylene glycol retained the high sensitivity of the albumin and papain, while significantly lowering the number of false-positive results and decreasing the detection of antibodies of doubtful clinical significance.     

Alcoholic hepatitis

Alcoholic hepatitis is the precursor of cirrhosis. Susceptibility is independent of amount and duration of ethanol intake or of diet. Centrilobular hyalin, the key morphologic abnormality, sensitizes lymphocytes to secrete factors which may account (in part) for necrosis, liver cell destruction, increased collagen synthesis and development of cirrhosis. Diagnosis may be facilitated by detection of alcoholic hyalin antigen (AHAg) and antibody (AHAb) in serum of patients with alcoholic hepatitis. Treatment requires abstinence. Steroids have not reduced mortality rates. Measures to improve immunologic reactivity may be helpful. Persons unable to abstain should be enrolled in a surveillance group.     

Generation of an antibody to HLA-G in transgenic mice and demonstration of the tissue reactivity of this antibody

A method was devised to generate antibodies against the non-classical class I HLA-G antigen. This consisted of immunising HLA-A2/beta 2m double transgenic mice with HLA-G transfected into mouse Ltk- cells. A polyclonal antibody was obtained which appears to be specific for HLA-G. The staining pattern of this antibody was restricted solely to all populations of extravillous trophoblast. No fetal tissues reacted with this antibody, including those where HLA-G mRNA has been demonstrated, such as fetal eye, thymus and liver. This study confirms that HLA-G is a trophoblast-specific protein, although it remains a possibility that the technique of immunohistology is not sufficiently sensitive to detect low level HLA-G antigen expression in non-trophoblast tissues.     

Evidence for in vivo peroxynitrite production in human chronic hepatitis

During inflammation nitric oxide reacts at near diffusion limited rates with superoxide to form the strong oxidant peroxynitrite. Nitration on the ortho position is a major product of peroxynitrite attack on proteins. In the present study we investigated whether immunohistochemical detection of nitrotyrosine (footprint of peroxynitrite) can be associated with human hepatitis. Paraffin-embedded liver tissue biopsies from patients with chronic active hepatitis, chronic active hepatitis plus cirrhosis and chronic persistent hepatitis exhibit significant specific immunostaining with the antibody to nitrotyrosine. Positive staining was found in 57% and 72% of tissue specimens from patients with chronic hepatitis and cirrhosis, respectively. Immunohistochemical staining of nitrotyrosine residues was found in the hepatocytes and Kuppffer cells of the necrotic area. The presence of nitrotyrosine indicates that oxidants derived from nitric oxide such as peroxynitrite are generated in human hepatitis and may be involved in its pathogenesis.     

A quantitative evaluation of the glycogen content of the hepatocytes from different lobular ares of the normal human liver and in chronic hepatitides of different etiologies

Investigation of glycogen function in hepatocytes of different liver lobule zones is particularly important in understanding glycogen metabolism in humans and animals in norm and pathology. The present study was done to investigate glycogen contents in hepatocytes of different lobule zones of human liver in norm, and in patients with chronic hepatitis of viral or alcohol etiology. Quantitative analysis of glycogen content in hepatocytes of portal and central lobule zones was conducted on slices of human liver (the material of series live punctional biopsies) stained using a quantitative variant of PAS-reaction (Kudryavtseva et al., 1970, 1974). The measurements were done by image analyzer , which allows to make jointly cytophotometric analysis of substance in cells and definition of cell localization in tissue. The results showed clear differences of glycogen contents in different lobule zones in normal liver and in liver during chronic viral and alcohol hepatitis. Glycogen contents in hepatocytes of portal lobule zone were significantly higher than in the central lobule zone in patients with chronic viral hepatitis. Opposite data were obtained in patients with chronic alcohol hepatitis. Significantly higher glycogen contents were found in hepatocytes of the central liver lobule zone. Possible mechanisms of such a phenomenon are discussed . Thus, if glycogen contents in hepatocytes may be taken as an indicator of liver chronic damage degree (as has been shown elsewhere: Kudryavtseva, 1987; Kudryavtseva et al., 1988) the pattern of distribution of hepatocytes with different glycogen content in the liver lobule can be used as an indicator of etiology of chronic hepatitis. The obtained data seem to be important and actual, particularly for diagnostic of subclinical and symptomless forms of these diseases. Further investigation is required to find out reasons and mechanisms of this phenomenon.     

Characterization of three novel monoclonal antibodies against hepatitis C virus core protein

Three novel monoclonal antibodies (MAbs) were established against a recombinant hepatitis C virus (HCV) core protein derived from cloned genotype 1b HCV cDNA. MAbs C7-50 and C8-59 recognize a conserved linear epitope represented by amino acid residues 21 to 40 of the nucleocapsid protein. MAb C8-48 is directed against a strain-specific conformational epitope located within the first 82 amino acids. A sensitive two-site MAb-based immunoradiometric assay was established using antibodies directed against distinct epitopes on the nucleocapsid protein. Processed 21 kDa core protein was detected by immunoblotting in human hepatocellular carcinoma cell lines and primary adult rat hepatocytes transfected with a cytomegalovirus promoter-driven expression construct. Immunofluorescence microscopy studies revealed a granular and vesicular cytoplasmic staining pattern. MAb C7-50 was used successfully to detect HCV core antigen in chronically infected chimpanzee liver tissue. These MAbs represent important reagents for the study of HCV biology and for the development of immunodiagnostic assays.     

Severe hepatitis resulting from toxoplasmosis in a barred owl (Strix varia) from Québec, Canada

A female adult barred owl (Strix varia) had been hurt by a car. Its general status declined gradually within 2 wk with anorexia and inactivity. Necropsy examination revealed marked multifocal pale areas in liver, emaciation, and mild airsacculitis and pericarditis. Histopathologic examination revealed severe acute multifocal hepatic necrosis with numerous protozoal tachyzoites within necrotic foci and in the cytoplasm of hepatocytes and macrophages. These tachyzoites stained with an indirect immunohistochemistry method for Toxoplasma gondii antigens. This is the first reported case of hepatitis resulting from toxoplasmosis in a raptor.     

Serum IgA antibodies to human gut luminal aspirates and human liver in alcoholic liver disease

BACKGROUND: Elevation of serum IgA is a characteristic feature of alcoholic liver disease. It has been proposed that this occurs partly as an antigenic response to gut-derived proteins or acetaldehyde-modified liver proteins, but the principal antigens responsible remain unknown. AIMS: The goal of this study was to determine if serum IgA antibodies were present against human gut luminal antigens or liver antigens in alcoholic liver disease. PATIENTS AND METHODS: Twenty-nine patients with alcoholic liver disease, 10 with primary biliary cirrhosis, 12 with "other" liver diseases, 8 alcoholics, and 20 healthy subjects were studied. Western blotting was used to examine the reactivity of sera from these groups against human small and large bowel aspirates and liver tissue from alcoholic liver disease patients. RESULTS: Serum IgA antibodies to a 140 kDa colonic luminal protein were found in 22 (76%) patients in the alcoholic liver disease group (p < 0.0001), and 7 (24%) patients had serum IgA antibodies to a 40 kDa colonic luminal protein (p = 0.04). These responses were confined to colonic aspirates and not observed in other disease groups, alcoholics or healthy subjects. There was no significant serum IgA response to human liver proteins in alcoholic liver disease. CONCLUSIONS: Serum IgA antibodies to a human 140 kDa colonic luminal protein are frequently found in alcoholic liver disease. This novel antigen may contribute to the increased levels of circulating IgA in alcoholic liver disease.