Expression of cytokine-dependent immune adhesion molecules by hepatocytes and bile duct cells in chronic hepatitis C

A signature for immune response correlates with HCV treatment outcome in Caucasian subjects

Broad proteomic profiling was performed on serum samples of phase 2 studies (PROVE1, PROVE2, and PROVE3) of the direct-acting antiviral drug telaprevir in combination with peg-interferon and ribavirin in subjects with HCV. Using only profiling data from subjects treated with peg-interferon and ribavirin, a signature composed of pretreatment levels of 13 components was identified that correlated well (R(2)=0.68) with subjects' underlying immune response as measured by week 4 viral decline and was highly predictive of sustained virologic response in non-African American subjects (AUC=0.99). The signature was validated by predicting in an independent cohort of non-African American subjects treated with telaprevir, peg-interferon and ribavirin (AUC=0.854). Samples from extreme responders were over-represented in these analyses. Proteins identified as differentially-expressed between responders and non-responders to HCV treatment were quantified using multiple reaction monitoring in samples from all Caucasian subjects in the peg-interferon and ribavirin arms of PROVE1 and PROVE2, revealing 15 proteins that were significantly differentially expressed between treatment responders and non-responders. Seven of the proteins are part of focal adhesions or other macromolecular assemblies that form structural links between integrins and the actin cytoskeleton and are involved in antiviral response.

BIOLOGICAL SIGNIFICANCE

HCV is a significant health problem. We describe a novel approach for identifying markers that predicts HCV treatment response different treatment regimens and use this approach to identify a novel HCV treatment response signature. The signature has potential to guide optimization of HCV treatment regimens.

Elevated sICAM-1 levels in patients with hemorrhagic fever with renal syndrome caused by Hantaan virus

Increased vascular permeability and vascular leakage are characteristic pathological changes in hemorrhagic fever with renal syndrome (HFRS). Vascular endothelial cells are the main targets of Hantaan virus, the etiological agent of the severe form of HFRS. Hantaan virus can induce extensive damage of small blood vessels and capillaries. In vitro infection of human umbilical vein endothelial cells by Hantaan virus can induce the expression of intercellular adhesion molecule-1 (ICAM-1). The involvement of this molecule is implied in human HFRS. In the present study, serum-soluble ICAM-1 (sICAM-1) levels were determined and their relationships with the clinical course and disease severity were investigated in 112 HFRS patients and 30 healthy controls. The results showed that the serum levels of sICAM-1 in HFRS patients at fever, hypotensive, oliguric, and polyuric phases were significantly higher than those in controls (p < 0.001). However, no significant differences between the serum concentrations of sICAM-1 in the milder and more severe groups of patients were observed (p > 0.05). It is suggested that sICAM-1 was involved in the progression of HFRS. Time-dependent determinations of sICAM-1 levels may be indicators for the progression of disease, and elevated levels of sICAM-1 were not suggested to be correlated to disease severity.

Post-transplant reactivation of hepatitis C virus: lymphocyte infiltration and the expression of adhesion molecules and their ligands in liver allografts

Hepatitis C virus (HCV) recurrence after liver transplantation has been associated with chronic rejection. Biopsies from 10 patients with post-transplant HCV were examined for expression of adhesion molecules ICAM-1, VCAM-1, and ELAM-1, number of lymphocytes positive for their ligands LFA-1, VLA-4, and SLeX, and activation markers MHC class II antigens and IL2-R by immunohistochemistry. The phenotypes of the graft-infiltrating lymphocytes were determined. Results were compared to those for patients with normal graft function or rejection. Five recipients with HCV reactivation and one with de novo HCV had a biopsy available showing induction of ICAM-1 in sinusoidal endothelium (p<0.05) and hepatocytes (p<0.01), and Class II antigens in hepatocytes (p<0.01), compared to normal controls. Lymphocytes in the graft infiltrate expressed LFA-1, VLA-4, and Class II antigens, but IL2-R was not significantly expressed. CD3+, CD4+, and CD8+ cells were observed. In our study, HCV recurrence was not associated with acute or chronic rejection, and the inflammation was due to the viral infection.

Influence of hepatitis C virus infection on soluble cellular adhesion molecules in hemodialysis patients

BACKGROUND/AIMS

Higher levels of soluble cellular adhesion molecules have been found to be a strong indicator of endothelial dysfunction and atherosclerosis in the general population. In hemodialysis patients, soluble cellular adhesion molecules have been found at higher levels as well. Such an increase has been considered as a sign of chronic inflammation. Chronic viral hepatitis C (HCV) infection, highly prevalent in hemodialysis patients, is also a disease that can induce chronic inflammation. We conducted a cross-sectional association study of soluble cellular adhesion molecules and hepatitis C in maintenance hemodialysis patients.

METHODS

A total of 87 stable hemodialysis patients were included in this study, mean age was 60.0 +/- 13.7 years. Anti-HCV antibody and HCV RNA assay were done. Patients were divided into anti-HCV-positive and anti-HCV-negative groups. Predialytic serum soluble intercellular adhesion molecules-1 (sICAM-1), soluble vascular cellular adhesion molecules-1 (sVCAM-1), and soluble E-selectin were assayed by commercially available enzyme-linked immunosorbent assay (ELISA) kits. The results were correlated with other hematological and biochemical results.

RESULTS

In the anti-HCV-positive group, the time on hemodialysis was longer (105.5 +/- 65.7 vs. 49.2 +/- 44.0 months, p = 0.001). The sICAM-1, sVCAM-1 and E-selectin levels were higher in the anti-HCV-positive group. HCV infection was determined as an independent determinant of sICAM-1 and sVCAM-1 by multiple linear regression analysis.

CONCLUSION

Elevated serum soluble cellular adhesion molecules are multifactorial in hemodialysis patients. The role of HCV infection must be considered. The clinical significance and implications of soluble cellular adhesion molecules remains to be elucidated.

Helicobacter species sequences in liver samples from patients with and without hepatocellular carcinoma

AIM

Only a minority of patients carrying a defined viral aetiologic agent develop cirrhosis and ultimately hepatocellular carcinoma (HCC), the mechanism underlying the worsening is still undefined. Experimental infection by Helicobacter hepaticus in mice causes chronic hepatitis and HCC and recently, more Helicobacter species (Helicobacter spp.) have been detected in the liver of patients suffering from cholestatic diseases and HCC arising from non-cirrhotic liver. We investigated whether Helicobacter spp. sequences could be detected in the liver of patients with cirrhosis and HCC compared to subjects with metastasis to liver from colon cancer.

METHODS

Twenty-three liver samples from patients operated upon for HCC superimposed on hepatitis C virus (HCV)-related cirrhosis and 6 from patients with resected metastases from colorectal cancer, were tested by polymerase chain reaction for presence of genomic 16S rRNA of Helicobacter genus using specific primers. DNA sequencing and cag A gene analysis were also performed.

RESULTS

Genomic sequences of Helicobacter spp. were found in 17 of 20 (85%) liver samples from patients with HCC and in 2 of 6 samples from patients with liver metastasis. In three samples of the first group the result was uncertain. H pylori was revealed in 16 out of 17 positive samples and Helicobacter pullorum in the other.

CONCLUSION

Helicobacter spp., carcinogenic in mice, were found at a higher frequency in the liver of patients with HCV-related cirrhosis and HCC than those in patients without primary liver disease.

Stromal cell-derived factor-1 from biliary epithelial cells recruits CXCR4-positive cells: implications for inflammatory liver diseases

Although stromal cell-derived factor-1 (SDF-1) plays an important role in hematopoiesis in the fetal liver, the role after birth remains to be clarified. We investigated the role of SDF-1 and its receptor, CXCR4, in 75 patients; this included controls and patients with viral hepatitis, liver cirrhosis, primary biliary cirrhosis, primary sclerosing cholangitis, and autoimmune hepatitis. Interestingly, SDF-1 appeared up-regulated in biliary epithelial cells (BEC) of inflammatory liver disease. Furthermore, in inflammatory liver diseases, SDF-1 was expressed by BEC of interlobular and septal bile ducts and by proliferated bile ductules. The message expression of SDF-1 in BEC was confirmed at a single-cell level by RT-PCR and laser capture microdissection. The plasma levels of SDF-1 were significantly higher in patients with liver diseases than in normal controls. Flow cytometric analysis of the surface expression of CXCR4 showed that most liver-infiltrating lymphocytes express CXCR4 and the intensity was up-regulated more significantly in liver-infiltrating lymphocytes than in peripheral blood lymphocytes. These results suggest that increased SDF-1 production by BEC may play an important role in the recruitment of CXCR4-positive inflammatory cells into the diseased livers. These data are significant because modulation of the SDF-1/CXCR4 interaction has therapeutic implications for inflammatory liver diseases.

Integrin up-regulation in chronic liver disease: relationship with inflammation and fibrosis in chronic hepatitis C

In 94 patients with chronic hepatitis C, the pattern of integrin expression was correlated with firstly, the histological activity index, necro-inflammatory grade, and stage of fibrosis; secondly, the expression of inflammatory markers including ICAM-1; and thirdly, the extent and intensity of laminin deposition in the perisinusoidal matrix. Immunohistochemical results were evaluated according to a semi-quantitative scoring system or by image analysis. Increased beta1 expression was observed in 88.2% of cases. The expression of alpha1 and alpha5 was increased in 55% and 58.5% of cases, respectively. alpha6 chain was detected in 78.7% of cases. There were no statistically significant differences in integrin expression level according to Knodell's score, inflammatory grade, or stage of fibrosis. ICAM-1 expression was higher in patients with high scores for beta1 expression, but the differences were not statistically significant. There were significantly more patients with high scores for beta1 expression among those with continuous perisinusoidal deposition of laminin. Moreover, a close statistical correlation was observed between alpha6 induction and perisinusoidal laminin deposition (p<0.001). The results suggest that integrin up-regulation in chronic hepatitis C is more closely related to the fibrotic process than to the inflammatory lesions. This reinforces the idea that integrin induction in chronic liver disease is part of a coordinated process involved in the progression of liver fibrosis.

Soluble and cell-associated forms of the adhesion molecule LFA-3 (CD58) are differentially regulated by inflammatory cytokines

The adhesion molecule lymphocyte function-associated antigen 3 (LFA-3) (CD58) is an important regulator of immune cell function which occurs as both surface-associated and 'soluble' forms. This study has investigated the inter-relationship and the effects of cytokines on the expression of LFA-3 isoforms. The surface antigen was found to be relatively unaffected by cytokines, but the release of soluble LFA-3 (sLFA-3) was highly responsive to interleukin 1beta (IL-1beta), interferon gamma (IFN-gamma) and tumour necrosis factor alpha (TNF-alpha). This modulation was cell-specific, particularly with regard to IFN-gamma, which up-regulated sLFA-3 release by A431 cells but down-regulated the release of the soluble form from HEp2 and HepG2 cells. We further demonstrated that LFA-3 is also present in a cytoplasmic 'pool' in each of the cells and, moreover, that cleavage of LFA-3 from the cell surface by phospholipase C resulted in an increase in the levels of the intracellular LFA-3 and replacement of the membrane-associated antigen. These observations suggest that the expression of the surface, soluble and intracellular forms of LFA-3 may be linked by regulatory mechanisms which are likely to exert an important influence on inflammatory interactions.

Effects of immunosuppression and organ transplantation on the natural history and immunopathogenesis of hepatitis C virus infection

The hepatitis C virus (HCV) is recognized as the leading cause for parenterally transmitted hepatitis. It is characterized by a high propensity to chronicity. Several efforts have been directed towards understanding the natural history of chronic HCV infection and the immunopathogenic pathways involved in mediating liver injury in the non-immunosuppressed and immunosuppressed states. In the non-immunosuppressed setting, liver damage seems to be largely immune mediated. In contrast, in the non-immunosuppressed state, there are several other factors that may modify the natural course of the infection and play a role in mediating liver injury. In this review we will address the natural history, virological and immunological aspects of HCV infection. Also, the role played by immunosuppression and organ transplantation in modifying the course of the infection and the pathogenesis of liver injury will be discussed.

Serum cytokine values and fatigue in chronic hepatitis C infection

Patients with chronic hepatitis C infection often experience fatigue. In many clinical situations, an association between fatigue and altered serum cytokine levels has been found. Altered cytokine levels in patients with hepatitis C have not shown a correlation with the degree of serum transaminase elevation or pathological change on liver biopsy. The aim of our study was to examine whether there was an association between abnormal serum cytokine levels and fatigue in patients with compensated chronic hepatitis C. Patients referred to a tertiary care hepatology clinic who were hepatitis C antibody positive and who had elevated alanine aminotransferase (ALT) levels were eligible for entry into the study. A control group was also included. Subjects in both groups who had characteristics other than hepatitis C that were known to alter cytokine values and/or cause fatigue were excluded. Patients completed a validated questionnaire to determine their fatigue severity score (FSS). Bioassays were used to measure interleukin (IL)-1, IL-6 and tumour necrosis factor-alpha (TNF-alpha) levels in early morning serum samples taken from patients and controls. Altered cytokine values were defined as those more than two standard deviations above the mean control value. Data was analysed using SPSS, version 8.01. Of the 78 patients with chronic hepatitis C who participated in the study, 19 (24%), 24 (30%) and 45 (56%) had elevated levels of IL-1, IL-6 and TNF-alpha, respectively, compared with only two (6%) of the control group who had elevation of any of the three cytokines. No correlation was found between the FSS and serum cytokine levels, when analysed singly or in combination, in patients with chronic hepatitis C. Hence, alteration in early morning serum levels of IL-1, IL-6 and TNF-alpha in patients with chronic hepatitis C infection and elevated ALT levels bear no correlation with the symptom of fatigue.

Helicobacter infection and cirrhosis in hepatitis C virus carriage: is it an innocent bystander or a troublemaker?

Since it has been shown that Helicobacter hepaticus causes both chronic hepatitis and hepatocellular carcinoma (HCC) in mice, it is suggested that differences in the progression of chronic hepatitis C may be due to a cofactor stemming from co-infection by bacteria, especially Helicobacter pylori, and/or other Helicobacter species. An assessment was made of the prevalence of H. pylori infection in HCV-positive cirrhotic patients. The presence of Helicobacter species (spp). was evaluated in resected liver tissue from HCC patients. Serum anti-H. pylori IgG antibodies were determined in 70 males with a clinical and/or histological diagnosis of cirrhosis and HCV infection and in 310 age-matched male blood donors. The prevalences of H. pylori antibody were 77% (54/70) and 59% (183/310) (P 0.004). Primers identifying 26 Helicobacter species were used to determine the presence of the genomic 16S rRNA of this genus in liver tissue resected from 25 cirrhotic HCC patients. Genomic sequences corresponding to H. pylori and H. pullorum were identified in 23 of these 25 livers. Together, these findings support the proposal that H. pylori is implicated in the pathogenesis and progression of cirrhosis, particularly in HCV-infected individuals. Involvement of Helicobacter spp. in HCC also seems highly possible.

Immunological and virological predictors of outcome during interferon-alpha therapy of chronic hepatitis C

Results from a multicentre, clinical trial of interferon-alpha2a (IFN-alpha2a) for the treatment of chronic hepatitis C are reported. Serum hepatitis C virus (HCV) RNA levels were monitored as follows: before, and 2 days after, the first administration of IFN-alpha2a; during and at the end of treatment; and 6 months after completion of therapy. Peripheral blood lymphocyte subpopulations were measured, by two-colour flow cytometry, before and 3 h after the first intramuscular (i.m.) administration of 9 mega units (MU) of IFN-alpha2a. Virological responders had a significantly lower pretreatment level of CD11+ CD8- lymphocytes. Biochemical responders had significantly lower pretreatment levels of CD11- CD8+, human leucocyte antigen (HLA) DR- CD4- and HLA DR- CD8+ populations, and a higher pretreatment HLA DR+ CD4- population. These pretreatment differences disappeared 3 h after the first i.m. administration of IFN-alpha2a. CD11- CD8+ and HLA DR+ CD8+ cell populations became significantly lower in virological responders 3 h after the first i. m. administration of IFN-alpha2a. HLA DR+ CD4+ cell populations were increased less in biochemical responders. Thus, T-lymphocyte subpopulations were different between responders and non-responders to IFN therapy and IFN-modulated host immunity. Multivariate analysis showed that the pretreatment CD11+ CD8- cell population was an independent predictive factor of response to therapy. On the other hand, patients whose serum HCV RNA cleared or decreased within the first 2 days of IFN-alpha2a therapy were more likely to achieve a virological response. This predictive factor, however, was not an independent factor by multivariate analysis. These results suggest that host immunity is an important factor in response to IFN therapy, and HCV clearance within the first 2 days is a good predictive factor of response.

Soluble HLA class I antigens in chronic hepatitis C: a disease-associated manifestation or molecules modulating immunoresponsiveness?

The occurrence of high levels of soluble human leukocyte class I antigens (sHLA-I) represents an usual finding during the course of different clinical conditions, such as viral infections and autoimmune disorders. On the other hand, the well known property of sHLA-I to modulate T cell responsiveness could be taken as an advantage to improve long-term allograft acceptance. Recent data have pointed out that subjects with chronic hepatitis C virus (HCV) infection exhibit high amounts of sHLA-I, a pattern which has also been used for monitoring host responsiveness to interferon alpha (IFN-alpha) therapy. However, the lack of correlation between lymphocyte infiltration at liver site and disease biological activity suggests a potential role for sHLA-I in T cell dysfunction during chronic hepatitis C. sHLA-I antigens may, in fact, either interact with T cell receptor delivering an inhibitory signal or trigger cytotoxic T lymphocyte apoptosis by inducing CD95 ligand expression. Both events seem to favour HCV replication and liver tissue damage progression. Alltogether, these findings indicate that, besides viral variant generation and HCV core-mediated immunosuppression, sHLA-I may contribute to the imbalance of immunoresponsiveness during chronic HCV infection.

LFA-3 (CD58) mediates T-lymphocyte adhesion in chronic inflammatory infiltrates

Previous studies have suggested that LFA-3 has an important role in a number of chronic inflammatory pathologies, although an active role for LFA-3 within in vivo inflammatory reactions has not previously been directly observed in humans. To assess the importance of LFA-3 in this process, this study used an adaptation of the Stamper-Woodruff lymphocyte adhesion assay to measure the binding of exogenous activated lymphocytes to the T-cell-dominated chronic inflammatory infiltrate of oral lichen planus. Antibody blockade experiments showed that anti-LFA-3 monoclonal antibody reduced lymphocyte adhesion by approximately 29%, while anti-ICAM-1 produced a reduction of 26%. These results thus suggest that both LFA-3 and ICAM-1 are likely to mediate cell-cell interactions within lesional tissues in vivo. Moreover, these findings are also the first to directly demonstrate that LFA-3-mediated adhesion, like that of ICAM-1, is functionally important in the molecular pathology of inflammatory mucosal disease.

Hepatitis C virus infection and bone marrow transplantation: a cohort study with 10-year follow-up

Before the introduction of routine blood donor screening in 1991, marrow transplant recipients were at significant transfusion-associated risk for infection with hepatitis C virus (HCV). We followed a cohort of 355 patients undergoing transplant in Seattle during 1987 to 1988 to determine (1) the impact of pretransplant HCV infection on the occurrence and severity of venocclusive disease (VOD); (2) the impact of HCV infection on liver dysfunction, other than VOD, occurring between 21 and 60 days after transplantation; and (3) the natural history of post-transplant HCV liver disease with a 10-year follow-up. HCV-RNA status was determined on serum stored before transplant and at day 100 post-transplant. Sixty-two (17%) patients were HCV-RNA positive before transplant, and 113 (32%) were HCV-RNA positive by day 100 post-transplant (or before death). Severe VOD developed in 22 of 46 (48%) evaluable patients with pretransplant HCV infection and in 150 of 229 (14%) evaluable patients without HCV (P <.0001). In multivariable analysis of risk factors for developing VOD, pretransplant HCV infection associated with elevated serum aspartate transaminase (AST) levels predicted the development of severe VOD (relative risk, 9.6; P =.0001). The presence of HCV with normal AST levels before transplant was not a risk factor for severe VOD. Between 21 and 60 days after transplant, HCV-RNA positive-patients had higher AST levels (median 101 U/L), but similar alkaline phosphatase and total bilirubin levels compared with HCV-negative patients, suggesting that cholestatic liver disease (particularly graft-versus-host disease [GVHD]) was not related to HCV infection. An acute flare of hepatitis (AST >10 times the upper limit of normal) developed at a mean of 136 +/- 58 days in 31% of HCV-positive patients; no patients developed fulminant hepatitis. Between 5 and 10 years after transplant, 57% of HCV-positive and 6% of HCV-negative patients had mild to moderate elevations of AST (P <. 0001), but HCV infection was not associated with excess mortality between 3 and 10 years after bone marrow transplantation. In summary, HCV infection with elevated AST levels is a significant risk factor for severe VOD after marrow transplant. However, the decision to proceed to transplantation in HCV-positive patients must balance the absolute risk of death from VOD against the risks of the underlying disease. In long-term survivors, HCV infection is not associated with excess mortality over 10 years of follow-up.

Viral genotypes as determinants of autoimmune expression in chronic hepatitis C

OBJECTIVE

To correlate viral genotypes with the immune manifestations of chronic hepatitis C and evaluate the effect of immune features on disease expression and response to antiviral treatment.

DESIGN

We undertook a retrospective analysis of 67 patients with chronic hepatitis C.

MATERIAL AND METHODS

Patients were selected for study if they had been screened for autoantibodies and concurrent immune diseases and if viral genotyping had been performed or was possible. Concurrent immune manifestations and responses to interferon therapy were determined.

RESULTS

Of the 67 patients, 18 (27%) had one or more immune features. Immune manifestations occurred as commonly in patients with genotype 1 as in those with other genotypes (30% versus 14%; P = 0.3). Concurrent immune features did not distinguish patients, and responses to interferon therapy were similar between patients with and those without immune manifestations. None of the 14 patients with concurrent immune diseases or high-titer autoantibodies (serum titers, 1:320 or more) entered remission during interferon treatment. In contrast, 6 of 53 patients without concurrent immune diseases and no or low-titer autoantibodies had treatment-related remission. These differences, however, were not statistically significant (0% versus 11%; P = 0.3).

CONCLUSION

Autoantibodies and concurrent immune diseases are not associated with a particular viral genotype, clinical profile, or treatment outcome. Larger studies are necessary for complete assessment of the influence of prominent immune manifestations on treatment response.

Inhibition of macrophages with gadolinium chloride alters intercellular adhesion molecule-1 expression in the liver during acute endotoxemia in rats

Cell adhesion molecules are important for localized accumulation of phagocytes at sites of tissue damage. In the present studies, we analyzed the effects of blocking hepatic macrophages on expression of beta2 integrins and intercellular adhesion molecule-1 (ICAM-1) adhesion molecules on liver cells during acute endotoxemia. Flow cytometric analysis revealed distinct subpopulations of macrophages from control animals that varied on the basis of their size and density. In contrast, hepatocytes and endothelial cells were relatively homogeneous. Treatment of rats with endotoxin (5 mg/kg, intravenously) resulted in a time-dependent increase in the percentage of small, dense macrophages and a progressive loss of larger, less-dense cells. In contrast, no major effects were observed on the physical properties of hepatocytes or endothelial cells. ICAM-1 was found to be constitutively expressed on endothelial cells and hepatocytes, as well as on macrophages. Induction of acute endotoxemia resulted in a time-dependent increase in ICAM-1 expression on hepatocytes, which was observed within 3 hours and reached a maximum after 24 hours. An increase in ICAM-1 expression was also observed on endothelial cells and on macrophages at 3 hours, followed by a decrease at 24 to 48 hours. Macrophages and endothelial cells also constitutively expressed beta2 integrins. Induction of acute endotoxemia had no effect on beta2 integrin expression by these cells. Pretreatment of rats with gadolinium chloride (GdCl3), a macrophage inhibitor known to block endotoxin-induced liver injury, abrogated the effects of endotoxin on ICAM-1 expression by hepatocytes and macrophages. In contrast, ICAM-1 expression on endothelial cells increased. Interestingly, treatment of rats with GdCl3 alone resulted in a marked increase in expression of ICAM-1 on endothelial cells and hepatocytes, and of beta2 integrins on macrophages and endothelial cells. Taken together, these data suggest that ICAM-1 is involved in mediating macrophage adherence and accumulation in the liver during endotoxemia. Furthermore, macrophages appear to regulate expression of this cell adhesion molecule on parenchymal cells.

Expression and regulation of cell adhesion molecules by hepatic stellate cells (HSC) of rat liver: involvement of HSC in recruitment of inflammatory cells during hepatic tissue repair

Hepatic stellate cells (HSC), a pericyte-like nonparenchymal liver cell population, are regarded as the principal matrix-synthesizing cells of fibrotic liver. They might also play a role during liver inflammation. The present study analyzed (i) expression of cell adhesion molecules (CAMs) mediating cell infiltration, like intercellular adhesion molecule-1 (I-CAM-1) and vascular cell adhesion molecule-1 (V-CAM-1), by HSC, (ii) CAM regulation in HSC by growth factors and inflammatory cytokines, and (iii) CAM expression in situ during liver inflammation, using immunochemistry and Northern blot analysis. I-CAM-1 and V-CAM-1 expression was present in HSC in vitro and in cells located in the sinusoidal/perisinusoidal area of normal liver. Growth factors, eg, transforming growth factor-beta1, down-regulated I-CAM-1- and V-CAM-1-coding mRNAs and stimulated N-CAM expression of HSC. In contrast, inflammatory cytokines like tumor necrosis factor-alpha reduced N-CAM-coding mRNAs, whereas induction of I-CAM-1- and V-CAM-1-specific transcripts increased several fold. In situ, messengers specific for I-CAM-1 and V-CAM-1 were induced 3 hours after CCl4 treatment (thereby preceding mononuclear cell infiltration starting at 12 hours), were expressed at maximal levels 9-12 hours after CCl4 application, and decreased afterwards. I-CAM-1 and V-CAM-1 immunoreactivity increased in a linear fashion starting 3 hours after CCl4-induced liver injury, was detected in highest amounts at 24-48 hours characterized by maximal cell infiltration, and returned to baseline values at 96 hours. Interestingly, the induction/repression of CAM-specific messengers paralleled the time kinetics of tumor necrosis factor-alpha transforming growth factor-beta1 expression in injured liver. HSC might be important during the onset of hepatic tissue injury as proinflammatory elements and might interact with I-CAM-1 and V-CAM-1 ligand-bearing cells, namely lymphocyte function-associated antigen-1- or Mac-1/very late activation antigen-4-positive inflammatory cells, thereby modulating the recruitment and migration of mononuclear cells within the perisinusoidal space of diseased livers.

Expression and regulation of intercellular adhesion molecule-1 (ICAM-1) in organotypic cultures of rat liver tissue

BACKGROUND/AIMS

The objective of the present study was to analyze the expression and regulation of intercellular adhesion molecule-1 (ICAM-1) in organotypic cultures of rat liver slices, which preserve the normal microenvironment of liver cells.

METHODS

Rat liver slices were maintained in culture for 15 min to 24 h and examined for ICAM-1 expression by immunohistochemistry and Western blotting in basal conditions and after stimulation with 1000 IU/ml interferon-gamma (IFNgamma), 1000 IU/ml tumor necrosis factor-alpha (TNF alpha) and 50 microg/ml endotoxin. Immunohistochemical results were evaluated using a semiquantitative scoring system.

RESULTS

In uncultured slices, ICAM-1 was not detected on hepatocytes. In unstimulated liver slices maintained in organotypic culture, ICAM-1 was induced at the surface of scattered hepatocytes (score at 15 min, 0.33+/-0.47 and at 24 h, 1.17+/-0.69). After 4 h of stimulation, a significant increase in ICAM-1 expression by hepatocytes and adjacent sinusoidal cells, but not by intra-hepatic biliary epithelial cells, was observed for IFNgamma (score: 2.35+/-0.47) and endotoxin (score: 2.67+/-0.47), but not with TNF alpha (score: 0.66+/-0.47). After 24 h of stimulation, a further increase in the extent of ICAM-1 expression by hepatocytes was observed for IFNgamma (score: 3.67+/-0.47) and endotoxin (score: 4.0+/-0.0), and a significant overexpression of ICAM-1 by hepatocytes was detectable after treatment with TNF alpha (score: 3.67+/-0.47).

CONCLUSIONS

In rat liver organotypic cultures, TNF alpha, IFNgamma and endotoxin induce the expression of ICAM-1 in hepatocytes and adjacent sinusoidal endothelial cells, but not in portal tracts.

Soluble adhesion molecules correlate with liver inflammation and fibrosis in chronic hepatitis C treated with interferon-alpha

BACKGROUND

In chronic hepatitis C the relation of circulating adhesion molecules to disease features before, during and after therapy has not been completely established.

AIM

To analyse the basal levels of circulating adhesins and the changes induced by interferon in these patients.

METHODS

We studied, using ELISA assays, the serum levels of soluble intercellular adhesion molecule-1 (sICAM-1) and vascular cell adhesion molecule-1 (sVCAM-1) in 52 patients with chronic hepatitis C on entry, prior to finalizing a 6-month course of interferon-alpha therapy and at the end of the follow-up. Correlations with clinical, virological and histological features, including inflammation and fibrosis, were calculated by Pearson's r-test.

RESULTS

Liver necroinflammation was more closely related to sICAM-1 (r = 0.54, P = 0.0000) than to sVCAM-1 (r = 0.32, P = 0.02). Fibrosis, both as serum pIIIP and histological scoring, was, however, clearly related to sVCAM-1 (1071+/-291 in patients who scored 0-2 vs. 1870+/-458 in patients who scored 3-4; P = 0.0000). Severe fibrosis was never found below a sVCAM-1 cut-off threshold of 1300 ng/mL. Levels of both adhesins did not correlate with viraemia and were comparable among 1b and non-1b genotypes. Sustained response to interferon was significantly related to low viraemia (P = 0.03), non-lb type (P = 0.04) and low sICAM-1 (P = 0.04), but not to sVCAM-1. On finalizing therapy, patients with normal transaminases had reduced sICAM-1 (P = 0.0005), but not sVCAM-1 levels.

CONCLUSIONS

In chronic hepatitis C, sICAM-1 was a marker of liver necroinflammation while sVCAM-1 reflected fibrosis. Both low sVCAM-1 and pIIIP serum concentrations were strictly linked, suggesting that measuring sVCAM-1 could give information on the degree of liver fibroplasia.

Costimulatory molecules and cytotoxic T cells in chronic hepatitis C: defence mechanisms devoted to host integrity or harmful events favouring liver injury progression? A review

The recruitment of antigen-specific lymphocytes at liver site represents a prominent feature in patients chronically infected with hepatitis C virus (HCV). However, despite the strong and multispecific response, chronic infection leads in a significant number of cases to the development of cirrhosis and hepatocellular carcinoma. The finding that the expression of CD80 structure positively correlates with disease histological worsening points out a role for the costimulatory pathway in the progression of liver cell injury. On the other hand, the demonstration of CD95 and CD95-ligand positive cells in the context of periportal areas, a pattern which is not strictly associated to HCV tissue distribution, indicates the occurrence of either virus-infected or innocent bystander hepatocyte killing. Nonetheless, the persistence of HCV, in spite of cytotoxic T lymphocyte (CTL) liver recruitment, suggests a possible in-situ imbalance of cytotoxic activities, above all referred to perforin-granzyme-dependent necrosis. Altogether, these findings outline that several factors might be involved in HCV-driven immunopathogenesis. Therefore, the fully clarification of these mechanisms may offer a suitable therapeutical approach for the improvement of clinical outcome in chronic hepatitis C.

Immunoresponsiveness in chronic hepatitis C patients: correlation between tissue and serum findings

In the present study, intrahepatic CD8+ lymphocyte infiltrates as well as HLA class I and CD54 (ICAM-1) antigen expression at both tissue and serum levels were evaluated in 54 untreated patients with chronic hepatitis C stratified on the basis of histological diagnosis (Chronic Persistent Hepatitis/Chronic Lobular Hepatitis -CPH/CLH- and Chronic Active Hepatitis -CAH-: 22 and 32 subjects, respectively). The relationships between soluble HLA-I (sHLA-I) and ICAM-1 (sICAM-1) serum levels and their membrane-bound counterparts, CD8+ liver infiltration and serum alanine aminotransferase (ALT) were also studied. A strong HLA-I and CD54 tissue expression, associated to the presence of CD8+ cell infiltrates in necro-inflammatory areas, and elevated sHLA-I and sICAM-1 serum amounts were observed in all patients. At the same time, no difference was found at tissue level between the two groups of patients with respect to the mean scores of HLA-I and CD54 expression, while CAH subjects displayed a significantly higher CD8 periportal and lobular reactivity in comparison to the other subset. Serological assays outlined higher values of circulating HLA-I molecules in CPH/CLH patients and higher sICAM-1 levels in the CAH group. Finally, a negative correlation was found between sHLA-I and ALT in CAH subjects while, in all patients, sICAM-1 positively correlated with both CD8 tissue infiltration and ALT. Our findings confirm the occurrence of an immune activation status during chronic hepatitis C and suggest that sHLA-I molecules might play a down-modulating role on immunoresponsiveness of these patients.

Effect of tumor necrosis factor alpha and intercellular adhesion molecule-1 expression on immunogenicity of murine liver cells in mice

Adhesion molecules such as intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) have been implicated in the pathogenesis of various inflammatory liver disease states, including viral and autoimmune hepatitis as well as liver allograft rejection. Tumor necrosis factor alpha (TNF-alpha) is an inflammatory cytokine known to up-regulate adhesion molecules as well as major histocompatibility complex (MHC) class I expression, and has been demonstrated to be important in the rejection of vascularized organ allografts. The current studies address the effect of TNF-alpha and the role of ICAM-1 expression on liver cell immunogenicity in vitro in mixed lymphocyte hepatocyte culture (MLHC), in vitro in mixed lymphocyte liver nonparenchymal cell culture (MLNPC), in vivo in hepatocyte sponge matrix allografts (HC-SMA), and in vivo in liver nonparenchymal cell sponge matrix allografts (NPC-SMA). Purified allogeneic hepatocytes (HC) and liver nonparenchymal cells (NPC) under naive, unstimulated conditions demonstrated different profiles of MHC antigen and adhesion molecule expression, but both liver cell populations stimulated the proliferation and development of allospecific cytotoxic effectors in vitro and in vivo. Despite significant up-regulation of MHC class I and ICAM-1 on both HC and liver NPCs by in vivo treatment with TNF-alpha, the immunogenicity of TNF-alpha-stimulated liver cells was not appreciably different from naive, unstimulated liver cells. In contrast, ICAM-1-negative HC and NPCs were significantly less immunogenic both in terms of lymphocyte proliferative responses and the generation of allospecific cytolytic effectors. These results suggest that constitutive expression of ICAM-1 enhances the immunogenicity of "donor" liver cells but is not absolutely required to elicit immune responses to allogeneic liver cells. Further studies to determine the role of adhesion molecule expression on trafficking of host immune cells to the liver and the role of adhesion molecule expression by host cells are required to clarify their role in immune responses to liver cells.

Host- and disease-specific factors affecting steatosis in chronic hepatitis C

BACKGROUND/AIM

Steatosis is commonly present in chronic hepatitis C. Our aim was to evaluate host- and disease-specific factors associated with its occurrence.

METHODS

Histologic findings in 60 patients were correlated with body mass index, human leukocyte antigens, and other conventional parameters. Comparisons were made with 41 patients who had nonalcoholic steatohepatitis and 18 patients who had chronic hepatitis B.

RESULTS

Patients with chronic hepatitis C and steatosis had lower serum concentrations of gamma-globulin (p=0.01) and immunoglobulin G (p=0.05) than their counterparts without steatosis, and they had a lower frequency of antinuclear antibodies (19% versus 52%, p=0.01). They also had a higher mean body mass index (p=0.002) and a greater frequency of risk factors for steatosis (70% versus 34%, p=0.009). These risk factors, however, occurred more commonly in patients with nonalcoholic steatosis (p=0.007). Furthermore, fat deposition occurred more often in chronic hepatitis C than in chronic hepatitis B (52% versus 22%, p=0.03), despite comparable metabolic findings. The degree of steatosis in chronic hepatitis C was not associated with individual metabolic features.

CONCLUSIONS

Steatosis in chronic hepatitis C is mainly a viral effect, and host-dependent metabolic factors may potentiate the manifestation. Fat deposition is associated with less immunoreactivity and it may connote a distinctive pathogenic mechanism.

Plasma hydroxy metronidazole/metronidazole ratio in anti-HCV carriers with and without apparent liver disease

AIMS

To evaluate plasma hydroxy-metronidazole/metronidazole ratio as a dynamic liver function test in HCV-infected individuals with/without liver disease, in the absence of liver cirrhosis.

METHODS

Metronidazole was administered intravenously in healthy volunteers, asymptomatic anti-HCV-positive blood donors, and in chronic hepatitis C patients. Serology to HCV was determined by a second generation assay and confirmed by gelatin particle agglutination test using recombinant antigens C22-3 and C200. Plasma concentration of metronidazole and hydroxy-metronidazole was measured by high performance liquid chromatography in samples collected 5, 10, 20 and 30 min following the end of metronidazole infusion.

RESULTS

Chronic hepatitis C patients had abnormal liver enzymes, while healthy volunteers and anti-HCV-positive blood donors had normal liver biochemistry tests. Plasma metronidazole concentration was similar in all groups studied. Plasma hydroxy-metronidazole/metronidazole ratio was significantly reduced in HCV-infected subjects, an effect observed 10 min after the end of drug infusion.

CONCLUSIONS

Metronidazole clearance is impaired in anti-HCV-positive blood donors and chronic hepatitis C patients, indicating that HCV is capable of affecting liver function at early stages of the disease. The metronidazole clearance test can detect impaired liver function in HCV-infected individuals even in the absence of liver cirrhosis.

Paraneoplastic demyelinating neuropathy, subacute sensory neuropathy, and anti-Hu antibodies: clinicopathological study of an autopsy case

A patient with anti-Hu antibodies, small-cell lung carcinoma, and autopsy-proven subacute sensory neuropathy had early slowing of motor and sensory conduction velocities. In the peripheral nerves, chronic demyelinating and remyelinating lesions with axonal degeneration were associated with an inflammatory reaction consisting of CD8+ T cells and CD68+ macrophages. On immunohistochemical testing, the patient's serum did not react with normal nerve, suggesting that the Hu proteins were not the target of the inflammatory reaction in the nerve.

Expression of the membrane attack complex of complement and its inhibitors during human liver allograft transplantation

BACKGROUND/AIMS

In order to test the possible role of activated complement in human liver allograft rejection, we evaluated the expression of the membrane attack complex of complement, its soluble inhibitors clusterin and vitronectin and its membrane inhibitor protectin during the evolution of liver transplants.

METHODS

An indirect immunoperoxidase technique was applied to biopsy specimens obtained from liver allografts in 16 patients without complications, nine with acute rejection, four with chronic rejection and five with biliary complications.

RESULTS

Two types of membrane attack complex deposition were observed: (a) extracellular deposits in portal tracts and perisinusoidal matrix, associated with clusterin and vitronectin, similar to those found in the normal liver; and (b) intra-portal vascular deposits, devoid of clusterin and vitronectin. Vascular membrane attack complex deposition was detected in four clinically stable patients, three patients with chronic rejection and two patients with biliary complications. In clinically stable patients, vascular membrane attack complex deposition was restricted to large portal vessels and was detected in a minority of portal tracts. In patients with chronic rejection or biliary complications, vascular membrane attack complex deposition was detected along both large and small portal vessels and was present in the majority of portal tracts. Protectin induction on hepatocytes was detected in 33 cases.

CONCLUSIONS

Our results suggest that membrane attack complex deposition is unlikely to play a major role in the pathogenesis of acute liver allograft rejection but may contribute to the vascular and biliary lesions observed in chronic rejection.

Cytomegalovirus viremia: risk factor for allograft cirrhosis after liver transplantation for hepatitis C

BACKGROUND

Despite recent advances in diagnosis and treatment, cytomegalovirus (CMV) infection continues to be a common cause of morbidity in liver transplant (LT) recipients. Because CMV infection suppresses cell-mediated immunity, which seems to be important in neutralizing hepatitis C virus (HCV) infection, we assessed the impact of CMV infection on histopathological HCV recurrence after LT.

METHODS

The study group was comprised of 43 consecutive LT recipients with at least 6 months of histologic follow-up. Group 1 consisted of the 8 patients who developed CMV viremia after LT; group 2 comprised the 35 patients without CMV viremia. There was no significant difference with regard to age, initial immunosuppression, incidence of rejection, distribution of HCV genotypes, or mean follow-up between the groups. Semiquantitative histopathologic assessment of allograft hepatitis was performed using the Knodell's score.

RESULTS

The mean total Knodell score of the final allograft biopsy was significantly greater in group 1 patients (P=0.016), with most of the difference due to periportal/bridging necrosis (P=0.009) and lobular activity subitem (P=0.01) scores. Half of the CMV viremic patients eventually developed allograft cirrhosis as compared with 11% of the CMV-negative patients (P=0.027). Accordingly, the cirrhosis-free actuarial survival by Kaplan-Meier estimates was significantly diminished in the CMV viremic patients. Glycoprotein B genotype analysis of CMV isolates revealed no significant differences between patients who did and those who did not develop allograft cirrhosis.

CONCLUSIONS

After LT for chronic HCV, patients who develop CMV viremia incur a significantly greater risk of severe HCV recurrence.

Pruritus in chronic hepatitis C: association with high serum bile acids, advanced pathology, and bile duct abnormalities

Pruritus is a common symptom of chronic cholestatic liver diseases but is considered rare in chronic hepatitis. We observed pruritus to be an unusually common complaint in patients with advanced chronic hepatitis C. We reviewed the records of 175 chronic hepatitis C patients to identify patients with severe, diffuse, unexplained pruritus; 12 consecutive prospective patients undergoing liver biopsy for chronic hepatitis C served as controls. Assessment included laboratory biochemical tests and assessment of liver pathology by stage, grade, hepatic activity index, and a bile duct score. Pruritus was present in nine (5.1%) patients. Serum AST, ALT, alkaline phosphatase, GGTP, total bilirubin, and ferritin were similar in pruritics and controls. Pruritics had higher serum bile acids (2028.4 +/- 223.1 mmol/liter vs 423.1 +/- 194.3, P < 0.001), higher transferrin saturation (57.5 +/- 6.8% vs 33.2 +/- 3.3, P < 0.01), and lower HCV RNA by bDNA (24.5 +/- 12.7 x 10(5) vs 172.7 +/- 54.1 x 10(5), P < 0.05). Pathology revealed cirrhosis in 6/9 (66.6%) pruritics vs 1/12 (8.3%) controls (P < 0.01). Pruritics had higher pathologic stage (3.7 +/- 0.2 vs 2.2 +/- 0.4, P < 0.01), grade (4.4 +/- 0.2 vs 2.1 +/- 0.2, P < 0.001), activity index (14.3 +/- 1.9 vs 8.6 +/- 1.9, P < 0.025), and bile duct score (7.6 +/- 0.6 vs 4.7 +/- 0.4, P < 0.01). Of eight pruritics treated with IFN-alpha2b, two had complete ALT response and one relapsed. Pruritus followed a relapsing course and only three patients partially responded despite a variety of interventions. In conclusion, pruritus is a common complication of advanced CHC. Its presence is associated with high serum bile acids, advanced pathology and bile duct abnormalities. The clinical course of pruritus is relapsing and response to therapy is inconsistent. These features suggest that pruritus in CHC has a pathogenesis that may vary from that of chronic cholestatic diseases.

Detection of a soluble form of the human adhesion receptor lymphocyte function-associated antigen-3 (LFA-3) in patients with chronic liver disease

BACKGROUND/AIMS

Multiple immune functions, such as cytotoxic reactions, B cell differentiation, and monocyte activation, are mediated via the adhesion receptor/ligand pairs CD2/lymphocyte function-associated antigen(LFA)-3 and LFA-1/ intercellular adhesion molecule(ICAM)-1. Since soluble forms of LFA-3 (sLFA-3) and ICAM-1 (sICAM-1) can interfere with these functions, we asked whether increased levels of sLFA-3 can be found in patients with different forms of chronic liver disease and/or hepatocellular carcinoma.

METHODS

sLFA-3 was measured in sera from 84 patients with chronic liver disease (39 with chronic viral liver disease, 30 with autoimmune liver disease, 12 with alcoholic cirrhosis, 3 with other causes of cirrhosis), 24 patients with hepatocellular carcinoma (15 with and 9 without cirrhosis), and 61 normal controls. From 36 of the patients with liver cirrhosis, arterial and hepatic venous serum samples were simultaneously obtained and tested for sLFA-3 and sICAM-1.

RESULTS

In comparison to controls, sLFA-3 levels were elevated in patients with liver cirrhosis due to autoimmune liver disease (p < 0.0001) and viral liver disease (p = 0.001), but not in patients with alcoholic cirrhosis. Increased sLFA-3 levels were also found in patients with hepatocellular carcinoma and liver cirrhosis. However, sLFA-3 was not significantly elevated in sera from patients with autoimmune liver disease, viral liver disease, and hepatocellular carcinoma without concomitant liver cirrhosis. No difference was found between arterial and hepatic venous serum levels of sLFA-3 and sICAM-1. sLFA-3 levels correlated positively with aspartate transaminase, alkaline phosphatase, bilirubin, sICAM-1, and inversely with albumin and cholinesterase.

CONCLUSIONS

Taken together, sLFA-3 serum concentrations of patients with liver cirrhosis due to autoimmune liver disease or viral liver disease and of patients with hepatocellular carcinoma and cirrhosis are significantly increased compared to controls. Elevated sLFA-3 and sICAM-1 levels might reflect the generalized inflammation in cirrhosis and by interference with cell-cell interactions sICAM-1 and sLFA-3 may limit the extent of inflammation.

Serum and ascitic levels of soluble intercellular adhesion molecule-1 in patients with alcoholic liver cirrhosis: relation to biochemical markers of disease activity and alcohol intake

The overexpression of intercellular adhesion molecule-1 (ICAM-1) has been shown to be involved in the pathogenesis of various necroinflammatory diseases, including alcoholic hepatitis. Shedding of this molecule from cell surfaces results in a circulating form, soluble ICAM-1 (sICAM-1). In this work, the serum and ascitic concentrations of sICAM-1 were studied in relation to clinical and laboratory data in patients with alcoholic liver cirrhosis of different disease activities. Elevated circulating concentrations of this adhesion molecule were found in all cirrhotic patients, the highest in those with superimposed severe alcoholic hepatitis, and the levels in regularly drinking cirrhotics without severe alcoholic hepatitis were likewise significantly higher than in those who had stopped drinking. The serum sICAM-1 concentration was best related to the serum AST activity, and also exhibited significant correlations with the prothrombin activity, serum bilirubin, albumin, peripheral leukocyte count. Maddrey's discriminant function value, Child grading, and antecedent alcohol consumption. Multivariate regression analysis revealed that the serum AST and prothrombin activities were independent predictors of the circulating sICAM-1 concentration. The concentration of sICAM-1 in the uninfected ascitic fluid of cirrthotics was about seven times lower than that in the serum; the ratio of its ascitic and serum levels was lower than that of the ascitic and serum total protein concentrations. These data contradict a significant intraperitoneal production of the molecule. It is concluded that the serum sICAM-1 level may be useful as a marker for the current disease activity (the severity of underlying acute necroinflammatory reactions) in alcoholic liver cirrhosis.

DR human leukocyte antigens and disease severity in chronic hepatitis C

BACKGROUND/AIMS

Immune mechanisms may modulate disease severity in chronic hepatitis C and the DR human leukocyte antigens may affect these mechanisms. Our aims were to evaluate the association between the DR antigens and disease severity at presentation and to seek correlation between these antigens, disease severity and autoantibodies in this condition.

METHODS

Sixty-four patients were assessed prospectively and classified as having mild, moderate and severe disease by clinical, laboratory and histologic criteria. Fourteen DR antigens were determined by restriction fragment length polymorphism or polymerase chain reaction-sequence specific primers. Eighty normal subjects were typed in a similar fashion.

RESULTS

Patients with mild (16), moderate (32) and severe (16) disease at presentation were indistinguishable from each other and from normal subjects by the frequencies of each DR antigen. Subsets of patients with different laboratory and histological findings had DR frequencies comparable to those without these findings and to those of normal subjects. Patients with autoantibodies and/or concurrent immunologic diseases had mild (19% versus 32%, p = 0.4), moderate (50% versus 50%) and severe (31% versus 18%, p = 0.4) disease as commonly as other patients. The frequencies of the DR antigens were similar in each category of disease severity. Patients with autoimmune features differed from patients without these features (3% versus 32%, p = 0.002) and normal subjects (3% versus 25%, p = 0.003) by having a lower frequency of HLA DR1.

CONCLUSIONS

The DR antigens are not associated with any index of disease severity at presentation. Immunologic manifestations do not identify patients with a different disease severity or a distinctive genetic predisposition for disease activity. The presence of DR 1 is associated with a lower frequency of immune manifestations.

Serum levels of soluble intercellular adhesion molecule-1 and soluble vascular cell adhesion molecule-1 in liver disease, and their changes by treatment with interferon

Serum levels of soluble intercellular adhesion molecule-1 (sICAM-1) and soluble vascular cell adhesion molecule-1 (sVCAM-1) were measured by an enzyme-linked immunosorbent assay in patients with chronic hepatitis (n = 57), liver cirrhosis (n = 19) and hepatocellular carcinoma (n = 33). Serum levels of sICAM-1 and sVCAM-1 were significantly higher in liver disease than those in controls (P < 0.0001 and P < 0.0005, respectively). A total of 22 patients with chronic hepatitis C were treated with interferon. Pretreatment levels of sICAM-1 and sVCAM-1 were not significantly different between complete responders and non-responders. In complete responders, serum sICAM-1 and sVCAM-1 levels 1 year after interferon treatment significantly decreased compared to the pretreatment levels (P < 0.005 and P < 0.05, respectively). Post-treatment levels of sICAM-1 and sVCAM-1 in complete responders were also significantly lower than those in non-responders (P < 0.005 and P < 0.05, respectively). This suggests that monitoring soluble adhesion molecules might be useful in the follow-up of patients with liver disease.

Increased frequency of HLA DR13 in hepatitis C virus carriers with persistently normal ALT levels

The aim of this study was to clarify the relationship between human leukocyte antigen DR allele distribution and the degree of liver cell injury of hepatitis C virus (HCV) carriers in Japan. The subjects, 68 HCV carriers, were divided into two groups according to the laboratory data and liver histology. Those in the asymptomatic carrier group (n = 19) had normal ALT levels persistently for 8-153 months (mean 25.7 months) and were diagnosed histologically as normal liver, nonspecific reactive hepatitis or chronic persistent hepatitis. Those in the chronic active hepatitis group (n = 49) had elevated ALT levels and were diagnosed histologically with chronic active hepatitis. The human leukocyte antigen DR alleles of all subjects were defined using the polymerase chain reaction restriction fragment length polymorphism method. The expression of human leukocyte antigen class I antigen and intercellular adhesion molecule 1 on the hepatocyte membrane were also examined in 14 patients from each group using an indirect immunohistochemical method. The frequency of DR13 (42.1%) in the asymptomatic carrier group was significantly higher (Pc < 0.003) than that of the chronic active hepatitis group (4.1%). There were no significant differences for the other DR alleles. The frequencies of expression of human leukocyte antigen class I antigen and intercellular adhesion molecule 1 on the hepatocyte membrane of the asymptomatic carrier group were significantly less than those of the chronic hepatitis group (64% vs. 100% P < 0.05, 29% vs. 71% P < 0.05, respectively), although there was no significant difference in the serum HCV-RNA titer between the two groups (10(6.4 +/- 1.1) vs. 10(6.5 +/- 0.7) copies/mL). These results demonstrate that the cellular immune response of the asymptomatic carrier group is less activated than the response of the chronic active hepatitis group and that HLA DR13 may be closely associated with this low activity of hepatitis among HCV carriers.

The use of immunohistochemistry for evaluating the liver

Immunohistochemistry has been utilized in recent years primarily for diagnosis of infectious diseases of the liver, especially in humans. The utility of immunohistochemistry has extended to experimental and toxicologic pathology in a variety of areas: identification of cell phenotype, cell receptors, cytokine and chemikine production, and functional cell changes such as enzyme induction. In addition, markers for experimental carcinogenesis studies are detectable by immunohistochemical changes as well as novel antigen induction such as placental glutathione-S-transferase, oncofetal proteins, oncogene products, and typing of neoplasms. Immunohistochemistry is also used to detect the origin and function of various cell types in developmental and toxicity studies. Careful use of immunohistochemical procedures in conjunction with routine pathology and molecular techniques enhance the ability of the toxicologic pathologist to diagnose unique conditions and to understand mechanisms of lesion development.

Intercellular adhesion molecule-1

The intercellular adhesion molecule (ICAM) 1 is an Ig-like cell adhesion molecule expressed by several cell types, including leukocytes and endothelial cells. It can be induced in a cell-specific manner by several cytokines, for example, tumor necrosis factor-alpha, interleukin-1, and interferon-gamma, and inhibited by glucocorticoids. Its ligands are the membrane-bound integrin receptors LFA-1 and Mac-1 on leukocytes, CD43, the soluble molecule fibrinogen, the matrix factor hyaluronan, rhinoviruses, and Plasmodium falciparum malaria-infected erythrocytes. ICAM-1 expression is predominantly transcriptionally regulated. The ICAM-1 promoter contains several enhancer elements, among them a novel kappa B element which mediates effects of 12-O-tetradecanoylphorbol-13-acetate, interleukin-1, lipopolysaccharide, tumor necrosis factor-alpha, and glucocorticoids. Expression regulation is cell specific and depends on the availability of cytokine/hormone receptors, signal transduction pathways, transcription factors, and posttranscriptional modification. ICAM-1 plays a role in inflammatory processes and in the T-cell mediated host defense system. It functions as a costimulatory molecule on antigen-presenting cells to activate MHC class II restricted T-cells, and on other cell types in association with MHC class I to activate cytotoxic T-cells. ICAM-1 on endothelium plays an important role in migration of (activated) leukocytes to sites of inflammation. ICAM-1 is shed by the cell and detected in plasma as sICAM-1. Regulation and significance of sICAM-1 are as yet unclear, but sICAM-1 is increased in many pathological conditions. ICAM-1 may play a pathogenetic role in rhinovirus infections. Derangement of ICAM-1 expression probably contributes to the clinical manifestations of a variety of diseases, predominantly by interfering with normal immune function. Among these are malignancies (e.g., melanoma and lymphomas), many inflammatory disorders (e.g., asthma and autoimmune disorders), atherosclerosis, ischemia, certain neurological disorders, and allogeneic organ transplantation. Interference with ICAM-1 leukocyte interaction using mAbs, soluble ICAM-1, antisense ICAM-1 RNA, and in the case of melanoma mAb-coupled immunotoxin, may offer therapeutic possibilities in the future. Integration of knowledge concerning membrane-bound and soluble ICAM-1 into a single functional system is likely to contribute to elucidating the immunoregulatory function of ICAM-1 and its pathophysiological significance in various disease entities.

Significance of human leukocyte antigens DR3 and DR4 in chronic viral hepatitis

Immune mechanisms have been implicated in chronic viral hepatitis, and these may be influenced by genetic factors. To determine if disease severity in chronic viral hepatitis is associated with the human leukocyte antigens DR3 and/or DR4, 109 patients were evaluated prospectively. The frequencies of DR3 and DR4 in these patients were compared to those in 80 normal subjects. Patients with DR3 and/or DR4 had the same occurrence of severe disease as patients with other DR antigens (21% versus 30%, P = 0.3). Patients with DR3, however, had higher serum gamma globulin and immunoglobulin G levels than patients with DR4 and a greater frequency of severe disease (36% vs 12%, P = 0.046). Patients with DR4 had concurrent immunologic diseases more commonly than patients with DR3 (44% vs 9%, P = 0.005) and patients with other DR antigens (44% vs 9%, P = 0.0002). Patients with DR4 but not DR3 had severe disease less frequently than other patients (9% vs 31%, P = 0.02). The frequencies of DR3 in patients with severe disease (37% vs 18%, P = 0.06) and DR4 in patients without severe disease (44% vs 30%, P = 0.07) were different than those in normal subjects but not to a statistically significant level. We conclude that patients with DR3 and DR4 have different clinical and laboratory findings and disease severity. Patients with DR4 have milder disease than patients with other DR antigens. Disease severity, however, is not closely associated with DR3 or DR4.