Mechanism of restoration of immune responses of patients with chronic hepatitis B during lamivudine therapy: increased antigen processing and presentation by dendritic cells.

Restoration of host immunity has been reported in patients with chronic hepatitis B (CHB) after treatment with lamivudine; however, the underlying mechanisms of this treatment have not been determined. This study examined the role of antigen-presenting dendritic cells (DC) in restoration of host immunity. Circulating DC were isolated from peripheral blood of 23 patients with CHB before and 1, 3, and 12 months after starting lamivudine therapy. The non-antigen-specific proliferation of DC was assessed in allogenic mixed leucocyte reaction. Dendritic cells were cultured with hepatitis B surface antigen (HBsAg) to prepare HBsAg-pulsed DC. Proliferative capacity and production of interleukin (IL)-12 and interferon (IFN)-γ of HBsAg-pulsed DC were evaluated. Circulating unpulsed DC and HBsAg-pulsed DC showed significantly higher levels of T-cell proliferation capacities 1 month after lamivudine therapy compared to proliferation levels before therapy (P<0.05). HBsAg-pulsed DC also produced significantly higher levels of IL-12 and IFN-γ with lamivudine therapy compared to levels before therapy (P<0.05). HBsAg-pulsed DC from lamivudine-treated patients induced proliferation of T cells of patients with CHB in an antigen-specific manner (P<0.05). However, T-cell stimulatory capacity of DC did not increase significantly 3 and 12 months after lamivudine therapy compared to 1 month after lamivudine therapy. Immune restoration as a result of lamivudine therapy is regulated at least in part by activation of DC. However, progressive activation of DC was not seen as treatment duration progressed, indicating the limitations of this mechanism of viral clearance.

Safety and immunogenicity of hepatitis B surface antigen-pulsed dendritic cells in patients with chronic hepatitis B.

The immune modulator capacity of antigen-pulsed dendritic cells (DC) has been documented in patients with cancers and in animal models of chronic viral infections. Cancer antigen-pulsed DC are now used for treating patients with cancer. But viral antigen-pulsed DC are not used in chronic viral-infected patients because safety of antigen-pulsed DC has not been evaluated in these patients. DC were isolated from human peripheral blood mononuclear cells by culturing with human-grade granulocyte-macrophage colony stimulating factor and interleukin-4. Human blood DC were cultured with hepatitis B surface antigen (HBsAg) for 8h to prepare HBsAg-pulsed DC. After immunogenicity assessment of HBsAg-pulsed DC in vitro, five million HBsAg-pulsed DC were administered intradermally to five patients with chronic hepatitis B (CHB) 1-3 times. HBsAg-pulsed DC were immunogenic in nature because they produced significantly higher levels of interleukin-12 and interferon-γ compared to unpulsed DC (P<0.05). Also, HBsAg-pulsed DC induced proliferation of HBsAg-specific T lymphocytes in vitro. CHB patients injected with HBsAg-pulsed DC did not exhibit generalized inflammation, exacerbation of liver damage, abnormal kidney function, or features of autoimmunity. Administration of HBsAg-pulsed DC induced anti-HBs in two patients and HBsAg-specific cellular immunity in 1 patient. This is the first study about preparation of antigen-pulsed DC using human consumable materials for treating patients with CHB. Because HBsAg-pulsed DC were safe for all patients with CHB and had immune modulation capacity in some patients, phase I and phase II clinical trials with antigen-pulsed DC in CHB and other chronic infections are warranted.

Impaired functional capacities of liver dendritic cells from murine hepatitis B virus (HBV) carriers: relevance to low HBV-specific immune responses.

The chronic hepatitis B virus (HBV) carrier exhibits ongoing replication of HBV and expresses abundant amounts of HBV-related antigens in the liver. However, HBV-specific immune responses are either absent or narrowly focused in these subjects. With the postulation that impaired functional abilities of liver dendritic cells (DCs) might be responsible for this, we assessed the functions of liver DCs in HBV transgenic mice (HBV-TM), an animal model of the HBV carrier state. Liver DCs were isolated from normal C57BL/6 mice and HBV-TM without the use of cytokines or growth factors. Lymphoproliferative assays were conducted to evaluate the ability of liver DCs to induce the proliferation of allogenic T lymphocytes and hepatitis B surface antigen (HBsAg)-enriched T lymphocytes. Liver DCs were stimulated with viral and bacterial products to assess their cytokine-producing capacities. In comparison to liver DCs from normal C57BL/6 mice, liver DCs from HBV-TM exhibited significantly decreased T cell proliferation-inducing capacities in allogenic mixed leucocyte reaction (P <0.05) and HBsAg-enriched T lymphocytes proliferation assays (P <0.05). Liver DCs from HBV-TM produced significantly lower levels of interleukin-12p70, tumour necrosis factor-alpha, interferon-gamma, and interleukin-6 (P <0.05) compared to liver DCs from normal C57BL/6 mice. This study provides evidence that liver DCs from HBV-TM had impaired ability to induce both innate and adaptive immune responses. This might account for a weak and almost undetectable HBV-specific immune response in chronic HBV carriers. This inspires hope that up-regulation of the functions of liver DCs in situ may have therapeutic implications in chronic HBV carriers.

Decreased interferon-alpha production and impaired T helper 1 polarization by dendritic cells from patients with chronic hepatitis C.

Patients with chronic hepatitis C (CHC) are unable to prime and maintain vigorous T cell responses that are initiated during the acute phase of hepatitis C virus (HCV) infection. As dendritic cells (DCs) induce and regulate both innate and adaptive immune responses, the aim of this study was to analyse two critical functions of DCs: firstly, production of interferon (IFN)-alpha and, secondly, polarization of T helper 1 lymphocytes. The frequencies of plasmacytoid DC (PDC) and myeloid DC (MDC) were estimated in 63 patients with CHC and 34 normal controls using four-colour flow cytometry. Circulating DCs were isolated from peripheral blood of CHC patients (n = 10) and normal controls (n = 10). These DCs were cultured with herpes simplex virus-1 to evaluate their capacity to produce IFN-alpha. The capacity of DCs to induce polarization of autologous naive CD4(+) T lymphocytes to IFN-gamma-producing effector T lymphocytes was also assessed. The frequencies of PDCs producing intracellular IFN-alpha (P < 0.01) and the levels of IFN-alpha in culture supernatant of PDCs (P < 0.01) were significantly lower in patients with CHC compared to those of normal controls. The numbers of MDC were significantly lower in patients with CHC (8.2 (6.0)/ micro l, median (interquartile range), n = 63) compared to normal control (11.7 (7.8)/ micro l, n = 34) (P < 0.01). Moreover, DCs from patients with CHC induced significantly lower numbers of IFN-gamma-producing effector T lymphocytes compared to that of controls (P < 0.01). This study indicates that the low IFN-alpha-producing capacity and impaired T helper 1 polarization ability of DCs from patients with CHC might be responsible for the typical low anti-HCV immune responses in these patients.

Isolation and functional analysis of circulating dendritic cells from hepatitis C virus (HCV) RNA-positive and HCV RNA-negative patients with chronic hepatitis C: role of antiviral therapy.

Hepatitis C virus (HCV) RNA has been localized in antigen-presenting dendritic cells (DCs) from patients with chronic hepatitis C (CHC). DCs from patients with CHC also exhibit impaired functional capacities. However, HCV RNA in DCs and functional impairment of DCs in CHC might be independent or interrelated events. Moreover, the impact of antiviral therapy on the functions of DCs in CHC is not well documented. In order to address these issues, we took advantage of antiviral therapy in these patients. Ten patients with CHC, expressing HCV RNA in circulating DCs, became negative for HCV RNA in circulating DCs after therapy with interferon-alpha and ribavirin for 4 weeks. The functions of DCs from HCV RNA+ patients (isolated before antiviral therapy) and HCV RNA- patients (isolated 4 weeks after antiviral therapy) were compared in allogenic mixed leucocyte reactions. In comparison to circulating DCs from normal control subjects, DCs from HCV RNA+ patients had a significantly decreased capacity to stimulate allogenic T lymphocytes (P < 0.01) and produce interleukin-12 (P < 0.05). However, the allostimulatory capacity of circulating DCs from HCV RNA- patients was several-fold higher compared to that of HCV RNA+ DCs from the same patient. DC from HCV RNA- patients also produced significantly higher levels of interleukin-12 compared to HCV RNA+ DCs from the same patient (P < 0.01). Taken together, this study is the first to provide experimental evidence regarding the impact of HCV RNA and antiviral therapy on the function of DCs in patients with CHC.

Macrophage migration inhibitory factor activates antigen-presenting dendritic cells and induces inflammatory cytokines in ulcerative colitis.

The level of macrophage migration inhibitory factor (MIF) and the functions of dendritic cells (DC) are up-regulated in the peripheral blood, and the numbers of MIF-expressing cells and mature DC are increased at the colonic mucosa from patients with ulcerative colitis (UC). However, a functional relationship between MIF and DC, and the role of MIF in the pathogenesis of UC, are not clear. In this study, we showed that a pure population of peripheral blood DC is a new and still unknown source of MIF. DC from UC patients produced significantly higher levels of MIF (17 x 5 +/- 9 x 8 ng/ml, n = 10) compared with patients with Crohns disease (CD) (4 x 6 +/- 2 x 5 ng/ml, n = 5, P< 0 x 01) and control subjects (5 x 0 +/- 2 x 6 ng/ml, n = 10, P< 0 x 01). A double immunofluorescence study revealed the expression of MIF by CD83-positive mature DC at the colonic mucosa from UC patients. Blood DC treated with high amounts of MIF (500 ng/ml) showed a significantly higher stimulatory capacity (43287 +/- 5998 CPM, n = 5) in an allogenic mixed leucocyte reaction compared with untreated DC (27528 +/- 8823 CPM, n = 5, P< 0 x 05). Study of intracellular cytokine expression showed that MIF induced significant levels of interleukin (IL)-1 and IL-8 in monocytes and DC from UC and CD patients. These results showing the capacity of MIF to induce increased functional capacity of DC, and to produce IL-1 and IL-8 from monocytes and DC, indicate a role of MIF in the induction and/or perpetuation of the inflammatory environment in UC.

Increased serum levels of macrophage inflammatory protein-3alpha in chronic viral hepatitis: prognostic importance of macrophage inflammatory protein-3alpha during interferon therapy in chronic hepatitis C.

Increased infiltration of lymphocytes and induction of damage and destruction of hepatocytes by these lymphocytes are characteristic features of chronic viral hepatitis. As chemokines attract lymphocytes to inflamed tissues, we studied macrophage inflammatory protein (MIP)-3alpha, a CC chemokine, in chronic viral hepatitis. The levels of MIP-3alpha were measured in the sera from 40 patients with chronic viral hepatitis and 30 control subjects by an enzyme-linked immunosorbent assay (detection limit of MIP-3alpha=7.8 pg/mL). The kinetics of MIP-3alpha were checked during interferon (IFN) therapy in 25 patients. The levels of MIP-3alpha in the sera were significantly higher in patients with chronic viral hepatitis (39.0 +/- 28.9 pg/mL) than control subjects (15.6 +/- 4.9 pg/mL; P < 0.0001) and in patients with severe (49.6 +/- 49.2 pg/mL) and moderate degree of hepatitis (50.9 +/- 27.1 pg/mL) than in mild disease (16.0 +/- 6.8 pg/mL; P < 0.05). A significant correlation was seen among serum MIP-3alpha levels with the levels of alanine aminotransferase (r=0.509, P < 0.0001), aspartate aminotransferase (r=0.505, P < 0.0001), and degrees of activity of hepatitis (r=0.592, P < 0.0001) and interface hepatitis (r=0.419, P=0.0066). The levels of MIP-3alpha were significantly increased in patients with hepatitis C 2 weeks after the start of therapy in IFN-responders, but, remained almost unchanged in IFN-nonresponders. These findings might be important not only for the understanding of immunoptahogenesis of hepatocellular damage in chronic hepatitis (CH) patients but also for a therapeutic strategy to control the local immune response in the liver. A prognostic value of MIP-3alpha during IFN therapy in patients with chronic hepatitis C is also shown.

Antigen-presenting cells at the liver tissue in patients with chronic viral liver diseases: CD83-positive mature dendritic cells at the vicinity of focal and confluent necrosis.

Although defective functions of peripheral blood or splenic antigen-presenting cells (APCs) are implicated in the pathogenesis of persistent infection in murine and human hepatitis B virus (HBV) and hepatitis C virus (HCV)-carriers, little is known regarding liver-infiltrating APCs in patients with chronic liver diseases. Using immunohistochemical methodology and antigen retrieval technique, we have detected APCs such as HLA DR-positive cells, interdigitating cells (IDCs) and CD83-positive mature and activated dendritic cells (DCs) at the liver specimens from 39 patients with chronic hepatitis (CH) and 10 patients with liver cirrhosis (LC). All 3 types of APCs were detected at the portal areas in both CH and LC, the most abundant being the HLA DR-positive APCs. CD83-positive, mature and activated DCs were detected in patients with CH around the areas of focal and confluent necrosis at the liver parenchyma in close association with T cells. The localization of CD83-positive mature and activated DCs at the liver tissues from patients with CH warrants further study about the role of these DCs in the induction of hepatocellular damage. This may also help to design DC-based therapy for patients with chronic liver diseases.

Geographic distribution of hepatitis B virus (HBV) genotype in patients with chronic HBV infection in Japan.

The geographic distribution of hepatitis B virus (HBV) genotypes in Japan and its clinical relevance are poorly understood. We studied 731 Japanese patients with chronic HBV infection. HBV genotype was determined by the restriction fragment length polymorphism (RFLP) method after polymerase chain reaction (PCR). Of the 720 patients with positive PCR, 12 (1.7%) were HBV genotype A, 88 (12.2%) were genotype B, 610 (84.7%) were genotype C, 3 (0.4%) were genotype D, and 7 (1.0%) were of mixed genotype. Over 94% of patients on the Japanese mainland had genotype C, while 60% of the patients on Okinawa, the most southern islands, and 22.9% in the Tohoku area, the northern part of the mainland, harbored genotype B. Compared with genotype C patients, genotype B patients were older (53.6 to 42.2 years; P <.01), had a lower rate of positive hepatitis B e antigen (HBeAg) (18.4% to 50.6%; P <.01), and a lower level of serum HBV DNA (5.02 to 5.87 log genome equivalents (LGE)/mL; P <.01). The mean age of the genotype B patients with hepatocellular carcinoma was 70.1 +/- 9.2 years, compared with 55.2 +/- 9.7 of genotype C patients (P <.01). These results indicate that genotypes C and B are predominant in Japan, and there are significant differences in geographic distribution and clinical characteristics among the patients with the different genotypes.

Macrophage migration inhibitory factor in hepatocellular carcinoma and liver cirrhosis; relevance to pathogenesis.

The levels of macrophage migration inhibitory factor (MIF), a proinflammatory and carcinogenic cytokine, were significantly higher in the sera from patients with hepatocellular carcinoma (HCC; 25.6+/-15.3 ng/ml, n=55) and liver cirrhosis (LC; 18.9+/-10.7 ng/ml, n=26) compared with sera from patients with gastrointestinal cancer (6.8+/-7.5 ng/ml, n=29) and normal controls (5.6+/-1.2 ng/ml, n=45; P<0.01). Hepatocytes from patients with LC and HCC, but not from chronic hepatitis, expressed very high levels of MIF. A possible association between overexpression of MIF and hepatocarcinogenesis is suggested.

Dendritic cells and chronic hepatitis virus carriers.

Many individuals infected with hepatitis B virus (HBV) and hepatitis C virus (HCV) are unable to clear these viruses following an acute infection and become chronically infected. There are more than 400 million HBV and HCV carriers in the world and a considerable number of these patients would eventually develop more severe complications like liver cirrhosis and hepatocellular carcinoma. It is not clearly known how an individual develops a chronic hepatitis virus carrier state; however, a defective immune response of the host is thought to play a critical role in the underlying pathogenetic mechanism. On the other hand, dendritic cells (DCs), the most potent antigen-presenting cells, are widely distributed in both lymphoid and nonlymphoid tissues. Recognition of the microbes or microbial antigens by DCs is one of critical events for the initiation of an immune response. DCs also play a cardinal role during the progression and termination of an immune response. The aim of this overview is to provide information regarding the role of DCs in the pathogenesis of chronic hepatitis due to HBV and HCV in humans and in animal models of HBV and HCV carrier states. First, we summarize our current understanding of the pathogenesis of hepatitis virus carrier states and also of general properties of DCs. Next, we discuss the data on the phenotypes and functions of DCs in both human and murine HBV and HCV carriers. We also discuss vaccine therapy in murine HBV carriers because activation of DCs due to vaccination-initiated HBsAg-specific immune responses in HBV transgenic mice (HBV-Tg), which in turn resulted in complete clearance of hepatitis B surface antigen and hepatitis B e antigen and decreased levels of HBV DNA in some HBV-Tg. Finally, we discuss the extracted questions and future research directions.

Peripheral blood T-cell responses to pyruvate dehydrogenase complex in primary biliary cirrhosis: role of antigen-presenting dendritic cells.

Patients with primary biliary cirrhosis (PBC) are usually characterized by the presence of antibody to pyruvate dehydrogenase complex (PDC) in the sera and PDC-specific T cells in the liver. However, most of the patients with PBC do not show peripheral blood T cells response to PDC. In this study, we re-evaluated the peripheral blood T cell responses to PDC in PBC using antigen-presenting dendritic cells (DCs). Twenty-four patients with PBC (AMA-positive: 16; AMA-negative: 8) and 13 normal controls were enrolled in the study. Peripheral blood mononuclear cells (PBMC) and highly enriched populations of T cells were stimulated with either only PDC or DCs plus PDC or PDC-pulsed DC plus PDC. Antibodies to different components of PDC were estimated by an immunoblotting technique. PBMC from only one out of ten AMA-positive PBC patients proliferated when cultured with only PDC. However, peripheral blood T cells from ten out of ten AMA-positive PBC patients and three out of ten AMA-negative PBC patients, but none of the five normal controls showed PDC-specific proliferation when cultured with PDC-pulsed DCs. Two of these three AMA-negative PBC patients, although negative for AMA, were positive for antibodies to other components of PDC. PDC-specific T cells are present in the peripheral blood from most of the patients with PBC. This is the first report on the effectiveness of antigen-pulsed DCs for the elucidation of autoantigen-specific immune response in human autoimmune diseases.

Increased serum levels of macrophage migration inhibitory factor in alcoholic liver diseases and their expression in liver tissues.

OBJECTIVES: To study the role of macrophage migration inhibitory factor (MIF) in the pathogenesis of alcoholic liver diseases. DESIGN AND METHODS: The levels of MIF in the sera were estimated by an enzyme-linked immunosorbent assay in 13 patients with alcoholic hepatitis (ALH), 9 patients with alcoholic cirrhosis (ALC) and 26 normal controls. MIF was localized in the liver specimens by immunohistochemistry. RESULTS: The mean levels of MIF in the sera were significantly higher in ALH and ALC compared with the normal controls (p < 0.05). Serial observations revealed a relationship between serum MIF levels and the serum transaminase levels. MIF was expressed by the hepatocytes and by the infiltrating cells around the site of accumulation of neutrophils and ballooned hepatocytes in ALH. CONCLUSIONS: This is the first report on MIF in human alcoholic liver diseases, and the data suggest that MIF may be related to abnormal cytokine homeostasis in ALH.

Noninvasive diagnosis of the degree of hepatic fibrosis using ultrasonography in patients with chronic liver disease due to hepatitis C virus.

BACKGROUND: Chronic liver disease is characterized by progressive hepatic fibrosis and changes in hepatic haemodynamics. This study has addressed the possibility of a noninvasive diagnosis of the degree of hepatic fibrosis by evaluating the velocity of blood in the hepatic vasculature. Materials and methods The maximum velocity of blood at the portal vein and hepatic artery was measured in 80 patients with chronic liver diseases (19 with liver cirrhosis; 61 with chronic hepatitis) and in 20 normal volunteers by Doppler ultrasonography. The arterio-portal ratio (A/P ratio) was calculated by dividing the maximum velocity of blood (Vmax) in the hepatic artery with the Vmax in the portal vein. Multivariate analysis was used to disclose the independent predictors of the degree of hepatic fibrosis. RESULTS: The levels of A/P ratio were significantly higher in patients with liver cirrhosis (LC) compared to those with chronic hepatitis (CH) and normal controls. Probit analysis revealed that the value of A/P ratio at which CH becomes LC was A/P >or= 3.5. The levels of A/P ratio were also significantly higher in patients with severe fibrosis compared with mild (P < 0.0001) and moderate (P < 0.0001) fibrosis. Multivariate analysis disclosed right A/P ratio (P = 0.0001), left A/P ratio (P = 0.013), and platelet counts (P = 0.0172), as the only independent predictors of the degree of hepatic fibrosis. CONCLUSIONS: A/P ratio may be used for the noninvasive diagnosis of the degree of hepatic fibrosis in patients with chronic liver diseases.

Mechanisms of alcoholic liver disease: cytokines.

This article represents the proceedings of a workshop at the 2000 ISBRA Meeting in Yokohama, Japan. The chair was Manuela G. Neuman. The presentations were (1) New aspects of hepatic fibrosis, by D. A. Brenner; (2) Cellular immune response in hepatitis C models, by B. Rehermann; (3) The role of interleukin-10 in acute alcoholic hepatitis, by J. Taieb, S. Chollet-Martin, M. Cohard, J. J. Garaud, and T. Poynard; (4) Cytokine-mediated apoptosis in vitro, by M. G. Neuman; (5) Signaling for apoptosis and repair in vitro, by G. G. Katz, R. G. Cameron, N. H. Shear, and M. G. Neuman; (6) Interferons activate the P42/44 mitogen-activated protein kinase and Janus Kinase signal transducers and activation of transcription (JAK-STAT) signaling pathways in hepatocytes: Differential regulation by acute ethanol via a protein kinase C-dependent mechanism, by B. Gao; (7) Genetic polymorphisms of interleukin-1 in association with the development of Japanese alcoholic liver disease, by M. Takamatsu, M. Yamauchi, M. Ohata, S. Saito, S. Maeyama, T. Uchikoshi, and G. Toda; and (8) Increased levels of macrophage migration inhibitory factor in sera from patients with alcoholic liver diseases, by T. Kumagi, S. M. F. Akbar, M. Abe, K. Michitaka, N. Horiike, and M. Onji.

Mechanism and therapeutic potential of DNA-based immunization against the envelope proteins of hepatitis B virus in normal and transgenic mice.

Two plasmid DNA vectors, pCAGGS(S) encoding the genes of the major envelope protein of hepatitis B virus (HBV), and pCAGGS(S + preS2) encoding the genes of the middle envelope protein were used to study the mechanism and therapeutic potential of DNA-based immunization. Injection of these plasmids into the regenerating bilateral tibialis anterior muscle (TA) of normal C57BL/6 mice induced hepatitis B surface antigen (HBsAg)-specific humoral and cellular immune responses. Seventy-two hours after injection of pCAGGS(S), infiltrating cells including antigen-presenting dendritic cells (DC) were localized around the injection site and HBsAg was expressed by both muscle cells and infiltrating cells. Spleen DC from the mice were exposed to HBsAg for up to 32 weeks after a single injection of pCAGGS(S), because these DC induced the proliferation of HBsAg-specific memory lymphocytes in culture without exogenous HBsAg. A single injection of pCAGGS(S) or pCAGGS(S + preS2) resulted in the clearance of HBsAg in 28 out of 30 HBV-transgenic (Tg) mice. In contrast, more than 7 monthly injections of an HBsAg-based vaccine were required for the clearance of HBsAg in 6 out of 29 HBV-Tg mice. Infiltrating DC at the DNA vaccine injection site may have a role in initiating HBsAg-specific immune response, whereas the persistence of HBsAg exposed spleen DC may contribute to long-lasting immunity. This study also suggested that DNA-based vaccines may be a potent tool for treating chronic HBV carriers.

Induction of cytokine production and proliferation of memory lymphocytes by murine liver dendritic cell progenitors: role of these progenitors as immunogenic resident antigen-presenting cells in the liver.

BACKGROUND/AIMS: Many pathogenic organisms, including hepatotrophic viruses enter the liver and induce an immune response, but there is little information about the immunogenic resident antigen-presenting cells. The aim of this study was to determine whether dendritic cells in the liver are immunogenic antigen-presenting cells. METHODS: Liver dendritic cell progenitors were enriched from normal C57BL/6 mice by culturing non-parenchymal cells with granulocyte-macrophage colony stimulating factor for 7 days. Then the surface antigen (MHC class II, CD86) expression, endocytic capacity, ability to induce cytokines, and the proliferation of memory lymphocytes were investigated. RESULTS: Freshly enriched liver dendritic cell progenitors exhibited an immature phenotype and failed to stimulate allogenic T cells. However, the progenitors underwent maturation following exposure to antigens such as hepatitis B surface antigen and keyhole limpet hemocyanin. The progenitors then became strong stimulators of allogenic T cells, supported the production of interleukin-12 and interferon-gamma, and induced the proliferation of antigen-specific memory lymphocytes. CONCLUSIONS: Dendritic cell progenitors are immunogenic resident antigen-presenting cells in the liver. Simultaneous investigation of both tolerogenic and immunogenic resident antigen-presenting cells may provide insights into the pathogenesis of persistent infection and autoimmmune diseases of the liver.

The CD81 expression in liver in hepatocellular carcinoma.

The expression of CD81, a cell receptor for hepatitis C virus, was examined on cancer cells in hepatocellular carcinoma (HCC) C (n=29) to clarify its clinical role. CD81 was expressed on hepatocyte membrane in non-tumor portions in all patients, however, this was not stained on the cancer cell membranes in 6 of 29. Reverse transcriptase-PCR revealed that CD81 gene expression was not detected in the tumorous portions in 3 of 7 samples. The loss of CD81 was prominent in poorly differentiated HCC (5 of 8) and extrahepatic metastasis patients (6 of 8). The loss of CD81 is associated with differentiation and metastasis of HCC.

An autopsy case of primary biliary cirrhosis with severe interstitial pneumonia.

A 74-year-old woman was admitted to our hospital because of interstitial pneumonia. She had a 14-year history of primary biliary cirrhosis (PBC) diagnosed histologically, with a positive test for anti-mitochondrial antibodies and elevated biliary enzyme activity. She also had a 7-year history of rheumatoid arthritis and a 26-year history of Sjögren's syndrome. Though the symptoms of these complications improved, the interstitial pneumonia deteriorated very quickly and the patient died of respiratory failure due to acute exacerbation of interstitial pneumonia when the activity of PBC decreased. We report this case because it is relatively rare for PBC to be complicated by severe interstitial pneumonia, and it may offer insight into the etiology of these diseases.