Impaired dendritic cell function resulting from chronic undernutrition disrupts the antigen-specific immune response in mice.

We examined whether antigen-specific immune responses are lower in mice with protein energy malnutrition (PEM mice) compared with nourished (control) mice. The mechanisms underlying reduced antigen-specific immune responses of PEM mice were evaluated through analysis of the functional capacities of antigen-presenting dendritic cells (DC). PEM mice were produced by subjecting male C57BL/6 mice for 52 wk to a daily food intake equivalent to 70% of the mean amount consumed by the control mice that consumed food ad libitum. PEM mice and control mice were immunized with hepatitis B vaccine containing hepatitis B surface antigen (HBsAg) at 52 wk and humoral and cellular immune responses to HBsAg were evaluated at 58 wk. Lymphoproliferative assays were performed to assess the functional capacities of lymphocytes and DC. After 52 wk of food restriction, PEM mice had a 49% lower body weight than controls, almost no subcutaneous fat, severe muscle wasting, and atrophied spleen. All control mice developed antibodies to HBsAg (anti-HBs) in the sera and HBsAg-specific lymphocytes in the spleen as a result of immunization with the hepatitis B vaccine. PEM mice, however, were almost unresponsive to immunization with the hepatitis B vaccine. In PEM mice, the numbers of spleen DC, the T lymphocyte stimulatory capacities of DC, and their production of IL-12p70 and IFN-gamma was less than those of control mice (P < 0.05). We suggest that chronic undernutrition disrupts antigen-specific immune responses and that this disruption can be attributed at least in part to reduced frequencies and impaired functions of DC.

Clinical characteristics of autoimmune hepatitis in older aged patients.

BACKGROUND AND AIMS: Autoimmune hepatitis (AIH) is an inflammatory disease of the liver that usually develops in middle-aged women. However, due to the increasing aging of the population and better diagnostic facilities, AIH is now diagnosed in older patients as well. This analysis compared the clinical and pathologic characteristics of older and middle-aged patients with AIH. PATIENTS AND METHODS: Thirteen older patients with AIH (mean age, 75.0+/-5.3 years; range, 70-89 years) and 27 middle-aged patients (mean age, 51.3+/-5.8 years; range, 41-60 years) were included in this study. In addition, the use of different treatment regimens, including prednisolone therapy and ursodeoxycholic acid (UDCA), was examined. RESULTS: There were no significant differences in gender, complications of other autoimmune diseases, and liver function tests between groups. However, the degree of hepatic fibrosis was significantly higher in older patients compared with middle-aged patients (P<0.05). Four patients with AIH in the older age group were successfully managed by UDCA alone. CONCLUSION: This study shows that older patients with abnormal liver function should be checked for AIH. In addition, UDCA may be an effective drug for management of older patients with AIH.

Immune therapy including dendritic cell based therapy in chronic hepatitis B virus infection.

Hepatitis B virus (HBV) infection is a global public health problem. Of the approximately 2 billion people who have been infected worldwide, more than 400 million are chronic carriers of HBV. Considerable numbers of chronic HBV carriers suffer from progressive liver diseases. In addition, all HBV carriers are permanent source of this virus. There is no curative therapy for chronic HBV carriers. Antiviral drugs are recommended for about 10% patients, however, these drugs are costly, have limited efficacy, and possess considerable side effects. Recent studies have shown that immune responses of the host to the HBV are critically involved at every stage of chronic HBV infection: (1) These influence acquisition of chronic HBV carrier state, (2) They are important in the context of liver damages, (3) Recovery from chronic HBV-related liver diseases is dependent on nature and extent of HBV-specific immune responses. However, induction of adequate levels of HBV-specific immune responses in chronic HBV carriers is difficult. During the last one decade, hepatitis B vaccine has been administered to chronic HBV carriers as a therapeutic approach (vaccine therapy). The present regimen of vaccine therapy is safe and cheap, but not so effective. A dendritic cell-based therapeutic vaccine has recently been developed for treating chronic HBV infection. In this review, we will discuss about the concept, scientific logics, strategies and techniques of development of HBV-specific immune therapies including vaccine therapy and dendritic cell-based vaccine therapy for treating chronic HBV infection.

Expression of CD163 in the liver of patients with viral hepatitis.

CD163 is a marker of activated macrophages, and increased levels of soluble CD163 have been detected in sera obtained from patients with hepatitis. The aim of this study was to detect the expression of CD163 in the liver from patients with viral hepatitis. Frozen sections of liver specimens were obtained from 5 patients with acute viral hepatitis (AH) and from 23 patients with chronic viral hepatitis (CH). The expression of CD163 in the liver was determined immunohistochemically using monoclonal antibody to human CD163. Double immunostaining was done to assess those cell types that express CD163 in the liver. The frequencies of CD163-positive cells were significantly higher both in the portal areas and in the hepatic lobules in the liver of patients with AH compared to those with CH (p < 0.05). Double immunostaining revealed that most of the CD163-positive cells were macrophages and Kupffer cells, because they expressed CD68. The expression of CD163 was very low in endothelial cells and liver stellate cells. This study shows that macrophages are activated in hepatitis liver.

Early development of primary biliary cirrhosis in female C57BL/6 mice because of poly I:C administration.

BACKGROUND: Primary biliary cirrhosis (PBC) is one of the organ-specific autoimmune diseases characterized by destruction of the biliary epithelial cells, cholestasis, liver cirrhosis, and liver failure. With the postulation that induction of the autoimmune process might induce PBC-like cholangitis, here we used polyinosinic polycytidylic acid (poly I:C), an inducer of type-1 interferon (IFN), to generate an autoimmune cholangitis animal model. METHODS: Female C57BL/6 mice were injected with 5 mg/kg of poly I:C twice a week for 28 consecutive weeks. Liver specimens were collected to evaluate the degree of cell infiltration. Autoantibodies, including antimitochondrial antibody (AMA), were assayed by immunofluorescence, enzyme-linked immunosorbent assay (ELISA) and immunoblotting. IFN-alpha was estimated in the sera by an ELISA method. Poly I:C injection induced IFN-alpha. RESULTS: Mononuclear cells were detected at the portal areas 8 weeks after the start of poly I:C injection, which progressed up to 16 weeks. Autoantibodies, including AMA, were detected in the sera from all poly I:C-injected mice. CONCLUSIONS: In conclusion, we show an early development of a PBC-like cholangitis in a genetically susceptible mouse strain because of poly I:C administration. This model would be helpful to study PBC immunopathogenesis and to evaluate the effectiveness of newly developed therapeutic regimens for PBC.

Therapeutic efficacy of decreased nitrite production by bezafibrate in patients with primary biliary cirrhosis.

BACKGROUND: The therapeutic efficacy of bezafibrate, a hypolipidemic drug, has been shown in patients with primary biliary cirrhosis (PBC) in some pilot studies; however, little is known regarding the mechanism of action of bezafibrate in PBC. This study was conducted to evaluate the therapeutic efficacy, as well as to gain insight about the possible mechanism of action, of bezafibrate in PBC. METHODS: Sixteen patients with PBC were administered with bezafibrate (400 mg/day) either with (n = 10) or without ursodeoxycholic acid (UDCA; n = 6). The peripheral blood of these patients was collected before and at different times after therapy commencement, and antigen-presenting dendritic cells (DCs) were then cultured. The DCs were enriched and cultured with Staphylococcus aureus Cowan strain-1 for 48 h to evaluate their capacity to produce nitrite. RESULTS: One month after the start of bezafibrate therapy, the serum levels of alkaline phosphatase (P = 0.0005), gamma-glutamyl transpeptidase (P = 0.0006), total cholesterol (P = 0.0072), and immunoglobulin M (P = 0.0281) were decreased significantly compared to those before patients started bezafibrate therapy. The levels of nitrite produced by DCs decreased in all patients with PBC within 1 month of commencement of bezafibrate therapy. Moreover, decreased nitrite production by DCs was also seen when nitrite production was evaluated 1 year after the start of bezafibrate therapy. CONCLUSIONS: This study reconfirms the therapeutic efficacy of bezafibrate in patients with PBC, including those with UDCA-resistant PBC. Downregulation of nitrite production by DCs may have some relationship with the therapeutic efficacy of bezafibrate; however, further study will be needed to clarify whether or not the antiinflammatory activity of bezafibrate is mediated through nitrite production.

Soluble CD163 in patients with liver diseases: very high levels of soluble CD163 in patients with fulminant hepatic failure.

BACKGROUND: The levels of several cytokines and chemokines are elevated in various liver diseases, especially in fulminant hepatic failure (FHF). Activated macrophages may have a role in the production of these immune modulators. CD163 is a member of a scavenger receptor family and is expressed mainly on activated macrophages, and a soluble form of CD163 (sCD163) is released from activated macrophages. The aim of this study was to assess sCD163 levels in patients with FHF and to evaluate their clinical significance. METHODS: The levels of sCD163 in the sera were measured in 21 patients with FHF, 17 patients with acute hepatitis (AH), 22 patients with chronic hepatitis (CH), and 14 normal healthy controls (NC), by an enzyme-linked immunosorbent assay. The levels of sCD163 were observed serially in patients with FHF and AH. RESULTS: The levels of sCD163 in the sera from patients with FHF were significantly higher than those in patients with AH and CH and the NC group (P < 0.0001). There was a good correlation between serum levels of sCD163 and prothrombin time (r = -0.677; P < 0.0001). A kinetic study revealed that the levels of sCD163 decreased in patients with AH and in survivors of FHF, whereas the levels of sCD163 progressively increased in nonsurvivors of FHF. CONCLUSIONS: This study shows that the products of activated macrophages may be involved in the pathogenesis of FHF. This study also inspires optimism that sCD163 may possess prognostic importance in FHF.

On dendritic cell-based therapy for cancers.

Dendritic cells (DCs), the most prevalent antigen-presenting cell in vivo, had been widely characterized in the last three decades. DCs are present in almost all tissues of the body and play cardinal roles in recognition of microbial agents, autoantigens, allergens and alloantigen. DCs process the microbial agents or their antigens and migrate to lymphoid tissues to present the antigenic peptide to lymphocytes. This leads to activation of antigen-specific lymphocytes. Initially, it was assumed that DCs are principally involved in the induction and maintenance of adaptive immune responses, but now it is evident that DCs also have important roles in innate immunity. These features make DCs very good candidates for therapy against various pathological conditions including malignancies. Initially, DC-based therapy was used in animal models of cancers. Data from these studies inspired considerable optimism and DC-based therapies was started in human cancers 8 years ago. In general, DC-based therapy has been found to be safe in patients with cancers, although few controlled trials have been conducted in this regard. Because, the fundamentals principles of human cancers and animal models of cancers are different, the therapeutic efficacy of the ongoing regime of DC-based therapy in cancer patients is not satisfactory. In this review, we covered the various aspects that should be considered for developing better regime of DC-based therapy for human cancers.

Induction and maintenance of anti-HBs in immunosuppressed murine hepatitis B virus carriers by a novel vaccination approach: implications for use in hepatitis B virus-infected subjects with liver transplantation.

BACKGROUND: One of the major problems with orthotopic liver transplantation (OLT) in patients with endstage liver diseases due to hepatitis B virus (HBV) is to maintain sustained high levels of antibody to hepatitis B surface antigen (anti-HBs) to block reactivation of HBV infection and allograft rejection. The aim of this study was to induce anti-HBs by a unique vaccination protocol, using hepatitis B surface antigen (HBsAg)-pulsed dendritic cells (DCs) in immunosuppressed murine HBV carriers. METHODS: Immunosuppressed murine HBV carriers were produced by injecting FK-506 (2 mg/kg), intraperitoneally, daily for 15 days in HBV-transgenic mice (Tg) expressing HBV-related mRNAs and proteins. HBsAg-pulsed DCs were prepared by culturing murine spleen DCs with HBsAg (100 microg) for 24 h. HBsAg-pulsed DCs were injected twice, at an interval of 2 weeks, to immunosuppressed HBV-Tg and the levels of anti-HBs were measured periodically for 4 months. RESULTS: Injection with FK-506 resulted in the production of immunosuppressed HBV-Tg, as evident by their low production of cytokine mRNAs and proteins. Two injections of HBsAg-pulsed DCs from immunosuppressed HBV-Tg induced anti-HBs in all immunosuppressed HBV-Tg within 4-8 weeks after the second injection. More than 10 IU/l of anti-HBs was detected in the sera in all but one immunosuppressed HBV-Tg for more than 4 months, although all immunosuppressed HBV-Tg were continuously provided with FK-506 on a daily basis for the entire duration of the study. CONCLUSIONS: The capacity of HBsAg-pulsed DCs to induce anti-HBs in immunosuppressed HBV-Tg inspires optimism for the possible use of this therapeutic regimen for HBV-infected OLT patients.

Dendritic cell-based therapies in the bench and the bedsides.

Antigen-presenting dendritic cells (DCs) represent trace population of leukocytes that are widely distributed over the whole body. DCs are regarded as inducer of antigen-specific adaptive immune responses. However, various types of functions of DCs are now exposing. In the steady-state, DCs induce immunogenic tolerance to self antigens and harmless entities and thus maintain normal homeostasis. On the other hand, in presence of non-self and dangerous entities, DCs play a cardinal role in the induction of innate immunity by producing type-1 interferons. DCs are also essential for the development of antigen-specific B-lymphocytes and plasma cells. Infection, depletion and dysfunction of DCs have been reported from patients with chronic microbial infections. Impaired functions of DCs have also been shown from patients with autoimmune diseases and allergic diseases. Patients with cancers also have phenotypic and functional impairment of DCs. These observations inspired optimism of using DC-based therapy for treating different pathological conditions. DC-based therapies showed excellent therapeutic potential in animal model of human diseases. The efficacy of DC-based therapy has not been properly evaluated in patients with different diseases. However, some clinical trials indicate that administration of antigen-pulsed DCs might be safe and possibly effective. In this review, we would first provide a description about the nature and functions of DCs that have been taught from the laboratory benches. Next, we would discuss how the information taught in the laboratory benches has been applied in patient's bedsides.

Infection and dysfunction of circulating blood dendritic cells and their subsets in chronic hepatitis C virus infection.

BACKGROUND: To understand interactions between dendritic cells (DCs) and viruses, in vitro-cultured monocyte-derived DCs are usually used for functional analyses. However, several recent studies indicate that circulating blood DCs are different from monocyte-derived DCs, both phenotypically and functionally. Indeed, circulating DCs act as functional antigen-presenting cells in vivo. This study was conducted to evaluate the function of circulating blood DCs in patients with chronic hepatitis C and to examine whether circulating DCs from these patients were infected by hepatitis C virus (HCV). METHODS: The phenotypes and biological functions of circulating DCs from patients with chronic hepatitis C ( n = 27), patients with non-HCV chronic liver disease ( n = 7), and normal volunteers ( n = 13) were analyzed. The presence of the HCV genome sequence in circulating blood DCs and in subsets of circulating DCs (myeloid DCs and plasmacytoid DCs) in patients with chronic hepatitis C was assessed. RESULTS: The stimulatory capacity of circulating DCs was significantly reduced in patients with chronic hepatitis C compared to patients with non-HCV chronic liver diseases and normal controls ( P < 0.01). HCV RNA was identified in the overall population of circulating DCs, and in myeloid DCs and plasmacytoid DCs. Nucleotide sequences of the 5' non-coding region of HCV RNA showed marked differences between paired samples of circulating DCs and sera from the same patients. CONCLUSIONS: Our results indicate the dysfunction and infection of circulatory blood DCs in chronic HCV infection. This may compromise the capacity of patients with hepatitis C to induce an effective antiviral immune response.

Vaccine therapy for hepatitis B virus carrier.

Despite the presence of an effective prophylactic vaccine since 1982, more than 350 million people of the world are now chronically infected with hepatitis B virus (HBV). In one scenario, a considerable numbers of chronic HBV carrier would eventually develop serious complications like liver cirrhosis and hepatocellular carcinoma. In another, chronic HBV carriers would be permanent sources of HBV infection and transmit HBV to uninfected healthy individuals. Taken together, chronic HBV infection represents a major global public health problem, especially in the developing nations of the Asia and Africa, where most of the chronic HBV-carriers reside. Unfortunately, there is no good curative therapy approach for these patients. The prospect of treatment of chronic HBV infection by antiviral agents like type-1 interferons and lamivudine is not satisfactory due to their low efficacy, considerable side effects and high costs. Vaccine therapy, an immune therapy, has recently shown considerable optimism for treating patients with chronic HBV infection. In this review, we will first describe the pathogenesis of chronic HBV carrier state to provide scientific and ethical rationales of vaccine therapy in chronic HBV carriers. Next, we will summarize the information that has been compiled from ongoing clinical trials of vaccine therapy in chronic HBV carrier. Finally, we will discuss the mechanism of action of vaccine therapy in patients with chronic HBV infection and HBV transgenic mice, a murine model of chronic HBV carrier state. This information will be valuable for developing next generation therapeutic vaccines for the management of chronic HBV infection.

Inability of liver dendritic cells from mouse with experimental hepatitis to process and present specific antigens.

The functions of resident antigen-presenting cells (APC) may be compromised in inflammatory microenvironment of the host. However, little is known regarding the phenotype and function of the liver resident APC in this condition. This issue was addressed by evaluating the function of liver dendritic cells (DC) from mice with concanavalin-A-induced experimental hepatitis. In sharp contrast to normal mice, the expressions of MHC class II and CD86 antigens were not upregulated on liver DC from mice with hepatitis due to interactions with specific antigens like hepatitis B surface antigen and keyhole limpet hemocyanin. Accordingly, these DC were completely unable to induce proliferation of antigen-specific memory lymphocytes. Moreover, liver DC from mice with hepatitis produced significantly lower levels of interleukin-12 and interferon-gamma compared with those from control mice. The lack of antigen internalization capacity of liver DC from mice with hepatitis was evident from their low endocytosis capacity. These data indicate that impaired antigen capturing and T cell activating capacity of liver DC may contribute to low magnitude of antigen-specific immune responses in mice with experimental hepatitis.

Depletion and decreased function of antigen-presenting dendritic cells caused by lymphocytapheresis in ulcerative colitis.

PURPOSE: The therapeutic efficacy of lymphocytapheresis in autoimmune diseases is presumed to be caused by depletion of activated lymphocytes. However, nothing is known about the inducer of activated lymphocytes, the antigen-presenting dendritic cells, during lymphocytapheresis. BASIC PROCEDURES: Six sessions of lymphocytapheresis were done in five patients with ulcerative colitis. Dendritic cells were enriched from the buffy coat of depleted lymphocytes and also from the peripheral blood. The phenotype and function of dendritic cells were studied by dual-color flow cytometry and in allogenic mixed leukocyte reaction, respectively. The serum levels of inflammatory cytokines (interleukin-1alpha 6, 8, 10, and 12 and tumor necrosis factor-alpha and beta) were measured before and after lymphocytapheresis in all cases. MAIN FINDINGS: Lymphocytapheresis was safe and caused clinical, endoscopic or histologic improvements in all patients with ulcerative colitis. Many CD83-positive mature dendritic cells were found in the buffy coats after each session of lymphocytapheresis. The function of dendritic cells, the frequencies of CD83-positive dendritic cells and the levels of interleukin-6 and interleukin-8 were down regulated in all patients with ulcerative colitis after lymphocytapheresis compared with their levels before lymphocytapheresis. CONCLUSIONS: Depletion and down regulation of the function of dendritic cells and diminished levels of inflammatory cytokines caused by lymphocytapheresis may contribute to the therapeutic efficacy of lymphocytapheresis.

Antigen-presenting dendritic cells in ulcerative colitis.

BACKGROUND: Antigen-presenting dendritic cells are the inducers and regulators of immune responses. Here, we have discussed the phenotype and function of dendritic cells in situ and their alteration during lymphocytapheresis in patients with ulcerative colitis. METHODS: Dendritic cells were enriched from the peripheral blood mononuclear cells by culturing with granulocyte-macrophage colony-stimulating factors and interleukin 4 for 8 days. The function of dendritic cells was evaluated in an allogenic mixed leukocyte reaction. Flow cytometry was employed to study the phenotype of dendritic cells. Lymphocytapheresis was done by a continuous flow centrifugation technique using a CS-3000 separator. Immunohistochemical methodology was employed to detect dendritic cells at the colonic mucosa. RESULTS: Peripheral blood dendritic cells had increased functional capacity, and these cells were matured and activated compared to dendritic cells from normal controls. CD83-positive activated and mature dendritic cells were found at the colonic mucosa from patients with ulcerative colitis. Lymphocytapheresis induced decreased function of peripheral blood dendritic cells in patients with ulcerative colitis. Also, the levels of inflammatory cytokines were reduced by lymphocytapheresis. CONCLUSIONS: Increased function of dendritic cells may be related to the inflammatory mucosal milieu found in patients with ulcerative colitis. Depletion of dendritic cells during lymphocytapheresis may downregulate the exacerbated immune response in patients with ulcerative colitis.

Loss of immunogenecity of liver dendritic cells from mouse with chronic hepatitis.

Antigen presenting cells, especially the antigen presenting dendritic cells (DC) in the tissue, regulate the magnitude of antigen-specific immune response. A role of impaired and narrowly focused specific immune response has been implicated in the pathogenesis of chronic hepatitis due to hepatitis B virus and hepatitis C virus. In order to clarify this role, we studied liver DC from interferon gamma (IFN-gamma) transgenic mouse (TgM), an animal model of chronic hepatitis. These mice had high serum levels of alanine transaminase and histological evidence of chronic hepatitis. Transgene negative offspring (littermate control) with normal serum transaminase levels and without any evidence of hepatitis were used as controls. The stimulatory capacity of the liver DC from IFN-gamma TgM in allogenic mixed leukocyte reaction was significantly lower than that of the liver DC from control mouse. The endocytosis capacity was significantly lower in liver DC from IFN-gamma TgM than in that from the control mouse. Most importantly, liver DC from IFN-gamma TgM were unable to induce antigen-specific proliferation. The impaired function of liver DC from these mice may be attributable to increased production or induction of suppressor cytokines such as interleukin-10 and nitric oxide. Defective capacity of liver DC from mouse with chronic hepatitis (IFN-gamma TgM) may be related to impaired magnitude of specific immune response in the liver.

Clinical characteristics of autoimmune hepatitis with histological features of acute hepatitis.

The number of patients with autoimmune hepatitis with histological features of acute hepatitis (AIH-AH) has been increasing recently. Here, the clinical features of patients with AIH-AH have been compared with those of patients with AIH with histological findings of chronic hepatitis (AIH-CH) and liver cirrhosis (AIH-LC). The levels of total serum bilirubin (P<0.05) and serum transaminases (P<0.05) were significantly higher in patients with AIH-AH than in patients with AIH-CH and AIH-LC. However, the serum levels of gamma-globulin (P<0.05) and immunoglobulin G (P<0.05) were significantly lower in AIH-AH than in patients with AIH-CH and AIH-LC. The aggregate score according to the criteria of the International Autoimmune Hepatitis Group in 1999 was also significantly lower in AIH-AH patients than in patients with AIH-CH and AIH-LC (P<0.05). Eleven patients with AIH-AH were treated with corticosteroids, however, the clinical response was insignificant in three patients. In summary, it is difficult to diagnose of patients with AIH-AH using the criteria of the International AIH scoring system. We wish that this scoring system would be modified in the near future.