Peripheral blood dendritic cells are phenotypically and functionally intact in chronic hepatitis B virus (HBV) infection.

Persistence of hepatitis B virus (HBV) infection is associated with reduced anti-viral T cell responses. Impaired dendritic cell (DC) function was suggested as the cause of reduced T cell stimulation in chronic HBV carriers. Thus, we compared myeloid (mDC) and plasmacytoid DC (pDC) from chronic HBV carriers and controls. Frequency and phenotype of isolated DC were analysed by fluorescence activated cell sorter staining, DC function by mixed lymphocyte reaction, cytokine bead array, intracellular cytokine staining, enzyme-linked immunosorbent assay and enzyme-linked immunospot. Expression of HBV DNA and mRNA was studied by polymerase chain reaction (PCR). Circulating total DC, mDC or pDC were not reduced in chronic HBV carriers. Isolated mDC and pDC from chronic HBV carriers exhibited similar expression of co-stimulatory molecules and alloreactive T helper cell stimulation as control DC, whether tested directly ex vivo or after in vitro maturation. Secretion of pro- and anti-inflammatory cytokines by CD40 or Toll-like receptor ligand-stimulated patient DC was intact, as was human leucocyte antigen A2-restricted HBV-specific cytotoxic lymphocyte stimulation. Although both DC populations contained viral DNA, viral mRNA was undetectable by reverse transcription-PCR, arguing against viral replication in DC. We found no quantitative, phenotypic or functional impairment of mDC or pDC in chronic hepatitis B, whether studied ex vivo or after in vitro maturation.

Hepatitis B surface antigen presentation and HLA-DRB1*- lessons from twins and peptide binding studies.

The aim of this study was to investigate the underlying mechanisms of the genetic association between certain HLA-DRB1* alleles and the immune response to HBsAg vaccination. Therefore, HBsAg peptide binding to HLA-DR molecules was measured in vitro by peptide binding ELISAs. Additionally, HBsAg-specific T cell reaction and cytokine profile of immune response were analysed ex vivo in ELISPOT assays and DR-restriction of T-cell proliferative responses was investigated with HBsAg specific T cell clones. In addition, we compared HBsAg specific T cell responses of 24 monozygotic and 3 dizygotic twin pairs after HBsAg vaccination. Our results showed that the peptide binding assays did not reflect antigen presentation in vivo. DR alleles associated with vaccination failure like DRB1*0301 and 0701 efficiently presented HBsAg peptides. In 11 of 24 investigated monozygotic twin pairs we observed pronounced differences in the recognition of HBsAg peptides. This study indicates that HLA-DR associations with HBsAg vaccination response are not caused by differences in peptide binding or by a shift in the Th1/Th2 profile. Our findings strongly argue for differences in the T cell recognition of peptide/MHC complexes as the critical event in T cell responsiveness to HBsAg.

Reduced virus specific T helper cell induction by autologous dendritic cells in patients with chronic hepatitis B - restoration by exogenous interleukin-12.

Insufficient stimulatory capacities of autologous dendritic cells (DC) may contribute in part to impaired T cell stimulation and therefore viral persistence in patients with chronic hepatitis B virus (HBV) infection. In order to characterize the antigen presenting functions of DC from chronic HBV carriers and controls antigen specific T cell responses were analysed. CD34+ peripheral blood progenitor cells were differentiated to immature DC in the presence of GM-CSF, IL-6/IL-6R fusion protein and stem cell factor. Proliferative CD4+ T cell responses and specific cytokine release were analysed in co-cultures of DC pulsed with HBV surface and core antigens or tetanus toxoid and autologous CD4+ T cells. Cultured under identical conditions DC from chronic HBV carriers, individuals with acute resolved hepatitis B and healthy controls expressed similar phenotypical markers but chronic HBV carriers showed less frequent and weaker HBV antigen specific proliferative T helper cell responses and secreted less interferon-gamma while responses to the tetanus toxoid control antigen was not affected. Preincubation with recombinant IL-12 enhanced the HBV specific immune reactivities in chronic HBV patients and controls. In conclusion, the weak antiviral immune responses observed in chronic hepatitis B may result in part from insufficient T cell stimulating capacities of DC. Immunostimulation by IL-12 restored the HBV antigen specific T cell responses and could have some therapeutical benefit to overcome viral persistence.

Induction of strong hepatitis B virus (HBV) specific T helper cell and cytotoxic T lymphocyte responses by therapeutic vaccination in the trimera mouse model of chronic HBV infection.

Humanized BALB/c mice (termed trimera mice) conditioned by lethal total body irradiation and bone marrow transplantation from SCID mice have been described to support rapid engraftment of human peripheral blood mononuclear cells (PBMC) and the induction of strong B and T cell responses after immunization in vivo. Moreover, these mice can be infected with the hepatitis B and C viruses (HBV, HCV). The current study employed this model to study therapeutic vaccination approaches against the HBV. Thus, strong primary Th cell responses against the HBV core (HBc) and the Borrelia burgdorferi control antigen were induced by transfer of antigen-loaded dendritic cells together with autologous PBMC from HBV-naive donors as well as by vaccination with high doses of antigen or a DNA plasmid encoding for HBcAg. Moreover, primary peptide-specific CTL responses against the immunodominant epitope HBc(18 - 27) were induced by HBc particle or DNA vaccination of chimera engrafted with HBV-naive PBMC. Finally, strong HBc-specific Th cell and antibody responses were induced by HBc or DNA vaccination of mice reconstituted with PBMC from a chronic HBV patient. Thus, since HBc represents the immunodominant antigen in self-limited HBV infection, HBc particles or DNA vectors are good candidates for therapeutic vaccination, that will be further studied in our model and clinical studies.

In vivo modulation of the allogeneic immune response by human fetal kidneys: the role of cytokines, chemokines, and cytolytic effector molecules.

BACKGROUND: We have recently demonstrated that human fetal renal tissue, implanted under the kidney capsule of severe immunodeficient rats, escapes early destruction by intraperitoneal infusion of allogeneic human peripheral blood mononuclear cells, compared with the rapid rejection of implants of human adult kidney tissue. Variable amounts of human mononuclear infiltrates were seen in the transplanted fetal kidney, however, prolonged survival of the fetal tissue (maintenance of graft architecture and significant growth) was independent of the cellular infiltrate. METHODS: We have used this experimental model to sequentially analyze transcript levels of interferon-gamma and interleukin (IL)-2 (T helper 1 cytokines), IL-4 and IL-10 (T helper 2 cytokines), RANTES, MIP1beta (beta chemokines) and their receptor CCR5, and Fas ligand (cytolytic effector molecule). Analysis was performed by reverse transcriptase-polymerase chain reaction, in both fetal and adult kidney grafts, after infusion of allogeneic human peripheral blood mononuclear cells. RESULTS: Transcript levels of interferon-gamma and IL-2 in the fetal grafts were markedly reduced throughout follow-up, compared with those observed in the adult implants. Peak levels of these cytokines appeared late in the rejection process. Concomitant with these findings, IL-4 mRNA was up-regulated during the early phase, whereas IL-10 mRNA persisted throughout the rejection process, indicating that a T helper 2 bias occurred in the fetal grafts. In addition, RANTES (after an early peak), MIP1beta, CCR5, and Fas ligand mRNA levels were suppressed in the fetal grafts compared with those in the adult grafts. CONCLUSIONS: These findings indicate that the immune response of kidney rejection is dependent on whether the target organ is of fetal or adult origin, and suggest that an allogeneic immune system mounts a T helper 2-biased response when the target organ is of fetal origin.

Reduced hepatitis B virus surface antigen-specific Th1 helper cell frequency of chronic HBV carriers is associated with a failure to produce antigen-specific antibodies in the trimera mouse.

In chronic hepatitis B virus (HBV) infection weak antiviral immune responses are associated with viral persistence. We studied possible immune deficits underlying the lack of serum antibodies of such patients against the HBV surface antigen (HBsAg) in a novel human/mouse chimeric model. A hepatitis B surface antigen (HBs) vaccination of Balb/c mice engrafted with peripheral blood mononuclear cells (PBMC) of naturally HBV-immunized donors induced high frequencies of human HBsAg-specific B and T helper 1 (Th1) cells. These responses were associated with high serum anti-HBs antibody levels of the subclasses immunoglobulin G1 (IgG1) and IgG2 that are driven by interleukin-2 (IL-2) and interferon-gamma (IFN-gamma). In contrast, PBMC of chronic HBV carriers transplanted into the chimera failed to produce anti-HBs antibodies after vaccination with HBsAg and exhibited a deficit of antigen-specific Th1 cells. A possible influence of HBsAg or viremia was excluded by the lack of viral replication in such chimera. The observed T-cell defect was specific for HBsAg, as the B- and T-cell responses to tetanus toxoid (TT) were fully retained. Thus, our study shows that viral persistence in chronic HBV carriers is associated with an HBsAg-specific Th1 cell defect, which likely is responsible for the insufficient neutralizing anti-HBs-antibody response and is not reversed by HBs vaccination. Alternative approaches to induce HBs-specific Th1 cell responses might represent a future therapeutic option.

Cellular and humoral immune responses induced by intradermal or intramuscular vaccination with the major hepatitis B surface antigen.

The vaccination route may influence the success of immunization against pathogens. The conventional intramuscular (i.m.) application of a vaccine containing the hepatitis B virus (HBV) surface antigen (HBsAg) led to protective anti-HBs antibody levels in the majority of vaccine recipients. In this study, we vaccinated healthy volunteers and a group of i.m. vaccine nonresponders via the intradermal (i.d.) route and analyzed the HBV-specific B-cell response as well as class-II- and class-I-restricted T-cell responses by (3)H-thymidine uptake, enzyme-linked immunosorbent assay (ELISA) and enzyme-linked immunospot assay (ELISPOT). The results were then compared with i.m. vaccinated controls. I.d. vaccinations were well tolerated and induced neutralizing anti-HBs antibodies in all naive vaccine recipients and, importantly, all but one former i.m. nonresponder developed protective anti-HBs serum antibody levels after 2 or 3 i.d. immunizations. On the cellular level, i.d. vaccine recipients showed significantly higher anti-HBs producing B-cell frequencies and more vigorous class-II-restricted T-helper (Th) cell responses than i.m. controls. However, although the HBsAg-specific T cells were characterized by their cytokine release as Th1-like cells in both groups, human leukocyte antigen (HLA)-A2+ individuals who received the soluble HBsAg via the i.d. route developed higher peptide-specific cytotoxic CD8+ T cell precursor (CTLp) frequencies. In conclusion, i.d. HBsAg vaccination is more effective even in former i.m. vaccine nonresponders with respect to antibody induction and specific B- and T-cell responses. The induction of virus-specific CTLp may provide the rationale to study the i.d. HBsAg vaccine in the treatment of chronic hepatitis B.

Acute cellular rejection of human renal tissue by adoptive transfer of allogeneic human peripheral blood mononuclear cells into chimeric rats: sequential gene expression of cytokines, chemokines and cytolytic effector molecules, and their regulation by CTLA-4-Ig.

T(h)1- and T(h)2-related cytokines (IFN-gamma, IL-2, IL-4, IL-10), beta-chemokines (RANTES, macrophage inflammatory protein-1beta) and their receptor [chemotatic cytokine receptor (CCR) 5], and the cytolytic effector molecule [Fas ligand (FasL)] play an essential role in regulating and co-ordinating acute renal allograft rejection. A chimeric model of acute cellular rejection which involves subcapsular grafting of human renal tissue in the kidneys of immunodeficient rats and subsequent i.p. infusion of allogeneic human peripheral blood mononuclear cells (PBMC) was used to study cellular infiltration patterns and sequential intragraft gene expression of these key inflammatory mediators. We found that while all molecules are expressed within the human renal implant at specific time points following infusion of allogeneic human PBMC, peak mRNA expression of IFN-gamma, IL-2, RANTES and CCR5 is associated with a phase of human mononuclear infiltration and accumulation, prior to graft destruction (induction phase). A short burst of FasL gene expression is found at the end of induction and at the onset of graft deterioration. IL-4 mRNA, which is hardly detectable, and IL-10 mRNA, which appears early and persists throughout follow-up at high levels, both peak after the induction phase with the advent of graft destruction. Furthermore, treatment with CTLA-4-Ig, which hardly affects migration of human effector cells into graft tissue, is associated with a temporary reduction in gene transcript levels for all inflammatory mediators, especially IL-2 and IL-4, reduced apoptosis in the graft and amelioration of tissue injury. Thus, development of acute cellular rejection in our chimeric model involves a co-ordinated pattern of gene expression, in which CTLA-4-Ig promotes its effects by transient inactivation of infiltrating human cells.

Antigen-specific B and T cells in human/mouse radiation chimera following immunization in vivo.

Adoptive transfer of human peripheral blood mononuclear cells (PBMC) into mice with severe combined immunodeficiency (SCID) or into lethally irradiated BALB/c mice radioprotected with SCID bone marrow, leads to marked engraftment of human T and B cells. In such chimeras, human serum antibody responses can be stimulated readily by vaccination with recall antigens, but the detection of antigen-specific functional T or B cells has been extremely difficult. In the present study, we were able to detect by Elispot analysis high frequencies of immunoglobulin G (IgG)-secreting B cells and mitogen-responsive interferon-gamma (IFN-gamma) or interleukin-4 (IL-4)-secreting T cells in peritoneum and spleen of human/BALB/c chimeric mice during the first 3 weeks after PBMC transfer. Moreover, specific memory responses were elicited by vaccination with tetanus toxoid (TT) or hepatitis B virus (HBV) surface (HBs) antigen of chimeric mice transplanted with PBMC derived from TT- or HBV-immune donors. Substantially higher TT-specific B-cell frequencies were found during the first 3 weeks after vaccination in mice challenged with the specific antigen compared to the levels found in control animals. High numbers of TT-specific IFN-gamma-secreting T cells persisted in the peritoneum of vaccinated, but not of unvaccinated, animals during the entire observation period, but only low numbers of specific IL-4-secreting T cells were found in vaccinated mice. Similar results were achieved following vaccination with HBs antigen of chimeric mice, transplanted with PBMC of HBV immunized donors. Thus, TT or HBsAg-specific antibody responses in our model correlate closely with the existence of specific IFN-gamma-secreting T helper 1/0 cells. Furthermore, these results show that adoptive transfer of human PBMC into lethally irradiated mice provides an efficient approach to generate specific B-cell fusion partners for the production of human monoclonal antibodies and specific T-cell lines for adoptive cell therapy of malignant or infectious diseases.

Kinetics of hepatitis B surface antigen-specific immune responses in acute and chronic hepatitis B or after HBs vaccination: stimulation of the in vitro antibody response by interferon gamma.

Because cellular and humoral immune responses against the hepatitis B virus (HBV) surface antigen (HBs) might be crucial to overcome HBV infection, HBs-specific B- and T-cell responses of HBV patients and HBs vaccine recipients were analyzed quantitatively and functionally. In patients with acute hepatitis B (AHB), transient high anti-HBs-secreting B-cell frequencies were observed early after clinical onset, whereas 1 patient who probably developed chronic infection and chronic HBV carriers had absent or weak B- and T-cell responses. In HBs vaccine recipients, maximal HBs-specific B- and T-cell responses were detected after the first injection that decreased gradually before anti-HBs antibodies appeared in serum. Years after vaccination, anti-HBs-secreting B cells were enriched in the bone marrow. After in vitro stimulation with HBsAg, peripheral blood mononuclear cells (PBMC) of only 1 of 5 acute and 1 of 6 chronic HBV patients, but of all 6 vaccine recipients, secreted varying amounts of interferon gamma (IFN-gamma), but no interleukin-4 (IL-4) or IL-5. Furthermore, the addition of IFN-gamma, but not of IL-2, -4, -12, or IFN-alpha, resulted in strong increases of anti-HBs-secreting B cells in vaccine recipients and chronic carriers. In conclusion, circulating anti-HBs-secreting B cells were significantly higher in early acute hepatitis B or early after HBs vaccination than in chronic hepatitis B and decreased in the follow-up as a result of compartmentalization to lymphoid tissues. Release of IFN-gamma by antigen-stimulated T cells might be critical for anti-HBs formation.

Autoreactive CD4+ LKM-specific and anticlonotypic T-cell responses in LKM-1 antibody-positive autoimmune hepatitis.

Peripheral blood mononuclear cells (PBMC) of patients with autoimmune hepatitis (AIH) and controls were studied for their proliferative response to six overlapping synthetic peptides covering the 33-amino acid immunodominant region of cytochrome P450IID6, the main target antigen of LKM-1 antibody-positive type II AIH. PBMC from 8 of 8 type II AIH patients (100%), 6 of 12 LKM-1 antibody-negative type I AIH patients (50%), but only 4 of 31 patients with chronic hepatitis C (12.9%) reacted with a 23-amino acid LKM peptide and mainly with a shorter 18-amino acid LKM peptide. Follow-up showed that LKM-specific T-cell responses decreased after immunosuppression had started. Fine specificity, HLA restriction, and cytokine release of LKM-specific T cells were analyzed with 16 CD4+ peptide-specific T-cell lines and 21 CD4+ T-cell clones isolated and expanded from blood and liver tissue of six AIH patients. Activated LKM-specific T cells released interferon gamma (IFN-gamma) but no or little interleukin-4. In three AIH patients, PBMC showed specific recognition of autologous LKM-specific T cells, suggesting the presence of a regulatory T-cell network. These T cells also showed the CD4+ phenotype and secreted large amounts of IFN-gamma. Furthermore, it was assessed that the regulatory T-cell response is clonotypic. To conclude, we describe a major T-cell epitope in AIH that was recognized by Th1 helper cells isolated from blood and liver tissue. This autoreactive T-cell response correlated widely with disease activity and LKM-1 antibody status and seemed to be regulated by anticlonotypic T cells.

Regulation of the neutralizing anti-hepatitis B surface (HBs) antibody response in vitro in HBs vaccine recipients and patients with acute or chronic hepatitis B virus (HBV) infection.

Antibodies directed to the HBs antigen indicate viral clearance and the development of life-long immunity in patients that recovered from HBV infection. In HBs antigen vaccine recipients anti-HBs antibodies provide protective immunity. However, little is known about the regulation of this HBs-specific antibody response. The existence of anti-HBs-secreting B cells was demonstrated using the highly sensitive ELISPOT technique compared with conventional ELISA in serum and cell culture supernatants. In the peripheral blood of patients with acute self-limited hepatitis B, HBs-specific B cells were demonstrated with a high frequency despite undetectable anti-HBs serum antibodies. HBV-immunized patients that had recovered from infection and vaccine recipients had significantly lower frequencies, whereas chronic HBV carriers and negative controls showed no anti-HBs-secreting B cells. Coculture experiments of isolated B and T cells revealed that the anti-HBs antibody response was restricted to the presence of T helper cells, but not to identical HLA class II molecules. Allogeneic T cells derived from vaccine recipients or chronic HBV carriers stimulated the HBs-specific B cell response in HBs vaccine recipients. Otherwise, isolated T helper cells could never provide sufficient help to induce the HBs-specific B cell responses in chronic HBV carriers. Furthermore, peripheral blood mononuclear cells (PBMC) of six out of 10 vaccine recipients, one out of five HBV-immunized patients, but of no chronic HBV carrier showed a proliferative response to different HBs antigen preparations. This study demonstrated a high frequency of circulating anti-HBs-producing B cells in the early phase of acute HBV infection, but a lower frequency of HBs-specific B cells years after resolution of HBV infection. In chronic HBV carriers. However, deficient HBs-specific T and B cell responses were observed.

Hepatic manifestation of hemolytic uremic syndrome in an allogeneic bone marrow transplant recipient.

A 33-year-old woman presented 42 days after allogeneic bone marrow transplantation for acute monocytic leukemia (AML, FAB M5) with persistent thrombocytopenia, acute renal failure and Coombs negative hemolytic anemia. In the absence of the disseminated intravascular coagulation the diagnosis of hemolytic uremic syndrome due to immunosuppression with cyclosporin A was supposed. Because cessation of cyclosporin A and therapeutic infusions of fresh frozen plasma had failed, plasmaseparation therapy was started on day 79 after bone marrow transplantation. While hemolytic anemia improved during ongoing plasmaseparations the patient developed cholestatic liver failure due to hepatic manifestation of HUS. The histological lesions of liver involvement in thrombotic microangiopathies are discussed and a review of the literature is presented.

Detection of hepatitis C virus replication in ovarian metastases of a patient with hepatocellular carcinoma.

Hepatocellular carcinoma is one of the most common human cancers with an annual incidence of about 1,000,000 cases worldwide. Although hepatocellular carcinoma is predominant in hepatitis B virus endemic areas, it has also become a major problem in Europe, Japan and North America in close association with the increasing incidence of hepatitis C virus infection. The pathogenetic role of hepatitis C virus infection in the development of HBsAg-negative hepatocellular carcinoma needs to be clarified. In this paper the case of a 66-year-old HBsAg-negative and anti-HCV positive female who developed hepatocellular carcinoma in a cirrhotic liver is reported. After 1 year of follow up, urgent laparotomy had to be performed due to highly differentiated ovarian metastases of the hepatocellular carcinoma. Plus- and minus-stranded HCV-RNA was detected by reverse transcription and "nested" polymerase chain reaction in both the patient's serum and in the metastatic ovarian tissue.

Interstitial alveolitis as early manifestation of anti-Jo-1 positive polymyositis.

Polymyositis (PM), dermatomyositis (DM) and inclusion-body myositis belong to a heterogenous group of inflammatory myopathies. Pulmonary manifestations occur in a minority of PM patients due to infiltration of diaphragmatic and thoracic muscles or more rarely due to interstitial lung disease. Here, we report on the case of a 67-year-old patient who developed an interstitial idiopathic alveolitis as an early and rare manifestation of anti-Jo-1-positive polymyositis. Clinical and pathogenetical features of the PM associated interstitial alveolitis are discussed.