The expression of IL-2, IL-4 and interferon-gamma (IFN-gamma) mRNA using liver biopsies at different phases of acute exacerbation of chronic hepatitis B

Immunopathogenesis of Acute Flare of Chronic Hepatitis B: With Emphasis on the Role of Cytokines and Chemokines

Acute flares (AFs) of chronic hepatitis B usually occur during the immune-active stage (both immune clearance phase and immune reactivation phase), as the host immune system tries to control the virus. Successful host immune control over viral replication is usually presented as hepatitis B surface antigen seroclearance; however, 20–30% individuals with chronic hepatitis B may encounter repeated AFs with accumulative liver injuries, finally leading to the development of cirrhosis and hepatocellular carcinoma. AF can also develop in other clinical situations such as organ transplantation, cancer chemotherapy, and under treatment for chronic hepatitis B or treatment for chronic hepatitis C in patients with co-infected hepatitis B/hepatitis C. Understanding the natural history and immunopathogenesis of AF would help develop effective strategies to eradicate the virus and improve the clinical outcomes of patients with chronic hepatitis B. In this review article, the immunopathogenesis of AF, and the involvement of innate and adaptive immune responses on the development of hepatitis B flare will be briefly reviewed, with the emphasis on the role of cytokines and chemokines.

INASL Guidelines on Management of Hepatitis B Virus Infection in Patients receiving Chemotherapy, Biologicals, Immunosupressants, or Corticosteroids

Hepatitis B Virus (HBV) reactivation in patients receiving chemotherapy, biologicals, immunosupressants, or corticosteroids is emerging to be an important cause of morbidity and mortality in patients with current or prior exposure to HBV infection. These patients suffer a dual onslaught of illness: one from the primary disease for which they are receiving the culprit drug that led to HBV reactivation, and the other from HBV reactivation itself. The HBV reactivation not only leads to a compromised liver function, which may culminate into hepatic failure; it also adversely impacts the treatment outcome of the primary illness. Hence, identification of patients at risk of reactivation before starting these drugs, and starting treatment aimed at prevention of HBV reactivation is the best strategy of managing these patients. There are no Indian guidelines on management of HBV infection in patients receiving chemotherapy, biologicals, immunosupressants, or corticosteroids for the treatment of rheumatologic conditions, malignancies, inflammatory bowel disease, dermatologic conditions, or solid-organ or bone marrow transplantation. The Indian National Association for Study of the Liver (INASL) had set up a taskforce on HBV in 2016, with a mandate to develop consensus guidelines for management of various aspects of HBV infection, relevant to India. In 2017 the taskforce had published the first INASL guidelines on management of HBV infection in India. In the present guidelines, which are in continuation with the previous guidelines, the issues on management of HBV infection in patients receiving chemotherapy, biologicals, immunosupressants, or corticosteroids are addressed.

Chronic Hepatitis B with Spontaneous Severe Acute Exacerbation

Chronic hepatitis B virus (HBV) infection is a major global health problem with an estimated 400 million HBV carriers worldwide. In the natural history of chronic hepatitis B (CHB), spontaneous acute exacerbation (AE) is not uncommon, with a cumulative incidence of 10%–30% every year. While exacerbations can be mild, some patients may develop hepatic decompensation and even die. The underlying pathogenesis is possibly related to the activation of cytotoxic T lymphocyte-mediated immune response against HBV. An upsurge of serum HBV DNA usually precedes the rise of alanine aminotransferase (ALT) and bilirubin. Whether antiviral treatment can benefit CHB with severe AE remains controversial, but early nucleos(t)ide analogues treatment seemed to be associated with an improved outcome. There has been no randomized study that compared the effects of different nucleos(t)ide analogues (NA) in the setting of CHB with severe AE. However, potent NAs with good resistance profiles are recommended. In this review, we summarized current knowledge regarding the natural history, pathogenetic mechanisms, and therapeutic options of CHB with severe AE.

Hepatitis B flares in chronic hepatitis B: pathogenesis, natural course, and management

Hepatitis B flare, defined as an event with abrupt rise of alanine aminotransferase (ALT) levels to >5 times the upper limit of normal during chronic hepatitis B virus (HBV) infection, is considered to be the result of a human leukocyte antigen-I restricted, cytotoxic T lymphocyte mediated immune response against HBV and its downstream mechanisms. It may occur spontaneously, during or after antiviral therapy and in the setting of immunosuppression and/or chemotherapy. The clinical spectrum of hepatitis B flares varies from asymptomatic to symptomatic and typical overt acute hepatitis, even with hepatic decompensation or failure. Flares may also occur in viraemic patients with cirrhosis with higher incidence of decompensation/mortality, hence requiring immediate antiviral therapy. An upsurge of serum HBV DNA and hepatitis B surface antigen levels usually precedes the abrupt rise of ALT levels. Rising or stable and high HBV DNA during flares represent ineffective immune clearance and further hepatocytolysis, even hepatic decompensation, may occur. Such patients require immediate antiviral therapy. In contrast, bridging hepatic necrosis and/or alpha-fetoprotein levels >100 ng/ml or decreasing HBV DNA during flares represent a more effective immune clearance and frequently leads to seroclearance of HBV DNA and/or hepatitis B e antigen with remission. If patients are non-cirrhotic and there is no concern of developing decompensation, patients may be observed for 3-6 months before deciding on the need of antiviral therapy. Severe and repeated flares are prone to develop into decompensation or lead to the development of cirrhosis, thus a timely treatment to prevent the hepatitis B flare is better than to cope with the flare. Screening, monitoring and prophylactic or pre-emptive antiviral therapy is mandatory for patients who are going to receive immunosuppressants or chemotherapy.

Research advances in the imbalance of helper T lymphocyte subpopulations and cytokine network in patients with chronic hepatitis B

Helper T (Th) lymphocytes, important immune regulating cells of organism, could be divided into four functional subsets, Th0, Th1, Th2, Th3, on the basis of the immunoregulatory cytokines that these clones produced. Most of the current work in this field is exploratory and focuses on Th1 and Th2 subsets. Th1 cells secrete interferon-γ (IFN-γ), interkeukin-2 (IL-2) and tumor necrosis factor-β and are principally involved in cell-mediated immunity. They play an important role in the protection against intracellular pathogens, including a variety of viruses. Th2 cells secret interleukin-4 (IL-4), IL-5, IL-6 and IL-10 and regulate the humoral immune response. Th0 cells are naive Th cells, secreting Th1/Th2 phenotype cytokines at low levels. However, Th3 cells, which secrete active transforming growth factor-β, exert a negative immunoregulatory action on the immune response. The cross-regulatory properties of Th1 and Th2 subset cells and relevant cytokines network are very important to maintain normal immunity of organisms. HBV can destroy the balance of Th lymphocytes and cytokines network. The imbalance of pro-inflammatory Th1 and anti-inflammatory Th2 cytokine production play an important role in the immunopathogenesis of hepatitis B virus infection and alter chronic liver disease development, progression and outcome.

PD-L1 is induced in hepatocytes by viral infection and by interferon-alpha and -gamma and mediates T cell apoptosis

BACKGROUND/AIMS

B7-H1 (PD-L1) is a B7-family member that binds to programmed death-1 (PD-1). Recently, deficiency of PD-L1 has been demonstrated to result in accelerated hepatocyte damage in experimental autoimmune hepatitis, and PD-L1 was suggested to play a critical role in regulating T cell homeostasis. Absence of PD-1 enhanced proliferation of T cells in adenovirus-infected livers and resulted in a rapid clearance of the virus. Here, we aimed to get more insight into hepatic PD-L1 expression, regulation and function.

METHODS

PD-L1 expression was analyzed by quantitative PCR and FACS-analysis in primary human liver cells and hepatoma cells. Furthermore, coculture experiments with primary human T cells or Jurkat T cells were established.

RESULTS

In addition to nonparenchymal liver cells, also hepatocytes constitutively expressed low levels of PD-L1. PD-L1 expression in hepatocytes was strongly enhanced by activated T cells and viral infection, and markedly augmented by further stimulation with type I or type II interferons. Moreover, PD-L1 expression on hepatocytes induced apoptosis in T cells.

CONCLUSIONS

Our results suggest a novel bidirectional interaction between hepatocytes and lymphocytes modulated by PD-L1 expression in hepatocytes, which may contribute to the unique immunological properties of the liver.

Growth factor attenuation of IFNgamma-mediated hepatocyte apoptosis requires p21waf-1

Interferon gamma (IFNgamma) is an important mediator of inflammatory liver damage as part of a complex cytokine network. In vitro, IFNgamma induces hepatocyte apoptosis. We hypothesized that the hepatocyte response to IFN signalling is context-dependent, and that specific growth factors, via phosphatidylinositol 3 kinase (PI(3)K) and protein kinase B/Akt signalling pathways, confer a cytoprotective effect. We established an in vitro model of IFNgamma-mediated primary hepatocyte injury. We show that epidermal growth factor (EGF) and hepatocyte growth factor (HGF) attenuate the IFNgamma-induced hepatocyte apoptosis. IRF-1, but not p53, is required for IFNgamma-mediated apoptosis. The loss of p21(waf-1) not only sensitizes the hepatocyte to IFNgamma-mediated injury but is required for survival factor mediated cytoprotection. We show that the PI(3)K inhibitor, LY294002, partially inhibits the apoptotic response of the hepatocyte to IFNgamma. In summary, we present evidence that a component of pro-apoptotic IFNgamma signalling in the primary hepatocyte occurs via the PI(3)K pathway. We show that the hepatocyte response to IFNgamma is modulated by external survival factors and that this survival signalling requires p21(waf-1).

Impaired Kupffer cells in highly susceptible mice infected with Trypanosoma congolense

In highly susceptible BALB/c mice infected with Trypanosoma congolense, the total number of Kupffer cells in the liver remains constant; however, their mean size increases fivefold towards the terminal stage. About 25% of Kupffer cells undergo apoptosis. We suggest that development of an impairment of the macrophage system might be a major mechanism for inefficient elimination of trypanosomes.

Fluctuation of the cytokine expression in the liver during the chronic woodchuck hepatitis virus (WHV) infection is not related to viral load

The woodchuck together with the woodchuck hepatitis virus (WHV) is an excellent model to study the pathogenesis of hepadnaviral infections. Chronic WHV infection causes severe liver disease and hepatocellular carcinoma in woodchucks. The mechanism of viral clearance is not fully understood, interferons seem to play a major role in down-regulating viral replication prior to elimination of infected hepatocytes. We investigated on the pattern of cytokine and T-cell-marker expression in livers of woodchucks chronically infected with WHV. RNase-protection-assay (RPA) was used to determine mRNA of woodchuck specific genes (TNF-alpha, IFN-gamma, IL-15, CD3, CD4, CD8). Serial liver biopsies were performed daily or weekly in eight chronic WHV-carrier woodchucks. Cytokine/T-cell-marker expression differed significantly between the time points up to +/-50% within each woodchuck. The different expression patterns of cytokines or T-cell-markers did not correlate to the (weak) fluctuations in the viremia but may explain the observed fluctuations in the WHV/HBV-load in chronically infected individuals. Furthermore, we observed associations between cytokine and T-cell-marker expression. The marginal fluctuations in viremia during the chronic infection may indicate, that, once the chronic hepadnaviral infection is established, cytokines/interferons expressed endogenously (i.e. not vector-borne or injected) play only a minor role.

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Hepatitis B core antigen is a potent inductor of interleukin-18 in peripheral blood mononuclear cells of healthy controls and patients with hepatitis B infection

Clearance of hepatitis B virus infection (HBV) infection implies a polyclonal vigorous T-helper 1 (Th1) and cytotoxic T-lymphocyte (CTL) response. Interleukin-18 (IL-18), a monokine that shares functional abilities with IL-12, is a potent inductor of interferon-gamma (IFN-gamma) by Th1 and natural killer (NK) cells. However, the role and regulation in HBV infection of IFN-gamma have not been defined. This study therefore sought to determine hepatitis B core antigen (HBcAg)-mediated regulation of IL-18 production in peripheral blood mononuclear cells (PBMCs) from healthy controls (HC) and patients with chronic hepatitis B (CHB) or acute hepatitis B (AHB); 31 HC, 27 patients with CHB and 8 patients with AHB infection were included in the study. HBcAg-mediated induction of IL-18 was determined by quantitative reverse transcription-polymerase chain reaction (RT-PCR) and specific enzyme-linked immunosorbent assay (ELISA). HBcAg induced IL-18 gene transcription and dose-dependent secretion of mature IL-18 protein in HC, CHB, and AHB. HBcAg-dependent IL-18 levels were abrogated by inhibition of Caspase-1, but not by blockade of CD40-CD154 interaction. Serum levels of IFN-gamma correlated inversely with viremia in patients with CHB (rho = - 0.54, P < 0.05), but not with serum levels of IL-12 or IL-18. Interestingly, in PBMCs of HBeAg-negative patients, HBcAg induced significantly higher amounts of IL-18 than in those of HBeAg-positive patients. A variant, lacking the histone-like arginine-rich domain, did not induce IL-18 in either HC or CHB in vitro. Taken together, these results indicate that HBcAg induces IL-18 secretion by induction of Caspase-1. Differential regulation in HBeAg-negative and positive patients suggests an important role of IL-18 in CHB infection.

Liver cirrhosis after prolonged therapy with IFN-alpha plus interleukin-2 in a metastatic renal cancer long-term survivor

Interleukin-2 (IL-2) therapy is associated with serious toxic effects on the cardiopulmonary system. Less frequent toxicity is described in liver and the gastrointestinal system. A case of severe liver toxicity is described in a patient who underwent long-term immunotherapy with IL-2 (4.5 MU/m(2) s.c. daily, 5 days per week for 6 weeks, with 4 weeks of interval) plus interferon-alpha (IFN-alpha) (3 MU s.c. t.i.w., also covering the intervals between IL-2 cycles) for a metastatic renal carcinoma. A review of the literature is provided. The patient tolerated well the immunotherapy scheduled with apparently only a World Health Organization (WHO) G3 anemia and a G2 asthenia and is still alive, with a disease-free survival of 28 months. Notwithstanding a complete absence of liver function test abnormality during all scheduled clinical controls, the patient developed portal hypertension due to liver cirrhosis, which was histologically demonstrated. All common etiologic viral and toxic agents were ruled out. Long-term IL-2 therapy can induce liver cirrhosis. The appearance of liver and spleen enlargement during IL-2 therapy can be considered an indicator of liver damage. Thus, in this setting, closer monitoring is warranted despite normal liver function tests.

Type 1/Type 2 immunity in infectious diseases

T helper type 1 (Th1) lymphocytes secrete secrete interleukin (IL)-2, interferon-gamma, and lymphotoxin-alpha and stimulate type 1 immunity, which is characterized by intense phagocytic activity. Conversely, Th2 cells secrete IL-4, IL-5, IL-9, IL-10, and IL-13 and stimulate type 2 immunity, which is characterized by high antibody titers. Type 1 and type 2 immunity are not strictly synonymous with cell-mediated and humoral immunity, because Th1 cells also stimulate moderate levels of antibody production, whereas Th2 cells actively suppress phagocytosis. For most infections, save those caused by large eukaryotic pathogens, type 1 immunity is protective, whereas type 2 responses assist with the resolution of cell-mediated inflammation. Severe systemic stress, immunosuppression, or overwhelming microbial inoculation causes the immune system to mount a type 2 response to an infection normally controlled by type 1 immunity. In such cases, administration of antimicrobial chemotherapy and exogenous cytokines restores systemic balance, which allows successful immune responses to clear the infection.

A broad-spectrum caspase inhibitor blocks concanavalin A-induced hepatitis in mice

Fulminant hepatic failure (FHF) is a clinical syndrome resulting from massive death of liver cells or sudden and severe impairment of liver function. The causes of FHF are diverse and the overall mortality is very high. Recently, it became clear that apoptosis of hepatocytes is the critical cause of acute hepatic failure in FHF. It is well known that a family of cysteine proteases called caspase is one of the key mediators of the apoptotic pathway. Thus, caspases are attractive potential targets for the treatment of disorders resulting from excessive apoptosis. In this report, we examined the activity of a new caspase inhibitor, Xyz 033 mp. This nonpeptide inhibitor showed broad-spectrum caspase-inhibiting activity and protected primary rat hepatocytes from apoptotic death. In a mouse model of FHF induced by concavalin A (Con A), Xyz 033 mp suppressed elevated AST and ALT and specifically reduced IL-1 beta concentration. Also, Xyz 033 mp rescued mice from lethal experimental hepatitis induced by Con A. In addition, histological examinations indicated that Xyz 033 mp protected hepatocytes from the fatal apoptogenic effect of Con A. These results suggest that Xyz 033 mp may be a candidate therapeutic agent for FHF caused by massive apoptotic death of hepatocytes.

The impact of interferon gamma receptor expression on the mechanism of escape from host immune surveillance in hepatocellular carcinoma

Interferon gamma (IFN-gamma) plays an important role in host defense mechanism and participates in the progression of chronic liver disease. IFN-gamma exerts its pleiotrophic effects by transcriptional regulation of expression of numerous genes, such as major histocompatibility complex (MHC) class I and Fas, through interaction with IFN-gamma receptor (IFN-gamma-R). Although hepatocytes in normal liver express weak or no IFN-gamma-R, those in acute and chronic liver disease up-regulate its expression. A study using IFN-gamma-R alpha-chain knock-out mice revealed the actions of IFN-gamma on tumor cells as an extrinsic tumor-suppressor mechanism. However, it is unclear whether or how hepatocellular carcinoma (HCC) blocks the signal transduction of IFN-gamma to evade host immune surveillance. We examined the expression of IFN-gamma-R and IFN-gamma-inducible genes in 44 cases with HCC using real-time reverse-transcriptase polymerase chain reaction (RT-PCR) and immunohistochemistry. In noncancerous liver tissues (n = 38), IFN-gamma-R expression on the cell surface was up-regulated in 27 cases. In IFN-gamma-R-negative cases (n = 15), tumor size was larger (P =.032), serum alpha-fetoprotein (AFP) level was higher (P =.001), intrahepatic and extrahepatic metastasis was more common (P =.044 and.013, respectively), and Ki-67 labeling index (LI) was higher (P =.041), compared with IFN-gamma-R-positive cases. Accordingly, the evasion mechanism may play an important role in progression, especially metastasis, in HCC. The significant correlation between the status of IFN-gamma-R and the expression of Fas and MHC implies that the loss of IFN-gamma-R might contribute to the mechanism of escape from host immune rejection in HCC.

IFN-alpha receptor mRNA expression in a United States sample with predominantly genotype 1a/I chronic hepatitis C liver biopsies correlates with response to IFN therapy

Our aim was to assess whether, in the United States, with the predominant hepatitis C viral (HCV) genotypes 1a/I and 1b/II, hepatic interferon-alpha receptor (IFNAR) mRNA expression correlated with response to IFN therapy, levels of HCV RNA, or histologic activity index (HAI). Nine of 24 patients (38%) had an initial response to IFN treatment, 5 of whom (21%) had a sustained response. The corrected hepatic IFNAR mRNA expression (measured by RT-PCR) for the sustained responder group (mean +/- SE, 0.16 +/- 0.06, n = 5) was significantly higher than for the nonresponding group (0.059 +/- 0.01, n = 15) (p < 0.02). Patients who relapsed had an intermediate value (0.092 +/- 0.029, n = 4). Higher IFNAR expression was inversely correlated with a lower serum HCV RNA titer (p < 0.01), and responders to IFN treatment tended to have a lower titer of HCV RNA (p = 0.056). We found no significant correlation between the amounts of IFNAR with (1) the total HAI (low HAI < or = 7, IFNAR 0.076 +/- 0.013, n = 10; high HAI > or = 8, IFNAR 0.092 +/- 0.027, n = 14, ns) or (2) individual inflammation, necrosis, or fibrosis components of the HAI. As with Japanese HCV patients with genotypes 1b/II-2b/IV, higher hepatic IFNAR mRNA expression in the United States with predominant genotypes 1a/I and 1b/II appears to correlate with response to IFN therapy and a low HCV RNA titer but not with the total HAI or its components.

Involvement of Fas/Fas ligand system-mediated apoptosis in the development of concanavalin A-induced hepatitis

Concanavalin A (Con A)-induced hepatitis is an experimental hepatitis model in which hepatic injury is caused by the action of cytokines produced by T cells. Using IFN-gamma-deficient mice, we previously demonstrated that IFN-gamma plays a central role in Con A-induced hepatitis. Here, we show that development of the disease is completely suppressed in gld/gld mice, in which Fas ligand is defective. In contrast, suppression of the disease in Ipr/Ipr mice was incomplete, since a small amount of the fas mRNA was produced in these mice. The data indicate that activation of the Fas/Fas ligand system is a necessary step in the development of Con A-induced hepatitis. Furthermore, we found that not only fas but also caspase-1 expression was reduced in IFN-gamma-deficient mice. Since caspase-1 is an integral component of Fas signal transduction, these observations suggest that IFN-gamma-induced activation of both fas and caspase-1 expression causes enhancement of hepatocyte apoptosis resulting in the development of hepatitis.

The Secreted Hepatitis B Precore Antigen Can Modulate the Immune Response to the Nucleocapsid: A Mechanism for Persistence

The hepatitis B precore Ag (HBeAg) is a secreted nonparticulate version of the viral nucleocapsid hepatitis B core Ag (HBcAg), and its function is unknown. A proportion of HBeAg-specific Th cells evade deletion/anergy in HBeAg-transgenic (Tg) mice and mediate anti-HBe “autoantibody” (autoAb) production after in vivo activation with the appropriate Th cell peptide. This model system was used to determine how secretory HBeAg may effect deletion of Th cells in the periphery. For this purpose, HBeAg-Tg mice were bred with Fas and Fas ligand (FasL)-defective lpr/lpr and gld/gld mutant mice. Fas-FasL interactions mediate activation-induced apoptosis in the periphery. In HBeAg-Tg/+ mice, high-titrated anti-HBe autoAb was produced that was exclusively composed of the IgG1 isotype (i.e., Th2-like profile). In contrast, HBeAg-Tg/lpr and HBeAg-Tg/gld mice produced significantly less anti-HBe autoAb, and the IgG isotype patterns were broadened to include IgG2a, IgG2b and IgG3 as well as IgG1 (i.e., mixed Th1/Th2-like profile). These results suggest that HBeAg-specific Th1 cells are preferentially depleted by Fas-FasL-mediated interactions. The effect of circulating HBeAg on HBcAg-specific Th1 cells was also examined by transferring HBe/HBcAg-specific Th cells into dual HBeAg- and HBcAg-expressing Tg recipient mice. The presence of serum HBeAg ablated the expected Th1-mediated anti-HBc Ab response and shifted it toward a Th2 phenotype. These results suggest that in the context of a hepatitis B viral infection, circulating HBeAg has the potential to preferentially deplete inflammatory HBeAg- and HBcAg-specific Th1 cells that are necessary for viral clearance, thereby promoting hepatitis B virus persistence.

The hepatitis B virus core and e antigens elicit different Th cell subsets: antigen structure can affect Th cell phenotype

Secretion of the hepatitis B virus (HBV) e antigen (HBeAg) has been conserved throughout the evolution of hepadnaviruses. However, the function of this secreted form of the viral nucleoprotein remains enigmatic. It has been suggested that HBeAg functions as an immunomodulator. We therefore examined the possibility that the two structural forms of the viral nucleoprotein, the particulate HBV core (HBcAg) and the nonparticulate HBeAg, may preferentially elicit different T helper (Th) cell subsets. For this purpose, mice were immunized with recombinant HBcAg and HBeAg in the presence and absence of adjuvants, and the immunoglobulin G (IgG) isotype profiles of anti-HBc and anti-HBe antibodies were determined. Second, in vitro cytokine production by HBcAg- and HBeAg-primed Th cells was measured. The immunogenicity of HBcAg, in contrast to that of HBeAg, did not require the use of adjuvants. Furthermore, HBcAg elicited primarily IgG2a and IgG2b anti-HBc antibodies, with a low level of IgG3, and no IgG1 anti-HBc antibodies. In contrast, the anti-HBe antibody response was dominated by the IgG1 isotype; low levels of IgG2a or IgG2b anti-HBe antibodies and no IgG3 anti-HBe antibodies were produced. Cytokine production by HBcAg- and HBeAg-primed Th cells was consistent with the IgG isotype profiles. HBcAg-primed Th cells efficiently produced interleukin-2 (IL-2) and gamma interferon (IFN-gamma) and low levels of IL-4. Conversely, efficient IL-4 production and lesser amounts of IFN-gamma were elicited by HBeAg immunization. The results indicate that HBcAg preferentially, but not exclusively, elicits Th1-like cells and that HBeAg preferentially, but not exclusively, elicits Th0 or Th2-like cells. Because HBcAg and the HBeAg are cross-reactive in terms of Th cell recognition, these findings demonstrate that Th cells with the same specificity can develop into different Th subsets based on the structural form of the immunogen. These results may have relevance to chronic HBV infection. Circulating HBeAg may downregulate antiviral clearance mechanisms by virtue of eliciting anti-inflammatory Th2-like cytokine production. Last, the influence of antigen structure on Th cell phenotype was not absolute and could be modulated by in vivo cytokine treatment. For example, IFN-alpha treatment inhibited HBeAg-specific Th2-mediated antibody production and altered the IgG anti-HBe isotype profile toward the Th1 phenotype.

The effects of prednisolone and interferons on serum macrophage colony stimulating factor concentrations in chronic hepatitis B

BACKGROUNDS/AIMS

Serum concentrations of macrophage-colony stimulating factor (M-CSF) are increased in parallel with hepatic inflammation. The aim of this study was to assess the immunologic significance of elevated M-CSF in patients with chronic hepatitis B virus infection.

METHODS

The subjects included 20 asymptomatic HBV carriers and 45 patients with chronic hepatitis B, including 8 undergoing prednisolone treatment, 10 experiencing an acute exacerbation, and 12 undergoing daily administration of interferons.

RESULTS

Serum concentrations of M-CSF significantly decreased during prednisolone administration, but significantly increased following prednisolone withdrawal, similar to the increase during acute exacerbation. Changes in the lipopolysaccharide-stimulated production of interleukin-1-beta and tumor necrosis factor-alpha by peripheral whole blood, or of interferon-gamma by peripheral blood mononuclear cells showed a similar pattern. Serum concentrations of M-CSF did not correlate with the titers of HBV-DNA or HBV-DNA polymerase activity. However, serum M-CSF peaked preceding seroconversion to HBe antibody in three HBe antigen positive patients. Exogenous interferon-alpha, -beta, or -gamma induced significant elevation in serum M-CSF concentrations, irrespective of changes in the serum alanine aminotransferase levels.

CONCLUSIONS

Increased serum M-CSF is closely associated with increased serum interferons and/ or proinflammatory cytokines produced by peripheral blood cells during hepatic inflammation in chronic hepatitis B. This may be a consequence of the altered cytokine cascade resulting from the host immune response against hepatitis B virus.

Intrahepatic expression of pro-inflammatory cytokine mRNAs and interferon efficacy in chronic hepatitis C

To investigate the relationship between intrahepatic cytokine expression and interferon (IFN) response in chronic hepatitis C [CH(C)], interleukin (IL)-1 beta, -2, -4, -6, -8, interferon (IFN)-gamma, tumor necrosis factor (TNF)-alpha and TNF-beta mRNAs were investigated semiquantitatively by reverse transcription polymerase chain reaction using serial liver biopsies taken before and after IFN-alpha treatment from 24 patients with CH(C), including 12 responders and 12 non-responders. Before IFN treatment, IL-2, TNF-beta, IFN-gamma and IL-8 mRNA were associated with severe hepatitis activity whereas IL-4 mRNA was associated with weak hepatitis activity, regardless of IFN response. IL-2, TNF-beta and IFN-gamma mRNAs were significantly greater in IFN non-responders. After IFN treatment a complete response to IFN was significantly associated with the disappearance of these pro-inflammatory cytokines, whereas non-responders retained the expression of cytokine mRNA as before IFN treatment. Our results indicated that IFN-alpha treatment may modulate the intrahepatic cytokine network, and this may be one mechanism of IFN-alpha that reduces hepatitis activity, aside from an anti-viral effect. A difference in cytokine network may be involved in IFN response in CH(C).