Loss of HBsAg with interferon therapy in chronic hepatitis B virus infection

46 male chronic hepatitis B virus (HBV) carriers with active viral replication were randomised, with stratification for histology and sexual preference, to receive six months' lymphoblastoid interferon or no therapy. After nine to eighteen months' follow-up, HBeAg was no longer detectable and anti-HBe was present in 6 of the 23 treated patients. HBsAg was not detectable in 5 of these patients and 3 had anti-HBs. All of the controls remained positive for HBeAg and HBsAg. Seroconversion from HBeAg to anti-HBe was preceded in all cases by a pronounced increase in serum aspartate aminotransferase levels of more than ten times the upper limit of normal at eight to twelve weeks; this response was exclusively associated with interferon therapy. These results suggest that loss of HBsAg and a hepatitis-like illness in the third month of therapy are direct effects of interferon treatment.

Definition of hepatitis B virus (HBV)-specific target antigens recognized by cytotoxic T cells in acute HBV infection

We have investigated the specificity of cell-mediated cytotoxicity for autologous liver cells in 10 patients with acute hepatitis B in relation to the expression of hepatitis B virus (HBV) antigens and IgG on the surface of hepatocytes. Hepatitis B core antigen (HBcAg) was expressed on hepatocytes from six patients and hepatitis B surface antigen (HBcAG) from four, though always in association with HBcAg. Peripheral blood mononuclear cells (PBMC) were significantly cytotoxic in eight of the patients, and fractionation experiments revealed that the cytotoxic effect was equally mediated by T and non-T cells. Monoclonal antibody blocking experiments showed that HBcAg was the major target antigen recognized by T cells, although some inhibition of cytotoxicity was observed after pretreatment of target cells with monoclonal anti-HBs in patients with liver cell surface HBsAg. In contrast, non-T cells were not consistently inhibited by either monoclonal anti-HBc or anti-HBs. These findings further suggest that the HBV nucleoprotein serves as a target for recognition by cytotoxic T cells.

T-cell inducers of suppressor lymphocytes control liver-directed autoreactivity

The sensitisation of helper T cells of patients with autoimmune chronic active hepatitis to a liver-cell membrane-expressed asialoglycoprotein receptor protein is shown to be associated with a defect of T cells that specifically induce suppressor lymphocytes. These lymphocytes are found in an activated state in the peripheral blood of healthy people and may form part of an immunoregulatory network which actively prevents autoimmunity.

Failure of exogenous interleukin 1 and interleukin 2 to correct decreased lymphocyte transformation in chronic hepatitis B virus carriers

To test the hypothesis that reduced lymphocyte transformation in response to PHA in chronic hepatitis B virus infection might be due to deficient lymphokine production, lymphocyte transformation was measured in the presence or absence of exogenous interleukin 1, interleukin 2 or both, or, as a source of mixed lymphokines, supernatants from mixed lymphocyte reactions. The response to PHA was significantly impaired in patients compared to controls, but was not corrected by interleukin 1, interleukin 2 or supernatant from mixed lymphocyte reactions over a wide range of concentrations. Variation of the proportion of monocytes in culture or the addition of indomethacin had no effect on lymphocyte transformation. Thus, reduced lymphocyte proliferation in response to PHA in patients with chronic hepatitis B virus infection cannot be attributed to deficient lymphokine production or to active suppression by monocytes or prostaglandins and a direct role for the hepatitis B virus or a viral product is under investigation.

Hepatitis B vaccine: immunogenicity and follow-up including two year booster doses in high-risk health care personnel in a London teaching hospital

One hundred forty-four adult health care personnel (aged 18-62 years, median 33 years) considered at high risk of future HBV infection were vaccinated with a plasma-derived hepatitis B vaccine (20 micrograms HBVax at 0, 1, and 6 months) and followed-up for 2 years. Anti-HBs was present in only 6.9% prior to vaccination, and prescreening to detect this group would not have been cost-effective. At 9 months, 8.3% were nonresponders and a further 9% had anti-HBs levels less than 50 mIU/ml. Multivariate analysis showed that age was the single most important determinant of a poor response. In 47 of 52 individuals retested 2 years later, anti-HBs levels had fallen by 80% or more, and in four it had become undetectable. Response to a booster dose at this stage was excellent, with anti-HBs levels 3 months later much higher than at the end of the initial course. Additional booster doses of vaccine in two of the initial nonresponders at 14 and 22 months, respectively, also led to seroconversion. Although a significant proportion of health care workers in this study did not make a satisfactory response to the hepatitis B vaccine, later booster doses were very effective in subsequently increasing anti-HBs levels.

Controlled clinical trial of acyclovir in chronic hepatitis B virus infection

A randomised, controlled trial comparing acyclovir, 45 mg/kg/day as a continuous IV infusion for 28 days, with no other therapy, was carried out in 30 stable HBsAg carriers seropositive for HBeAg for more than 6 months. Twenty-eight had hepatitis B virus DNA-polymerase activity and/or hepatitis B virus DNA in serum at entry into the study. There were no significant adverse effects of therapy. At 12 months, seroconversion from HBeAg to anti-HBe had occurred in four of 15 treated patients, one of whom had also developed anti-HBs, compared with only one of 15 in the untreated group (95% confidence limits 12% and 51%). Seroconversion from HBeAg to anti-HBe was accompanied by return of serum liver function tests to normal and improved liver histology. The results of this study indicate that acyclovir is of no significant benefit in chronic HBeAg carriers with stable disease.

T-lymphocyte sensitization to hepatocyte antigens in autoimmune chronic active hepatitis and primary biliary cirrhosis. Evidence for different underlying mechanisms and different antigenic determinants as targets

Cultured with a liver-derived lipoprotein complex, T lymphocytes from 42 of 45 patients with autoimmune chronic active hepatitis generated migration inhibitory factor compared with 16 of 33 patients with primary biliary cirrhosis. Unlike T lymphocytes from patients with primary biliary cirrhosis, the T-cell reactivity of patients with chronic active hepatitis was always suppressed by T cells from normal subjects and, with two exceptions, by T cells from patients with primary biliary cirrhosis, even when these latter cells exhibited sensitization to this same antigen complex. Using a component of the whole complex, the asialoglycoprotein receptor as antigen, migration inhibitory factor was invariably released by T cells from patients with autoimmune chronic active hepatitis, but from only 2 of 8 patients with primary biliary cirrhosis sensitized to the whole complex. Thus, in autoimmune chronic active hepatitis, but not in primary biliary cirrhosis, the asialoglycoprotein receptor is invariably a target for cellular immune reactions and is associated with a suppressor T-cell defect for hepatocyte antigens.

In vitro study of IgG production and concanavalin A induced suppressor cell function in acute and chronic hepatitis B virus infection

To investigate the relationship between liver damage and immune regulation in hepatitis B virus (HBV) infection, 68 patients with HBsAg in serum and a spectrum of liver damage have been studied and compared with 25 controls. In HBsAg carriers, spontaneous IgG production was elevated only in those with chronic active hepatitis (P less than 0.05) whilst those with less severe inflammation had values comparable to normals. Concanavalin A (Con A) induced suppressor cell regulation of IgG producing cells was impaired in those with chronic active hepatitis (P less than 0.01) and those with chronic persistent hepatitis (P = 0.05) and there was a correlation in both groups of patients with the severity of portal tract inflammation (P less than 0.05). In contrast those with minimal liver damage had values in the normal range. Patients presenting with acute hepatitis B also had elevated spontaneous IgG production (P less than 0.01) and impaired Con A induced suppressor cell regulation of IgG production (P less than 0.01). Sequential study of three patients prior to the detection of HBsAg in serum and subsequently during and after acute hepatitis B showed that such abnormalities were transient and closely related to the onset of liver damage.

Interleukin 2 activity in chronic liver disease and the effect of in vitro alpha-interferon

To investigate mitogen induced helper interleukin 2 (IL-2) production in patients with chronic liver disease (CLD), IL-2 activity was assessed by an IL-2 bioassay using phytohaemagglutinin (PHA)-stimulated peripheral blood mononuclear cells (PBMNC). IL-2 activity was significantly reduced in patients with autoimmune chronic active hepatitis, primary biliary cirrhosis and alcoholic hepatitis with or without cirrhosis (P less than 0.01), and was comparable to controls in those with alcoholic cirrhosis alone. In vitro preincubation of PBMNC with lymphoblastoid alpha-interferon (alpha-IFN) before stimulation with PHA, led to a significant increase in IL-2 activity in all subjects (P less than 0.01), except those with alcoholic hepatitis, but in none of the groups did the levels of IL-2 activity reach those seen in normal subjects. The decrease in IL-2 activity in patients with CLD may be due to low IL-2 production or presence of an IL-2 antagonist(s). Such an abnormality may occur, not only as a result of liver damage, but may also be important in determining immunological disturbances involved in the pathogenesis of the liver disease.

The effect of prednisolone in vitro on immunoglobulin production in primary biliary cirrhosis

Immunoglobulin production and its regulation have been investigated in 36 untreated patients with primary biliary cirrhosis and 14 healthy controls. Using a haemolytic plaque assay, the number of cells spontaneously producing IgG or IgM was normal, while in contrast, proliferation of both IgG and IgM producing cells in the presence of pokeweed mitogen was impaired (P less than 0.01). There was in addition a defect of Con A induced suppression of proliferation of IgG and IgM producing cells (P less than 0.01), which was more marked in those with early disease than in those with advanced disease. In vitro incubation of mononuclear cells with prednisolone, 5 X 10(-8) M, corrected the defect of Con A induced suppression, but had no effect on spontaneous or pokeweed mitogen stimulated immunoglobulin production. Prednisolone was only effective if added prior to exposure to Con A. There is anecdotal evidence that corticosteroids may be beneficial in primary biliary cirrhosis and the results of the present study study suggest that further investigation of their role is warranted.

Functional characterization of peripheral blood lymphocytes in chronic HBsAg carriers

Increased proportions of suppressor/cytotoxic T cells have been identified in the peripheral blood of chronic HBsAg carriers and to investigate a possible relationship to T cell cytotoxicity against autologous hepatocytes, suppressor cell activity, viral replication and the histological type of disease, 42 consecutive HBsAg carriers undergoing a liver biopsy have been investigated. The proportion of suppressor/cytotoxic lymphocytes directly correlated with T cell cytotoxicity to autologous hepatocytes and both were higher in those with HBeAg in serum than in those with anti-HBe or those on corticosteroid therapy. There was no relationship to underlying histological classification. In contrast, suppressor cell regulation of IgG producing cells was unrelated to the proportion of suppressor/cytotoxic lymphocytes in peripheral blood or HBeAg status, but impaired function was associated with chronic hepatitis, particularly chronic active hepatitis. These data suggest that the increased proportion of suppressor/cytotoxic lymphocytes in the peripheral blood of HBsAg carriers represents an increase in the cytotoxic and not the suppressor cell subset and that this is a consequence of active viral replication and not of the severity of hepatic inflammation. Defective suppressor cell function may be one factor in the development of chronic active hepatitis, but is not reflected by alterations in the T4:T8 ratio.

In vitro effect of cyclosporin A on immunoglobulin production and concanavalin A induced suppression in primary biliary cirrhosis

The in vitro effect of Cyclosporin A on the regulation of immunoglobulin production was investigated in 16 patients with primary biliary cirrhosis. A significant improvement in concanavalin A induced suppression of IgG and IgM producing cells was observed after prior incubation of mononuclear cells with 300 ng/ml Cyclosporin A for 30 minutes. No effect was seen on spontaneous or pokeweed mitogen induced immunoglobulin production, nor on con A induced suppression if Cyclosporin A was added after 24 hours. Incubation of mononuclear cells with a variable dose of Cyclosporin A showed an effect only at 250-500 ng/ml. Higher and lower doses had no effect. This dose dependent effect of Cyclosporin A is likely to be related to a differential inhibitory effect on T helper and T suppressor cells and may underlie the clinical benefit being observed in current clinical trials.

Cell-mediated immunity and suppressor-T-cell defects to liver-derived antigens in families of patients with autoimmune chronic active hepatitis

By means of an indirect T-lymphocyte migration inhibitory factor assay, T-cell sensitisation to the asialoglycoprotein receptor, a liver-specific protein on the surface of hepatocytes, was found in patients with autoimmune chronic active hepatitis (CAH) but not in healthy relatives or spouses. Cellular immunity to a liver-derived lipoprotein complex (LSP) which also contains the asialoglycoprotein receptor, and to which immune reactions have been previously demonstrated in patients with CAH, was also examined. In contrast to the findings with the purified asialoglycoprotein receptor, cell-mediated sensitisation to LSP was detected in all the patients and also in 24% of first-degree relatives and 27% of spouses, suggesting an environmental influence. There was a functional defect in suppressor T lymphocytes specific for liver-derived antigens in 50% of first-degree relatives and 43% of second-degree relatives, but in only 9% of spouses. This abnormality of immunoregulation may be genetically determined and crucial to the development of the disease.

Ethanol metabolism in the generation of new antigenic determinants on liver cells

Antibodies directed against ethanol altered liver cell components have been detected in the serum of nearly 50% of patients with alcoholic liver disease although the pathogenetic mechanisms are unclear. The importance of ethanol metabolism in the generation of new antigenic determinants on liver cells was investigated by in vivo inhibition of alcohol or acetaldehyde dehydrogenase and an induced cytotoxicity assay. There was a significant reduction in cytotoxicity to hepatocytes isolated from rabbits treated with ethanol 1 g/kg when the metabolism of ethanol to acetaldehyde by alcohol dehydrogenase was inhibited. In contrast when the oxidation of acetaldehyde was inhibited by disulfiram cytotoxicity was significantly enhanced. These results show that ethanol metabolism is integral to the expression of the ethanol related determinant and suggest that an impaired ability to metabolism acetaldehyde could lead to the development of immunological reactions to alcohol altered liver membrane antigens.

A controlled trial of acyclovir in stable chronic HBsAg, HBeAg-positive carriers

Histological remission is recognised to follow loss of viral replication in chronic hepatitis B virus infection. The aim of antiviral therapies has been to accelerate seroconversion from HBeAg to anti-HBe, but so far none has been shown to be of significant advantage in adequate, controlled trials and toxicity has been common. A randomised controlled trial of acyclovir, 45 mg/kg/day by continuous intravenous infusion for 28 days versus no therapy has been completed in 30 patients positive for HBsAg and HBeAg for a minimum of 6 months. Patients were stratified for sex, histology and homosexual activity. Twenty-eight days therapy was associated with only a modest reduction in serum markers of viral replication. At 12-months DNAp was lost in 5/15 treated and 2/11 of the untreated group, while of the latter, 2 patients initially negative became positive. Seroconversion from HBeAg to anti-HBe had occurred in 4 of 15 treated and 1 of 15 untreated patients (95% confidence limits 12% and 51%) and was associated with histological improvement. Acyclovir had only a weak effect on viral replication and did not significantly accelerate the rate of seroconversion to anti-HBe.

Immunopathological mechanisms of liver cell injury in chronic hepatitis B virus infection

It is generally accepted that the hepatitis B virus is not cytopathic and that liver cell damage in chronic HBV infection is dependent on the host's immune response directed at viral and self-antigens on the surface of infected hepatocytes. In recent years there have been some advances in the understanding of both the viral antigen display on hepatocytes and the resultant host response. Using fluoresceinated polyclonal and monoclonal antibodies to HBV antigens, HBcAg has been identified as the major viral product expressed on the surface of liver cells isolated from patients with chronic HBV infection. In these patients, both T and non-T cells from peripheral blood have been shown to be cytotoxic to autologous hepatocytes. Blocking studies using polyclonal anti-HBs and anti-HBc antibodies indicate that HBcAg, but not HBsAg, is an important target antigen for T-cell attack, and this has recently been confirmed using monoclonal reagents. The non-T cell cytotoxicity appears to be directed at auto-antigens in a liver membrane lipoprotein complex (LSP), probably through an antibody-dependent (ADCC) mechanism. T-cell bypass mechanisms could be responsible for the production of autoantibodies to these normal membrane components. Both these mechanisms of cytolysis are found, most often, in patients with active viral replication in the HBeAg-positive phase of chronic HBV infection. This is presumably because hepatocytes containing free HBV-DNA and expressing HBcAg on their surface will be most susceptible to T-cell attack, while those with integrated HBV-DNA only express HBsAg and are relatively protected.(ABSTRACT TRUNCATED AT 250 WORDS)

T and B cell function in alcoholic liver disease

Increased in vivo synthesis of immunoglobulin in patients with alcoholic liver damage has been attributed to direct activation of B cells, although other defects of lymphocyte function have been identified suggesting a more generalised defect. In the present study we have investigated the role of T cell regulation of immunoglobulin production in alcoholic liver disease analysed according to the presence or absence of alcoholic hepatitis. Spontaneous production of IgG and IgA was elevated and co-culture experiments confirmed hyper-reactivity of B cells, but also suggested impaired T cell function. Suppressor cell activity for IgG and IgA was impaired. Similarly, the response to pokeweed mitogen for IgG and IgA was defective, although this was more marked for secretion than for proliferation suggesting an associated T helper defect. No differences in the immunological abnormalities were identified between those with alcoholic hepatitis and those with other alcoholic liver diseases. This study demonstrates a broad defect of T cells and a hyper-reactivity of B cells in patients with alcoholic liver disease, irrespective of the severity of hepatic inflammation.

In vitro effects of lymphoblastoid interferon on lymphocyte activation and cell-mediated cytolysis in patients with chronic hepatitis B virus infection

In addition to a direct anti-viral effect, interferons have important immunological properties including effects on cell-mediated immunity and antibody production as well as cell-mediated cytolysis. In chronic hepatitis B virus infection the host immune system is important for the elimination of replicating virus and in addition to directly inhibiting hepatitis B virus replication, interferons may affect host immune responses. We investigated the effect of lymphoblastoid interferon in vitro on lymphocyte activation and cell-mediated cytolysis in patients with chronic hepatitis B virus infection. The proliferative response to the mitogen PHA was significantly impaired in patients compared to controls. In addition supernatants of cultured mononuclear cells from patients stimulated with PHA contained less interleukin-2 activity than controls while the proportion of stimulated mononuclear cells expressing the interleukin-2 receptor was also reduced in patients. Prior incubation with 10(3) U ml-1 lymphoblastoid interferon increased both interleukin-2 activity and interleukin-2 receptor expression in patients and controls, although in patients the response was less marked. In contrast the proliferative response was unaffected. Natural killer cell activity against K562 cells was similar in patients and controls which in both groups was significantly augmented by prior incubation with 10(3) U ml-1 lymphoblastoid interferon; the increase was inversely proportional to baseline activity. In contrast incubation of target or effector cells with interferon did not augment T-cell cytotoxicity against autologous hepatocytes. The effects of lymphoblastoid interferon in vitro, were modest, but subtle changes in immunological status in addition to a direct effect on viral replication may be relevant to eventual clearance of the hepatitis B virus.

Differential effect of ARA-AMP on serum DNA polymerase activity and serum HBV-DNA in chronic hepatitis B virus infection. A possible reason for lack of efficacy

An uncontrolled pilot study of adenine arabinoside monophosphate intramuscularly (ARA-AMP) for 5 days at 10 mg/kg/day and 23 days at 5 mg/kg/day in divided doses, was conducted in 15 consecutive patients known to be HBeAg-positive for a minimum of 12 months. Two patients were lost to follow-up (1 having developed an hepatoma). Of the remaining 13, 11 remained HBeAg-positive at 1 year. During treatment, the median serum DNA polymerase (DNAp) activity fell from 592 cpm to 203 cpm/200 microliters. Of 12 patients initially positive for DNA polymerase, complete inhibition during treatment occurred in 6 and was permanent in 2, who developed anti-HBe. In the remaining 4 and in 6 further patients in whom inhibition was substantial but incomplete, DNAp activity rose to pretreatment levels within 1 month of completing treatment. All these patients remained DNAp + HBeAg-positive at one year. Serum HBV-DNA was measured in 7 patients, 6 who were initially DNAp-positive and 4 of whom had complete inhibition of DNAp during treatment. All 7 remained positive for HBV-DNA during treatment. Although side-effects were common there were no significant changes in biochemical or haematological parameters during or subsequent to therapy. Over the subsequent 48 months 2 more patients have developed an hepatoma and a further 5 have lost HBeAg; the 4 patients who remain alive and HBeAg-positive all had chronic persistent hepatitis initially.(ABSTRACT TRUNCATED AT 250 WORDS)

In-vitro cell-mediated cytotoxicity for autologous liver cells in chronic non-A, non-B hepatitis

To investigate the possible mechanisms of liver cell injury in chronic non-A, non-B (NANB) hepatitis, peripheral blood lymphocytes (PBL) from 16 patients with chronic NANB hepatitis were incubated with autologous hepatocytes in a microcytotoxicity assay. Significant cytotoxicity was demonstrated in 11 patients. T-enriched lymphocytes exhibited significantly greater cytotoxicity than non-T enriched cells. No significant inhibition of cytotoxicity was observed following preincubation of the liver cells with either monoclonal or polyclonal anti-HBc, or monoclonal anti-HBs, or addition of either purified HBsAg or recombinant HBcAg to the culture, indicating that there was no detectable cross-reactivity in this system between hepatitis B virus (HBV) and NANB-associated antigen(s). Preincubation of the patients' hepatocytes with polyclonal IgG purified from a serum of a patient who recovered from an acute NANB hepatitis, did not significantly alter cytotoxicity. Liver cell surface-bound IgG was detected by immunofluorescence in only two of the patients, a finding consistent with existing evidence of poor antibody responses to both liver membrane and NANB-associated antigens. Control experiments using PBL from allogeneic normal donors exhibited normal cytotoxicity for the patients' hepatocytes supporting the hypothesis that antibody-dependent cell-mediated cytotoxicity (ADCC) is unlikely to play a significant role in this clinical setting.