Hepatic interferon-alpha gene transcripts and products in liver specimens from acute and chronic hepatitis B virus infection

In this study we have examined the localization of interferon-alpha in liver tissue from acute and chronic hepatitis B virus carriers to establish whether the defect in interferon-alpha production reported in chronic hepatitis B virus infection is at a pretranscriptional or posttranscriptional level using in situ hybridization and immunohistochemical techniques. Interferon-alpha messenger RNA transcripts and the immunoreactive protein were abundant in liver tissue and in particular in hepatocytes from patients with acute hepatitis B virus infection who subsequently recovered. In contrast interferon-alpha polypeptide was present in a significantly lower number of sinusoidal cells, mononuclear cells and hepatocytes in chronic hepatitis B virus carriers. Although a high proportion of patients with chronic hepatitis B virus infection had cells that expressed interferon-alpha messenger RNA transcripts, the number of such cells was significantly less than in acute hepatitis B virus infection, indicating that the defect in the hepatic interferon-alpha synthesis is at the level of gene activation. Furthermore, using double immunohistochemical staining, the number of hepatocytes containing HBcAg correlated inversely with the proportion of neighboring sinusoidal cells expressing interferon-alpha. These data support previous observations that interferon-alpha production is reduced in chronic hepatitis B virus infection and are consistent with the view that this cytokine is important in the clearance of the virus.

Tumour necrosis factor production in fulminant hepatic failure: relation to aetiology and superimposed microbial infection

Tumour necrosis factor-alpha (TNF-alpha), a cytokine derived from macrophages, is considered to be an important endogenous mediator of endotoxic shock. Patients with fulminant hepatic failure are particularly susceptible to infection and the development of multi-organ failure and similarities to endotoxic shock suggest a possible pathogenetic role for TNF in fulminant hepatic failure. In vitro TNF production was therefore investigated serially in 21 consecutive patients with fulminant hepatic failure and in 21 healthy controls. Spontaneous and lipopolysaccharide-stimulated TNF production were elevated in viral-induced fulminant hepatic failure, compared with healthy controls (P less than 0.05 and P less than 0.01, respectively). By contrast, patients with paracetamol-induced fulminant hepatic failure had normal spontaneous and lipopolysaccharide-stimulated TNF production, while those who died had significantly reduced spontaneous TNF production compared with survivors (P less than 0.02); this difference was present throughout admission. In this group elevations in TNF production above baseline were associated with Gram-positive bacterial or fungal infection but not Gram-negative bacterial infection. There was no correlation between any of the clinical complications of fulminant microbial stimuli in fulminant hepatic failure, but do not support a direct role for TNF in the evolution of the clinical complications of fulminant hepatic failure.

Detection of hepatitis B virus antigens in liver tissue. A relation to viral replication and histology in chronic hepatitis B infection

The expression of hepatitis B virus antigens was studied by double staining liver tissue with appropriate antisera and correlated with serum hepatitis B viral DNA and histology in 28 patients with disease related to chronic hepatitis B virus infection. The cellular localization of hepatitis B core and hepatitis B e antigens generally coincided, but there were important differences at a subcellular level. Thus, hepatitis B e antigen was detected in nuclei and/or cytoplasm but strong cytoplasmic hepatitis B e antigen was associated with a high serum hepatitis B viral DNA (P = 0.0017) but not with active liver disease. Hepatitis B core antigen could also be detected in nuclei and/or cytoplasm, but strong cytoplasmic hepatitis B core antigen expression, exceeding that of hepatitis B e antigen, was associated with active liver disease (P = 0.041) and not with serum hepatitis B virus DNA. The proportion of hepatocytes expressing hepatitis B surface antigen correlated inversely with the serum titer (P = 0.0017), whereas hepatitis B surface and nucleocapsid antigens were usually expressed independently. The data support the hypothesis that cytoplasmic hepatitis B core antigen and not hepatitis B e antigen is the target for immune system-mediated cytolysis of hepatocytes. Cytoplasmic hepatitis B e antigen is not associated with liver damage but is instead associated with high levels of hepatitis B virus replication.

Patterns of cellular immune responses to thyrocyte membrane antigens and specific immunoregulatory defects in autoimmune thyroid disease

Although Graves' disease (GD), Hashimoto's thyroiditis (HT) and idiopathic myxoedema (Myx) are clinically distinct autoimmune thyroid diseases, previous studies using crude thyroid preparations as a source of antigens have failed to identify differences in cellular immune responses. In this study, we have assessed cellular immunity in patients with these disorders to two antigen preparations (derived from thyroid gland and cervical fat) enriched in cell membranes and known to share a functional TSH receptor. Using an indirect T-lymphocyte migration inhibitory factor (T-LIF) assay, T-cell immunity to thyroid membranes was demonstrated in 11/11 patients with GD, 4/5 with HT and 4/5 with Myx, but in none of 18 patients with chronic active hepatitis (another organ-specific autoimmune disease) or sixteen healthy controls. In contrast, T lymphocytes responsive to adipocyte membranes were detected only in patients with GD. TSH binding inhibiting antibodies were found exclusively in six patients with GD, and thyroid stimulating antibodies in five of these patients. In co-culture experiments designed to study the activity of antigen-specific suppressor T cells, low numbers of T cells from 6/6 normal controls, 4/4 patients with HT and 5/5 patients with myxoedema suppressed the response to adipocyte membranes of T lymphocytes from patients with Graves' disease. The results of this study demonstrate different patterns of T-cell reactivity to thyroid antigens in patients with Graves' disease, Hashimoto's thyroiditis and myxoedema and suggest that cellular immunity to the TSH receptor is restricted to patients with Graves' disease and associated with a defect in the specific immunoregulatory control of this response.

Spontaneous production of tumour necrosis factor alpha and interleukin-1 beta during interferon-alpha treatment of chronic HBV infection

Seven chronic carriers of hepatitis B virus (HBV) were studied during treatment with interferon-alpha to determine whether tumour necrosis factor alpha (TNF alpha) or interleukin-1 beta (IL-1 beta) contributed to the elimination of HBV. Four patients responded to interferon-alpha with clearance of HBeAg and permanent inhibition of HBV replication within 3-12 weeks; in each of these patients, the changes were accompanied by substantial rises in spontaneous in-vitro production of TNF alpha and IL-1 beta by peripheral blood mononuclear cells from previously undetectable levels. There was little or no change in spontaneous TNF alpha and IL-1 beta production in the three patients who did not lose HBeAg in response to interferon-alpha. These findings suggest that TNF alpha and IL-1 beta may contribute to the permanent elimination during interferon-alpha treatment of hepatocytes supporting viral infection and that the therapeutic potential of these cytokines is worthy of investigation.

The relationship between HLA-DR3 and T-cell regulation of immunoglobulin production in primary sclerosing cholangitis

Immunoglobulin production in vitro, its control by concanavalin A-activated suppressor T-cells, and the relationship between abnormalities in nonantigen-specific suppression and histocompatibility antigens have been studied in 20 patients with primary sclerosing cholangitis (PSC). Suppression of IgG, IgM, and IgA synthesis was impaired in 12 patients with PSC alone, but was normal in 8 with PSC and associated ulcerative colitis (UC). The HLA antigens B8 and DR3 were increased in frequency in both groups of patients, but an association between DR3, and to a lesser extent B8, and defective suppressor T-cell function was only observed in the patients with PSC alone. These results not only provide further evidence of an association between HLA DR3 and impaired nonantigen-specific suppression but also indicate the genetic complexity of this association and its specificity, being found in this study in only one subgroup of patients with PSC.

The natural history of hepatitis B virus infection

It was previously thought that two distinct types of chronic hepatitis B virus (HBV) infection existed. However recent evidence suggests that these are in fact phases in a continuous spectrum which evolves with time. Immediately after infection there is active viral replication. In patients infected in adult life, particularly in Europe and the USA, this is associated with varying degrees of liver damage. In those infected at birth, particularly in the Far East, there is initially much less inflammation with normal liver function. In succeeding years, viral replication decreases and liver damage increases with more deranged liver function test results. Eventually viral replication ceases and liver inflammation decreases, resulting in seroconversion with a loss of HBeAg and appearance of anti-HBe. Unfortunately, cirrhosis has already developed in some adults, with the increased risk of the later development of primary hepatocellular carcinoma. It is likely that there is a favourable window during the natural history of the infection when interferon is effective, probably in the few years immediately before spontaneous seroconversion.

Differential effect of alpha-interferons on CD4- and CD8-positive lymphocytes in chronic hepatitis B virus carriers

alpha-Interferons are an effective therapy in a proportion of chronic hepatitis B virus (HBV) carriers. The mode of action is almost certainly dependent upon immune modulation in addition to direct antiviral effects but the precise mechanism is unknown. To investigate whether the aberrant T-cell activation present in HBV carriers was responsive to interferons, we have studied the in vitro effect of alpha-interferons on Tac antigen expression and DNA synthesis as early and late markers of T-cell activation, respectively. At a concentration of 1000 U/ml the effect of alpha-interferons on Tac expression was contrasting in the two major T-cell subsets; there was enhancement of Tac expression on CD4-positive T-cells but inhibition of the CD8-positive subset. However, there was no overall effect on lymphocyte proliferation, perhaps as a consequence of the differential effect of alpha-interferons on the early T-cell activation marker. At higher concentration, however, the enhancement of T-cell activation was less clear, indicating that the concentration range that supports T-cell activation is narrow. Such subtle differential effects on T-cell activation may be accompanied by more profound effects on immune function and this may be one way in which alpha-interferons are of value in chronic HBV infection.

Enhanced tumour necrosis factor and interleukin-1 in fulminant hepatic failure

Sepsis and endotoxaemia are common in fulminant hepatic failure (FHF) and may contribute to multisystem disease in such patients. Tumour necrosis factor (TNF) is a probable mediator of endotoxic shock and infusion of this monokine into animals causes multi-organ failure that shares features with FHF. In patients with FHF, TNF production was increased and correlated closely with activity of interleukin-1, another cytokine that is released by monocytes/macrophages in response to infection and endotoxin and is produced in increased quantities in FHF. Interleukin-2 activity was impaired in FHF and correlated negatively with TNF production.

In situ hybridisation in formalin fixed, paraffin wax embedded liver specimens: method for detecting human and viral DNA using biotinylated probes

A rapid and reproducible technique for in situ hybridisation, using biotin labelled probes for the Y chromosome, human DNA, hepatitis B virus DNA and cytomegalovirus DNA on formalin fixed, paraffin embedded liver tissue, was developed. The degree of proteolytic digestion of tissue specimens is critical to ensure adequate unmasking of DNA and to avoid non-specific staining, a consequence of endogenous biotin in liver. Specific in situ hybridisation was achieved after digestion with pepsin, proteinase K, or protease, which gave optimal results. Both hepatitis B virus DNA and cytomegalovirus DNA were visualised in tissue from patients with chronic hepatitis B virus infection or in liver transplant recipients, respectively; the distribution of viral DNA was shown to be quite distinct between the two groups of patients.

An enzyme immunoassay for the measurement of HLA-DR antigen expression

A simple, sensitive, rapid and reproducible method is described for the measurement of HLA-DR expression on monocytes. The assay is based on an enzyme-linked immunostaining of the cells in suspension form followed by colour development. The non-specific binding of anti-HLA-DR to Fc receptors was taken into account by incubation of cells with an irrelevant monoclonal antibody (antirubella-G7H9). The binding of the anti-rubella monoclonal with the cells was subtracted from the binding of anti-HLA-DR to cells. Using three different cell lines (K562, CTLL and Daudi), the specificity of the assay proved to be acceptable and the assay remained sensitive even when only 10(4) cells/well were used. The assay has a number of potential applications.

Serial study of liver-directed autoantibodies and autoreactive T-lymphocytes in acute viral hepatitis B

To explore the mechanisms underlying liver-directed autoimmune reactions in acute Hepatitis B Virus (HBV) infection, we followed five subjects who were identified in the early incubation phase (30-70 days before the first elevation of transaminases). We assessed serially cellular (using a T-lymphocyte migration inhibitory factor assay) and humoral (RIA) immunity to LSP (a macromolecular, liver-derived lipoprotein complex) and hepatic lectin (HL), the liver-specific receptor for desialylated glycoproteins, which appears to be a major target antigen for autoreactions in autoimmune chronic active hepatitis. Anti-LSP and anti-HL autoantibodies were found, at some stage during acute HBV infection, in 4/5 subjects, whereas cellular immunity to the same antigens was detected in only two patients. Sustained production of anti-HL antibodies was noted only in patients showing cellular immunity to this antigen and was apparently secondary to liver damage, whereas anti-LSP antibodies were first detected at the onset of liver injury when there was no evidence of T-cell immunity to the same antigenic complex. One explanation for this apparent dichotomy between cellular and humoral responses to LSP is that a helper T-cell response to the major envelope component of HBV, HBsAg, which precedes by 10-20 days the development of anti-LSP antibodies, promotes a humoral reaction to autoantigens contained in the LSP preparation, coexpressed with HBsAg, on the surface of infected hepatocytes.

Clearance of pre-S2 antigen: a marker of successful interferon therapy in hepatitis B virus infection

The relation between viral replication, the presence of HBsAg and pre-S2 in serum and eventual clinical outcome has been investigated in fourteen patients undergoing treatment with lymphoblastoid interferon for chronic hepatitis B virus (HBV) infection. In four patients permanent loss of pre-S2 was accompanied by loss of serum HBV-DNA in association with a marked elevation of serum aspartate aminotransferase activity and in each of these cases HBsAg was subsequently cleared from serum. In contrast there was no significant fluctuation in the concentration of either pre-S2 or HBsAg in four cases not responding to therapy although substantial or complete inhibition of viral replication had been observed during treatment. In the third group, permanent loss of HBV-DNA was observed but in these cases pre-S2 and HBsAg persisted in serum, albeit at lower concentrations, while in this group loss of HBV-DNA from serum was not accompanied by a flare in disease activity. These results suggest first, that assay of pre-S2 is a further measure of the response to interferon and second that in some cases interferon enhances immune recognition of both the pre-S2 and HBsAg polypeptides.

Interleukin-1 and interleukin-2 activity in chronic hepatitis B virus infection

Abnormalities of lymphocyte proliferation in chronic hepatitis B virus infection are well documented, although the underlying mechanisms are poorly understood. To determine whether these defects may be secondary to disordered lymphokine production, we have simultaneously assayed interleukin-1 and interleukin-2 production in 31 chronic carriers of the hepatitis B virus. Supernatants from mononuclear cells cultured both in the presence and absence of lipopolysaccharide contained significantly increased quantities of interleukin-1 activity in patients compared with normal controls (p less than 0.01). Lysates of monocytes from patients also contained more interleukin-1 than those of controls (p less than 0.05) in the presence of lipopolysaccharide or silica, or both. These results indicate that interleukin-1 production is markedly elevated in patients with chronic hepatitis B virus infection, whereas in contrast, interleukin-2 production was found to be reduced in these patients (p less than 0.01). As one of the biological properties of interleukin-1 is to stimulate fibroblasts to produce collagen, the relationship between fibrosis in the liver biopsy specimen and interleukin production was examined. There was a highly significant correlation (p less than 0.001) between interleukin-1 production and the severity of fibrosis, suggesting that this lymphokine may be closely related to the development of cirrhosis in such patients.

Sequential studies of pre-S2 antigenemia and anti-pre-S2 antibodies in relation to viral replication in acute hepatitis B followed from the early incubation phase

To determine the time sequence of expression of pre-S2 peptide (120-150) during the presymptomatic phase of acute hepatitis B, we used a monoclonal antibody radioimmunoassay in five subjects followed from 30 to 70 days before the onset of liver damage. Pre-S2 peptide was present in serum at low levels from the early incubation phase and started to increase immediately after the first detection of HBV-DNA in serum, in parallel with the increase in HBsAg levels. During the symptomatic phase, levels of pre-S2 peptide declined rapidly; it was no longer detectable after recovery. Anti-pre-S2 antibodies were detected, in four patients, only in the recovery phase. These results demonstrate that expression of pre-S2 peptide occurs very early in the incubation phase of acute HBV infection and is cleared in parallel with HBsAg. Anti-pre-S2 antibodies seem to play no role in viral clearance in these patients.

In vitro effect of TP-1 (a calf thymic extract) on suppressor T-cell function of patients with autoimmune chronic active hepatitis

Concanavalin A-activated T-lymphocyte suppression of IgG production was found to be significantly impaired in patients with untreated active autoimmune chronic hepatitis when compared to normals or patients with inactive disease. When the dose-response effect of TP-1, a calf thymic extract, on in vitro suppressor cell activity was assessed, lymphocytes from six out of eight patients with previously reduced suppressor cell function showed a significant improvement, while over a similar range the suppressor cell activity of most normal controls declined. These results support the possibility that defective immunoregulation in patients with autoimmune chronic active hepatitis may be related to a deficiency in thymic hormone levels.

Cellular immunity to nucleocapsid and pre-S determinants in asymptomatic carriers of hepatitis B virus

Previous studies of cellular immunity in asymptomatic HBV carriers have been limited to evaluation of responses to plasma-derived HBsAg preparations. We have explored the specificity of cellular immune responses to HBV antigens in these subjects using an indirect T-lymphocyte migration inhibitory factor assay and three antigen preparations (recombinant nucleocapsid antigen (HBcAg), plasma-derived HBsAg with or without pre-S2, and Saccharomyces cerevisiae-synthesized HBsAg without pre-S2 region). T cells from 10 asymptomatic chronic HBV carriers with normal liver function tests were responsive to nucleocapside determinants (mean migration index = 0.55 +/- SD 0.07) and to pre-S2-positive plasma-derived HBsAg (MI = 0.62 +/- 0.05). However, none responded to HBsAg devoid of pre-S2 sequences (MI = 0.98 +/- 0.04). In further experiments, T cells from three HBV carriers, cultured with six different HBsAg preparations, exhibited responsiveness only to those preparations containing significant pre-S2 activities. Our results show that T-cell immunity to nucleocapsid determinants of the virus and HBsAg in present in asymptomatic HBV carriers; the latter is restricted to antigenic preparations containing significant pre-S2 activities. Hence, T-cell immunity to pre-S determinants may not always be associated with HBV clearance.

Immunoglobulin on the surface of isolated hepatocytes is associated with antibody-dependent cell-mediated cytotoxicity and liver damage

Hepatocytes isolated from patients with chronic liver disease are often covered by immunoglobulin. The aim of the present study was to establish whether this surface immunoglobulin (SIg) mediates liver cell damage. Freshly isolated hepatocytes from percutaneous liver biopsy of 16 patients with chronic active hepatitis (CAH) (6 HBsAg positive), 3 with HBsAg-positive chronic lobular hepatitis (CLH), 5 with HBsAg-positive chronic persistent hepatitis (CPH) and 12 with minor histological abnormalities (MHA) (5 HBsAg positive) were divided into two aliquots. One was studied for the presence of membrane-bound immunoglobulin and the third component of complement by direct immunofluorescence and the other was incubated, in an allogeneic cytotoxic assay, with peripheral blood mononuclear cells prepared from healthy volunteers as a source of effectors for antibody-dependent cell-mediated cytotoxicity (ADCC). Liver biopsies were scored for portal and parenchymal inflammatory activity. The percentage of SIg positive hepatocytes was significantly higher in patients with CAH (median 52.5%) than in patients with CLH/CPH (20.5%) or in patients with MHA (1%). Percentages of SIg-positive liver cells were significantly correlated with total liver biopsy scores and with both portal or parenchymal scores considered independently. SIg were found to belong to the IgG class in all groups of patients. When hepatocytes were cultured with normal human lymphocytes, allogeneic cytotoxicity values were significantly higher in patients with CAH (median 34%) than in patients with CLH and CPH (18%) or in those with MHA (12%). Percentage cytotoxicity was positively correlated with total biopsy scores and with portal activity but not with parenchymal activity, suggesting that ADCC might play a damaging role mainly in the portal areas.(ABSTRACT TRUNCATED AT 250 WORDS)

Prospective study of cellular immunity to hepatitis-B-virus antigens from the early incubation phase of acute hepatitis B

Cellular immunity to hepatitis-B-virus (HBV) antigens was followed prospectively in five patients who were identified in the early incubation phase of acute HBV infection, between 30 and 70 days before the onset of liver damage. Cellular immunity to pre-S antigens was the first detectable immune response, appearing 30 days before the first rise in serum aminotransferases in every case. T-cell sensitisation to HBcAg followed, with IgM anti-HBc appearing 10 days later. A cellular immune response to HBsAg was the last to appear, 10 days before the onset of liver damage. These cellular immune responses are the earliest host responses to the virus infection and could be critical in initiating and directing the processes of liver damage and viral clearance.