Monocyte-derived dendritic cells from HCV-infected patients transduced with an adenovirus expressing NS3 are functional when stimulated with the TLR3 ligand poly(I:C)

Dendritic cells (DC) transfected with an adenovirus encoding hepatitis C virus (HCV) NS3 protein (AdNS3) induce potent antiviral immune responses when used to immunize mice. However, in HCV infected patients, controversial results have been reported regarding the functional properties of monocyte-derived DC (MoDC), a cell population commonly used in DC vaccination protocols. Thus, with the aim of future vaccination studies we decided to characterize MoDC from HCV patients transfected with AdNS3 and stimulated with the TLR3 ligand poly(I:C). Phenotypic and functional properties of these cells were compared with those from MoDC obtained from uninfected individuals. PCR analysis showed that HCV RNA was negative in MoDC from patients after the culture period. Also, phenotypic analysis of these cells showed lower expression of CD80, CD86, and CD40, but similar expression of HLA-DR molecules as compared to MoDC from uninfected individuals. Functional assays of MoDC obtained from patients and controls showed a similar ability to activate allogeneic lymphocytes or to produce IL-12 and IL-10, although lower IFN-alpha levels were produced by cells from HCV patients after poly(I:C) stimulation. Moreover, both groups of MoDC induced similar profiles of IFN-gamma and IL-5 after stimulation of allogeneic T-cells. Finally, migration assays did not reveal any difference in their ability to respond to CCL21 chemokine. In conclusion, MoDC from HCV patients are functional after transduction with AdNS3 and stimulation with poly(I:C). These findings suggest that these cells may be useful for therapeutic vaccination in chronic HCV infection.

Altered expression and activation of signal transducers and activators of transcription (STATs) in hepatitis C virus infection: in vivo and in vitro studies

BACKGROUND

Signal transducers and activators of transcription (STATs) play a critical role in antiviral defence. STAT3 is also important in cell protection against inflammatory damage. STAT proteins are activated by interferons and by hepatoprotective cytokines of the interleukin 6 superfamily, including cardiotrophin 1.

METHODS

We analysed the status of STATs in hepatitis C virus (HCV) infected livers and the relationship between expression and activation of STATs and HCV replication in Huh7 cells transfected with HCV genomic replicon.

RESULTS

STAT3alpha expression was reduced in HCV infected livers showing an inverse correlation with serum alanine aminotransferase. In patients with HCV infection, nuclear staining for phosphorylated STAT3 was faint in parenchymal cells (although conspicuous in infiltrating leucocytes), in contrast with strong nuclear staining in hepatocytes from control livers. Expression and activation of STAT1 (a factor activated by both interferon (IFN)-alpha and IFN-gamma) were increased in HCV infected livers, particularly in those with high inflammatory activity. Conversely, phosphorylated STAT2 (a factor selectively activated by IFN-alpha) was undetectable in livers with HCV infection, a finding that was associated with marked downregulation of the two functional subunits of the IFN-alpha receptor. HCV replication in Huh7 cells caused STAT3alpha downregulation and blocked STAT3 phosphorylation by either IFN-alpha or cardiotrophin 1. HCV replication in Huh7 cells also inhibited STAT1 and STAT2 activation by IFN-alpha while there was no impairment of STAT1 phosphorylation by the proinflammatory cytokine IFN-gamma.

CONCLUSIONS

STAT3 is downregulated in HCV infected livers and in Huh7 cells bearing the full length HCV replicon. HCV replication is associated with impaired Jak-STAT signalling by antiviral and cytoprotective cytokines. These effects may favour viral replication while facilitating the progression of liver disease.

Characterization of T-cell responses against immunodominant epitopes from hepatitis C virus E2 and NS4a proteins

Successful clearance of hepatitis C virus (HCV) infection has been associated with strong cellular immune responses against viral antigens. However, although the magnitude of these responses is clearly important for viral eradication, more studies are needed to unravel the fine specificity of the protective anti-HCV immunity in infected patients. This was the aim of the present study. Overlapping peptides spanning the sequence of HCV E2 and NS4a proteins were used to stimulate T cells from patients with chronic hepatitis C divided into three groups: naïve patients, patients who exhibited sustained response to interferon (IFN)-alpha therapy and patients who failed to respond to the treatment. Interleukin-2 production by stimulated cells was measured in each case. Patients with sustained response to therapy had stronger responses to E2 peptides than nonresponders, whereas naïve patients demonstrated intermediate reactivity. In the case of NS4a, responses against peptides where similar in all groups of patients. Analysis of the peptides recognized by T cells showed that responses were broad and heterogeneous, and some immunodominant epitopes, preferentially recognized by patients exhibiting sustained response to treatment, were found. These results confirm the role of cellular immune responses in viral clearance, and stress the importance of immunodominant regions within HCV antigens. These viral sequences may represent valuable immunogens for preparation of therapeutic or prophylactic vaccines.

Nuclear factor-kappa B in the liver of patients with chronic hepatitis C: decreased RelA expression is associated with enhanced fibrosis progression

The mechanisms of liver damage in chronic hepatitis C virus (HCV) infection are poorly understood. The transcription factor, nuclear factor-kappa B (NF-kappa B), regulates the expression of genes involved in apoptosis, inflammation, and antiviral response. It plays a protective role in several forms of liver damage. In this study, we analyzed NF-kappa B by gel mobility shift assay and immunohistochemistry in liver biopsies from HCV-infected patients, and we have determined the hepatic levels of the components of the NF-kappa B system by semiquantitative polymerase chain reaction (PCR). We found that NF-kappa B was activated in the liver of patients with chronic hepatitis C. Neither NF-kappa B activity nor the RNA levels of NF-kappa B subunits showed correlation with liver inflammatory activity, viral load, or HCV genotype. By contrast, hepatic mRNA values of RelA, the main element of active NF-kappa B, correlated inversely with apoptosis (r = -.68; P <.05) and with the rate of fibrosis progression (r = -.51; P <.04). In intermediate/rapid fibrosers, RelA mRNA levels were significantly decreased as compared with slow fibrosers (P <.003) and with normal livers (P <.03). In conclusion, we found that NF-kappa B is activated in chronic HCV-infected livers, and that the expression of RelA is inversely correlated with liver cell apoptosis and with the rate of fibrosis progression. Our data thus suggest that RelA expression may protect against liver fibrosis and hepatocellular damage.

Expression of interferon-alpha subtypes in peripheral mononuclear cells from patients with chronic hepatitis C: a role for interferon-alpha5

Interferon (IFN)-alpha is a family of antiviral proteins encoded by different genes. The biological significance of the existence of various IFN-alpha subtypes is not clear. We have investigated the interferon system in chronic hepatitis C virus (HCV) infection, a disease that responds to interferon-alpha2 therapy in only a limited proportion of cases. We analysed the expression of interferon regulatory factor (IRF)-1, IRF-2, and IFN-alpha subtypes in nonstimulated and Sendai virus-stimulated peripheral blood mononuclear cells (PBMC) from HCV infected patients and healthy controls. We observed that the IRF-1 mRNA and IRF-1/IRF-2 ratios were increased in PBMC from hepatitis C patients with respect to normal subjects. Sendai virus stimulation of PBMC led to a significant increase in the levels of IRF-1, IRF-2 and IFN-alpha mRNAs and in the production of IFN-alpha protein with respect to basal values in healthy controls as well as in patients with HCV infection. In addition, we found that while natural HCV infection induced increased IFN-alpha5 expression in PBMC, in vitro infection of these cells with Sendai virus caused a raise in the expression of IFN-alpha8 in both patients and normal controls. In summary, our results indicate that virus-induced activation of the IFN system in human PBMC is associated with selective expression of individual IFN-alpha subtypes, IFN-alpha5 being the specific subtype induced in PBMC from patients with chronic HCV infection.

Pathological and virological findings in patients with persistent hypertransaminasaemia of unknown aetiology

BACKGROUND

The histopathological spectrum and role of hepatitis viruses in cases of hypertransaminasaemia of unknown aetiology have not been correctly analysed in a sufficiently large number of patients.

METHODS

We studied 1075 consecutive patients referred for liver biopsy because of elevation of alanine aminotransferase (ALT) levels for more than six months. From this population we selected those cases in whom the aetiology could not be defined from clinical, biochemical, and serological data obtained before biopsy. In these patients liver biopsies were reviewed, and hepatitis B virus (HBV)-DNA and hepatitis C virus (HCV)-RNA were assayed in serum by polymerase chain reaction (PCR). Serum hepatitis G virus (HGV)-RNA was determined by PCR in 74 patients.

RESULTS

Of 1075 patients studied, the cause of the increased serum ALT levels remained elusive after appropriate testing in 109 patients (10.1%). Liver biopsies from these patients showed non-specific changes in 32.7% of cases, non-alcoholic steatohepatitis (NASH) in 15.8%, and chronic hepatitis or cirrhosis in 51.5%. HBV-DNA and/or HCV-RNA was detected more frequently in cryptogenic liver disease than in healthy blood donors (26.7% v 3.4%; p<0.001). HGV-RNA was found in only one patient. The proportion of cases with detectable HBV-DNA or HCV-RNA was 14.3% in patients with non-specific changes or NASH, 30.7% in patients with chronic hepatitis, and 61.5% in patients with cirrhosis. Cirrhosis was found more frequently in patients with positive HBV-DNA and/or HCV-RNA in serum than in those who tested negatively (p=0.005).

CONCLUSIONS

In our series, patients in whom biochemical and serological data did not determine the aetiology of the disease represented 10% of all cases referred for liver biopsy for persistent elevation of serum transaminases. Approximately 50% of patients had chronic hepatitis or cirrhosis and the remainder had NASH or non-specific changes. Occult viral infections were found in a high proportion of cases in the first group and in a low percentage of patients in the second.

Early predictors of response to treatment in patients with chronic hepatitis C

The term sustained response should be applied to patients with negative serum HCV-RNA and normal values of serum transaminases 6 months after interferon withdrawal. To investigate which factors identify sustained responders early during treatment we analysed 18 reports which used the definition sustained response. Eight reports, comprising 988 patients, have studied the value of early clearance of viraemia as a predictor of sustained response using multivariate analysis and all of them found that this was the strongest predictor of a sustained response. Determination of HCV-RNA 4 or 12 weeks after initiation of IFN therapy predicts treatment outcome more accurately than baseline viral load (the best pre-treatment predictor). ALT levels during the first 12 weeks of treatment have lower predictive value than early viral clearance. The sensitivity of a negative HCV-RNA test is similar at week 4 and at week 12 of therapy while the specificity and the accuracy is higher at week 4. The value of persistent viraemia for early prediction of no response is higher than 97%, with similar values at weeks 4 and 12. Persistence of HCV-RNA in serum at week 4 strongly indicates that the patient will not respond to treatment and in these cases interruption of treatment or other therapeutic options could be considered.

Antioxidant status and glutathione metabolism in peripheral blood mononuclear cells from patients with chronic hepatitis C

BACKGROUND/AIMS

Oxidative stress could play a role in the pathogenesis of hepatitis C virus infection. We investigated the oxidant/antioxidant status in peripheral blood mononuclear cells from patients with chronic hepatitis C and controls.

METHODS/RESULTS

Lipid peroxidation products and superoxide dismutase activity in peripheral blood mononuclear cells were higher in chronic hepatitis C patients than in healthy subjects while glutathione S-transferase activity was reduced in patients as compared to controls. Catalase, glutathione peroxidase and glutathione reductase were similar in chronic hepatitis C and normal individuals. No statistically significant differences were found between patients and controls with regard to glutathione levels in peripheral blood mononuclear cells, but 35% of patients with chronic hepatitis C showed values of glutathione and oxidized glutathione which were below and above, respectively, the limits of normal controls. Finally, the glutathione synthetic capacity of the cytosol of peripheral blood mononuclear cells was significantly higher in patients than in controls, indicating increased glutathione turnover in lymphocytes from patients with chronic hepatitis C.

CONCLUSIONS

Oxidative stress is observed in peripheral blood mononuclear cells from chronic hepatitis C patients. This process might alter lymphocyte function and facilitate the chronicity of the infection.

Interferon alfa subtypes and levels of type I interferons in the liver and peripheral mononuclear cells in patients with chronic hepatitis C and controls

Viral infections stimulate the transcription of interferon type I, which includes IFN-alfa (IFN-alpha) (13 subtypes) and IFN-beta (a single substance). Hepatitis C virus (HCV) infection is remarkable by its ability to evade host antiviral defenses; however, there is little information as to whether endogenous IFN is activated or not in this disease. Additionally, despite the fact that the various IFN-alpha subtypes may differ in biological activity, there are no data concerning the IFN-alpha subtypes specifically expressed in normal and diseased liver tissue. Thus, we have analyzed the IFN-alpha subtypes and the mRNA levels of type I IFNs in samples of normal liver tissue and in liver from patients with chronic hepatitis C. Similar studies were performed in peripheral blood mononuclear cells (PBMC) from patients and controls. After amplification and cloning of IFN-alpha cDNA, we observed that 98 of the 100 clones from normal liver tissue corresponded to the IFN-alpha5 subtype. However, in livers with chronic hepatitis C and in PBMC from controls and patients, a variety of subtypes, in addition to IFN-alpha5, were detected, suggesting a participation of infiltrating leukocytes in the production of IFN-alpha in livers with chronic hepatitis C. As compared with controls, patients with chronic hepatitis C showed a significant increase in IFN-beta mRNA in both the liver and PBMC, while IFN-alpha mRNA was significantly increased in PBMC but markedly reduced in liver tissue. In conclusion, IFN-alpha5 is the sole IFN-alpha subtype expressed in normal liver tissue. The hepatic levels of IFN-alpha are reduced in chronic hepatitis C, an event that may favor viral persistence.

Immunogenicity of variable regions of hepatitis C virus proteins: selection and modification of peptide epitopes to assess hepatitis C virus genotypes by ELISA

The immunogenicity of variable regions of hepatitis C virus (HCV) proteins was studied by ELISA by using 543 synthetic peptides from 120 variable regions and 90 sera from HCV-infected patients. Some regions from certain genotypes were less immunogenic, or even non-immunogenic, compared with their equivalents in other genotypes. However, the mean recognition of all peptides from genotypes 1a, 1b and 3 by sera infected with genotypes 1a, 1b and 3, respectively, showed no significant differences, suggesting a similar overall immunogenicity of variable regions from these genotypes. Proteins NS4a, NS4b and NS5a were found to be the most immunogenic. Recognition of individual peptides by the sera of infected patients showed that the humoral response against HCV is patient-dependent. The work shows that 15-mer peptides may encompass several B-cell epitopes. These epitopes may lie in slightly different positions in different genotypes. Thirty-one percent of the 543 peptides were recognized by some of the 35 healthy donors. This may be a reflection of the large number of antigens to which they had been exposed, but it may also reflect a strategy of HCV to respond to immune pressure. After selection and modification, a set of 40 peptides was used to assess genotypes 1a, 1b, 1, 2 and 3 in the sera of HCV-infected patients, with sensitivities of 34.1, 48.5, 68.8, 58.3 and 48.9% and specificities of 100, 99.1, 97.1, 99.5 and 99%, respectively. The overall sensitivity and specificity for the assessment of genotypes 1, 2 and 3 were 64 and 98%, respectively.

Cellular immunity to hepatitis C virus core protein and the response to interferon in patients with chronic hepatitis C

To investigate the involvement of T-cell response against hepatitis C virus (HCV) antigens in viral clearance after interferon therapy, we measured interleukin-2 (IL-2) production by peripheral mononuclear cells in response to HCV core in patients with chronic hepatitis C. In a cohort of 43 patients, we investigated the frequency of circulating core-specific T-helper (Th) cell precursors by the limiting-dilution assay, and in a second cohort of 60 patients, we analyzed the response to specific core epitopes using 52 synthetic 15-mer overlapping peptides. We observed that the frequency of core-specific Th cell precursors was significantly higher in patients with sustained biochemical and virological response (SR) after interferon (IFN) therapy (median, 1/55,736) than in untreated patients (1/274,023) or that in patients who remained viremic after completion of the treatment-nonresponders (NR) plus transient responders (TR) (1/1,909,972). Patients who failed to respond to IFN (NR) and those who relapsed after IFN discontinuation (TR) had a similarly low number of precursors. The number of core peptides recognized by SR, TR, NR, UT, and healthy controls was 8.2 +/- 1.5, 6.5 +/- 1.2, 2.0 +/- 0.5, 2.7 +/- 0.9, and 0.3 +/- 0.2, respectively. In SR, the intensity of the proliferative response to core peptides as estimated by the summation of stimulation indexes (sigmaSI) was significantly higher than in NR and than in UT, but not different from that of TR. Our results indicate that both expansion of HCV-specific Th cell precursors and Th cell recognition of multiple core epitopes seem to be important in the elimination of HCV after IFN therapy.

Degree and distribution of variability in the 5' untranslated, E1, E2/NS1 and NS5 regions of the hepatitis C virus (HCV)

Hepatitis C virus (HCV) shows a high degree of variability resulting in many different variants. In this work we described the variability of several subgenomic fragments from the 5' untranslated region (5'-UTR) and E1, E2/NS1 and NS5 regions comparing, for every position, all the sequences published in GenBank v. 88 (July 1995) as well as new sequences obtained in this work. Variability was determined in two ways. First, we analysed the degree and type of substitutions found in these regions. Second, we defined the most variable and conserved segments in each region and compared our prediction with previous studies. Our results confirm that HCV variability changes along the different regions. Although we found four variable domains in the 5'-UTR, this region was the only one to contain conserved domains. Envelope (E1, E2/NS1) and NS5 regions showed high variability throughout; however, we were able to define six and three hypervariable domains, respectively. The degree and distribution of variability established in this work is supported by the high number of sequences and the different types included in the study. Knowledge of how variability is distributed along the different regions of the HCV genome could be of use in the design of new diagnostic and therapeutic strategies against HCV infection.

Risk factors for recurrence of hepatitis C after liver transplantation

Recurrent hepatitis C is a frequent complication after liver transplantation for hepatitis C virus-related cirrhosis, but risk factors related to its development remain ill defined. Twenty-three patients receiving a primary liver graft for hepatitis C virus-related cirrhosis and with an assessable biopsy performed at least 6 months after liver transplantation were studied retrospectively. The end point of this study was to look for risk factors associated with the development of histologic hepatitis C in the graft. Thirty-six major variables were studied, and those reaching significance by univariate analysis were included in a multivariate analysis. Eighteen patients (78%) developed posttransplant hepatitis C. On univariate analysis, six variables showed significant predictive value: increased immunosuppression for treatment of acute rejection; pretransplant hepatocellular carcinoma; cumulative doses of prednisone at 3, 6, and 12 months after transplantation; and mean blood trough levels of cyclosporine in the first 6 months posttransplantation. On multivariate analysis, two variables retained independent statistical significance as predictors of hepatitis C recurrence, namely receipt of antirejection therapy (P = .0087) and lower mean cyclosporine levels in the first 6 months after transplantation (P = .0134). Therefore, recurrence of hepatitis C after liver transplantation seems to be at least partially related to posttransplantation immunosuppressive therapy.

Transmission of hepatitis C virus infection to tree shrews

Although hepatitis C virus (HCV) infection can be reproduced in chimpanzees, these animals are rare and expensive. Tree shrews (tupaias) are small animals, closely related to primates, which adapt easily to a laboratory environment. In this work we have investigated the susceptibility of Tupaia belangeri chinensis to HCV infection. Tupaias caught in the wild in Yunnan (China) were inoculated in China with HCV genotype 1b (study A) and in Spain with a mixture of genotypes 1b, 1a, and 3 (study B). In study B tupaias were divided into three groups: group I was inoculated without previous manipulation, group II received 750 cGy of X-ray whole-body irradiation before inoculation, and group III was used as control. Transient or intermittent viremia occurred in 34.8% (8/23) and anti-HCV in 30.4% (7/23) of tupaias in study A. In study B a transient viremia was detected in 20% (2/10) in group I and in 50% (2/4) in group II. Anti-HCV was found in 1 tupaia from group I and in 3 from group II: Viremia lasted for longer and anti-HCV tended to reach higher titers in animals which received total body irradiation. ALT elevations and nonspecific pathological changes occurred in inoculated tupaias; however, the wild nature of the animals precludes the interpretation of these changes as solely due to HCV infection. In summary our results show that T.b. chinensis are susceptible to HCV and that whole-body irradiation may possibly increase the efficiency of the infection. These animals may serve as an in vivo system for culturing HCV and addressing pathophysiological and therapeutic issues of HCV infection.

Superoxide dismutase in patients with chronic hepatitis C virus infection

It has been reported that hepatitis C virus (HCV) may cause oxidative stress in infected cells. Patients with chronic hepatitis C exhibit an increased production of tumor necrosis factor-alpha (TNF alpha), a cytokine that can produce oxidative stress by stimulating the generation of reactive oxygen species (ROS). Cell defense against ROS includes overexpression of Mn-superoxide dismutase (SOD), an inducible mitochondrial enzyme. To investigate cell defense against oxidative stress in HCV infection, we analyzed Mn-SOD mRNA in liver and in peripheral blood mononuclear cells (PBMC) from patients with chronic hepatitis C. Mn-SOD expression in PBMC was significantly increased in patients with HCV infection. Patients with sustained virological and biochemical response after therapy showed significantly lower Mn-SOD than patients with positive viremia. By contrast, Mn-SOD expression was not enhanced in the liver of patients with chronic hepatitis C. The values of Mn-SOD mRNA did not correlate with TNF alpha mRNA expression, viral load, or liver disease activity. Our results indicate that in HCV infection an induction of Mn-SOD was present in PBMC but absent in the liver, suggesting that this organ could be less protected against oxidative damage. Oxidative stress could participate in the pathogenesis of HCV infection.

Viremia after one month of interferon therapy predicts treatment outcome in patients with chronic hepatitis C

BACKGROUND & AIMS

In chronic hepatitis C, interferon alfa induces sustained remission in less than 30% of treated patients. The aim of this study is to analyze viral status early after initiation interferon therapy as a predictor of treatment outcome.

METHODS

One hundred eighty-one patients with chronic hepatitis C who had been treated with interferon alfa for 12 months (median follow-up, 49 months) were studied. Viremia and aminotransferase levels at the first and third months of therapy as well as 10 pretreatment variables were assessed as potential independent predictors of sustained response to treatment.

RESULTS

Sustained response occurred in 51 patients (28%). At month 1 of treatment, viral persistence accurately predicted nonresponse (predictive value, 95.3; 95% confidence interval, 86.0-98.8; P < 0.0001). Independent predictors of sustained response were undetectable viremia at the first month of therapy (P < 0.001), undetectable viremia at the third month (P < 0.001), younger age (P = 0.006), nonsporadic infection (P = 0.012), and higher pretreatment aspartate aminotransferase levels (P = 0.032). In patients who cleared HCV RNA at month 1 of therapy, the predicted probability of sustained response averaged 70% for those younger than 30 years and diminished by 10% for each decade of age.

CONCLUSIONS

Failure to clear HCV RNA at month 1 of treatment is strongly and independently associated with a very low probability of a sustained response to interferon.

Further insights on the inhibition of HIV type 1 infection in vitro by CD4-modified synthetic peptides containing phenylalanine

Phenylalanine-containing peptides from CD4 were synthesized on the basis of chemical similarity with active CD4(81-92)-benzylated peptides. Systematic replacement of amino acids of these peptides bearing the benzyl group by phenylalanine, afforded several peptides that were able to block the binding of gp120 to CD4 and to inhibit HIV-induced syncytium formation. These experiments showed that substitution of residues 81 and 85 by phenylalanine was the most important for activity. Following optimization of the length of phenylalanine-substituted peptides it was found that FYICFVED and FYICFVEDE were the most active. Their IC50 for the inhibition of syncytium formation was around 1.2-1.6 microM. This activity is at least 30 times higher than that of the parent peptide FYIFFVEDQKEEDD previously reported (Lasarte et al., J Acquir Immune Defic Syndr 1994;7:129-134). Binding competition experiments with two different anti-peptide antisera recognizing the V3 region of gp120 and FYICFVEDE, show that the active peptides bind to V3 or to a sterically near region of V3. None of the active peptides was toxic to cells in vitro. The enhanced activity and simplicity of these new phenylalanine-substituted CD4 peptides might be a good starting point for the development of mimotopes of potential use for the treatment of AIDS.

Production of interleukin-2 in response to synthetic peptides from hepatitis C virus E1 protein in patients with chronic hepatitis C: relationship with the response to interferon treatment

BACKGROUND/AIMS

The role of cellular immunity in the clearance of hepatitis C virus after interferon therapy has not yet been elucidated. Here, we analyzed the T cell response to peptides from hepatitis C virus E1 protein in untreated and interferon-treated patients with chronic hepatitis C virus infection.

METHODS

We used thirty-six 15-mer synthetic peptides from hepatitis C virus E1 protein (genotype 1a) in a sensitive interleukin-2 production assay in two groups of controls (healthy seronegative individuals and patients with liver diseases unrelated to hepatitis C virus), and three groups of patients with chronic hepatitis C: nine patients who cleared the virus after interferon treatment (group 1), nine patients who failed to respond to the therapy (group 2) and nine previously untreated patients (group 3).

RESULTS

None of the controls responded to any of the peptides tested, whereas 8/9 (88%) of patients from group 1 responded positively. In contrast, only 2/9 (22%) of patients from group 2 showed peptide recognition. In group 3, 5/9 patients (55%) displayed positive response against E1 peptides. When E1 peptides from the sequence corresponding to genotype 1b (the commonest in patients who were non-responders to interferon) were tested in nine additional interferon-resistant patients (group 2*) a positive response was detected in only three of them (33%).

CONCLUSIONS

T cell recognition of hepatitis C virus E1 peptides in patients with chronic hepatitis C who exhibit sustained response to interferon therapy is increased as compared with interferon-resistant cases, suggesting that T cell immunity to hepatitis C virus structural proteins may play a role in the clearance of this viral infection.

Epidemiological, clinical and therapeutic associations of hepatitis C types in western European patients

BACKGROUND/AIMS

Different variants of hepatitis C virus might show different susceptibility to interferon alpha treatment, but it is important to understand whether this difference in sensitivity reflects an association with other factors, such as cirrhosis or age.

METHODS

We have used an enzyme-linked immunosorbent hepatitis C virus typing assay based upon the detection of antibody in patient's era to type-specific NS-4 antigens to investigate the effect of hepatitis C virus type in 610 patients with chronic hepatitis C virus infection. The influence of viral types and their interdependency with host factors were separately analyzed to establish which factors executed an independent effect on the probability of sustained response.

RESULTS

There was a marked difference in the distribution of hepatitis C virus types with age: infection with type 3 was more common in younger patients. The distribution of hepatitis C virus type with age is accounted for by differences in risk-factors for infection in different age groups. The frequency of cirrhosis increased markedly with age. Even after standardization for age, center and the presence of cirrhosis, viral type was strongly related to the outcome of infection.

CONCLUSIONS

Our data suggest that enzyme-linked immunosorbent hepatitis C virus typing could assist in patient selection for interferon treatment to improve sustained response rates. Together with measurement of viral load, hepatitis C virus typing may serve to indicate the probability of response in patients with chronic hepatitis C, and to elucidate antiviral mechanisms in the disease. The serotyping assay provides a relatively inexpensive screening method to determine the infecting hepatitis C virus type, which could facilitate therapeutic decisions and strategies in patients with chronic hepatitis C.

Anticardiolipin antibodies in chronic hepatitis C: implication of hepatitis C virus as the cause of the antiphospholipid syndrome

Antiphospholipid antibodies are a type of autoantibodies that have been implicated in the occurrence of thrombocytopenia and thrombotic events and have been described in autoimmune disorders and diverse viral diseases. In this study anticardiolipin antibodies (immunoglobulin G [IgG] isotype) were determined in serum from 100 patients with chronic hepatitis C and 52 healthy controls. In addition, hepatitis C virus (HCV) markers (anti-HCV and HCV RNA) were investigated in 73 patients with thrombotic disorders and no clinical evidence of liver disease; of these patients 37 cases tested negatively for anticardiolipin antibodies and 36 positively. Anticardiolipin test was positive more frequently (22%) in the group of patients with chronic hepatitis C than in healthy controls (1.9%; P < .001). Using conditional logistic-regression analysis we found that in hepatitis C patients the presence of thrombocytopenia, portal hypertension and the existence of prior thrombotic episodes were significantly related to positivity for anticardiolipin antibodies (P < .05 in all cases). In patients with no evidence of liver disease and a history of thrombotic events, hepatitis C markers were absent in all cases who tested negatively for anticardiolipin antibodies (n = 37), but were present in 16.7% of those positive for anticardiolipin (n = 36) (P = .01). In conclusion, anticardiolipin antibodies are frequently found in patients with chronic hepatitis C and in these patients they may be implicated in the occurrence of thrombosis and in the development of thrombocytopenia. Occult HCV infection is present in a significant proportion of patients with thrombotic disorders and positive for anticardiolipin (the antiphospholipid syndrome).

Tumor necrosis factor alpha gene expression and the response to interferon in chronic hepatitis C

Tumor necrosis factor alpha (TNF-alpha) is a cytokine with pleiotropic properties that is induced in a variety of pathological situations including viral infections. In this work, we analyzed the expression of TNF-alpha gene in patients with chronic hepatitis C. Serum TNF-alpha levels were found to be elevated in all chronic hepatitis C patients including those cases presenting sustained biochemical remission of the disease after interferon therapy. Untreated patients with chronic hepatitis C showed increased TNF-alpha messenger RNA (mRNA) levels in the liver and mononuclear cells as compared with healthy controls. After completion of treatment with interferon, patients experiencing sustained complete response showed values of TNF-alpha mRNA, both in the liver and in peripheral mononuclear cells, within the normal range, significantly lower than patients who did not respond to interferon and than those with complete response who relapsed after interferon withdrawal. Pretreatment values of TNF-alpha mRNA were lower in long-term responders to interferon than in cases who failed to respond to the treatment. Values of TNF-alpha mRNA in the liver or in mononuclear cells were higher in specimens with positive hepatitis C virus (HCV) RNA than in those samples where the virus was undetectable. Neither the intensity of the liver damage nor the amount of HCV RNA in serum or in cells showed correlation with the levels of TNF-alpha transcripts in peripheral mononuclear cells but it was found that high TNF-alpha values were associated with genotype 1b. In conclusion, there is an enhanced expression of TNF-alpha in HCV infection. High levels of this cytokine may play a role in the resistance to interferon therapy.

The GCGGAA gene-regulatory motif of herpes simplex virus type-1 is also found in hepatitis C virus

We have analyzed the sequence of the 5'-untranslated region of hepatitis C virus from 24 patients with chronic hepatitis C and we found a conserved six-nucleotide motif previously described as a modulator of gene expression.

Prediction of sustained remission of chronic hepatitis C after a 12-month course of alfa interferon

alpha-Interferon therapy normalizes aminotransferase levels in approximately 50% of the patients with chronic hepatitis C, but post-therapy relapses are common and predictive factors of sustained response remain largely unknown. We retrospectively assessed several parameters as predictors of sustained remission after a 12-month course of lymphoblastoid alpha-interferon: the Knodell histological activity index, serum levels of procollagen type III peptide, serum HCV-RNA, anti-alpha-interferon antibodies, and anti-HCV antibodies (C-100-3), all at month 12. Thirty-seven patients were studied. Fourteen patients were non-responders (38%), 15 patients experienced a sustained response (40.5%) and eight patients responded similarly but relapsed after alpha-interferon withdrawal (21.5%). A decrease in the histological activity index above 5, normalization of procollagen type III peptide levels (< 12 ng/ml) and the absence of viremia after treatment were all significantly associated with a sustained response (p = 0.008, p = 0.007 and p = 0.037, respectively). Anti-interferon antibodies were detected in only one non-responder patient. Anti-C-100-3 antibodies became undetectable at month 12 in 5 of the 15 sustained responders. The best prediction of sustained response was obtained from the three variables independent of multivariate analysis according to the following equation: F = 0.872 + 0.067 x K (decrease of histological index) -0.052 x P (procollagen type III peptide levels at month 12) -0.28 x R (HCV-RNA at month 12; R = 2 when present and R = 1 when absent). A score higher than 0 predicted sustained remission with a 100% sensitivity and specificity in this series of patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Defective proliferation and regulatory function of CD4+ T cells bearing Leu-8 homing receptor in primary biliary cirrhosis. Phorbol myristate acetate enhances T-cell function

The majority of circulating CD4+ T cells express the Leu-8 peripheral lymph node homing receptor, and these cells have previously been shown to have suppressor-inducer and suppressor function. In the present study, it was found that CD4+, Leu-8+ T cells from patients with primary biliary cirrhosis (PBC) have a significantly (P < 0.01) lower proliferative response when stimulated with phytohemagglutinin (PHA), concanavalin A (Con A), or pokeweed mitogen (PWM) compared to normal controls. The proliferative response of CD4+, Leu-8- T cells was similar in patients and controls. However, the proliferative responses of CD4+, Leu-8+ from patients with PBC was normal when cells were stimulated with PHA, Con A, anti-CD3 monoclonal antibody, or ionomycin in combination with phorbol myristate acetate (PMA). CD4+ T cells from patients with PBC mediated normal helper function for PWM-stimulated immunoglobulin synthesis at high T/B ratios and their regulatory function was similar to that of normal CD4+ T cells that had been irradiated to inactivate their suppressor activity. When CD4+ T cells from patients with PBC were precultured with the combination of Con A and PMA, they mediated potent inhibitory activity similar to that of normal CD4+ T cells. Thus, CD4+, Leu-8+ T cells from patients with PBC have a defect of proliferation and suppressor function that is reversed by coculture with PMA. This finding suggests that impairment of a PMA-inducible lymphocyte activation pathway contributes to abnormal lymphocyte function in PBC.

High prevalence of HHV-6 DNA in peripheral blood mononuclear cells of healthy individuals detected by nested-PCR

The aim of the study was the evaluation of human herpesvirus-6 (HHV-6) infection rate and semiquantification of viremia in healthy people. Healthy blood donors were studied. Human herpesvirus-6 IgG and IgM antibody titers were measured by indirect immunofluorescence assay. Human herpesvirus-6 DNA amplification (nested-PCR) was performed in peripheral blood mononuclear cells (PBMC) and in serum. Seventeen of 50 (34 percent) individuals were positive for IgG anti-HHV-6 and the titers ranged from 1:40 to 1:160. None of 30 individuals was positive for IgM anti-HHV-6, suggesting no recent infection nor reactivation. Human herpesvirus-6 DNA was detected by nested-PCR amplification in peripheral blood mononuclear cells but not in sera. When 1 microgram DNA was amplified, HHV-6 DNA was detected in 8 of 20 individual (40%), but in 18 of 20 (90%) when 5 micrograms DNA were amplified. It is concluded that HHV-6 is present in a high proportion of the healthy population but in minimal amounts, and although it can be detected in 1.4 x 10(5) PBMC, 7 x 10(5) cells are necessary to detect most cases. No reactivation was observed in healthy people.

Reduced numbers of CD8+ T cells and B cell-expression of Leu-8 antigen in peripheral blood of patients with primary biliary cirrhosis

The presence of Leu-8 antigen, the human homologue of the murine MEL-14 peripheral lymph node homing receptor, defines subsets of peripheral blood mononuclear cells (PBMC) with different functions. Since it has been suggested that abnormal function of Leu-8 subsets may contribute to the immunopathogenesis of primary biliary cirrhosis (PBC), this study was undertaken to define whether abnormal expression of the Leu-8 antigen occurs in this disease. We studied 25 PBC patients, 12 with other chronic liver diseases, and 21 normal controls. PBMC were tested by direct immunofluorescence using monoclonal antibodies and flow cytometry. In PBC the proportion of PBMC that were CD4+ was normal; in contrast, the proportion that were CD8+ was decreased (p < 0.01). A negative correlation was found between absolute numbers of CD8+ T cells and total serum bilirubin levels (r = -0.50, p < 0.05). The distribution of Leu-8 antigen on T cells was normal; however, the proportion of PBMC that were B cells was increased (p < 0.01) and the fraction of these that were Leu-8 negative was also increased (p < 0.01). The expression of antigens of activation on B cells was similar to that for normal controls. These findings suggest that in peripheral blood of PBC patients reduced numbers of T cells may occur due to a selective intrahepatic sequestration of CD8+ T cells, and that the decreased expression of Leu-8 antigen by B cells may be associated with their participation in autoimmune processes.

CD4-modified synthetic peptides containing phenylalanine inhibit HIV-1 infection in vitro

Phenylalanine-containing peptides from CD4 were synthesized based on chemical similarity with active CD4(81-92)-benzylated peptides. The synthetic peptide FYIFFVEDQKEEDD blocked the binding of gp120 to CD4 and inhibited 50% human immunodeficiency virus (HIV)-induced syncytia formation at a concentration (IC50) of approximately 40-50 microM and HIV p17 expression with an IC50 of approximately 67 microM. The peptide is not toxic to cells in vitro. Moreover, acute toxicity studies carried out in Swiss mice showed the peptide to be nontoxic at a dose of 2,000 mg/kg. This phenylalanine-substituted CD4 peptide may prove to be useful in the treatment of AIDS.

Prediction of the response of chronic hepatitis C to interferon alfa: a statistical analysis of pretreatment variables

Pretreatment variables that could predict the response of chronic hepatitis C to interferon alfa treatment have not been fully assessed. Eighteen baseline variables were evaluated in a series of 100 consecutive patients treated with a 12 month course of interferon alfa. For the purposes of this study, response was defined as the return to normal of aminotransferase activities before the third month of treatment. Seventy per cent of the patients responded to treatment. Six variables were associated with an increased likelihood of response assessed by univariate analysis. With stepwise multiple regression analysis assessment, however, only three variables remained independently predictive of response: low gamma glutamyltransferase (gamma GT) activities (p < 0.001), absence of obesity (p = 0.005), and absence of cirrhosis (p = 0.01). The response rate in patients with gamma GT activities < 0.66 mu kat/l (n = 55) was 78% and 60% in patients with values > 0.66 mu kat/l (n = 45) (p = 0.048). Response was attained in 75% of non-obese patients (n = 80), compared with only 50% of obese patients (n = 20) (p = 0.03). Finally, 80% of patients without cirrhosis (n = 76) responded, while among those with cirrhosis (n = 24) the response rate was only 37% (p < 0.001). All 23 patients without cirrhosis, <40 years old, and with gamma GT activities <0.66 mu kat/l responded to treatment, while only 28.5% of 14 patients with cirrhosis, >40 years old, and with gamma GT activities >0.66 mu kat/l responded to interferon alfa (p<0.001). Those findings may be useful when evaluating interferon alfa trials and it is suggested that this treatment should be applied early in the course of chronic hepatitis C.

Hepatic and extrahepatic HCV RNA strands in chronic hepatitis C: different patterns of response to interferon treatment

We investigated the presence of positive (genomic) and negative (replicative intermediate) hepatitis C virus RNA strands in liver, peripheral mononuclear cells and serum from patients with chronic hepatitis C using a selective and semiquantitative polymerase chain reaction procedure. Negative and positive hepatitis C virus RNA strands were present in liver, serum and lymphoid cells in all untreated patients and in all those who did not respond to interferon therapy. In the latter group of patients, the titers of RNA strands in the liver and peripheral mononuclear cells at the end of the treatment were similar to those encountered in untreated patients, but the serum titers were about 100 times lower than pretreatment values. In patients who responded to interferon with normalization of serum aminotransferase levels (n = 10), the rate of detection and the titer of the two viral strands in liver, serum and mononuclear cells were markedly decreased at the end of the therapy. In the six responders who did not relapse after interferon withdrawal, both hepatitis C virus RNA strands were absent from the liver, serum and lymphoid cells. By contrast, the positive RNA strand was present in liver cells, mononuclear cells or both at the end of therapy in all patients who experienced posttherapy relapse. In conclusion, our results indicate that interferon can clear hepatitis C virus from hepatic and extrahepatic sites only in responder patients. Disappearance of genomic hepatitis C virus RNA from the liver and from mononuclear cells may predict complete response without posttherapy relapse.

Ribavirin in the treatment of chronic hepatitis C unresponsive to alfa interferon

For the 30-50% of patients with chronic hepatitis C who do not respond to alpha-interferon therapy there is no alternative treatment. Some previously untreated patients have shown a biochemical response to ribavirin, but the antiviral effects of this substance on alpha-interferon-resistant cases is largely unknown. Twelve patients with chronic hepatitis C who had not responded to a 6-12 month course of alpha-interferon were included in this study. Oral ribavirin was administered at a dose of 16 mg/kg per day for 6 or 9 months. Aminotransferase levels had not significantly changed during interferon therapy but decreased significantly during ribavirin treatment (mean alanine aminotransferase at baseline, 102 +/- 18 IU/l vs. 55 +/- 14 IU/l at 6 months; P = 0.0001). Aminotransferase levels became normal in 6 cases (50%), significantly decreased in 3 patients (25%), and did not significantly change in the remaining 3 cases (25%). All patients with normalized aminotransferase values relapsed after ribavirin was discontinued and aminotransferase activity returned to pretreatment levels. Before therapy serum hepatitis C virus RNA was detected by polymerase chain reaction in 10 cases. None of them had cleared viral RNA when tested following 3, 6 and 9 months of ribavirin therapy. Side-effects were mild and reversible. In conclusion, about half of the patients with chronic hepatitis C who are unresponsive to alpha-interferon show a clear-cut biochemical response after 6-9 months of ribavirin administration. However, ribavirin does not clear circulating hepatitis C virus RNA and relapses occur after withdrawal.(ABSTRACT TRUNCATED AT 250 WORDS)

N-acetyl cysteine enhances the response to interferon-alpha in chronic hepatitis C: a pilot study

Hepatitis C virus (HCV) is an RNA virus that replicates in both the liver and lymphoid cells. Interferon-alpha (IFN-alpha) is a useful treatment of chronic hepatitis C (CHC) although resistance to this drug occurs frequently. The mechanisms underlying resistance to IFN remain unknown. In this work, we have measured the levels of glutathione in plasma and peripheral lymphoid cells from 15 healthy controls and 24 CHC patients, 10 of whom were without treatment and 14 showed high serum alanine aminotransferase (ALT) values despite therapy with lymphoblastoid IFN for more than 4 months. In all patients, glutathione levels in plasma and in mononuclear cells were depressed in comparison to controls. In IFN-unresponsive patients, the addition of 600 mg tid of oral N-acetyl cysteine (NAC), a glutathione precursor, resulted in a steady decrease of ALT values in all patients, with complete normalization in 41% of cases after 5-6 months of combined therapy. Administration of NAC alone for 1 month was without effect in the 10 patients that were not receiving IFN. Supplementation of IFN with NAC induced a near normalization of intralymphocytic glutathione, but plasma levels were only moderately increased. HCV replication was markedly inhibited in lymphocytes and viremia was cleared in one of the 8 patients tested. In conclusion, NAC enhances the response to IFN in CHC. Controlled studies are needed to ascertain whether antioxidant therapy might act in synergy with IFN in chronic viral hepatitis.

Histological outcome of chronic hepatitis C treated with a 12-month course of lymphoblastoid alfa interferon

To assess the effect of long-term alfa interferon therapy (12 months) on liver histology of chronic hepatitis C, we studied 61 treated patients, and compared their outcome with 28 untreated cases followed as controls. A liver biopsy was taken from all patients, before (month 0) and after the completion of the treatment or the control period (month 12). A third liver specimen taken at month 24 was available in 29 treated cases. Liver biopsies were blindly graded following Knodell's method. In 33 out of the 61 treated patients (54.1%), aminotransferase levels became normal shortly after starting therapy and remained within normal values until the end of treatment (sustained response). Nine (27%) sustained responders relapsed after interferon discontinuation, while the remaining 24 (73%) continued with normal aminotransferase values during follow-up (16.8 +/- 9.9 months). All histological parameters, except fibrosis, improved significantly after 12 months of therapy (periportal necrosis, month 0: 2.7 +/- 1.0, month 12: 1.6 +/- 1.1, p < 0.0001; lobular damage, month 0: 2.5 +/- 1.1, month 12: 1.4 +/- 0.9, p < 0.0001; portal inflammation, month 0: 3.6 +/- 0.5, month 12: 3.0 +/- 0.9, p < 0.0001). Histological improvement was especially marked in patients who did not relapse, although those who relapsed and partial responders also improved. Overall histological diagnoses improved in most patients. A sustained response to interferon was predicted by high periportal and lobular scores, and by a low fibrosis score on the pretreatment liver biopsy. At 24 months, histological improvement persisted in patients without posttreatment relapse, while liver inflammation had returned to pretreatment levels in the remaining cases.

Detection of anti-hepatitis C virus antibodies by ELISA using synthetic peptides

A novel ELISA assay for the detection of anti-hepatitis C virus antibodies in the sera of infected individuals is described. This assay is based on a mixture of three 15-amino acid synthetic peptides encompassing regions of core and NS4 proteins of hepatitis C virus. Comparison with other available ELISA assays based on recombinant polypeptides shows that, short synthetic peptides have the advantage over some larger recombinant peptides by giving higher specificity without loss of sensitivity.

Hepatitis B virus occult infection in subjects with persistent isolated anti-HBc reactivity

The aim of this study was to investigate the presence of hepatitis B virus occult infection in asymptomatic subjects with persistent anti-HBc reactivity but no other hepatitis B virus serological markers, including HBsAg, anti-HBs, IgM anti-HBc and HBV-DNA. For this purpose we used both polymerase chain reaction assays in sera and immunohistochemistry for HBsAg and HBcAg in liver biopsy specimens. Twenty-four cases were studied: 15 were drug abusers or homosexuals (eight with normal alanine aminotransferase levels) and nine were heterosexuals with raised alanine aminotransferase levels (> 45 U/l) but with no history of blood transfusion or ethanol intake (< 80 g daily). In all but five cases, liver biopsy was performed in subjects with persistent elevated alanine aminotransferase levels. In 10 out of 24 cases (41.66%) hepatitis B virus infection was demonstrated by polymerase chain reaction or immunohistochemistry, and when results from both procedures were available (n = 11) hepatitis B virus infection was detected in 63.63% of the subjects. The only clinical feature associated with HBV infection was the presence of persistent elevated alanine aminotransferase levels (p < 0.05). In conclusion, persistent isolated anti-HBc reactivity may be a relatively common serologic pattern for hepatitis B virus occult infection, at least in patients with chronic liver disease.

Randomised trial of lymphoblastoid alpha-interferon in chronic hepatitis C. Effects on inflammation, fibrogenesis and viremia

Seventy-two patients with chronic hepatitis C were included in a randomised trial of lymphoblastoid interferon versus no treatment. Thirty-six patients entered each group. Interferon was given in a step-down schedule for 12 months. Aminotransferase activities became normal during treatment in 30 of 36 (83.3%) treated patients, but in only 1 out of 36 (2.7%) non-treated cases (p < 0.001). However, a reactivation of the disease during the interferon course was observed in 12 patients after a mean of 5.58 +/- 1.55 months of therapy, and a post-treatment relapse was observed in 5 additional cases. The remaining 13 patients (36%) had sustained normalization of the aminotransferase levels for 15.27 +/- 10.34 months (range 3-30) after discontinuation of interferon, thus representing a long-term sustained remission of the disease. Knodell's histological activity index decreased in all treatment patients, except for 3 non-responders (91.5%), but in only 9 of 36 non-treated cases (25%) (p < 0.001). Procollagen type III peptide levels normalized in most cases (83%) with a sustained response. A significant decrease in the detection of hepatitis C virus RNA was observed in patients with a sustained response (p < 0.05). Anti-interferon antibodies were only detected in one non-responder. Thus, interferon diminishes inflammatory and fibrogenic activity in the majority of patients with chronic hepatitis C and abolishes viremia in most of the patients with a sustained response.

Lymphoblastoid alpha-interferon for chronic hepatitis C: a randomized controlled study

Forty patients with chronic hepatitis C (CHC) were included in an open randomized controlled trial of lymphoblastoid alpha-interferon (L-IFN) versus no treatment. Twenty patients entered each group, and features of therapy and control cases were similar. L-IFN was given in low doses (1.5-4.5 megaunits) for 1 yr. In 16 of 20 patients treated with L-IFN (80%), but in only one of 20 nontreated cases (0.5%; p < 0.001), amino-transferase activities became normal. In four patients there was a reactivation of the disease during treatment after 4, 5, 6, and 8 months with normal aminotransferase levels. A posttherapy reactivation of hepatitis was observed in four additional cases after 1, 1, 1, and 3 months of follow-up. The other eight patients (40%) continued with normal aminotransferase levels for 1.52 +/- 0.74 (range, 1-2.1) yr after IFN doses were discontinued. In all treated patients except two nonresponders, but in only one of 20 nontreated cases (p < 0.001), Knodell's histological activity index decreased. Procollagen type III aminoterminal peptide levels did not change significantly in nontreated and nonresponder patients, diminished slightly in patients with a transient response, and normalized in cases with a long-standing response, suggesting that this serum test may be a reliable marker for monitoring response to IFN therapy in patients with CHC. Finally, L-IFN treatment induced significant increments in CD4/CD8 index, phytohemagglutinin-induced blastogenesis, and natural killer activity. This study shows that L-IFN diminish inflammatory and fibrogenic activity in most patients with CHC. In 40% of patients treated in this trial, a long-standing remission of the disease was observed.

The stilbene disulfonic acid DIDS stimulates the production of TNF-alpha in human lymphocytes

Exposure of human peripheral blood mononuclear cells (PBMC) to the stilbene derivative DIDS (4,4'-diisothiocyanatostilbene-2,2'-disulfonic acid) (60 microM and above) significantly increased the release of tumor necrosis factor-alpha (TNF-alpha), as determined by TNF-alpha activity in the incubation media. When the TNF-alpha message was analyzed in PBMC by a reverse transcription/polymerase chain reaction (RT/PCR)-based procedure, it was found that incubation with DIDS (60 microM) was followed by a time-dependent accumulation of TNF-alpha mRNA. Measurements of intracellular pH showed that the presence of increasing concentrations of DIDS resulted in a progressive intracellular alkalinization of PBMC. It is suggested that the known DIDS effect of inhibiting transmembrane anion exchange, i.e., chloride/bicarbonate exchange, might play a role in the stimulation of TNF-alpha production by PBMC exposed to DIDS.

Replication of hepatitis C virus in peripheral blood mononuclear cells. Effect of alpha-interferon therapy

Hepatitis C virus (HCV) is a positive-stranded RNA virus which replicates through a negative-stranded RNA intermediate. Using a PCR procedure to detect positive and negative strands, we investigated the existence of HCV replication in lymphoid cells. Both positive and negative strands were found in the peripheral blood mononuclear cells (PBMC) of all patients (n = 10) with untreated chronic hepatitis C. No HCV sequences were detected in PBMC in any of the 8 healthy controls. Fifteen patients with chronic hepatitis C were studied at the end of a 12-month course of alpha-interferon therapy. The positive strand was detected in PBMC in all 9 non-responder patients, and the negative strand in 7. In contrast, in PBMC from responder patients (n = 6) the positive strand was found in 4 and the negative strand in only 2 cases. These results demonstrate that HCV can infect PBMC and replicate in these cells and that interferon seems to exert an inhibitory effect on this process. Persistence of HCV-RNA in PBMC may help explain disease relapse after successful interferon therapy.

[Monocytic dysfunction by opioid peptides in patients with major depression]

BACKGROUND

Patients with depression present immunodepression and it has been proposed that, in these patients, endogenous opioid peptides may be mediators between the dysfunction of the central nervous system and immune alterations.

METHODS

The function and the surface markers of monocytes were studied in 15 patients with major unipolar depression and in 24 healthy controls by biological trials of phagocytosis of Candida albicans and latex particles and immunofluorescence with monoclonal antibodies.

RESULTS

Most of the patients studied (86%) presented monocytic dysfunction characterized by diminished phagocytic activity and a decrease in the expression of intermediate filaments of vimentin of the cytoskeleton and membrane molecules (CR1, receptor for the Fc fraction of the IgG and HLA DR antigens). Incubation of the patients monocytes with naloxone led to the disappearance of monocytic alterations in most of the patients.

CONCLUSIONS

Patients with major unipolar depression present a high opioid tone which has consequences in the function of the immune system.

Detection of hepatitis C virus antibodies with new recombinant antigens: assessment in chronic liver diseases

A new serological assay to detect antibodies against hepatitis C, based on a recombinant protein (BHC10) which incorporates structural and non-structural viral antigens, was tested in 67 healthy subjects and 409 patients with various forms of liver disease. Results were compared with the current assay based on the recombinant non-structural viral antigen c100 and with the recently introduced second-generation assay, Ortho2. None of the healthy subjects was positive by any of the assays. In patients with chronic non-A, non-B hepatitis the prevalence of anti-BHC10 was 96.8%, higher than anti-c100 (83.3%, p less than 0.001) and similar to Ortho2 (94.3%). False-positive results were less frequently found when BHC10 was used. These findings show that assays incorporating structural and non-structural antigens provide higher sensitivity to detect hepatitis C virus infection and they define an almost exclusive role of hepatitis C virus in the genesis of chronic non-A, non-B hepatitis.

[Detection of hepatitis B virus DNA in serum by gene amplification in patients with chronic hepatitis B and in patients chronic hepatitis C]

BACKGROUND

The polymerase chain reaction (PCR) constitutes important methodological progress for detecting the presence of viral nucleic acids when these are found in small quantities in serum or tissues. The aim of this study was the use of PCR to detect DNA of the hepatitis B virus (HBV) in patients with chronic HBsAg positive hepatitis (HC-B) and in patients with chronic non A non B hepatitis with antibodies against the virus of hepatitis C (anti-HCV) positive (HC-C).

METHODS

The DNA of the HBV was determined with PCR in the serum of 40 patients with HC-B and in 15 with HC-C. Moreover, the presence of anti-HCV was studied in the patients with HC-B.

RESULTS

The presence of DNA of the HBV was detected by PCR in 69% of the HC-B patients presenting HBeAg positive and DNA of the HBV negative by simple hybridization as well as in 50% of the patients with HBeAg negative, anti-HBe positive and DNA of HBV negative by simple hybridization. In addition, DNA of HBV was detected by PCR in 27% (4/15) of the subjects with HC-C, three of whom had anti-HBc antibodies. On the other hand, 20% of the patients with HC-B had anti-HCV. Anti-HCV positivity was associated to a greater hypertransaminasemia in patients with HC-B in a non replicative phase.

CONCLUSIONS

PCR is a sensitive method for detecting viral replication. Its use permits the detection of low DNA concentrations of the HBV in a low but appreciable percentage of chronic negative HBsAg hepatitis. Coinfection by the B and C viruses of hepatitis is not exceptional and explains hypertransaminasemia in some HC-B in a non replicative phase.

Induction of antibodies against a peptide hapten does not require covalent linkage between the hapten and a class II presentable T helper peptide

Following immunization with a complex antigen, a B cell internalizes this antigen through an interaction between its surface immunoglobulins and an epitope of the antigen. Enzymatic processing of the antigen frees one or more short peptide determinants (TD) which bind to class II molecules of the B cell. If the complex TD-MHC II is recognized by the receptor of a T helper cell, T cell help is provided leading to the expansion of an antibody-producing B cell clone specific for the epitope. We present experimental evidence proving that the induction of anti-peptide hapten antibodies does not require covalent linkage between the peptide hapten and the peptide behaving as TD. Indeed, high anti-peptide hapten antibody titers are induced if an emulsion of TD and hapten are injected in the same immunization site. This result suggests a way to manipulate antibody production with useful applications to research and therapy.

[Type 6 human herpes virus and chronic asthenic syndrome]

Chronic asthenia syndrome has been associated with Epstein-Barr virus (EBV). To investigate the possible role in this syndrome of human herpesvirus type 6 (HHV-6), a new herpesvirus discovered in 1986, we performed a serological study of 44 patients diagnosed of chronic asthenia syndrome and 50 controls. Fifty healthy controls (34%) and 44 patients (54.5%) had positive serological tests for HHV-6. This difference was significant (p less than 0.05). The rate of positive serological studies for CMV and EBV was higher in healthy controls (n = 50) than in patients (n = 37) (96% vs 67.7% for CMV [p less than 0.001] and 92% vs 78.4% for EBV [non significant difference]). We conclude that HHV-6 may play a role in the pathogenesis of chronic asthenia syndrome. In our group of patients there were no significant differences in the presence of anti EBV capsid antibodies.

Monocyte disorder causing cellular immunodeficiency: a family study

We report a familial type of monocyte dysfunction not recognized previously. This disorder was observed in a young adult man with a long clinical history of recurrent, self-limited episodes of cryptogenic fever accompanied by digestive and respiratory symptoms and repeated oral and skin infections. Lectin-induced lymphocyte transformation was reduced and skin tests revealed anergy to tuberculin and candidin. Monocytes from this patient exhibited markedly diminished expression of cytoskeletal vimentin intermediate filaments, HLA-DR antigens and immunological receptors for IgG Fc and C3b. These abnormal monocytes demonstrated impaired phagocytosis and reduced accessory cell function on PHA-mediated lymphocyte activation. Release of soluble lymphocyte-activating factors by these cells was found to be defective. Lymphocytes from the patient responded appropriately to lectin in the presence of normal monocytes. Two family members of the proband presented similar monocyte defects although they only manifested minor clinical symptoms. This syndrome underlines the interest of testing monocyte markers and function in subjects with clinical manifestations of immunodeficiency.

[Treatment of chronic hepatitis B with lymphoblastoid alpha interferon]

Thirty-five patients with active chronic hepatitis B (ACH-B) were evaluated. They were in stable replicative phase (HBeAg +; DNA polymerase and ALT stable in two determinations at least one month apart) and had not been infected by delta virus or HIV-1. Thirty-four patients were heterosexual and no patient was a drug abuser except one. The 23 initial cases were followed up for 15 months without therapy. The subsequent 12 cases were treated with maximal doses of 2.5 megaunits/m2 of lymphoblastoid alpha interferon (IFN-L) daily for two weeks and three times a week during 10 more weeks. While in the controls only two cases (8.69%) lost the DNA-polymerase activity and HBeAg, 5 treated patients (41.66%; p less than 0.05) developed seroconversion to nonreplicative phase. No patient from the control series lost the HBsAg; however, this happened in 2 treated patients (16.66%). These results show that IFN-L is effective in heterosexual patients with ACH-B in replicative phase without delta virus or HIV-I co-infection.

Defective immunoregulation in primary biliary cirrhosis: CD4+, Leu-8+ T cells have abnormal activation and suppressor function in vitro

To determine whether abnormalities of lymphocyte function in primary biliary cirrhosis are due to altered function of immunoregulatory T cell subpopulations, phenotypic and functional characteristics of CD4+ T cells were examined. The proportion of CD4+ T cells expressing the Leu-8 and CD45R antigens was normal in patients with primary biliary cirrhosis. The capacity of CD4+, Leu-8- T cells to provide helper function for pokeweed mitogen-stimulated immunoglobulin synthesis by B cells in vitro was similar in patients and controls. However, in contrast to normal individuals and patients with other liver diseases, CD4+, Leu-8+ T cells from six of 10 patients with primary biliary cirrhosis did not suppress, but enhanced immunoglobulin synthesis. Whereas treatment of CD4+ T cells from normal individuals with anti-Leu-8 monoclonal antibody enhanced their suppressor function, similar treatment of CD4+ T cells from patients with primary biliary cirrhosis did not increase their suppressor function. To determine whether the abnormal regulatory function of CD4+, Leu-8+ T cells was due to a defect of cell activation, the proliferative response of CD4+ T cell subpopulations to mitogenic stimulation was examined. The proliferative responses of CD4+, Leu-8- T cells from patients with primary biliary cirrhosis and controls were similar, but the proliferative responses of CD4+, Leu-8+ T cells from patients with primary biliary cirrhosis were lower than those of control cells.(ABSTRACT TRUNCATED AT 250 WORDS)

A pilot study of thymus extract in chronic non-A, non-B hepatitis

In previous studies it has been suggested that activation of cellular immunity may have a role in controlling the activity of chronic non-A, non-B liver disease. We conducted a pilot study of therapy with a bovine thymus extract for 6 weeks in 15 consecutive patients with chronic non-A, non-B hepatitis, most of them sporadic cases. Treatment induced immunomodulation, and in five patients a significant but transient diminution in aminotransferase levels was observed associated with increments in several parameters of cellular immunity. This suggests that a longer administration of this or other related compounds, or treatment with a more potent immunomodulating agent, might be effective in these patients.