Hepatitis C virus (HCV) infection causes chronic hepatitis, which is often associated with suppressed anti-HCV immune responses. We have recently reported accumulation of myeloid-derived suppressor cells (MDSCs) and suppressed immunity in cancer patients.

The main aim of this study was to determine whether chronic HCV patients harbor high of MDSCs in general and in nonresponders to IFN-based therapy in particular as well as to analyze the immune suppressive molecules.

Peripheral blood samples withdrawn from 154 patients with chronic HCV infection and were categorized into responders and nonresponders based on viral titer upon IFN-α treatment.

The relative and absolute numbers of MDSCs defined as Lin-/HLA-DR-/CD33+/CD11b+ increased in all HCV patients, where they were higher in nonresponders than in responders. Additionally, the levels of MDSCs after 4-6 months of treatment in responders were lower than during the course of treatment. The responders also showed higher levels of IL-2 coincided with increased numbers of dendritic cells (DCs), CD4+ and CD8+ T cells. The levels of total NOS and IDO were also higher in nonresponders as compared to responders and healthy controls, while the expression levels of CD3ζ was lower in responders as compared to nonresponders and healthy volunteers.

Chronic HCV patients harbor high numbers of MDSCs, which are higher in nonresponders than in responders. The higher numbers of MDSCs associated with increases in the suppressing factors.

It has been suggested that soluble CD30 (sCD30) serum levels in chronic hepatitis C are correlated with the activity of the disease and with the outcome of interferon (IFN) treatment. In this study, sCD30 serum levels in 25 patients with chronic hepatitis C, before and after treatment with IFN-2alpha, were measured. A total of 20 healthy subjects were used as controls. High sCD30 levels in serum were found in 36% of patients and in 5% of controls. In patients with sCD30 levels above or within the normal range, no significant differences in age, gender, serum transaminases and histology activity index were found. In relation to IFN treatment, only responder patients had serum sCD30 higher than controls, although the difference between responders and non-responders was not significant. No changes from baseline values were observed after treatment. Although high, sCD30 serum levels in chronic hepatitis C are not correlated with the disease activity, are not affected by IFN treatment and are not predictors of response to IFN treatment.

The viral genotype and serum viral level influence the response to interferon (IFN) treatment in patients with chronic hepatitis C virus (HCV) viremia. The aim of this study was to investigate a possible relationship between early virological response and helper T (Th) cell cytokine expansion by 4 weeks of ribavirin (RIB) alone followed by IFN and RIB combined in patients with genotype 1b and a high HCV RNA level, patients reported not to respond well to IFN treatment. Eighty-one patients with genotype 1b and a high HCV RNA level, over 100 international unit per milliliter (KIU/mL) (by Amplicor HCV Monitor), were assigned to two groups: Group A (N = 40) with a 4-week RIB administration followed by a 24-week combination treatment, and Group B (N = 41) with a 24-week combination treatment only. Blood was obtained from each patient on the following schedule: at Baseline (4 weeks before day 0), on day 0 (initiation day of the RIB and IFN combination treatment), weeks 4 (4 weeks after the start of the combination treatment), and at the end of the combination treatment. Flow cytometry was used to investigate sequential changes of IFN-gamma producing (Th1) and interleukin-4 producing (Th2) cells from whole blood samples after stimulation with PMA and ionomycin. Serum HCV RNA clearances were 32.5% at week 4, 43.2% at week 8, 85.7% at the end of the combination treatment, and 22.9% within the 24-week follow-up in Group A; and 17.1%, 27.0%, 66.7% and 19.4% in Group B, respectively. The mean Th1/Th2 ratio significantly increased from 15.9 at baseline to 17.6 at day 0 with a decrease of Th2 cells, and then significantly decreased from 17.6 at day 0 to 15.5 at week 4 in Group A, while there was no significant change in Group B between baseline and day 0. In Group A, 13 patients with HCV RNA clearance within 4 weeks had a significantly increased Th1/Th2 ratio, from 14.0 at baseline to 22.1 at day 0, and then a significantly decreased ratio, from 22.1 at day 0 to 15.0 at week 4, while the others had no significant change in the ratio. RIB administration preceding combined treatment of RIB with IFN was more effective in Th2 cell expansion than the usual combined treatment of IFN with RIB and led to a relatively early virological clearance in chronic hepatitis C patients with genotype 1b and a high HCV RNA level.

We studied the relationship between immunological markers such as CD4+ proliferation, cytokines profile and lymphocyte activation markers in patients with chronic hepatitis C, having different responses to interferon (IFN) and ribavirin (RBV) treatment. A prospective study of 20 patients was conducted, six had received IFN-alpha-2b alone and 14 IFN in combination with RBV. The proliferative immune responses of peripheral blood mononuclear cells to hepatitis C virus peptides and the lymphocyte activation markers (CD25+, CD38+ and CD69+) were assessed before treatment, at 1 week, and 1, 3 and 6 months of treatment. Cytokines interleukin (IL)-2, IFN-gamma, IL-4 and IL-10 were determined in supernatants before onset of treatment and at 1 and 6 months thereafter. Stimulation indices (SI) were higher in the sustained responders (SR), in comparison with those with no response (NR), before treatment (5.2 +/- 3.7 to 3.3 +/- 1.9, P = 0.028) and also at 6 months (7.8 +/- 1.9 to 4.1 +/- 1.2, P = 0.021). Patients with SR also had high SI to NS3 when compared with those with transitory response or no response (NR) (4.9 +/- 2.5 and 3.3 +/- 1.1, P = 0.033). At 1 month, SR had higher supernatant IL-2 than those with NR (133.8 +/- 119.2 to 56.0 +/- 89.3 pg/mL, P = 0.023) and lower levels of IL-10 (13.8 +/- 10.1 and 167.1 +/- 272.0 pg/mL, P = 0.023) in response to NS3. Combination therapy induced a higher percentage of the lymphocyte activation markers CD69+ and CD38+. In conclusion, we found that SR is associated with higher CD4+ proliferation particularly in response to the NS3 region, promoting a T-helper (Th)1/Th0 profile of cytokines, and that combination therapy induced a higher percentage of lymphocyte activation than therapy with IFN alone.

As popular strategies used by numerous viruses, interception of interferon (IFN) signaling and inhibition of IFN-induced antiviral functions allow viruses to evade the host immune response and set up successful infections. Hepatitis C virus (HCV), the leading cause of chronic liver disease worldwide and a major public health hazard, causes persistent infection in the majority of infected individuals. IFN-based therapies, currently the only ones available for HCV infection, have been unable to eliminate viral infection in the majority of patients, and many studies suggest that HCV possesses mechanisms to antagonize the IFN-induced antiviral response. Multiple viral, host, and IFN-associated factors have been implicated in the interplay between HCV and IFN. Two viral proteins, NS5A and E2, became the focus of much attention and extensive study because of their abilities to inhibit IFN-induced, double-stranded RNA-activated protein kinase (PKR), a major mediator of the IFN-induced biologic response, and to perturb the IFN signaling pathway. In this review, we discuss the significance of the interferon sensitivity determining region (ISDR) within NS5A, which has been the subject of intense debates. In addition, we discuss the potential mechanisms by which NS5A interferes with IFN signaling and the current working models. Further understanding of the molecular mechanisms underlying the interaction between HCV and IFN will likely facilitate improvement of current IFN-based therapies and development of novel treatments for the HCV pandemic. Future HCV research will benefit from both the development of efficient, convenient model systems for viral propagation, and the utilization of high throughput, genomic-scale approaches.

The aim of this study was to assess the immunological profile in hepatitis C virus carriers with persistently normal serum transaminase levels. Forty-two serum HCV RNA positive patients with persistently normal serum transaminase levels (22 natural 'asymptomatic HCV carriers' and 20 biochemical responders to IFN therapy) and 23 complete responders to IFN therapy were enrolled. The HCV genotypes and serum HCV RNA levels were determined before IFN therapy in treatment responders, and at entry in the others. The serum levels of IFN-inducible protein-10 (IP-10) (a protein mainly induced by IFN-gamma), interleukin (IL)-10, and IL-4 were measured in all patients while the serum transaminase levels were normal. The serum transaminase levels and platelet counts were then monitored for the next 4 years and the changes in liver fibrosis were assessed. The serum levels of IP-10 in infected and biochemically normal patients were significantly higher than the levels in complete responders to therapy, whereas the serum levels of IL-10 and IL-4 did not vary significantly among the different groups. During the 4-year follow-up period, 10/20 (50%) biochemical responders and 12/22 (55%) asymptomatic carriers had an elevation of the serum transaminase levels. A significant (P=0.0370) increase in platelet count after 4 years and improvement in liver fibrosis were noted in treatment responders but not in infected patients. The weak but significant residual immune response as reflected by the increased serum IP-10 level may underlie the outcome of HCV carriers with persistently normal serum transaminase levels.

Recurrence of hepatitis C after liver transplantation is an almost universal occurrence. T-cell derived cytokines have an important role in the development of liver damage associated with chronic hepatitis C, their post-transplant levels, however, have not been correlated with histologic recurrence of the disease.

We sought to analyze levels of TNF-alpha, soluble IL-2 receptor, IL-4 and IL-10 at 1 month, 6 months and 1 year after transplantation in 27 patients undergoing transplantation for hepatitis C related end-stage liver disease.

HCV RNA levels were monitored by a branched-chain DNA signal amplification assay. Diagnosis of recurrent hepatitis was based on 1-year protocol biopsies and on biopsies performed for liver enzyme elevations.

Recurrent hepatitis C was detected in 52% (n=14) of the 27 patients. HCV RNA levels rose over time in all patients regardless of histologic recurrence. TNF-alpha, and IL-4 levels, although elevated, did not show specific patterns over time or in correlation with recurrence. Similarly, the early elevation followed by a gradual decrease over the first year in the amount of soluble IL-2 receptor was not related to histologic recurrence. We observed a significant increase in circulating IL-10 levels over the first year in patients with biopsy-proven recurrence, while patients with no signs of histologic recurrence displayed increased, but steady levels.

These results suggest that while these cytokines are associated with post-transplant recurrence of hepatitis C, their production may be altered by additional factors.

To determine the profile of cytokine secretion by CD4+ T helper (Th) cells in chronic hepatitis C virus (HCV) infection, we used flow cytometry to determine the percentage of interferon (IFN)-gamma and interleukin (IL)-4 producing cells from CD4+ T lymphocytes in peripheral blood obtained from patients chronically infected with HCV.

Peripheral blood mononuclear cells isolated from 89 HCV infected subjects (22 asymptomatic carriers, 56 patients with chronic hepatitis, and 11 patients with liver cirrhosis) and 24 healthy controls were stained with surface CD4 and intracellular IFN-gamma and IL-4. Serum soluble IL-2 receptor (sIL-2R) levels were analyzed by ELISA.

The frequency of IFN-gamma producing CD4+ cells in asymptomatic HCV carriers, patients with chronic hepatitis, and patients with liver cirrhosis were significantly higher than those of healthy controls (p<0.01, respectively). In contrast, the percentages of IL-4-producing CD4+ cells were very low, and there were no significant correlations with disease progression. A significant elevation in serum sIL-2R levels was found in chronic HCV infection compared to healthy controls, and serum sIL-2R levels significantly correlated with the frequency of IFN-gamma-producing cells.

In HCV infected subjects, both serum sIL-2R and IFN-gamma are increased in chronic HCV infection no matter the stage of disease, meaning they are no different in asymptomatic carriers, patients with chronic hepatitis, and patients with liver cirrhosis, and that Th1 cytokine or Th1 cells may participate in the pathogenesis of liver damage in chronic HCV infection.

T lymphocytes and immunoregulatory cytokines play an important role in the host response to hepatitis C virus (HCV) infection. Zinc is required for a wide spectrum of immune functions, including T-cell activity. To determine the clinical significance of the cytokines sIL-2R, IL-6, TGF-beta1, neopterin, and of zinc in chronic heptatitis C virus (HCV) infection, we investigated their concentrations in the serum of 16 patients with chronic HCV infection before, during and at the end of therapy with interferon (IFN) alpha (Roferon A), and after 6 months follow-up. Elevated concentrations of sIL-2R, IL-6, TGF-beta1, and neopterin were found in the serum of all patients prior to therapy, as compared to healthy controls. sIL-2R patterns differed in responders and non-responders. While the mean concentration of sIL-2R (335.75 pg/ml) before therapy was about 40% higher in complete responders (n=4) than in controls (272.20 pg/ml), the mean concentration in non-responders (n=6) was 4-fold higher than in controls (1153.33 pg/ml). During therapy, sIL-2R levels in responders decreased by about 40%. Mean IL-6 concentrations in both complete and partial responders (n=6) decreased continuously during treatment, while mean concentrations in non-responders decreased for only a short time, and increased again after cessation of therapy. Mean levels of TGF-beta1 behaved similarly to those of IL-6. Only negligible differences in mean neopterin levels were found between responders and non-responders over the entire observation time. The mean serum zinc concentrations slightly decreased in all 3 patient groups, the greatest reduction occurring in 3 of the 4 responders. The present findings underscore the importance of the immune system in the pathogenesis of chronic HCV infection. Serum sIL-2R levels may be used as a serological marker of outcome following IFN-alpha treatment.

High serum levels of the soluble interleukin 2 receptor (sIL-2R) have been reported in patients with chronic hepatitis C. The aims of this study were to determine the evolution of sIL-2R considered as an indicator of activation of T cells in patients with hepatitis C virus (HCV) treated with IFN-alpha and to correlate sIL-2R serum levels with parameters reflecting ongoing liver disease and with outcome of interferon treatment.

In a case-control study, we studied patients enrolled in a multicenter randomized clinical trial which had demonstrated the benefit of a reinforced regimen of interferon alpha. Each of the 26 sustained virological responders (SVR) was paired for treatment regimen with two non-responders (NR).

Prior to treatment, higher levels of sIL-2R were found in the sera of 78 patients compared with healthy controls (3791+/-210 pg/ml versus 956+/-88 pg/ml (p<0.001)). In the 78 patients after 4 weeks of treatment, the levels of sIL-2R were higher than pretreatment levels (4308+/-206 pg/ml (p<0.01)). In the NR, levels of sIL-2R increased significantly after 4 weeks of treatment compared with pretreatment levels (p<0.01), and levels of sIL-2R at week 72 were not significantly different from those at pretreatment. Conversely, in the SVR, levels of sIL-2R at week 4 did not significantly increase compared to pretreatment values, and thereafter gradually decreased. At week 72, levels of sIL-2R were significantly lower than before treatment (p<0.001). The difference between levels of sIL-2R at week 4 and before initiation of treatment (delta s IL-2R) was smaller in the SVR than in the NR (142+/-219 pg/ml versus 704+/-107 pg/ml (p<0.02). The disappearance of HCV RNA from the serum at week 4 showed a sensitivity of 92% (95% confidence interval 86-98) and a specificity of 60% (95% confidence interval 49-71), delta sIL-2R had a sensitivity of 42% (95% confidence interval 31-53) and a specificity of 81% (95% confidence interval 79-90) for the prediction of a sustained virological response 6 months after stopping treatment. The disappearance of HCV RNA from serum at week 4 and delta sIL-2R were independent and early predictive factors for a sustained virological response 6 months after stopping treatment.

At week 4, delta sIL-2R may be a more specific parameter than the disappearance of HCV RNA for assessing total, and hence more sustained, elimination of HCV infection 6 months after stopping treatment.

The aim of this study was to understand the significance of the tumor necrosis factor receptor (TNFR)-mediated signaling pathway in the pathophysiology of chronic hepatitis C.

The serum levels of soluble TNFRs (sTNFRs; sTNFR p55 and sTNFR p75) were measured in 84 patients with chronic hepatitis C virus (HCV) infection (24 sustained responders and 25 nonresponders to interferon [IFN] therapy and 35 patients with persistent normal blood chemistries) and 20 healthy controls, then compared with clinical parameters.

The serum levels of sTNFRs increased in proportion to the severity of liver disease. The levels of sTNFRs revealed significant correlations with the serum levels of alanine aminotransferase, aspartate aminotransferase, gamma-glutamyl transpeptidase, and gamma-globulin, but not with the serum levels of HCV-core protein. In the sustained responder group, the levels of sTNFR p75 showed a significant decrease (p < 0.0002) 1 yr after IFN therapy, although the levels of sTNFR p55 did not. The levels of sTNFR p75 were correlated with the serum levels of macrophage-colony stimulating factor both before and after IFN therapy. In the nonresponder group, the levels of both sTNFRs were unaltered after IFN therapy.

The TNF alpha-TNFRs system, especially the TNFR p75-mediated pathway, is involved in the hepatic inflammation-fibrosis process in chronic hepatitis C. The serum levels of sTNFR p75, but not sTNFR p55, were correlated with the serum levels of macrophage colony stimulating factor in this process.

Changes in CD4 + cell levels and other immune parameters have been reported to occur during pregnancy but the timing of these alterations and their relationship to changes in immune function have not been well characterized. In addition, the influence of sociodemographic, obstetric, and other covariates on these relationships is largely unknown. We measured three immune activation markers, soluble interleukin-2 receptor (sIL-2Ralpha), soluble CD8 antigen (sCD8), and neopterin during pregnancy and postpartum in 170 HIV-1-seronegative women enrolled in the Mothers and Infants Cohort Study. Ante-partum and postpartum changes in these markers were examined using multivariable longitudinal random effects models. Neopterin levels began to rise well before delivery and were in decline by 2 months postpartum. sIL-2Ralpha and sCD8 levels increased at or near delivery and peaked by 2 months postpartum. After adjustment for other variables, the peak in sIL-2Ralpha was greater among women with pre-term than full-term deliveries (P = 0.05). All three markers were higher in whites than non-whites and in 'hard' drug users than non-users (P < or = 0.001 for each). After adjustment for these and other variables, hepatitis C virus (HCV) seropositivity was associated with higher levels of sCD8 and neopterin (P < or = 0.001 for each) but not sIL-2Ralpha (P = 0.27). These longitudinal data indicate that a state of broad immune activation develops at or near delivery. A number of maternal variables appear to influence the magnitude of these changes.

T helper type 1 (Th1) cytokines play an important role in antiviral defence. The purpose of this study was to quantify by ELISA IL2, soluble receptor of IL2 (IL2Rs), IFNgamma TNFbeta, IL4, IL6 and IL10 levels in the sera of 134 HCV-positive patients, 69 of whom were coinfected with HIV, and in 54 HIV-HCV-negative patients. The mean IL2Rs and IFN serum levels were much higher in patients with anti-HCV than in the control group, whereas the mean IL4 and IL6 levels were lower in patients infected with HCV. There were no significant differences in cytokine levels between patients with and without HIV. There were significantly less patients with HCV than controls with IFNgamma levels under cut-off, and significantly more patients with HCV with IL4 levels under cut-off. Although serum level of cytokines must be interpreted with caution, the results suggest that Th1 response is enhanced in HCV infection.

The efficacy of long-term, high dose interferon-alpha (IFN-alpha) therapy was studied in seven patients with HTLV-I-associated myelopathy (HAM)/tropical spastic paraparesis (TSP). IFN-alpha was administered at a dose of 6 x 10(6) international units daily for the initial 2 weeks and thereafter 3 times a week for the following 22 weeks. Five patients showed a sustained improvement in motor performance during and up to 6 months after the completion of IFN-alpha. The other patient who responded to IFN-alpha initially dropped out at 3 months because of depression, while another patient first deteriorated and thereafter dropped out. In the six responders, the absolute number of peripheral blood lymphocytes (PBL) harboring the HTLV-I genome as evaluated by the quantitative polymerase chain reaction method decreased significantly during the therapy period (28.6 +/- 16.6% reduction, P = 0.0083), whereas the one deteriorated patient showed a 2.5-fold increase in HTLV-I-infected cells. The autoproliferation of CD4+ T clone cells from a single cell culture was markedly depressed even after the cessation of IFN-alpha in the responders who completed long-term IFN-alpha therapy. In addition, the CD8+DR+ T cells in the peripheral blood and soluble IL-2 receptor levels in the sera increased significantly during the therapy in all patients (P = 0.0431 and P = 0.0041, respectively). Therefore, the results of our study suggested that both the reduction of HTLV-I proviral DNA load and immunomodulation by long-term IFN-alpha therapy contributed to its sustained clinical benefits.

To verify its value with regard to the outcome of therapy in chronic hepatitis C, serum interferon-alpha (IFN) was measured by ELISA in 70 patients (43 male, 27 female) with chronic hepatitis C, treated with IFN 9 MU/week subcutaneously for up to one year. Serum IFN was detectable in 49/70 patients, 16 of whom had IFN values >125 pg/ml. Only 1/22 patients who maintained a sustained response six months after the end of treatment had pretreatment serum IFN > 125 pg/ml, in comparison to 15/48 patients who did not respond or who relapsed (chi2 6.1, P < 0.02). At multivariate analysis the predictive value of serum IFN was independent of age, sex, presence of cirrhosis, infection by genotype 1b (improvement chi2 7.1, P < 0.01). In patients with chronic hepatitis C, measurement of serum IFN at baseline might be useful for the selection of patients with higher probability of long-term response.

Polymorphonuclear cell (PMN) oxidative metabolism, lymphocyte polyclonal proliferation and monocyte HLA class I antigen expression were evaluated at different intervals of time in patients with chronic hepatitis C (CH-C) subjected to a 6 month interferon alpha (IFN-alpha) treatment and divided into Responder ('R') and Nonresponder ('NR') subsets according to clinical outcome. Before therapy, all subjects exhibited multiple immune alterations even if to a different extent between 'R' and 'NR' subsets: an elevated superoxide anion (O2-) generation by suspended PMN, a failure to further increase neutrophil oxidative responsiveness under adherence conditions, an augmented phytohaemagglutin-induced lymphocyte proliferative capacity and an enhanced HLA class I antigen expression on CD14+ cells. IFN-alpha administration gave rise to a modulation of oxidative response in 'R' group only, since these individuals displayed an O2- release by suspended and adherent PMN which fell within normal values. At the same time, a decrease of lymphocyte proliferation occurred in both groups of patients during IFN-alpha therapy, even if it reached statistical significance in 'R' group only. Finally, a more marked difference between 'R' and 'NR' individuals was noted in terms of HLA class I antigen induction on CD14+ cells at the end of therapy, as a consequence of a reduced expression of these structures in 'NR' subjects. Altogether, these findings suggest the occurrence of a strict relationship between immunoresponsiveness and IFN-alpha induced therapeutical effects in CH-C patients.