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INTRODUCTION: AXA1125 and AXA1957 are novel, orally administered endogenous metabolic modulator compositions, specifically designed to simultaneously support multiple metabolic and fibroinflammatory pathways associated with nonalcoholic fatty liver disease (NAFLD). This study assessed safety, tolerability, and biologic activity of AXA1125 and AXA1957 in NAFLD. METHODS: In this multicenter, 16-week, placebo-controlled, single-blind, randomized clinical study in subjects with NAFLD stratified by type 2 diabetes, AXA1125 24 g, AXA1957 13.5 g or 20.3 g, or placebo was administered twice daily. Key metabolism (MRI-proton density fat fraction [MRI-PDFF] and homeostasis model assessment of insulin resistance [HOMA-IR]) and fibroinflammation markers (alanine aminotransferase [ALT], corrected T1 [cT1], keratin-18 [K-18] M65, and N-terminal type III collagen propeptide [Pro-C3]) were evaluated. Safety outcomes included adverse events and standard laboratory assessments. RESULTS: Baseline characteristics of the 102 enrolled subjects, including 40 with type 2 diabetes, were consistent with presumed nonalcoholic steatohepatitis. AXA1125 showed consistently greater biologic activity than AXA1957 or placebo. Week 16 changes from baseline with AXA1125 vs placebo: MRI-PDFF −22.9% vs −5.7%, HOMA-IR −4.4 vs +0.7, ALT −21.9% vs −7.2%, K-18 M65 −13.6% vs +20.1%, cT1 −69.6 vs +18.3 ms (P < 0.05), and Pro-C3 −13.6% vs −3.6%. Week 16 changes from baseline with AXA1957 20.3 g: MRI-PDFF −8.1%, HOMA-IR +8.4, ALT −20.7%, K-18 M65 6.6%, cT1 −34.7 ms, and Pro-C3 −15.6%. A greater proportion of subjects treated with AXA1125 achieved clinically relevant thresholds: ≥30% MRI-PDFF, ≥17-IU/L ALT, and ≥80-ms cT1 reductions at week 16. Study products were safe and well tolerated with stable lipid and weight profiles. DISCUSSION: Both compositions showed multitargeted activity on relevant NAFLD pathways. AXA1125 demonstrated the greatest activity over 16 weeks, warranting continued clinical investigation in nonalcoholic steatohepatitis subjects.

SUMMARY. To evaluate T cell immunity in advanced liver disease, antigen-specific lymphoproliferative (LP) responses were prospectively studied in the context of the Hepatitis C Antiviral Long-term Treatment against Cirrhosis trial. Peripheral blood responses to hepatitis C virus (HCV), tetanus and Candida protein antigens were measured at baseline, month 12 (M12), M24, M36 and M48 in 186 patients randomized to either low-dose peginterferon-alfa-2a (PEG-IFN) onlyorobservation.Liverhistologywasevaluatedatbaseline, M24 and M48. Patients with cirrhosis (Ishak 5‐6) were less likely to have positive LP responses to HCV at baseline than patients with fibrosis (15% vs 29%, P = 0.03) and had lower levels of HCV c100 responses at baseline, M24 and M48 (P = 0.11, P = 0.05, P = 0.02, respectively). For 97 patients with complete longitudinal data, the frequency of positive LP responses to HCV, tetanus and Candida antigens declined over time (P < 0.003), and the slope of this decline was greater in the PEG-IFN treatment group than the observation group (P < 0.02). Lower levels of tetanus LP responses were associatedwithfibrosisprogressionandclinicaloutcomes(P= 0.009). Poorer CD4+ T cell proliferative function was associated with more advanced liver disease in chronic hepatitis C and may be further affected by long-term PEG-IFN treatment.

HIV-infected persons are at risk for HBV co-infection which is associated with increased morbidity and mortality. Unfortunately, protective immunity following HBV vaccination in HIV-infected persons is poor. This randomized, phase II, open-label study aimed to evaluate efficacy and safety of 40 mcg HBV vaccine with or without 250 mcg GM-CSF administered at day 0, weeks 4 and 12. HIV-infected individuals >or=18 years of age, CD4 count >or=200 cells/mm(3), seronegative for HBV and HCV, and naive to HBV vaccination were eligible. Primary endpoints were quantitative HBsAb titers and adverse events. The study enrolled 48 subjects. Median age and baseline CD4 were 41 years and 446 cells/mm(3), 37 were on ART, and 26 subjects had undetectable VL. Vaccination was well tolerated. Seven subjects in the GM-CSF arm reported transient grade >or=2 signs/symptoms (six grade 2, one grade 3), mostly aches and nausea. GM-CSF had no significant effect on VL or CD4. Four weeks after vaccination, 26 subjects (59%) developed a protective antibody response (HBsAb >or=10 mIU/mL; 52% in the GM-CSF arm and 65% in the control arm) without improved Ab titer in the GM-CSF vs. control arm (median 11 mIU/mL vs. 92 mIU/mL, respectively). Response was more frequent in those with CD4 >or=350 cells/mm(3) (64%) than with CD4

Hepatitis C virus (HCV) induces persistent infection and causes chronic liver disease in most infected patients. Vigorous HCV-specific CD4+ and CD8+ T cell responses against HCV multiple epitopes are necessary for spontaneous viral clearance during the acute phase, but the virus appears to have multiple strategies to evade these defenses. There are relatively few studies on the role of immune responses during the chronic phase of infection. CD4+ T cell responses appear to protect against liver injury and may be important to clearance during interferon and ribavirin based therapy. Classic cytotoxic T cells (CTL) may primarily damage the liver in chronic HCV, but there may be subpopulations of T cells that protect against liver inflammation. Resolution of these outstanding questions is important to the development of a prophylactic vaccine as well as improving therapeutic options for those with chronic infection.

Documented treatment rates for Hepatitis C virus (HCV) infection are low. Within this cohort of HCV-infected patients (N = 373), participants who were not actively injecting drugs or not co-infected with HIV were most likely to initiate HCV treatment. Persons of white race and HIV-infected participants with a CD4 count above 200 were also more likely to have initiated HCV treatment. We defined five factors as potentially modifiable, and found almost all (90%) of the cohort had at least one such factor. Participants with more than one of these factors were least likely to initiate treatment. The proportion of patients receiving treatment increased as their number of modifiable risk factors decreased (p < 0.01, for trend). Focused strategies to overcome these potentially modifiable factors may be indicated to increase HCV treatment in affected populations.

Liver disease due to chronic HBV or HCV infection is becoming a leading cause of death among persons with HIV infection. Both the risk of hepatocellular carcinoma and the risk of hepatotoxicity due...

BACKGROUND Ongoing substance use is a potential confounder for immunological studies on hepatitis C virus (HCV), but there is little in the literature regarding the effects of injection drug use (IDU) or alcohol on HCV-specific immune responses. We wanted to determine whether IDU or alcohol affected immune responses in HCV-infected and human immunodeficiency virus (HIV)/HCV coinfected subjects. METHODS Eight-four subjects with HIV/HCV and 57 with HCV were classified as either injection drug users, drinkers, or nonusers based on questionnaire results. Immune responses were studied with enzyme-linked immunosorbent spot assay for interferon (IFN)- gamma , interleukin (IL)-10, and tumor necrosis factor (TNF)- alpha against HCV proteins Core, NS3, and NS5 and recall antigens. RESULTS Subjects with HIV/HCV, in aggregate, had significantly lower HCV-specific IFN- gamma and TNF- alpha responses than subjects with HCV. However, HIV/HCV injection drug users had HCV-specific IFN- gamma and IL-10 responses that were similar to those of HCV injection drug users and were significantly higher than in nonusers with HIV/HCV. Conversely, subjects who drank alcohol had similar immune responses to those who were abstinent, among both subjects with HIV/HCV and subjects with HCV. CONCLUSIONS Studies that examine IFN- gamma or IL-10 immune responses in HIV/HCV-coinfected or HCV-infected persons need to consider current IDU. Alcohol, at levels consumed in this cohort, does not appear to have as much of an effect on antigen-specific immune responses.

Background/Aims: The contribution of the host immune response to sustained virologic response is not clear in patients with chronic hepatitis C (CHC). The aim of this study was to explore the relationship of the toll-like receptor (TLR) expression with the outcome of antiviral therapy in hepatitis C viral infection. Methods: Peripheral blood mononuclear cells (PBMC) were obtained from 15 CHC patients before a 48-week treatment with pegylated interferon (PEG IFN) α-2a and ribavirin. A multiplex semi-quantitative reverse-trancriptase polymerase chain reaction (RT-PCR) was used to compare the relative abundance of TLR2–9 transcripts. Results: mRNA levels of TLR2, 3 and 6 were significantly higher in CHC subjects compared with normal controls (n=8). When patients were classified into non-responders (n=8) and sustained virological responders (n=7) according to the virological outcome of the treatment, there was a clear difference in baseline mRNA expression of TLRs and T-helper (Th) 1/2 cytokines. In addition, the mRNA expression of IFN-γ and nuclear factor of activated T cells (NFAT), which is exclusively expressed in activated T cells, was inversely correlated with that of TLR4, 6 and 9 in non-responders. Conclusions: TLRs mRNA levels are differentially expressed in baseline PBMC of chronic HCV-infected subjects with or without responsiveness to antiviral therapy.

There is growing evidence that cytokine expression is linked to hepatitis C virus (HCV) pathogenesis and treatment response rates among HCV-monoinfected persons. However, because of the profound effects of human immunodeficiency virus (HIV) coinfection on HCV, it is not clear if these observations are also true for HCV/HIV-coinfected individuals. Serum expression of the proinflammatory cytokines interleukin-8 (IL-8) and tumor necrosis factor-alpha (TNF-alpha) and the fibrogenic cytokine transforming growth factor-beta1 (TGF-beta1) were measured in HCV/HIV-coinfected persons at baseline and at week 24 of HCV therapy. Higher levels of IL-8 and TGF-beta were demonstrated among nonwhite subjects at baseline. Increases in TNF-alpha and IL-8 expression were found at week 24 of HCV therapy, suggesting that enhanced proinflammatory cytokine production may occur during HCV treatment. However, cytokine levels were not predictive of HCV virologic, biochemical, or histologic response. Although previous studies conducted among HCV-monoinfected individuals have suggested that cytokine levels could predict the virologic response to therapy, no such associations were observed among HCV/HIV-coinfected persons, suggesting that they may respond differently to treatment than do their HCV-monoinfected counterparts.

Serial liver biopsies are the gold standard by which the progression of fibrosis is evaluated. This longitudinal cohort study assessed the different rates in the progression of fibrosis using serial liver biopsies and serum fibrosis markers YKL-40 and PIIINP and the cytokines, transforming growth factor beta (TGF-beta) and tumor necrosis factor alpha (TNuF-alpha). A 10-year cohort study was performed in patients with hepatitis C virus (HCV) alone or HCV and schistosomiasis. Patients were enrolled at the time of acute HCV infection and prospectively evaluated with two liver biopsies (at entry and end of follow-up), and true rates in the progression of fibrosis were calculated per year. Serum YKL-40, N-terminal propeptide of collagen III (PIIINP), TGF-beta, and TNF-alpha were measured, as well as the expression of TGF-beta, TNF-alpha, and YKL-40 mRNA in liver tissue. A significant increase in the progression rates of fibrosis occurred in the coinfected group (0.61 +/- 0.13) compared with the HCV monoinfection group (0.1 +/- 0.06; P < .001)). The progression of fibrosis rate/year had a direct linear correlation for YKL-40 (r = 0.892, P < .001) and for PIIINP (r = 0.577, P < .01). YKL-40 showed a linear correlation with TGF-beta (r = 0.897, P < .001). Hepatic mRNA levels of YKL-40 and TGF-beta correlated with the serum levels, confirming a hepatic source for the elevated serum levels. In conclusion, serial cytokine and fibrosis markers can accurately determine the rate at which fibrosis is progressing, identifying both those with rapid fibrosis and those with stable disease.

Background & Aims: Pegylated interferon therapy has not been adequately evaluated in acute hepatitis C virus (HCV) infection. This randomized trial assessed the efficacy, safety, and timing of pegylated interferon alfa-2b for treatment of acute hepatitis C. Methods: One hundred seventy-five patients acutely infected with HCV were screened. Patients whose infection did not spontaneously resolve by week 8 were randomized to once weekly peginterferon alfa-2b monotherapy (1.5 μg/kg per week) started at weeks 8, 12, or 20 for a duration of 12 weeks. The primary endpoint was undetectable HCV RNA 24 weeks after the end of treatment (sustained virologic response [SVR]). All patients were followed for 48 weeks after cessation of therapy. Results: One hundred twenty-nine subjects started treatment at week 8 (group A, n=43), week 12 (group B, n=43), or week 20 (group C, n=43). By using an intent-to-treat analysis, the overall SVR rate was 87%. The SVR rates were 95%, 92%, and 76% with treatment onset at 8, 12, and 20 weeks, respectively. Overall, SVR rates were better for patients infected with genotypes 2, 3, and 4 than those infected with genotype 1. Earlier initiation of therapy improved SVR rates for patients infected with genotype 1 with high viral load. Peginterferon alfa-2b was well tolerated. Subjects with SVR maintained undetectable HCV RNA 48 weeks after therapy. Conclusions: Peginterferon alfa-2b monotherapy in acute hepatitis C induces high sustained virologic response rates, prevents chronic evolution, and is well tolerated. Initiation of treatment at week 8 or 12 results in higher sustained virologic rates than initiation at week 20.

The role of CD4(+) or CD8(+) T cells in chronic hepatitis C virus (HCV) infection is unclear. People with chronic infection have weak responses against HCV in the blood, but HCV-specific responses are present within liver. The prevailing hypothesis of liver injury in HCV is that CD4(+) and CD8(+) T cell responses mediate HCV-related liver damage but are ineffectual at clearing the chronic infection. However, we recently reported that vigorous CD4(+) responses that produce interferon gamma (IFNgamma) early in infection are correlated with slower rates of disease progression, and compartmentalize to the liver. People with chronic HIV and HCV co-infection, particularly those with CD4(+)200 cells/mm(3), have a higher rate of fibrosis development and severe liver disease. Co-infected people have variable degrees of immunosuppression that may provide insight into the relationship between cellular immune functions and the degree of liver damage as assessed by liver biopsy. People with co-infection may have quantitative or qualitative differences in the immune responses. We recently found a relationship between CD4(+) immune responses and liver histology. There are qualitative differences in the CD4(+) responses found in the liver in co-infected people compared to those with HCV alone, whereas no such differences are found when CD8(+) responses are measured. Neither CD4(+) nor CD8(+) responses correlate with the peripheral CD4 count.

Background: Noninvasive markers of hepatic fibrosis hold great promise to stage liver fibrosis and to monitor disease progression. To date, few studies have assessed the performance of the currently available markers of hepatic fibrosis in HIV-infected cohorts. The aim of the current study was to compare the diagnostic performance and characteristics of a number of noninvasive markers of hepatic fibrosis in populations of hepatitis C virus (HCV)-infected patients with and without HIV infection. Methods: A sample of 97 subjects (40 HCV/HIV-coinfected, 57 HCV-infected) undergoing liver biopsy as part of an ongoing prospective cohort study was evaluated. Liver biopsies were assessed by a single hepatopathologist and scored according to Ishak criteria. Noninvasive markers of fibrosis studied included international normalized ratio, platelet count, aspartate aminotransferase (AST)/alanine aminotransferase ratio, AST platelet ratio index (APRI), Forns index, procollagen III N peptide, hyaluronic acid, and YKL-40. Results: The correlations between fibrosis markers with the stage of fibrosis and the diagnostic performance of each of the tests were similar in the groups with and without HIV infection. Although a trend to improved diagnostic performance in the HCV/HIV-coinfected group was observed, this may be related to the small sample size. Conclusions: The diagnostic performance of the evaluated noninvasive markers of liver fibrosis is equivalent in HCV/HIV-coinfected and HCV-infected subjects. These tests may be of value for the clinical evaluation of HCV/HIV-coinfected patients and warrant further study.

Hepatitis C virus (HCV) infection is associated with inflammation of liver endothelium, which contributes to the pathogenesis of chronic hepatitis. The mechanism of this endothelitis is not understood, since the virus does not appear to infect endothelial cells productively. Here, an ‘innocent bystander’ mechanism related to HCV proteins was hypothesized and it was investigated whether the binding of HCV particles to human endothelium induced functional changes in the cells. Exposure of human umbilical vein endothelial cells (HUVECs) to HCV-like particles (HCV-LPs) resulted in increased interleukin 8 (IL8) production and induction of apoptosis. The IL8 supernatants collected after stimulation of HUVECs with HCV-LPs, BV-GUS (control baculovirus containing β-glucuronidase) and appropriate controls were used to assay the transendothelial migration of neutrophils. This assay confirmed that HCV-LP-induced IL8 was functionally active. Using specific NF-κB inhibitors, it was also shown that HCV-LP-induced NF-κB activity mediated IL8 production in HUVECs. Apoptosis appeared to be mediated by the Fas/Fas-L pathway, as neutralizing antibodies for Fas and Fas-L significantly protected HUVECs against HCV-LP-induced apoptosis. Treatment of HUVECs with HCV-LPs also enhanced cellular Fas-L expression and augmented caspase-3 activation. This was confirmed by using a specific caspase-3 inhibitor, Z-Asp-Glu-Val-Asp-fluoromethyl ketone. As shown by blocking of specific chemokine receptors for IL8 on HUVECs, the induction of IL8 did not appear to contribute to HCV-LP-induced apoptosis. These results suggest that HCV proteins can trigger the release of inflammatory chemokines such as IL8 and cause endothelial apoptosis, thereby facilitating endothelitis.

Cellular immune responses are typically important in recovery from acute infections, and studies of acute hepatitis C confirm that broadly directed CD4 + and CD8 + T cell responses are associated with spontaneous clearance of infection. However, a major unanswered question is what role the cellular immune response plays in progression of liver disease during chronic infection. Classic models of hepatitis C suggest that cellular immune responses promote liver injury, either by causing direct cytolysis of infected cells or by promoting inflammation. However, clinical evidence suggests that persons with cellular immune dysfunction, such as that due to with human immunodeficiency virus (HIV) infection, have more-rapid disease progression. Recent data suggest that cellular immune responses do serve to limit the progression of liver disease, even if they are ineffective at clearance of virus. There is limited information on the effect of HIV coinfection on the cellular immune response to hepatitis C virus, but further study of this issue might shed light on the pathogenesis of liver disease in both immunocompromised and nonimmunocompromised hosts.

Acute hepatitis C virus (HCV) is typically defined as new viremia and antibody seroconversion. Rates and immunologic correlates of hepatitis C clearance have therefore been based on clearance of viremia only in individuals who initially had an antibody response. We sought to characterize the immunological correlates of clearance in patients with acute hepatitis C and their sexual contacts. We prospectively determined CD4+and CD8+cytotoxic T-lymphocyte responses in index patients with acute HCV and their sexual contacts who developed acute infection, either with or without spontaneous clearance, as well as those contacts who never developed viremia. Responses were measured using proliferation and ELISpot assays for CD4+and CD8+responses. We demonstrate in this prospective study that cellular immune responses can develop in exposed but persistently aviremic and antibody-negative individuals as well as those individuals with spontaneous clearance of acute HCV. These findings lend further credence to the importance of cellular immune responses in recovery from HCV and suggest that low exposure to HCV may lead to development of HCV-specific immune responses without ongoing HCV replication. This finding has important implications for HCV vaccine and therapeutic development.

Much of the hepatology literature to date has focused on the adaptive, antigen-specific response mediated by classical T-cell populations in both the protection and pathogenesis of liver disease. However, the liver is selectively enriched for cells representative of innate immunity, including natural killer T (NKT) cells. In particular, certain CD1d-reactive T cells are present at much higher frequencies in the liver than in the peripheral blood. Although these cells have previously been defined mostly on the basis of phenotypic markers, recent emerging literature regarding NKT cell populations has revealed considerable functional complexity. This review summarizes the recent literature regarding NKT cells, which may have important roles in a variety of liver diseases. Although there is an abundance of literature on the phenotype, distribution, and function of these cells in mice, much less is known about them in human health or liver diseases.

Chronic hepatitis C virus (HCV) infection is a cause of major complications in persons who are also infected with the human immunodeficiency virus (HIV). However, the treatment of HCV infection in such persons has been associated with a high rate of intolerance and a low rate of response. We conducted a multicenter, randomized trial comparing peginterferon plus ribavirin with interferon plus ribavirin for the treatment of chronic hepatitis C in persons coinfected with HIV.A total of 66 subjects were randomly assigned to receive 180 microg of peginterferon alfa-2a weekly for 48 weeks, and 67 subjects were assigned to receive 6 million IU of interferon alfa-2a three times weekly for 12 weeks followed by 3 million IU three times weekly for 36 weeks. Both groups received ribavirin according to a dose-escalation schedule. At week 24, subjects who did not have a virologic response (those who had an HCV RNA level greater than or equal to 60 IU per milliliter) underwent liver biopsy, and medications were continued in subjects with either a virologic response or histologic improvement.Treatment with peginterferon and ribavirin was associated with a significantly higher rate of sustained virologic response (an HCV RNA level of less than 60 IU per milliliter 24 weeks after completion of therapy) than was treatment with interferon and ribavirin (27 percent vs. 12 percent, P=0.03). In the group given peginterferon and ribavirin, only 14 percent of subjects with HCV genotype 1 infection had a sustained virologic response (7 of 51), as compared with 73 percent of subjects with an HCV genotype other than 1 (11 of 15, P0.001). Histologic responses were observed in 35 percent of subjects with no virologic response who underwent liver biopsy.In persons infected with HIV, the combination of peginterferon and ribavirin is superior to the combination of interferon and ribavirin in the treatment of chronic hepatitis C. These regimens may provide clinical benefit even in the absence of virologic clearance. The marked discrepancy in the rates of sustained virologic response between HCV genotypes indicates that strategies are needed to improve the outcome in persons infected with HCV genotype 1.

Pegylated interferon alpha (PEG IFN-alpha) improves sustained virological response rates in chronic hepatitis C, but neither its role in acute hepatitis C nor the biologic basis for its action has been defined. This prospective study assessed the efficacy of PEG IFN-alpha treatment in acute hepatitis C in relation to the kinetics of hepatitis C virus (HCV)-specific CD4(+) T cell responses during therapy and follow-up. Forty subjects with proven acute hepatitis C who received either PEG IFN-alpha plus ribavirin (n = 20) or PEG IFN-alpha monotherapy (n = 20) for 24 weeks in addition to 14 untreated subjects with acute hepatitis C were prospectively followed. Serum HCV RNA, HCV-specific CD4(+) T cell responses, and cytokine production were measured before and during therapy and at follow-up and correlated to the outcome. The sustained virological response rate was 85% with PEG IFN-alpha/ribavirin combination and 80% with PEG IFN-alpha monotherapy. Five untreated subjects had spontaneous recovery. The frequency, magnitude, and breadth of HCV-specific CD4(+) T helper 1 responses were significantly higher in treated subjects compared with untreated subjects with self-limited disease or subjects with chronic evolution. The CD4(+) T cell responses were maintained in subjects with sustained virological responses and self-limited disease but fluctuated in those who developed chronic infection. In conclusion, PEG IFN-alpha therapy in acute hepatitis induces high rates of sustained virological response and prevents choronicity, probably through efficient early stimulation of multispecific HCV-specific CD4(+) T helper 1 responses.

We hypothesized that hepatocytes exposed to hepatitis C virus (HCV) and human immunodeficiency virus (HIV) might be injured via an "innocent bystander" mechanism due to cell-surface binding of viral proteins. To assess this, we studied the effects of HCV envelope protein E2 and T-tropic HIV envelope glycoprotein gp120 on hepatocytes and saw potent apoptosis. Either viral protein alone did not induce this effect. HCV E2 and M-tropic HIV gp120 also induced significant apoptosis. Blocking the CXCR4 receptor led to a reduction in apoptosis. HCV E2 and HIV gp120 acted collaboratively to trigger a specific set of downstream signaling events, including up-regulation of the Fas ligand and dephosphorylation of the anti-apoptotic molecule AKT. These results suggest that hepatic injury may occur in HCV/HIV coinfection through the induction of novel downstream signaling pathways and provide a rationale for therapeutic interventions that interfere with specific receptors and signaling molecules.

Hepatitis B virus (HBV) infection is a major global health concern and is the most common cause of chronic liver disease worldwide. It is estimated that there are between 350 and 400 million individuals with chronic HBV infection. For many of these individuals, the current forms of therapy are suboptimal. The first problem is the limited lack of efficacy. Many patients either will not respond or will fail to have a durable sustained virologic response after treatment with either of the two available classes of agents, interferon-a and the nucleos(t)ide analogs (lamivudine or adefovir). Interferon alone, while effective in a subset of patients (33% for treated patients compared with 12% of untreated patients with respect to loss of HBeAg) [1], is notable for the substantial toxicity suffered by many patients. Lamivudine and adefovir, while better tolerated, similarly offer rates of HBeAg seroconversion in the range of 12–30% [2–6]. Since patients without virologic suppression can have substantial benefits in terms of histologic improvement [5–7], therapy with either lamivudine or adefovir is often continued so long as the patient has evidence of continued virologic suppression and a biochemical response to therapy. This leads to the second major problem, which is that long term use of lamivudine is accompanied by a progressive risk of viral resistance conferred by mutations in HBV polymerase [8,9]. The percent of patients with such resistance mutations increases with the duration of nucleoside therapy, from 14% at 1 year to as high as 38 and 67%, respectively, after 2 and 4 years [4]. Resistance to adefovir was recently reported as well [10], suggesting that neither agent alone will be successful as long term monotherapy. Both agents are also expensive, and particularly in developing nations there is a need for a less expensive therapy that is of short duration. New strategies may improve the efficacy and reduce the emergence of drug resistance. Drawing from the lesson of antiretroviral therapy of HIV, some studies have addressed the possibility of combination therapy. However, combinations of interferon and lamivudine to date have yielded mixed results, perhaps due to variations in the patient selection [11–13]. Although other drugs are in phase I/II trials, no agents have yet provided a highly durable sustained virologic response in the majority of treated patients. Therefore, it is important to understand the mechanisms involved to obtain long-lasting viral suppression and disease remission. The immune system appears to play a key role in the course and outcome of hepatitis B. In patients with self-limited acute hepatitis B, both CD4 þ T-helper and CD8 þ cytotoxic T-cell (CTL) responses to viral antigens are strong and multispecific, whereas these responses are weak or undetectable and narrowly focused in chronically infected patients [14]. The immune system also appears to be important for maintaining recovery. In patients with spontaneous resolution of HBV infection these strong and broad antiviral T-cell responses are usually maintained for decades after clinical recovery [15,16]. Patients with either inactive or resolved hepatitis B can experience reactivation with return of high levels of HBV antigens and DNA upon immunosuppression [17], emphasizing the importance of virus-specific immunity in maintaining control of viral replication. It is commonly held that the immune response is also important to response to treatment, at least as defined by HBeAg seroconversion. It has been known for years that spontaneous elevations in serum alanine aminotransferase (ALT) during chronic HBV infection may be followed by HBeAg seroconversion, which has been presumed to represent the augmentation of HBV-specific immunity. Similarly, pretreatment ALT values are predictive of HBeAg seroconversion, with a higher baseline ALT associated with a higher likelihood of such a response [18]. This suggests that patients with a stronger endogenous immune response against HBV have a better response to antiviral agents. Moreover, CTL directed to specific epitopes of the HBV, rarely detected in chronic hepatitis B carriers, have been noted to appear in the peripheral blood

Murine intrahepatic lymphocytes (IHL) are dominated by invariant TCR α-chain expressing CD1d-reactive NKT cells, which can cause model hepatitis. Invariant NKT (CD56+/−CD161+) and recently identified noninvariant CD1d-reactive T cells rapidly produce large amounts of IL-4 and/or IFN-γ and can regulate Th1/Th2 responses. Human liver contains large numbers of CD56+ NKT cells but few invariant NKT. Compared with matched peripheral blood T cell lines, primary IHL lines from patients with chronic hepatitis C had high levels of CD161 and CD1d reactivity, but the invariant TCR was rare. CD1d-reactive IHL were strikingly Th1 biased. IHL also demonstrated CD1d-specific cytotoxic activity. Hepatocytes and other liver cells express CD1d. These results identify a novel population of human T cells that could contribute to destructive as well as protective immune responses in the liver. CD1d-reactive T cells may have distinct roles in different tissues.

To investigate in this phase 2a study (ZENITH) the safety, tolerability, and antiviral activity of VX-222, a selective, non-nucleoside inhibitor of hepatitis C virus (HCV) NS5B polymerase, combined with various telaprevir-based regimens for treatment of genotype 1 HCV.In total, 152 treatment-naive patients received VX-222+telaprevir ('DUAL' regimen; n=47), with ribavirin ('TRIPLE' regimen; n=46), or with peginterferon+ribavirin ('QUAD' regimen; n=59) for 12 weeks. Patients with detectable HCV RNA at weeks 2 and/or 8 received peginterferon+ribavirin for 24 (DUAL and TRIPLE) or 12 (QUAD) additional weeks.VX-222 (100 or 400 mg twice daily) was well tolerated, with an increased rate of gastrointestinal adverse events observed with the higher dose. Across VX-222 400-mg twice-daily regimens, the QUAD was associated with the highest frequency of grade 3/4 adverse events. The DUAL was discontinued because of high viral breakthrough before week 12. Sustained virologic response (SVR) 24 weeks after end of treatment (SVR24), including patients treated with 12 or 24 additional weeks of peginterferon+ribavirin, was 67% for TRIPLE (VX-222 400 mg twice daily) and 79 and 90% for QUAD (VX-222 100 and 400 mg twice daily, respectively).These results provide valuable information regarding the safety, tolerability, and efficacy of telaprevir combined with a non-nucleoside polymerase inhibitor, as dual therapy or with ribavirin without or with peginterferon. Telaprevir and VX-222, alone or with ribavirin without or with peginterferon, were generally well tolerated, with improved tolerability without peginterferon. SVR24 rates achieved with TRIPLE and QUAD regimens containing telaprevir and VX-222 were comparable to those observed with telaprevir-based therapy.

Background & Aims: Immune responses during the first few months of acute hepatitis C virus (HCV) infection seem crucial for viral control, but the relationship of these responses to natural history is poorly characterized. Methods: This prospective study investigated the HCV-specific CD4 + and cytokine responses in patients with acute HCV hepatitis with or without Schistosoma mansoni coinfection, a parasitic infection with T helper (Th) 2 immune bias. HCV-specific CD4 + proliferative responses and cytokine production in peripheral blood mononuclear cells were correlated with liver biopsy results at 6 months and at the end of follow-up. Results: Whereas 5 of 15 patients with HCV alone recovered from acute HCV, all (17 of 17) patients with S. mansoni coinfection progressed to histologically proven chronic hepatitis. Coinfected patients had either absent or transient weak HCV-specific CD4 + responses with Th0/Th2 cytokine production. The magnitude of the HCV-specific CD4 + response at week 12 was inversely correlated with the fibrosis progression rate in chronically infected patients. Conclusions: Patients with acute hepatitis C and schistosomiasis coinfection cannot clear viremia and show rapid progression once chronic infection is established. This rapid progression is associated with a strong Th2 response in peripheral immune responses, suggesting that early development of vigorous Th1 responses not only facilitates clearance but delays disease progression. GASTROENTEROLOGY 2001;121:646-656

Studies have shown that rates of liver disease are higher in persons who are coinfected with human immunodeficiency virus (HIV) and hepatitis C virus (HCV) than they are in persons with HCV alone, but estimates of risk vary widely and are based on data for dissimilar patient populations. We performed a meta-analysis to quantify the effect of HIV coinfection on progressive liver disease in persons with HCV. Eight studies were identified that included outcomes of histological cirrhosis or decompensated liver disease. These studies yielded a combined adjusted relative risk (RR) of 2.92 (95% confidence interval [CI], 1.70-5.01). Of note, studies that examined decompensated liver disease had a combined RR of 6.14 (95% CI, 2.86-13.20), whereas studies that examined histological cirrhosis had a pooled RR of 2.07 (95% CI, 1.40-3.07). There is a significantly elevated RR of severe liver disease in persons who are coinfected with HIV and HCV. This has important implications for timely diagnosis and consideration of treatment in coinfected persons.

Background & Aims: After liver transplantation for hepatitis C virus (HCV), reinfection of the allograft invariably occurs. Indirect evidence suggests that the cellular immune response may play a central role. The purpose of this analysis was to determine the correlation between HCV-specific peripheral CD4 + T-cell responses and the severity of recurrence after liver transplantation. Methods: Fifty-eight HCV-seropositive patients, including 43 liver transplant recipients with at least 1 year of histological follow-up, were studied. Peripheral blood mononuclear cells (PBMCs) were isolated from fresh heparinized blood and stimulated with either recombinant HCV antigens (core, E2, NS3, NS4, and NS5) or control antigens. Results: Fourteen (40%) of 35 patients with mild or no evidence of histological recurrence within their allografts responded to at least 1 of the HCV antigens. Eleven responded to NS3, 5 to all the nonstructural antigens, and 3 to the HCV core polypeptide alone. In contrast, in the 8 patients with severe HCV recurrence, no proliferation in response to any of the HCV antigens was seen ( P = 0.03) despite responses to the control antigens. Conclusions: Despite immunosuppression, HCV-specific, major histocompatibility complex class II–restricted CD4 + T-cell responses are detectable in patients with minimal histological recurrence after liver transplantation. In contrast, PBMCs from patients with severe HCV recurrence, despite being able to proliferate in response to non-HCV antigens, fail to respond to the HCV antigens. These findings suggest that the inability to generate virus-specific T-cell responses plays a contributory role in the pathogenesis of HCV-related graft injury after liver transplantation. It is hoped that further characterization of the immunoregulatory mechanisms related to recurrent HCV will provide the rationale for novel therapeutic strategies and diminish the incidence of inevitable graft loss. GASTROENTEROLOGY 1999;117:926-932

Hepatitis C virus (HCV) is a common infection worldwide, and in most persons, it leads to persistent viremia and liver damage. Efforts to identify the correlates of protective immunity are hampered by this high rate of persistent infection in both infected humans and the only animal model, the chimpanzee. Peripheral blood mononuclear cells from seronegative persons were stimulated with synthetic peptides that represent epitopes recognized by HCV-specific cytotoxic T lymphocytes (CTL) after natural infection. In addition, CD4 + proliferative responses to recombinant HCV proteins were examined in these same persons. CTL responses directed against a peptide epitope of HCV and proliferative responses in 2 HCV-seronegative persons with possible occupational exposure to HCV were found. These otherwise healthy persons were not viremic, suggesting that they may have recovered from acute HCV infection. Characterization of virus-specific immune responses in exposed but seronegative persons may provide important clues as to the nature of protective immunity in HCV.

Although hepatitis C virus (HCV) is a leading cause of morbidity and mortality worldwide, the role of viral cytopathic effects remains unclear. To study the biosynthesis of HCV structural proteins and their pathogenic role, we constructed transgenic mice, expressing type 1b HCV structural proteins (core, E1, and E2) in liver tissues. Two liver-specific promoters were used. The mouse major urinary protein (MUP) promoter has been shown to be developmentally regulated with little or no expression in utero but high-level expression after birth. The albumin (Alb) promoter provides constitutive, high levels of transgenes in live. Expression of both HCV transgenes was detected in several lines by Northern blots, HCV-specific reverse transcriptase-polymerase chain reactions (RT-PCR), and Western immunoblotting. Alb HCV lines showed higher levels of HCV expression than the MUP HCV lines. Immunohistochemical analysis revealed a predominantly cytoplasmic presence of core protein with occasional nuclear staining, and both cytoplasmic and membrane expression of the E2 protein in the transgenic livers. In both transgenes, the highest levels of both antigens were seen in perivenular hepatocytes, suggesting potential processing specificity in those cells. At six months of age, the livers of all transgenic lineages remained histologically normal. We concluded that HCV structural proteins are not directly cytopathic in this animal model.

Based on our CTL studies of over 44 persons with chronic HCV infection, we are able to arrive at a number of conclusions. Clearly this cellular immune response is heterogeneous among infected persons. We have not identified any specific HCV protein which appears to be immunodominant for CTL responses, but rather we have detected diverse responses to both structural and non-structural proteins. Using an identical stimulation strategy for all persons studied, we have been able to detect responses in only approximately one third of persons with chronic infection. Among these persons, the responses among liver-infiltrating lymphocytes are greater than those detected in fresh peripheral blood, suggesting that the CTL are homing to the site of maximal viral burden in these persons. Some viral proteins contain overlapping epitopes presented by more than one HLA class I molecule, and we have also found cases where peptides in the same HLA superfamily, such as the HLA A3 superfamily which contains A11, for which the same peptide can be presented by both alleles (manuscript in preparation). Although sequence variation between the infecting strain and the vaccinia constructs used to test for responses may lead to non-recognition of some variants, even the highly conserved core protein appears to be an inconsistent and actually infrequent target for detectable CTL responses. The magnitude of the CTL response appears to vary greatly, from being undetectable to being so vigorous that it an be detected in stimulated peripheral blood. The breadth of the response also varies widely, ranging from the detection of a response to a single epitope in some persons, to the simultaneous recognition of up to five different epitopes in others. Even in persons of the same HLA type, we have not seen consistent targeting of the same epitopes except in rare cases. Despite the detection of over 20 epitopes and their restricting class I alleles using CTR derived from liver-infiltrating lymphocytes, we have identified only one epitope that has been shown to be targeted by more than one person of the same HLA type. These findings lead us to speculate that the CTL response may be submaximal in the majority of infected persons. The reasons for this are presently obscure, but could relate to a number of factors. The epitopes targeted are found within variable regions of the virus, such that immune escape from established CTL responses has to be considered a real possibility. Sequence variation may also lead to antagonism of CTL responses, as has been demonstrated for both HIV and HBV infections. Furthermore, sequence variation either within or adjacent to regions containing CTL epitopes can lead to altered antigen processing, either due to alteration of proteolytic processing of the viral peptides in the cytoplasm or to altered transport and altered association with class I molecules. A number of issues regarding the CTL response in HCV infection still require substantial attention. The apparent inability of CTL to clear this virus needs to be addressed, as does the potential role for viral immunomodulatory molecules in HCV persistence. Although we and others have shown CTL responses to be present in persons with chronic infection, the role of CTL in acute HCV infection needs to be determined. The best studied chronic human viral infection is HIV infection, in which expanding data indicate that the early events following primary infection predict the subsequent course of illness. Viral load in the first 1-2 years after infection is highly predictive of the subsequent disease course in HIV infection, and recent experimental data in humans suggest that early immune responses may be predictive of subsequent disease course. Such studies in HCV infection have been difficult to achieve, since primary HCV infection is often asymptomatic, and transfusion-related cases are now rare. (ABSTRACT TRUNCATED)

Hepatic CD1d-restricted and natural killer T-cell populations are heterogeneous. Classical 'type 1' α-galactosylceramide-reactive CD1d-restricted T cells express 'invariant' TCRα ('iNKT'). iNKT dominating rodent liver are implicated in inflammation, including in hepatitis models. Low levels of iNKT are detected in human liver, decreased in subjects with chronic hepatitis C (CHC). However, high levels of human hepatic CD161(±) CD56(±) noninvariant pro-inflammatory CD1d-restricted 'type 2' T cells have been identified in vitro. Unlike rodents, healthy human hepatocytes only express trace and intracellular CD1d. Total hepatic CD1d appears to be increased in CHC and primary biliary cirrhosis. Direct ex vivo analysis of human intrahepatic lymphocytes (IHL), including matched ex vivo versus in vitro expanded IHL, demonstrated detectable noninvariant CD1d reactivity in substantial proportions of HCV-positive livers and significant fractions of HCV-negative livers. However, α-galactosylceramide-reactive iNKT were detected only relatively rarely. Liver CD1d-restricted IHL produced IFNγ, variable levels of IL-10 and modest levels of Th2 cytokines IL-4 and IL-13 ex vivo. In a novel FACS assay, a major fraction (10-20%) of hepatic T cells rapidly produced IFNγ and up-regulated activation marker CD69 in response to CD1d. As previously only shown with murine iNKT, noninvariant human CD1d-specific responses were also augmented by IL-12. Interestingly, CD1d was found selectively expressed on the surface of hepatocytes in CHC, but not those CHC subjects with history of alcohol usage or resolved CHC. In contrast to hepatic iNKT, noninvariant IFNγ-producing type 2 CD1d-reactive NKT cells are commonly detected in CHC, together with cognate ligand CD1d, implicating them in CHC liver damage.

Numerous studies of human immunodeficiency virus type 1 (HIV-1)-specific cytotoxic T lymphocytes (CTL) have examined their ability to recognize B-cell lines expressing recombinant HIV-1 proteins, but relatively few data regarding the lysis of HIV-1-infected cells by CTL are available. We studied the ability of HIV-1-specific CTL clones of defined epitope specificity and HLA restriction to lyse infected CD4+ cells at serial time points following infection. CD4+ cell lines were acutely infected with HIV-1 IIIB at a high multiplicity of infection, and the kinetics of cell lysis were examined and compared with the kinetics of viral replication. Intracellular HIV-1 p24 expression was detected by 1 to 2 days after infection, reaching over 98% positive cells by day 4. Recognition of the infected cells by HLA A2- and B14-restricted CTL clones closely paralleled intracellular p24 expression and preceded peak virion production. The maximal levels of lysis with Gag-, reverse transcriptase-, and envelope-specific clones were different, however. The Gag- and envelope-specific clones lysed infected cells at levels equivalent to peptide-sensitized controls, whereas lysis by the reverse transcriptase-specific clones plateaued at a lower level. Peptide titration curves indicated that this effect was not due to differences in sensitivity to the cognate epitopes for the different clones. Although HIV-1 infection induced an approximately 50% decrease in class I HLA expression on the surface of infected cells, lysis by CTL clones was unaffected. These studies indicate that HIV-1-specific CTL can efficiently lyse HIV-1-infected CD4+ cells and suggest that the partial downregulation of class I molecules in infected cells does not significantly affect recognition by CTL.

Cytotoxic T lymphocytes (CTL) are important to the control of viral replication and their presence may be important to disease outcome. An understanding of the spectrum of proteins recognized by hepatitis C virus (HCV)-specific CTL and the functional properties of these cells is an important step in understanding the disease process and the mechanisms of persistent infection, which occurs in the majority of HCV-infected individuals. In this report we identify HCV-specific CTL responses restricted by the HLA class I molecules A2, A3, A11, A23, B7, B8, and B53. The epitopes recognized by these intrahepatic CTL conform to published motifs for binding to HLA class I molecules, although in some cases we have identified CTL epitopes for which no published motif exists. The use of vectors expressing two different strains of HCV, HCV-1 and HCV-H, revealed both strain-specific and cross-reactive CTL. These HCV-specific CTL were shown to produce cytokines including IFN-gamma, TNF-alpha, GM-CSF, IL-8, and IL-10 in an antigen- and HLA class I-specific manner. These studies indicate that the CTL response to HCV is broadly directed and that as many as five different epitopes may be targeted in a single individual. The identification of minimal epitopes may facilitate peptide-specific immunization strategies. In addition, the release of proinflammatory cytokines by these cells may contribute to the pathogenesis of HCV-induced liver damage.

Diabetes mellitus is often identified as an independent risk factor for developing lower respiratory tract infections. Pulmonary infections, such as those caused by Mycobacterum tuberculosis, mucor, Staphylococcus aureus, and gram-negative bacteria may occur with an increased frequency whereas infections due to Streptococcus pneumoniae, Legionella, and influenza may be associated with increased morbidity and mortality. The predisposition to lower respiratory tract infections may represent alterations in pulmonary host defenses at several levels. The purpose of this article is to review the spectrum of pulmonary infections encountered in the diabetic patient, focusing on predisposing defects in pulmonary host defense, highlighting characteristic clinical features, and discussing diagnostic approaches, therapeutic interventions, and prophylaxis in this patient population.

Up to 4 million persons in the USA have chronic hepatitis C (CHC) (1). Despite a decline in overall HCV infections, the number of patients with end stage liver disease due to CHC will increase for the next 2 decades (2). Even with highly effective novel therapies, currently 30–50% of infected individuals fail treatment (3). Therefore, a better understanding of mechanisms involved in CHC-related liver disease progression could permit more efficient therapies. Adaptive effector T cells (frequently assessed by measuring production of prototypic T helper 1 cytokine IFNγ) play an important role in control of HCV infection during the acute phase (4). In CHC, effector HCV-specific T cell immune responses are weak in peripheral blood, although they can be / are present in liver (5–8). It is likely that in chronic infection, persistence of inefficient effector T cell responses causes collateral tissue damage and inflammatory reactions, leading to fibrosis and finally cirrhosis. Regulatory/immunosuppressive T cells (Treg) are apparently involved in HCV pathogenesis, although it remains largely unclear whether they play a detrimental role by suppressing effector T cell responses against HCV or are protective by preventing excessive immunological liver damage. Treg consist of heterogeneous populations that can be natural or induced, antigen-specific or not. Natural Treg, at least in vitro, function via antigen-independent, contact-dependent, and cytokine-independent mechanisms (9), whereas cytokine-mediated suppression (mostly IL-10 and/or TGFβ) has been established for peripheral adaptive Treg in vivo (10). This heterogeneity leads to ambiguous marker(s) for identifying Treg. Current optimal Treg markers are expression of Foxp3, a transcription factor (11), high levels of CD25 (although both of these markers can also be expressed by activated effector T cells), as well as minimal CD127 (IL-7 receptor) expression (12). In HCV infection, increased circulating CD4+CD25+Foxp3+ T cells were associated with viral persistence (13, 14) with suppressive activity independent of cytokines and antigen non-specific (15, 16). Histological co-staining of liver infiltrates showed CD4+Foxp3+ cells at high proportion in livers of CHC patients (17), suggesting their involvement in intrahepatic immune regulation, but possibly also amelioration of fibrosis (18). HCV can prime virus-specific CD4+CD25+Foxp3+ Treg with antigen-specific expansion and suppression of HCV-specific CD8+ T cells (19). Treg also include IL-10-producing CD4+ HCV-specific T cells (20), and IL-10 dampens hepatic inflammation, but also leads to increased viral load (21). Peripheral CD4+CD25+ Treg were shown to secrete TGFβ in response to HCV, which was inversely correlated with liver inflammation (22). Suppressive IL-10 producing HCV-specific CD8+ liver infiltrating lymphocytes were also described (23) and have been associated with protection against apoptosis and fibrosis-related laminin production, as CD8 T cells were located in liver areas with both low hepatocyte apoptosis and fibrosis (24). A limitation of previous studies on Treg is use of phenotypic markers to characterize Treg before functional analysis, as opposed to functionally defining relevant Treg first, so as to not miss subsets. We identified in CHC novel blood HCV-specific CD8+CD25-Foxp3- Treg secreting TGFβ, first functionally then phenotypically (25). TGFβ production by CD4+ T cells was also observed in one patient. Suppression of peripheral HCV-specific IFNγ was predominantly mediated by TGFβ rather than IL-10. Presence of HCV-specific CD4 and CD8 T cells producing TGFβ was recently confirmed in PBMC in acute HCV infection (37). Of note, TGFβ is a multi-functional cytokine with unique ability to direct T cell lineage commitment toward either pro-inflammatory Th17 T cells or anti-inflammatory Treg, depending on presence of additional factors, such as IL-6 (26). Significantly, TGFβ is also a key cytokine driving liver fibrogenesis (27). Disruption of the local balance between opposing effects of TGFβ on liver inflammation and fibrogenesis could underline fibrosis progression in CHC. Here we found that TGFβ produced by HCV specific T cells significantly masks T cell effector response only in those patients that show attenuated fibrosis progression. In addition, TGFβ inversely correlated not only with liver inflammation, but also with liver fibrosis progression and fibrogenic HSC gene expression. It is possible that in chronic HCV infection immunoregulatory and anti-inflammatory functions of TGFβ, produced by certain HCV-specific Treg, ameliorate liver inflammation, whilst limiting the fibrotic process.

Coinfection with hepatitis C (HCV) significantly increases the risk of acute and chronic renal disease in HIV-infected individuals. However, the burden of acute kidney injury (AKI) directly attributable to HIV among HCV-infected individuals and associated risk factors are not well understood. Within a prospective cohort, AKI episodes were identified by a rise in creatinine of 0.5 mg/dL. Incidence of first AKI events was calculated for HIV/HCV coinfected versus HCV monoinfected subjects, and multivariable analyses using Cox proportional hazards were performed to identify predictors of AKI. Throughout the study period, 35% HIV/HCV coinfected and 17% HCV monoinfected subjects developed AKI, with incidence of 8.74/100 person-years and 3.53/100 person-years, respectively (hazard ratio (HR) 2.48; [95% confidence interval (CI) 1.50, 3.74]). In multivariable analysis, HIV coinfection (HR 2.19 [1.33, 3.62]), decompensated cirrhosis (HR 6.64 [3.81, 11.6]), and cocaine use (HR 2.06 [1.15, 3.71]) were independently associated with AKI. HCV genotype, HCV viral load, hazardous drinking, and heroin use were not associated with AKI. Study limitations included potential misclassification bias of HCV-infected individuals as serial HIV antibody testing was not routinely performed after study entry, and inability to adjust for tenofovir use in multivariable analysis. In conclusion, among subjects with HCV infection, decompensated cirrhosis, HIV coinfection, and cocaine use are associated with increased risk of AKI. These findings highlight the importance of preventing and treating cirrhosis, controlling HIV coinfection, and reducing cocaine use in HIV/HCV coinfected persons.

We evaluated immunologic predictors of response to HBV vaccine administered in the presence or absence of GM-CSF in HIV infected individuals. We measured peripheral blood hematopoietic progenitor, monocyte and myeloid-derived suppressor cell (MDSC) frequencies, and expression of GMCSF receptor on monocytes and MDSCs, at baseline and 4 weeks after immunization in relation to antibody response. We observed higher baseline progenitor and lower monocyte frequencies among week 16 antibody responders. Week 4 decline in MDSC frequency was associated with week 16 antibody response, while administration of GM-CSF was associated with preservation of these cells. No significant differences in GM-CSF receptor expression were observed in the presence vs. absence of GM-CSF. These findings are consistent with a positive role of progenitor cells and a potential negative role of monocytes in vaccine response. Additionally, GM-CSF augmented the preservation of peripheral blood MDSC, which may contribute to the lack of improved vaccine responses.

Hepatitis C virus (HCV) is a major cause of posttransfusion and community-acquired hepatitis, and a majority of individuals infected with this virus will subsequently develop chronic hepatitis. Characterization of the host immune response to this infection is an important first step that should facilitate the development of immunomodulatory agents and vaccines. Cellular immune responses, especially those mediated by cytotoxic T lymphocytes (CTL), are important in the control of many viral diseases. In this study, liver-infiltrating lymphocytes from persons with chronic HCV hepatitis were examined for evidence of HCV-specific CTL by using target cells infected with recombinant vaccinia viruses expressing the HCV core, E1, E2, and part of the NS2 proteins. Bulk expansion of liver-derived CD8+ lymphocytes resulted in the detection of HCV-specific CTL activity, whereas activity could not be found in CD8+ lymphocytes expanded from peripheral blood. Epitopes recognized by these CTL were defined by using CTL clones obtained by limiting dilution and target cells sensitized with synthetic HCV peptides. Four distinct HLA class I-restricted epitopes were identified, including two epitopes in the amino-terminal portion of the core protein. These studies provide evidence that the highly conserved core protein is a target for HCV-specific CTL and identify CTL epitopes within the more highly variable E2 envelope protein. Our studies also suggest that HCV-specific CTL are localized at the site of tissue injury in infected persons with chronic hepatitis. Identification of the epitopes recognized by HCV-specific CTL will facilitate exploration of their role in disease pathogenesis and may provide information useful in development of therapeutic interventions or vaccines.

Background: Hepatitis C virus (HCV)/HIV coinfection treatment is suboptimal with low sustained viral response rates to standard therapies. A multicenter randomized clinical trial designed to assess the efficacy/safety of pegylated interferon maintenance therapy was performed by the National Institutes of Health-funded AIDS Clinical Trials Group network. Methods: HCV treatment-naive and nonresponding interferon-experienced subjects with confirmed HCV and HIV, CD4 >200 cells per cubic millimeter, and at least stage 1 fibrosis were enrolled and treated for 12 weeks with pegylated interferon alfa 2a 180 mcg per week (PEG) + weight-based ribavirin to determine response status. Nonresponder subjects (failure to clear HCV RNA or achieve 2-log drop) underwent liver biopsy and were randomized to receive full dose PEG or observation only for 72 weeks. Paired biopsies were evaluated by a central pathologist. Results: Three hundred thirty subjects were enrolled; median age was 48 years; 43% white, 37% black, non-Hispanic; 83% male; CD4+ 498 cells per cubic millimeter; 32% were interferon experienced; 74% had entry HIV RNA

Noninvasive markers of liver fibrosis correlate with the stage of liver fibrosis, but have not been widely applied to predict liver-related mortality.We assessed the ability of two indices of liver fibrosis, aspartate aminotransferase (AST)-to-platelet ratio index (APRI) and Fib-4, and two markers of extracellular matrix metabolism, hyaluronic acid (HA) and YKL40, to predict liver mortality in a prospective cohort of hepatitis C virus (HCV)-infected individuals with and without HIV coinfection. These were compared with two established prognostic scores, the Child-Pugh-Turcotte (CPT) and model of end-stage liver disease (MELD) scores.A total of 303 subjects, of whom 207 were HIV positive at study entry, were followed up for a mean period of 3.1 years. There were 33 deaths due to liver disease. The ability of each test and score to predict 3-year liver mortality was expressed as the area under the receiver operator curve. The area under the receiver operator curve 95% confidence intervals were: HA 0.92 (0.86-0.96), CPT 0.91 (0.79-0.96), APRI 0.88 (0.80-0.93), Fib-4 0.87 (0.77-0.92), MELD 0.84 (71-0.91). In multivariate analyses HA, APRI, and fib-4 were independent predictors of mortality when included in models with MELD or CPT.Noninvasive markers of liver fibrosis are highly predictive of liver outcome in HCV-infected individuals with and without HIV coinfection. These markers seem to have a prognostic value independent of CPT and MELD.

An increasing number of antiviral agents are presently in various stages of development and testing, and an increasing number have recently been licensed for use in humans. These drugs have been used extensively to treat viral infections in immunocompromised individuals, and these studies indicate that for many antiviral agents the response to therapy is highly dependent on the integrity of the underlying host immune response. In particular, the response to zidovudine, acyclovir and ganciclovir in persons with HIV-1 infection is highly dependent upon CD4 number, which can be considered a surrogate marker for the state of host immune function in these subjects. Responses to interferons likewise can be shown to depend on the host immune response, with responses due to both direct antiviral effects of this agent as well as immunomodulatory effects mediated through interferon-induced upregulation of HLA molecule expression. The interdependence of host immunity with antiviral efficacy is underscored by the increased antiviral drug resistance in persons with advanced degrees of chronic immunosuppression, related to the higher level of viral replication and viraemia which occurs in the absence of an effective host immune response. Further definition of the precise mechanisms of these interactions should facilitate the rational design of antiviral agents and immunomodulatory therapies to improve treatment of viral infections.

Important questions remain on the role of T cells in progression of hepatitis virus-mediated liver pathogenesis: are T cells 'Good or Bad'? How could one maintain a beneficial balance, in which regulatory T-cell (Treg) populations might play an important role? Treg are a heterogeneous population of cells, including the classical CD4+CD25+ subset expressing the transcription factor Foxp3, CD4 T cells secreting IL-10 (Tr1) or TGF-beta (Th3), but also some CD8 T cells, double negative T cells and gammadelta T cells. The role of Treg in viral hepatitis, particularly HBV and HCV, seems to range from suppressing T-cell responses directed against hepatitis viruses to down-regulating the immune responses causing the liver damage. Questions also remain unresolved on which Treg populations are important and how to establish a beneficial balance, mostly due to the difficulties in studying the heterogeneous Treg populations but also due to the problem accessing liver, the principal target of hepatitis viruses. Here, we will review progress to date on understanding Treg populations in regard to viral hepatitis.

Co-infection with human immunodeficiency virus (HIV) is associated with reduced hepatitis C virus (HCV) treatment response and accelerated HCV disease. Cytokines, as mediators of immune responses, inflammation, and fibrogenesis, may underlie important differences in HCV pathogenesis during HIV co-infection. We previously found that serum interleukin-8 (IL-8) and tumor necrosis factor-alpha (TNF-alpha) increased after HCV therapy with interferon (IFN) in HCV/HIV co-infected patients; however, cytokine levels were not predictive of HCV therapeutic response. Here, we examined viral factors associated with expression of IL-8, TNF-alpha, and transforming growth factor-beta1 (TGF-beta1) in uninfected, HCV mono-infected, HIV mono-infected, and HCV/HIV co-infected persons. HIV co-infection was associated with decreased IL-8 detection but not TNF-alpha detection. A significant interaction effect demonstrated that HIV infection was associated with elevated TGF-beta1 in HCV-positive individuals but not in HCV-negative individuals. The induction of a sustained profibrotic signal, such as TGF-beta1, by HIV may cause accelerated liver fibrosis during HCV/HIV co-infection and may hinder the host's ability to mount an effective HCV-specific immune response. Further studies are warranted to identify noninvasive markers of liver disease for the clinical management of HCV disease, particularly when liver biopsies have not been performed or are contraindicated.

Hepatitis C virus (HCV)-specific T-cell responses are rarely detected in peripheral blood, especially in the presence of human immunodeficiency virus (HIV) coinfection. Based on recent evidence that T-regulatory cells may be increased in chronic HCV, we hypothesized that functional blockade of regulatory cells could raise HCV-specific responses and might be differentially regulated in the setting of HIV coinfection. Three groups of subjects were studied: HCV monoinfected, HCV-HIV coinfected, and healthy controls. Frequencies of peripheral T cells specific for peptides derived from HCV core, HIV type 1 p24, and recall antigens were analyzed by gamma interferon (IFN-γ) enzyme-linked immunospot assay. HCV-specific T-cell responses were very weak in groups with HCV and HCV-HIV infections. Addition of blocking antibodies against transforming growth factor β1 (TGF-β1), -2, and -3 and interleukin-10 specifically increased the HCV-specific T-cell responses in both infected groups; however, this increase was attenuated in the group with HCV-HIV coinfection compared to HCV infection alone. No increase in recall antigen- or HIV-specific responses was observed. Flow cytometric sorter analysis demonstrated that regulatory-associated cytokines were produced by HCV-specific CD3+CD8+CD25−cells. Enhancement of the IFN-γ effect was observed for both CD4 and CD8 T cells and was mediated primarily by TGF-β1, -2, and -3 neutralization. In conclusion, blockade of TGF-β secretion could enhance peripheral HCV-specific T-cell responses even in the presence of HIV coinfection.