Comparison of HCV-specific intrahepatic CD4+ T cells in HIV/HCV versus HCV

PROFILE OF HCV GENOTYPES AND HIV-SUBTYPES AMONG HIV-COINFECTED PATIENTS IN SOUTHERN BRAZIL

BACKGROUND

Hepatitis B and C virus (HBV and HCV) are the two most common infections among human immunodeficiency virus (HIV)-infected patients.

OBJECTIVE

To identify the frequency of HIV subtypes and HCV genotypes in HIV-coinfected patients.

METHODS

A cross-sectional and retrospective study was carried out into two reference centers in Southern Brazil between January 1, 2002 and June 30, 2016. The Abbott Real Time HCV Genotype II system was used for routine diagnostics to determine the HCV genotype based on dual-target real-time PCR. Proviral HIV-1 RNA was extracted from serum samples and fragments of the pol gene were generated by PCR. The HIV-1 PT and RT gene sequences were submitted to Maximum Likelihood Phylogenetic analysis by collecting reference sequences from the HIV-1 group M subtype of the Los Alamos database.

RESULTS

During the study period, 3340 patients with HIV were diagnosed at both referral centers, of which 4.97% (166/3340) had HBV and/or HCV coinfection. Seroprevalence of HIV-HBV, HIV-HCV and HIV-HBV-HCV was 37.4%, 58.4%, and 4.2%, respectively. HIV-HCV-coinfected patients had a lower median nadir CD4+ T-cell count when compared to HIV-HBV-coinfected patients (P=0.01). Among those coinfected with HCV, HCV-1 (HCV-1) and HCV-3 (HCV-3) genotypes were the most prevalent, being detected in 73.8% and 21.4%, respectively. Among the HCV-1 coinfected patients, 79.3% and 20.1% had subtypes 1a and 1b, respectively. HIV subtype B was the most prevalent in HIV-coinfected patients. There was no significant difference regarding nadir CD4+ T-cell count and HIV viral load when compared to coinfected with HCV-1 with HCV-3, as well as those co-infected with HCV-1a with HCV-1b.

CONCLUSION

In the present study, a higher frequency of subtype B of HIV and HCV-1 were found in HIV-coinfected patients. Further larger-scale and long-term studies are needed to better understand the effect of HCV genotypes in HIV-infected patients.

Seroprevalence of hepatitis B virus (HBV) and hepatitis C virus (HCV) among human immunodeficiency virus (HIV)-infected patients in an HBV endemic area in Brazil

Background

Hepatitis B virus (HBV) and hepatitis C virus (HCV) are a common cause of complications in liver disease and immunological impairment among human immunodeficiency virus (HIV)-infected patients. The aim of this study was to assess the seroprevalence of HBV and HCV and their correlation with CD4+ T-cells among HIV-infected patients in an HBV endemic area.

Methods

A cross-sectional observational and retrospective study was carried out in a reference center in Southern Brazil between January 2005 and December 2016. Socio-demographic data were collected by using a structured questionnaire. Serological tests and analysis of CD4+ T-cell count levels were performed using standard procedures.

Results

The seroprevalence of HIV-HBV, HIV-HCV, and HIV-HBV-HCV coinfections was 3.10%, 3.10%, and 0.16%, respectively. At baseline, anti-hepatitis B surface and anti-hepatitis B core antigens were detected in 46.27% and 16.74% of HIV-monoinfected patients and in 31.25% and 21.86% of the HIV-HCV coinfected patients, respectively. The median CD4+ T-cell count at baseline in the HIV-monoinfected group was higher than that in the HIV-coinfected groups, but without statistical significance. The median CD4+ T-cell count and the CD4/CD8 ratio were significantly higher in HIV-HBV and HIV-HCV groups after 24 months of combination antiretroviral therapy (cART) compared to the pre-cART values. When comparing patients with HIV-HBV and HIV-HCV on cART, CD4+ T-cell recovery was more rapid for HIV-HBV patients.

Conclusion

Although the analyzed region was endemic for HBV, the prevalence of HIV-HBV and HIV-HCV coinfection was lower than the rate found in the general population of Brazil. HBV and HCV had no significant impact on CD4+ T-cell counts among HIV-infected patients at baseline.

Hepatitis in AIDS patients

The individuals with HIV infection are more susceptible to develop coinfections with infectious pathogens such as HCV and HBV. The routes of transmission of these pathogens are the same including sexual contact, injection drug use, or at birth from mother to an infant. The main reason of morbidity and mortality in HIV infected individuals is a liver disease in the context of antiretroviral therapy, and coinfection such as HCV and HBV complicates this condition. Nucleos(t)ide analogues are used for HBV infection management, and treatment of HCV infection is done by PegIFN and ribavirin combination and protease inhibitors. In this review, we focused on hepatitis B and C infections in HIV patients along with their therapies.

Liver involvement in human immunodeficiency virus infection

The advances in management of patients with acquired immunodeficiency syndrome (AIDS) with highly effective anti-retroviral therapy (HAART) have resulted in increased longevity of patients with human immunodeficiency virus (HIV) infection. AIDS-related illnesses now account for less than 50 % of the deaths, and liver diseases have emerged as the leading cause of death in patients with HIV infection. Chronic viral hepatitis, drug-related hepatotoxicity, non-alcoholic fatty liver disease, and opportunistic infections are the common liver diseases that are seen in HIV-infected individuals. Because of the shared routes of transmission, co-infections with hepatitis B virus (HBV) and hepatitis C virus (HCV) are very common in HIV-infected persons. Hepatitis C is the most common viral hepatitis seen in HIV-infected patients. With the availability of directly acting agents, treatment outcome of HCV is comparable to that seen in non HIV-infected patients. Careful monitoring is required for drug interactions and drug-induced hepatotoxicity and modification of drugs should be done where necessary. The results of liver transplantation in select HIV-infected patients can be comparable with those of HIV-negative patients.

Immunopathogenesis of Hepatitis C Virus Infection

Despite advances in therapy, hepatitis C virus infection remains a major global health issue with 3 to 4 million incident cases and 170 million prevalent chronic infections. Complex, partially understood, host-virus interactions determine whether an acute infection with hepatitis C resolves, as occurs in approximately 30% of cases, or generates a persistent hepatic infection, as occurs in the remainder. Once chronic infection is established, the velocity of hepatocyte injury and resultant fibrosis is significantly modulated by immunologic as well as environmental factors. Immunomodulation has been the backbone of antiviral therapy despite poor understanding of its mechanism of action.

Role of liver transplantation in human immunodeficiency virus positive patients

End-stage liver disease (ESLD) is a leading cause of morbidity and mortality amongst human immunodeficiency virus (HIV)-positive individuals. Chronic hepatitis B and hepatitis C virus (HCV) infection, drug-induced hepatotoxicity related to combined anti-retro-viral therapy, alcohol related liver disease and non-alcohol related fatty liver disease appear to be the leading causes. It is therefore, anticipated that more HIV-positive patients with ESLD will present as potential transplant candidates. HIV infection is no longer a contraindication to liver transplantation. Key transplantation outcomes such as rejection and infection rates as well as medium term graft and patient survival match those seen in the non-HIV infected patients in the absence of co-existing HCV infection. HIV disease does not seem to be negatively impacted by transplantation. However, HIV-HCV co-infection transplant outcomes remain suboptimal due to recurrence. In this article, we review the key challenges faced by this patient cohort in the pre- and post-transplant period.

Do the epidemiology, physiological mechanisms and characteristics of hepatocellular carcinoma in HIV-infected patients justify specific screening policies?

Reducing the incidence of hepatocellular carcinoma (HCC) in HIV-infected patients has become a serious problem when managing these patients. There are many explanations for this disease evolution, which notably include their longer survival under effective antiviral therapy and also the more rapid evolution of chronic liver disease. Despite recent advances in the management of hepatitis B (HBV) and hepatitis C (HCV) viral diseases, which will probably increase the number of patients achieving a virological response, HIV-infected patients with cirrhosis are still at risk of the onset of HCC. This evolution to HCC is also correlated to other comorbidities such as excessive alcohol consumption and nonalcoholic steatohepatitis (NASH). HCC thus remains a public health issue in this population. The poor prognosis and aggressiveness of HCC have been fully demonstrated, but the mechanisms underlying this aggressiveness are not yet well defined. As well as underlying mechanisms that contribute to accelerating hepatocarcinogenesis in HIV-infected patients, there are other reasons why HIV-infected patients should be considered a higher risk population. This review discusses the principal epidemiological determinants; the mechanisms of pathogenesis; and the treatment of HCC in HIV/HBV and HIV/HCV coinfected patients. It also discusses the probable need to develop a specific screening policy for HCC in this population in order to prevent the rapid development and to make them more amenable to a curative treatment.

Hepatitis C virus infection in patients with HIV-1: epidemiology, natural history and management

Hepatitis C virus (HCV)-related liver diseases have contributed to increased morbidity and mortality in HIV-1-infected individuals in the era of effective antiretroviral therapy. HCV transmission patterns have changed among the HIV co-infected population during the last decade, with acute HCV infection emerging worldwide. HIV infection accelerates the progression of HCV-related liver diseases and consequently cirrhosis, liver failure, and hepatocellular carcinoma. However, the current standard treatment of HCV infection with pegylated interferon plus ribavirin results in only a limited viral response. Furthermore, cumbersome pill regimens, antiretroviral related hepatotoxicity, and drug interactions of HCV and HIV regimens complicate therapy strategies. Fortunately, in the near future, new direct-acting anti-HCV agents will widen therapeutic options for HCV/HIV co-infection. Liver transplantation is also gradually accepted as a therapeutic option for end stage liver disease of HCV/HIV co-infected patients.

Characterization of CD4⁺ T-cell immune activation and interleukin 10 levels among HIV, hepatitis C virus, and HIV/HCV-coinfected patients

BACKGROUND

HIV/hepatitis C virus (HCV)-coinfected patients have accelerated liver disease compared with HCV monoinfection. In HIV-positive patients with viral suppression, data comparing inflammatory cytokines and immune activation between HIV/HCV coinfection with chronic hepatitis C (CHC) to HIV/HCV-seropositive patients with cleared HCV are limited.

METHODS

Fifty-nine age- and sex-matched patients were stratified: (1) HIV monoinfection (n = 15); (2) HCV monoinfection with CHC (n = 15); (3) HIV/HCV coinfection with CHC (n = 14); and (4) HIV/HCV seropositive with cleared HCV (n = 15). All HIV-positive patients had undetectable HIV viremia, and median CD4 was 420 cells per microliter. Liver fibrosis was assessed in each subject using transient elastography. Cells were collected for CD4 and CD8 immune activation (CD38/HLA-DR) markers via flow cytometry and plasma for luminex-multiplex cytokine assays.

RESULTS

CD38⁺HLA-DR⁺ expression on CD4⁺ T cells was significantly increased in HIV/HCV coinfection with CHC (7%) versus HCV monoinfection (4%) (P = 0.012). CD4⁺ total HLA-DR⁺ expression was significantly increased in HIV/HCV coinfection with CHC (43%) versus HIV monoinfection (31%) (P = 0.010) and HIV/HCV seropositive with cleared HCV (38%) (P = 0.046). Total CD4⁺CD38⁺ and CD4⁺CD38⁺HLA-DR⁻ expression was significantly higher in HIV monoinfection (23% and 18%) than HCV moninfection (13%, P = 0.002% and 9%, P = 0.001, respectively). Interleukin 10 levels were significantly lower in HIV monoinfection versus HIV/HCV coinfection with CHC (P = 0.0002). In multivariate analysis, severe fibrosis was associated with lower expression of CD4⁺CD38⁺HLA-DR⁺ and CD4⁺ total CD38⁺ than mild-moderate fibrosis (P = 0.03 and 0.03, respectively).

CONCLUSIONS

CD4 immune activation with HLA-DR⁺ expression in HIV/HCV coinfection with well-controlled HIV may arise from chronic HCV viremia. Conversely, CD4⁺CD38⁺ expression may be driven by underlying HIV infection. CD4 immune activation was unexpectedly found to be associated with decreased liver fibrosis.

Characteristics of the cellular immune response in HIV/HCV patients with hemophilia during peginterferon/ribavirin therapy in southern China

OBJECTIVE

The objectives of the study are to characterize the cellular immune response in hepatitis C virus (HCV) genotype 1 and HIV co-infected patients with hemophilia in southern China during treatment with interferon and ribavirin and to study its correlation with the virologic response (VR). Thirty-six HCV genotype 1 and HIV co-infected patients with hemophilia in southern China were enrolled into the study. Using an ELISpot assay, HCV antigen-specific interferon (IFN) γ, interleukin (IL) 2, IL-4, and IL-10 secreting cells were measured in peripheral blood mononuclear cells. Single nucleotide polymorphisms of IL28B were determined, and immunological, virologic, and clinical variables were collected to identify factors associated with HCV-sustained VR (SVR) at week 72 after treatment. At baseline, there were no significant differences in IFN-γ and IL-2 mediated immune responses in subjects with VR versus non-responders. Higher IL-10 specific responses to NS3 were observed in VR patients. Subjects who had significant decreases in IL-10 responses at week 72 compared with baseline for NS3 and NS5 were more likely to be VR. In SVR, IL-2 production decreased moderately, and the levels of IL-4 were low throughout. The main correlation for SVR in genotype-l infected subjects was sustained HCV-specific IFN-γ responses through the whole 72-week period. In subjects with HIV and HCV co-infection combined with hemophilia, IL28B genotype CC, a decrease in HCV specific IL-l0 and IL-2 responses, and the maintenance of IFN-γ responses during treatment were associated with a 12- or 72-week VR.

Expression of inhibitory markers is increased on effector memory T cells during hepatitis C virus/HIV coinfection as compared to hepatitis C virus or HIV monoinfection

OBJECTIVE

Hepatitis C virus (HCV)/HIV coinfection is associated with rapid progression of hepatic fibrosis and liver disease. T-cell response has been implicated in the pathophysiological outcome of the disease.

DESIGN

This study sought to evaluate the role of memory T-cell exhaustion in enhancing immune dysfunction during coinfection.

METHODS

Sixty-four patients were included in the study; HCV monoinfected (n = 21), HIV monoinfected (n = 23), HCV/HIV coinfected (n = 20), and healthy controls (n = 20). Peripheral blood mononuclear cells (PBMCs) were isolated; immunophenotyped and functional assays were performed.

RESULTS

A significant increase in the naive T cells and central memory T cells and a marked reduction in effector memory T cells (TEM) were observed with coinfection as compared to monoinfection. Inhibitory markers programmed death 1 (PD-1) and T-cell immunoglobulin and mucin domain containing molecule 3 (TIM3) were highly upregulated on TEM in coinfection and functionally, these TEM cells displayed lowered proliferation. Increased expression of PD-1 and TIM3 correlated with decreased levels of CD8+CD107a+ TEM cells in coinfection. Pro-inflammatory cytokines interferon-γ and interleukin-2 (IL-2) secretion by TEM cells were also reduced during chronic viral infection. Secretion of IL-10, a human cytokine synthesis inhibitory factor, was significantly upregulated in CD4 TEM with HCV/HIV coinfection in comparison to HCV monoinfection.

CONCLUSION

TEM cells play an important role during viral infection and enhanced expression of inhibitory markers is associated with decreased proliferation and cytotoxicity and increased IL-10 production, which was pronounced in HCV/HIV coinfection. Thus, decreased TEM functionality contributes to diminished host immune responses during HCV/HIV coinfection as compared to HCV or HIV monoinfection.

Human immunodeficiency virus, hepatitis C, and inflammatory biomarkers in individuals with alcohol problems: a cross-sectional study

Background

Assessing whether hepatitis C (HCV) co-infection with human immunodeficiency virus (HIV) is associated with increased inflammation is complex. The liver, integral to inflammatory biomarker synthesis, is compromised by HCV and alcohol abuse. Using single liver-synthesized biomarkers (e.g. C-reactive protein) to represent inflammation may not be appropriate in HIV/HCV co-infection. We hypothesized that 1) detectable HIV/HCV RNA was independently associated with increased inflammation; 2) a composite inflammation measure describes inflammation differently from single inflammatory biomarkers.

Methods

We compared inflammation by HIV/HCV group in a cohort of 361 HIV infected participants from the HIV-Longitudinal Interrelationships of Viruses and Ethanol study. Inflammatory biomarkers >75th percentile were considered elevated. Associations between HIV/HCV group and elevated biomarkers were analyzed as a composite measure (inflammatory burden) or individually. We defined inflammatory burden as number of concurrently elevated biomarkers. Biomarkers included interleukin-6 (IL-6), C-reactive protein (CRP), cystatin C, serum amyloid-A (SAA), tumor necrosis factor-alpha (TNF-α), interleukin-10 (IL-10). Covariates: alcohol, liver fibrosis, comorbidities, CD4 count, antiretroviral therapy, substance use.

Results

Detectable HIV and HCV RNA (OR = 2.49; 95% CI = 1.05–5.89) and detectable HCV RNA alone (2.95; 1.08–8.01) were independently associated with increased odds of having a greater inflammatory burden compared to undetectable viremia. Elevated IL-10 (7.79; 1.90–31.97) and TNF-α (7.70; 1.42–41.83) were independently associated with detectable HIV and HCV RNA. Elevated IL-10 was also associated with detectable HCV RNA alone (5.51; 1.17, 25.84).

Conclusions

Detectable HIV and HCV replication versus undetectable replication was associated with inflammatory burden and certain inflammatory biomarkers independently of alcohol consumption, liver fibrosis and other comorbidities.

Incidence of hepatitis C virus infection among Egyptian healthcare workers at high risk of infection

BACKGROUND

Hepatitis C virus (HCV) is a global health threat with Egypt having the highest worldwide prevalence. Evaluation of the efficacy of a preventive HCV vaccine, such as those currently in Phase I/II trials, requires a cohort with a high-risk exposure to HCV.

OBJECTIVE

To identify a reliable cohort for evaluating preventive HCV vaccines, we studied HCV incidence among HCW in a hospital where almost 85% of patients are HCV-infected.

STUDY DESIGN

Of 717 HCW negative for HCV-antibodies (anti-HCV) at baseline, 651 were followed up and tested for seroconversion twice annually for an average of 504 ± 154 days. Those reporting a needle-stick injury were additionally tested for both HCV antibodies and RNA monthly for a total of four months.

RESULTS

Two subjects (0.31%) had anti-HCV and HCV-RNA seroconversion with an overall incidence of 2.04/1000 person-years and a 4.8% incidence among the 21 subjects who reported a needle-stick injury. Two additional subjects had viremia without detectable anti-HCV. Two of the four subjects were among 21 with reported needle-stick injuries (9.5%) and another had surgery. All four were nurses providing direct patient care.

CONCLUSIONS

Our results show that both transient and persistent viremia were detectable in this high-risk cohort of HCW and suggest that absence of anti-HCV in two of the subjects may be due to low-dose viral exposures. These data indicate that HCV infections acquired from documented injuries during direct patient care are frequent in Egypt and can guide selection of eligible HCW suitable for preventive HCV vaccine trials.

Challenges for HCV vaccine development in HIV-HCV coinfection

It is estimated that 4-5 million HIV-infected patients are coinfected with HCV. The impact of HIV on the natural course of HCV infection is deleterious. This includes a higher rate of HCV persistence and a faster rate of fibrosis progression. Coinfected patients show poor treatment outcome following standard HCV therapy. Although direct antiviral agents offer new therapeutic options, their use is hindered by potential drug interactions and toxicity in HIV-infected patients under HAART. Overtime, a large reservoir of HCV genotype 1 patients will accumulate in resource poor countries where the hepatitis C treatment is not easily affordable and HIV therapy remains the primary health issue for coinfected individuals. HCV vaccines represent a promising strategy as an adjunct or alternative to current HCV therapy. Here, the authors review the pathogenesis of hepatitis C in HIV-infected patients, with a focus on the impact of HIV on HCV-specific immune responses and discuss the challenges for vaccine development in HIV-HCV coinfection.

Hepatitis C virus-multispecific T-cell responses without viremia or seroconversion among Egyptian health care workers at high risk of infection

Hepatitis C virus (HCV)-specific cell-mediated immunity (CMI) has been reported among exposed individuals without viremia or seroconversion. Limited data are available regarding CMI among at-risk, seronegative, aviremic Egyptian health care workers (HCW), where HCV genotype 4 predominates. We investigated CMI responses among HCW at the National Liver Institute, where over 85% of the patients are HCV infected. We quantified HCV-specific CMI in 52 seronegative aviremic Egyptian HCW using a gamma interferon (IFN-γ) enzyme-linked immunospot assay in response to 7 HCV genotype 4a overlapping 15-mer peptide pools covering most of the viral genome. A positive HCV-specific IFN-γ response was detected in 29 of 52 HCW (55.8%), where 21 (40.4%) had a positive response for two to seven HCV pools and 8 (15.4%) responded to only one pool. The average numbers of IFN-γ total spot-forming cells (SFC) per million peripheral blood mononuclear cells (PBMC) (± standard error of the mean [SEM]) in the 29 responding and 23 nonresponding HCW were 842 ± 141 and 64 ± 15, respectively (P < 0.001). Flow cytometry indicated that both CD4(+) and CD4(-) T cells produced IFN-γ. In summary, more than half of Egyptian HCW demonstrated strong HCV multispecific CMI without viremia or seroconversion, suggesting possible clearance of low HCV exposure(s). These data suggest that detecting anti-HCV and viremia to determine past exposure to HCV can lead to an underestimation of the true disease exposure and that CMI response may contribute to the low degree of chronic HCV infection in these HCW. These findings could have strong implications for planning vaccine studies among populations with a high HCV exposure rate. Further studies are needed to determine whether these responses are protective.

Immunopathogenesis of HIV/hepatitis C virus coinfection

As a result of shared infection routes, approximately 25% of individuals infected with HIV in North America are also infected with hepatitis C virus (HCV). In the setting of HIV coinfection, the course of HCV disease is more aggressive, resulting in higher HCV viral loads and a more rapid progression of liver pathology. With the success of HAART, HCV-related end-stage liver disease has become a leading cause of morbidity and mortality in HIV/HCV-coinfected patients. In this article, we will discuss recent studies examining the immune response during HIV and HCV coinfection, focusing on alterations or dysfunctions in virus-specific T-cell responses that may play a role in the immunopathogenesis of HIV/HCV coinfection. Summarizing the impact of HIV coinfection on HCV-specific T-cell immunity and highlighting some of the proposed mechanisms of T-cell dysfunction in HIV/HCV-coinfected individuals may uncover information that could lead to new treatment strategies for these patients experiencing accelerated liver disease and generally poorer outcomes than their HCV-monoinfected counterparts.

Liver transplantation in human immunodeficiency virus-positive patients

With the successful introduction of combined antiretroviral therapy (cART), human immunodeficiency virus (HIV) is now regarded as a chronic illness with excellent long-term outcomes. However, chronic exposure to viral etiologies (ie, chronic hepatitis B and hepatitis C) and drug-induced toxicity secondary to cART have resulted in increasing rates of mortality and morbidity due to end-stage liver disease. HIV disease is no longer considered an absolute contraindication to liver transplantation (LT) by most transplant centers worldwide. Because the burden of liver disease in this cohort is likely to increase, this review addresses the key etiologies and the management strategies available for HIV-positive patients undergoing LT.

Increasing burden of liver disease in patients with HIV infection

Introduction of effective combined antiretroviral therapy has made HIV infection a chronic illness. Substantial reductions in the number of AIDS-related deaths have been accompanied by an increase in liver-related morbidity and mortality due to co-infection with chronic hepatitis B and C viruses. Increases in non-alcoholic fatty liver disease and drug-induced hepatotoxicity, together with development of hepatocellular carcinoma, also potentiate the burden of liver disease in individuals with HIV infection. We provide an overview of the key causes, disease mechanisms of pathogenesis, and recommendations for treatment options including the evolving role of liver transplantation.

Strong hepatitis C virus (HCV)-specific cell-mediated immune responses in the absence of viremia or antibodies among uninfected siblings of HCV chronically infected children

BACKGROUND

Cell-mediated immune (CMI) responses to hepatitis C virus (HCV) antigens in adults without seroconversion or viremia are biomarkers for prior transient infection. We investigated HCV-specific CMI responses in seronegative children living with HCV-infected siblings.

METHODS

Children 3-18 years of age living with HCV-infected siblings were screened for HCV antibodies and HCV RNA. Peripheral blood mononuclear cells (PBMCs) were evaluated for HCV-specific CMI responses by interferon γ (IFN-γ) enzyme-linked immunospot assay using 3 recombinant HCV protein antigens. Flow cytometry phenotypically characterized IFN-γ-secreting cells.

RESULTS

Forty-five seronegative children and 5 seropositive viremic siblings had functionally viable PBMCs. Among the 45 seronegative siblings, 15 (33.3%) had positive HCV-specific IFN-γ responses, and subsequent RNA testing revealed that 3 were viremic. Compared with the 5 seropositive viremic children, the median number of HCV-specific spot-forming units was significantly higher in the 12 seronegative aviremic children (P = .002) and in the 3 seronegative viremic children (P = .025). Flow cytometric analysis revealed that IFN-γ was synthesized mainly by CD4(+) T cells.

CONCLUSION

Strong HCV-specific CD4(+) T cell responses were detectable in higher frequency among seronegative, aviremic children compared with persistently infected siblings. Further studies are needed to determine whether these immune responses are protective against HCV infection.

Human immunodeficiency virus (HIV)-1 infects human hepatic stellate cells and promotes collagen I and monocyte chemoattractant protein-1 expression: implications for the pathogenesis of HIV/hepatitis C virus-induced liver fibrosis

Patients coinfected with human immunodeficiency virus (HIV) and hepatitis C virus (HCV) develop more rapid fibrosis than those infected with HCV only. In HIV/HCV-coinfected patients, fibrosis progression correlates with HIV RNA levels, suggesting a direct role of HIV in liver fibrogenesis. Chemokine (C-C motif) receptor 5 (CCR5) and cysteine-X-cysteine receptor 4 (CXCR4), the two major coreceptors required for HIV entry into cells, are expressed on activated hepatic stellate cells (HSCs), the principle fibrogenic cell type in the liver. We therefore examined whether HIV can infect HSCs, explored the potential mechanisms of viral entry, and assessed the impact of infection as reflected by the ability of HSCs to transfer virus to T lymphocytes and elicit a proinflammatory and profibrogenic response. We report that the laboratory-adapted viruses HIV-IIIB (CXCR4-tropic or X4) and HIV-BaL (CCR5-tropic or R5) and primary HIV isolates can infect both a human stellate cell line, LX-2, and primary human HSCs. HIV entry and gene expression in HSCs was confirmed using HIV-green fluorescent protein (GFP) expression viral constructs in the presence or absence of the reverse-transcriptase inhibitor azidothymidine. CD4 expression on a subset of primary HSCs was demonstrated using fluorescence-activated cell sorting and immunofluorescence staining. Blocking experiments in the presence of anti-CD4, anti-CXCR4, and anti-CCR5 revealed that HIV entry into HSCs is predominantly CD4/chemokine coreceptor-independent. HIV infection promoted HSC collagen I expression and secretion of the proinflammatory cytokine monocyte chemoattractant protein-1. Furthermore, infected LX-2 cells were capable of transferring GFP-expressing virus to T lymphocytes in a coculture system.

CONCLUSION

Taken together, our results suggest a potential role of HIV in liver fibrosis/inflammation mediated through effects on HSCs. The role of early highly active antiretroviral therapy initiation in patients with HIV/HCV coinfection warrants further investigation.

Impact of hepatitis C viral replication on CD4+ T-lymphocyte progression in HIV-HCV coinfection before and after antiretroviral therapy

OBJECTIVE

HIV is known to have a negative impact on the progression of hepatitis C virus (HCV) infection, whereas the reverse remains unclear. We examined the impact of spontaneous clearance of HCV on CD4(+) T-lymphocyte count progression before and after initiation of antiretroviral therapy (ART) in HIV-HCV coinfected adults.

METHODS

Data were analysed from participants in a Canadian, multisite prospective cohort of HIV-infected adults with serologic evidence of HCV infection. The rate of CD4(+) T-lymphocyte change was determined using multivariate mixed linear regression comparing chronically HCV RNA+ with spontaneous clearers (persistently HCV RNA- without HCV therapy).

RESULTS

Baseline characteristics of the 271 participants analysed did not differ between individuals whose HCV RNA cleared (n = 35) and those whose HCV RNA persisted (n = 236) except with respect to markers of liver disease. HCV RNA+ individuals had on average seven-times slower recovery of CD4(+) T-cells on chronic ART compared with HCV RNA-: (adjusted change in absolute CD4 cell T-lymphocyte count per year: 4 (95% confidence interval, -0.6 to 8) cells/microl vs. 26 (95% confidence interval, 12 to 41) cells/microl; P < 0.001. Analyses restricted to individuals initiating ART showed similar results. There was also a trend to greater CD4 decline prior to ART initiation among those HCV RNA+, although this did not reach statistical significance.

CONCLUSION

We found that CD4 cell progression is negatively affected by the presence of ongoing HCV replication in coinfected individuals initiating ART which persisted throughout stable ART suggesting active HCV infection affects immune restoration even after years of ART exposure.

Pathogenesis of HIV-HCV Coinfection

Hepatitis C virus (HCV) and HIV-1 are often harbored in the same host, establishing chronic infections typically characterized by persistent viremia. HIV-1 has deleterious effects on the course of HCV infection by increasing the rate of HCV viral persistence, quantitative HCV RNA levels, and ultimately the liver fibrosis progression rate. Conversely, HCV may blunt the effectiveness of immune reconstitution following antiretroviral therapy in HIV-infected individuals. Better understanding of the pathogenic mechanisms underlying these clinical observations may facilitate novel and effective therapeutic interventions that tackle the clinical conundrums raised by HIV/HCV coinfection.

Coinfection with HIV-1 and HCV--a one-two punch

Hepatitis C virus (HCV) infection is a major cause of chronic liver disease, cirrhosis, and death; it is estimated that 180 million persons are infected with HCV worldwide. The consequences of HCV are worse in those who are coinfected with human immunodeficiency virus 1 (HIV-1), which is unfortunately a common scenario because of shared risk factors of the viruses. More studies into effects of HCV/HIV-1 coinfection are needed, but efforts have been hampered by limitations in our understanding of the combined pathogenesis of the 2 viruses. Gaining insight into the mechanisms that underlie the immunopathogenesis of these persistent viral infections could lead to new therapeutic strategies for patients with HCV/HIV-1 coinfection.

Inhibition of intrahepatic gamma interferon production by hepatitis C virus nonstructural protein 5A in transgenic mice

Hepatitis C virus (HCV) utilizes strategies to suppress or evade the host immune response for establishment of persistent infection. We have shown previously that HCV nonstructural protein 5A (NS5A) impairs tumor necrosis factor alpha (TNF-alpha)-mediated apoptosis. In this study, we have examined the immunomodulatory role of HCV NS5A protein in transgenic mouse (NS5A-Tg) liver when mice were challenged with an unrelated hepatotropic adenovirus as a nonspecific stimulus. Hepatotropic adenovirus was introduced intravenously into NS5A-Tg mice and control mice, and virus clearance from liver was compared over a time course of 3 weeks. The differential mRNA expression levels of 84 cytokine-related genes, signal pathway molecules, transcription factors, and cell surface molecules were determined using real-time reverse transcription-PCR array. NS5A-Tg mice failed to clear adenovirus from liver up to 3 weeks postinfection while control mice cleared virus within 1 to 2 weeks. Subsequent study revealed that gamma interferon (IFN-gamma) expression is inhibited at both the mRNA and protein levels in NS5A-Tg mice, and an inverse expression of transcription factors Gata-3 and Tbx21 is observed. However, TNF-alpha mRNA and protein expression were elevated in both NS5A-Tg and control mice. Together, our results suggested that HCV NS5A acts as an immunomodulator by inhibiting IFN-gamma production and may play an important role toward establishment of chronic HCV infection.

Impaired quality of the hepatitis B virus (HBV)-specific T-cell response in human immunodeficiency virus type 1-HBV coinfection

Hepatitis B virus (HBV)-specific T cells play a key role both in the control of HBV replication and in the pathogenesis of liver disease. Human immunodeficiency virus type 1 (HIV-1) coinfection and the presence or absence of HBV e (precore) antigen (HBeAg) significantly alter the natural history of chronic HBV infection. We examined the HBV-specific T-cell responses in treatment-naïve HBeAg-positive and HBeAg-negative HIV-1-HBV-coinfected (n = 24) and HBV-monoinfected (n = 39) Asian patients. Peripheral blood was stimulated with an overlapping peptide library for the whole HBV genome, and tumor necrosis factor alpha and gamma interferon cytokine expression in CD8+ T cells was measured by intracellular cytokine staining and flow cytometry. There was no difference in the overall magnitude of the HBV-specific T-cell responses, but the quality of the response was significantly impaired in HIV-1-HBV-coinfected patients compared with monoinfected patients. In coinfected patients, HBV-specific T cells rarely produced more than one cytokine and responded to fewer HBV proteins than in monoinfected patients. Overall, the frequency and quality of the HBV-specific T-cell responses increased with a higher CD4+ T-cell count (P = 0.018 and 0.032, respectively). There was no relationship between circulating HBV-specific T cells and liver damage as measured by activity and fibrosis scores, and the HBV-specific T-cell responses were not significantly different in patients with either HBeAg-positive or HBeAg-negative disease. The quality of the HBV-specific T-cell response is impaired in the setting of HIV-1-HBV coinfection and is related to the CD4+ T-cell count.

Differences in Virological Response to Pegylated Interferon and Ribavirin between Hepatitis C Virus (Hcv)-Monoinfected and HCV–Hiv-Coinfected Patients

Background

Suboptimal doses of ribavirin have been suggested to explain the diminished efficacy of pegylated interferon (PEG-IFN) plus ribavirin in hepatitis C virus (HCV)–HIV-coinfected patients.

Methods

A cohort of 104 coinfected patients and an age-, sex- and genotype-matched cohort of HCV-monoinfected patients ( n=104) were compared. All patients received PEG-IFN-α2a 180 μg/week plus ribavirin 800–1,200 mg daily (HCV genotype 2/3 patients received 800 mg daily and those with genotype 1/4 received 1,000–1,200 mg daily) for 48 weeks (24 weeks for monoinfected patients with genotypes 2/3). HCV RNA levels were determined qualitatively at weeks 4, 12, 24, 48 and 72 and quantified monthly until week 12.

Results

The coinfected cohort had more advanced liver disease and lower body weight. HCV genotype 1 patients coinfected with HIV showed higher levels of HCV RNA than monoinfected patients. A significantly higher proportion of coinfected patients interrupted the prescribed treatment period prematurely (84% versus 98%). During the first 12 weeks, smaller decreases in HCV RNA levels were observed in coinfected patients. Among patients with HCV genotype 1, coinfected patients achieved lower rates of early virological response (64% versus 87%), end-of-treatment response (47.3% versus 80%) and sustained virological response (SVR; 27.3% versus 56.4%), but not rapid virological response (RVR). HCV–HIV-coinfected patients with HCV genotype 2/3 achieved significantly lower rates of RVR (52% versus 88%). Multivariate analysis identified RVR, gender and liver fibrosis as independent predictors of SVR.

Conclusions

Differences in efficacy of PEG-IFN-α2a plus ribavirin treatment between HCV–HIV-coinfected and HCV-monoinfected patients were maintained despite optimized ribavirin dose.

Cellular and molecular interactions in coinfection with hepatitis C virus and human immunodeficiency virus

Coinfection with hepatitis C virus (HCV) and human immunodeficiency virus (HIV) is associated with increased HCV replication and a more rapid progression to severe liver disease, including the development of cirrhosis and hepatocellular carcinoma. In this review, we discuss the current understanding of the pathogenesis of HCV/HIV coinfection and the cellular and molecular mechanisms associated with the accelerated course of liver disease. The strength and breadth of HCV-specific T-cell responses are reduced in HCV/HIV-coinfected patients compared with those infected with HCV alone, suggesting that the immunosuppression induced by HIV compromises immune responses to HCV. HCV is not directly cytopathic, but many of the pathological changes observed in the liver of infected patients are a direct result of the intrahepatic antiviral immune responses. Apoptosis also has a role in HCV-mediated liver damage through the induction of apoptotic pathways involving the host immune response and HCV viral proteins. This review summarises the evidence correlating the role of cell-mediated immune responses and apoptosis with liver disease progression in HCV/HIV-coinfected patients.

HIV-specific T-cells accumulate in the liver in HCV/HIV co-infection

Background and Aims

Hepatitis C Virus (HCV)-related liver disease progresses more rapidly in individuals co-infected with Human Immunodeficiency Virus-1 (HIV), although the underlying immunologic mechanisms are unknown. We examined whether HIV-specific T-cells are identified in the liver of HCV/HIV co-infected individuals and promote liver inflammation through bystander immune responses.

Methods

Ex-vivo intra-hepatic lymphocytes from HCV mono-infected and HCV/HIV co-infected individuals were assessed for immune responses to HIV and HCV antigens by polychromatic flow cytometry.

Results

HCV/HIV liver biopsies had similar frequencies of lymphocytes but lower percentages of CD4⁺ T-cells compared to HCV biopsies. In co-infection, intra-hepatic HIV-specific CD8⁺ and CD4⁺ T-cells producing IFN-γ and TNF-α were detected and were comparable in frequency to those that were HCV-specific. In co-infected individuals, viral-specific CD8⁺ T-cells produced more of the fibrogenic cytokine, TNF-α. In both mono- and co-infected individuals, intra-hepatic HCV-specific T-cells were poorly functional compared to HIV-specific T-cells. In co-infection, HAART was not associated with a reconstitution of intra-hepatic CD4⁺ T-cells and was associated with reduction in both HIV and HCV-specific intra-hepatic cytokine responses.

Conclusion

The accumulation of functional HIV-specific T-cells in the liver during HCV/HIV co-infection may represent a bystander role for HIV in inducing faster progression of liver disease.

Hepatitis C virus-specific T-cell gamma interferon and proliferative responses are more common in perihepatic lymph nodes than in peripheral blood or liver

The activation state, differentiation state, and functions of liver lymphocytes and perihepatic lymph nodes during chronic hepatitis C virus (HCV) infection are not well understood. Here, we performed phenotypic and functional analyses of freshly prepared lymphocytes isolated from the livers, perihepatic lymph nodes, and peripheral blood compartments of chronic HCV-infected and disease control subjects with end-stage liver disease undergoing liver transplantation. We measured lymphocyte subset frequency and memory T-cell gamma interferon (IFN-gamma) and proliferative responses to HCV peptide and control viral antigens in direct ex vivo assays. We found higher frequencies of CD4 cells in the lymph node compartment than in the other compartments for both HCV-infected and disease control subjects. Lymph node CD4 and CD8 cells less commonly expressed the terminal differentiation marker CD57, a finding consistent with an earlier differentiation state. In HCV-infected subjects, HCV-specific IFN-gamma-producing and proliferative responses were commonly observed in the lymph node fraction, while they were uncommonly observed in the peripheral blood or liver fractions. In contrast, control viral CD4 protein antigen and CD8 peptide antigen-specific IFN-gamma responses were commonly observed in the periphery and uncommonly observed in the lymph nodes of these same subjects. These findings are consistent with a selective defect in HCV-specific T-cell effector function or distribution in patients with advanced chronic HCV infection. The high frequency of HCV-reactive T cells in perihepatic lymph nodes indicates that a failure to generate or sustain T-lymphocyte HCV reactivity is not responsible for the paucity of functional cells even in end-stage liver disease.

Hepatic steatosis in patients with HIV-Hepatitis C Virus coinfection: is it associated with antiretroviral therapy and more advanced hepatic fibrosis?

BACKGROUND AND AIMS

Patients with HIV and hepatitis C virus (HCV) coinfection are at increased risk of developing hepatic steatosis. The aims of this study were to assess the prevalence of steatosis in a cohort with HIV-HCV coinfection, and to determine an association, if any, between steatosis, antiretroviral therapy (ART), and advanced hepatic fibrosis.

PATIENTS AND METHODS

HIV-HCV coinfected patients were retrospectively identified from the HIV clinic. ART was classified as none, nucleoside reverse transcriptase inhibitors (NRTIs) only, highly active antiretroviral therapy (HAART) only, and sequential therapy (initial NRTIs followed by HAART). Fibrosis stage and necroinflammation grade were assessed by the modified HAI (Ishak) scoring method. Steatosis was graded as 0-3.

RESULTS

Sixty patients were identified. The overall prevalence of hepatic steatosis was 58%. Those that received HAART only had a lower prevalence of steatosis (41%) compared to those on NRTIs only (70%) or sequential therapy (82%). Independent predictors of hepatic steatosis were absence of HAART only therapy, OR 2.9, p = 0.09, and presence of cirrhosis, OR 4.6, p = 0.044. Forty five percent of the patients had advanced fibrosis (fibrosis stage >/= 3). NI grade (OR 1.9, p = 0.030), and steatosis grade (OR 3.6, p = 0.045), were independent predictors of advanced fibrosis.

CONCLUSION

Hepatic steatosis is associated with more advanced hepatic fibrosis in the HIV-HCV coinfected population. HAART only therapy (rather than NRTIs only or sequential therapy) appears to be associated with a lower prevalence of hepatic steatosis. This may be one of the mechanisms by which HAART could attenuate hepatic fibrosis in such a cohort.

Hepatic inflammatory cytokine mRNA expression in hepatitis C virus-human immunodeficiency virus co-infection

Although epidemiologic studies have documented that hepatitis C virus (HCV)/human immunodeficiency virus (HIV) co-infected patients have accelerated fibrogenesis, especially those with CD4+ cell counts <200 cells/mm(3), the pathogenic mechanisms are poorly understood. We investigated whether severe immunodeficiency in co-infection is associated with changes in intrahepatic inflammatory cytokine mRNA levels. We measured interferon (IFN)-gamma, tumour necrosis factor-alpha, transforming growth factor (TGF)-beta(1), interleukin (IL)-4, IL-10, IL-12p35 and IL-12p40 mRNA levels by real-time PCR performed on liver samples from HCV mono-infected (n = 19) and HCV/HIV co-infected (n = 24) patients. Co-infected patients had decreased intrahepatic mRNA levels of IFN-gamma (P = 0.09), IL-4 (P = 0.05) and IL-12p35 (P = 0.04) compared with mono-infected patients, while IL-10 was increased (P = 0.07). In co-infected patients, IFN-gamma mRNA levels increased linearly with increasing peripheral CD4+ cell counts by 1.23 times relative to the calibrator for every 100 CD4+ cells/mm(3) increase (P = 0.02). No other cytokines were significantly associated with CD4+ cell counts. In conclusion, HIV-induced lymphopenia may result in hepatic inflammatory cytokine suppression in HCV/HIV co-infection. Intrahepatic IFN-gamma levels are significantly reduced in patients with advanced immunodeficiency. Further studies are needed to assess whether decreased IFN-gamma secretion by HCV-specific CD4+ cells may account for accelerated fibrogenesis in these patients.

HCV/ HIV co-infection: time to re-evaluate the role of HIV in the liver?

Because of major advances in the treatment of HIV/AIDS, HIV-positive persons now live longer, healthier lives; however, hepatitis C virus (HCV) is increasingly recognized as a major cause of morbidity and mortality in this population. Among HCV-infected persons, HIV co-infection is associated with increased HCV RNA levels, increased hepatic inflammation and fibrosis, and more rapid progression to cirrhosis and end-stage liver disease. Compounding this problem are reduced HCV treatment response rates among HCV/HIV co-infected persons. Moreover, antiretroviral therapy used to suppress HIV replication is often associated with a paradoxical increase in HCV RNA levels, as well as hepatotoxicity. Despite the adverse clinical consequences of HCV/HIV co-infection, the mechanisms by which these two viruses interact at the cellular level remain largely unexplored. This review focuses on the evidence demonstrating direct infection of hepatocytes by HIV, as well as the indirect mechanisms by which HIV may regulate HCV replication at the cellular level. A comprehensive understanding of virus-virus and virus-cell interactions is critical to the development of novel treatment strategies to combat HCV/HIV co-infection.

Intrahepatic mRNA expression in hepatitis C virus and HIV/hepatitis C virus co-infection: infiltrating cells, cytokines, and influence of HAART

OBJECTIVE

Liver disease is more progressive in HIV/hepatitis C virus (HCV) co-infection than in HCV infection alone. This accelerated pathogenesis is probably influenced by differences in the composition of infiltrating inflammatory cells and the local release of inflammatory and profibrogenic cytokines.

METHODS

Using quantitative real-time reverse transcriptase-polymerase chain reaction (qRT-PCR) we studied intrahepatic messenger RNA levels of cytokines and cellular markers defining distinct subsets of inflammatory cells in liver biopsies from 33 HCV-mono-infected and 40 HIV/HCV-co-infected patients.

RESULTS

Despite their well preserved peripheral blood CD4 cell counts (median 598 cells/microl), HIV/HCV-co-infected patients displayed significantly lower CD4 mRNA levels than HCV-mono-infected patients, whereas increased mRNA levels of CD3epsilon, TCRalpha, CD8alpha and CD8beta suggested intrahepatic enrichment of CD8 T cells in HIV co-infection. Intrahepatic mRNA levels of the inflammatory cytokines interferon gamma (IFN-gamma), regulated upon activation, normal T-cell expressed and secreted (RANTES, CCL5), macrophage inflammatory protein 1 alpha (CCL3) and interferon-inducible protein 10 (CXCL10) were significantly higher in HIV-positive than in HIV-negative patients, whereas mRNA levels of the profibrogenic cytokines macrophage chemoattractant protein 1 (CCL2), secondary lymphochemokine (CCL21) and stroma-derived factor 1 (CXCL12) did not differ between the two groups. All changes were less pronounced in the subgroup of HIV-positive patients receiving antiretroviral treatment (HAART) than in untreated HIV-positive patients.

CONCLUSION

The accelerated liver disease observed in HIV/HCV-co-infected patients might reflect enhanced intrahepatic inflammatory responses rather than increased local transcription of directly profibrogenic cytokines.

HCV-HIV coinfection: simple messages from a complex disease

The authors discuss our current understanding of the immunopathogenesis of HCV-HIV coinfection.

Clinicoimmunological progression and response to treatment of long-term nonprogressor HIV-hepatitis C virus-coinfected patients

We assess the severity and response to treatment of hepatitis C virus (HCV) infection in a cohort of long-term nonprogressors (LTNP) and analyze whether HCV infection affects the progression of HIV-1 infection. A case-control study comparing coinfected LTNP (n = 28) with coinfected normal progressors (NP) (n = 56) was performed. Signs of hepatopathy, response to HCV treatment, HIV viral load (VL), and lymphocyte T subsets were analyzed. A cohort of LTNP with (n = 28) and without HCV infection (n = 7) was compared to assess the influence of HCV on HIV-1 infection. Liver enzymes were lower in LTNP than in NP. There were no significant differences between LTNP and NP in clinical signs of chronic liver disease at physical examination, echostructure, degree of inflammation, or fibrosis score in liver biopsy. There were no differences in the response to HCV treatment between groups (57% vs. 45%, p = 0.69). LTNP presented a proportionally higher drop of CD4 during HCV treatment, which persisted 2 years after discontinuing treatment [-195, -10, and 30 cells/mm3 HCV-treated LTNP (n = 7), NP (n = 56), and non-HCV-treated LTNP (n = 21), respectively, p < 0.05]. There were no differences in any variables analyzed when coinfected and monoinfected LTNP were compared. LTNP do not seem to have a better outcome or response to HCV treatment than NP. HCV-treated LTNP could have a worse HIV progression than HIV-HCV-treated NP or untreated coinfected LTNP. HCV infection does not have a deleterious effect on the progression of LTNP.

[Evaluation of the cellular immunity in patients coinfected by the hepatitis C virus and the human immunodeficiency virus]

BACKGROUND

The immune activation provoked by the hepatitis C virus can be deleterious in patients with human immunodeficiency virus, favouring the destruction of CD4 cells. By the other side, the immune restoration observed after the onset of antiretroviral therapy can be partially obscured in patients with the hepatitis C virus.

AIM

The objective of the present study was to evaluate the impact of coinfection by hepatitis C virus and the human immunodeficiency virus in the cellular immunity.

METHODS

Two groups of patients were considered: coinfected patients were prospectively evaluated in the gastroenterology clinic at "Hospital Nossa Senhora da Conceição", Porto Alegre, RS, Brazil (group 1 - 385 patients), and monoinfected patients by human immunodeficiency virus based on the review of the charts from the infectious diseases clinic (group 2 - 198 patients). Demographic (gender, race, age) CD4 and CD8 cell count, CD4/CD8 index and human immunodeficiency virus viral load were evaluated. A 5% significance level was adopted.

RESULTS

There were no difference between the parameters evaluated: mean CD4 count (374,7 +/- 215,7 x 357,5 +/- 266,0), CD8 (1.512,4 +/- 7.274,6 x 986,7 +/- 436,4) and HIV viral load (83.744,2 +/- 190.292,0 x 104.464,0 +/- 486.880,5) respectively in both groups evaluated, as well as the proportion of patients with CD4/CD8 rate below 1.

CONCLUSION

Coinfection by both viruses did not have a negative impact in relation to monoinfection by human immunodeficiency virus, and the immune profile was similar in all groups.

Hepatitis C virus (HCV)-specific CD8+ cells produce transforming growth factor beta that can suppress HCV-specific T-cell responses

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-gamma) enzyme-linked immuno-spot 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 beta1 (TGF-beta1), -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-gamma effect was observed for both CD4 and CD8 T cells and was mediated primarily by TGF-beta1, -2, and -3 neutralization. In conclusion, blockade of TGF-beta secretion could enhance peripheral HCV-specific T-cell responses even in the presence of HIV coinfection.

Cellular immune responses against hepatitis C virus

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.

Intrahepatic virus-specific IL-10-producing CD8 T cells prevent liver damage during chronic hepatitis C virus infection

CD8 T cell killing of hepatitis C virus (HCV)-infected hepatocytes is thought to contribute to liver damage during chronic HCV infection, whereas the participation of HCV-nonspecific immune cells is unclear. To visualize the spatial relationship of HCV-specific CD8 T cells with parenchymal target cells, and to examine their local functional activity in relation to hepatocellular necrosis and fibrosis, we used HLA tetramers and confocal microscopy in biopsies from 23 HLA-A2 or HLA-B7 patients with chronic HCV infection. Intrahepatic tetramer+ (HCV-specific) CD8 T cells protected from hepatic necroinflammatory disease activity, independently of age, gender, viral load, and viral genotype. Indeed, tetramer+ cells were scattered in the liver within regions of weak fibrosis (low laminin expression) and low hepatocellular apoptosis (TUNEL method), and expressed IL-10 but not IFNgamma. By contrast, tetramer-negative CD8 T cells were associated with active necroinflammatory liver disease, colocalized with strong laminin expression and hepatocellular apoptosis, and expressed more frequently IFNgamma than IL-10. Overall, liver regions harboring HCV-specific CD8 T cells tended to be healthier than areas containing only inflammatory cells of undefined specificity. In conclusion, HCV-specific IL-10-producing CD8 T cells, although not cytotoxic and unable to control viral replication, can attenuate hepatocellular necrosis, liver fibrosis, and inflammation mediated by bystander T cells, and may thus represent antigen-induced regulatory CD8 T cells. Therapeutic modulation of the intrahepatic balance between specific and bystander CD8 T cells might be beneficial in patients with chronic hepatitis C.

Impaired hepatitis C virus-specific T cell responses and recurrent hepatitis C virus in HIV coinfection

BACKGROUND

Hepatitis C virus (HCV)-specific T cell responses are critical for spontaneous resolution of HCV viremia. Here we examined the effect of a lymphotropic virus, HIV-1, on the ability of coinfected patients to maintain spontaneous control of HCV infection.

METHODS AND FINDINGS

We measured T cell responsiveness by lymphoproliferation and interferon-gamma ELISPOT in a large cohort of HCV-infected individuals with and without HIV infection. Among 47 HCV/HIV-1-coinfected individuals, spontaneous control of HCV was associated with more frequent HCV-specific lymphoproliferative (LP) responses (35%) compared to coinfected persons who exhibited chronic HCV viremia (7%, p = 0.016), but less frequent compared to HCV controllers who were not HIV infected (86%, p = 0.003). Preservation of HCV-specific LP responses in coinfected individuals was associated with a higher nadir CD4 count (r(2) = 0.45, p < 0.001) and the presence and magnitude of the HCV-specific CD8(+) T cell interferon-gamma response (p = 0.0014). During long-term follow-up, recurrence of HCV viremia occurred in six of 25 coinfected individuals with prior control of HCV, but in 0 of 16 HIV-1-negative HCV controllers (p = 0.03, log rank test). In these six individuals with recurrent HCV viremia, the magnitude of HCV viremia following recurrence inversely correlated with the CD4 count at time of breakthrough (r = -0.94, p = 0.017).

CONCLUSIONS

These results indicate that HIV infection impairs the immune response to HCV-including in persons who have cleared HCV infection-and that HIV-1-infected individuals with spontaneous control of HCV remain at significant risk for a second episode of HCV viremia. These findings highlight the need for repeat viral RNA testing of apparent controllers of HCV infection in the setting of HIV-1 coinfection and provide a possible explanation for the higher rate of HCV persistence observed in this population.

Relationships between cellular immune responses and treatment outcomes with interferon and ribavirin in HIV/hepatitis C virus co-infection

OBJECTIVE

To test the hypothesis that hepatitis C virus (HCV)-specific interferon (IFN)gamma immune responses are correlated with HCV virological response following treatment in subjects with HIV-1 and HCV co-infection.

DESIGN

Immune responses were studied in a treatment trial comparing standard interferon alfa (IFN) to pegylated interferon alfa (PEG-IFN), each with ribavirin (R).

METHODS

Using HCV antigens core, NS3 and NS5, and Candida, enzyme-linked immunosorbent spots on peripheral blood mononuclear cells measured IFNgamma and interleukin (IL)-10 production. Immunologic, virologic and clinical variables were modeled using recursive partitioning (CART) to identify factors associated with HCV virological response at week 24 (VR) and week 72 (SVR) in 108 patients.

RESULTS

There were no significant differences in baseline IFNgamma immune responses and higher IL-10 to NS3 in subjects with VR versus non-responders. Subjects who had significant decreases in IL-10 responses at week 24 compared to baseline for NS3, NS5, or summed HCV responses were more likely to be VR. Using baseline immunological responses and clinical data in CART models, patients who were randomized to PEG-IFN/R and had high IL-10 responses to summed HCV proteins were more likely to be VR (73%), whereas those on IFN/R who had low IFNgamma responses to Candida were less likely to be VR (5%). The main correlate of SVR for genotype-1 subjects was maintenance of HCV-specific IFNgamma responses from baseline to week 72.

CONCLUSIONS

In this cohort of subjects with HIV and HCV, a decrease in HCV-specific IL-10 responses and maintenance of IFNgamma responses during treatment with IFN were associated with week 24 or 72 virological response.

Shared alterations in NK cell frequency, phenotype, and function in chronic human immunodeficiency virus and hepatitis C virus infections

Human immunodeficiency virus (HIV) and hepatitis C virus (HCV) cause clinically important persistent infections. The effects of virus persistence on innate immunity, including NK cell responses, and the underlying mechanisms are not fully understood. We examined the frequency, phenotype, and function of peripheral blood CD3- CD56+ NK subsets in HIV+ and HCV+ patients and identified significantly reduced numbers of total NK cells and a striking shift in NK subsets, with a marked decrease in the CD56(dim) cell fraction compared to CD56(bright) cells, in both infections. This shift influenced the phenotype and functional capacity (gamma interferon production, killing) of the total NK pool. In addition, abnormalities in the functional capacity of the CD56(dim) NK subset were observed in HIV+ patients. The shared NK alterations were found to be associated with a significant reduction in serum levels of the innate cytokine interleukin 15 (IL-15). In vitro stimulation with IL-15 rescued NK cells of HIV+ and HCV+ patients from apoptosis and enhanced proliferation and functional activity. We hypothesize that the reduced levels of IL-15 present in the serum during HIV and HCV infections might impact NK cell homeostasis, contributing to the common alterations of the NK pool observed in these unrelated infections.

Update on Hepatitis B and C Coinfection in HIV

Coinfection with hepatitis B virus (HBV) or hepatitis C virus (HCV) is common in patients with HIV infection. HIV infection and immunosuppression alter the natural history of chronic viral hepatitis, and some patients experience accelerated progression to clinically significant liver disease. Therapies used in the treatment of HBV or HCV monoinfection have been applied to the treatment of HIV-coinfected patients. However, development of viral resistance and lack of virologic response remain significant areas of concern. Timely diagnosis and clinical staging of chronic hepatitis infection are critical in the management of HIV-coinfected patients.

T-cell response relative to genotype and ethnicity during antiviral therapy for chronic hepatitis C

Viral genotype and host ethnicity are important predictors of viral clearance during antiviral therapy for chronic hepatitis C virus (HCV) infection. Based on the role of T cells in natural HCV clearance, we hypothesized that T cells may contribute to the genotypic and ethnic difference in treatment outcome. To test this hypothesis, T-cell response to HCV antigens (core, nonstructural NS3/4 and NS5) and control phytohemagglutinin (PHA) was monitored prospectively and was correlated with virological outcome in 41 patients chronically infected with HCV (27 genotype 1, 14 genotype 2 or 3; 19 black persons, 22 white persons) undergoing combined interferon alfa and ribavirin therapy. Interestingly, in patients with genotype 2 or 3 infection, enhanced virological response coincided with a greater T-cell response to HCV NS3/4 antigen at baseline (50% vs. 15%; P = .026) that augmented further during therapy (29% vs. 4%; P = .035) compared with genotype 1-infected patients. However, HCV-specific T-cell response remained weak in genotype 1-infected patients regardless of virological outcome or ethnicity. Furthermore, virological outcome was associated with a suppressed baseline proliferative response to phytohemagglutinin (P < .03) that increased during therapy (P < .003) independent of ethnicity or genotype. In conclusion, HCV-specific T-cell response was associated with HCV genotype but not with therapeutic clearance of HCV infection. The association between treatment outcome and phytohemagglutinin response suggests more global and antigen-nonspecific mechanisms for therapeutic HCV clearance.

Antigen-specific immune responses and liver histology in HIV and hepatitis C coinfection

OBJECTIVE

To test the hypothesis that antigen-specific interferon (IFN)gamma responses are correlated with milder liver disease in subjects coinfected with HIV-1 and hepatitis C virus (HCV).

DESIGN

Cellular immune responses were studied in a cohort with HIV/HCV coinfection (n = 107) who underwent liver biopsy.

METHODS

We measured HCV-specific and recall responses in peripheral blood mononuclear cells using IFNgamma and interleukin (IL)-10 ELISpots, and correlated these immune responses with liver histology. The relationship of immunologic, virologic and clinical variables to inflammation and fibrosis was modeled using recursive partitioning.

RESULTS

There were significant negative correlations between inflammatory scores and IFNgamma production in response to the HCV proteins core, NS5 and summed HCV responses. Lower fibrosis scores were also correlated with higher IFNgamma production in response to NS5 and summed HCV proteins. Higher IFNgamma production in response to Candida was significantly associated with lower inflammatory and fibrosis scores. In multivariable models, factors associated with severe fibrosis were lower IFNgamma responses to Candida and summed HCV proteins. Factors associated with severe inflammation were detectable HIV viral load and lower HCV viral load, while predictors of mild inflammation included undetectable HIV viral load and higher IFNgamma response to Candida.

CONCLUSIONS

In this cohort of subjects coinfected with HIV and HCV, antigen-specific IFNgamma responses are correlated with milder inflammation and fibrosis. Immunological responses best predicted severity of fibrosis, while clinical variables and recall antigen responses best predicted severity of inflammation.