Lack of TGF-β production by hepatitis C virus-specific T cells during HCV acute phase is associated with HCV clearance in HIV coinfection

Estimating the Time to Diagnosis and the Chance of Spontaneous Clearance During Acute Hepatitis C in Human Immunodeficiency Virus-Infected Individuals

BACKGROUND

Hepatitis C virus (HCV) infection is often asymptomatic, and the date of infection is almost impossible to determine. Furthermore, spontaneous clearance (SC) may occur, but little is known about its time of occurrence.

METHODS

Data on human immunodeficiency virus (HIV)-HCV coinfected individuals were used to inform a stochastic simulation model of HCV viral load kinetics, alanine aminotransferase (ALT), and HCV antibodies during acute hepatitis C. The dates of diagnosis and potential SC were estimated through a Bayesian approach. Hepatitis C virus diagnosis was assumed to be based on an elevated ALT level detected during a control visit for HIV-infected individuals, which occurred every 3 months (scenario A) or every 6 months (scenario B).

RESULTS

We found that HCV diagnosis occurred after a median of 115 days and 170 days of infection in scenarios A and B, respectively. Among spontaneous clearers, SC occurred after a median time of 184 days after infection. Seven percent (scenario B) to 10% (scenario A) of SCs appeared more than 6 months after diagnosis, and 3% (both scenarios) of SCs appeared more than 1 year after diagnosis.

CONCLUSIONS

Acute hepatitis C diagnosis occurs late in HIV-HCV coinfected individuals. Screening for HCV in HIV-infected individuals should be performed frequently to reduce delays. Our findings about late occurrence of SC support "wait and see" strategies for treatment initiation from an individual basis. However, early treatment initiation may reduce HCV transmission.

Immune regulation in chronic hepatitis C virus infection

The immunological result of infection with Hepatitis C virus (HCV) depends on the delicate balance between a vigorous immune response that may clear the infection, but with a risk of unspecific inflammation and, or a less inflammatory response that leads to chronic infection. In general, exhaustion and impairment of cytotoxic function of HCV-specific T cells and NK cells are found in patients with chronic HCV infection. In contrast, an increase in immune regulatory functions is found primarily in form of increased IL-10 production possibly due to increased level and function of anti-inflammatory Tregs. Thus, the major immune players during chronic HCV infection are characterized by a decrease of cytotoxic function and increase of inhibitory functions. This may be an approach to diminish intrahepatic and systemic inflammation. Finally, there has been increasing awareness of regulatory functions of epigenetic changes in chronic HCV infection. A vast amount of studies have revealed the complexity of immune regulation in chronic HCV infection, but the interplay between immune regulation in virus and host remains incompletely understood. This review provides an overview of regulatory functions of HCV-specific T cells, NK cells, Tregs, IL-10, and TGF-β, as well as epigenetic changes in the setting of chronic HCV infection.

A unique CD8(+) T lymphocyte signature in pediatric type 1 diabetes

Human type 1 diabetes results from a destructive auto-reactive immune response in which CD8(+) T lymphocytes play a critical role. Given the intense ongoing efforts to develop immune intervention to prevent and/or cure the disease, biomarkers suitable for prediction of disease risk and progress, as well as for monitoring of immunotherapy are required. We undertook separate multi-parameter analyses of single naïve and activated/memory CD8(+) T lymphocytes from pediatric and adult patients, with the objective of identifying cellular profiles associated with onset of type 1 diabetes. We observe global perturbations in gene and protein expression and in the abundance of T cell populations characterizing pediatric but not adult patients, relative to age-matched healthy individuals. Pediatric diabetes is associated with a unique population of CD8(+) T lymphocytes co-expressing effector (perforin, granzyme B) and regulatory (transforming growth factor β, interleukin-10 receptor) molecules. This population persists after metabolic normalization and is especially abundant in children with high titers of auto-antibodies to glutamic acid decarboxylase and with elevated HbA1c values. These findings highlight striking differences between pediatric and adult type 1 diabetes, indicate prolonged large-scale perturbations in the CD8(+) T cell compartment in the former, and suggest that CD8(+)CD45RA(-) T cells co-expressing effector and regulatory factors are of interest as biomarkers in pediatric type 1 diabetes.

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.

Variations at multiple genes improve interleukin 28B genotype predictive capacity for response to therapy against hepatitis C infection

OBJECTIVE

To identify genetic factors that predict sustained virological response (SVR) to pegylated interferon (Peg-IFN)/ribavirin (RBV) in HIV/hepatitis C virus (HCV) genotype 1 or 4-coinfected patients and that enhance the predictive capacity of IL28B genotype in this population.

DESIGN

Prospective cohort study.

SETTING

Five tertiary care centers in Spain.

PATIENTS

Two hundred and five HIV/HCV genotype 1 or 4-coinfected patients who received a complete course of Peg-IFN/RBV for 48 weeks.

MAIN OUTCOME MEASURES

All individuals were genotyped for 144 single-nucleotide polymorphisms (SNPs).

RESULTS

One hundred and sixty-two (79%) patients bore HCV genotype 1. Overall SVR was achieved by 73 (36%) individuals. SNPs at the following genes were associated with SVR: IL28B, low-density lipoprotein receptor (LDLR), transforming growth factor β (TGF-β), aquaporine 2 (AQP-2), very-low-density lipoprotein receptor, Sp110 nuclear body protein, interferon alpha/beta receptor 1, 2'-5'-oligoadenylate synthase 1 and apolipoprotein B. There was a strong synergy between SNPs at IL28B, TGF-β and AQP-2 genes: the number of patients reaching SVR with all three favorable genotypes versus unfavorable genotypes were 22 (78.6%) versus 1 (7.1%) (P = 2.1 × 10). HCV baseline viral load, IL28B, TGF-β, AQP-2 and LDLR haplotypes were independently associated with SVR.

CONCLUSION

A number of genetic factors modify the predictive capacity of IL28B genotype. These can be used to identify HCV genotype 1 or 4-infected patients with a very high or a very low probability to respond to bitherapy with Peg-IFN/RBV. Predictive models based on these factors could be helpful to tailor direct acting antiviral-based therapy.

Diagnosis and treatment of acute hepatitis C virus infection

The first 6 months after exposure to hepatitis C virus (HCV) are regarded as acute hepatitis C (AHC). Two patient populations worldwide share the highest prevalence of AHC virus infection: injection drug users and HIV-positive men who have sex with men. Diagnosis of AHC is often difficult in both patient populations as the acute inflammatory phase can be clinically asymptomatic and patients at highest risk for acquiring AHC (injection drug users) tend to evade regular medical care. This article addresses similarities and differences in the epidemiology, diagnosis, and management of AHC monoinfection and coinfection.

Hepatitis C virus-specific T-cell-derived transforming growth factor beta is associated with slow hepatic fibrogenesis

Hepatitis C virus (HCV)-specific immune effector responses can cause liver damage in chronic infection. Hepatic stellate cells (HSC) are the main effectors of liver fibrosis. TGFβ, produced by HCV-specific CD8(+) T cells, is a key regulatory cytokine modulating HCV-specific effector T cells. Here we studied TGFβ as well as other factors produced by HCV-specific intrahepatic lymphocytes (IHL) and peripheral blood cells in hepatic inflammation and fibrogenesis. This was a cross-sectional study of two well-defined groups of HCV-infected subjects with slow (≤ 0.1 Metavir units/year, n = 13) or rapid (n = 6) liver fibrosis progression. HCV-specific T-cell responses were studied using interferon-gamma (IFNγ)-ELISpot ±monoclonal antibodies (mAbs) blocking regulatory cytokines, along with multiplex, enzyme-linked immunosorbent assay (ELISA) and multiparameter fluorescence-activated cell sorting (FACS). The effects of IHL stimulated with HCV-core peptides on HSC expression of profibrotic and fibrolytic genes were determined. Blocking regulatory cytokines significantly raised detection of HCV-specific effector (IFNγ) responses only in slow fibrosis progressors, both in the periphery (P = 0.003) and liver (P = 0.01). Regulatory cytokine blockade revealed HCV-specific IFNγ responses strongly correlated with HCV-specific TGFβ, measured before blockade (R = 0.84, P = 0.0003), with only a trend to correlation with HCV-specific IL-10. HCV-specific TGFβ was produced by CD8 and CD4 T cells. HCV-specific TGFβ, not interleukin (IL)-10, inversely correlated with liver inflammation (R = -0.63, P = 0.008) and, unexpectedly, fibrosis (R = -0.46, P = 0.05). In addition, supernatants from HCV-stimulated IHL of slow progressors specifically increased fibrolytic gene expression in HSC and treatment with anti-TGFβ mAb abrogated such expression.

CONCLUSION

Although TGFβ is considered a major profibrogenic cytokine, local production of TGFβ by HCV-specific T cells appeared to have a protective role in HCV-infected liver, together with other T-cell-derived factors, ameliorating HCV liver disease progression.