T-Cell immune activation in children with vertically transmitted hepatitis C virus infection

Direct-acting antiviral therapy enhances total CD4+ and CD8+ T-cells responses, but does not alter T-cells activation among HCV mono-infected, and HCV/HIV-1 co-infected patients

AIM

Chronic immune activation and poor T-cell immune response are strongly associated with disease progression and pathogenesis of both hepatitis C virus (HCV) and human immunodeficiency virus (HIV)-1 infections. Little is known about the impact of anti-HCV Interferon (IFN)-free direct-acting antiviral (DAA) therapy on the systemic T-cells activation and patterns of peripheral T-cells producing pro-inflammatory cytokines.

PATIENTS AND METHODS

Forty-five subjects including 18 HCV mono-infected, 17 HCV/HIV-1 co-infected patients under antiretroviral therapy (ART), and 10 healthy controls (HCs) were recruited. Blood samples were collected at baseline (T0) and 12 weeks after the end of DAA therapy (T1). Cell phenotypes (CD3, CD4, CD8), activation markers (CD38 and HLA-DR), and frequency of IFN-γ, interleukin (IL)-17, and IL-22 producing CD4+ and CD8+ T-cells were measured by flow cytometry. Plasma levels of related cytokines were also measured by enzyme-linked immunosorbent assay (ELISA).

RESULTS

Both HCV, and HCV/HIV-1 patients before and after therapy, showed significant higher percentages of any T-cell subset expressing CD38 and/or HLA-DR compared to HCs. No differences were observed in T-cells activation at T1 compared to T0 in patient groups, and when HCV patients were compared to HCV/HIV-1 group (P>0.05). After therapy, the potential of total circulating T helper (Th) and T cytotoxic (Tc) cells producing IFN-γ, IL-17, and IL-22 were increased. Plasma level of IFN-γ at baseline was showed difference compared to HCs, and significantly reduced after therapy (P<0.05).

CONCLUSION

Total T-cells immune response enhances after therapy, however, the state of immune activation may remain elevated for a longtime after the end of treatment and contribute to post-Sustained Virologic Response (SVR) consequences.

CD4+ and CD8+ T Cell Activation in Children with Hepatitis C

OBJECTIVES

To assess if peripheral T cell populations in children with chronic hepatitis C virus (HCV) infection would show evidence of activation/exhaustion and an attenuated functional response.

STUDY DESIGN

Compared with adults, children with HCV infection have a higher rate of spontaneous viral clearance. In adults, chronic HCV has been linked to T cell exhaustion. Little is known of the immune status of children with HCV. Peripheral blood mononuclear cells were isolated from 16 children with HCV (6 males, 10 females; mean age 8.6 years, range 2-17), 16 age- and sex-matched control children without HCV infection, and 20 adults with chronic HCV. Multiparameter flow cytometry was performed to characterize T cell differences across the 3 groups.

RESULTS

Controls and children with HCV had similar levels of CD4(+), CD8(+), and γδ(+) T cells. Children with HCV demonstrated a decrease in naïve T cells compared with control children and increased activation/exhaustion marker expression on both CD8(+) and CD4(+) T cells. Transcription factor analysis suggested functional activation of T cells in children with HCV; however, only the CD4(+) subset had enhanced cytokine production (interferon gamma and interleukin-2) compared with control children.

CONCLUSIONS

The HCV response in children is characterized by several changes in T cell phenotype. Many of these changes, such as increased T cell expression of programmed cell death-1, are similar to responses in adults. Of note, cytokine production by CD4(+) helper T cells is increased in children with HCV compared with age- and sex-matched control children, which may influence long-term prognosis in children with HCV.

HCV coinfection does not alter the frequency of regulatory T cells or CD8+ T cell immune activation in chronically infected HIV+ Chinese subjects

Regulatory T cell (Treg) is a subset of CD4(+) T cells that play a critical role in regulating the immune responses. Human immunodeficiency virus (HIV) infection is associated with T cell abnormalities and alters effector T cell function. There are a large number of patients coinfected with HIV and hepatitis C virus (HCV). Here, we evaluated the proportion of CD4(+) Treg cells expressing CD25 and FOXP3, and the status of immune activation of CD8(+) T cells in 60 Chinese patients chronically infected with HIV and/or HCV. Furthermore, we investigated the influence of highly active antiretroviral therapy (HAART) on the level of Treg cells and immune activated CD8(+) T cells. We observed that the Treg level was upregulated in HIV infection and HCV infection could not enhance this kind of upregulation significantly. The level of Treg cells was negatively correlated with CD4(+) T cell counts and positively correlated with HIV viral loads. We observed considerably elevated CD38 and HLA-DR expression in CD8(+) T cells in HIV-infected subjects but not in HCV-infected patients in comparison to that in healthy controls. There is no significant difference concerning the proportion of CD8(+) T cells expressing CD38 or HLA-DR between HIV-1-monoinfected and HIV/HCV-coinfected patients. After 12-week HAART, the proportion of Treg cells dropped, but still more than the level in healthy controls. HAART could reverse the abnormal immune activation of CD8(+) T cells. The decrease of Tregs did not alter the downregulation of HIV-1-specific CTL responses in these HIV-infected patients after HAART therapy. The level of HIV virus might be the key point for the decline of CTL responses.

Could a loss of memory T cells limit responses to hepatitis C virus (HCV) antigens in blood leucocytes from patients chronically infected with HCV before and during pegylated interferon-alpha and ribavirin therapy?

The proportions and activation status of T cells may influence responses to hepatitis C virus (HCV) and treatment outcome in patients receiving pegylated interferon (IFN)-alpha/ribavirin therapy. We confirmed that IFN-gamma enzyme-linked immunospot (ELISPOT) responses to HCV are poor in HCV patients and showed that responses to HCV and cytomegalovirus (CMV) antigens decrease during therapy. This was most apparent in patients with sustained virological response (SVR). Baseline frequencies of CD4+ effector memory (TEM) T cells were lower in SVR than non-SVR. Proportions of CD4+ and CD8+ TEM and terminally differentiated effector memory (TEMRA) T cells declined on therapy in SVR, as did proportions of Fas+ CD8+ TEMRA T cells. Baseline frequencies of programmed death (PD)-1-expressing CD4+ TEM and TEMRA T-cells were higher in SVR. Therapy increased percentages of PD-1+ CD4+ central memory (TCM) T cells and PD-1+ CD8+ TEM and TEMRA T cells in SVR. We conclude that successful therapy depletes circulating antigen-specific CD4+ T cell responses. This paralleled decreases in proportions of effector memory T cells and higher percentages of CD4+ TCM T cells expressing PD-1.

Age-related lymphocyte and neutrophil levels in children of hepatitis C-infected women

BACKGROUND

Investigation of immunologic values in children vertically exposed to hepatitis C virus (HCV) infection could help explain the higher risk of infection in girls and indicate mechanisms of spontaneous viral clearance and possible long-term immunologic effects.

METHODS

Prospective study of children born to HCV-infected women. Lymphocyte and neutrophil measurements were age-standardized using the LMS method (this summarizes the changing age distribution of a variable). Associations between maternal and infant characteristics and lymphocyte and neutrophil z-scores were quantified using linear regression allowing for repeated measures.

RESULTS

HCV-infected children, girls, and those born to HCV/human immunodeficiency virus (HIV)-coinfected women had significantly higher lymphocyte z-scores than HCV-uninfected children, boys, and children born to HCV-only-infected women, respectively. Peak absolute lymphocytes were significantly lower for infected children with evidence of viral clearance than for persistently infected children. Girls also had significantly higher neutrophil z-scores than boys but HCV-infected children had significantly lower neutrophil z-scores than uninfected children.

CONCLUSIONS

The gender associations are in line with those observed among children born to HIV-infected women, suggesting general gender-based differences in response to infection. Age-related standards for uninfected children could be used to assess immune function in other pediatric diseases and these results suggest that gender-specific reference values should be used at least for the first 2 years of life.

Modifications of T-lymphocyte subsets before and during interferon and ribavirin treatment for chronic hepatitis C infection

Our purpose was to determine in HCV-infected patients whether T-lymphocyte sub-populations were modified before and during interferon-alpha and ribavirin treatment, and whether this correlated with virological response. Twenty-two naive patients were given IFN-alpha 3 Million Units three times per week for 24 or 48 weeks and ribavirin. Sustained virological response corresponded to undetectable serum HCV RNA at treatment completion and 6 months later. Total blood lymphocyte counts and CD3(+)CD4(+), CD3(+)CD8(+), CD3(+)CD4(+)HLA-DR(+), and CD3(+)CD8(+)HLA-DR(+) lymphocyte subsets evaluated before, during, and after treatment were compared to values from 37 healthy subjects. At inclusion, patients and controls had similar total lymphocyte counts. CD3(+)CD4(+) counts and percentages were significantly higher in HCV patients. HLA-DR expression was also increased in CD4(+) (p < 0.0001) and CD8(+) T-cells (p = 0.0008) as compared with controls. During treatment, all lymphocyte subset counts and percentage decreased except the CD3(+)CD4(+) T-cell percentage which increased. Moreover, after 1 month of treatment, virological responders exhibited higher CD4(+) counts than nonresponders (p = 0.025), whereas they did not differ at inclusion or during the 2nd to 6th months of treatment. After treatment completion, all populations returned to baseline values. These results suggest that CD3(+)CD4(+) T-lymphocyte percentage increase under treatment could be related to IFN immunomodulation and associated with virological response.

Ultrastructure characteristics of HCV infected human trophoblast cells in culture

AIM: To investigate whether the cultured trophoblastic cells can be infected with hepatitis C virus (HCV) and observe the ultrastructural features of infected cells.

METHODS: Human placentae were digested with trypsin and then centrifuged with percoll density gradient to obtain trophoblastic cells, and then incubated in HCV positive serum. The HCV RNA in HCV infected syncytiotroblasts was quantitated with RT-PCR. Ultrastructural characteristics of infected syncytiotroblasts were observed with transmission electron microscope.

RESULTS: HCV RNA was detected in supernatant of the cultured medium during 40 day periods of incubation. The antibody of HCV NS5 was observed around the nucleus with confocal microscope. The Ultrastructure of infected throphotoblast cells differed obviously from that of normal cells, and manifested with hyperplasia of lysosomes and rough endoplasmic, appearance of vacuoles and virus-like particles, and decreased lipid droplets.

CONCLUSION: Trophoblastic cells could be infected by HCV, and the cellular ultrastructure changed dramatically following infection of HCV.