Reciprocal changes of naïve and effector/memory CD8+ T lymphocytes in chronic hepatitis B virus infection

CCL19 and CCR7 Expression, Signaling Pathways, and Adjuvant Functions in Viral Infection and Prevention

Chemokine (C–C motif) ligand 19 (CCL19) is a critical regulator of the induction of T cell activation, immune tolerance, and inflammatory responses during continuous immune surveillance, homeostasis, and development. Migration of CC-chemokine receptor 7 (CCR7)-expressing cells to secondary lymphoid organs is a crucial step in the onset of adaptive immunity, which is initiated by a complex interaction between CCR7 and its cognate ligands. Recent advances in knowledge regarding the response of the CCL19-CCR7 axis to viral infections have elucidated the complex network of interplay among the invading virus, target cells and host immune responses. Viruses use various strategies to evade or delay the cytokine response, gaining additional time to replicate in the host. In this review, we summarize the impacts of CCL19 and CCR7 expression on the regulation of viral pathogenesis with an emphasis on the corresponding signaling pathways and adjuvant mechanisms. We present and discuss the expression, signaling adaptor proteins and effects of CCL19 and CCR7 as these molecules differentially impact different viral infections and viral life cycles in host homeostatic strategies. The underlying mechanisms discussed in this review may assist in the design of novel agents to modulate chemokine activity for viral prevention.

T Cell Distribution in Relation to HIV/HBV/HCV Coinfections and Intravenous Drug Use

Intravenous drug use (IDU) is one of the most important transmission routes for blood borne viruses, including human immunodeficiency virus (HIV), hepatitis B virus (HBV), and hepatitis C virus (HCV). These infections alter the subset distributions of T cells; however, knowledge of such effects during HIV, HBV, and or HCV coinfection is limited. Therefore, we aimed to evaluate any associations between T cell distribution and the presence of HIV, HBV, and HCV coinfections among persons who inject drugs (PWID). Blood samples from 88 Caucasian PWID (mean age 30; 82% male) and 47 age-matched subjects negative for all three infections (mean age of 29; 83% male) were analyzed. The T cell markers CD3, CD4, CD8, CD45RA, CCR7, HLA-DR, and CCR5 were assessed using flow cytometry. Of the PWID, 40% were HIV+HBV+HCV+, 20% HBV+HCV+, 19% HCV+, and 13% negative for all three infections. The HIV+HBV+HCV+ PWID had lower percentages of CD4⁺ and higher percentages of CD8⁺ cells compared to triple negative PWID (p < 0.001 in all cases). The only difference between HBV+HCV+ with triple negative PWID was the lower CD4⁺ cell percentages among the former (52.1% and 58.6%, p = 0.021). Triple negative PWID had higher immune activation and number of CCR5⁺ cells compared to the controls. We suggest that the altered T cell subset distribution among PWID is mainly triggered by HIV infection and or IDU, while HBV and or HCV seropositivity has minimal additional effects on CD4⁺ cell distribution.

Decreases in activated CD8+ T cells in patients with severe hepatitis B are related to outcomes

BACKGROUND

Many studies on T helper (Th)1, Th2, T regulatory and Th17 cells have been carried out in acute-on-chronic liver failure (ACLF). However, CD8(+) T cell, as a main participant in immune-mediated injuries and defense against microorganisms, has seldom been studied in ACLF.

AIMS

The purpose of this study was to investigate the CD8(+) T cell function, and the outcomes of patients with severe hepatitis [SH; serum bilirubin (SB) ≥ 10 mg/dl and prothrombin activity (PTA) < 60 %].

METHODS

Thirty-six patients with chronic HBV-associated SH were included. Twenty normal chronic hepatitis B (CHB) patients (2 < SB < 10 (mg/dl) and PTA ≥ 60 %) and 28 healthy volunteers were enrolled as control groups.

RESULTS

Twenty-six patients with SH were diagnosed with ACLF (SB ≥ 10 mg/dl and PTA ≤ 40 %). The non-recovered ACLFs (NR-ACLF) had higher HBV DNA loads than recovered ACLFs (R-ACLF) (6.03 ± 1.79 vs. 4.36 ± 1.61 (log10, IU/L)). The NR-ACLFs had the highest neutrophil:lymphocyte ratios (5.10 ± 2.37) (all P < 0.001; a = 0.05). The CHBs had higher perforin(+) and TCM (CD45RA(-)CD62L(hi)CCR7(+)) proportions [31.28 ± 19.51, 5.32 ± 3.57 (%)] compared to R-ACLFs (11.75 ± 15.35, 0.78 ± 0.76 (%); P = 0.004, 0.001, respectively), or NR-ACLFs (11.61 ± 5.79, 1.14 ± 0.67 (%); P = 0.006, 0.003). The non-ACLF SHs had higher CD38(+) proportions than R-ACLFs or NR-ACLFs (25.46 ± 8.02 vs. 16.24 ± 7.77 or 16.81 ± 6.30 (%), P = 0.039, 0.023).

CONCLUSIONS

High neutrophil:lymphocyte ratios and a decrease in activated CD8(+) T cells may be related to poor outcomes in patients with SH.

Pegylated interferon α enhances recovery of memory T cells in hepatitis B e antigen positive chronic hepatitis B patients

AIM: To investigate the change of peripheral CD8⁺ memory T lymphocyte subsets in hepatitis B e antigen positive patients with chronic hepatitis B (CHB) during peginterferon-alph 2b (PEG-IFNα-2b) treatment.

METHODS: Thirty hepatitis B e antigen positive patients with CHB were recruited and received PEG-IFNα-2b treatment for 24 wk. Before and at the 12^th and 24^th wk of treatment, flow cytometry was used to detect the peripheral CD8⁺ memory T lymphocyte subsets. Real-time PCR was used to detect the level of HBV DNA. Markers of hepatitis B virus infection were detected by ELISA assay, and serum level of alanine aminotransferase (ALT) was measured using an automatic biochemical analyzer.

RESULTS: Treatment for 24 wk with PEG-IFN-2b resulted in HBeAg seroconversion to negative in 6.7% patients, and the response rate was 36.7%. The response rate was significantly higher in patients with lower viral load (VL). At weeks 12 and 24, serum ALT levels in patients with CHB were significantly lower than pretreatment values. The level of HBV DNA and the percentage of naïve lymphocytes (T naïve) in patients with CHB at week 12 were significantly lower than pretreatment values, but there were no significant differences between at weeks 24 and 12. The percentages of central memory T cells (T_CM) and effector memory T cells (T_EM) increased gradually during PEG-IFNα-2b treatment. The levels of ALT and HBV DNA and the proportion of naïve T cells significantly decreased in the responders at 12 and 24 wk (P < 0.05), and the proportion of T_EM significantly increased at 12 and 24 wk (P < 0.05). The proportion of T_CM had no significant difference between the responders and non-responders at 12 wk (P > 0.05), but significantly increased in the responders at 24 wk (P < 0.05). T_TEM had no significant changes at different time points and in the responders.

CONCLUSION: PEG-IFNα-2b treatment enhances recovery of memory T cell subset in CHB patients by down-regulating naïve T cells and up-regulating effector cells. CD8⁺ memory T lymphocyte subsets may be used as biomarkers for predicting the outcome of treatment.

CD4+CD25+ regulatory T cells and different states of HBV infection

CD4⁺CD25⁺ regulatory T cells are a recently discovered subset of CD4⁺ T cell population that mediates immune suppression. Recent studies suggested that regulatory T cells are closely associated with the prognosis of different states of HBV infection. Here we review the types, mechanisms of action and immunophenotypes of CD4⁺CD25⁺ regulatory T cells, as well as their relationship with different states of HBV infection.

The Possible Role of TLR2 in Chronic Hepatitis B Patients with Precore Mutation

Recognition mechanisms of innate immune response help to improve immunotherapeutic strategies in HBeAg-negative chronic hepatitis B (CHB). Toll-like receptor 2 (TLR2) is an important component of innate immunity. In this study, the frequency of precore mutations of the hepatitis B virus (HBV) and serum TLR2 were evaluated in CHB patients. Fifty-one patients with chronic hepatitis B, negative for HBeAg and detectable HBV DNA, were examined for the presence of mutations in pre-core region of HBV genome by direct sequencing. Serum TLR2 was measured by enzyme-linked immunosorbent assay. Interactions of truncated HBeAg and TLR2 proteins were evaluated with molecular docking software. The G1896A pre-core mutation were detected in 29 (57%) which was significantly associated with higher concentration of serum TLR2 in comparison with patients without this mutation (4.8 ± 2.9 versus 3.4 ± 2.2 ng/mL, P = 0.03). There was also a significant correlation between serum ALT and TLR-2 (r = 0.46; P = 0.01). Docking results illustrated residues within the N-terminus of truncated HBeAg and TLR2, which might facilitate the interaction of these proteins. These findings showed the dominance of G1896A pre-core mutation of HBV variants in this community which was correlated with serum TLR2. Moreover TLR2 is critical for induction of inflammatory cytokines and therefore ALT elevation.

Changes in plasma levels of soluble E-selectin, T lymphocyte subsets and NK cells in patients with chronic HBV infection

AIM: To evaluate serum and hepatic levels of E-selectin in patients with chronic HBV infection and to analyze their relationship with T lymphocyte subsets and natural killer (NK) cells.

METHODS: Serum samples from 270 patients with chronic HBV infection, including 101 patients with chronic hepatitis, 121 with liver cirrhosis and 48 with hepatocellular carcinoma, and from 281 healthy controls, were used in this study. Circulating levels of soluble E-selectin were measured by enzyme-linked immunosorbent assay (ELISA). T lymphocyte subsets and NK cells were measured by flow cytometry (FCM). Immunohistochemistry (IHC) was used to detect the expression of E-selectin in liver tissue specimens from patients with chronic HBV infection.

RESULTS: Serum levels of soluble E-selectin were higher in patients with chronic hepatitis or liver cirrhosis than in those with hepatocellular carcinoma and healthy controls (68.94 ± 34.09, 43.39 ± 18.00 vs 16.69 ± 8.27, 13.96 ± 7.50, all P < 0.01). Immunohistochemistry analysis showed that the positive rates of E-selectin expression in endothelial cells in patients with chronic hepatitis and those with liver cirrhosis were 83.3% and 57.1% (χ² = 6.242, P = 0.012), respectively, and no positive E-selectin staining was detected in patients with hepatocellular carcinoma or healthy controls. The percentages of CD4⁺ T cells and NK cells decreased significantly in patients with chronic HBV infection than in controls (29.11 ± 6.79 vs 37.02 ± 7.05; 23.57 ± 7.33 vs 27.37 ± 7.03, both P < 0.01). The percentages of CD3⁺, CD8⁺, CD4⁺ T cells and NK cells decreased significantly in patients with liver cirrhosis or hepatocellular carcinoma than in controls (all P < 0.01). Soluble E-selectin levels were positively related to the percentages of CD3⁺ and CD8⁺ cells (r = 0.548, 0.715; both P < 0.01), but negatively related to the percentages of CD4+ cells and NK cells (r = -0.429, -0.672; both P < 0.01).

CONCLUSION: Varying degrees of immune dysfunction is present in patients with chronic HBV infection, and high expression of E-selectin is associated with the development of chronic hepatitis and liver cirrhosis. These results suggest that E-selectin can be used as a useful marker for evaluation of hepatic inflammatory activity.