Comprehensive analysis of the alpha-fetoprotein-specific CD8+ T cell responses in patients with hepatocellular carcinoma

Cell-mediated immune responses to alpha-fetoprotein and other antigens in hepatocellular carcinoma

Cell-mediated immune responses play an important role in the control of tumour growth. CD4 and CD8 T cells recognise tumour antigens presented via major histocompatibility complex molecules of antigen presenting cells and develop into effector cells with the ability to identify and kill tumour cells. Here, we re-examine the adaptive immune response to tumour antigens expressed by hepatocellular carcinoma (HCC) and discuss approaches that could be applied in future T-cell-based immunotherapy schedules to induce a potent and effective antitumour immunity. Moreover, we discuss cytotoxic T lymphocyte and Th1 responses to tumour antigens in patients with HCC and evaluate the effects of conventional treatments on antitumour T-cell responses.

Enhancement of tumor-specific T-cell responses by transcatheter arterial embolization with dendritic cell infusion for hepatocellular carcinoma

Transcatheter arterial embolization (TAE) destroys a tumor by the induction of necrosis and/or apoptosis and causes inflammation with cytokine production, which may favor immune activation and presentation of tumor-specific antigens. In the current study, we attempted to identify the effect of TAE on tumor-specific T-cell responses and the additional effect of dendritic cell (DC) infusion performed during TAE. The prevalence of tumor antigen-specific T cells was determined by interferon-gamma enzyme-linked immunospot analysis using alpha-fetoprotein (AFP) and tumor antigen-derived peptides in 20 and 13 patients with hepatocellular carcinoma (HCC) who received TAE and TAE with DC infusion, respectively. The increased frequency of AFP-specific T cells was observed in 6 of 20 patients after TAE. It was observed more frequently in patients with DC infusion than in those with TAE alone. However, tumor recurrence was not completely prevented in patients albeit displayed enhanced immune responses. The evidence that the enhanced immune responses were transient and attenuated within 3 months was provided in time-course analysis. In conclusion, TAE with DC infusion enhances the tumor-specific immune responses more effectively than TAE alone. Although the effect is not sufficient to prevent HCC recurrence, these results may contribute to the development of novel immunotherapeutic approach for HCC.

HCV drug discovery aimed at viral eradication

Hepatitis C virus (HCV) causes significant morbidity and mortality worldwide with nearly 3% of the world population infected by this virus. Fortunately, this virus does not establish latency, and hence it may be possible to eradicate it. HCV is strongly associated with liver cirrhosis and hepatocellular carcinoma and is currently treated with pegylated interferon-alpha (peg-IFN-alpha) and ribavirin. Unfortunately, these limited treatment options often produce significant side effects, and currently, complete eradication of virus with combined drug modalities has not yet been achieved for the majority of chronically HCV-infected individuals. Restricted treatment options, lack of a universal cure for HCV and the link between chronic infection, liver cirrhosis and hepatocellular carcinoma necessitate design of novel drugs and treatment options. Understanding the relationship between the immune response, viral clearance and inhibition of viral replication with pharmacology-based design can ultimately allow for complete eradication of HCV. This review focuses upon significant novel preclinical and clinical specifically targeted antiviral therapy (STAT-C) drugs under development, highlights their mechanism of action, and discusses their impact on systemic viral loads and permanent clearance of infection.

Expansion of anti-AFP Th1 and Tc1 responses in hepatocellular carcinoma occur in different stages of disease

Background:

α-Fetoprotein (AFP) is a tumour-associated antigen in hepatocellular carcinoma (HCC) and is a target for immunotherapy. However, there is little information on the pattern of CD4 (Th1) and CD8 (Tc1) T-cell response to AFP in patients with HCC and their association with the clinical characteristics of patients.

Methods:

We therefore analysed CD4 and CD8 T-cell responses to a panel of AFP-derived peptides in a total of 31 HCC patients and 14 controls, using an intracellular cytokine assay for IFN-γ.

Results:

Anti-AFP Tc1 responses were detected in 28.5% of controls, as well as in 25% of HCC patients with Okuda I (early tumour stage) and in 31.6% of HCC patients with stage II or III (late tumour stages). An anti-AFP Th1 response was detected only in HCC patients (58.3% with Okuda stage I tumours and 15.8% with Okuda stage II or III tumours). Anti-AFP Th1 response was mainly detected in HCC patients who had normal or mildly elevated serum AFP concentrations (P=0.00188), whereas there was no significant difference between serum AFP concentrations in these patients and the presence of an anti-AFP Tc1 response. A Th1 response was detected in 44% of HCC patients with a Child–Pugh A score (early stage of cirrhosis), whereas this was detected in only 15% with a B or C score (late-stage cirrhosis). In contrast, a Tc1 response was detected in 17% of HCC patients with a Child–Pugh A score and in 46% with a B or C score.

Conclusion:

These results suggest that anti-AFP Th1 responses are more likely to be present in patients who are in an early stage of disease (for both tumour stage and liver cirrhosis), whereas anti-AFP Tc1 responses are more likely to be present in patients with late-stage liver cirrhosis. Therefore, these data provide valuable information for the design of vaccination strategies against HCC.

A new staging system is more discriminant than conventional staging systems for unresectable hepatocellular carcinoma

BACKGROUND

Prediction of the life expectancy of a patient with unresectable hepatocellular carcinoma (HCC) remains difficult. The aims of the study were to construct a new staging scheme for patients with unresectable HCC and to compare the discriminatory ability of the staging scheme with the Okuda and CLIP score and TNM staging system in a cohort of patients with unresectable HCC.

METHODS

A retrospective analysis of unresectable HCC cases from 1999 to 2003 was performed. The Cox model was used for multivariate analyses. The final model was derived from 10 randomly chosen training samples and the prognostic validity of the new staging scheme was assessed on the corresponding testing samples. Moreover, 54 cases with unresectable HCC were enrolled and prospectively followed up. The new staging, named the China integrated score (CIS), Okuda, TNM and CLIP systems were determined for each case. Comparisons of the survival rate between each stage were performed to evaluate their discriminatory ability.

RESULTS

A simple scoring system was constructed, assigning linear scores (0/1/2) to the three covariates (TNM, alpha-fetoprotein and Child-Pugh) of the final model. The CIS system was more discriminant than the Okuda or TNM staging system, as confirmed by the Kaplan-Meier comparison of survival curves and by the Cox's regression analysis, with a median survival rate of 9.0, 2.3, 2.1 and 0.6 months in patients with CIS 2, 3, 4 and 5, respectively. The CIS system was performed as well as the CLIP score.

CONCLUSION

The new staging system, accounting for both liver function and tumor characteristics, can accurately identify patients with different prognoses, particularly in the advanced phases of HCC. It should be useful as the only tool that can be applied for patients with unresectable HCC.

Profile of tumor antigen-specific CD8 T cells in patients with hepatitis B virus-related hepatocellular carcinoma

BACKGROUND & AIMS

Tumor and viral antigens are expressed by hepatocellular carcinoma (HCC) in patients with chronic hepatitis B, but little is known about the immunodominance and function of tumor- and virus-specific CD8+ T cells in these patients.

METHODS

HLA-A2-restricted T-cell responses to 16 tumor antigens and hepatitis B virus (HBV) proteins were tested using 49 previously described epitopes. Cells from 30 HLA-A2+, HBV-infected patients (10 with HCC, 10 with HBV cirrhosis, and 10 HBV but no cirrhosis) were analyzed, after expansion, by enzyme-linked immunosorbent spot (ELISPOT). Interferon (IFN)-gamma, tumor necrosis factor (TNF)-alpha, and interleukin (IL)-2 production, as well as expression of the degranulation marker CD107a on tumor-specific CD8+ T cells, were evaluated.

RESULTS

Cells from all groups had tumor-specific responses. The tumor antigens NY-ESO-1 and SSX-2 were most frequently targeted and were immunogenic in the HLA-A2 subtypes that are characteristic of Asian ethnicity. Tumor-specific T cells had low affinities; T cells from non-HCC patients were polyfunctional (IFN-gamma+, TNF-alpha+, CD107a+) and those from HCC patients displayed an exhausted phenotype (IFN-gamma+, CD107a+). Programmed Death 1 (PD-1) was expressed at higher levels on T cells from tumor and liver than peripheral blood from HCC patients and might contribute to T-cell exhaustion. Blocking PD-1/PD-L1 increased the frequency of tumor-specific T cells in HCC patients but did not restore T cell function.

CONCLUSIONS

Patients with or without HCC have a quantitative and functional hierarchy of tumor-specific T cells. HLA-A2-restricted T cells from HCC patients target NY-ESO-1, but exist in an exhausted state that might require additional activation to restore function.