PEG-IFN alpha but not ribavirin alters NK cell phenotype and function in patients with chronic hepatitis C

Impending HCC diagnosis in patients with cirrhosis after HCV cure features a natural killer cell signature

BACKGROUND AND AIMS

The risk of developing HCC in chronically infected patients with AQ2 HCV with liver cirrhosis is significantly elevated. This risk remains high even after a sustained virological response with direct-acting antivirals. To date, disease-associated signatures of NK cells indicating HCC development are unclear.

APPROACH AND RESULTS

This study investigated NK cell signatures and functions in 8 cohorts covering the time span of HCC development, diagnosis, and onset. In-depth analysis of NK cell profiles from patients with cirrhosis who developed HCC (HCV-HCC) after sustained virological response compared with those who remained tumor-free (HCV-noHCC) revealed increasingly dissimilar NK cell signatures over time. We identified expression patterns with persistently high frequencies of TIM-3 and CD38 on NK cells that were largely absent in healthy controls and were associated with a high probability of HCC development. Functional assays revealed that the NK cells had potent cytotoxic features. In contrast to HCV-HCC, the signature of HCV-noHCC converged with the signature found in healthy controls over time. Regarding tissue distribution, single-cell sequencing showed high frequencies of these cells in liver tissue and the invasive margin but markedly lower frequencies in tumors.

CONCLUSIONS

We show that HCV-related HCC development has profound effects on the imprint of NK cells. Persistent co-expression of TIM-3hi and CD38 + on NK cells is an early indicator for HCV-related HCC development. We propose that the profiling of NK cells may be a rapid and valuable tool to assess the risk of HCC development in a timely manner in patients with cirrhosis after HCV cure.

Interferon-based treatment of chronic hepatitis D

Treatment of hepatitis D virus (HDV) infection has been based on the administration of interferon-alfa for more than three decades. First studies to treat HDV-infected patients with type 1 interferons were already performed in the 1980s. Several smaller trials and case series were reported thereafter. During the mid 2000s the use of pegylated interferons for hepatitis D was established. Since then, additional trials were performed in different countries exploring strategies to personalize treatment including extended treatment durations. The overall findings were that about one-quarter to one-third of patients benefit from interferon treatment with persistent suppression of HDV replication. However, only few patients achieve also functional cure of hepatitis B with HBsAg loss. Importantly, several studies indicate that successful interferon treatment is associated with improved clinical long-term outcomes. Still, only a proportion of patients with hepatitis D can be treated with interferons. Even though alternative treatments are currently developed, it is likely that pegylated interferon-alfa will still have an important role in the management of hepatitis D - either alone or in combination. Therefore, better biomarkers are needed to select patients with a high likelihood to benefit from interferon-based treatments. In this review we are discussing basic principles of mode of action of interferon alpha against HDV, summarize previous data on interferon treatment of hepatitis D and give an outlook on potential combinations with novel drugs currently in development.

Immunomodulation of Natural Killer Cell Function by Ribavirin Involves TYK-2 Activation and Subsequent Increased IFN-γ Secretion in the Context of In Vitro Hepatitis E Virus Infection

Hepatitis E virus (HEV) is a major cause of acute hepatitis globally. Chronic and fulminant courses are observed especially in immunocompromised transplant recipients since administration of ribavirin (RBV) does not always lead to a sustained virologic response. By in vitro stimulation of NK cells through hepatoma cell lines inoculated with a full-length HEV and treatment with RBV, we analyzed the viral replication and cell response to further elucidate the mechanism of action of RBV on immune cells, especially NK cells, in the context of HEV infection. Co-culture of HEV-infected hepatoma cells with PBMCs and treatment with RBV both resulted in a decrease in viral replication, which in combination showed an additive effect. An analysis of NK cell functions after stimulation revealed evidence of reduced cytotoxicity by decreased TRAIL and CD107a degranulation. Simultaneously, IFN-ɣ production was significantly increased through the IL-12R pathway. Although there was no direct effect on the IL-12R subunits, downstream events starting with TYK-2 and subsequently pSTAT4 were upregulated. In conclusion, we showed that RBV has an immunomodulatory effect on the IL-12R pathway of NK cells via TYK-2. This subsequently leads to an enhanced IFN-ɣ response and thus, to an additive antiviral effect in the context of an in vitro HEV infection.

High Number and Specific Comorbidities Could Impact the Immune Response in COVID-19 Patients

BACKGROUND

Cellular immunodeficiency and comorbidities are common in COVID-19 patients.

AIM

The purpose of this study was to investigate comorbidities impacting on the cellular immunity in COVID-19 patients.

METHODS

The research objects included 55 healthy controls and 718 COVID-19 patients who divided into the control group and the COVID-19 group, respectively. Those in the COVID-19 group were divided into subgroups on the basis of the number and types of comorbidities present. Lymphocyte itself and its subsets were compared between the control group and the COVID-19 group, the groups with comorbidities based on the different number and types of comorbidities, and the relationship between the lymphocyte counts and subsets with the number and types of comorbidities was investigated.

RESULTS

Compared with the control group, the lymphocyte counts and T cell subsets were significantly increased in the groups with comorbidities, but both B and NK cell subsets were significantly decreased in the no comorbidity group and in most of the groups with comorbidities (all P<0.05). In the three comorbidities group, the lymphocyte counts and T cell subsets were all significantly decreased, but the CD56+ percentage was obviously increased (all P<0.05). The number of comorbidities was negatively correlated with the lymphocyte counts and the T and NK cell subsets. A negative correlation also existed between cancer and both the lymphocyte counts and the T cell subsets, between chronic hepatitis B and the lymphocyte counts, and between chronic kidney disease and the CD3+ counts. A positive correlation existed between nonalcoholic fatty liver disease (NAFLD) disease and both lymphocyte and CD3+ counts. The risk factors were number of comorbidities for the lymphocyte count, CD3+CD4+ and CD3+CD8+ percentages, NAFLD for the lymphocyte and CD3+ counts, cardiovascular diseases for CD3+CD4+ and CD3+CD8+ percentages, diabetes mellitus for the CD3+CD8+ percentage, and cancer for the CD3+ percentage, respectively.

CONCLUSIONS

High numbers of comorbidities and specific comorbidities could impact the immune response of COVID-19 patients. This study provides a reference for clinicians in the identification of suitable and timely immunotherapy for COVID-19 patients.

CLINICAL TRIAL REGISTRY

https://www.chictr.org.cn/enindex.aspx, identifier ChiCTR2000034563.

Safety, Immune, and Antiviral Effects of Pegylated Interferon Alpha 2b Administration in Antiretroviral Therapy-Suppressed Individuals: Results of Pilot Clinical Trial

In the pilot NCT01935089 trial, we tested whether pegylated interferon alpha2b (Peg-IFN-α2b) with antiretroviral therapy (ART) was safe and could impact HIV and immune measures in blood and in gut-associated lymphoid tissue (GALT). Twenty HIV-1⁺ ART-suppressed individuals received 1 μg/kg/week Peg-IFN-α2b with ART for 20 weeks, with intermediate 4-week analytical ART interruption (ATI). Safety, immune activation, HIV viral load and integrated HIV DNA in blood, and HIV RNA and DNA in gut biopsies were measured. A total of 7/20 participants experienced grade 3-4 adverse events, while 17/20 participants completed the study. Of the 17 participants who completed the study, 8 remained suppressed during ATI, while all 17 were suppressed at end of treatment (EoT). As expected, treatment increased activation of T and natural killer (NK) cells and IFN-stimulated molecule expression on monocytes in periphery. While circulating CD4⁺ T cells showed a trend for a decrease in integrated HIV DNA, GALT showed a significant decrease in HIV-1 RNA⁺ cells as measured by in situ hybridization along with a reduction in total HIV DNA and cell-associated RNA by EoT. The observed decrease in HIV-1 RNA⁺ cells in GALT was positively associated with the decrease in activated NK cells and macrophages. This study documents for the first time that 20 weeks of immunotherapy with Peg-IFN-α2b+ART (inclusive of a 4-week ATI) is safe and results in an increase in blood and GALT immune activation and in a significant decrease in HIV-1 RNA⁺ cells in GALT in association with changes in innate cell activation.

Direct antiviral agents upregulate natural killer cell potential activity in chronic hepatitis C patients

Direct antiviral agents (DAAs) can eliminate hepatitis C virus rapidly and make chronic hepatitis C (CHC) curable. The changes in the innate immune system during treatment with DAAs are still in dispute. To investigate how the functions of natural killer (NK) cells change during and after treatment with DAAs in each NK cell subset. Thirteen CHC patients were treated with sofosbuvir/ledipasvir, and the expression levels of NKp46 and NKG2A were tested via flow cytometry at baseline, at 2, 4, 8 and 12 weeks during the therapy and 12 and 24 weeks after the end of treatment; expression levels were compared between CHC patients and 13 healthy controls. A redirected killing assay was used to detect the cytotoxicity of NK cells. After coculturing NK cells with JFH-Huh7 cells for 72 h, HCV RNA was tested to analyze the inhibition ability of NK cells. All patients achieved sustained virologic response. The expression of the activating receptor NKp46 was decreased first at week 8 during therapy with DAAs and then increased and normalized to levels in healthy controls after treatment with DAAs. The expression of the inhibitory receptor NKG2A was decreased during and after treatment with DAAs. Each NK cell subset has a similar changing trend during and after treatment with DAAs, although some differences can be found earlier and later. The ratio of NKp46 and NKG2A was upregulated after treatment with DAAs. CD56bright NK cells have less amplitude in the frequency ratio changes after treatment with DAAs. The coculture results showed that both the specific lysis and the inhibition of HCV replication were significantly upregulated after treatment with DAAs. DAA treatments can affect patients' NK cell function. After DAA treatments, the expression of functional markers is downregulated, but the potential activity of NK cells is upregulated. The function of NK cells is normalized to levels in healthy controls. CD56bright NK cells play an important role in this process.

Recovery of natural killer cells is mainly in post-treatment period in chronic hepatitis C patients treated with sofosbuvir plus ledipasvir

AIM

To investigate how natural killer (NK) cells are affected in the elimination of hepatitis C virus (HCV) by sofosbuvir/ledipasvir, two highly effective direct-acting antivirals (DAAs).

METHODS

Thirteen treatment-naïve and treatment-experienced chronic hepatitis C (CHC) patients were treated with sofosbuvir/ledipasvir, and NK cells were detected at baseline, weeks 2, 4, 8 and 12 during therapy, and week post of treatment (Pt)-12 and 24 after the end of therapy by multicolor flow cytometry and compared with those from 13 healthy controls.

RESULTS

All patients achieved sustained virological response. There was a significant decline in CD56bright NK cell frequencies at week 8 (P = 0.002) and week 12 (P = 0.003), which were altered to the level comparable to healthy controls at week Pt-12, but no difference was observed in the frequency of CD56dim NK cells. Compared with healthy controls, the expression levels of NKG2A, NKp30 and CD94 on NK cells from CHC patients at baseline were higher. NKG2A, NKp30 and CD94 started to recover at week 12 and reached the levels similar to those of healthy controls at week Pt-12 or Pt-24. Before treatment, patients have higher interferon (IFN)-γ and perforin levels than healthy controls, and IFN-γ started to recover at week 8 and reached the normalized level at week Pt-12.

CONCLUSION

NK cells of CHC patients can be affected by DAAs, and phenotypes and function of NK cells recover not at early stage but mainly after the end of sofosbuvir/ledipasvir treatment.

Type I Interferon Responses by HIV-1 Infection: Association with Disease Progression and Control

Human immunodeficiency virus type 1 (HIV-1) is the causative agent of acquired immunodeficiency syndrome and its infection leads to the onset of several disorders such as the depletion of peripheral CD4⁺ T cells and immune activation. HIV-1 is recognized by innate immune sensors that then trigger the production of type I interferons (IFN-Is). IFN-Is are well-known cytokines eliciting broad anti-viral effects by inducing the expression of anti-viral genes called interferon-stimulated genes (ISGs). Extensive in vitro studies using cell culture systems have elucidated that certain ISGs such as APOBEC3G, tetherin, SAM domain and HD domain-containing protein 1, MX dynamin-like GTPase 2, guanylate-binding protein 5, and schlafen 11 exert robust anti-HIV-1 activity, suggesting that IFN-I responses triggered by HIV-1 infection are detrimental for viral replication and spread. However, recent studies using animal models have demonstrated that at both the acute and chronic phase of infection, the role of IFN-Is produced by HIV or SIV infection in viral replication, spread, and pathogenesis, may not be that straightforward. In this review, we describe the pluses and minuses of HIV-1 infection stimulated IFN-I responses on viral replication and pathogenesis, and further discuss the possibility for therapeutic approaches.

Immune phenotype and function of natural killer and T cells in chronic hepatitis C patients who received a single dose of anti-MicroRNA-122, RG-101

MicroRNA-122 is an important host factor for the hepatitis C virus (HCV). Treatment with RG-101, an N-acetylgalactosamine-conjugated anti-microRNA-122 oligonucleotide, resulted in a significant viral load reduction in patients with chronic HCV infection. Here, we analyzed the effects of RG-101 therapy on antiviral immunity. Thirty-two chronic HCV patients infected with HCV genotypes 1, 3, and 4 received a single subcutaneous administration of RG-101 at 2 mg/kg (n = 14) or 4 mg/kg (n = 14) or received a placebo (n = 2/dosing group). Plasma and peripheral blood mononuclear cells were collected at multiple time points, and comprehensive immunological analyses were performed. Following RG-101 administration, HCV RNA declined in all patients (mean decline at week 2, 3.27 log10 IU/mL). At week 8 HCV RNA was undetectable in 15/28 patients. Plasma interferon-γ-induced protein 10 (IP-10) levels declined significantly upon dosing with RG-101. Furthermore, the frequency of natural killer (NK) cells increased, the proportion of NK cells expressing activating receptors normalized, and NK cell interferon-γ production decreased after RG-101 dosing. Functional HCV-specific interferon-γ T-cell responses did not significantly change in patients who had undetectable HCV RNA levels by week 8 post-RG-101 injection. No increase in the magnitude of HCV-specific T-cell responses was observed at later time points, including 3 patients who were HCV RNA-negative 76 weeks postdosing.

CONCLUSION

Dosing with RG-101 is associated with a restoration of NK-cell proportions and a decrease of NK cells expressing activation receptors; however, the magnitude and functionality of ex vivo HCV-specific T-cell responses did not increase following RG-101 injection, suggesting that NK cells, but not HCV adaptive immunity, may contribute to HCV viral control following RG-101 therapy. (Hepatology 2017;66:57-68).

Complementary Effects of Interleukin-15 and Alpha Interferon Induce Immunity in Hepatitis B Virus Transgenic Mice

In chronic hepatitis B (CHB), failure to control hepatitis B virus (HBV) is associated with T cell dysfunction. HBV transgenic mice mirror many features of the human disease, including T cell unresponsiveness, and thus represent an appropriate model in which to test novel therapeutic strategies. To date, the tolerant state of CD8⁺ T cells in these animals could be altered only by strong immunogens or by immunization with HBV antigen-pulsed dendritic cells; however, the effectors induced were unable to suppress viral gene expression or replication. Because of the known stimulatory properties of alpha interferon (IFN-α) and interleukin-15 (IL-15), this study explored the therapeutic potential of liver-directed gene transfer of these cytokines in a murine model of CHB using adeno-associated virus (AAV) delivery. This combination not only resulted in a reduction in the viral load in the liver and the induction of an antibody response but also gave rise to functional and specific CD8⁺ immunity. Furthermore, when splenic and intrahepatic lymphocytes from IFN-α- and IL-15-treated animals were transferred to new HBV carriers, partial antiviral immunity was achieved. In contrast to previous observations made using either cytokine alone, markedly attenuated PD-L1 induction in hepatic tissue was observed upon coadministration. An initial study with CHB patient samples also gave promising results. Hence, we demonstrated synergy between two stimulating cytokines, IL-15 and IFN-α, which, given together, constitute a potent approach to significantly enhance the CD8⁺ T cell response in a state of immune hyporesponsiveness. Such an approach may be useful for treating chronic viral infections and neoplastic conditions.

IMPORTANCE With 350 million people affected worldwide and 600,000 annual deaths due to HBV-induced liver cirrhosis and/or hepatocellular carcinoma, chronic hepatitis B (CHB) is a major health problem. However, current treatment options are costly and not very effective and/or need to be administered for life. The unprecedented efficacy of the strategy described in our paper may offer an alternative and is relevant for a broad spectrum of readers because of its clear translational importance to other chronic viral infections in which a hyporesponsive antigen-specific T cell repertoire prevents clearance of the pathogen.

A Novel Toll-Like Receptor 9 Agonist, MGN1703, Enhances HIV-1 Transcription and NK Cell-Mediated Inhibition of HIV-1-Infected Autologous CD4+ T Cells

Toll-like receptor (TLR) agonists are potent enhancers of innate antiviral immunity and may also reverse HIV-1 latency. Therefore, TLR agonists have a potential role in the context of a "shock-and-kill" approach to eradicate HIV-1. Our extensive preclinical evaluation suggests that a novel TLR9 agonist, MGN1703, may indeed perform both functions in an HIV-1 eradication trial. Peripheral blood mononuclear cells (PBMCs) from aviremic HIV-1-infected donors on antiretroviral therapy (ART) that were incubated with MGN1703 ex vivo exhibited increased secretion of interferon alpha (IFN-α) (P= 0.005) and CXCL10 (P= 0.0005) in culture supernatants. Within the incubated PBMC pool, there were higher proportions of CD69-positive CD56(dim)CD16(+)NK cells (P= 0.001) as well as higher proportions of CD107a-positive (P= 0.002) and IFN-γ-producing (P= 0.038) NK cells. Incubation with MGN1703 also increased the proportions of CD69-expressing CD4(+)and CD8(+)T cells. Furthermore, CD4(+)T cells within the pool of MGN1703-incubated PBMCs showed enhanced levels of unspliced HIV-1 RNA (P= 0.036). Importantly, MGN1703 increased the capacity of NK cells to inhibit virus spread within a culture of autologous CD4(+)T cells assessed by using an HIV-1 p24 enzyme-linked immunosorbent assay (ELISA) (P= 0.03). In conclusion, we show that MGN1703 induced strong antiviral innate immune responses, enhanced HIV-1 transcription, and boosted NK cell-mediated suppression of HIV-1 infection in autologous CD4(+)T cells. These findings support clinical testing of MGN1703 in HIV-1 eradication trials.

IMPORTANCE

We demonstrate that MGN1703 (a TLR9 agonist currently undergoing phase 3 clinical testing for the treatment of metastatic colorectal cancer) induces potent antiviral responses in immune effector cells from HIV-1-infected individuals on suppressive antiretroviral therapy. The significantly improved safety and tolerability profiles of MGN1703 versus TLR9 agonists of the CpG-oligodeoxynucleotide (CpG-ODN) family are due to its novel "dumbbell-shape" structure made of covalently closed, natural DNA. In our study, we found that incubation of peripheral blood mononuclear cells with MGN1703 results in natural killer cell activation and increased natural killer cell function, which significantly inhibited the spread of HIV in a culture of autologous CD4(+)T cells. Furthermore, we discovered that MGN1703-mediated activation can enhance HIV-1 transcription in CD4(+)T cells, suggesting that this molecule may serve a dual purpose in HIV-1 eradication therapy: enhanced immune function and latency reversal. These findings provide a strong preclinical basis for the inclusion of MGN1703 in an HIV eradication clinical trial.

Improvement of liver function parameters in advanced HCV-associated liver cirrhosis by IFN-free antiviral therapies

BACKGROUND

Successful antiviral treatment of decompensated hepatitis B with HBV polymerase inhibitors is associated with improvement of liver function. To what extent liver function also improves in cirrhotic patients with chronic hepatitis C receiving novel interferon-free (IFN-free) therapies is unknown.

AIM

To study liver function in cirrhotic HCV patients receiving IFN-free therapies.

METHODS

We here studied 80 consecutive patients with advanced HCV associated liver cirrhosis including 34 patients (43%) with Child B/C cirrhosis and 42 patients (53%) with platelet counts of <90.000/μL receiving different combinations of direct acting antivirals without interferon [sofosbuvir/ribavirin (n = 56), sofosbuvir/simeprevir ± ribavirin (n = 15) and sofosbuvir/daclatasvir ± ribavirin (n = 9)]. The majority of patients was infected with HCV genotype 1 (n = 50); HCV genotypes 2, 3 and 4 were present in 4, 24 and 2 patients, respectively.

RESULTS

Liver function parameters including albumin, bilirubin, cholinesterase and prothrombin time all improved in the majority of patients during antiviral therapy irrespectively of the underlying HCV genotype, however, with different kinetics. MELD scores improved until post-treatment week 12 in 44% of the patients but worsened in 15%. A sustained virological response was achieved in 63% of the patients. HCV RNA relapse led to moderate ALT increases in 15/23 patients but was not associated with hepatic decompensations.

CONCLUSION

This real-world single centre study showed that interferon-free treatment of hepatitis C patients with advanced liver cirrhosis restores liver function, and may thereby reduce the need for liver transplantations.

Altered effector functions of NK cells in chronic hepatitis C are associated with IFNL3 polymorphism

Interferon α-mediated effector functions of NK cells may contribute to the control of HCV replication and the pathogenesis of liver disease. The single-nucleotide polymorphism rs12979860 near IFNL3 (previously known as IL28B) is important in response to IFN-α treatment and in spontaneous resolution of acute hepatitis C. The role of the IFNL3 polymorphism in NK cell function is unclear. Thus, we investigated the role of IFNL3 polymorphism in type I IFN-dependent regulation of NK cell functions in patients with cHC and healthy control subjects. We demonstrated a marked polarization of NK cells toward cytotoxicity in response to IFN-α stimulation in patients with hepatitis C. That TRAIL up-regulation was present, particularly in patients with the IFNL3-TT allele, was supported by a shift in the pSTAT-1:pSTAT-4 ratios toward pSTAT-1. In patients bearing the IFNL3-TT allele, NK cell effector function correlated with liver disease activity. In contrast, higher cytokine production of NK cells was observed in healthy individuals with the IFNL3-CC genotype, which may support spontaneous HCV clearance in acute infection. Overall, these findings show that the role of NK cells may differ in chronic infection vs. early antiviral defense and that the IFNL3 genotype differentially influences NK cell function.

Immunological Analysis During Interferon-Free Therapy for Chronic Hepatitis C Virus Infection Reveals Modulation of the Natural Killer Cell Compartment

BACKGROUND

Chronic hepatitis C virus (HCV) infection is a global health problem, resulting in liver failure, hepatocellular carcinoma, and liver-related death. Natural killer (NK) cells are innate immune cells, and their activity is known to correlate to viral treatment response of HCV. In this study, we investigate the immune effects of viral load decline with direct-acting antivirals (DAAs) in blood.

METHODS

Twelve patients with chronic HCV were treated with asunaprevir and daclatasvir, and peripheral blood was analyzed at various time points during therapy.

RESULTS

In line with previous studies, we confirmed restoration of HCV-specific T-cell frequency upon viral load decline. In addition, we show that serum interferon (IFN)-γ inducible-protein 10, interleukin (IL)-12p40, and IL-18 levels decreased early after start of therapy. Surface expression of activation receptors NKp30, NKp46, and inhibitory receptor NKG2A on blood NK cells reduced during therapy. In addition, the expression of TRAIL on NK cells was reduced during IFN-free therapy, suggesting a decrease in TRAIL-mediated killing by NK cells.

CONCLUSIONS

We show that viral load decline as a consequence of treatment with novel DAAs in chronic HCV patients reduces serum levels of NK cell-stimulating cytokines and causes correction of the altered NK cell phenotype observed in chronic HCV patients.

CLINICAL TRIALS REGISTRATION

NCT02282709.

Natural Killer Cell Characteristics in Patients With Chronic Hepatitis B Virus (HBV) Infection Are Associated With HBV Surface Antigen Clearance After Combination Treatment With Pegylated Interferon Alfa-2a and Adefovir

BACKGROUND

The role of natural killer (NK) cells in the process of hepatitis B virus (HBV) surface antigen (HBsAg) clearance and whether their phenotype is related to treatment outcome in patients with chronic hepatitis B are currently unknown.

METHODS

Patients with chronic hepatitis B (HBV DNA load, >17 000 IU/mL) were treated with pegylated interferon alfa-2a and adefovir for 48 weeks. NK cell phenotype and function were analyzed in 7 responders (defined as individuals with HBsAg clearance by week 72; 3 HBV e antigen [HBeAg]-positive and 4 HBeAg-negative), 7 matched nonresponders, and 7 healthy controls. Subsequently, 34 baseline samples from HBeAg-positive patients with chronic hepatitis B were analyzed.

RESULTS

During treatment, the percentage and absolute number of CD56(bright) NK cells increased significantly, whereas the percentage and absolute number of CD56(dim) NK cells decreased. At baseline, responders had a significantly lower expression of chemokine receptor CX3CR1 on CD56(bright) NK cells and inhibitory receptor NKG2A on CD56(dim) NK cells, compared with nonresponders. In addition, responders had higher CD56(bright) TRAIL expression and interferon γ production at end of treatment. These baseline differences were not found in HBeAg-positive patients who had HBeAg seroconversion without HBsAg clearance.

CONCLUSIONS

Combination therapy significantly influences NK cell phenotype and function. Differences between patients with chronic hepatitis B with HBsAg clearance and nonresponders suggest that NK cells play a role in the clearance of HBsAg during interferon-based combination therapy.

Effective induction of melanoma-antigen-specific CD8+ T cells via Vγ9γδT cell expansion by CD56(high+) Interferon-α-induced dendritic cells

Dendritic cells (DCs) can be differentiated from CD14+ monocytes in the presence of interferon-α (IFNα) and granulocyte/macrophage-colony stimulating factor (GM-CSF) in vitro and are known as IFN-DCs. Circulating blood CD56+ cells expressing high levels of CD14, HLA-DR and CD86 have been shown to spontaneously differentiate into DC-like cells in vitro after their isolation from blood. We show here that IFN-DCs expressing high levels of CD56 (hereafter, CD56(high+) IFN-DCs) can be differentiated in vitro from monocytes obtained as adherent cells from healthy donors and patients with metastatic melanoma. These cells expressed high levels of CD14, HLA-DR and CD86 and possessed many pseudopodia. These CD56(high+) IFN-DCs may be an in vitro counterpart of the circulating CD56+ CD14+ CD86+ HLA-DR+ cells in blood. Conventional mature DCs differentiated from monocytes as adherent cells in the presence of GM-CSF, IL-4 and TNF-α (hereafter, mIL-4DCs) did not express CD56 or CD14. In contrast to mIL-4DCs, the CD56(high+) IFN-DCs exhibited a stronger capacity to stimulate autologous CD56+ Vγ9γδT cells highly producing IFNγ in the presence of zoledronate and IL-2. The CD56(high+) IFN-DCs possessing HLA-A*0201 effectively induced Mart-1-modified melanoma peptide (A27L)-specific CD8+ T cells through preferential expansion of CD56+ Vγ9γδT cells in the presence of A27L, zoledronate and IL-2. Vaccination with CD56(high+) IFN-DCs copulsed with tumor antigens and zoledronate may orchestrate the induction of various CD56+ immune cells possessing high effector functions, resulting in strong immunological responses against tumor cells. This study may be relevant to the design of future clinical trials of CD56(high+) IFN-DCs-based immunotherapies for patients with melanoma.