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Background: Transcatheter aortic valve replacement (TAVR) has become the standard-of-care treatment for a majority of patients with severe, symptomatic aortic stenosis. The postprocedural antithrombotic therapeutic management is still a topic of debate and could affect the incidence of HALT, a phenomenon which can be assessed by 4-dimensional computed tomography (4DCT)., Trial Design: The NOTION-4 trial is a randomized controlled trial comprising TAVR patients with no indication for oral anticoagulant (OAC) therapy, comparing lifelong single antiplatelet therapy (standard arm) versus early 3-month direct oral anticoagulant (DOAC) therapy followed by single antiplateletet therapy (experimental arm). The incidence of HALT and clinical endpoints will be evaluated in both groups at 3 months, 1 year and 5 years after randomization. The primary endpoint is the number of patients with at least 1 bioprosthetic aortic valve leaflet with HALT as assessed by cardiac 4DCT imaging at 1 year. The trial is powered for superiority testing and started enrollment in 2021. In total, 324 patients will be included. The last patient is expected to be enrolled by the end of 2024 and the primary endpoint is to be presented in 2026., Conclusion and Perspective: The NOTION-4 trial aims to study whether an early 3-month DOAC therapy after TAVR can result in a sustained lower incidence of HALT in transcatheter aortic valves. This trial holds the potential to give valuable insights into whether early OAC therapy should be integrated in future guidelines for post-TAVR antithrombotic therapeutic management., Trial Registration: NOTION-4, ClinicalTrials.gov ID NCT06449469, https://clinicaltrials.gov/study/NCT06449469., Competing Interests: Disclosures None reported., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Background and Aims: Transcatheter aortic valve implantation (TAVI) has become the first choice to treat older patients with severe symptomatic aortic stenosis (AS). This study aimed to compare TAVI with surgery in low-risk patients ≤75 years of age, including both tricuspid and bicuspid AS., Methods: The Nordic Aortic Valve Intervention (NOTION)-2 trial enrolled and 1:1 randomized low-risk patients aged ≤75 years with severe symptomatic AS to TAVI or surgery. The primary endpoint was a composite of all-cause mortality, stroke, or rehospitalization (related to the procedure, valve, or heart failure) at 12 months., Results: A total of 370 patients were enrolled with a mean age of 71.1 years and a median Society of Thoracic Surgeons risk score of 1.1%. A total of 100 patients had bicuspid AS. The 1-year incidence of the primary endpoint was 10.2% in the TAVI group and 7.1% in the surgery group [absolute risk difference 3.1%; 95% confidence interval (CI), -2.7% to 8.8%; hazard ratio (HR) 1.4; 95% CI, 0.7-2.9; P = .3]. Patients with TAVI, when compared to surgery, had lower risk of major bleeding and new-onset atrial fibrillation and higher risk of non-disabling stroke, permanent pacemaker implantation, and moderate or greater paravalvular regurgitation. The risk of the primary composite endpoint was 8.7% and 8.3% in patients with tricuspid AS (HR 1.0; 95% CI, 0.5-2.3) and 14.3% and 3.9% in patients with bicuspid AS (HR 3.8; 95% CI, 0.8-18.5) treated with TAVI or surgery, respectively (P for interaction = .1)., Conclusions: Among low-risk patients aged ≤75 years with severe symptomatic AS, the rate of the composite of death, stroke, or rehospitalization at 1 year was similar between TAVI and surgery. Transcatheter aortic valve implantation outcomes in young bicuspid AS patients warrant caution and should be further investigated. (NOTION-2, ClinicalTrials.gov, NCT02825134)., Trial Registration Number: ClinicalTrials.gov NCT02825134., (© The Author(s) 2024. Published by Oxford University Press on behalf of the European Society of Cardiology. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Competing Interests: Conflict of interest: A.L. is a consultant for VDyne and Shifamed. T.M. received consulting fees from JensCare Scientific. The other authors have no relationships relevant to the contents of this paper to disclose.

Background: Data on the likelihood of left ventricle (LV) recovery in patients with severe LV dysfunction and severe aortic stenosis undergoing transcatheter aortic valve implantation (TAVI) and its prognostic value are limited., Aims: We aimed to assess the likelihood of LV recovery following TAVI, examine its association with midterm mortality, and identify independent predictors of LV function., Methods: In our multicentre registry of 17 TAVI centres in Western Europe and Israel, patients were stratified by baseline LV function (ejection fraction [EF] >/≤30%) and LV response: no LV recovery, LV recovery (EF increase ≥10%), and LV normalisation (EF ≥50% post-TAVI)., Results: Our analysis included 10,872 patients; baseline EF was ≤30% in 914 (8.4%) patients and >30% in 9,958 (91.6%) patients. The LV recovered in 544 (59.5%) patients, including 244 (26.7%) patients whose LV function normalised completely (EF >50%). Three-year mortality for patients without severe LV dysfunction at baseline was 29.4%. Compared to this, no LV recovery was associated with a significant increase in mortality (adjusted hazard ratio 1.32; p<0.001). Patients with similar LV function post-TAVI had similar rates of 3-year mortality, regardless of their baseline LV function. Three variables were associated with a higher likelihood of LV recovery following TAVI: no previous myocardial infarction (MI), estimated glomerular filtration rate >60 mL/min, and mean aortic valve gradient (mAVG) (expressed either as a continuous variable or as a binary variable using the standard low-flow, low-gradient aortic stenosis [AS] definition)., Conclusions: LV recovery following TAVI and the extent of this recovery are major determinants of midterm mortality in patients with severe AS and severe LV dysfunction undergoing TAVI. Patients with no previous MI and those with an mAVG >40 mmHg show the best results following TAVI, which are at least equivalent to those for patients without severe LV dysfunction. (ClinicalTrials.gov: NCT04031274).

Encouraged by randomized controlled trials demonstrating non-inferiority of transfemoral transcatheter aortic valve implantation (TAVI) compared to surgical aortic valve replacement (SAVR) across all surgical risk categories, there has been a dramatic increase in the use of TAVI in a younger patient cohort with severe aortic stenosis, endorsed by both European and American Cardiac Societies. However, the standard use of TAVI in younger, less co-morbid patients with a longer life expectancy can only be supported if there is sound data demonstrating long-term durability of transcatheter aortic valves (TAVs). In this article, we have reviewed available randomized and observational registry clinical data pertaining to TAV long-term durability, placing emphasis on trials and registries using the new standardized definitions of bioprosthetic valve dysfunction (BVD) and bioprosthetic valve failure (BVF). Despite inherent difficulties in interpreting the available data, the determination reached is that the risk of structural valve deterioration (SVD) is potentially lower after TAVI than SAVR at 5 to 10 years, and that the two treatment modalities have a similar risk of BVF. This supports the adoption of TAVI in younger patients evident in current practice. However, the routine use of TAVI in younger patients with bicuspid aortic valve stenosis should be cautioned due to insufficient long-term TAV durability data in this particular patient population. Finally, we highlight the importance of future research into the unique potential mechanisms that can potentially contribute to TAV degeneration., Competing Interests: GB, LS and ODB received institutional research grants and consulting fees from Abbott, Boston Scientific, and Medtronic. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (© 2023 Montarello, Willemen, Tirado-Conte, Travieso, Bieliauskas, Sondergaard and De Backer.)

Wilms' tumor protein 1 (WT1) is a tumor-associated antigen overexpressed in various cancers. As a self-antigen, negative selection reduces the number of WT1-specific T cell receptors (TCRs). Here, we provide a protocol to generate WT1 37-45 -specific TCRs using healthy human peripheral blood mononuclear cells. We describe the expansion of WT1-specific T cell clones by two consecutive in vitro stimulations with autologous WT1 37-45 -pulsed dendritic cells and peripheral blood lymphocytes. We then detail the detection with human leukocyte antigen/WT1 37-45 tetramers., Competing Interests: Declaration of interests The authors declare no competing interests., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

Transcatheter aortic valve implantation (TAVR) is the first therapeutic option for elderly patients with severe symptomatic aortic stenosis, and indications are steadily expanding to younger patients and subjects with lower surgical risk and longer life expectancy. Commissural alignment between native and transcatheter valves facilitates coronary access after TAVR and is thus considered a procedural goal, allowing long-term management of coronary artery disease. Moreover, commissural alignment may potentially have a positive impact on transvalvular hemodynamic and valve durability. This review focus on technical hints to achieve commissural alignment and current evidence for different transcatheter aortic valves.

Background: Antegrade wiring using only antegrade guiding catheter without contralateral injection (defined as "blind antegrade wiring") may represent a valid initial treatment strategy for selected chronic coronary total occlusions (CTOs) due to the potentially lower risk of vascular complications. A careful selection of lesions eligible for this strategy as well as an accurate balance between the likelihood of success and failure is paramount. The aim of the study is to determine the rate of successful revascularization, the potential predictors of failure and the incidence of major complications, when using a "blind antegrade wiring" technique., Methods: In this multicentric study, consecutive patients with CTO undergoing percutaneous coronary intervention (PCI) were retrospectively screened. All cases approached using "blind antegrade wiring" technique were included., Results: Out of 155 consecutive CTO-PCIs, 94 involved initial "blind antegrade wiring" strategy. Successful revascularization by means of "blind antegrade wiring" technique was achieved in 73 (78%) patients. Final successful revascularization was obtained in 19 of the remaining 21 procedures with "blind antegrade wiring" failure using other techniques (by adding a second contralateral guiding catheter; 98% total successful revascularization). Logistic regression analysis identified higher J-CTO Score as the only predictor of "blind antegrade wiring" failure. One complication occurred (wire-based coronary perforation)., Conclusions: "Blind antegrade wiring" may be considered as initial strategy for selected CTO-PCI, mainly for CTOs with low J-CTO Score. This strategy would allow in a substantial number of cases to avoid a priori dual injection, keeping it as secondary strategy in case of "blind antegrade wiring" failure.

Background: Transcatheter aortic valve implantation (TAVI) has been adopted as an alternative to surgery in severe aortic stenosis treatment, even in low-intermediate risk. The aim of this study is to retrospectively report our single-centre 13-year TAVI experience with emphasis on learning curve, referral indication and trends in outcomes over time., Methods: We included 361 consecutive patients who underwent TAVI from January 2008 to December 2020, grouped according to similar per-year volume of procedures: G1 (2008-2014), G2 (2015-2017) and G3 (2018-2020)., Results: The number of procedures increased (group size: 59 vs . 106 vs . 196). No major differences were observed in STS-PROM and EuroSCORE-II between groups, despite TAVI in patients with prior surgical revascularisation was mainly performed in G1. Trans-femoral approach raised from 80.8 to 93.4%, while the most common alternative access was trans-subclavian. The pre-dilation rate was higher in G1 with lower prosthesis post-dilation rate. The length of hospital stay decreased in time by 30%. At 30 days a reduction in all-cause mortality, vascular complications, bleedings and para-valvular leak combined with higher rate of permanent pacing were observed over the groups. At 1-year there was no difference in all-cause mortality but over 30% reduction in cardiovascular death (8.5 vs. 7.5 vs. 5.6%)., Conclusions: Favourable trends were observed across the groups, with an improvement in periprocedural outcomes and cardiovascular mortality at 1-year. These improvements could depend on increased expertise because mortality reduction was noted only after reaching a significant procedure volume. A trend towards lower risk patients selection was present in our cohort, as previously described worldwide.

Objectives: We aimed to assess which bifurcation technique performs best in unprotected left-main (LM) percutaneous coronary intervention (PCI)., Background: Provisional stenting was considered the preferred technique for LM bifurcation PCI due to the supposed lower risks of thrombosis and restenosis. However, recent studies showed potential advantages of double kissing (DK)-crush technique over the other strategies., Methods: We performed a frequentist network meta-analysis comparing different stenting techniques in the setting of LM bifurcation. PubMed, Embase, the Cochrane Central Register of Controlled Trials, and Clinicaltrials.gov were searched. Both randomized clinical trials and non-randomized clinical trials were considered eligible for inclusion. Incidence rate ratios (IRRs) were computed using a random-effects model for death, cardiac death, myocardial infarction, target-vessel revascularization, target-lesion revascularization, and stent thrombosis, including 95% confidence intervals (CIs)., Results: A total of 10 studies (2364 patients) were included. Compared with provisional stenting, DK-crush was associated with fewer cardiac deaths (IRR, 0.34; 95% CI, 0.17-0.70; P<.01), myocardial infarctions (IRR, 0.19; 95% CI, 0.08-0.44; P<.001), stent thromboses (IRR, 0.31; 95% CI, 0.14-0.69; P<.01), target-vessel revascularizations (IRR, 0.25; 95% CI, 0.14-0.46; P<.001), and target-lesion revascularizations (IRR, 0.25; 95% CI, 0.14-0.46; P<.001). DK-crush was also associated with a lower risk of myocardial infarction (IRR, 0.19; 95% CI, 0.05-0.76; P=.02) when compared with standard crush and lower risk of target-lesion revascularization when compared with culotte (IRR, 0.32; 95% CI, 0.12-0.83; P=.02) and crush (IRR, 0.07; 95% CI, 0.02-0.28; P<.001)., Conclusions: DK-crush is the best technique for unprotected LM bifurcation PCI.

Targeting and exploiting the immune system has become a valid alternative to conventional options for treating cancer and infectious disease. Dendritic cells (DCs) take a central place given their role as key orchestrators of immunity. Therapeutic vaccination with autologous DCs aims to stimulate the patient's own immune system to specifically target his/her disease and has proven to be an effective form of immunotherapy with very little toxicity. A great amount of research in this field has concentrated on engineering these DCs through ribonucleic acid (RNA) to improve vaccine efficacy and thereby the historically low response rates. We reviewed in depth the 52 clinical trials that have been published on RNA-engineered DC vaccination, spanning from 2001 to date and reporting on 696 different vaccinated patients. While ambiguity prevents reliable quantification of effects, these trials do provide evidence that RNA-modified DC vaccination can induce objective clinical responses and survival benefit in cancer patients through stimulation of anti-cancer immunity, without significant toxicity. Succinct background knowledge of RNA engineering strategies and concise conclusions from available clinical and recent preclinical evidence will help guide future research in the larger domain of DC immunotherapy., Competing Interests: The authors declare no conflict of interest. The funders had no role in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results.

Prognosis of glioblastoma remains dismal, underscoring the need for novel therapies. Immunotherapy is generating promising results, but requires combination strategies to unlock its full potential. We investigated the immunomodulatory capacities of poly(I:C) on primary human glioblastoma cells and its combinatorial potential with programmed death ligand (PD-L) blockade. In our experiments, poly(I:C) stimulated expression of both PD-L1 and PD-L2 on glioblastoma cells, and a pro-inflammatory secretome, including type I interferons (IFN) and chemokines CXCL9, CXCL10, CCL4 and CCL5. IFN-β was partially responsible for the elevated PD-1 ligand expression on these cells. Moreover, real-time PCR and chloroquine-mediated blocking experiments indicated that poly(I:C) triggered Toll-like receptor 3 to elicit its effect. Cocultures of poly(I:C)-treated glioblastoma cells with peripheral blood mononuclear cells enhanced lymphocytic activation (CD69, IFN-γ) and cytotoxic capacity (CD107a, granzyme B). Additional PD-L1 blockade further propagated immune activation. Besides activating immunity, poly(I:C)-treated glioblastoma cells also doubled the attraction of CD8 + T cells, and to a lesser extent CD4 + T cells, via a mechanism which included CXCR3 and CCR5 ligands. Our results indicate that by triggering glioblastoma cells, poly(I:C) primes the tumor microenvironment for an immune response. Secreted cytokines allow for immune activation while chemokines attract CD8 + T cells to the front, which are postulated as a prerequisite for effective PD-1/PD-L1 blockade. Accordingly, additional blockade of the concurrently elevated tumoral PD-L1 further reinforces the immune activation. In conclusion, our data proposes poly(I:C) treatment combined with PD-L1 blockade to invigorate the immune checkpoint inhibition response in glioblastoma.

Success of dendritic cell (DC) therapy in treating malignancies is depending on the DC capacity to attract immune effector cells, considering their reciprocal crosstalk is partially regulated by cell-contact-dependent mechanisms. Although critical for therapeutic efficacy, immune cell recruitment is a largely overlooked aspect regarding optimization of DC vaccination. In this paper we have made a head-to-head comparison of interleukin (IL)-15-cultured DCs and conventional IL-4-cultured DCs with regard to their proficiency in the recruitment of (innate) immune effector cells. Here, we demonstrate that IL-4 DCs are suboptimal in attracting effector lymphocytes, while IL15 DCs provide a favorable chemokine milieu for recruiting CD8+ T cells, natural killer (NK) cells and gamma delta (γδ) T cells. Gene expression analysis revealed that IL-15 DCs exhibit a high expression of chemokines involved in antitumor immune effector cell attraction, while IL-4 DCs display a more immunoregulatory profile characterized by the expression of Th2 and regulatory T cell-attracting chemokines. This is confirmed by functional data indicating an enhanced recruitment of granzyme B+ effector lymphocytes by IL-15 DCs, as compared to IL-4 DCs, and subsequent superior killing of tumor cells by the migrated lymphocytes. Elevated CCL4 gene expression in IL-15 DCs and lowered CCR5 expression on both migrated γδ T cells and NK cells, led to validation of increased CCL4 secretion by IL15 DCs. Moreover, neutralization of CCR5 prior to migration resulted in an important inhibition of γδ T cell and NK cell recruitment by IL-15 DCs. These findings further underscore the strong immunotherapeutic potential of IL-15 DCs.

We formerly demonstrated that vaccination with Wilms' tumor 1 (WT1)-loaded autologous monocyte-derived dendritic cells (mo-DCs) can be a well-tolerated effective treatment in acute myeloid leukemia (AML) patients. Here, we investigated whether we could introduce the receptor for hyaluronic acid-mediated motility (RHAMM/HMMR/CD168), another clinically relevant tumor-associated antigen, into these mo-DCs through mRNA electroporation and elicit RHAMM-specific immune responses. While RHAMM mRNA electroporation significantly increased RHAMM protein expression by mo-DCs, our data indicate that classical mo-DCs already express and present RHAMM at sufficient levels to activate RHAMM-specific T cells, regardless of electroporation. Moreover, we found that RHAMM-specific T cells are present at vaccination sites in AML patients. Our findings implicate that we and others who are using classical mo-DCs for cancer immunotherapy are already vaccinating against RHAMM.

Background: Adoptive immunotherapy is gaining momentum to fight malignancies, whereby γδ T cells have received recent attention as an alternative cell source as to natural killer cells and αβ T cells. The advent of γδ T cells is largely due to their ability to recognize and target tumor cells using both innate characteristic and T cell receptor (TCR)-mediated mechanisms, their capacity to enhance the generation of antigen-specific T cell responses, and their potential to be used in an autologous or allogeneic setting., Methods: In this study, we explored the beneficial effect of the immunostimulatory cytokine interleukin (IL)-15 on purified γδ T cells and its use as a stimulatory signal in the ex vivo expansion of γδ T cells for adoptive transfer. The expansion protocol was validated both with immune cells of healthy individuals and acute myeloid leukemia patients., Results: We report that the addition of IL-15 to γδ T cell cultures results in a more activated phenotype, a higher proliferative capacity, a more pronounced T helper 1 polarization, and an increased cytotoxic capacity of γδ T cells. Moreover γδ T cell expansion starting with peripheral blood mononuclear cells from healthy individuals and acute myeloid leukemia patients is boosted in the presence of IL-15, whereby the antitumor properties of the γδ T cells are strengthened as well., Conclusions: Our results support the rationale to explore the use of IL-15 in clinical adoptive therapy protocols exploiting γδ T cells.

A growing body of evidence points toward an important anti-cancer effect of bisphosphonates, a group of inexpensive, safe, potent, and long-term stable pharmacologicals that are widely used as osteoporosis drugs. To date, they are already used in the prevention of complications of bone metastases. Because the bisphosphonates can also reduce mortality in among other multiple myeloma, breast, and prostate cancer patients, they are now thoroughly studied in oncology. In particular, the more potent nitrogen-containing bisphosphonates have the potential to improve prognosis. The first part of this review will elaborate on the direct and indirect anti-tumoral effects of bisphosphonates, including induction of tumor cell apoptosis, inhibition of tumor cell adhesion and invasion, anti-angiogenesis, synergism with anti-neoplastic drugs, and enhancement of immune surveillance (e.g., through activation of γδ T cells and targeting macrophages). In the second part, we shed light on the current clinical position of bisphosphonates in the treatment of hematological and solid malignancies, as well as on ongoing and completed clinical trials investigating the therapeutic effect of bisphosphonates in cancer. Based on these recent data, the role of bisphosphonates is expected to further expand in the near future outside the field of osteoporosis and to open up new avenues in the treatment of malignancies., (Copyright © 2015 Elsevier Inc. All rights reserved.)

First described in the 1970s, dendritic cells (DC) are currently subjects of intense investigation to exploit their unique antigen-presenting and immunoregulatory capacities. In cancer, DC show promise to elicit or amplify immune responses directed against cancer cells by activating natural killer (NK) cells and tumor antigen-specific T cells. Wilms' tumor 1 (WT1) protein is a tumor-associated antigen that is expressed in a majority of cancer types and has been designated as an antigen of major interest to be targeted in clinical cancer immunotherapy trials. In this chapter, we describe the generation, cryopreservation, and thawing of clinical grade autologous monocyte-derived DC vaccines that are loaded with WT1 by messenger RNA (mRNA) electroporation. This in-house-developed transfection method gives rise to presentation of multiple antigen epitopes and can be used for all patients without restriction of human leukocyte antigen (HLA) type.

In cancer immunotherapy, the use of dendritic cell (DC)-based vaccination strategies can improve overall survival, but until now durable clinical responses remain scarce. To date, DC vaccines are designed primarily to induce effective T-cell responses, ignoring the antitumor activity potential of natural killer (NK) cells. Aiming to further improve current DC vaccination outcome, we engineered monocyte-derived DC to produce interleukin (IL)-15 and/or IL-15 receptor alpha (IL-15Rα) using mRNA electroporation. The addition of IL-15Rα to the protocol, enabling IL-15 transpresentation to neighboring NK cells, resulted in significantly better NK-cell activation compared to IL-15 alone. Next to upregulation of NK-cell membrane activation markers, IL-15 transpresentation resulted in increased NK-cell secretion of IFN-γ, granzyme B and perforin. Moreover, IL-15-transpresenting DC/NK cell cocultures from both healthy donors and acute myeloid leukemia (AML) patients in remission showed markedly enhanced cytotoxic activity against NK cell sensitive and resistant tumor cells. Blocking IL-15 transpresentation abrogated NK cell-mediated cytotoxicity against tumor cells, pointing to a pivotal role of IL-15 transpresentation by IL-15Rα to exert its NK cell-activating effects. In conclusion, we report an attractive approach to improve antitumoral NK-cell activity in DC-based vaccine strategies through the use of IL-15/IL-15Rα mRNA-engineered designer DC.

Dendritic cell (DC) vaccination has demonstrated potential in clinical trials as a new effective cancer treatment, but objective and durable clinical responses are confined to a minority of patients. Interferon (IFN)-α, a type-I IFN, can bolster anti-tumor immunity by restoring or increasing the function of DCs, T cells and natural killer (NK) cells. Moreover, type-I IFN signaling on DCs was found to be essential in mice for tumor rejection by the innate and adaptive immune system. Targeted delivery of IFN-α by DCs to immune cells could boost the generation of anti-tumor immunity, while avoiding the side effects frequently associated with systemic administration. Naturally circulating plasmacytoid DCs, major producers of type-I IFN, were already shown capable of inducing tumor antigen-specific T cell responses in cancer patients without severe toxicity, but their limited number complicates their use in cancer vaccination. In the present work, we hypothesized that engineering easily generated human monocyte-derived mature DCs to secrete IFN-α using mRNA electroporation enhances their ability to promote adaptive and innate anti-tumor immunity. Our results show that IFN-α mRNA electroporation of DCs significantly increases the stimulation of tumor antigen-specific cytotoxic T cell as well as anti-tumor NK cell effector functions in vitro through high levels of IFN-α secretion. Altogether, our findings mark IFN-α mRNA-electroporated DCs as potent inducers of both adaptive and innate anti-tumor immunity and pave the way for clinical trial evaluation in cancer patients.

The contribution of natural killer (NK) cells to the treatment efficacy of dendritic cell (DC)-based cancer vaccines is being increasingly recognized. Much current efforts to optimize this form of immunotherapy are therefore geared towards harnessing the NK cell-stimulatory ability of DCs. In this study, we investigated whether generation of human monocyte-derived DCs with interleukin (IL)-15 followed by activation with a Toll-like receptor stimulus endows these DCs, commonly referred to as "IL-15 DCs", with the capacity to stimulate NK cells. In a head-to-head comparison with "IL-4 DCs" used routinely for clinical studies, IL-15 DCs were found to induce a more activated, cytotoxic effector phenotype in NK cells, in particular in the CD56bright NK cell subset. With the exception of GM-CSF, no significant enhancement of cytokine/chemokine secretion was observed following co-culture of NK cells with IL-15 DCs. IL-15 DCs, but not IL-4 DCs, promoted NK cell tumoricidal activity towards both NK-sensitive and NK-resistant targets. This effect was found to require cell-to-cell contact and to be mediated by DC surface-bound IL-15. This study shows that DCs can express a membrane-bound form of IL-15 through which they enhance NK cell cytotoxic function. The observed lack of membrane-bound IL-15 on "gold-standard" IL-4 DCs and their consequent inability to effectively promote NK cell cytotoxicity may have important implications for the future design of DC-based cancer vaccine studies.

Although cancer vaccination has yielded promising results in patients, the objective response rates are low. The right choice of adjuvant might improve the efficacy. Here, we review the biological rationale, as well as the preclinical and clinical results of polyinosinic:polycytidylic acid and its derivative poly-ICLC as cancer vaccine adjuvants. These synthetic immunological danger signals enhanced vaccine-induced anti-tumor immune responses and contributed to tumor elimination in animal tumor models and patients. Supported by these results, poly-ICLC-containing cancer vaccines are currently extensively studied in the ongoing trials, making it highly plausible that poly-ICLC will be part of the future approved cancer immunotherapies., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Cervarix™ is approved as a preventive vaccine against infection with the human papillomavirus (HPV) strains 16 and 18, which are causally related to the development of cervical cancer. We are the first to investigate in vitro the effects of this HPV vaccine on interleukin (IL)-15 dendritic cells (DC) as proxy of a naturally occurring subset of blood DC, and natural killer (NK) cells, two innate immune cell types that play an important role in antitumour immunity. Our results show that exposure of IL-15 DC to the HPV vaccine results in increased expression of phenotypic maturation markers, pro-inflammatory cytokine production and cytotoxic activity against HPV-positive tumour cells. These effects are mediated by the vaccine adjuvant, partly through Toll-like receptor 4 activation. Next, we demonstrate that vaccine-exposed IL-15 DC in turn induce phenotypic activation of NK cells, resulting in a synergistic cytotoxic action against HPV-infected tumour cells. Our study thus identifies a novel mode of action of the HPV vaccine in boosting innate immunity, including killing of HPV-infected cells by DC and NK cells., (© 2014 The Authors. Journal of Cellular and Molecular Medicine published by John Wiley & Sons Ltd and Foundation for Cellular and Molecular Medicine.)

Owing to their professional antigen-presenting capacity and unique potential to induce tumor antigen-specific T cell immunity, dendritic cells (DCs) have attracted much interest over the past decades for therapeutic vaccination against cancer. Clinical trials have shown that the use of tumor antigen-loaded DCs in cancer patients is safe and that it has the potential to induce anti-tumor immunity which, in some cases, culminates in striking clinical responses. Unfortunately, in a considerable number of patients, DC vaccination is unable to mount effective anti-tumor immune responses and, if it does so, the resultant immunity is often insufficient to translate into tangible clinical benefit. This underscores the necessity to re-design and optimize the current procedures for DC vaccine manufacturing. A new generation of DC vaccines with improved potency has now become available for clinical use as a result of extensive pre-clinical research. One of the promising next-generation DC vaccine candidates are interleukin (IL)-15-differentiated DCs. In this commentary, we will compile the research data that have been obtained by our group and other groups with these so-called IL-15 DCs and summarize the evidence supporting the implementation of IL-15 DCs in DC-based cancer vaccination regimens.

As central players of the innate immune system, natural killer (NK) cells can exert direct and indirect anti-tumor effects via their cytotoxic and immune regulatory capacities, pivotal in the induction of an effective adaptive anti-tumor immune response. Hence, NK cells are considered to be important in the immune surveillance of cancer. In acute myeloid leukemia (AML) patients, however, significantly impaired NK cell functions can facilitate escape from immune surveillance and affect patient outcome. Here, we review various NK cell defects and AML evasion mechanisms to escape from NK cell-mediated immune surveillance and we discuss NK cell-related parameters as prediction factors of AML patient outcome. On the basis of these observations, novel immunotherapeutic strategies capitalizing on the potentiation of NK cell functions have emerged in AML immunotherapy, as discussed in this review. Increased knowledge on AML escape routes from NK cell immune surveillance will further aid in the design of novel NK cell-based immunotherapy approaches for the treatment of AML.

The prognosis of patients with acute myeloid leukemia (AML) remains dismal, with a 5-year overall survival rate of only 5.2% for the continuously growing subgroup of AML patients older than 65 years. These patients are generally not considered eligible for intensive chemotherapy and/or allogeneic hematopoietic stem cell transplantation because of high treatment-related morbidity and mortality, emphasizing the need for novel, less toxic, treatment alternatives. It is within this context that immunotherapy has gained attention in recent years. In this review, we focus on the use of dendritic cell (DC) vaccines for immunotherapy of AML. DC are central orchestrators of the immune system, bridging innate and adaptive immunity and critical to the induction of anti-leukemic immunity. We discuss the rationale and basic principles of DC-based therapy for AML and review the clinical experience that has been obtained so far with this form of immunotherapy for patients with AML.

Interferon-α (IFN-α), a type I IFN, is a well-known antitumoral agent. The investigation of its clinical properties in acute myeloid leukemia (AML) has been prompted by its pleiotropic antiproliferative and immune effects. So far, integration of IFN-α in the therapeutic arsenal against AML has been modest in view of the divergent results of clinical trials. Recent insights into the key pharmacokinetic determinants of the clinical efficacy of IFN along with advances in its pharmaceutical formulation, have sparked renewed interest in its use. This paper reviews the possible applicability of IFN-α in the treatment of AML and provides a rational basis to re-explore its efficacy in clinical trials.