The anti-tumour activity of allogeneic cytokine-induced killer cells in patients who relapse after allogeneic transplant for haematological malignancies

Ex vivo expansion of natural killer cells for hematological cancer immunotherapy: a systematic review and meta-analysis

The present systematic review aimed to investigate natural killer (NK) cell ex vivo expansion protocols within the scope of clinical trials targeting hematological cancer and to conduct a meta-analysis to assess the effect of NK cell infusion on survival. Research articles of clinical studies in which cell products produced by ex vivo expansion, consisting of a certain amount of NK cells and infused to patients with hematological cancer, were included in the systematic review. We conducted a proportion analysis with random effects for product purity and viability values. Studies having control groups were included in the survival meta-analysis. Among 11.028 identified records, 21 were included in the systematic review. We observed statistically significant heterogeneity for viability (I2 = 97.83%, p < 0.001) and purity values (I2 = 99.95%, p < 0.001), which was attributed to the diversity among isolation and expansion protocols. In addition, the survival meta-analysis findings suggested that NK cell therapy favors disease-free survival (DFS) of patients with myeloid malignancies but limited to only two clinical studies (odds ratio = 3.40 (confidence interval:1.27-9.10), p = 0.01). While included protocols yielded cell products with acceptable viability, the utility of immunomagnetic methods; feeder cells such as K562 expressing membrane-bound IL15 and 4-1BBL or expressing membrane-bound IL21 and 4-1BBL might be preferable to achieve better purity. In conclusion, NK cell therapy has a potential to improve DFS of patients with myeloid malignancies.

How can Cytokine-induced killer cells overcome CAR-T cell limits

The successful treatment of patients affected by B-cell malignancies with Chimeric Antigen Receptor (CAR)-T cells represented a breakthrough in the field of adoptive cell therapy (ACT). However, CAR-T therapy is not an option for every patient, and several needs remain unmet. In particular, the production of CAR-T cells is expensive, labor-intensive and logistically challenging; additionally, the toxicities deriving from CAR-T cells infusion, such as cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS), have been documented extensively. Alternative cellular therapy products such as Cytokine-induced killer (CIK) cells have the potential to overcome some of these obstacles. CIK cells are a heterogeneous population of polyclonal CD3+CD56+ T cells with phenotypic and functional properties of NK cells. CIK cell cytotoxicity is exerted in a major histocompatibility complex (MHC)-unrestricted manner through the engagement of natural killer group 2 member D (NKG2D) molecules, against a wide range of hematological and solid tumors without the need for prior antigen exposure or priming. The foremost potential of CIK cells lies in the very limited ability to induce graft-versus-host disease (GvHD) reactions in the allogeneic setting. CIK cells are produced with a simple and extremely efficient expansion protocol, which leads to a massive expansion of effector cells and requires a lower financial commitment compared to CAR-T cells. Indeed, CAR-T manufacturing involves the engineering with expensive GMP-grade viral vectors in centralized manufacturing facilities, whereas CIK cell production is successfully performed in local academic GMP facilities, and CIK cell treatment is now licensed in many countries. Moreover, the toxicities observed for CAR-T cells are not present in CIK cell-treated patients, thus further reducing the costs associated with hospitalization and post-infusion monitoring of patients, and ultimately encouraging the delivery of cell therapies in the outpatient setting. This review aims to give an overview of the limitations of CAR-T cell therapy and outline how the use of CIK cells could overcome such drawbacks thanks to their unique features. We highlight the undeniable advantages of using CIK cells as a therapeutic product, underlying the opportunity for further research on the topic.

Distinctive phenotype for HLA-E- versus HLA-A2-restricted memory CD8 αβT cells in the course of HCMV infection discloses features shared with NKG2C+CD57+NK and δ2-γδT cell subsets

The human cytomegalovirus (HCMV) triggers both innate and adaptive immune responses, including protective CD8⁺ αβT cells (CD8T) that contributes to the control of the infection. In addition to CD8T restricted by classical HLA class Ia molecules, HCMV also triggers CD8T recognizing peptides from the HCMV UL40 leader peptide and restricted by HLA-E molecules (HLA-E_UL40 CD8T). This study investigated the frequency, phenotype and functions of HLA-E_UL40 CD8T in comparison to the immunodominant HLA-A2_pp65 CD8T upon acute (primary or secondary infection) or chronic infection in kidney transplant recipients (KTR) and in seropositive (HCMV⁺) healthy volunteer (HV) hosts. The frequency of hosts with detected HLA-E_UL40 CD8T was similar after a primary infection (24%) and during viral latency in HCMV+ HV (26%) and equal to the frequency of HLA-A2_pp65 CD8T cells in both conditions (29%). Both CD8T subsets vary from 0.1% to >30% of total circulating CD8T according to the host. Both HLA-E_UL40 and HLA-A2_pp65 CD8T display a phenotype specific of CD8⁺ TEMRA (CD45RA⁺/CCR7^-) but HLA-E_UL40 CD8T express distinctive level for CD3, CD8 and CD45RA. Tim3, Lag-3, 4-1BB, and to a lesser extend 2B4 are hallmarks for T cell priming post-primary infection while KLRG1 and Tigit are markers for restimulated and long lived HCMV-specific CD8T responses. These cell markers are equally expressed on HLA-E_UL40 and HLA-A2_pp65 CD8T. In contrast, CD56 and PD-1 are cell markers discriminating memory HLA-E- from HLA-A2-restricted CD8T. Long lived HLA-E_UL40 display higher proliferation rate compared to HLA-A2_pp65 CD8T consistent with elevated CD57 expression. Finally, a comparative immunoprofiling indicated that HLA-E_UL40 CD8T, divergent from HLA-A2_pp65 CD8T, share the expression of CD56, CD57, NKG2C, CD158 and the lack of PD-1 with NKG2C⁺CD57+ NK and δ2^-γδT cells induced in response to HCMV and thus defines a common immunopattern for these subsets.

Impact of natural killer cells on outcomes after allogeneic hematopoietic stem cell transplantation: A systematic review and meta-analysis

Background

Natural killer (NK) cells play a vital role in early immune reconstitution following allogeneic hematopoietic stem cell transplantation (HSCT).

Methods

A literature search was performed on PubMed, Cochrane, and Clinical trials.gov through April 20, 2022. We included 21 studies reporting data on the impact of NK cells on outcomes after HSCT. Data was extracted following the PRISMA guidelines. Pooled analysis was done using the meta-package (Schwarzer et al.). Proportions with 95% confidence intervals (CI) were computed.

Results

We included 1785 patients from 21 studies investigating the impact of NK cell reconstitution post-HSCT (8 studies/1455 patients), stem cell graft NK cell content (4 studies/185 patients), therapeutic NK cell infusions post-HSCT (5 studies/74 patients), and pre-emptive/prophylactic NK cell infusions post-HSCT (4 studies/77 patients). Higher NK cell reconstitution was associated with a better 2-year overall survival (OS) (high: 77%, 95%CI 0.73-0.82 vs low: 55%, 95%CI 0.37-0.72; n=899), however, pooled analysis for relapse rate (RR) or graft versus host disease (GVHD) could not be performed due to insufficient data. Higher graft NK cell content demonstrated a trend towards a better pooled OS (high: 65.2%, 95%CI 0.47-0.81 vs low: 46.5%, 95%CI 0.24-0.70; n=157), lower RR (high: 16.9%, 95%CI 0.10-0.25 vs low: 33%, 95%CI 0.04-0.72; n=157), and lower acute GVHD incidence (high: 27.6%, 95%CI 0.20-0.36 vs low: 49.7%, 95%CI 0.26-0.74; n=157). Therapeutic NK or cytokine-induced killer (CIK) cell infusions for hematologic relapse post-HSCT reported an overall response rate (ORR) and complete response (CR) of 48.9% and 11% with CIK cell infusions and 82.8% and 44.8% with NK cell infusions, respectively. RR, acute GVHD, and chronic GVHD were observed in 55.6% and 51.7%, 34.5% and 20%, and 20.7% and 11.1% of patients with CIK and NK cell infusions, respectively. Pre-emptive donor-derived NK cell infusions to prevent relapse post-HSCT had promising outcomes with 1-year OS of 69%, CR rate of 42%, ORR of 77%, RR of 28%, and acute and chronic GVHD rates of 24.9% and 3.7%, respectively.

Conclusion

NK cells have a favorable impact on outcomes after HSCT. The optimal use of NK cell infusions post-HSCT may be in a pre-emptive fashion to prevent disease relapse.

Clinical Studies on Cytokine-Induced Killer Cells: Lessons from Lymphoma Trials

Simple Summary

Lymphoma is a heterogeneous group of neoplasms including over 70 different subtypes. Its biological characteristic of deriving from lymphoid tissues makes it ideal for immunotherapy. In this paper, we provide insights into lymphoma-specific clinical trials based on cytokine-induced killer (CIK) cell therapy. We also reviewed pre-clinical lymphoma models where CIK cells have been used along with other synergetic tumor-targeting immune modules to improve their therapeutic potential. From a broader perspective, we will highlight that CIK cell therapy has potential, and in this rapidly evolving landscape of cancer therapies its optimization (as a personalized therapeutic approach) will be beneficial in lymphomas.

Abstract

Cancer is a complex disease where resistance to therapies and relapses often pose a serious clinical challenge. The scenario is even more complicated when the cancer type itself is heterogeneous in nature, e.g., lymphoma, a cancer of the lymphocytes which constitutes more than 70 different subtypes. Indeed, the treatment options continue to expand in lymphomas. Herein, we provide insights into lymphoma-specific clinical trials based on cytokine-induced killer (CIK) cell therapy and other pre-clinical lymphoma models where CIK cells have been used along with other synergetic tumor-targeting immune modules to improve their therapeutic potential. From a broader perspective, we will highlight that CIK cell therapy has potential, and in this rapidly evolving landscape of cancer therapies its optimization (as a personalized therapeutic approach) will be beneficial in lymphomas.

A serum-free protocol for the ex vivo expansion of Cytokine-Induced Killer cells using gas-permeable static culture flasks

Cytokine-Induced (CIK) cells represent an attractive approach for cell-based immunotherapy, as they show several advantages compared with other strategies. Here we describe an original serum-free protocol for CIK cell expansion that employs G-Rex devices and compare the resulting growth, viability, phenotypic profile and cytotoxic activity with conventional culture in tissue flasks. CIK cells were obtained from buffy coats, seeded in parallel in G-Rex and tissue flasks, and stimulated with clinical-grade IFN-γ, anti-CD3 antibody and IL-2. G-Rex led to large numbers of CIK cells, with a minimal need for technical interventions, thus reducing the time and costs of culture manipulation. CIK cells generated in G-Rex showed a less differentiated phenotype, with a significantly higher expression of naive-associated markers such as CD62L, CD45RA and CCR7, which correlates with a remarkable expansion potential in culture and could lead to longer persistence and a more sustained anti-tumor response in vivo. The described procedure can be easily translated to large-scale production under Good Manufacturing Practice. Overall, this protocol has strong advantages over existing procedures, as it allows easier, time-saving and cost-effective production of CIK effector cells, fostering their clinical application.

UV Light-inactivated HSV-1 Stimulates Natural Killer Cell-induced Killing of Prostate Cancer Cells

Herein we demonstrate that ultraviolet light-inactivated Herpes Simplex Virus-1 (UV-HSV-1) stimulates peripheral blood mononuclear cells (PBMCs) to lyse both androgen-sensitive and androgen-independent prostate cancer (PrCA) cell lines, but not the benign prostatic hyperplastic epithelial cell line, BPH-1, and is 1000-10,000-fold more potent at stimulating this killing than ultraviolet light-inactivated Vesicular Stomatitis Virus, adenovirus, reovirus or cytomegalovirus. Among PBMCs, natural killer (NK) cells appear to be a major cell type involved in this killing and UV-HSV-1 appears to directly and potently stimulate NK cell expression of CD69, degranulation, cytokine production, and migration to IL-8 in PC3 conditioned medium. We also found that UV-HSV-1 stimulates glycolysis in PBMCs and NK cells, and that 2-deoxyglucose and the protein kinase C inhibitor, Go6976, and the NFκB inhibitor, Bay 11-7082, all abrogate UV-HSV-1 activated killing of PC3 cells by PBMCs and NK cells. Using neutralizing anti-Toll-like receptor 2 (TLR2) we found that UV-HSV-1, like HSV-1, activates NK cells via TLR2. Taken together, these results are consistent with Toll-like receptor 2 ligands on UV-HSV-1 stimulating TLR2 on NK cells to activate protein kinase C, leading to enhanced glycolysis and NFκB activation, both of which play a critical role in this anti-PrCA innate immune response. Importantly, UV-HSV-1 synergizes with IL-15 to increase the cytolytic activity of PBMCs against PC3 cells and there was considerable donor-to-donor variation in killing ability. These results support the preclinical development of UV-HSV-1 as an adjuvant, in combination with IL-15, for cell infusions of healthy, preselected NK cells to treat PrCA.

Adoptive cell therapy of triple negative breast cancer with redirected cytokine-induced killer cells

Cytokine-Induced Killer (CIK) cells share several functional and phenotypical properties of both T and natural killer (NK) cells. They represent an attractive approach for cell-based immunotherapy, as they do not require antigen-specific priming for tumor cell recognition, and can be rapidly expanded in vitro. Their relevant expression of FcγRIIIa (CD16a) can be exploited in combination with clinical-grade monoclonal antibodies (mAbs) to redirect their lytic activity in an antigen-specific manner. Here, we report the efficacy of this combined approach against triple negative breast cancer (TNBC), an aggressive tumor that still requires therapeutic options. Different primitive and metastatic TNBC cancer mouse models were established in NSG mice, either by implanting patient-derived TNBC samples or injecting MDA-MB-231 cells orthotopically or intravenously. The combined treatment consisted in the repeated intratumoral or intravenous injection of CIK cells and cetuximab. Tumor growth and metastasis were monitored by bioluminescence or immunohistochemistry, and survival was recorded. CIK cells plus cetuximab significantly restrained primitive tumor growth in mice, either in patient-derived tumor xenografts or MDA-MB-231 cell line models. Moreover, this approach almost completely abolished metastasis spreading and dramatically improved survival. The antigen-specific mAb favored tumor and metastasis tissue infiltration by CIK cells, and led to an enrichment of the CD16a⁺ subset.

Data highlight the potentiality of this novel immunotherapy strategy where a nonspecific cytotoxic cell population can be converted into tumor-specific effectors with clinical-grade antibodies, thus providing not only a therapeutic option for TNBC but also a valid alternative to more complex approaches based on chimeric antigen receptor-engineered cells.

List of abbreviations

ACT, Adoptive Cell Transfer; ADCC, Antibody-Dependent Cell-mediated Cytotoxicity; ADP, Adenosine diphosphate; BLI, Bioluminescence Imaging; CAR, Chimeric Antigen Receptor; CIK, Cytokine Induced Killer cells; CTX, Cetuximab; DMEM, Dulbecco’s Modified Eagle Medium; EGFR, Human Epidermal Growth Factor 1; ER, Estrogen; FBS, Fetal Bovine Serum; FFPE, Formalin-Fixed Paraffin-Embedded; GMP, Good Manufacturing Practices; GVHD, Graft Versus Host Disease; HER2, Human Epidermal Growth Factor 2; HRP, Horseradish Peroxidase; IFN-γ, Interferon-γ; IHC, Immunohistochemistry; IL-2, Interleukin-2; ISO, Irrelevant antibody; i.t., intratumoral; i.v., intravenous, mAbs, Monoclonal Antibodies; mIHC, Multiplex Fluorescence Immunohistochemistry; MHC, Major Histocompatibility Complex; NK, Natural Killer; NKG2D, Natural-Killer group 2 member D; NSG, NOD/SCID common γ chain knockout; PARP, Poly ADP-ribose polymerase; PBMCs, Peripheral Blood Mononuclear Cells; PBS, Phosphate-buffered saline; PDX, Patient-derived xenograft; PR, Progesterone; rhIFN-γ, Recombinant Human Interferon-γ; RPMI, Roswell Park Memorial Institute; STR, Short tandem Repeat; TCR, T Cell Receptor; TNBC, Triple Negative Breast Cancer; TSA, Tyramide Signal Amplification

Ten-year update of the international registry on cytokine-induced killer cells in cancer immunotherapy

Cytokine-induced killer (CIK) cells represent an exceptional T-cell population uniting a T cell and natural killer cell-like phenotype in their terminally differentiated CD3⁺ CD56⁺ subset, which features non-MHC-restricted tumor-killing activity. CIK cells have provided encouraging results in initial clinical studies and revealed synergistic antitumor effects when combined with standard therapeutic procedures. We established the international registry on CIK cells (IRCC) to collect and evaluate clinical trials for the treatment of cancer patients in 2010. Moreover, our registry set new standards on the reporting of results from clinical trials using CIK cells. In the present update, a total of 106 clinical trials including 10,225 patients were enrolled in IRCC, of which 4,889 patients in over 30 distinct tumor entities were treated with CIK cells alone or in combination with conventional or novel therapies. Significantly improved median progression-free survival and overall survival were shown in 27 trials, and 9 trials reported a significantly increased 5-year survival rate. Mild adverse effects and graft-versus-host diseases were also observed in the studies. Recently, more efforts have been put into the improvement of antitumoral efficacy by CIK cells including the administration of immune checkpoint inhibitors and modification with chimeric antigen receptorc. The minimal toxicity and multiple improvements on their tumor-killing activity both make CIK cells a favorable therapeutic tool in the clinical practice of cancer immunotherapy.

A novel simplified method of generating cytomegalovirus-specific cytokine-induced killer cells of high specificity and superior potency with GMP compliance

We describe a method of rendering polyclonal cytokine-induced killer cells (CIK) specific against cytomegalovirus (CMV), focusing on GMP compliance. Peripheral blood mononuclear cells (PBMNC) are stimulated with pooled CMV peptides pp65 and IE-1 for 16-24 h and the reactive T cell subset which up-regulate CD137 is further co-stimulated with anti-CD137, followed by expansion in G-Rex flasks under standard CIK culture condition. This method generates a large number CMV-specific CIK with superior potency compared to published method currently in clinical trials. The cytotoxicity as measured by chromium release assay correlates with the upregulation of CD107a upon peptide re-challenge as measured by flow cytometry. CMV-CIK at maturity consist of mainly late effector memory CD8 T cells and have a skewed TCR repertoire with preferential expansion of a few families. Such CMV-CIK retain their function after freezing and thawing. CMV-CIK thus generated is ready for clinical trial against drug-resistant CMV disease.

Improving Clinical Manufacturing of IL-15 Activated Cytokine-Induced Killer (CIK) Cells

Cytokine-induced killer (CIK) cells are an immunotherapeutic approach to combat relapse following allogeneic hematopoietic stem cell transplantation (HSCT) in acute leukemia or myelodysplastic syndrome (MDS) patients. Prompt and sequential administration of escalating cell doses improves the efficacy of CIK cell therapy without exacerbating graft vs. host disease (GVHD). This study addresses manufacturing-related issues and aimed to develop a time-, personal- and cost-saving good manufacturing process (GMP)-compliant protocol for the generation of ready-for-use therapeutic CIK cell doses starting from one unstimulated donor-derived peripheral blood (PB) or leukocytapheresis (LP) products. Culture medium with or without the addition of either AB serum, fresh frozen plasma (FFP) or platelet lysate (PL) was used for culture. Fresh and cryopreserved CIK cells were compared regarding expansion rate, viability, phenotype, and ability to inhibit leukemia growth. Cell numbers increased by a median factor of 10-fold in the presence of FFP, PL, or AB serum, whereas cultivation in FFP/PL-free or AB serum-free medium failed to promote adequate CIK cell proliferation (p < 0.01) needed to provide clinical doses of 1 × 10⁶ T cells/kG, 5 × 10⁶ T cells/kG, 1 × 10⁷ T cells/kG, and 1 × 10⁸ T cells/kG recipient body weight. CIK cells consisting of T cells, T- natural killer (T-NK) cells and a minor fraction of NK cells were not significantly modified by different medium supplements. Moreover, neither cytotoxic potential against leukemic THP-1 cells nor cell activation shown by CD25 expression were significantly influenced. Moreover, overnight and long-term cryopreservation had no significant effect on the composition of CIK cells, their phenotype or cytotoxic potential. A viability of almost 93% (range: 89–96) and 89.3% (range: 84–94) was obtained after freeze-thawing procedure and long-term storage, respectively, whereas viability was 96% (range: 90-97) in fresh CIK cells. Altogether, GMP-complaint CIK cell generation from an unstimulated donor-derived PB or LP products was feasible. Introducing FFP, which is easily accessible, into CIK cell cultures was time- and cost-saving without loss of viability and potency in a 10-12 day batch culture. The feasibility of cryopreservation enabled storage and delivery of sequential highly effective ready-for-use CIK cell doses and therefore reduced the number of manufacturing cycles.

Donor-Derived Cytokine-Induced Killer Cell Infusion as Consolidation after Nonmyeloablative Allogeneic Transplantation for Myeloid Neoplasms

Non-myeloablative conditioning, such as with total lymphoid irradiation and antithymocyte globulin (TLI-ATG), has allowed allogeneic hematopoietic cell transplantation (allo-HCT) with curative potential for older patients and those with comorbid medical conditions with myeloid neoplasms. However, early achievement of full donor chimerism (FDC) and relapse remain challenging. Cytokine-induced killer (CIK) cells have been shown to have antitumor cytotoxicity. Infusion of donor-derived CIK cells has been studied for hematologic malignancies relapsed after allo-HCT but has not been evaluated as post-transplant consolidation. In this phase II study, we prospectively studied whether a one-time infusion of 1 × 10⁸/kg CD3⁺ donor-derived CIK cells administered between day +21 and day +35 after TLI-ATG conditioning could improve achievement of FDC by day +90 and 2-year clinical outcomes in patients with myeloid neoplasms. CIK cells, containing predominantly CD3⁺CD8⁺NKG2D⁺ cells along with significantly expanded CD3⁺CD56⁺ cells, were infused in 31 of 44 patients. Study outcomes were compared to outcomes of a retrospective historical cohort of 100 patients. We found that this one-time CIK infusion did not increase the rate of FDC by day +90. On an intention-to-treat analysis, 2-year non-relapse mortality (6.8%; 95% confidence interval [CI], 0-14.5%), event-free survival (27.3%; 95% CI, 16.8-44.2%), and overall survival (50.6%; 95% CI, 37.5-68.2%) were similar to the values seen in the historical cohort. The cumulative incidence of grade II-IV acute graft-versus-host disease at 1-year was 25.1% (95% CI, 12-38.2%). On univariate analysis, the presence of monosomal or complex karyotype was adversely associated with relapse-free survival and overall survival. Given the favorable safety profile of CIK cell infusion, strategies such as repeat dosing or genetic modification merit exploration. This trial was registered at ClinicalTrials.gov (NCT01392989).

Clearance of Hematologic Malignancies by Allogeneic Cytokine-Induced Killer Cell or Donor Lymphocyte Infusions

Well-established donor lymphocyte infusion (DLI) and novel cytokine-induced killer (CIK) cell therapy for the treatment of relapsing hematologic malignancies after allogeneic hematopoietic stem cell transplantation (HSCT) were compared with respect to feasibility, safety, and efficacy. Altogether, a total of 221 infusions were given to 91 patients (DLI, n = 55; CIK, n = 36). T cell recovery was significantly improved after CIK cell therapy (P < .0001). Although patients with CIK cell treatment showed a significantly worse prognosis at the time of HSCT (risk score, 1.7 versus 2.1; P < .0001), DLI and CIK cell therapy induced complete remission (CR) in 29% and 53% patients, respectively, whereas relapse occurred in 71% and 47%. In both groups, all patients with overt hematologic relapse at the time of immunotherapy (DLI, n = 11; CIK, n = 8) succumbed to their disease, while 36% and 68% patients with DLI or CIK cell therapy applied due to molecular relapse or active disease at the time of transplantation achieved CR. The 6-month overall survival rate in the latter patients was 57% and 77%, respectively, with a median follow-up of 27.9 months (range, .9 to 149.2 months). The 6-month cumulative incidence of relapse was 55% and 22% in patients who received DLI and CIK cell therapy, respectively (P = .012). Acute graft-versus-host disease developed in 35% of the patients who received DLI and in 25% of those who received CIK. No transfusion-related deaths occurred. These data, while underscoring the therapeutic value of conventional DLI, suggest the improved safety and to a certain extent efficacy of CIK cell therapy for patients at high risk for post-transplantation relapse of various hematologic malignancies.

Cellular immunotherapy for acute myeloid leukemia: How specific should it be?

Significant improvements in the survival of patients with hematological cancers following hematopoietic stem cell transplantation provide evidence supporting the potency of immune cell-mediated anti-leukemic effects. Studies focusing on immune cell-based cancer therapies have made significant breakthroughs in the last few years. Adoptive cellular therapy (ACT), and chimeric antigen receptor (CAR) T cell therapy, in particular, has significantly increased the survival of patients with B cell acute lymphoblastic leukemia and aggressive B cell lymphoma. Despite antigen-negative relapses and severe toxicities such as cytokine release syndrome after treatment, CAR-T cell therapies have been approved by the FDA in some conditions. Although a number of studies have tried to achieve similar results for acute myeloid leukemia (AML), clinical outcomes have not been as promising. In this review, we summarize recent and ongoing studies on cellular therapies for AML patients, with a focus on antigen-specific versus -nonspecific approaches.

Cord blood-derived cytokine-induced killer cells combined with blinatumomab as a therapeutic strategy for CD19+ tumors

BACKGROUND

Cytokine-induced killer cells (CIKs) are an advanced therapeutic medicinal product (ATMP) that has shown therapeutic activity in clinical trials but needs optimization. We developed a novel strategy using CIKs from banked cryopreserved cord blood units (CBUs) combined with bispecific antibody (BsAb) blinatumomab to treat CD19⁺ malignancies.

METHODS

CB-CIKs were expanded in vitro and fully characterized in comparison with peripheral blood (PB)-derived CIKs.

RESULTS

CB-CIKs, like PB-CIKs, were mostly CD3⁺ T cells with mean 45% CD3⁺CD56⁺ and expressing mostly TCR(T cell receptor)αβ with a TH1 phenotype. CB-CIK cultures had, however, a larger proportion of CD4⁺ cells, mostly CD56^-, as well as a greater proportion of naïve CCR7⁺CD45RA⁺ and a lower percentage of effector memory cells, compared with PB-CIKs. CB-CIKs were very similar to PB-CIKs in their expression of a large panel of co-stimulatory and inhibitory/exhaustion markers, except for higher CD28 expression among CD8⁺ cells. Like PB-CIKs, CB-CIKs were highly cytotoxic in vitro against natural killer (NK) cell targets and efficiently lysed CD19⁺ tumor cells in the presence of blinatumomab, with 30-60% lysis of target cells at very low effector:target ratios. Finally, both CB-CIKs and PB-CIKs, combined with blinatumomab, showed significant therapeutic activity in an aggressive PDX Ph⁺ CD19⁺ acute lymphoblastic leukemia model in NOD-SCID mice, without sign of toxicity or graft-versus-host disease. The improved expansion protocol was finally validated in good manufacturing practice conditions, showing reproducible expansion of CIKs from cryopreserved cord blood units with a median of 28.8 × 10⁶ CIK/kg.

DISCUSSION

We conclude that CB-CIKs, combined with bispecific T-cell-engaging antibodies, offer a novel, effective treatment strategy for leukemia.

Cytokine-induced killer cells/dendritic cells-cytokine induced killer cells immunotherapy combined with chemotherapy for treatment of colorectal cancer in China: a meta-analysis of 29 trials involving 2,610 patients

Purpose

To systematically evaluate the efficacy and safety of Cytokine-induced killer cells/dendritic cells-cytokine induced killer cells (CIK/DC-CIK) immunotherapy in treating advanced colorectal cancer (CRC) patients.

Results

29 trials including 2,610 CRC patients were evolved. Compared with chemotherapy alone, the combination of chemotherapy with CIK/DC-CIK immunotherapy significantly prolonged the overall survival rate (OS) and disease-free survival rate (DFS) (1–5 year OS, P < 0.01; 1-, 2-, 3- and 5-year DFS, P < 0.01). The combined therapy also improved patients’ overall response, disease control rate and life quality (P < 0.05). After immunotherapy, lymphocyte subsets percentages of CD3⁺, CD3⁻CD56⁺, CD3⁺CD56⁺ and CD16⁺CD56⁺ (P < 0.01) and cytokines levels of IL-2 and IFN-γ (P < 0.05) were increased, while CD4⁺, CD8⁺ and CD4⁺CD25⁺ and IL-6 and TNF-α did not show significant change (P > 0.05).

Materials and Methods

Clinical trials reporting response or safety of CIK/DC-CIK immunotherapy treating advanced CRC patients and published before September 2016 were searched in Cochrane Library, EMBASE, PubMed, Wanfang and CNKI database. Research quality and heterogeneity were evaluated before analysis. Pooled analyses were performed using random or fixed-effect models.

Conclusions

The combination of CIK/DC-CIK immunotherapy and chemotherapy prolong CRC patients’ survival time, enhanced patients’ immune function and alleviates the adverse effects caused by chemotherapy.

Influence of different ex vivo cell culture methods on the proliferation and anti-tumor activity of cytokine-induced killer cells from gastric cancer patients

Purpose

In cytokine-induced killer (CIK) cell therapy, the phenotypes and the numbers of CIK cells have a great influence on the therapeutic effects. This study aimed to investigate the effects of different ex vivo cell culture methods on the proliferation and cytotoxicity of CIK cells that were obtained from gastric cancer patients.

Patients and methods

CIK precursor (Pre-CIK) cells were collected by either hydroxyethyl starch (HES) sedimentation (HES method, unpurified group) or Ficoll-Hypaque density gradient centrifugation (Ficoll method, purified group). Cell number, collection time, and morphology of Pre-CIK cells in the two groups were determined. The proliferation ability, cytokines, phenotypes, and cytotoxicity of CIK cells in the two groups were evaluated ex vivo and in vivo.

Results

In this study, the number of Pre-CIK cells in the unpurified group was significantly higher than that in the purified group (P<0.05). Numbers of erythrocytes, platelets, and granulocytes were reduced significantly following the purification step (P<0.05). Compared to CIK cells in the purified group, those in the unpurified group showed more active proliferation, accompanied by higher percentages of CD8⁺, CD3^-CD56⁺, and CD3⁺CD56⁺ cells, which were responsible for cytotoxicity of CIK cells (P<0.05). This research also showed that the levels of interferon-γ, interleukin-2, and tumor necrosis factor-α, which can enhance the proliferation and cytotoxicity of CIK cells, were significantly increased in the unpurified group (P<0.05). Furthermore, CIK cells in the unpurified group also showed stronger anti-tumor effects against gastric cancer cells than those in the purified group, both ex vivo and in vivo (P<0.05).

Conclusion

The removal of Ficoll-Hypaque purification step reduces the time and cost of the Pre-CIK separation and provides more CIK cells with higher cytotoxicity, which is of great importance in the clinical application of CIK cell therapy.

Chemotherapy plus dendritic cells co-cultured with cytokine-induced killer cells versus chemotherapy alone to treat advanced non-small-cell lung cancer: A meta-analysis

This study was aimed to investigate the efficacy and safety of the combination treatment of dendritic cells co-cultured with cytokine-induced killer cells and chemotherapy for patients with advanced non-small-cell lung cancer (NSCLC). Literatures were searched from the Cochrane Library Central, PubMed, Web of Science and EMBASE. The primary endpoint of interest was overall survival (OS), and secondary endpoints were disease control rate (DCR) and progression free survival (PFS). Finally 7 trials published between January 2005 and March 2016 met inclusion criteria and totally 610 patients were enrolled. The combination group showed advance in DCR (RR = 1.31, 95% CI = 1.13-1.52, p = 0.0004), 1-year OS (RR = 1.18, 95% CI = 1.05-1.33, p = 0.007), and 2-year OS (RR = 1.37, 95% CI = 1.10-1.70, p = 0.005), with statistical significance. The proportions of CD3⁺ T cells (p = 0.002), NK cells (p = 0.02) and NKT cells (p = 0.001) were significantly higher in the peripheral blood of combination group, compared with those of the control group. Moreover, adverse reactions were obviously decreased in the combination group. However, no significant difference was identified in ORR and PFS between two groups (p > 0.05). In conclusion, the combination therapy was safe and applicable for patients with advanced NSCLC.

Innovative Clinical Perspectives for CIK Cells in Cancer Patients

Cytokine-induced killer (CIK) cells are T lymphocytes that have acquired, in vitro, following extensive manipulation by Interferon gamma (IFN-γ), OKT3 and Interleukin 2 (IL-2) addition, the expression of several Natural Killer (NK) cell-surface markers. CIK cells have a dual "nature", due to the presence of functional TCR as well as NK molecules, even if the antitumoral activity can be traced back only to the NK-like structures (DNAM-1, NKG2D, NKp30 and CD56). In addition to antineoplastic activity in vitro and in several in-vivo models, CIK cells show very limited, if any, GvHD toxicity as well as a strong intratumoral homing. For all such reasons, CIK cells have been proposed and tested in many clinical trials in cancer patients both in autologous and allogeneic combinations, up to haploidentical mismatching. Indeed, genetic modification of CIK cells as well as the possibility of combining them with specific monoclonal antibodies will further expand the possibility of their clinical utilization.

Adjuvant immunotherapy of dendritic cells and cytokine-induced killer cells is safe and enhances chemotherapy efficacy for multiple myeloma in China: a meta-analysis of clinical trials

Objective

The aim of this study was to systematically evaluate the efficacy and safety of the combination of dendritic cells and cytokine-induced killer cells (DC–CIK) adjuvant immunotherapy and chemotherapy in the treatment of multiple myeloma (MM).

Methods

Clinical trials were gathered by searching Web of Science, PubMed, Embase, Cochrane Library, Wanfang, and CNKI database. Outcome measurements including therapeutic efficacy, prognosis, immune function, and adverse events were extracted and evaluated.

Results

A total of 12 trials including 594 MM patients were involved in this study for statistical analysis. Results indicated that compared to chemotherapy alone, the combination of DC–CIK immunotherapy with chemotherapy significantly improved patients’ overall response rate (ORR, odds ratio [OR] =2.77, 95% confidence interval [CI] =1.88–4.10, P<0.00001), disease control rate (DCR, OR =2.90, CI =1.72–4.90, P<0.0001), and life quality (P<0.00001). The combined therapy showed advantages over chemotherapy alone in prognostic indicators including percentage of tumor cells (P=0.04), serum levels of β2-microglobin (P<0.0001), M protein (P<0.00001), and creatinine (P<0.0001), and 24 h urine light chains (P<0.00001). After combined treatment, CD4⁺ lymphocyte subsets’ percentages, CD4⁺/CD8⁺ ratio, and cytokines levels of AgNOR, IFN-γ, IL-2, and IL-12 were significantly increased (P<0.05), whereas CD8⁺ and CD4⁺CD25⁺ percentages and IL-4, IL-6, IL-10, and TGF-β levels were obviously decreased (P<0.01), indicating a recovered immune condition.

Conclusion

Adjuvant DC–CIK immunotherapy enhances the efficacy of chemotherapy for MM and improves prognosis probably by reconstructing immune function.

Cellular Immunotherapy for Hematologic Malignancies: Beyond Bone Marrow Transplantation

Immunotherapy has changed treatment practices for many hematologic malignancies. Even in the current era of targeted therapy, chemotherapy remains the backbone of treatment for many hematologic malignancies, especially in acute leukemias, where relapse remains the major cause of mortality. Application of novel immunotherapies in hematology attempts to harness the killing power of the immune system against leukemia and lymphoma. Cellular immunotherapy is evolving rapidly for high-risk hematologic disorders. Recent advances include chimeric antigen-receptor T cells, mesenchymal stromal/stem cells, dendritic cell tumor vaccines, cytokine-induced killer cells, and virus-specific T cells. The advantages of nontransplantation cellular immunotherapy include suitability for patients for whom transplantation has failed or is contraindicated, and a potentially less-toxic treatment alternative to transplantation for relapsed/refractory patients. This review examines those emerging cellular immunotherapies that are changing treatment paradigms for patients with hematologic malignancies.

Anticancer cellular immunotherapies derived from umbilical cord blood

INTRODUCTION

The lack of highly effective drugs in many malignancies has prompted scientific interest in the development of alternative treatment strategies. Cellular immunotherapy involving the adoptive transfer of immune cells that potently recognize and eliminate malignantly transformed cells has become a promising new tool in the anticancer armory. Studies suggest that the unique biological properties of umbilical cord blood (UCB) cells could precipitate enhanced anticancer activity; hence, UCB could be an optimal source for immunotherapy with the potential to provide products with 'off-the-shelf' availability.

AREAS COVERED

In this review, the authors summarize data on the transfer of naturally occurring or genetically modified UCB cells to treat cancer. The focus within is on the phenotypic and functional differences compared to other sources, the alloreactive and anticancer properties, and manufacturing of these products. Therapies utilizing cytokine-induced killer (CIK) cells, natural killer (NK) cells and chimeric antigen receptor (CAR) T-cells, are discussed.

EXPERT OPINION

The cellular immunotherapy field has become a growing, exciting area that has generated much enthusiasm. There is evidence that anticancer immunotherapy with UCB-derived products is feasible and safe; however, considering the limited number of clinical trials using UCB-derived products, further studies are warranted to facilitate translation into clinical practice.

The progress and current status of immunotherapy in acute myeloid leukemia

Recently, there has been remarkable progress in basic and preclinical studies of acute myeloid leukemia (AML). The improved outcomes of AML can largely be attributed to advances in supportive care and hematopoietic cell transplantation as opposed to conventional chemotherapy. However, as the 5-year survival rate remains low due to a high incidence of relapse, novel and effective treatments are urgently needed. Increasing attention is focusing on identifying suitable immunotherapeutic strategies for AML. Here, we describe the immunological features, mechanisms of immune escape, and recent progress in immunotherapy for AML. Problems encountered in the clinic will also be discussed. Although current outcomes may be limited, ongoing preclinical or clinical efforts are aimed at improving immunotherapy modalities and designing novel therapies, such as vaccines, monoclonal antibody therapy, chimeric antibody receptor-engineered T cells (CAR-T), TCR-engineered T cells (TCR-T), and checkpoint inhibitors, which may provide promising and effective therapies with higher specificity and efficacy for AML.

Cytokine-Induced Killer Cells As Pharmacological Tools for Cancer Immunotherapy

Cytokine-induced killer (CIK) cells are a heterogeneous population of effector CD3⁺CD56⁺ natural killer T cells, which can be easily expanded in vitro from peripheral blood mononuclear cells. CIK cells work as pharmacological tools for cancer immunotherapy as they exhibit MHC-unrestricted, safe, and effective antitumor activity. Much effort has been made to improve CIK cells cytotoxicity and treatments of CIK cells combined with other antitumor therapies are applied. This review summarizes some strategies, including the combination of CIK with additional cytokines, dendritic cells, check point inhibitors, antibodies, chemotherapeutic agents, nanomedicines, and engineering CIK cells with a chimeric antigen receptor. Furthermore, we briefly sum up the clinical trials on CIK cells and compare the effect of clinical CIK therapy with other immunotherapies. Finally, further research is needed to clarify the pharmacological mechanism of CIK and provide evidence to formulate uniform culturing criteria for CIK expansion.

FOLFOX regimen plus dendritic cells-cytokine-induced killer cells immunotherapy for the treatment of colorectal cancer: a meta-analysis

Purpose

To systematically investigate the efficacy and safety of the combination of FOLFOX (oxaliplatin, 5-fluorouracil, and leucovorin) regimen and cocultured dendritic cells and cytokine-induced killer cells (DC-CIK) immunotherapy for the treatment of colorectal cancer (CRC).

Methods

Publications reporting the clinical trials’ responses or safety of FOLFOX regimen combined with DC-CIK immunotherapy in treating CRC patients were searched in PubMed, Embase, Cochrane Library, China National Knowledge Internet, and Wanfang databases. Trials meeting the selection criteria were analyzed. The overall survival (OS), overall response rate (ORR), disease control rate (DCR), tumor markers, immune function, and adverse events were evaluated.

Results

Ten trials including 881 CRC patients were analyzed in this meta-analysis. The combined therapy showed advantages over FOLFOX treatment-alone in 2-year OS (odds ratio [OR] =2.77, confidence interval [CI] =1.58–4.86, P=0.0004), ORR (OR =1.85, CI =1.34–2.56, P=0.0002), and DCR (OR =2.54, CI =1.76–3.67, P<0.00001), with statistical significance. After immunotherapy, lymphocyte subset percentages of CD3⁺ (P=0.0006) and CD4⁺ (P=0.01), CD4⁺/CD8⁺ ratio (P=0.0003), and levels of cytokines IFN-γ (P=0.003) and IL-2 (P=0.01) were significantly increased, whereas analysis of CD8⁺, CD3⁻CD56⁺, CD3⁺CD56⁺, CD4⁺CD25⁺, IL-6, and TNF-α did not show any significant difference (P>0.05). Moreover, the level of carcinoembryonic antigen was also decreased significantly upon immunotherapy (P<0.00001).

Conclusion

The combination of FOLFOX regimen and DC-CIK immunotherapy was safe and effective for CRC patients.

Cytotoxic potential of IL-15-activated cytokine-induced killer cells against human neuroblastoma cells

BACKGROUND

Neuroblastoma (NB) is the most common solid extracranial tumor in childhood. Despite advances in therapy, the prognosis is poor and optimized therapies are urgently needed. Therefore, we investigated the antitumor potential of interleukin-15 (IL-15)-activated cytokine-induced killer (CIK) cells against different NB cell lines.

PROCEDURE

CIK cells were generated from peripheral blood mononuclear cells by the stimulation with interferon-γ (IFN-γ), IL-2, OKT-3 and IL-15 over a period of 10-12 days. The cytotoxic activity against NB cells was analyzed by nonradioactive Europium release assay before and after blocking of different receptor-ligand interactions relevant in CIK cell-mediated cytotoxicity.

RESULTS

The final CIK cell products consisted in median of 83% (range: 75.9-91.9%) CD3⁺ CD56^- T cells, 14% (range: 5.2-20.7%) CD3⁺ CD56⁺ NK-like T cells and 2% (range: 0.9-4.8%) CD3^- CD56⁺ NK cells. CIK cells expanded significantly upon ex vivo stimulation with median rates of 22.3-fold for T cells, 58.3-fold for NK-like T cells and 2.5-fold for NK cells. Interestingly, CD25 surface expression increased from less than equal to 1% up to median 79.7%. Cytotoxic activity of CIK cells against NB cells was in median 34.7, 25.9 and 34.8% against the cell lines UKF-NB-3, UKF-NB-4 and SK-N-SH, respectively. In comparison with IL-2-stimulated NK cells, CIK cells showed a significantly higher cytotoxicity. Antibody-mediated blocking of the receptors NKG2D, TRAIL, FasL, DNAM-1, NKp30 and lymphocyte function-associated antigen-1 (LFA-1) significantly reduced lytic activity, indicating that diverse cytotoxic mechanisms might be involved in CIK cell-mediated NB killing.

CONCLUSIONS

Unlike the mechanism reported in other malignancies, NKG2D-mediated cytotoxicity does not constitute the major killing mechanism of CIK cells against NB.

Immunological and Translational Aspects of NK Cell-Based Antitumor Immunotherapies

Natural killer (NK) cells play a pivotal role in the first line of defense against cancer. NK cells that are deficient in CD3 and a clonal T cell receptor (TCR) can be subdivided into two major subtypes, CD56^dimCD16⁺ cytotoxic and CD56^brightCD16⁻ immunoregulatory NK cells. Cytotoxic NK cells not only directly kill tumor cells without previous stimulation by cytotoxic effector molecules, such as perforin and granzymes or via death receptor interactions, but also act as regulatory cells for the immune system by secreting cytokines and chemokines. The aim of this review is to highlight therapeutic strategies utilizing autologous and allogenic NK cells, combinations of NK cells with monoclonal antibodies to induce antibody-dependent cellular cytotoxicity, or immune checkpoint inhibitors. Additionally, we discuss the use of chimeric antigen receptor-engineered NK cells in cancer immunotherapy.

Strategies before, during, and after hematopoietic cell transplantation to improve T-cell immune reconstitution

T-cell immune reconstitution (IR) after allogeneic hematopoietic cell transplantation (allo-HCT) is highly variable between patients and may take several months to even years. Patients with delayed or unbalanced T-cell IR have a higher probability of developing transplantation-related morbidity, mortality, and relapse of disease. Hence, there is a need for strategies to better predict and improve IR to reduce these limitations of allo-HCT. In this review, we provide an update of current and in-near-future clinically relevant strategies before, during, and after transplantation to achieve successful T-cell IR. Potent strategies are choosing the right HCT source (eg, donor-recipient matching, cell dose, graft manipulation), individualized conditioning and serotherapy (eg, antithymocyte globulin), nutritional status, exercise, home care, modulation of microbiota, enhancing homeostatic peripheral expansion, promoting thymopoiesis, and the use of adjuvant-targeted cellular immunotherapies. Strategies to prevent graft-versus-host disease are important as well because this complication and the subsequent need for immunosuppression affects T-cell IR and function. These options aim for personalized precision transplantation, where allo-HCT therapy is designed to boost a well-balanced T-cell IR and limit complications in individual patients, resulting in overall lower morbidity and higher survival chances.

In-vitro influence of mycophenolate mofetil (MMF) and Ciclosporin A (CsA) on cytokine induced killer (CIK) cell immunotherapy

Background

Cytokine-induced-killer (CIK) cells are a promising immunotherapeutic approach for impending relapse following hematopoietic stem cell transplantation (HSCT). However, there is a high risk for treatment failure associated with severe graft versus host disease (GvHD) necessitating pharmaceutical intervention post-transplant. Whether immunosuppression with mycophenolate mofetil (MMF) or Ciclosporin A (CsA) influences the cytotoxic effect of CIK cell immunotherapy is still an open issue.

Methods

CIK cells were generated from PBMC as previously described followed by co-incubation with mycophenolic acid (MPA) or CsA. Proliferation, cytotoxicity and receptor expression were investigated following short- (24 h), intermediate- (3 days) and long-term (7 days) MPA incubation with the intention to simulate the in vivo situation when CIK cells were given to a patient with relevant MPA/CsA plasma levels.

Results

Short-term MPA treatment led to unchanged proliferation capacity and barely had any effect on viability and cytotoxic capability in vitro. The composition of CIK cells with respect to T-, NK-like T- and NK cells remained stable. Intermediate MPA treatment lacked effects on NKG2D, FasL and TRAIL receptor expression, while an influence on proliferation and viability was detectable. Furthermore, long-term treatment significantly impaired proliferation, restricted viability and drastically reduced migration-relevant receptors accompanied by an alteration in the CD4/CD8 ratio. CD3⁺CD56⁺ cells upregulated receptors relevant for CIK cell killing and migration, whereas T cells showed the most interference through significant reductions in receptor expression. Interestingly, CsA treatment had no significant influence on CIK cell viability and the cytotoxic potential against K562.

Conclusions

Our data indicate that if immunosuppressant therapy is indispensable, efficacy of CIK cells is maintained at least short-term, although more frequent dosing might be necessary.

Electronic supplementary material

The online version of this article (doi:10.1186/s12967-016-1024-4) contains supplementary material, which is available to authorized users.

Interleukin-15 enhances cytokine induced killer (CIK) cytotoxic potential against epithelial cancer cell lines via an innate pathway

CIK cells are a subset of effector lymphocytes endowed with a non-MHC restricted anti-tumor activity making them an appealing and promising cell population for adoptive immunotherapy. CIK are usually generated ex-vivo by initial priming with Interferon-γ (IFN-γ) and monoclonal antibody against CD3 (anti-CD3), followed by culture in medium containing Interleukin-2 (IL-2). Interleukin-15 (IL-15) shares with IL-2 similar biological functions and recently it has been reported to induce CIK with increased anti-leukemic potential. The aim of the study was to compare the killing efficacy of CIK generated by IL-2 alone or IL-2 and IL-15 toward tumor targets of different origins, leukemic cells and malignant cells from epithelial solid tumors. CIK bulk cultures were examined for cell proliferation, surface phenotype and cytotoxic potential against tumor cell lines K562, HL60, HeLa and MCF-7. The results showed that IL-15 is able to induce a selective expansion of CIK cells, but it is less effective in sustaining CIK cell proliferation compared to IL-2. Conversely, our data confirm and reinforce the feature of IL-15 to induce CIK cells with a potent cytotoxic activity mostly against tumor cells from epithelial solid malignancies via NKG2D-mediated mechanism.

A comparison between cytokine- and bead-stimulated polyclonal T cells: the superiority of each and their possible complementary role

Cytokine-induced killer (CIK) cells and T cells expanded by co-stimulation with beads presenting anti-CD3 and -CD28 antibodies are both polyclonal T cells under intensive laboratory and clinical studies, but there has not been any direct comparison between both. We compared the expansion, memory T cell subsets and cytotoxicity for T cells expanded in parallel by the two methods. Bead-stimulated T cells showed superior expansion as compared to CIK cells on D14 of culture. Bead-stimulated T cells consisted of a significantly higher CD4(+) subset and significantly lower CD8(+) subset as compared to CIK cells, as well as a higher proportion of less terminally differentiated T cells and a higher proportion of homing molecules. On the other hand, CIK cells exhibited significantly superior cytotoxicity against two myelomonocytic leukemia cell lines (THP-1 and U937) and two RCC cell lines (786.0 and CaKi-2). The cytotoxicity on D14 against THP-1 was 58.1 % for CIK cells and 8.3 % for bead-stimulated T cells at E:T of 10:1 (p < 0.01). Cytotoxicity correlated positively with the proportion of the CD8 subset in the culture and was independent of NKG2D recognition of susceptible targets. Polyclonal T cells expanded by different methods exhibit different characteristics which may define the specific role of each in different clinical scenario. We postulate that the more potent CIK cells may offer short term benefit while bead-stimulated T cells may offer a more sustained immune response.

Effectiveness and safety of chemotherapy combined with cytokine-induced killer cell /dendritic cell-cytokine-induced killer cell therapy for treatment of gastric cancer in China: A systematic review and meta-analysis

BACKGROUND

Currently, cytokine-induced killer cells (CIK)/dendritic cell (DC)-CIK-mediated immunotherapy is widely used to treat gastric cancer. However, limited information regarding clinical trials on CIK/DC-CIK therapy is available. Therefore, systemic evaluation of the efficacy and safety of the combination therapy is necessary.

METHODS

A meta-analysis involving 1735 patients with gastric cancer was conducted. Before analysis, the study quality and heterogeneity were evaluated. The effects of chemotherapy combined with CIK/DC-CIK on gastric cancer were compared with the effects observed when chemotherapy alone was used. Pooled analysis was performed using RevMan version 5.2 from random or fixed-effect models.

RESULTS

Seventeen trials were included. First, the analysis showed that the combination therapy significantly increased the overall survival rate and disease-free survival rate compared with those in patients treated using chemotherapy alone. The overall response rate (P = 0.002), disease control rate (P = 0.0007), and quality of life improved rate (P = 0.0008) were significantly improved in patients who received combined treatment than in patients who received chemotherapy alone. Second, the percentage of lymphocyte subsets (CD3(+), CD4(+) and CD3(-)CD56(+), CD3(+)CD56(+); P <0.01) and the levels of interleukin-12 and interferon-γ, which reflect immune function, were significantly increased (P <0.05) after the CIK/DC-CIK therapy. Further, carbohydrate antigen tumor markers were significantly reduced compared with the pre-therapy levels. Immunotherapy with CIK/DC-CIK obviously alleviated the adverse events caused by chemotherapy.

CONCLUSION

The combination of CIK/DC-CIK therapy and chemotherapy was superior in prolonging the survival time, enhancing immune function and alleviating the adverse events caused by chemotherapy.

Immunotherapy of DC-CIK cells enhances the efficacy of chemotherapy for solid cancer: a meta-analysis of randomized controlled trials in Chinese patients

OBJECTIVE

Professional antigen-presenting dendritic cells (DCs) and cytokine-induced killer (CIK) cells, components of anti-cancer therapy, have shown clinical benefits and potential to overcome chemotherapeutic resistance. To evaluate whether DC-CIK cell-based therapy improves the clinical efficacy of chemotherapy, we reviewed the literature on DC-CIK cells and meta-analyzed randomized controlled trials (RCTs).

METHODS

We searched several databases and selected studies using predefined criteria. RCTs that applied chemotherapy with and without DC-CIK cells separately in two groups were included. Odds ratio (OR) and mean difference (MD) were reported to measure the pooled effect.

RESULTS

Twelve reported RCTs (826 patients), which were all performed on Chinese patients, were included. Combination therapy exhibited better data than chemotherapy: 1-year overall survival (OS) (OR=0.22, P<0.01), 2-year OS (OR=0.28, P<0.01), 3-year OS (OR=0.41, P<0.01), 1-year disease-free survival (DFS) (OR=0.16, P<0.05), 3-year DFS (OR=0.32, P<0.01), objective response rate (ORR) (OR=0.54, P<0.01), and disease control rate (DCR) (OR=0.46, P<0.01). Moreover, the levels of CD3(+) T-lymphocytes (MD=-11.65, P<0.05) and CD4(+) T-lymphocytes (MD=-8.18, P<0.01) of the combination group were higher.

CONCLUSIONS

Immunotherapy of DC-CIK cells may enhance the efficacy of chemotherapy on solid cancer and induces no specific side effect. Further RCTs with no publishing bias should be designed to confirm the immunotherapeutic effects of DC-CIK cells.

UV-inactivated HSV-1 potently activates NK cell killing of leukemic cells

Herein we demonstrate that oncolytic herpes simplex virus-1 (HSV-1) potently activates human peripheral blood mononuclear cells (PBMCs) to lyse leukemic cell lines and primary acute myeloid leukemia samples, but not healthy allogeneic lymphocytes. Intriguingly, we found that UV light-inactivated HSV-1 (UV-HSV-1) is equally effective in promoting PBMC cytolysis of leukemic cells and is 1000- to 10 000-fold more potent at stimulating innate antileukemic responses than UV-inactivated cytomegalovirus, vesicular stomatitis virus, reovirus, or adenovirus. Mechanistically, UV-HSV-1 stimulates PBMC cytolysis of leukemic cells, partly via Toll-like receptor-2/protein kinase C/nuclear factor-κB signaling, and potently stimulates expression of CD69, degranulation, migration, and cytokine production in natural killer (NK) cells, suggesting that surface components of UV-HSV-1 directly activate NK cells. Importantly, UV-HSV-1 synergizes with interleukin-15 (IL-15) and IL-2 in inducing activation and cytolytic activity of NK cells. Additionally, UV-HSV-1 stimulates glycolysis and fatty acid oxidation-dependent oxygen consumption in NK cells, but only glycolysis is required for their enhanced antileukemic activity. Last, we demonstrate that T cell-depleted human PBMCs exposed to UV-HSV-1 provide a survival benefit in a murine xenograft model of human acute myeloid leukemia (AML). Taken together, our results support the preclinical development of UV-HSV-1 as an adjuvant, alone or in combination with IL-15, for allogeneic donor mononuclear cell infusions to treat AML.

Immune checkpoint inhibitors enhance cytotoxicity of cytokine-induced killer cells against human myeloid leukaemic blasts

We studied whether blockade of inhibitory receptors on cytokine-induced killer (CIK) cells by immune checkpoint inhibitors could increase its anti-tumour potency against haematological malignancies. CIK cultures were generated from seven normal donors and nine patients with acute myeloid leukaemia (AML), acute lymphoblastic leukaemia (ALL) or multiple myeloma (MM). The inhibitory receptors B and T lymphocyte attenuator, CD200 receptor, lymphocyte activation gene-3 (LAG-3) and T cell immunoglobulin and mucin-domain-containing-3 (TIM-3) were present at variable percentages in most CIK cultures, while cytotoxic T lymphocyte-associated protein 4 (CTLA-4), programmed death-1 (PD-1) and killer cell immunoglobulin-like receptors (KIR2DL1/2/3) were expressed at low level in most cultures. Without blockade, myeloid leukaemia cells were susceptible to autologous and allogeneic CIK-mediated cytotoxicity. Blockade of KIR, LAG-3, PD-1 and TIM-3 but not CTLA-4 resulted in remarkable increase in killing against these targets, even in those with poor baseline cytotoxicity. ALL and MM targets were resistant to CIK-mediated cytotoxicity, and blockade of receptors did not increase cytotoxicity to a meaningful extent. Combination of inhibitors against two receptors did not further increase cytotoxicity. Interestingly, potentiation of CIK killing by blocking antibodies was not predicted by expression of receptors on CIK and their respective ligands on the targets. Compared to un-activated T and NK cells, blockade potentiated the cytotoxicity of CIK cells to a greater degree and at a lower E:T ratio, but without significant increase in cytotoxicity against normal white cell. Our findings provide the basis for clinical trial combining autologous CIK cells with checkpoint inhibitors for patients with AML.

NK Cell-Mediated Antibody-Dependent Cellular Cytotoxicity in Cancer Immunotherapy

Natural killer (NK) cells play a major role in cancer immunotherapies that involve tumor-antigen targeting by monoclonal antibodies (mAbs). NK cells express a variety of activating and inhibitory receptors that serve to regulate the function and activity of the cells. In the context of targeting cells, NK cells can be "specifically activated" through certain Fc receptors that are expressed on their cell surface. NK cells can express FcγRIIIA and/or FcγRIIC, which can bind to the Fc portion of immunoglobulins, transmitting activating signals within NK cells. Once activated through Fc receptors by antibodies bound to target cells, NK cells are able to lyse target cells without priming, and secrete cytokines like interferon gamma to recruit adaptive immune cells. This antibody-dependent cell-mediated cytotoxicity (ADCC) of tumor cells is utilized in the treatment of various cancers overexpressing unique antigens, such as neuroblastoma, breast cancer, B cell lymphoma, and others. NK cells also express a family of receptors called killer immunoglobulin-like receptors (KIRs), which regulate the function and response of NK cells toward target cells through their interaction with their cognate ligands that are expressed on tumor cells. Genetic polymorphisms in KIR and KIR-ligands, as well as FcγRs may influence NK cell responsiveness in conjunction with mAb immunotherapies. This review focuses on current therapeutic mAbs, different strategies to augment the anti-tumor efficacy of ADCC, and genotypic factors that may influence patient responses to antibody-dependent immunotherapies.

Adoptive Immunotherapies After Allogeneic Hematopoietic Stem Cell Transplantation in Patients With Hematologic Malignancies

Hematopoietic stem cell transplantation (HSCT) is the only curative therapy for patients with chemotherapy-resistant hematologic malignancies that are usually fatal in absence of treatment. Hematopoietic stem cell transplantation is associated with significant early and late morbidity and mortality. Graft-versus-host disease, infections, and relapse are the most important causes of mortality after HSCT. Until now, these complications have been managed mainly with pharmacological drugs, but in some situations, this approach clearly shows its limit. As such, there is a significant need for novel therapies for the treatment of complications after allogeneic HSCT. In this review, the currently available adoptive immunotherapies offering an alternative in case of treatment failure of HSCT complications will be described. The results of the main clinical trials based on immune cell infusion will be discussed and the strategies aiming at maximizing cytotoxic T-lymphocyte, regulatory T-cell, natural killer cell, cytokine-induced killer cell, and γδ T-cell efficacies in the context of immunotherapy approaches after allogeneic HSCT in patients with hematologic malignancies will be gathered.

Revving up Natural Killer Cells and Cytokine-Induced Killer Cells Against Hematological Malignancies

Natural killer (NK) cells belong to innate immunity and exhibit cytolytic activity against infectious pathogens and tumor cells. NK-cell function is finely tuned by receptors that transduce inhibitory or activating signals, such as killer immunoglobulin-like receptors, NK Group 2 member D (NKG2D), NKG2A/CD94, NKp46, and others, and recognize both foreign and self-antigens expressed by NK-susceptible targets. Recent insights into NK-cell developmental intermediates have translated into a more accurate definition of culture conditions for the in vitro generation and propagation of human NK cells. In this respect, interleukin (IL)-15 and IL-21 are instrumental in driving NK-cell differentiation and maturation, and hold great promise for the design of optimal NK-cell culture protocols. Cytokine-induced killer (CIK) cells possess phenotypic and functional hallmarks of both T cells and NK cells. Similar to T cells, they express CD3 and are expandable in culture, while not requiring functional priming for in vivo activity, like NK cells. CIK cells may offer some advantages over other cell therapy products, including ease of in vitro propagation and no need for exogenous administration of IL-2 for in vivo priming. NK cells and CIK cells can be expanded using a variety of clinical-grade approaches, before their infusion into patients with cancer. Herein, we discuss GMP-compliant strategies to isolate and expand human NK and CIK cells for immunotherapy purposes, focusing on clinical trials of adoptive transfer to patients with hematological malignancies.

HLA-E polymorphism and clinical outcome after allogeneic hematopoietic stem cell transplantation in Egyptian patients

Human leukocyte antigen-E (HLA)-E in a non-classical major histocompatibility complex (MHC) class I (Ib) molecule. HLA-E-peptide complex acts as a ligand for natural killer (NK) cells and CD8+ T lymphocytes playing a dual role in natural and acquired immune responses. The difference in expression levels between HLA-E alleles was suggested to have impact on transplantation outcome. The aim of the study is to evaluate the clinical effect of HLA-E alleles on transplantation in a group of Egyptian patients. HLA-E genotyping was analyzed in eighty-eight recipients of stem cell transplantation using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). HLA-E*01:03 allele showed a trend towards lower cumulative incidence of relapse at 2 years compared to homozygous HLA-E*01:01 genotype (8% versus 21.5%, p=0.09, HR: 0.30, 95% CI: 0.91-1.69). HLA-E was the only factor showing near significant association with relapse incidence. HLA-E polymorphism did not affect the cumulative incidence of acute GVHD grades II-IV at 100 days, the 2-year cumulative incidence of extensive chronic GVHD, transplant related mortality (TRM) or overall survival (OS).

CONCLUSION

the suggested association of HLA-E polymorphism with reduced risk of relapse needs verification in a larger cohort. However, its proposed role in GVL helps better understanding of alloreactivity of T cells and NK cells and their implication in immunotherapy post allogeneic hematopoietic stem cell transplantation.

Cytokine-induced killer cells: A novel immunotherapy strategy for leukemia

Cytokine-induced killer (CIK) cells are NK-like T cells derived from peripheral blood mononuclear cells that are co-stimulated and expanded using cytokines for 14–21 days in vitro. CIK cells are a heterogeneous subset of highly-efficient cytotoxic T effector cells that mediate major histocompatibility complex-unrestricted cytotoxicity against a broad array of tumor cells. These effector cells are generated from patients with leukemia or healthy donors who demonstrate similar cytotoxic activity against leukemia blasts. Allogeneic CIK cells retain the ability to produce the graft versus tumor response and generate minimal graft versus host disease. In addition, CIK cells possess no cytotoxicity against normal hematopoietic stem cells in vivo. Leukemia recurrence remains a formidable obstacle, but adoptive immunotherapy offers promise for the eradication of minimal residual disease and prevention of leukemia relapse following hematopoietic stem cell transplantation. CIK cell infusion started a novel generation of adoptive immunotherapy and exhibits particular potential applications in the area of hematological malignancy. In the present study, the previous strategies of leukemia immunotherapy using CIK cells are reviewed and the future directions of development are discussed.

Cytokine-induced killer (CIK) cells in cancer immunotherapy: report of the international registry on CIK cells (IRCC)

PURPOSE

Cytokine-induced killer (CIK) cells represent an exceptional T cell population uniting a T cell and natural killer cell like phenotype in their terminally differentiated CD3(+)CD56(+) subset, which features non-MHC-restricted tumor-killing activity. CIK cells are expandable from peripheral blood mononuclear cells and mature following the addition of certain cytokines. CIK cells have provided encouraging results in initial clinical studies and revealed synergistic antitumor effects when combined with standard therapeutic procedures.

METHODS

Therefore, we established the international registry on CIK cells in order to collect and evaluate data about clinical trials using CIK cells for the treatment of cancer patients. Moreover, our registry is expected to set new standards on the reporting of results from clinical trials using CIK cells. Clinical responses, overall survival (OS), adverse reactions and immunologic effects were analyzed in 45 studies present in our database. These studies investigated 22 different tumor entities altogether enrolling 2,729 patients.

RESULTS

A mean response rate of 39 % and significantly increased OS, accompanied by an improved quality of life, were reported. Interestingly, side effects of CIK cell treatment were minor. Mild fevers, chills, headache and fatigue were, however, seen regularly after CIK cell infusion. Moreover, CIK cells revealed numerous immunologic effects such as changes in T cell subsets, tumor markers, cytokine secretion and HBV viral load.

CONCLUSION

Due to their easy availability and potent antitumor activity, CIK cells emerged as a promising immunotherapy approach in oncology and may gain major importance on the prognosis of cancer.

Treatment of CD33-directed chimeric antigen receptor-modified T cells in one patient with relapsed and refractory acute myeloid leukemia

We conducted a clinical trial to assess the feasibility and efficacy of CD33-directed chimeric antigen receptor-modified T cells (CART-33) for the treatment of refractory acute myeloid leukemia (AML). A 41-year-old male patient with AML was enrolled and received a total of 1.12 × 10(9) autologous CART-33 cells, of which ~38% were transduced with CAR. The CART-33 infusion alone induced rigorous chills and fevers; drastic fluctuations of his preexisting pancytopenia; elevated serum cytokine levels, including interleukin (IL)-6, IL-8, tumor necrosis factor-α, and interferon-γ; slight transient hyperbilirubinemia within 2 weeks; a subsequent intermittent moderate fever; and reversed fluctuation of the pancytopenia. A marked decrease of blasts in the bone marrow was observed on examination 2 weeks after therapy, and there was a gradual increase until florid disease progression occurred at 9 weeks after the cell infusion. These observations warrant further research on CART-33 treatment in refractory AML and may spur efforts to extend the CART-33-induced tumor burden to the preparation of other intensive strategies, such as hematopoietic stem cell transplantation. This study is registered at www.ClinicalTrials.gov as NCT01864902.

Adoptive immunotherapy strategies with cytokine-induced killer (CIK) cells in the treatment of hematological malignancies

Cytokine-induced killer (CIK) cells are a heterogeneous population of immune effector cells that feature a mixed T- and Natural killer (NK) cell-like phenotype in their terminally-differentiated CD3+CD56+ subset. The easy availability, high proliferation rate and widely major histocompatibility complex (MHC)-unrestricted antitumor activity of CIK cells contribute to their particularly advantageous profile, making them an attractive approach for adoptive immunotherapy. CIK cells have shown considerable cytotoxicity against both solid tumors and hematological malignancies in vitro and in animal studies. Recently, initial clinical experiences demonstrated the feasibility and efficacy of CIK cell immunotherapy in cancer patients, even at advanced disease stages. Likewise, the clinical application of CIK cells in combination with standard therapeutic procedures revealed synergistic antitumor effects. In this report, we will focus our consideration on CIK cells in the treatment of hematological malignancies. We will give insight into the latest advances and future perspectives and outline the most prominent results obtained in 17 clinical studies. Overall, CIK cells demonstrated a crucial impact on the treatment of patients with hematological malignancies, as evidenced by complete remissions, prolonged survival durations and improved quality of life. However, up to now, the optimal application schedule eventually favoring their integration into clinical practice has still to be developed.

Will post-transplantation cell therapies for pediatric patients become standard of care?

Although allogeneic hematopoietic stem cell transplantation (HSCT) is a curative approach for many pediatric patients with hematologic malignancies and some nonmalignant disorders, some critical obstacles remain to be overcome, including relapse, engraftment failure, graft-versus-host disease (GVHD), and infection. Harnessing the immune system to induce a graft-versus-tumor effect or rapidly restore antiviral immunity through the use of donor lymphocyte infusion (DLI) has been remarkably successful in some settings. Unfortunately, however, the responses to DLI can be variable, and GVHD is common. Thus, manipulations to minimize GVHD while restoring antiviral immunity and enhancing the graft-versus-tumor effect are needed to improve outcomes after allogeneic HSCT. Cellular therapies, defined as treatment modalities in which hematopoietic or nonhematopoietic cells are used as therapeutic agents, offer this promise for improving outcomes post-HSCT. This review presents an overview of the field for pediatric cell therapies in the transplant setting and discusses how we can broaden applicability beyond phase I.