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.

Acknowledging tissue donation: Human cadaveric specimens in musculoskeletal research.

Human cadaveric specimens are an important resource for research, particularly in biomechanical studies, but their use also raises ethical questions and cannot simply be taken for granted. It was asked how much information authors publishing musculoskeletal research actually give about such specimens and about how they were acquired. The aim was to formulate recommendations on how this reporting might be improved. Relevant articles published between 2009 and 2012 in four North American or European journals were scanned for information regarding the characteristics of the human specimens used, their institutional source and the ethical or legal context of their acquisition. While the majority of articles report biological characteristics of specimens (sex, age at death, preservation method), only 40% of articles refer to body donation, only 23% report the institution that provided specimens, and only 17% refer to some kind of formalized approval of their research. There were regional and journal-to-journal differences. No standard for reporting studies involving human specimens could be detected. It is suggested that such a standard be developed by researchers and editors. Information on the source of specimens and on the ethical or legal basis should be regularly reported to acknowledge this unique research resource and to preserve the good relationship between researchers and the communities, that provide the required specimens by body donation and upon which researchers depend.

Immune profiling and functional analysis of NK and T cells in ataxia telangiectasia.

Ataxia telangiectasia (AT) is a rare autosomal-recessive disorder characterized by profound neurodegeneration, combined immunodeficiency, and an increased risk for malignant diseases. Treatment options for AT are limited, and the long-term survival prognosis for patients remains grim, primarily due to the emergence of chronic respiratory pathologies, malignancies, and neurological complications. Understanding the dysregulation of the immune system in AT is fundamental for the development of novel treatment strategies. In this context, we performed a retrospective longitudinal immunemonitoring of lymphocyte subset distribution in a cohort of AT patients (n = 65). Furthermore, we performed FACS analyses of peripheral blood mononuclear cells from a subgroup of 12 AT patients to examine NK and T cells for the expression of activating and functional markers. We observed reduced levels of peripheral blood CD3+CD8+ cytotoxic T cells, CD3+CD4+ T helper cells, and CD19+ B cells, whereas the amount of CD3--CD56+ NK cells and CD3+CD56+ NKT-like cells was similar compared with age-matched controls. Notably, there was no association between the age-dependent kinetic of T-, B-, or NK-cell counts and the occurrence of malignancy in AT patients. Additionally, our results indicate an altered NK- and T-cell response to cytokine stimulation in AT with increased levels of TRAIL, FasL, and CD16 expression in NK cells, as well as an elevated activation level of T cells in AT with notably higher expression levels of IFN-γ, CD107a, TRAIL, and FasL. Together, these findings imply function alterations in AT lymphocytes, specifically in T and NK cells, shedding light on potential pathways for innovative therapies.

Adoptive cellular immunotherapy for refractory childhood cancers: a single center experience.

Prognosis of refractory childhood cancers despite multimodal treatment strategies remains poor. Here, we report a single center experience encountered in 18 patients with refractory solid malignancies treated with adoptive cellular immunotherapy (ACI) from haploidentical or matched donors following hematopoietic stem cell transplantation. While seven patients were in partial and six in complete remission (CR), five patients suffered from relapsed diseases at the time of ACI. 1.5-year probabilities of overall survival (OS) and progression-free survival (PFS) were 19.5% and 16.1% for all patients. Patients in CR showed estimated 1.5-year OS and PFS of 50.1% and 42.7%, respectively. CR was induced or rather sustained in ten children, with two still being alive 9.6 and 9.3 years after ACI. Naïve, central and effector memory T-cells correlated with responses. However, the majority of patients relapsed. Cumulative incidence of relapse was 79.8% at 1.5 years. Acute graft versus host disease (aGVHD) occurred in nine of 18 patients (50%) with aGVHD grade I-II observed in six (33%) and aGVHD grade III seen in three (17%) patients, manageable in all cases. Altogether, study results indicate that donor-derived ACI at its current state offers palliation but no clear curative benefit for refractory childhood cancers and warrants further improvement.

The Synergistic Use of IL-15 and IL-21 for the Generation of NK Cells From CD3/CD19-Depleted Grafts Improves Their ex vivo Expansion and Cytotoxic Potential Against Neuroblastoma: Perspective for Optimized Immunotherapy Post Haploidentical Stem Cell Transplantation.

Neuroblastoma (NB) is the most common solid extracranial tumor in childhood. Despite therapeutic progress, prognosis in high-risk NB is poor and innovative therapies are urgently needed. Therefore, we addressed the potential cytotoxic capacity of interleukin (IL)-activated natural killer (NK) cells compared to cytokine-induced killer (CIK) cells for the treatment of NB. NK cells were isolated from peripheral blood mononuclear cells (PBMCs) by indirect CD56-enrichment or CD3/CD19-depletion and expanded with different cytokine combinations, such as IL-2, IL-15, and/or IL-21 under feeder-cell free conditions. CIK cells were generated from PBMCs by ex vivo stimulation with interferon-γ, IL-2, OKT-3, and IL-15. Comparative analysis of expansion rate, purity, phenotype and cytotoxicity was performed. CD56-enriched NK cells showed a median expansion rate of 4.3-fold with up to 99% NK cell content. The cell product after CD3/CD19-depletion consisted of a median 43.5% NK cells that expanded significantly faster reaching also 99% of NK cell purity. After 10-12 days of expansion, both NK cell preparations showed a significantly higher median cytotoxic capacity against NB cells relative to CIK cells. Remarkably, these NK cells were also capable of efficiently killing NB spheroidal 3D culture in long-term cytotoxicity assays. Further optimization using a novel NK cell culture medium and a prolonged culturing procedure after CD3/CD19-depletion for up to 15 days enhanced the expansion rate up to 24.4-fold by maintaining the cytotoxic potential. Addition of an IL-21 boost prior to harvesting significantly increased the cytotoxicity. The final cell product consisted for the major part of CD16-, NCR-expressing, poly-functional NK cells with regard to cytokine production, CD107a degranulation and antitumor capacity. In summary, our study revealed that NK cells have a significantly higher cytotoxic potential to combat NB than CIK cell products, especially following the synergistic use of IL-15 and IL-21 for NK cell activation. Therefore, the use of IL-15+IL-21 expanded NK cells generated from CD3/CD19-depleted apheresis products seems to be highly promising as an immunotherapy in combination with haploidentical stem cell transplantation (SCT) for high-risk NB patients.

Advanced flowcytometric analysis of regulatory T cells: CD127 downregulation early post stem cell transplantation and altered Treg/CD3(+)CD4(+)-ratio in severe GvHD or relapse.

Regulatory T cells (Tregs) are of crucial importance to suppress graft versus host disease (GvHD) post allogeneic stem cell transplantation (SCT), but are also known to impair antitumor immunity. However, Treg longitudinal studies are rare and in this respect advanced flowcytometric approaches for Treg characterization are necessary. To investigate the relation of both the percentage and the absolute numbers of Tregs on GvHD or relapse we measured CD4(+)CD25(+/hi)CD127(lo/-) Tregs in 239 peripheral blood (PB) samples of 16 patients during the first two years post-SCT. A 10-color flowcytometric panel was established to evaluate Treg subpopulations and has been tested in ten healthy individuals. In patients we demonstrated a decrease in CD127 expression on T cells early post-SCT which increases during the first year. Moreover, Tregs reached higher absolute numbers in patients with GvHD≤grade I compared to those with GvHD grades II-IV. In contrast, the percentage of Tregs was significantly higher in patients with GvHD grades II-IV or disease relapse compared to those without GvHD. These patients fit into the range of healthy individuals where a median value of 7.5% and 6.4% of T helper cells were characterized as CD4(+)CD25(+/hi)CD127(lo/-) and CD4(+)CD25(+/hi) Tregs, respectively. Furthermore, Tregs could be further subdivided into 40% naïve, 51% central memory and 9% effector memory Tregs. Our results showed for the first time a downregulation of CD127 expression on T cells including Tregs in patients early post-SCT. Additionally, new insights into the recovery of Tregs regarding GvHD and relapse were provided.