Identification of a New Subset of Myeloid Suppressor Cells in Peripheral Blood of Melanoma Patients With Modulation by a Granulocyte-Macrophage Colony-Stimulation Factor–Based Antitumor Vaccine

2007 ◽  
Vol 25 (18) ◽  
pp. 2546-2553 ◽  
Author(s):  
Paola Filipazzi ◽  
Roberta Valenti ◽  
Veronica Huber ◽  
Lorenzo Pilla ◽  
Paola Canese ◽  
...  

Purpose Phenotypic and functional features of myeloid suppressor cells (MSC), which are known to serve as critical regulators of antitumor T-cell responses in tumor-bearing mice, are still poorly defined in human cancers. Here, we analyzed myeloid subsets with suppressive activity present in peripheral blood of metastatic melanoma patients and evaluated their modulation by a granulocyte-macrophage colony-stimulating factor (GM-CSF) –based antitumor vaccine. Patients and Methods Stage IV metastatic melanoma patients (n = 16) vaccinated with autologous tumor-derived heat shock protein peptide complex gp96 (HSPPC-96) and low-dose GM-CSF provided pre- and post-treatment whole blood specimens. Peripheral-blood mononuclear cells (PBMCs) were analyzed by flow cytometry, separated into cellular subsets, and used for in vitro proliferation assays. PBMCs from stage-matched metastatic melanoma patients (n = 12) treated with non–GM-CSF-based vaccines (ie, HSPPC-96 alone or interferon alfa/melanoma–derived peptides) or sex- and age-matched healthy donors (n = 16) were also analyzed for comparison. Results The lack of or low HLA-DR expression was found to identify a CD14+ cell subset highly suppressive of lymphocyte functions. CD14+HLA-DR–/lo cells were significantly expanded in all metastatic melanoma patients, whereas they were undetectable in healthy donors. Suppressive activity was mediated by transforming growth factor beta (TGF-β), whereas no involvement of the arginase and inducible nitric oxide synthase pathways could be detected. CD14+HLA-DR–/lo cells, as well as spontaneous ex vivo release and plasma levels of TGF-β, were augmented after administration of the HSPPC-96/GM-CSF vaccine. No enhancement of the CD14+-mediated suppressive activity was found in patients receiving non–GM-CSF-based vaccines. Conclusion CD14+HLA-DR–/lo cells exerting TGF-β–mediated immune suppression represent a new subset of MSC potentially expandable by the administration of GM-CSF–based vaccines in metastatic melanoma patients.

2007 ◽  
Vol 25 (18_suppl) ◽  
pp. 21082-21082
Author(s):  
P. Filipazzi ◽  
R. Valenti ◽  
V. Huber ◽  
M. Iero ◽  
L. Pilla ◽  
...  

21082 Background: Phenotypic and functional features of myeloid suppressor cells (MSC), known to serve as critical regulators of anti-tumor T cell responses in tumor-bearing mice, are still poorly defined in human cancers. Here we analyzed myeloid subsets with suppressive activity present in peripheral blood of metastatic melanoma patients (MM) and evaluated their modulation by a GM-CSF-based anti- tumor vaccine. Methods: Stage IV AJCC MM patients (n=16) vaccinated with autologous tumor-derived heat-shock protein peptide complexes gp96 (HSPPC-96) and low dose GM-CSF provided pre- and post-treatment whole blood samples. Peripheral blood mononuclear cells (PBMC) were analyzed by flow cytometry, separated into cellular subsets and used for in vitro proliferation assays. PBMC from stage- matched melanoma patients (n=12) treated with non-GM-CSF-based vaccines (i.e. HSPPC-96 alone or IFNa/melanoma-derived peptides) or gender and age-matched healthy donors (n=16) were also analyzed for comparison. Results: The lack or low levels of HLA-DR expression was found to identify a CD14+ cell subset with high suppressive activity on lymphocyte proliferation and functions. CD14+HLA-DR-/lo cells were significantly expanded in all MM patients, while undetectable in healthy donors. Suppressive activity was mediated by TGFβ, as suggested by functional experiments with neutralizing specific antibodies. In contrast, no involvement of arginase and iNOS pathways could be detected. CD14+HLA-DR-/lo cells, as well as spontaneous ex- vivo release and plasma levels of TGFβ, were augmented after administration of the HSPPC-96/GM-CSF vaccine. Interestingly, the expansion of suppressive CD14+ monocytes was associated to the inability to mount a significant CD8-mediated T cell response upon vaccination. On the other hand, no quantitative or qualitative enhancement of the CD14+HLA-DR-/lo suppressive cell population was observed in patients receiving a non-GM-CSF based vaccine. Conclusions: CD14+HLA-DR- /lo cells exerting TGFβ-mediated immune suppression may represent a new subset of myeloid suppressive cells, potentially expandable by the administration of GM-CSF-based vaccines in melanoma patients. [Table: see text]


2021 ◽  
Vol 66 (2) ◽  
pp. 218-230
Author(s):  
T. A. Aristova ◽  
E. V. Batorov ◽  
V. V. Sergeevicheva ◽  
S. A. Sizikova ◽  
G. Yu. Ushakova ◽  
...  

Introduction. Multiple myeloma (MM) is a B-cell malignancy with clonal expansion of plasma cells in bone marrow. Highdose chemotherapy with autologous haematopoietic stem cell transplantation is among main consolidation therapies in MM. Myeloid-derived suppressor cells (MDSCs) are immature myeloid-accompanying cells able to suppress the immune response. The administration of granulocyte colony stimulating factor (G-CSF) to mobilise haematopoietic stem cells (HSCs) increases the MDSC count in peripheral blood (PB).Aim — to study MDSC subsets in PB of remission MM patients and their incidence dynamics at HSC mobilisation.Methods. The study surveyed 35 MM patients prior to and after HSC mobilisation. The counts of granulocytic (G-MDSCs; Lin–HLA-DR–CD33+ CD66b+), monocytic (М-MDSCs; CD14+ HLA-DRlow/–) and early MDSCs (E-MDSCs; Lin–HLA-DR– CD33+ CD66b–) were estimated in flow cytometry.Results. Remission MM patients differed from healthy donors in higher relative counts of G-MDSCs (Lin–HLA-DR– CD33+ CD66b+) and increased relative and absolute counts of М-MDSCs (CD14+ HLA-DRlow/–). М-MDSCs significantly outnumbered G-MDSCs. MDSC subset counts were elevated in complete response (CR) and very good partial response (VGPR), as well as in partial response (PR). Higher relative MDSC counts were associated with greater pretreatment (2–3 lines of chemotherapy). After HSC mobilisation with cyclophosphamide 2–4 g/m2 + G-CSF (filgrastim 5 μg/kg/day), the median relative E-MDSC and M-MDSC counts increased by 2.3 and 2.0 times, respectively, while the relative G-MDSC count raised 46-fold perturbing the MDSC subset balance.Conclusion. Remission MM patients had the increased relative G-MDSC and both relative and absolute M-MDSC counts compared to donors. A greater patient pretreatment was associated with higher relative G-MDSC counts. Treatment response (CR/VGPR vs. PR) was not coupled with MDSC count variation. The G-CSF-induced HSC mobilisation entailed a significant expansion of all three MDSC subsets in PB.


Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 72-72
Author(s):  
Ke Wang ◽  
Meng Lv ◽  
Ying-Jun Chang ◽  
Xiang-Yu Zhao ◽  
Xiao-Su Zhao ◽  
...  

Abstract Introduction Myeloid-derived suppressor cells (MDSCs) are proposed to control graft-versus-host disease (GVHD) in allogeneic hematopoietic stem cell transplantation (allo-HSCT). However, the definition of human MDSCs has not yet reached consensus. Granulocyte colony-stimulating factor (G-CSF) has been routinely used to mobilize stem cells to peripheral blood in healthy donors. It was also recognized as a novel mediator of T-cell tolerance. However, the effects of G-CSF administration on donor-derived MDSCs and the further regulatory effects of these MDSCs on GVHD remained unclear. Amis The aim of this study is to evaluate the in vitro and in vivo effects of G-CSF expanded, donor-derived MDSCs (HLA-DR-/lowCD16-CD33+) in preventing acute GVHD after allo-HSCT. Methods The frequency and cell numbers of different kinds of MDSCs in peripheral blood before and after G-CSF administration from 10 healthy donors were analyzed by flow cytometry. Cells morphological features were detected by May-Grünwald-Giemsa cytospin. Secondly, the suppressive and regulatory functions of HLA-DR-/lowCD16-CD33+ population on CD3+ T cells were assessed via in vitro experiments. A humanized xenogeneic acute GVHD model was established to determine whether this population could prevent acute GVHD in vivo. Furthermore, a clinical prospective cohort study enrolled one hundred consecutive transplant recipients was performed to assess the effects of HLA-DR-/lowCD16-CD33+ contained in HSC grafts on the occurrence of acute GVHD. Results The findings of this study include: First, a novel phenotype of HLA-DR-/lowCD16-CD33+ MDSCs with suppressive function and morphological features similar to those of immature monocyte was identified. The median of percentages of this subset were significantly increased both in peripheral blood (PB, 6.5% vs. 4.6%, P=0.0122) and peripheral blood stem cells harvest (PBSCs, 15.5% vs. 4.6%, P<0.0001) after treating healthy donors with G-CSF than those of PB before mobilization. The median of percentage of interleukin-10 (IL-10) and transforming growth factor beta (TGF-β) positive cells among HLA-DR-/lowCD16-CD33+ population were both significantly higher than those of PB before mobilization. (IL-10+, 10.1% vs.0.62%, P=0.002; TGF-β+, 60.24% vs. 10.39%, P=0.0003). Donor-derived HLA-DR-/lowCD16-CD33+population inhibited the proliferation of T cells in a TGF-β-dependent manner. In vitro cell co-culture experiments also showed that this MDSCs subset could promote regulatory T cells (Treg, CD4+CD25+Foxp3+) expansion and induce T helper 2(Th2, CD4+IL-4+) differentiation (The median of percentage of Treg in co-culture with MDSCs group, 21.4% vs. without MSDCs group, 8.35%, P=0.0048. The median of fold change of Th2/Th1 in co-culture with MDSCs group, 1.35 vs. without MSDCs group 0.98, P=0.0159. The median of fold change of Th2/(Th1+Th17) in co-culture with MDSCs group, 1.28 vs. without MSDCs group 1.00, P=0.0095. Th1 (CD4+IFNγ+), Th17 (CD4+IL-17A+)). Second, we demonstrated that these cells could prevent acute GVHD in a humanized mouse model. Adoptive transfer human G-CSF-mobilized HLA-DR-/lowCD16-CD33+ cells significantly prolonged the survival and ameliorated the weight loss and tissue damage in GVHD mice. Third, clinical cohort results showed that the number of HLA-DR-/lowCD33+CD16- cells in the donor graft was the only independent risk factor inversely correlated with the incidence II-IV acute GVHD in recipients (HR 0.388, 95% CI: 0.158-0.954, P=0.039). Conclusion Our results suggest that MSDCs with HLA-DR-/lowCD16-CD33+ phenotype in G-CSF-mobilized PBSCs have monocytic features and immune-regulatory properties, which could alleviate acute GVHD in the allo-HSCT settings. Key words: Myeloid-derived suppressor cells; granulocyte colony-stimulating factor; graft-versus-host disease Figure Figure. Disclosures No relevant conflicts of interest to declare.


2020 ◽  
Vol 19 (3) ◽  
pp. 65-67
Author(s):  
A. V. Ponomarev ◽  
V. A. Misyurin ◽  
M. A. Baryshnikova

Introduction. Immunoregulatory functions of myeloid-derived suppressor cells have been extensively studied over the recent decades. Additionally, myeloid-derived suppressor cells have been investigated as a prognostic factor.Objective. To optimize the measurement of monocytic myeloid-derived suppressor cells in the peripheral blood of patients with B-cell chronic lymphocytic leukemia.Materials and methods. The number of myeloid-derived suppressor cells with CD14+HLA-DRlow/–-phenotype was determined in the peripheral blood of patients with B-cell chronic lymphocytic leukemia and healthy donors by flow cytometry. The measurement was carried out at two points, which differed in the concentration of anti-HLA-DR antibodies − 15 and 4 μl.Results. The median amount of myeloid-derived suppressor cells in the peripheral blood of B-cell chronic lymphocytic leukemia patients with 15 μl of anti-HLA-DR antibody was 1.9 %, and with 4 μl of antibody concentration – 7 %. Healthy donors had that median of 0.15 % with 15 μl of antibody and 0.3 % with 4 μl concentration.Conclusion. The number of CD14+HLA-DRlow/–-cells in the blood of patients with B-cell chronic lymphocytic leukemia is sensitive to the concentration of the HLA-DR antibody.Compliance with patient rights and principles of bioethics. The study protocol No 3 of 13.02.2020 was approved by the biomedical ethics committee of Research Institute of Experimental Diagnostics and Therapy of Tumors N.N. Blokhin National Medical Research Center of Oncology of the Ministry of Health of the Russian Federation. All patients gave written informed consent to participate in the study.


Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 1831-1831
Author(s):  
Alessandra Romano ◽  
Nunziatina Parrinello ◽  
Calogero Vetro ◽  
Piera La Cava ◽  
Annalisa Chiarenza ◽  
...  

Abstract Abstract 1831 Introduction In Multiple Myeloma (MM), but not in the monoclonal gammopathy of unknown significance (MGUS), the immune function is impaired as consequence of an immunologically hostile microenvironment and cellular defects, including reduction of immuno-surveillance and T-cell immunoparesis. We conducted an study focused on the myeloid compartment in MM, and its role in the progression from MGUS to MM. Methods Between January 2009 and April 2011 peripheral blood obtained from 60 consecutive newly diagnosed MM and 70 MGUS plus 30 healthy subjects was studied for evaluation of myeloid subpopulations and lymphoid paresis. Myeloid dysfunction was evaluated as percentage and absolute count of circulating myeloid suppressor cells (MDSC) in peripheral blood assessed by flow cytometry as follows: im-MDSC (CD34+/CD11b+/CD13+/CD14-/ HLA-DR-/CD45+), neutrophilic-like N-MDSC (CD11b+/CD13+/CD15+/CD14-/HLA-DR-/Lin-) and monocytic-like mo-MDSC (CD14+/HLA-DRlow/-). Myeloid function was evaluated by phagocytic activity using a commercially available kit (Phagotest R). Further, we investigated whether MM-neutrophils were able to induce anergy in T-cells. Neutrophils isolated from healthy donor (N=6), MGUS (N=3) or MM (N=6) peripheral blood (PB) were co-cultured with T-lymphocytes obtained from healthy donors. Expression of markers of activation in response to stimulation with PHA-P for 2 hours was assessed by flow cytometry as antigen density expressed as normalized mean of fluorescence intensity (N-MFI) of CD71 at 48 hours. Results The capability of phagocytosis of in neutrophils and monocytes from MM patients at diagnosis was significantly reduced compared to healthy subjects (p<0.001) and MGUS (p<0.0001). While the mature suppressive N-MDSC subset was not increased in MGUS and MM patients, the mo-MDSC subpopulation showed an increasing trend from healthy donors through MM (p=0.06) and the im-MDSC subset was significantly higher in MM vs healthy (p=0.002) and MGUS (p=0.001). After PHA-P stimulation, expression of CD71 (a marker of activation) in normal T-lymphocytes was increased (2954 ± 240.6 arbitrary units, au), and it was reduced (751.3 ± 30.48 au, p=0.0001) when co-coltured with MM-neutrophils, while no differences were evident in co-colture with MGUS- (2783 ± 206.1 au, p=0.61) or healthy donors-neutrophils (2588 ± 135.4, p=0.38). Conclusion Taken together, our findings suggest that in MM but not in MGUS there is a myeloid cell dysfunction that is correlated to impairment of T- cell arm. These alterations may have a role in the development of MM. Disclosures: No relevant conflicts of interest to declare.


2012 ◽  
Vol 30 (15_suppl) ◽  
pp. e19050-e19050
Author(s):  
Christiane Meyer ◽  
Laurene Cagnon ◽  
Nicole Montandon ◽  
Grégoire Berthod ◽  
Loredana Leyvraz ◽  
...  

e19050 Background: Myeloid derived suppressor cells (MDSC) are key immunosuppressive cells enriched in peripheral blood during chronic inflammation. While these cells have been extensively studied in mice, their human counterparts are less well characterized. Several MDSC populations have been identified in cancer patients, depending on tumor type and experimental settings. MDSC include immature macrophages, granulocytes and dendritic cells, at different degree of maturation, from immature CD33+, to mature CD14+ and CD15+HLA-DR- cells. The goal of this study was to characterize myeloid cells in melanoma patients compared with healthy donors (HD) to identify inflammation-mediated alterations involved in melanoma progression. Methods: PBMC were isolated by Lymphoprep gradient centrifugation from fresh blood samples of patients with malignant melanoma. We performed 9-color FACS staining of the freshly isolated cells. Results: CD15+ granulocytic MDSC are enriched in the mononuclear cell layer after gradient centrifugation, together with the CD14+ monocytic MDSCs. They display significantly different sedimentation abilities compared with neutrophils. Furthermore, CD14 and CD15 were partially co-expressed by the monocytic and granulocytic MDSC subsets, respectively. Our data show that CD14+HLA-DR- monocytic and CD15+HLA-DR- granulocytic MDSC were significantly enriched in peripheral blood of metastatic melanoma patients, regardless of whether or not they received any prior therapy for metastatic melanoma. The more immature CD33+CD11b- subset was found at significantly lower frequencies in melanoma patients compared with HD. We found a trend for accumulation of non-classical CD14+CD16+ monocytes. However, the increased percentages did not differ significantly from HD. The frequencies of classical CD14+CD16- monocytes were unchanged. Conclusions: Melanoma is associated with increased frequencies of CD14+ monocytic and CD15+ granulocytic MDSC, and decreased frequencies of the more immature CD33+CD11b- cells. This finding demonstrates tumor-mediated changes in the composition of myeloid cells, which could influence response to treatment and clinical behavior of the disease.


2020 ◽  
Vol 35 (12) ◽  
pp. 2677-2691
Author(s):  
Congcong Li ◽  
Chao Chen ◽  
Xiaomin Kang ◽  
Xiaoxin Zhang ◽  
Si Sun ◽  
...  

Abstract STUDY QUESTION Do decidua-derived factors stimulate the conversion of circulating neutrophils to polymorphonuclear myeloid-derived suppressor cells (PMN-MDSCs) in early human pregnancy? SUMMARY ANSWER Circulating neutrophils can acquire PMN-MDSC-like phenotypes and function via phosphorylated signal transducer and activator of transcription 5/programmed death ligand 2 (pSTAT5/PD-L2) signalling after stimulation with decidua-derived granulocyte macrophage colony-stimulating factor (GM-CSF). WHAT IS KNOWN ALREADY PMN-MDSCs are an important immunoregulatory cell type in early pregnancy. Neutrophils are of high heterogeneity and plasticity and can polarize to immunosuppressive PMN-MDSCs upon stimulation. STUDY DESIGN, SIZE, DURATION For analysis of myeloid-derived suppressor cell (MDSC) subset proportions, 12 endometrium tissues and 12 peripheral blood samples were collected from non-pregnant women, and 40 decidua tissues and 16 peripheral blood samples were obtained from women with normal early pregnancy undergoing elective surgical pregnancy termination for nonmedical reasons with gestation age of 6–10 weeks. Twenty-nine decidua tissues were collected for isolation of CD15+ PMN-MDSCs. Twenty endometrium tissues and 30 decidua tissues were collected for cytokine analysis, immunohistochemistry or neutrophil stimulation. Peripheral blood samples were obtained from 36 healthy donors for isolation of CD3+ T cells and CD15+ neutrophils. PARTICIPANTS/MATERIALS, SETTING, METHODS The proportion of MDSC subsets in the decidua and peripheral blood of normal early pregnancy, endometrium and peripheral blood of non-pregnant women was analysed by flow cytometry. The phenotypes and function of decidual PMN-MDSCs and circulating neutrophils were compared by flow cytometry. Circulating neutrophils were stimulated with decidual explant supernatant (DES) and the phenotypes were measured by flow cytometry and immunofluorescence. The suppressive capacity of decidual PMN-MDSCs and DES-conditioned neutrophils was analysed by flow cytometry with or without anti-programmed cell death-1 (PD-1) antibody. Cytokines from DES and endometrial explant supernatant (EES) were detected by a Luminex assay. GM-CSF expression was determined by ELISA and immunohistochemistry. Neutrophils were stimulated with DES, EES, DES with anti-GM-CSF antibody or EES with GM-CSF. CD11b, lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1), PD-L2 and pSTAT5 expression were measured by flow cytometry. MAIN RESULTS AND THE ROLE OF CHANCE The frequency of PMN-MDSCs was significantly increased in the decidua of early pregnancy compared with peripheral blood of non-pregnant women, the endometrium of non-pregnant women or peripheral blood during early pregnancy. Decidual PMN-MDSCs suppressed T-cell proliferation and cytokine production. Phenotypes of decidual PMN-MDSCs were similar to mature activated neutrophils. DES-induced CD11b, LOX-1, PD-L2 expression and STAT5 phosphorylation in neutrophils. The PD-L2 expression in neutrophils was dependent on STAT5 phosphorylation. Both decidual PMN-MDSCs and DES-conditioned neutrophils suppressed T-cell proliferation via PD-1 signalling. GM-CSF was up-regulated in the decidua and induced CD11b, LOX-1 and PD-L2 expression on neutrophils. DES significantly induced CD11b, LOX-1, PD-L2 expression and STAT5 phosphorylation. Anti-GM-CSF antibody remarkably blocked such stimulation in neutrophils. EES did not induce CD11b, LOX-1, PD-L2 expression or STAT5 phosphorylation, while GM-CSF treatment sufficiently stimulated CD11b, LOX-1, PD-L2 expression and STAT5 phosphorylation in neutrophils. LARGE SCALE DATA N/A LIMITATIONS, REASONS FOR CAUTION The study was based on in vitro experiments and we were not able to evaluate neutrophils differentiation to PMN-MDSCs in other sites before entering the maternal–foetal interface due to the limited availability of human samples. This needs to be explored using murine models. WIDER IMPLICATIONS OF THE FINDINGS This is the first study demonstrating that decidual PMN-MDSCs are a group of immunoregulatory cells with mature status, and that neutrophils can be induced to a PMN-MDSC-like phenotype with decidua-derived GM-CSF via pSTAT5/PD-L2 signalling. This study indicates that GM-CSF can facilitate immune tolerance of early pregnancy through regulating PMN-MDSCs and further provides a potential role of GM-CSF in prevention and treatment for pregnancy complications. STUDY FUNDING/COMPETING INTEREST(S) This work was supported by the National Natural Science Foundation of China (81671481) and National Natural Science Foundation of China (81871179). All authors have no competing interests to declare.


Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 1032-1032
Author(s):  
Stefanie AE Held ◽  
Annkristin Heine ◽  
Julia Wolf ◽  
Solveig Daecke ◽  
Anita Bringmann ◽  
...  

Abstract Abstract 1032 Myeloid derived suppressor cells (MDSC) play an important role in the regulation of immune responses by suppressing the function of antigen presenting cells and T cells. In humans several populations of MDSC with different phenotypes were characterized due to their distinct immunosuppressive function. However, the origin and development of these cells is not well understood. We observed that incubation of peripheral blood monocytes with IL-10 during their differentiation to dendritic cells (DC) in the presence of GM-CSF and IL-4 results in the generation of an APC population with dramatically reduced stimulatory capacity and a CD14+ and HLA-DR low phenotype (IL-10-APC) similar to the recently described human MDSC subpopulation. In coincubation experiments we found that the addition of these cells to immature or LPS activated DC generated from peripheral blood monocytes resulted in a cell number dependent inhibition of their stimulatory capacity in the mixed lymphocyte reaction assay. Furthermore, these IL-10-APCs reduced the expression of CD1a and costimulatory molecules on DC as well as their activation by LPS characterized by diminished expression of maturation markers including CD83, CD80, CD86 or CD40. IL-10-APC almost completely abolished the secretion of cytokines and chemokines by mature and immature DC involved in T cell stimulation and migration such as TNF-a, IL-6, MIP-1a or Rantes. These effects were not due to induction of IL-10 production and were not observed when purified CD14+ monocytes were used as a control in the experiments. In order to analyze the possible mechanisms and molecules involved in these inhibitory effects we found that IL-10-APC expressed higher levels of PD-1, GITR, GITRL and osteoactivin, an immunosuppressive molecule that was shown to inhibit the function of T cells. The effects mediated by these molecules were further confirmed by utilizing blocking antibodies. Interestingly, addition of IL-10-APC to mature or immature DC induced an increased expression of osteoactivin and its corresponding receptor syndecan 4 on DC thus demonstrating that osteoactivin mediates its effects by upregulating its own receptor. In the next set of experiments we isolated the CD14+ HLA-DR low cell population from buffy coats of healthy donors. We found, that these cells similar to the IL-10-APCs express high levels of osteoactivin and syndecan-4 that can be further upregulated by the addition of IL-10. Our results demonstrate that osteoactivin mediates its inhibitory effects by induction of its cognate receptor syndecan 4. In addition, cells with the phenotype and function of MDSC can differentiate from human peripheral blood monocytes in the presence of GM-CSF, IL-4 and IL-10. This immunosuppressive cell population can easily be generated in vitro and might be applied for the treatment of patients with GVHD or autoimmune disorders. Disclosures: No relevant conflicts of interest to declare.


2006 ◽  
Vol 24 (18_suppl) ◽  
pp. 8034-8034
Author(s):  
S. L. Ketchum ◽  
B. Cole ◽  
K. Margolin ◽  
D. McDermott ◽  
T. Crocenzi ◽  
...  

8034 Background: Lymphocyte depletion followed by homeostatic recovery has been shown to break tumor-specific tolerance. We have initiated a clinical trial of chemotherapy-induced lymphodepletion followed by high-dose (HD) IL-2 + GM-CSF in metastatic melanoma (MM) patients (pts). Methods: Pts with PS 0–1, normal organ function and with measurable MM were treated with intravenous cyclophosphamide 60 mg/kg (day 1–2), fludarabine 25 mg/m2 (day 3–7) followed by two 5-day (d) courses of intravenous HD bolus IL-2 600,000 IU/kg (d 8–12 and 21–25) and daily subcutaneous administration of GM-CSF 250 mcg/m2 (d 8 until granulocyte recovery). Results: 8 pts are presently evaluable in this first stage of accrual to confirm safety and immunomodulation. A mean of 25/28 IL-2 doses were delivered. All pts experienced transient myelosuppression with ANC < 500 cells/mm3 for a median of 7d (range 5–11d) and platelets <50,000/mm3 for a median of 5.5 days (range 0–7d). Pts exhibited reversible capillary leak associated with high-dose IL-2. With the exception of myelosuppression, no grade 4 toxicities occurred. All pts experienced neutropenic fever and 2 developed line infections. CD4+/CD25high/CD62L+ T cells rebounded by d 14, peaked around d 28 and returned to baseline by d 85. CD8+/CD28- T cells recovered to levels lower than baseline for the first 28d but then showed persistent elevation through d 113. Skewing of T-cell populations based on TCR β chain expression was observed. One pt achieved complete response, 2 achieved partial responses, and 5 progressed. Conclusions: Lymphodepletion followed by high-dose IL-2 can be safely administered, affects immune reconstitution, and has activity in MM that may be useful as a platform for enhancing immunotherapeutic strategies. The trial continues to accrue in order to better estimate antitumor activity and immunomodulation. No significant financial relationships to disclose.


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