Absolute Count of Myeloid Derived Suppressor Cells (MDSC) Is Able to Predict the Response to Early-PET In Hodgkin Lymphoma

Abstract Abstract 3882 Inflammation dominates both the histological and the clinical pictures of Hodgkin's Lymphoma (HL) and there are several clues that accessory cells (neutrophils, macrophages, and lymphocytes) have an important role in the development and progression of the disease. Recent studies have also highlighted the importance of interim PET (after 2 cycles of chemotherapy) as the most important prognostic factor for HL. Indeed, the positivity of interim PET is linked to the persistence of the reactive microenvironment that promotes tumor cells survival. CD68+ tumour associated macrophages have been recently identified as new marker of disease and their putative progenitors in peripheral blood are identified as Myeloid Derived Suppressor Cells (MDSC). This subpopulation of cells has been studied in some solid tumors where it has been documented its ability to suppress T-cell immune responses by several mechanisms, including expression of arginase and nitric oxide synthase. In order to identify an additional HD marker with prognostic significance, we evaluated 35 HL patients for circulating levels of MDSC, identified as CD34+, CD45+, CD11b+, CD13+, CD14- in peripheral blood by flow cytometry at diagnosis and correlated lab findings to clinical features and response to early 18FDG-PET, performed after the 2nd cycle. We found that at diagnosis HL patients have higher levels of circulating MDSC when compared to matched for sex and age healthy controls (mean 3,66 ± 1,94/mmc vs 1,69 ± 0,87/mmc, p=0.0001). Absolute number of MDSC was not correlated to markers of inflammation (ferritin, ESR, CRP,) tumor burden (stage, IPS, presence of bulky disease) and SUV at diagnosis PET. However, an interesting correlation was found between MDSC count at diagnosis and positivity of interim PET: all patients with a positive interim PET (5/35) had increased MDSC count at diagnosis and 5/7 patients with a count larger than 4.5 cells/uL had a positive early PET, with documented progression/relapse of disease for 4 of them. In order to confirm the immunosuppressive abilities of MDSC, we co-cultured myeloid cells (isolated by CD33+ or CD66+) from three HL patients, together with lymphocytes obtained by Ficoll-Hypaque from healthy donors and we found that lymphocytes were unable to become effectors after stimulation with PMA as documented by reduction of CD25, CD69 expression and increase of CD62L in comparison with control lymphocytes incubated with PHA alone. In conclusion, MDSC 1) are increased in peripheral blood of HL patients at diagnosis 2) correlate with interim PET 3) have a strong prognostic value, that is earlier and more easily accessible than interim PET 4) represent a paradigma of how a myeloid compartment may favour the development of a lymphoid neoplasia through T-cell impairment. Disclosures: No relevant conflicts of interest to declare.

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Myeloid-Derived Suppressor Cells in Patients with Hodgkin Lymphoma.

Blood ◽

10.1182/blood.v114.22.3662.3662 ◽

2009 ◽

Vol 114 (22) ◽

pp. 3662-3662

Author(s):

Nunziatina Parrinello ◽

Piera La Cava ◽

Daniele Tibullo ◽

Cesarina Giallongo ◽

Orazio Di Bartolo ◽

...

Keyword(s):

Flow Cytometry ◽

Hodgkin Lymphoma ◽

Peripheral Blood ◽

Mononuclear Cells ◽

Conflicts Of Interest ◽

Suppressor Cells ◽

Cell Number ◽

Myeloid Derived Suppressor Cells ◽

Peripheral Blood Mononuclear ◽

Hla Dr

Abstract Abstract 3662 Poster Board III-598 Background Immune suppression and angiogenesis are mechanisms key to tumour growth and progression. Myeloid-derived suppressor cells (MDSC) are a heterogeneous population of cells of myeloid origin and include immature macrophages, dendritic cells (DC) and other myeloid cells. In mice are phenotypically characterized as CD11b+Gr-1+ cells, while in human they have an immature phenotype, including lineage negative (Lin-), CD14-, HLA-DR-, CD15+, CD34+, CD11b+, CD33+, and CD13+ cells. MDSC reduce activated T-cell number and inhibit their function through different mechanisms including: L-arginine metabolism, nitric oxide (NO), up-regulation of reactive oxygen species (ROS), and secretion of immunosuppressive cytokines. MDSC also promote tumor-dependent angiogenesis as well as tumor metastasis. Their accumulation has been described in patients affected by some solid tumors but information on haematological neoplasms are lacking. Our study investigated by flow cytometry the presence of MSDC in the peripheral blood of patients affected by Hodgkin Lymphoma (HL). Methods We studied 14 patients with HL at diagnosis and 10 age-matched healthy controls (HC). Peripheral blood mononuclear cells were stained with the following monoclonal antibodies:CD11b, CD13, CD14, CD34, CD45, for 20 minutes at room temperature. After lysing red cells, cells were analyzed by flow cytometry. Results we observed a increased number of MDSC (CD11b+,CD13+,CD34+,CD14-, CD45+) in the peripheral blood of patients with HL compared to HC (13,37 ± 17,77 ×109/l vs 1,45± 0,98 ×109/l, p=0,0007). We also found that patients with advanced-stage Hodgkin disease (III and IV) have higher number of MDSC, compared to patients stage I and II (p= 0,04). Conclusion These data suggest a role for myeloid-derived suppressor cells in promoting tumor cell proliferation in hodgkin lymphoma. Disclosures: No relevant conflicts of interest to declare.

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Myeloid Derived Suppressor Cells (MDSCs) Are Increased and Exert Immunosuppressive Activity In CML Patients At Diagnosis

Blood ◽

10.1182/blood.v122.21.2711.2711 ◽

2013 ◽

Vol 122 (21) ◽

pp. 2711-2711

Author(s):

Cesarina Giallongo ◽

Nunziatina Parrinello ◽

Daniele Tibullo ◽

Piera La Cava ◽

Alessandra Romano ◽

...

Keyword(s):

T Cell ◽

Western Blot ◽

Cell Function ◽

Conflicts Of Interest ◽

Myeloid Cells ◽

Suppressor Cells ◽

Myeloid Derived Suppressor Cells ◽

Immunosuppressive Activity ◽

Arginase 1

Abstract Introduction In some solid tumors it has been demonstrated that a subpopulation of myeloid cells, defined as “myeloid-derived suppressor cells” (MDSCs), plays an important role in inducing T cell tolerance by production of arginase 1 (arg1) that depletes microenvironment of arginine, an essential aminoacid for T cell function. Since chronic myeloid leukemia (CML) patients have high levels of immature myeloid cells it is of interest to investigate if these cells have MDSCs phenotype and activity. The aim of this study was to analyze MDSCs and investigate their activity in CML patients. Methods MDSCs were analyzed in peripheral blood (PB) of 20 healthy donors (HD) and 30 CML patients at diagnosis. In 21 patients MDSCs were also measured during TKI treatment. Granulocytic MDSCs (G-MDSCs) were identified as CD11b+CD33+CD14-HLADR- cells, while the monocytic MDSCs (Mo-MDSCs) as CD14+HLADR by cytofluorimetric analysis. Arg1 expression was assessed using real time PCR and Western Blot. Arg activity was measured in granulocyte lysates using a colorimetric test after enzymatic activation and arginine hydrolysis. Microvesicles (MV) were isolated from CML serum at diagnosis (n=5) by sequential ultracentrifugation. Results CML patients showed high levels of Mo- and G-MDSCs at diagnosis in comparison to HD (41±8 and 82,5±12,2% respectively for CML vs 9±2,1 and 55±5,3% for HD; p<0.001), while after TKIs therapy both subpopulations decreased, returning to normal values. T-reg (CD4+ CD25high Foxp3+ cells) were also significantly increased in CML patients at diagnosis in respect to HD (9±2% vs 6,1±0,8%, p<0.001) with a significant correlation with the percentage of Gr-MDSCs (r=0,6254; p<0.001). Both in PB and purified granulocytic cells, Arg1 expression showed a 30 fold increase in CML at diagnosis compared to HD (p<0.001) and decreased after therapy. The same data were confirmed by Western Blot analysis. Arg enzymatic activity in granulocytes resulted also increased in CML (n=10) compared to HD (n=10) (p<0.001). The suppressive function of CML G-MDSCs was demonstrated by their ability to inhibit the proliferation of CFSE+ HD T cells (p<0.001). In addition, an increase of Mo-MDSCs in vitro was observed after incubation of HD monocytes with CML sera (29±13%; p<0.0001) or MV (8±2,8%; p<0.05). Conclusions MDSCs are increased in CML patients at diagnosis and decrease during TKIs treatment. CML granulocytes have high arg1 activity and immunosuppressive activity. Moreover, CML serum as well as CML microvesicles increase the percentage of HD Mo-MDSCs. Disclosures: No relevant conflicts of interest to declare.

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Peripheral blood myeloid-derived suppressor cells reflect disease status in idiopathic pulmonary fibrosis

European Respiratory Journal ◽

10.1183/13993003.01826-2015 ◽

2016 ◽

Vol 48 (4) ◽

pp. 1171-1183 ◽

Cited By ~ 29

Author(s):

Isis E. Fernandez ◽

Flavia R. Greiffo ◽

Marion Frankenberger ◽

Julia Bandres ◽

Katharina Heinzelmann ◽

...

Keyword(s):

T Cell ◽

Lung Function ◽

Idiopathic Pulmonary Fibrosis ◽

Pulmonary Fibrosis ◽

Peripheral Blood ◽

Suppressor Cells ◽

Chronic Obstructive ◽

Mrna Levels ◽

Myeloid Derived Suppressor Cells ◽

Peripheral Blood Mononuclear

Idiopathic pulmonary fibrosis (IPF) is a fibroproliferative disease with irreversible lung function loss and poor survival. Myeloid-derived suppressor cells (MDSC) are associated with poor prognosis in cancer, facilitating immune evasion. The abundance and function of MDSC in IPF is currently unknown.Fluorescence-activated cell sorting was performed in 170 patients (IPF: n=69; non-IPF interstitial lung disease (ILD): n=56; chronic obstructive pulmonary disease (COPD): n=23; healthy controls: n=22) to quantify blood MDSC and lymphocyte subtypes. MDSC abundance was correlated with lung function, MDSC localisation was performed by immunofluorescence. Peripheral blood mononuclear cell (PBMC) mRNA levels were analysed by qRT-PCR.We detected increased MDSC in IPF and non-IPF ILD compared with controls (30.99±15.61% versus 18.96±8.17%, p≤0.01). Circulating MDSC inversely correlated with maximum vital capacity (r= −0.48, p≤0.0001) in IPF, but not in COPD or non-IPF ILD. MDSC suppressed autologous T-cells. The mRNA levels of co-stimulatory T-cell signals were significantly downregulated in IPF PBMC. Importantly, CD33+CD11b+ cells, suggestive of MDSC, were detected in fibrotic niches of IPF lungs.We identified increased MDSC in IPF and non-IPF ILD, suggesting that elevated MDSC may cause a blunted immune response. MDSC inversely correlate with lung function only in IPF, identifying them as potent biomarkers for disease progression. Controlling expansion and accumulation of MDSC, or blocking their T-cell suppression, represents a promising therapy in IPF.

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Role of Circulating Myeloid-Derived Suppressor Cell (MDSC) in Hodgkin Lymphoma (HL) Patients: Prospective Study

Blood ◽

10.1182/blood-2019-130852 ◽

2019 ◽

Vol 134 (Supplement_1) ◽

pp. 5232-5232

Author(s):

Olga Novosad ◽

Oleksandr Gorbach ◽

Oksana Skachkova ◽

Ian Pastushenko ◽

Kateryna Ulianchenko ◽

...

Keyword(s):

Prognostic Factor ◽

Peripheral Blood ◽

Conflicts Of Interest ◽

Prognostic Significance ◽

The Body ◽

Interim Pet ◽

Line Therapy ◽

Healthy Control ◽

High Level

Introduction. MDSC's are a heterogeneous population of bone marrow-derived myeloid progenitors including macrophages, granulocytes, dendritic cells and immature myeloid cells, which expand dramatically with tumour growth, and there are several clues have an important role in the disease progression. Recent studies have also highlighted interim PET as the most important prognostic factor for HL. The interim PET positivity may indicate that there is a reactive microenvironment promoting tumor cells survival. In this study we analyzed the prognostic significance of MDSC count together with PET in HL patients. Methods . The 29 primary HL patients (median age: 33, range 19-61 years; males: 15, females: 14) were included in the study from Apr 2018 until now. 62% of patients were diagnosed with early stages of HL, while 38% - with advanced stages. ABVD or BEACOPP (14/esc) were administered as a 1st-line therapy. Peripheral blood mononuclear cells (PBMC) were isolated on ficol density gradient from peripheral blood before treatment, interim after 2-3 chemotherapy cycles and after the end of treatment (EOT). The percentage of E-MDSCs subtype and lymphoid populations was measured by flow cytometry using CD11b, CD33, CD14, HLA-DR, CD34, CD45, CD3, CD4, Cd8, CD16, CD56 antibodies. Metabolic PET-CT imaging was performed to routine protocols using Deauville criteria for response assessment. Results. 93% of patients achieved remission (CR/PR) during follow-up period (median 11.6 months). All pts are still in follow-up. The count of E-MDSC was increased in HL patients (median 12.5%) compared to matched for sex and age healthy controls (median 11%) and was higher in non-responders (median 19.7%). We also found that E-MSDC count in HL patients significantly increases with age - 6.5% in patients under 40 years vs 19.8% in patients 40+ years, p=0.007. No significant correlations were found between the frequency of MDSC and clinicopathological factors, including gender, Ann Arbor Stage, B symptoms, IPI scores. The number of NK-T (CD3+CD16+CD56+) cells increased on 6.73 % after EOT compared to before treatment, p=0.009. Theoretically, this means that immunosuppression is reduced and the antitumor immune response of the body is improved. 93.1% (27/29) and 6.9% (2/29) of patients had 1-3 and 4-5 DS of the EOT, respectively (p < 0.05). We recorded one early relapse (11months) after the 1st line therapy - patient had high level of MDSCs before treatment and it remained high after iPET and EOT-PET. Additionally, pts with iPET 4DS have a greater number of E-MDSCs compared to healthy control and, when complete remission is achieved, their values return to be equal to healthy control. We found strong significant association between EOT-PET and level of E-MDSC after treatment. Thus, pts with EOT-PET-ve had lower expression E-MDSC vs EOT-PET+ve (3% vs 29% respectively, p=0.0007). May be in future it can be new prognostic factor for predict to relapse. Conclusion. Patients with HL have high level of expression MDSC. Biomarkers research and HL biology at its basis may potentially rise up to the challenge of sole clinical prognostic factors application. This potentially area for research but are as yet unproven and in need have prospective validation. Disclosures No relevant conflicts of interest to declare.

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Immunogenomic identification and characterization of granulocytic myeloid-derived suppressor cells in multiple myeloma

Blood ◽

10.1182/blood.2019004537 ◽

2020 ◽

Vol 136 (2) ◽

pp. 199-209 ◽

Cited By ~ 6

Author(s):

Cristina Perez ◽

Cirino Botta ◽

Aintzane Zabaleta ◽

Noemi Puig ◽

Maria-Teresa Cedena ◽

...

Keyword(s):

Multiple Myeloma ◽

T Cell ◽

Prognostic Significance ◽

Suppressor Cells ◽

Progression Free Survival ◽

Chromatin Accessibility ◽

Myeloid Derived Suppressor Cells ◽

Phenotypic Profile ◽

Promote Tumor Growth ◽

Mature Neutrophil

Abstract Granulocytic myeloid-derived suppressor cells (G-MDSCs) promote tumor growth and immunosuppression in multiple myeloma (MM). However, their phenotype is not well established for accurate monitoring or clinical translation. We aimed to provide the phenotypic profile of G-MDSCs based on their prognostic significance in MM, immunosuppressive potential, and molecular program. The preestablished phenotype of G-MDSCs was evaluated in bone marrow samples from controls and MM patients using multidimensional flow cytometry; surprisingly, we found that CD11b+CD14−CD15+CD33+HLADR− cells overlapped with common eosinophils and neutrophils, which were not expanded in MM patients. Therefore, we relied on automated clustering to unbiasedly identify all granulocytic subsets in the tumor microenvironment: basophils, eosinophils, and immature, intermediate, and mature neutrophils. In a series of 267 newly diagnosed MM patients (GEM2012MENOS65 trial), only the frequency of mature neutrophils at diagnosis was significantly associated with patient outcome, and a high mature neutrophil/T-cell ratio resulted in inferior progression-free survival (P < .001). Upon fluorescence-activated cell sorting of each neutrophil subset, T-cell proliferation decreased in the presence of mature neutrophils (0.5-fold; P = .016), and the cytotoxic potential of T cells engaged by a BCMA×CD3-bispecific antibody increased notably with the depletion of mature neutrophils (fourfold; P = .0007). Most interestingly, RNA sequencing of the 3 subsets revealed that G-MDSC–related genes were specifically upregulated in mature neutrophils from MM patients vs controls because of differential chromatin accessibility. Taken together, our results establish a correlation between the clinical significance, immunosuppressive potential, and transcriptional network of well-defined neutrophil subsets, providing for the first time a set of optimal markers (CD11b/CD13/CD16) for accurate monitoring of G-MDSCs in MM.

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Mesenchymal STEM CELLS Favor Tumor Growth By Generating Granulocyte-like Myeloid Derived Suppressor CELLS in CML Patients

Blood ◽

10.1182/blood.v126.23.4018.4018 ◽

2015 ◽

Vol 126 (23) ◽

pp. 4018-4018

Author(s):

Cesarina Giallongo ◽

Nunziatina L Parrinello ◽

Daniele Tibullo ◽

Claudia Bellofiore ◽

Piera La Cava ◽

...

Keyword(s):

Stem Cells ◽

Cell Proliferation ◽

T Cells ◽

Mesenchymal Stem Cells ◽

T Cell ◽

Peripheral Blood ◽

Suppressor Cells ◽

T Cell Proliferation ◽

Myeloid Derived Suppressor Cells ◽

Healthy Donors

Abstract INTRODUCTION. The complex interplay between cancer cells and immune system allows neoplastic cells to evade immune surveillance and expand. Recently, our and another group have demonstrated that a subpopulation of myeloid cells, defined as "granulocytic myeloid-derived suppressor cells" (G-MDSC), plays an important role for immune escape in chronic myeloid leukemia (CML) patients by reducing T cell activation. The aim of this study was to evaluate the influence of Mesenchymal stem cells (MSC) on generation of MDSCs by comparing CML MSCs (n=10) with healthy donors (HD) MSC (n=8). METHODS. G-MDSC (CD11b+CD33+CD14-HLADR- cells) were analyzed in peripheral blood (PB) of 20 healthy donors (HD) and 30 CML patients at diagnosis by cytofluorimetric analysis. Immuno-suppressive activity was tested through incubation of G-MDSC with autologous CFSE-labeled T cells and stimulation with phytohaemagglutinin (PHA). Controls included a positive T cell proliferation control (T cells plus PHA) and a negative one (T cells only). After three days, T cell proliferation was analyzed by flow cytometry. For G-MDSC generation, human peripheral blood mononucleated cells (PBMC) from HD were cultured alone and with MSC of CML (n=10) or HD (n=8) (1:100 ratio). After one week, G-MDSC were isolated using anti-CD66b magnetic microbeads and the phenotype was confirmed by cytofluorimetric analysis. Expression of ARG1, NOS2, PTGS2, TNFα, TGFβ, IL6, IL10, IL1β was also evaluated using real time PCR. RESULTS. Percentage of cells with a G-MDSC phenotype was greater in PB obtained from CML patients than HD (82.5±9.6% vs 56,2±5.4%, p<0.0001). G-MDSC were able to inhibit T cell proliferation compared to positive control (25±5% vs 48±7.6%, p=0.0057). To investigate if CML MSC may be involved in G-MDSC generation, we incubated HD PBMC with CML or HD MSC for one week. After magnetic isolation, we found that only CML MSC-educated G-MDSC acquired immune-suppressive ability, inhibiting T cell proliferation compared to G-MDSCs control (isolated from PBMC cultured in medium alone) (32±12% vs 63±5.9%, p=0.003). On the contrary, HD MSC-educated G-MDSC did not show any suppressive effect. We also found that CML MSC-educated G-MDSC expressed higher level of the following immune modulatory factors: TNFα (20.8±19.3, p=0.006), IL1β (47.3±25.2, p=0.001), PTGS2 (20.7±10.9, p=0.002) and IL6 (33.8±13.9, p=0.004) compared to HD MSC-educated G-MDSCs (arbitrarily 2-ΔΔCt value: 1). MSC WE also observed ane an up-regulation of PTGS2 (19±4.4, p=0.04), TGFβ (6±3, p=0.01) and IL6 (5±2.8, p=0.04) in CML MSCs at time 0 with a great variability among the patients (calculated value of 2-ΔΔCt in HD MSC was 1). After 48 h of co-culture with PBMC, CML MSC showed statistically significant up-regulation of ARG1 (23.5±11.9, p=0.02), TGFβ (4.8±3, p=0.04), IL10 (5.6±2.8, p=0.03) and IL6 (54.3±23, p=0.02) expression, suggesting that multiple mechanisms are involved in MDSC induction by CML MSC. CONCLUSION. Our work demonstrates that CML MSCs are able to activate MDSCs favoring cancer immune evasion in CML patients. Disclosures Palumbo: Novartis: Honoraria, Other: Advisory Board.

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The clinical significance of myeloid-derived suppressor cells in dengue fever patients

BMC Infectious Diseases ◽

10.1186/s12879-019-4574-2 ◽

2019 ◽

Vol 19 (1) ◽

Cited By ~ 3

Author(s):

Peng-Le Guo ◽

Ling-Hua Li ◽

Wen-Li Li ◽

Jin-Cun Zhao ◽

Feng-Yu Hu ◽

...

Keyword(s):

T Cell ◽

Dengue Fever ◽

Clinical Significance ◽

Peripheral Blood ◽

Suppressor Cells ◽

Cell Number ◽

Target Cells ◽

Healthy Controls ◽

Myeloid Derived Suppressor Cells ◽

Arginase 1

Abstract Background Myeloid-derived suppressor cells (MDSCs) play immunosuppressive roles in cancers and some infectious diseases; however, their role in dengue fever (DF) remains unknown. This study evaluated the clinical significance of MDSCs in DF patients. Methods This study comprised 178 non-severe DF patients, 20 non-dengue fever (NDF) controls, and 30 healthy donors. The DF patients were divided into the following five groups based on the fever duration from its onset to the day of sample collection: fever duration of 1–2, 3–4, 5–6, 7–8, and > 9 days. Among these DF patients, 14 were monitored for eight days, and their peripheral blood samples were collected every two days. The mononuclear cells were isolated and analyzed using flow cytometry. The correlation between the MDSCs and clinical and immunological indicators of the DF patients was evaluated using Spearman analysis. Results The count of the peripheral blood MDSCs, especially monocytic MDSCs, of the 178 DF patients were dramatically higher than those of the NDF and healthy controls, and remarkably decreased with the fever duration. Moreover, the MDSC count correlated with some indicators, including the dengue viral load (rho = 0.367, p < .001), body temperature (rho = 0.263, p = .005), prothrombin time (rho = 0.475, p < .001), CD4+ T cell number (rho = − 0.317, p < .001), CD8+ T cell number (rho = − 0.361, p < .001), “programmed cell death protein 1” (PD-1) (rho = − 0.347, p < .001), “T cell immunoglobulin domain and mucin domain-3” (Tim3) (rho = − 0.258, p = .001), interferon-α (IFN-α) (rho = 0.43, p < .001), and “regulated upon activation normal T-cell expressed and secreted” (RANTES) (rho = 0.278, p = .019). Furthermore, the level of arginase-1, but not nitric oxide, was higher in the DF patients than in the healthy controls and was closely related to the number of MDSCs (rho = 0.265, p = .024). Conclusions Our study reveals a significant correlation between MDSCs and DF clinical indicators, posing MDSCs as potential target cells for DF treatment.

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Osteoactivin Mediates the Inhibitory Effects of Myeloid Derived Suppressor Cells

Blood ◽

10.1182/blood.v124.21.2745.2745 ◽

2014 ◽

Vol 124 (21) ◽

pp. 2745-2745

Author(s):

Stefanie Andrea Erika Held ◽

Annkristin Heine ◽

Solveig Daecke ◽

Anita Bringmann ◽

Peter Brossart

Keyword(s):

T Cells ◽

T Cell ◽

Conflicts Of Interest ◽

Suppressor Cells ◽

Cell Phenotype ◽

Myeloid Derived Suppressor Cells ◽

Blood Monocytes ◽

Inhibitory Effects ◽

Cytokines And Chemokines ◽

Hla Dr

Abstract Myeloid derived suppressor cells (MDSC) play an important role in the regulation of immune responses by suppressing the function of antigen presenting cells (APC) and T cells. However, the origin and development of these cells in humans is not well understood. We observed that incubation of peripheral blood monocytes with IL-10 during their differentiation to dendritic cells (DC) 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 resulted in an inhibition of DC induced T cell proliferation in a mixed lymphocyte reaction. 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. 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. 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 the next set of experiments we isolated MDSC with the CD14+ HLA-DR low cell phenotype from buffy coats of healthy donors. We found, that these cells similar to the IL-10-APCs express high levels of osteoactivin that can be further upregulated by the addition of IL-10. In order to analyze the possible mechanisms and molecules involved in these inhibitory effects we found that IL-10-APC and isolated MDSC expressed higher levels of PD-1, PD-L1, GITR, GITRL and osteoactivin, an immunosuppressive molecule that was shown to inhibit the function of T cells. Inhibition of osteoactivin on MDSC by utilizing blocking antibodies restored the function of DC in co-incubation experiments. Recently, it was shown that ß-glucans can decrease the suppressive function of MDSCs via Dectin-1. In our experiments, activation of MDSC with Dectin-1 ligand curdlan reduced the expression of osteoactivin and PD-L1 thus explaining how ß-glucans reduce the inhibitory effects of MDSC. In contrast, incubation of MDSC with TLR 2,3,4 and 7/8 ligands upregultaed osteoactivin, PD-1 and PD-L1 on the cell surface. Our results demonstrate that osteoactivin is a key molecule that mediates the inhibitory effects of MDSC on DC function. Disclosures No relevant conflicts of interest to declare.

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Monocytic CCR2+ Myeloid Derived Suppressor Cells Promote Immune Escape by Limiting Activated CD8 T Cell Infiltration Into the Tumor Microenvironment

Blood ◽

10.1182/blood.v118.21.2171.2171 ◽

2011 ◽

Vol 118 (21) ◽

pp. 2171-2171

Author(s):

Alexander Lesokhin ◽

Tobias Hohl ◽

Taha Merghoub ◽

Daniel Hirschhorn-cymerman ◽

Eric G. Pamer ◽

...

Keyword(s):

T Cell ◽

Tumor Microenvironment ◽

Immune Escape ◽

Conflicts Of Interest ◽

Suppressor Cells ◽

Cd8 T Cell ◽

Myeloid Derived Suppressor Cells ◽

T Effector Cells ◽

Gm Csf

Abstract Abstract 2171 Myeloid derived suppressor cells (MDSC) are a heterogeneous population of cells that accumulate during tumor progression in a process driven by soluble factors such as granulocyte-macrophage colony stimulating factor (GM-CSF). These cells contribute to the suppressive nature of the tumor microenvironment and interfere with the functions of cytotoxic anti-tumor T effector cells. To date, MDSC heterogeneity has presented a barrier to studying the properties of individual MDSC constituents in vivo. Herein, we find that GM-CSF, a cytokine that promotes the numeric and functional development of monocytes, granulocytes and dendritic cells, and is frequently used as a vaccine adjuvant, is also critical for the expansion of a monocyte-derived MDSC population characterized by the expression of CD11b and the chemokine receptor CCR2. We demonstrate that these cells mediate T cell suppression in a contact dependent fashion and via the function of Arginase and inducible nitric oxide synthase, consistent with known MDSC functions. CD11b+CCR2 negative cells do not have suppressive capability despite also being expanded numerically by the actions of GM-CSF. Utilizing a toxin-mediated ablation strategy that targets CCR2-expressing cells, we demonstrate that monocytic MDSCs regulate activated CD8 T cell entry into the tumor site in vivo, thereby limiting the efficacy of immunotherapy. Our results extend observations on the dual role of GM-CSF in both stimulation and suppression of tumor immunity and suggest therapeutic targeting of monocytic MDSC could enhance the outcomes of immunotherapy. Disclosures: No relevant conflicts of interest to declare.

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Myeloid-Derived Suppressor Cells in Patients with Multiple Myeloma and Monoclonal Gammopathy of Undetermined Significance.

Blood ◽

10.1182/blood.v114.22.4890.4890 ◽

2009 ◽

Vol 114 (22) ◽

pp. 4890-4890

Author(s):

Nunziatina Parrinello ◽

Piera La Cava ◽

Daniele Tibullo ◽

Cesarina Giallongo ◽

Orazio Di Bartolo ◽

...

Keyword(s):

Multiple Myeloma ◽

Peripheral Blood ◽

Monoclonal Gammopathy ◽

Conflicts Of Interest ◽

Suppressor Cells ◽

Tumor Escape ◽

Myeloid Derived Suppressor Cells ◽

Tumor Resistance ◽

Cell Functions ◽

Undetermined Significance

Abstract Abstract 4890 Background Myeloid-derived suppressor cells (MDSC) are a heterogeneous population of cells of myeloid origin, and include immature macrophages, granulocytes, dendritic cells (DC) and other myeloid cells. In mice, are phenotypically characterized as CD11b+Gr-1+. Humans MDSC have an immature phenotype, including lineage negative (Lin-), CD14-, HLA-DR-, CD15+, CD34+, CD11b+, CD33+, and CD13+ cells. MDSC impair T-cell functions through secretion immunosuppressive cytokines, perturbation of the arginine metabolism by inducible nitric oxide synthase (iNOS), up-regulation of reactive oxygen species (ROS), therefore are considered an important tumor escape mechanism. These cells, also promote tumor-dependent angiogenesis as well as tumor metastasis, and to provide tumor resistance to antiangiogenic drugs. Their accumulation has been described in the peripheral blood of patients affected by breast, lung, renal and neck carcinoma, melanoma, chronic infections, inflammatory diseases, and traumatic stress. We investigate MSDC in patients with multiple myeloma (MM) and monoclonal gammopathy undetermined significance (MGUS) by flow cytometry Methods We studied 22 patients with MM at diagnosis, 20 patients with MGUS, and 10 healthy controls (HC). Results we observed that patients with MGUS showed the same number of MDSC (CD11b+,CD13+,CD34+,CD14-,CD45+) in the peripheral blood compared to HC (1,90±1,03/mmc, p=0,23). On the contrary, patients affected by MM showed a significant increase of MDSC vs HC (6,80±8,79/mmc vs 1,45± 0,98/mmc, p=0,003). Conclusion Our results suggest that these myeloid-derived suppressor cells, through their mechanisms immunesuppressive and proangiogenesis, could be involved in the progression of MGUS towards overt MM. Disclosures No relevant conflicts of interest to declare.

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