Myeloid-derived Suppressor Cells In Peripheral Blood Research Articles

Damage-Associated Molecular Patterns and Myeloid-Derived Suppressor Cells in Bronchoalveolar Lavage Fluid in Chronic Obstructive Pulmonary Disease Patients.

Myeloid-derived suppressor cells (MDSCs) are present in the human lung microenvironment, and they may be involved in the local inflammatory process in chronic obstructive pulmonary disease (COPD). Chronic inflammation in COPD may induce immunogenic cell death of structural airway cells, causing the release of damage-associated molecular patterns (DAMPs). DAMPs may activate the innate and adaptive immune system. The relationship between MDSCs and DAMPs in COPD is poorly described in the available literature. Objectives. (1) Assessment of MDSC percentage and DAMP concentration in bronchoalveolar lavage fluid (BALF) and peripheral blood. (2) Analysis of the relationship between MDSC percentage and chosen DAMPs. Patients and Methods. 30 COPD patients were included. Using monoclonal antibodies directly conjugated with fluorochromes in flow cytometry, MDSCs were assessed in BALF and peripheral blood. The concentration of DAMPs was estimated using sandwich ELISA. Using the Bradford method, the total protein concentrations were evaluated. Results. The percentage of MDSCs among MC in BALF correlated well with the concentration of defensin and heat shock protein 27. Assessing the percentage of MDSCs among all leukocytes in BALF, we revealed a significant correlation with the concentration of defensin, hyaluronic acid, and surfactant protein A. No dependencies occurred between DAMPs and MDSCs in peripheral blood. Conclusion. MDSCs and DAMPs occur in the COPD patient lung microenvironment. Significant correlations between them found in BALF may indicate their influence on the local inflammatory process in COPD. These relationships allow better understanding of the inflammatory process in COPD.

Prognostic Value of CD14+HLA-DRlow/- Myeloid Derived Suppressor Cells in Diffuse Large B Cell Lymphoma

To investigate the role of myeloid-derived suppressor cells (MDSC) in the prognosis of patients with diffuse large B cell lymphoma (DLBCL). The peripheral blood of 52 DLBCL patients and 30 healthy volunteers was collected. The CD14+HLA-DRlow/- was used as the immune marker for MDSC. The role of MDSC in the prognosis of DLBCL patients was analyzed by combination with the related clinicopathological data. The proportion of MDSC in peripheral blood of newly diagnosed DLBCL patients increased significantly (P＜0.01). The expression of MDSC in DLBCL patients was related with clinical staging, lactate dehydrogenase (LDH) level and IPI score (P＜0.01). There was no significant correlation with sex, age, and B symptoms. Univariate analysis showed that the clinical stage, serum LDH level, IPI score and MDSC level were the adverse factors affecting the overall survival (OS). Multivariate analysis showed that IPI score and MDSC level were independent risk factors for OS in DLBCL patients. MDSC can be used as an important index to evaluate the prognosis of DLBCL patients, contributing to evaluate the immune and tumor microenvironment of DLBCL patients.

PS1135 MONOCYTIC BUT NOT GRANULOCYTIC MDSCS INCREASE WITH IBRUTINIB BUT NOT ACALABRUTINIB TREATMENT IN EM‐TCL1 MICE WITH CLL, SUGGESTING A ROLE FOR ITK INHIBITION IN MONOCYTIC MDSCS

Background:Myeloid derived suppressor cells (MDSC) represent a heterogeneous population of immature myeloid cells with the ability to suppress T cell function and promote Treg expansion. In humans, CLL cells can induce the conversion of monocytes to MDSCs provoking their accumulation in peripheral blood (PB) 1. MDSCs include two major subsets granulocytic (Gr) and monocytic (M)‐MDSC. In mice, Gr‐MDSCs and M‐MDSC are defined as CD11b+Ly6G+Ly6Clo and CD11b+Ly6G−Ly6Chi, respectively. Both murine and human MDSCs express BTK. It has been demonstrated that treatment with the BTK inhibitor (BTKi), Ibrutinib modulates MDSC function in a murine breast cancer model and its use has been suggested for enhancing immune‐based therapies in solid tumors2.Aims:We aimed to determine the role of MDSCs in CLL engraftment and the impact of iIbrutinib and acalibrutinib (second generation BTKi) in these cell populations in vivo. CLL is associated with a tumour supported microenvironment and T cells exhibit multiple functional defects and features of exhaustion. These T cell defects in CLL are closely recapitulated in Em‐TCL1 (TCL1) mice, and are induced in healthy mice by adoptive transfer (AT) of murine CLL cells.Methods:To address this question in vivo C57/Bl6 animals 2.5 months of age were AT with 40x106 purified pooled TCL1 CLL B cells. When PB CLL load reach >10% animals were randomized (mean day 14) to either vehicle treatment (2% HPBD) Ibrutinib (0.15 mg/l in 2% HPBC) or Acalabrutinib treatment (0.15 mg/l in 2% HPBC) for 21 days. 15 animals per group were analysed. MDSC sub‐populations were monitored weekly and splenic cells were isolated and characterized by flow cytometry.Results:During CLL progression, the overall ratio of CD11b+ over non‐B cells significantly decreased in PB from 4 weeks post AT when compared to age‐matched WT controls (p < 0.0001). At the same time, the ratios of both Gr‐ and M‐MDSCs over non‐B cells were significantly decreased (p < 0.001) as the population of malignant CD19+CD5+ cells expanded in PB. After treatment, the CD11b+CD19− cell population was not affected by either ibrutinib or acalibrutinib treatments (ns) in spleens. There was an increased presence of M‐MDSCs after Ibrutinib treatment (p < 0.01), but not acalibrutinib (ns); whilst the presence of Gr‐MDSCs increased with both treatments (p < 0.001 and p < 0.05 respectively). Finally, the population of CD11b+F4/80+ macrophages had a higher increase with acalibrutinib (p < 0.001) than ibrutinib (p < 0.05) in spleens after treatment.Summary/Conclusion:Although MDSCs increase with CLL development in this model, the population of MDSC in PB disappears with CLL disease progression, likely due to the accelerated increment of the CLL population overtaking the tumour microenvironment. When TCL1 AT mice are treated with BTKis, the provoked clearance of CLL cells in secondary lymphoid organs allows the recovery of MDSCs at site. We speculate that the particular increase in M‐MDSC subpopulation in spleens is ITK dependant, since we only observe this after ibrutinib and not acalibrutinib treatment. This provides the rationale for our ongoing preclinical studies of these populations in response to BTKis currently used for the treatment of CLL.

CCR5/CCR5 ligand-induced myeloid-derived suppressor cells are related to the progression of endometriosis.

Immunological disorders have been reported to promote the progression of endometriosis. Several recent studies have shown that myeloid-derived suppressor cells (MDSC) drive the progression of endometriosis. The aim of this case-control study was to test whether CCR5 and its ligands drive MDSC accumulation and play a role in the progression of endometriosis. Thirty-six endometriosis patients and 20 controls were recruited. All subjects underwent laparoscopy. An ELISA kit was used to define CCR5 ligands in plasma and peritoneal fluid from endometriosis patients; flow cytometry was then used to characterize CCR5+MDSC in peripheral blood and peritoneal fluid. Data showed that endometriosis patients displayed a significantly higher production of plasma CCL3 (P = 0.046) and peritoneal fluid CCL3/5 (P = 0.042/0.036) compared with those from the uterine leiomyoma group. Furthermore, the concentrations of peritoneal fluid CCL5 were elevated in late stage patients compared with those from the uterine leiomyoma group. Accumulation of blood CCR5+Mo-MDSC was detected in endometriosis patients compared with those from both the ovarian dermoid cysts and uterine leiomyoma groups. Endometriosis patients also showed an elevation of CCR5+MDSC and CCR5+Mo-MDSC in peritoneal fluid samples compared with uterine leiomyoma samples. It was also found that enrichment of CCR5+MDSC (r = 0.6807; P < 0.0001) and CCR5+Mo-MDSC (r = 0.6893; P < 0.0001) were correlated with enhanced production of CCL5 in peritoneal fluid from endometriosis patients. This study showed that CCR5 and its ligands could drive the progression of endometriosis by enhancing the accumulation of MDSC. These findings might produce a promising treatment that targets CCR5+MDSC for endometriosis patients.

Myeloid-Derived Suppressor Cells in Lung Transplantation.

Myeloid-derived suppressor cells (MDSC) are a heterogeneous group of immune cells from the myeloid lineage. MDSCs expand in pathological situations, such as chronic infection, cancer, autoimmunity, and allograft rejection. As chronic lung allograft dysfunction (CLAD) limits long-term survival after lung transplantation (LTx), MDSCs may play a role in its pathophysiology. We assessed phenotype and frequency of MDSCs in peripheral blood from lung transplant recipients and its relationship to post-transplant complications and immunosuppression. Granulocytic (G)-MDSC were identified and quantified by flow cytometry of blood from 4 control subjects and 20 lung transplant patients (stable n = 6, infection n = 5; CLAD n = 9). G-MDSC functionality was assessed in vitro by their capability to block CD4 and CD8 T cell proliferation. More G-MDSC could be assessed using EDTA tubes compared to heparin tubes (p = 0.004). G-MDSC were increased in stable lung transplant recipients vs. non-transplant controls (52.1% vs. 9.4%; p = 0.0095). The infection or CLAD groups had lower G-MDSCs vs. stable recipients (28.2%p = 0.041 and 33.0%; p = 0.088, respectively), but were not different among CLAD phenotypes. G-MDSC tended to correlate with cyclosporine A and tacrolimus levels (r2 = 0.18; r2 = 0.17). CD4 and CD8 cells proliferation decreased by 50 and 80% if co-cultured with MDSCs (1:6 and 1:2 MDSC:T-cell ratio, respectively). In conclusion, circulating MDSCs are measurable, functional and have a G-MDSC phenotype in lung transplant patients. Their frequency is increased in stable patients, decreased during post-transplant complications, and related to level of immunosuppression. This study may pave the way for further investigations of MDSC in the context of lung transplantation.

The transcriptional profile of circulating myeloid derived suppressor cells correlates with tumor development and progression in mouse.

Myeloid derived suppressor cells (MDSCs) play key roles in cancer development. Accumulation of peripheral-blood MDSCs (PB-MDSCs) corresponds to the progression of various cancers, but provides only a crude indicator. We aimed toward identifying changes in the transcriptional profile of PB-MDSCs in response to tumor growth. CT26 colon cancer cells and B16 melanoma cells (106) were inoculated into peritoneal cavities of BALB/c mice and subcutaneously to C57-black mice, respectively. The circulating levels and global transcriptional patterns of PB CD11b+Ly6g+ MDSCs were assessed in control mice, and 4, 8, and 11 days following tumor cell inoculation. Although a significant accumulation of PB-MDSCs was demonstrated only 11 days following tumor induction, a pronounced transcriptional response was identified already on day 4 while the tumor was ~1 mm in size. Further transcriptional changes correlated with different stages of tumor growth. Key MDSC genes and canonical signaling pathways were activated along tumor progression. This phenomenon was demonstrated in both cancer models, and a consensus set of 817 genes, involved in myeloid cell recruitment and angiogenesis, was identified. The data suggest that the transcriptional signatures of PB-MDSC may serve as markers for tumor progression, as well as providing potential targets for future therapies.

The prognostic value of glycosylphosphatidylinositol-anchored 80 kD protein (GPI-80) positive myeloid derived suppressor cells (MDSCs) in peripheral blood of metastatic renal cell carcinoma (mRCC) patients.

601 Background: Myeloid derived suppressor cells (MDSCs) are found to play essential roles in various tumors and to associate with the prognosis of patients. However, the prognostic values of MDSCs in metastatic renal cell cancer (mRCC) are still undefined. Glycosylphosphatidylinositol-anchored 80 kD protein (GPI-80) is known as a regulator of Mac-1 (CD11b/CD18) and closely related with differentiation of myeloid cells. The object of our study was to interrogate the association of MDSCs in peripheral blood with clinical outcomes of mRCC patients by using GPI-80. Methods: Peripheral blood samples, collected from 23 mRCC patients before treatment and 16 healthy volunteers, were stained with several myeloid cell antigens such as CD16, CD15, CD33, and GPI-80 to mark neutrophils and monocytes. We measured the expression levels (mean of florescence intensity, MFI) and deviation (coefficient variation, CV) of myeloid antigens by flow cytometry. To investigate the immunosuppressive function of GPI-80 positive cells, reactive oxygen species (ROS) and LAP-1 (precursor of TGF-β1) were measured. The impact of the cell surface antigens on overall survival (OS) was evaluated using the univariate and multivariate Cox regression analysis. Results: The MFI or CV of GPI-80 on neutrophilic or monocytic cells were significantly difference in between patients and healthy volunteers. LAP-1 expression and ROS production in monocytic cells were increased in patients than in healthy volunteers, and correlated with expression of GPI-80 MFI (p = 0.0107 and p = 0.0381, respectively). Regarding the prognostic values, both GPI-80 CV of neutrophilic cells and GPI-80 MFI of monocytic cells were associated with poor OS of mRCC patients (p &lt; 0.01). Multivariate analysis showed that GPI-80 MFI of monocytic cells were independent unfavorable prognosis marker (HR 2.427, p = 0.044). Conclusions: These results showed that change of GPI-80 expression on myeloid cells in peripheral blood representing appearance of MDSCs was likely to be negative predictors in patients with mRCC.

CD11b + Ly6G + myeloid‐derived suppressor cells promote liver regeneration in a murine model of major hepatectomy

Liver regeneration depends on sequential activation of pathways and cells involving the remaining organ in recovery of mass. Proliferation of parenchyma is dependent on angiogenesis. Understanding liver regeneration-associated neovascularization may be useful for development of clinical interventions. Myeloid-derived suppressor cells (MDSCs) promote tumor angiogenesis and play a role in developmental processes that necessitate rapid vascularization. We therefore hypothesized that the MDSCs could play a role in liver regeneration. Following partial hepatectomy, MDSCs were enriched within regenerating livers, and their depletion led to increased liver injury and postoperative mortality, reduced liver weights, decreased hepatic vascularization, reduced hepatocyte hypertrophy and proliferation, and aberrant liver function. Gene expression profiling of regenerating liver-derived MDSCs demonstrated a large-scale transcriptional response involving key pathways related to angiogenesis. Functionally, enhanced reactive oxygen species production and angiogenic capacities of regenerating liver-derived MDSCs were confirmed. A comparative analysis revealed that the transcriptional response of MDSCs during liver regeneration resembled that of peripheral blood MDSCs during progression of abdominal tumors, suggesting a common MDSC gene expression profile promoting angiogenesis. In summary, our study shows that MDSCs contribute to early stages of liver regeneration possibly by exerting proangiogenic functions using a unique transcriptional program.-Nachmany, I., Bogoch, Y., Sivan, A., Amar, O., Bondar, E., Zohar, N., Yakubovsky, O., Fainaru, O., Klausner, J. M., Pencovich, N. CD11b+Ly6G+ myeloid-derived suppressor cells promote liver regeneration in a murine model of major hepatectomy.

Changes in the frequency of myeloid-derived suppressor cells after transarterial chemoembolization with gelatin sponge microparticles for hepatocellular carcinoma

PurposeA series of clinical studies have established the safety and efficacy of transcatheter arterial chemoembolization (TACE) with gelatin sponge microparticles (GSMs) in treating hepatocellular carcinoma (HCC). HCC can lead to obvious necrosis inside tumors, especially larger ones, although it is unclear whether such necrotic tumor tissue can induce favorable immune reactions against the tumor. Myeloid-derived suppressor cells (MDSCs) have immunosuppressive functions and are currently considered a very important cell type affecting tumor immunity. This study observed changes in MDSC frequency in peripheral blood before and after GSM–TACE to evaluate the effect on the immune function of HCC patients. MethodsEight patients diagnosed with HCC underwent GSM–TACE treatment in the Hepatobiliary Interventional Department of Beijing Tsinghua Chang Gung Hospital, Beijing, China; we followed up with the patients over a period of 30 days post-surgery. We used flow cytometry (FCM) to quantify the frequency of MDSCs in peripheral blood before TACE, 10 days after surgery and 30 days after surgery. ResultsMDSC frequency after GSM–TACE had a significant downward trend. Pre-TACE, it was 30.73% ± 11.93%, decreasing to 18.60% ± 11.37% at 10 days after operation. This decrease was not statistically significant (P > 0.05). MDSC frequency was even lower 30 days after TACE (7.63% ± 7.32%) than at 10 days after TACE (P < 0.05), and there was a significant difference compared with pre-TACE (P < 0.001). We evaluated tumor response at 30 days after GSM–TACE according to the Modified Response Evaluation Criteria in Solid Tumors (mRECIST), and all eight patients showed partial response (PR). ConclusionOur results confirmed that GSM–TACE was beneficial for improving anti-tumor immunity in the treatment of HCC.

Abstract IA10: PMN-MDSC and neutrophils: Tale of two cells in cancer

Abstract Myeloid cells are a critical component of the tumor microenvironment. In cancer, the myeloid compartment is dramatically affected, which is now considered as one of the major immunological hallmarks of cancer. Accumulation of immunosuppressive macrophages (MΦ), defective dendritic cells (DC) function and expansion of pathologically activated immune suppressive immature myeloid cells – myeloid-derived suppressor cells (MDSC) are major changes in the myeloid compartment in cancer. The total population of MDSC consists of three groups of cells: the most abundant (&amp;gt;75%) immature, pathologically activated neutrophils (PMN-MDSC); the less abundant population of pathologically activated monocytes – (M-MDSC). Tumor associated macrophages (TAM) and DCs can persist in tissues for a long time, whereas PMN-MDSC have short lifespan (&amp;lt; 48 hours) and are constantly replaced from bone marrow (BM). The role of MDSC in mouse tumor models is well established. In most of the studies PMN-MDSC were cells that expanded the most. In recent years, the clinical role of MDSC has emerged. Results showed positive correlation of MDSC in peripheral blood with cancer stage and tumor burden. In a meta-analysis, elevated MDSC in the circulation was found to be an independent indicator of poor outcomes in patients with solid tumors and predicting response to chemotherapy therapy, radiotherapy failure, and immunotherapy. It is widely accepted that the population of myeloid cells in cancer is heterogenic. It consists of cells able to exert antitumor and pro-tumorigenic activity. The nature of this heterogeneity is highly controversial. Some data suggested that PMN-MDSC in tumors may undergo polarization in situ, similar to that observed in TAM. Based on available data on the very short lifespan of MDSC in animal models and cancer patients as well as on functional data, we have postulated that at any given moment, myeloid cells in tissues are comprised of classically activated neutrophils (PMN) and monocytes, with pro-inflammatory and antitumor activity, and pathologically activated MDSC with potent immune suppressive and pro-tumorigenic activity. The balance between these cells defines the tumor microenvironment as immunosuppressive. This balance depends on the stage of cancer. It is equally plausible that in tissues, MDSC are present not in a binary state but in a range of functional states that are characterized by different markers and different functional activities. We will discuss evidence supporting this hypothesis. This question has a direct implication for cancer therapy. It is not clinically feasible to deplete the entire population of PMN and monocytes in cancer patients. However, if a specific group of functionally defined M-MDSC and PMN-MDSC is determined, then much more precise methods of therapeutic targeting could be developed. Potential approaches to such targeting are currently being investigated. Citation Format: Dmitry I. Gabrilovich. PMN-MDSC and neutrophils: Tale of two cells in cancer [abstract]. In: Proceedings of the Fourth CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; Sept 30-Oct 3, 2018; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2019;7(2 Suppl):Abstract nr IA10.

Myeloid-derived suppressor cells and tumor: Current knowledge and future perspectives.

The immunosuppressive features of tumor lesions participate not only as one of the major players inducing cancer progression but also a big challenge for effective immunotherapy. It has been found that immunosuppression associated with chronic inflammatory factors, such as growth factors, cytokines, and chemokines is generated by stroma and tumor cells. Chronic and exhaustive secretion of these mediators triggers the generation of myeloid-derived suppressor cells (MDSCs) demonstrating one of the key players engaged in tumor immunosuppression. In point of fact, direct cell-to-cell contact is a prerequisite for immunosuppressive functions of MDSCs. From the clinical perspective, the frequency of peripheral blood MDSCs is correlated with clinical stage and therapeutic response in various cancers. Furthermore, MDSCs are involved in chemoresistant settings. Altogether, it is a rational therapeutic approach to block the fierce cycle in which MDSCs are developed and infiltrated to favor cancer progression. In this review, we will summarize recent findings of MDSCs in tumor progression and discuss potential therapeutic strategies that could be evaluated in future clinical trials.

Circulating myeloid-derived suppressor cells: An independent prognostic factor in patients with breast cancer.

Evading immune destruction is a hallmark of cancer. Myeloid-derived suppressor cells (MDSCs), a heterogeneous population of myeloid immune cells, are thought to foster the establishment of an immunosuppressive tumor microenvironment, but it remains unclear how. This study aims to determine the levels of circulating MDSCs and their subpopulations and test their immunosuppressive functions in patients with breast cancer (BC).We analyzed the fractions of MDSCs in freshly isolated peripheral blood mononuclear cells of patients withBC and healthy donors using flow cytometry. Circulating MDSCs were further phenotyped using fluorescently labeled antihuman monoclonal antibodies. Coculture experiments revealed the effects of MDSCs on CD3+ T cell response. Moreover, we correlated circulating MDSC levels with clinicopathological features of patients with BC.We show that the fraction of HLA-DR - CD33 + MDSCs in peripheral blood is about 10-fold higher in patients with BC than in healthy control individuals. The levels of all MDSC subpopulations, including monocytic and granulocytic MDSCs, are significantly elevated. Coculture experiments of purified HLA-DR - CD33 + MDSCs and CD3 + T cells demonstrate that T cell proliferation is more effectively inhibited by BC patient-derived MDSCs than by healthy control MDSCs. Moreover, increased circulating MDSC levels robustly associate with advanced BC stage and positive lymph node status.By being more abundant and more effective T cell suppressors, BC patient-derived circulating MDSCs exert a dual immunosuppressive effect. Our findings pave the way to develop novel diagnostic and immunotherapeutic strategies, aimed at detecting and inhibiting MDSCs in patients with BC.

The Immunobiology of Receptor Activator for Nuclear Factor Kappa B Ligand and Myeloid-Derived Suppressor Cell Activation in Immunoglobulin G4-Related Sclerosing Cholangitis.

The primary function of myeloid-derived suppressor cells (MDSCs) is reflected in their immune modulatory role in several immune-mediated diseases. In immunoglobulin G4 (IgG4)-related disease (IgG4-RD), it has been hypothesized that there are selective regulatory defects that lead to a T helper 2 (Th2) bias immune response. Herein we have taken advantage of a large cohort of patients with IgG4-related sclerosing cholangitis (IgG4-SC), the most common extrapancreatic involvement of IgG4-RD, as well as controls consisting of primary sclerosing cholangitis, autoimmune hepatitis, and healthy volunteers, to study MDSCs. We report dramatically increased levels of receptor activator for nuclear factor kappa B ligand (RANKL) expression in serum and liver from patients with IgG4-SC compared to both liver-disease and healthy controls. Moreover, in IgG4-SC liver, RANKL-secreting cells specifically colocalized with cluster of differentiation 38-positive plasma cells and MDSCs, particularly monocytic MDSCs, and express the RANKL receptor in liver. Similarly, the frequency and number of peripheral blood MDSCs were significantly increased. Importantly, serum expression levels of RANKL were inversely correlated with the serum level of gamma-glutamyltransferase but significantly positively correlated with the frequency of MDSCs. Moreover, we confirmed that RANKL induced the expansion and activation of MDSCs through the RANKL/RANK/nuclear factor kappa B signal pathway. Of note, RANKL-treated MDSCs suppressed T-cell proliferation and induced Th2 differentiation. Conclusion: Our data suggest that plasma cell-derived RANKL induces the expansion and activation of MDSCs, which suppress T-cell proliferation and contribute to the Th2-type response characteristic of IgG4-SC.

Myeloid-derived suppressor cell accumulation in renal cell carcinoma is correlated with CCL2, IL-17 and IL-18 expression in blood and tumors.

Myeloid-derived suppressor cells (MDSC) play an important role in tumor-mediated immune evasion. Levels of MDSC in peripheral blood are increased in patients with cancer, correlating with cancer stage and outcome. Studies have confirmed the associations between MDSC and various cytokines in the peripheral blood of murine and human cancer hosts. However, little is known about the association between parenchymal MDSC subsets and cytokines, or the mechanism drawing MDSC into tumor parenchyma. The aim of this study was to analyze the correlation between MDSC subsets and tumor grade as well as stage in renal cell carcinoma (RCC) patients. The expression of chemokine (C-C motif) ligand 2 (CCL2), interleukin 17 (IL-17) and interleukin 18 (IL-18) in the peripheral blood and parenchyma of RCC patients was also detected to explore its correlation with MDSC accumulation. Total MDSC, granulocytic MDSC (G-MDSC), monocytic MDSC (M-MDSC), and immature MDSC (I-MDSC) from the blood and parenchyma were isolated and analyzed by flow cytometry. Cytokines were detected by the enzyme-linked immunosorbent assay (ELISA), real-time polymerase chain reaction (PCR) and western blot in blood and tumors. Parenchymal levels of MDSC had a positive correlation with levels of CCL2, IL-17, and IL-18, suggesting these cytokines may attract MDSC into the parenchyma. Moreover, peripheral total MDSC, G-MDSC and I-MDSC were shown to correlate with tumor grade and stage. Gene and protein expression of CCL2, IL-17, and IL-18 was significantly increased in blood and tumors of RCC patients. Our study has provided potential new targets for the risk stratification of patients with limited stages of renal carcinoma, in addition to elucidating a possible association between MDSC subsets and cytokine-induced migration into the tumor tissue.

Dynamics of CD25 Positive Myeloid Derived Suppressor Cells in Solid Organ Transplanted Patients and Relationship with Rejection

Backgound Myeloid derived suppressor cells (MDSC) are immature cells with immunosuppressive capacities. Three MDSC subsets are currently defined: monocytic, early stage, and polymorphonuclear MDSC (M-MDSC, eMDSC and PMN-MDSC respectively). While MDSC increase in cancer and chronic infections and associate with poor prognosis, their role in transplantation (Tx) is unknown. Changes in MDSC in transplant patients could provide biomarkers of graft evolution, and they could be useful as immunosuppressive therapy and/or to stimulate the allograft tolerance. Methods Peripheral blood MDSC were identified in cohorts of kidney (n=164) and liver (n=30) recipients and healthy volunteers (HV) as CD33+CD11b+HLA-DRlo/-. We characterized CD14+CD15- (M-MDSC) and CD14-CD15- (eMDSC) subsets. Suppression assays and measurement of surface CD25 expression (MFI) on MDSC were performed. Results Renal recipients MDSC were able to suppress CD4 and CD8 T cell proliferation in vitro. MDSC % were similar in pre-transplant, kidney transplant recipients (KTR), than in HV. However, MDSC and M-MDSC increased, mainly at 7 and 14 days post-transplant (3.48% and 3.85% vs 1.14%; 2.47% and 2.48% vs 0.24% p≤0,001 vs pre-transplant). The increase of MDSC in KTR with basiliximab as induction therapy was lower than in patients induced with thymoglobulin or without induction, and eMDSC were particularly decreased in basiliximab-treated patients (vs no induction, p≤0.05; vs thymoglobulin, p≤0.05). We confirmed that eMDSC expressed CD25, target of basiliximab. Pre-Tx, liver transplant recipients (LTR) had higher % of CD25+ eMDSC and higher CD25 MFI than KTR and HV. In LTR and KTR without basiliximab, % and MFI of CD25 in eMDSC increased after transplant. In KTR cohort, 7% of patients suffered acute rejection (AR). Absolute numbers of MDSC at 7 days post-transplant (measured before the rejection event) were significantly lower in AR than in non-rejectors (25.84 cells/uL vs 53.18 cells/uL respectively, p≤0,05). Conclusions MDSC and M-MDSC increase post-Tx except in patients receiving basiliximab. MDSC were lower in AR patients and low MDSC counts significantly preceded rejection. Transplant recipients eMDSC express CD25 which upregulates after Tx. Whether eMDSC express a complete and functional IL-2R is under investigation.

Clinical significance of changes of myeloid-derived suppressor cells and their subtypes in inflammatory bowel disease

Objective To explore the changes and their clinical significance of peripheral blood myeloid-derived suppressor cells (MDSC) and their subtypes in patients with inflammatory bowel disease (IBD). Methods From April 2016 to April 2017, 99 hospitalized IBD patients in 2nd Xiangya Hospital of Central South University were enrolled as observation group one, which included 84 Crohn′s disease (CD) (70 in active phase and 14 in remission phase) and 15 patients with ulcerative colitis(UC). At the same period, 32 healthy controls were enrolled as healthy control group one. The proportion of peripheral blood MDSC and subtypes of CD patients, UC patients and healthy controls were examined. Observation group two including 62 IBD patients (47 CD and 15 UC) were selected from observation group one and 21 healthy individuals were selected from healthy control group one as healthy control. The serum levels of tumor necrosis factor α (TNF-α) and interleukin 8 (IL-8) were detected. Chi square test, t test and one-way analysis of variance were performed for statistical analysis. Pearson correlation was performed for correlation analysis. Results The proportion of MDSC in peripheral blood mononuclear cells of CD and UC patients of observation group one were both higher than that of healthy control group one ((6.30±3.97)% and (7.50±3.12)% vs. (3.94±2.25)%, respectively), and the differences were statistically significant (t=-3.22 and -3.21, both P<0.01). The proportion of granulocytic MDSC in peripheral blood mononuclear cells of CD patients was higher than that of UC patients and healthy control group one ((65.69±20.45)% vs. (50.93±13.56)% and (51.50±11.61)%, respectively), and the differences were statistically significant (t=2.93 and 3.79, both P<0.01). The proportion of monocytic MDSC in peripheral blood mononuclear cells of UC patients was higher than that of CD patients and healthy control group one ((28.41±18.33)% vs. (18.38±17.43)% and (28.17±10.22)%, respectively), and the differences were statistically significant (t=2.22 and 2.93, both P<0.05). The proportion of granulocytic MDSC was higher and the proportion of monocytic MDSC was lower in peripheral blood mononuclear cells of CD patients in active phase than those of CD patients in remission phase ((67.36±2.27)% vs. (46.49±6.32)%, and (17.19±2.02)% vs. (34.33±6.12)%), and the differences were statistically significant (t=3.60 and 3.26, both P<0.01). The serum level of TNF-α of CD patients of observation group two was higher than that of UC patients and healthy control group two ((7.83±6.54) ng/L vs. (4.77±2.12) ng/L and (4.40±2.05) ng/L), and the differences were statistically significant (t=2.01 and 2.53, both P<0.05). The serum level of IL-8 of UC patients of observation group two was higher than that of CD patients and healthy control group two ((65.80±45.14) ng/L vs. (25.80±22.32) ng/L and (26.40±22.37) ng/L), and the differences were statistically significant (t=4.87 and 4.21, both P<0.01). Granulocytic MDSC was positively correlated with TNF-α (r=0.319, P=0.011) and was negatively correlated with IL-8 (r=-0.296, P=0.019). Monocytic MDSC was negatively correlated with TNF-α (r=-0.260, P=0.040) and was positively correlated with IL-8 (r=0.306, P=0.016). Conclusions The proportion of granulocytic MDSC in peripheral blood mononuclear cells significantly increases in active CD patients, while the proportion of monocytic MDSC significantly increases in UC and CD patients in remission phase. Detection of MDSC and their subtypes maybe helpful in the differentiation of CD and UC as well as the diagnosis and treatment of CD. Key words: Inflammatory bowel diseases; Tumor necrosis factor α; Interleukin 8; Myeloid-derived suppressor cells and subsets

IL-17 inhibits the accumulation of myeloid-derived suppressor cells in breast cancer via activating STAT3

Breast cancer (BC) is one of the most common cancers, with high recurrence rate and poor prognosis of recurrent metastatic disease. In our study, we analyzed the markers and development of markers of myeloid-derived suppressor cells (MDSCs) for BC progression and occurrence. MDSCs is one of the major orchestrators of the immunosuppressive network, are associated with immune suppression and considered a prime target for cancer immunotherapy. Interleukin-17 (IL-17) is a signature cytokine of Th17 cells. Previous research has indicated that IL-17 plays a proinflammatory role. It was found to increase frequencies at certain tumors and involved in angiogenesis. This study aims to elucidate the biological role of IL-17 on MDSC in BC cells.Expression of MDSC in peripheral blood of 80 BCE patients and 20 healthy volunteers was compared. Our results indicate that MDSC numbers in patients with BC were higher than healthy donors. Moreover, the clinical grade and prognosis were correlate with the number of MDSC. In this study, we investigated the effect of IL-17 on MDSCs. CCK-8 assay and flow cytometry were used to assess the proliferation and apoptosis of cells. The expression of key MDSC-related molecules was detected by western blotting. We identified administration with IL-17 in vitro significantly induced MDSC differentiation, inhibited their proliferation and triggered apoptosis. In addition, Low IL-17 inhibited the activation of STAT3, leading to increase formation of MDSCs in BC. Our results from experiments suggest that the effects of IL-17 mediate activation of STAT3 signaling in BC cells. Taken together, our study shows that MDSCs can be a new type prognostic marker in BC patient. Targeting IL-17/Stat3 signaling may be a promising strategy for BC treatment.

High numbers of myeloid derived suppressor cells in peripheral blood and ascitic fluid of cirrhotic and HCC patients

ABSTRACTBackground: Hepatocellular carcinoma (HCC) is the 3rd most common cause of cancer-related death worldwide. It has evolved different immune escape mechanisms, which might include emergence of lymphoid and myeloid regulatory cells.Aim of this work: To determine the numbers of Myeloid-derived suppressor cells (MDSCs) in peripheral blood and ascitic fluid in cirrhosis and HCC and their relation to IFN-γ and α-fetoprotein (α-FP).Patients and methods: Sixty individuals were enrolled in this study; forty cirrhotic patients with ascites; twenty without HCC (Group I), and twenty with HCC (group II) as well as twenty healthy individuals as a control group (group III). The phenotype and numbers of MDSCs were analyzed in peripheral blood of all the individuals and ascitic fluid of the patients using flow cytometry. Intracellular IFN-γ and serum alfa-fetoprotein were measured.Results: Significant increases in the relative and the mean number of peripheral blood MDSCs were found in the cirrhosis and HCC groups than in the control group, with the HCC group showing the highest number. MDSC count was negatively correlated with IFN-γ levels, while α-FP was positively correlated with MDSC% in the HCC group. MDSC count was low in ascitic fluid of both HCC and cirrhosis groups with no significant difference between the 2 groups.Conclusion: A high frequency of MDSCs was detected in the peripheral blood of cirrhotic and HCC patients, indicating presence of immunosuppressive arms. These cells could be targeted to develop a new effective immunotherapy or an adjuvant to current therapies.

High granulocytic myeloid-derived suppressor cell levels in the peripheral blood predict a better IVF treatment outcome

Objective Myeloid-derived suppressor cells (MDSCs) have been described as important immunosuppressive cells for maternal immune tolerance. The aim of this study was to detect whether there was any association between the peripheral blood MDSCs level and in vitro fertilization (IVF) treatment outcomes. Methods This prospective observational study randomly recruited 85 women who underwent IVF treatment from May 2016 to June 2016. The levels of peripheral blood granulocytic MDSC (G-MDSC), monocytic MDSC (M-MDSC) and their relations to IVF treatment outcomes were analyzed. Results The circulating G-MDSC level was significantly increased in the clinical pregnant group when compared to that in the nonclinical pregnant group (p = .014), while M-MDSC had no significant difference. The G-MDSC level was an independent predictive factor for clinical pregnancy with odds ratios 12.7 (95% CI: 1.53–105.4, p = .018) when using multiple logistic regression analysis. A receiver operating characteristic analysis (area under curve = 0.634) found the clinical pregnancy rate in women with G-MDSC >2.38% was higher than that in women below this level (96 versus 66.7%, p = .004). The high G-MDSC level in the peripheral blood was associated with clinical pregnancy, with a sensitivity of 37.5%, specificity of 95.2%. Conclusion High circulating G-MDSC level was associated with elevated clinical pregnancy rate. G-MDSC might be a new therapeutic target for better IVF treatment outcome.

Inhibition of Inflammatory Cytokines and Induction of Myeloid-Derived Suppressor Cells by the Effects of Granulocyte and Monocyte Adsorption Apheresis.

Pro-inflammatory cytokines are involved in the pathogenesis of inflammatory skin diseases attributable to activated neutrophils and macrophages. Myeloid-derived suppressor cells (MDSCs) play an important role in the regulation of the immune response and possess strong immunosuppressive and anti-inflammatory properties. Granulocyte and monocyte adsorption apheresis (GMA), an extracorporeal apheresis instrument featuring columns containing cellulose acetate (CA) beads, is designed to remove pathogenic myeloid lineage cells. The purpose of this study was to investigate the effects of GMA on cytokine production and MDSC induction. The serum level of various inflammatory cytokines and the incidence of MDSCs in peripheral blood before and after GMA treatment were recorded. Cytokines were assayed with the suspension-array method in 38 patients. The incidence of MDSCs was analyzed by FACS in eight patients and the effect of GMA on in vitro MDSC induction was examined using a mini-column system that mimics GMA. The serum level of IL-2Rα (P = 0.030), IL-8 (P = 0.018), and MIF (P = 0.0002) was significantly decreased by GMA and the incidence of MDSCs was increased (P = 0.030). With the mini-column system, MDSCs were induced in the peripheral blood of five healthy volunteers; the in vitro induction was significantly inhibited by inactivation of the complement component iC3b. The clinical effectiveness of GMA may be attributable to the inhibition of pro-inflammatory cytokines and the induction of anti-inflammatory MDSCs by iC3b activation via the CA beads in the GMA column.