Expression Of MDSC In DLBCL And Mechanism Of Promoting SLE Disease Through INOS

BackgroundNormally,hematopoietic stem cells(HSCs)differentiate into myeloid progenitor cells in bone marrow,which produce immature myeloid cells(IMCs)with no inhibitory function in an inactivated state.IMCs differentiate into mature and functional dendritic cells(DCs),macrophages and granulocytes.However,the differentiation of IMCs is blocked in some pathological conditions,such as inflammation,tumor,infection,sepsis and autoimmune diseases.IMCs is activated and proliferated to differentiate into myeloid-derived suppressor cells(MDSC).MDSC is a newly discovered immature myeloid cell,which inhibit host immune function in tumors,infections and inflammatory diseases.In recent years,increasing studies have shown that MDSC plays a key role in regulating host immune function in various types of tumors and autoimmune diseases.MDSC inhibit host immune response through a variety of different mechanisms,including direct cell-cell contact and secretion of a variety of inhibitory soluble mediators,of which the most important factors are arginase-1(Arg-1)and inducible nitric oxide synthase(i NOS).Therefore,exploring the mechanism of MDSC in the development of diseases may help to regulate the inhibitory effect of MDSC on host immune system,which provide new ideas and strategies for immunotherapy of many diseases.Part I: Expression of M-MDSC in DLBCLDiffuse large B-cell lymphoma(DLBCL)is the most common pathological subtype of adult non-Hodgkin's lymphoma(NHL),accounting for about 30%-40% of non-Hodgkin's lymphoma.DLBCL is a group of lymphoma with heterogeneity in pathomorphology,clinical manifestation and prognosis.Although great progress has been made in the treatment of DLBCL after the clinical promotion of rituximab,more than half of the patients eventually relapse,and the prognosis of recurrent DLBCL patients is very poor.Therefore,it is particularly important to carry out risk staging,evaluate adverse prognostic factors,screen out high-risk patients and choose individualized treatment after the diagnosis of DLBCL.Therefore,in order to find indicators that can predict the poor prognosis of patients,in-depth study of the pathogenesis of DLBCL has important medical value.ObjectiveThe aim of this study is to detect the expression of MDSC in peripheral blood and lymph nodes of patients with DLBCL,as well as analyze the relationship with the occurrence,stage,treatment effect and prognosis of the disease.MethodsA total of 103 DLBCL patients treated in the Department of Hematology of the second affiliated Hospital of Anhui Medical University and the 105 th Hospital of Chinese PLA from March 2015 to January 2019 were selected as the experimental group.All patients were diagnosed and treated in accordance with American NCCN guidelines.There were 65 cases of newly diagnosed patients,12 cases of recurrent patients and 26 cases of remission patients.Among the 65 patients with newly diagnosed DLBCL,there were 40 males and 25 females,aged from 28 to 80 years old,with a median age of 58.7 years.According to NCCN staging,there were 15 cases of stage ?,22 cases of stage ?,16 cases of stage ? and 12 cases of stage ?.12 patients with reactive lymph nodes were selected as the control group.In this study,we used CD14+HLA-DR-/low as the immunophenotype of MDSC to explore the difference between DLBCL patients and control groups in peripheral blood and lymph nodes,as well as analyze the correlation with clinical data,such as staging,grouping and prognosis of DLBCL patients.Secondly,to analyze the changes of MDSC level in newly diagnosed DLBCL patients before and after chemotherapy,which may provide a basis for clinical judgment of prognosis and clinical efficacy.Further experiments in tumor-bearing mice were carried out to verify the role of MDSC in the occurrence and progression of tumor model in DLBCL mice.Results1.The expression of MDSC in patients with newly diagnosed DLBCL was significantly higher than that of patients with reactive lymph node hyperplasia.2.The expression of MDSC and TAM in lymph nodes of patients with newly diagnosed DLBCL were significantly higher than those of patients with reactive lymph node hyperplasia.3.The expression of MDSC in patients with advanced stage(stage ?-?)DLBCL was significantly higher than that of patients with early stage(? + ?).4.The level of MDSC in DLBCL patients with elevated lactate dehydrogenase(LDH)was significantly higher than that of patients with normal LDH level.5.The level of MDSC in DLBCL patients with high IPI score was significantly higher than that of patients with low IPI score.6.After treatment,the level of MDSC in patients with newly diagnosed DLBCL significantly decreased.7.There was no significant correlation between the level of MDSC in peripheral blood and age,sex and the presence of B symptoms in patients with newly diagnosed DLBCL.8.In newly diagnosed DLBCL patients,MDSC was positively correlated with IPI score and negatively correlated with OS.9.The levels of GM-CSF,IL-6 and IL-35 in newly diagnosed DLBCL patients were significantly increased,which induced the amplification and aggregation of MDSC in host circulation and tumor microenvironment.10.The levels of Arg-1 and i NOS in newly diagnosed DLBCL patients were increased.It is suggested that MDSC may play an immunosuppressive role through Arg-1 and i NOS in patients with newly diagnosed DLBCL.11.The experiment of tumor-bearing mice further showed that the expression levels of total MDSC,G-MDSC and M-MDSC in tumor-bearing mice were abnormally higher than those of wild-type mice.After treatment with doxorubicin,the expression levels of total MDSC,G-MDSC and M-MDSC significantly decreased.Conclusion In this study,it was found that there was a severe immune dysfunction in patients with DLBCL.The expression of MDSC is significantly increased and is closely related to the occurrence and development of the disease,which can be used as a prognostic factor for patients with newly diagnosed DLBCL.Down-regulation of the expression and function of MDSC may help to improve the anti-tumor immune function of the host.In summary,MDSC plays an important role in the occurrence and development of DLBCL,which provides a new scientific research idea for further exploring the pathogenesis of DLBCL.Part II: Mechanism of M-MDSC promoting SLE disease through i NOS Systemic lupus erythematosus(SLE)is a common clinical autoimmune disease characterized by multi-organ and multi-system damage.The current incidence of SLE is 0.31-0.70 ‰ in China.SLE has a long course,repeated postponement,high disability rate and great harm to human tissue.At present,there is no completely effective method for the treatment of SLE,which can only be relieved clinically and cannot be cured.The pathogenesis of SLE is complex,which is caused by genetic,environmental,immune and other factors,in which abnormal autoimmune tolerance plays an important role.Abnormal immune effector cells and regulatory cells breaks the balance of autoimmune tolerance.Among all kinds of immune cells,MDSC is a key factor to regulate immune homeostasis.However,the specific mechanism of MDSC in the pathogenesis of SLE remains to be further studied.Therefore,to explore the role of MDSC in the pathogenesis of autoimmune diseases may be a more accurate target for the treatment of SLE.ObjectiveThe aim of this study is to determine the expression and immunosuppression mechanism of MDSC in patients with SLE.Further understand the mechanism of occurrence and development of SLE will explore new potential therapeutic targets.Methods32 newly diagnosed SLE patients treated in the second affiliated Hospital of Anhui Medical University from May 2018 to Febreary 2020 were selected as the experimental group.30 healthy adults matched with age and sex were selected as the control group.In this study,we used CD14+HLA-DR-/low as the immunophenotype of MDSC to explore the difference in the level of peripheral blood between SLE patients and control groups.In vitro,further investigation was made to explore the specific mechanism of MDSC in the pathogenesis of SLE.Results 1.T cell proliferation inhibition test showed that CD14+HLA-DR-/low cells patients with SLE had immunosuppressive effect and could be identified as MDSC.2.The expression of MDSC in newly diagnosed SLE patients was significantly higher than that of the control group.3.The level of MDSC in newly diagnosed SLE patients was closely related to sex,lupus nephritis and disease activity,and positively correlated with SLEDAI score.4.The levels of GM-CSF,IL-6 and i NOS in patients with newly diagnosed SLE were significantly increased.However,the level of Arg-1 was not significantly increased.5.Induction test showed that the peripheral plasma of newly diagnosed SLE patients could induce the production of MDSC from normal human PBMC.6.In vitro,experiments further showed that MDSC mainly produced immunosuppressive effect through i NOS on patients with SLE.Conclusion In SLE patients,host immune function is performancing a state of disorder.The level of MDSC in newly diagnosed SLE patients was significantly higher than that of healthy controls,which was positively correlated with disease activity.After treatment,the level of MDSC decreased,suggesting that MDSC can be used as one of the indicators to judge the effect of treatment.In addition,there are high concentrations of GM-CSF and IL-6 in the peripheral blood of patients with SLE which induce abnormal amplification of MDSC and play an immunosuppressive role in an i NOS-dependent manner.Therefore,the highly expressed MDSC still has immunosuppressive effect,and mediates the abnormal immune tolerance of SLE by secreting i NOS.However,it is not enough to inhibit the abnormal immune function of SLE,so as to promoting the occurrence and development of SLE.