| The sepsis,a heterogeneous syndrome characterized by organ dysfunction caused by a dysregulated host response to infection,has continued to be one of the leading causes of death in intensive care units in developed countries.Accumulating evidence indicates that the sepsis is a pathological syndrome,characterized by persistent excessive inflammation and immunosuppression due to the inability of the immune response to restore homeostasis due to the invasion of pathogens.In addition,the abnormal host immune response and"cytokine storm" triggered by inflammatory factors can lead to Systemic Inflammatory Response Syndrome(SIRS),Septic Shock,Multiple Organ Dysfunction Syndrome(MODS),and even the death of the patient.The current understanding of the pathogenesis of sepsis includes:complex inflammatory network effects,immune dysfunction,gene polymorphisms,tissue and organ damage,etc.Different pathogenic microorganisms and their toxins lead to abnormal reactions in the body.The pathogenesis of sepsis is closely related to the pathophysiological changes of multiple organs in the body.With the deepening of understanding,we need to translate these understandings into new targeted therapeutic strategies.The key to the clinical development of new treatments for sepsis is to select patients based on biomarkers and functional deficits that can provide specific mechanisms for the expression or activity of therapeutic targets.The co-suppressor B7-H4,also known as B7S1 and VTCN1,is the seventh member of the B7 family discovered in 2003.It is an inhibitory immune checkpoint with important implications for human disease.The tissue-expressed B7-H4 minimizes autoimmune and inflammatory responses.The B7-H4 is an important member of the B7 family and is abnormally expressed in tumors,inflammatory and some autoimmune diseases.The B7-H4 negatively regulates T cell immune responses and promotes immune escape by inhibiting T cell proliferation,cytokine secretion,and cell cycle.The B7-H4 has two functional isoforms,namely soluble(sB7-H4)and membranebound(mB7-H4).It has been shown that the soluble B7-H4 is decomposed from cell membrane B7-H4 in the inflammatory factor microenvironment,and can reach the whole body with body fluids,playing an important role in inflammatory diseases.what’s more,it has become an interesting biomarker of detection value in the pathological process of immune inflammation.In this paper,by analyzing the biological factors regulated by the immune validation of sepsis,and taking the role and clinical significance of the two subtypes of B7-H4 in immune inflammation as the main line,the following researches were carried out:Study on the clinical value of soluble B7-H4 detection in patients with sepsisObjectives Sepsis is one of the common clinical emergencies,often in critical conditions,with high mortality.At present,there are still a lot questions to answer,such as difficult diagnosis and poor treatment effect.The sepsis immune inflammation involves immune dysfunction,T cell dysfunction or apoptosis,and cytokine secretion dysregulation.Immunotherapy,which intervenes from the aspects of immune inflammation regulation and immune cell activation,has always been focused by researchers.B7-H4 is one of the costimulatory molecules of the B7 family.There is evidence that B7-H4 has negative regulatory effects such as inhibiting T cell function and cytokine secretion,but the role of B7-H4 in sepsis immune inflammation is unclear.Therefore,in this part of the study,we apply the expression characteristics of soluble B7-H4(sB7-H4)which were detected in the peripheral blood of sepsis patients and healthy people,combined with clinical data,to analyze the diagnostic and prognostic value of sB7-H4 in sepsis.The goal of this study is to explore the feasibility of B7-H4 in sepsis immunotherapy,and to provide basis for clinical diagnosis and treatment.Methods(1)Sepsis patients and healthy people who met the inclusion criteria were enrolled;(2)General data of sepsis patients and healthy people were collected;(3)Peripheral blood was collected from the research subjects,and the expression levels of sB7-H4,sPDL1,sCD40L,IL-6 and sCD25 in peripheral blood serum were determined by enzyme-linked immunosorbent assay(ELISA).Results(1)The sB7-H4 molecule was highly expressed in the peripheral blood of sepsis.(2)The sB7-H4 can be used as a biological marker of sepsis,with auxiliary diagnostic value.(3)It was grouped according to the source of infection,and there were differences in some clinical indicators between groups.The expression of sB7-H4 in sepsis of various sources of infection was lower in the pneumonia group and higher in the biliary tract infection group.(4)According to the APACHEII score,there was no difference in the expression of sB7-H4 between the severe group and the non-severe group.The high expression of sB7-H4 molecule was positively correlated with the severity of sepsis.But there is no statistical difference.(5)The high expression of sB7-H4 molecule was related to the prognosis of sepsis.(6)In the peripheral blood of sepsis,the inflammatory factors sPDL1,sCD25 and IL-6 are highly expressed,and the inflammatory factor sCD40L was lowly expressed.The expression of sB7-H4 molecule was to the inflammatory factors.At D0,sB7H4 was positively correlated with sPD-L1 and sCD25.At D2,sB7-H4 showed the same result with sPD-L1 and sCD25,while negatively did with CD40L.At D7,sB7-H4 was positively correlated with sPD-L1 expression.Conclusion(1)The expression of sB7-H4 in peripheral blood of patients with sepsis is increased.In the sepsis of different etiologies,the expression of biliary tract infection is the most obvious,and it makes the lowest in pulmonary infection.The sB7-H4 can be used as a biomarker for auxiliary diagnosis of sepsis,and the combined index based on sB7-H4 has higher diagnostic value.(2)In sepsis the sB7-H4 is positively related to the severity of sepsis.In addition,the sB7-H4 is related to sepsis mortality,and the expression of sB7-H4 has the predictive prognostic value in different stages of sepsis.(3)In the early stage of sepsis,the initiation of pro-inflammatory molecules and T cell immune responses is accompanied by the simultaneous activation of anti-inflammatory molecules.(4)The B7-H4 is expected to regulate the immune response and improve the prognosis of sepsis by precisely intervening B7-H4 in different immune states.The expression of CD14+cell membrane molecule B7-H4 in sepsis and its regulatory factorsObjectives After infection,immune cell activation,cytokine activation,cytokine drift,etc.occur in the body,resulting in uncontrolled inflammatory response,immune disorder,and organ function damage.T-cell immune response is a key link in the immune response of sepsis.Costimulatory molecules are divided into the positive and the negative,which transmit the second signal in the T-cell immune response and control the time and extent of the inflammatory response.The costimulatory molecule B7-H4 plays a negative regulatory role in the immune response by controlling the cell cycle,inhibiting the proliferation and differentiation of T cells,and inhibiting the secretion of cytokines.However,it is unknown whether B7-H4 is a key molecule of the immune response to sepsis,and whether sepsis regulates the immune response by regulating the expression of B7-H4,that still remains uncertain.Costimulatory molecules are mostly expressed on antigen-presenting cells(APCs).Based on the high expression of sB7-H4 in peripheral blood in sepsis,it is speculated that the expression of monocyte membrane B7-H4(mB7-H4)is also abnormal.Therefore it is necessary to clarify the membrane expression and the influence of representative cytokines of sepsis on the expression of mB7-H4,so as to provide a basis for further verification that B7-H4 plays an important regulatory role in the immune response of sepsis.Methods(1)The sepsis patients and healthy people who met the inclusion criteria were enrolled.(2)General data of the sepsis patients and healthy people were collected.(3)Peripheral blood was collected from the research subjects,and the expression characteristics of mB7-H4 in peripheral blood CD14+cells were detected by flow cytometry(FCM).(4)PBMCs from the healthy human blood were isolated and stimulated with the patient blood,healthy human blood,LPS,IFN-γ,TNF-α,and IL-10.The expression difference of mB7-H4 in peripheral blood CD 14+cells was detected by flow cytometry(FCM).Results(1)The expression of mB7-H4 in CD 14+cells of sepsis patients was lower than that of healthy people.(2)With stimulation by the LPS,IFN-γ,TNF-α and patient blood,the expression of mB7-H4 in CD 14+cells was lower than that in blank control group and negative control group.While with stimulation by the IL-10,the expression of mB7-H4 in CD 14+cells was higher than that in those groups.Conclusion(1)The inflammatory response of sepsis has a down-regulation effect on the expression of B7-H4 membrane,and mB7-H4 is involved in the immune response of sepsis.(2)INF-γ and TNF-α can down-regulate the expression of mB7-H4 on CD14+ cells,but IL-10 can up-regulate.The mB7-H4 is regulated by sepsis-important cytokines.Experimental study on the regulation of T cell function and lung tissue protection by B7-H4 in sepsisObjectives The occurrence of sepsis is related to the inability of T cells,and the further development of sepsis leads to an imbalance of immune function,which is manifested as immune overstimulation or immune paralysis,including T cell apoptosis,cytokine imbalance,etc.,and eventually develops into the organ function damage.In T cell immune responses,the costimulatory signals are necessary for maintaining T cell function.As a negative co-stimulatory molecule,B7-H4 transmits inhibitory signals,and it has been proved to have a negative regulatory effect in the study of oncology.In the above studies,we found that sepsis and sepsis-related inflammatory factors also affect the expression of B7-H4.However,whether the intervention of B7-H4 can regulate the immune response of sepsis,the secretion of cytokines,or it has an effect on organ damage which still needs further verification.Therefore,in this part of the study,we constructed the co-culture environment of T cells and CHO cells overexpressing B7-H4 from the cellular level,meanwhile,did the mouse LPS sepsis model from the animal level,to explore the regulation of B7-H4 on sepsis immune inflammation,eventually to provide a basis for clinical search for potential immunotherapy methods for sepsis.Methods(1)B7-H4 overexpressing CHO cells and T cells were co-cultured,and detected by CCK-8 method T cell proliferation.(2)ELISA was used to detect the differences in cytokine secretion by T cells in the supernatant of the co-culture system.(3)LPS poisoning model was established in mice.(4)ELISA was used to detect serum IL-1β,IL-6 and TNF-α expression.(5)Pathomorphological analysis of the lung tissue of LPS poisoning model mice by paraffin embedding and HE staining.Results(1)The results of in vitro co-culture experiments show that CHO cells overexpressing B7-H4 can significantly inhibit the proliferation of T cells.(2)B7-H4 inhibited the production of IFN-γ and IL-2.(3)B7-H4 knockout enhanced inflammation in LPS model mice.(4)Compared with the wild model group,the lung tissue damage in the B7-H4 knockout model group was more severe,manifested by more neutrophil infiltration.Conclusion(1)Overexpression of B7-H4 inhibits T cell proliferation and cytokine production,while B7-H4 deficiency promotes cytokine expression.B7-H4 can regulate the immune response of sepsis by inhibiting T cell proliferation and cytokine secretion.(2)B7H4 deficiency aggravates lung injury in mice with sepsis,and B7-H4 has a protective effect on lung injury. |
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