Study On The Correlation And Mechanism Of Infection And ITP

The First Part etrospective Evaluation of The Relationship Between Infection and Primary Immune ThrombosisIntroduction:Primary immune thrombocytopenia((primary immune thrombocytopenia,ITP)is a complex autoimmune disease characterized by decreased platelet count and increased risk of bleeding.As the most common clinical hemorrhagic disease,ITP accounts for about 1/3 of adult clinical hemorrhagic diseases.The annual incidence rate of ITP in the world is 3.2 million per year.The latest epidemiological data show that except for women of childbearing age,the incidence rates of men and women are equal.The main clinical manifestations are bleeding spots or ecchymosis in the skin or mucosa caused by thrombocytopenia,and even bleeding in the brain and other important organs.Glucocorticoid is a classic first-line treatment strategy.Recent studies have found that high-dose dexamethasone can be used as the preferred corticosteroid in the first-line treatment strategy of adult ITP.Failure of first-line treatment can be treated with second-line drugs(such as thrombopoietic drugs,rituximab,etc.)or splenectomy.At present,it is believed that ITP is mainly characterized by increased platelet destruction and/or thrombocytopenia,platelet destruction mediated by antigen-specific autoantibodies and/or direct lysis of platelets by cytotoxic T cells are important reasons for the increase in platelet destruction,while autoimmune-mediated megakaryocyte maturation and apoptosis abnormalities will lead to thrombocytopenia in patients with ITP.Thrombocytopenia is a common symptom in patients with viral and bacterial infection,while infection is a common clinical complication in patients with chronic ITP,and it may also be an inducing factor of ITP.The morbidity and mortality are high,which is mainly caused by corticosteroids and other immunosuppressants.The latest research shows that ITP infection is not only related to immunomodulatory therapy,but also to the disease itself.ITP thrombocytopenia can cause immune decline and increase the risk of infection in patients.At present,there are few studies on infection in patients with ITP,the correlation between infection and ITP and its mechanism are not clear,and there is a lack of detailed clinical data to analyze the risk of infection.In order to further study the relationship between infection and ITP,explain clinical phenomena and guide clinical work,we conducted a case retrospective study.Research objective:1.To analyze whether infection will aggravate the decrease of platelet count in patients with ITP.2.To evaluate the correlation between thrombocytopenia and infection in patients with ITP,and to clarify the role of platelet count in the risk of infection.3.To further explore the effect of infection on platelet count in patients with ITP.Method:We selected data from the cohort of ITP patients in a prospective multicenter randomized clinical trial by Wei et al.,and retrospectively analyzed the relevant data of 158 patients.The study was divided into infected and non-infected ITP patients.1.The sex,age,autoantibody expression,treatment type and blood cell count of the two groups of ITP patients were statistically analyzed.2.The platelet counts of the two groups of patients with ITP at different time points were statistically analyzed.3.The response rate of hormone therapy and hospitalization time of the two groups of ITP patients were statistically analyzed.4.The responsiveness of two groups of ITP patients to platelet transfusion was analyzed.5.For ITP patients in infection group,platelet count was used as a risk factor for infection,and the correlation between platelet count and infection was analyzed.Results:1.In the first month after grouping treatment,38 patients had bacterial or viral infection,with an infection rate of 24%.There was no significant difference in age,sex,autoantibody,blood routine test and type of hormone therapy between infected and non-infected ITP patients.2.There was no significant difference in platelet count between infected and non-infected ITP patients(11.8 ± 10.4 × 109/L VS 13.8 ± 12.8 × 109,P>0.05).The platelet count of infected ITP patients was significantly lower than that of non-infected ITP patients on the 28th day,and there was no significant difference between the two groups on the 21th day(P>0.05).The results showed that there was no significant difference in the platelet count between the infected and non-infected ITP patients at the 28th day,and at the 21th day,the platelet count of the infected and non-infected patients was significantly lower than that of the non-infected patients(P<0.01).3.The response rate of ITP infected patients to hormone therapy was significantly lower than that of non-infected ITP patients.The hospitalization time of patients with ITP infection was significantly longer than that of non-infection patients.4.There was a significant correlation between platelet count and infection in patients with ITP,and the correlation coefficient of Spearman was-0.517(P<0.01);the correlation coefficient of Pearson was-0.447(P<0.01).For patients with ITP infection,platelet count was a risk factor for infection,with a risk ratio of 0.52(HR 0.52,95%CI 0.35-0.77,P=0.001).5.91 patients(58%)were given one or more platelet transfusions in the first month of treatment.Platelet transfusion can slightly increase platelet count in non-infected patients with ITP,but there is no significant change in platelet count in patients with infected ITP after platelet transfusionConclusions:To sum up,infection is a common clinical complication in patients with primary immune thrombocytopenia.Can lead to primary immune thrombocytopenia patients with reduced response to hormone therapy,longer hospital stay,and low platelet count also increases the risk of infection.Significance:Infection is a common clinical complication of primary immune thrombocytopenia,which can lead to poor response to various treatments and prolonged hospitalization.Through the preliminary study of the relationship between low platelet count and infection,we need to further study the mechanism of low platelet count in infected ITP and the timing of platelet transfusion treatment,so as to provide theoretical basis for solving clinical problems.The Second Part stablishment of A Mouse Model For The Study of The Relationship Between Infection and ITP and Its Mechanism.Introduction:Infection refers to the local tissue and systemic inflammatory reaction caused by bacteria,viruses,fungi or parasites.Bacterial infection is a common form of clinical infection,which is divided into gram-positive bacteria and gram-negative bacteria.Colorectal bacilli is the most common gram-negative pathogenic bacteria in clinic.Lipopolysaccharide(LPS),also known as bacterial endotoxin,is the most toxic component of Gram-negative bacteria.It forms the outer membrane of Gram-negative bacteria together with protein and phospholipids.Long-term studies have confirmed that Gram-negative bacteria participate in pathological processes such as sepsis,septic shock and multiple organ failure through lipopolysaccharide.Gram-negative bacteria infection can aggravate the consumption and destruction of platelets and significantly reduce platelet count,and the degree of infection is related to the degree of thrombocytopenia.Chen et al have demonstrated that bacterial lipopolysaccharide is a very effective activator of mononuclear macrophages,and the release of this endotoxin may enhance or further magnify the phagocytosis of cells from patients with autoimmune diseasesIn recent years,studies on platelets have found that platelets not only play a core role in hemostasis,but also interact directly with white blood cells and endothelial cells,and assist and regulate inflammatory and immune responses by releasing soluble inflammatory mediators.these inflammatory mediators can promote the recruitment of white blood cells and trigger their activation.In the study of ITP,it was also found that platelets have immunomodulatory and protective effects and participate in the interaction between pathogens and host defense systems.There are a large number of receptor molecules on the surface of platelets,which enable platelets to quickly sense invading pathogens and inflammation caused by infection,which is the alarm of the body.Recent studies have found that platelets can reduce the increase of plasma pro-inflammatory factors caused by infection,inhibit macrophage-dependent inflammation,and thus inhibit the occurrence and development of septic shock.Primary immune thrombocytopenia(ITP)is an immune-mediated hemorrhagic disease with increased platelet destruction and decreased production.Its main clinical manifestation is thrombocytopenia.Infection is a common complication in clinical treatment of ITP patients.Previous studies found that ITP patients were mainly bacterial infection,and platelet count was negatively correlated with infection time,treatment effect and hospital stay.However,the relationship and mechanism between them are not clear,so whether bacterial infection caused by acupuncture is a risk factor for aggravating ITP,we studied the effect of lipopolysaccharide on ITP mouse model and its related mechanism.Research objective:1.A stable ITP mouse model was established,and the bacterial infection model of ITP mice was simulated by intraperitoneal injection or tail vein injection of bacterial endotoxin lipopolysaccharide(LPS).The platelet count was detected to study whether LPS infection could aggravate the decrease of platelet count in ITP mice.2.To explore the effect and mechanism of elevated bacterial endotoxin lipopolysaccharide(LPS)on ITP mouse model.The proportion of Treg cells in thymus and spleen cells of LPS infected mice was detected by flow cytometry to study the effect of Treg cells on LPS aggravating thrombocytopenia in ITP mice.3.The proportion of monocytes,neutrophils and M1 cells in spleen cell suspension of LPS infected ITP mice was detected by flow cytometry,and the adhesion ratio of platelets in peripheral blood of LPS infected ITP mice to monocytes,neutrophils and M1 cells was detected to explore the mechanism of LPS aggravating thrombocytopenia in ITP mice.4.To explore the role of bacterial endotoxin lipopolysaccharide(LPS)in ITP,explain clinical phenomena and provide possible treatment direction.Method:1.The passive model of ITP mice was established.Mice were injected intraperitoneally with CD41 antibody(MWReg30)to detect platelet count.2.The mouse model of lipopolysaccharide(LPS)infection with ITP was established.The platelet count of ITP mice infected with ITP was detected by intraperitoneal injection or tail vein injection of E.coli endotoxin LPS.3.The ITP mice infected with LPS were killed after the peripheral blood was collected,and the spleen was dissected and weighed for morphological comparison.4.The single cell suspensions of thymus and spleen of mice infected with LPS and ITP were made,and the proportion of Treg cells in thymocytes was detected by flow cytometry.5.The spleen monocyte suspension of mice infected with LPS and ITP was made,and the proportion of spleen mononuclear cells,neutrophils and macrophages M1 cells was detected by flow cytometry.6.The peripheral blood of ITP infected mice was collected 4 hours after LPS infection,and the adhesion ratio of peripheral blood platelets to monocytes,neutrophils and macrophages M1 cells was detected by flow cytometry.Results:1.The stable ITP mouse model and LPS infected ITP mouse model were established successfully.2.LPS infection can significantly reduce the platelet count of ITP mice.The difference of platelet count in Day0,Dayl,Day3 and Day5 among the four groups was compared,the results showed that there was no significant difference in platelet count among the four groups at Day0(P>0.05),but at Dayl,Day3 and Day5,the platelet count of LPS infected ITP mice was significantly lower than that of non-infected ITP group,LPS group and blank control group(P<0.05).3.LPS infection can stimulate spleen enlargement in ITP mice.The spleen volume and weight of ITP mice infected with LPS were significantly larger than those of ITP group and control group(P<0.05).4.LPS infection can affect CD4+CD25hiFoxp3+Treg cells in thymus and spleen of ITP mice.The proportion of CD4+CD25hiFoxp3+Treg cells in LPS infected ITP mice was significantly lower than that in ITP group,LPS group and control group(P<0.05).5.There was no significant difference in the proportion of spleen monocytes between LPS infected ITP mice and ITP and LPS groups(P>0.05).The proportion of platelet adhesion to monocytes in ITP mice infected with LPS was significantly lower than that in ITP group(P<0.05).6.The percentage of neutrophils in spleen of ITP mice infected with LPS was significantly different from that of ITP and LPS groups.The proportion of platelet adhesion to neutrophils in ITP mice infected with LPS was significantly lower than that in ITP group.7.he proportion of spleen M1 cells in LPS infected ITP mice was lower than that in ITP group,and there was no significant difference between the two groups(P=0.2);the proportion of spleen M1 cells in LPS infected ITP mice was higher than that in LPS group,and there was significant difference between the two groups(P=0.02).The adhesion ratio of platelets in M1 cells of LPS infected ITP mice was higher than that of ITP group,and there was no significant difference between the two groups(P=0.6);the adhesion ratio of platelets in M1 cells of LPS infected ITP mice was lower than that of LPS group,and there was significant difference between the two groups(P=0.002).Conclusions:Infection is a common complication in patients with primary immune thrombocytopenia.Gram-negative bacteria infection is a common pathogen of fine bacteria infection,and LPS is the main pathogenic factor of gram-negative bacteria.Our experimental results show that LPS infection can reduce the low range of platelet count in ITP mice,reflect the expression of CD4+CD25hiFoxp3+Treg cells in ITP mice,affect the proportion of monocytes,neutrophils and macrophages Ml and the adhesion ratio to platelets,and aggravate the immune imbalance in ITP mice.To sum up,LPS may aggravate platelet destruction in patients with ITP through a variety of mechanisms.Significance:Infection is a common clinical complication of primary immune thrombocytopenia.Patients with infection complicated with ITP often have clinical manifestations such as continuous decrease of platelet count,poor response to drug treatment,severe bleeding symptoms and so on.Through the study of LPS infection complicated with ITP mice,to explore the related reasons of LPS aggravating thrombocytopenia,to provide scientific basis for clinical workers,and to further explore the treatment plan.