Study On T Cell Subsets And The Differential Diagnostic Indexes IL-6, CRP And PCT In Children With Sepsis

Part ? Study on T cell subsets in children with sepsisThe purpose of this study is to explore the role of different T cell subgroups in the pathogenesis of sepsis in children.Flow cytometry was used to detect the changes in the activation status and the number of T cell subgroups in the peripheral blood of children with sepsis;healthy children were selected as the control group.Compared with healthy children,CD4+ T cells of children with sepsis in the peripheral blood did not change significantly(Z = 1.945,P = 0.052);even the ratio decreased and the median level dropped from 34.6%to 30.7%(Z = 2.257,P = 0.024).However,the number of CD8+ T cells in the blood of children with sepsis increased,and the median level increased from 0.2x109/L to 0.4x109/L(Z=-2.404,P = 0.016).In addition,CD3+CD8+HLA-DR+ cell level significantly increased,and the median level increased from 4.2%to 24.3%(Z =-5.370,P = 0.000).There was a large heterogeneity in the hospitalization time of sepsis in clinical patients.Compared to patients with a mean hospital time of 6 days,patients with a median hospital stay of 13 days had a lower CD3+CD4+CD25+ cells percentage,while the percentage of CD3+CD8+HLA-DR+ was higher,resulting in a more apparent rise of CD3+ CD8+HLA-DR+/CD3+CD4+CD25+.To sum up,the relative reduction of CD4+ T cell and its activation level no obvious rise,and the increase of CD4+CD25+ regulatory T lymphocytes and its effector molecule TGF-P may be related to the pathogenesis of sepsis.The decrease in the number of CD8+CD25+ regulatory T cells and the over activation of CD8+ T cells may be the cause of multiple organ damage in sepsis patients.The increase of CD3+CD8+HLA-DR+/CD3+CD4+CD25+ was associated with the extended course of sepsis.Part ? Study on the value of IL-6,CRP and PCT in the differential diagnosis of sepsis in childrenIn order to evaluate the abilities of CRP,PCT and IL-6 to differential diagnosis sepsis and to discriminate gram-positive from gram-negative sepsis by ROC analysis,we performed a prospective observational study.Blood samples of sepsis children were collected as during December 2014 to December 2016,the CRP,PCT and IL-6 levels were detected before and after treatment.The comparisons between two groups were performed using the ?2 test for categorical variables and the Mann-Whitney U test(for two groups)for continuous variables.Receiver operating characteristic curve was used to assess the diagnostic value of CRP,PCT and IL-6 to differential diagnosis sepsis and to discriminate gram-positive from gram-negative bacteremia by MedCalc software.Compared to healthy children,the levels of CRP,PCT and IL-6 increased significantly.When sepsis occurred,the median level of serum IL-6 increased from 2.75 pg/mL to 28.0 pg/mL(Z =-5.614,P = 0.000);the median level of PCT increased from 0.028 ng/L to 0.16 ng/L(Z =-5.550,P = 0.000);the median level of CRP levels increased from 3.0 mg/L to 9.5 mg/L(Z =-3.755,P = 0.000).Using these three indicators to differential diagnosis sepsis,the AUCs for CRP,PCT and IL-6 were 0.881,0.877 and 0.754,respectively.Appropriate combination of these indicators can improve their differential diagnosis efficacy,the combination of IL-6 and PCT had the highest cost performance,when taking any one of them increases as diagnostic criteria to identify sepsis,sensitivity can reach 87.6%;when both of them increased at the same time,the diagnostic specificity was 100%.The levels of CRP,PCT and IL-6 were sharply elevated in sepsis patients caused by gram-negative bacteria compared with gram-positive bacteria,and combination of these indicators cannot improve their efficacy to discriminate gram-positive sepsis from gram-negative sepsis.But when IL-6 less than or equal to 75.7 pg/mL and CRP is less than or equal to 16 mg/L,the specificity was 91.3%to discriminate gram-positive from gram-negative sepsis,when taking any of these three indicators increases as diagnostic criteria,the diagnostic sensitivity was up to 89.4%.To sum up,CRP,IL-6 and PCT can be used to differential diagnosis sepsis and to discriminate gram-positive sepsis from gram-negative sepsis,and appropriate combination of these indicators can improve diagnostic efficacy.