Clinical Value Of MDSCs PDL1 In The Diagnosis And Prognosis Of Sepsis

Background and purpose:Objective:To determine the expression of programmed death ligand 1(PDL1)on peripheral blood marrow derived suppressor cells(MDSC)in patients with sepsis,and to investigate its clinical value in the diagnosis and prognosis evaluation of patients with sepsis.The correlation between the expression rate of programmed death receptor 1(PD1),cytokines,SOFA score,and APACHII score on lymphocyte subsets and their evaluation ability.Methods:From January 2022 to January 2023,54 patients with sepsis who received complete clinical data from the People’s Hospital of Jiangxi Province were collected,and 17 healthy controls were included.First,sepsis patients were divided into sepsis group(n=13)and septic shock group(n=41)according to Sepsis 3.0 guidelines.Secondly,sepsis patients were divided into survival group(n=25)and death group(n=29)according to 28-day survival conditions,Compare the differences in peripheral blood lymphocyte ratio,PD1 expression on lymphocytes,MDSCs ratio,and PDL1 expression on MDSCs between groups and healthy control groups,and analyze their correlation with T lymphocytes,cytokines,sequential organ failure score(SOFA),and other indicators;The efficacy of PDL1 expression rate on MDSCs in the diagnosis and prognosis of sepsis was analyzed using subject working curve(ROC);Using multivariate logistic regression analysis to screen independent prognostic risk factors for sepsis;Kaplan Meier survival analysis was used to compare the survival rate of patients with different levels of PDL1 expression on MDSCs.Results:1.Compared with the healthy group,the expression rate of PD1 on CD3~+T cells and PD1 on CD4~+T cells in the sepsis group were higher,the number of MDSCs in peripheral blood was significantly increased,and the expression of PDL1 on total MDSCs,M-MDSCs,and PMN-MDSCs was increased.The increase in PDL1 was mainly concentrated in PMN-MDSCs,while the increase in M-MDSCs was not significant.The results were statistically significant(P<0.05).2.The expression rate of PD1 on CD8+T cells was negatively correlated with the CD4+T/CD8+T ratio(r=-0.4549,P=0.0005).3.The expression rate of PDL1,SOFA score,and APACHEII score on total MDSCs in the septic shock group were significantly higher than those in the non shock group,and the difference was statistically significant(P<0.05).4.The expression rate of PDL1,SOFA score,and APACHEII score on total MDSCs in the sepsis death group were significantly higher than those in the survival group,and the difference was statistically significant(P<0.05).5.The multivariate logistic regression model showed that the expression rate of PDL1 on total MDSCs and APACHEII score were independent risk factors for sepsis shock and 28 day death prognosis.6.In septic shock,the ROC curve showed that the AUC of PD-L1 expression rate and APACHII score on total MDSCs were 0.725 and 0.832,the cutoff values were14.63 and 15.5,the sensitivity were 58.5%and 82.9%,and the specificity was 92.3%and 76.9%.Combining the two indicators to predict the AUC of septic shock can increase to 0.891,with a sensitivity of 75.6%and a specificity of 92.3%.7.In the sepsis death group,the ROC curve showed that the expression rate of PD-L1 on MDSCs and the AUC of APACHII score were 0.670 and 0.706,the cutoff values were 14.655 and 13.5,the sensitivity was 65.5%and 96.6%,and the specificity was 76.00%and 48.00%.Combining the two indicators to predict the AUC of septic shock can increase to 0.757,with a sensitivity of 89.7%and a specificity of 56.0%.8.The survival analysis results showed that when the PDL1 expression rate on the total MDSCs was>15.01%,the 28-day mortality rate of sepsis patients was higher(P<0.05)Conclusion:1.The decreased proportion of T lymphocytes and the overexpression of PD1 in the peripheral blood of patients with sepsis,which correlated somewhat with the CD4~+/CD8~+T ratio,suggest that in patients with sepsis the number of immune cells is significantly reduced and the effector function declines,and that T lymphocytes may play an important immunosuppressive role in sepsis through PD1 upregulation.2.The proportion of MDSCs in peripheral blood and the expression of PDL1 are increased,and the levels of anti-inflammatory and pro-inflammatory cytokines are abnormal,indicating that MDSCs may participate in sepsis immune disorders through abnormal PDL1 expression and cytokine levels.3.The expression of PDL1 and APACHEII scores on peripheral blood MDSCs are closely related to the severity of the disease,and they are independent risk factors for sepsis occurrence and 28-day mortality.4.The combined diagnosis of PDL1 expression rate and APACHII score on MDSCs has certain predictive value for the occurrence of septic shock and death,and can provide a certain reference basis for clinical practice.5.When the expression rate of PDL1 on MDSCs is higher,the prognosis of patients is worse,indicating that the expression rate of PDL1 in total MDSCs can serve as a new prognostic biomarker for predicting mortality.