The Diagnostic Value Of Serum Interleukin-6 In Relation To Neutrophil Phenotypes And Phagocytosis In Clinical Staging Of Patients With Sepsis

Background: Sepsis is a common complication and consequences in the process of diseases such as microbe infection,severe trauma,burns,major surgery,bleeding as well as hypovolemic shock.It is multiple organ disfunction syndrome(MODS)based on systemic inflammatory response syndrome(SIRS).Sepsis is believed as life-threatening organ dysfunction caused by a dysregulated host response to infection based on the definition of?sepsis 3.0,2016?.Actually,sepsis is not a single infectious disease but is a clinical syndrome in which the initial features are nonspecific,frequently leading to delay of correct diagnosis.Lack of specific laboratory tests for diagnosis of the syndrome contribute to the misdiagnosis.Failure to identify sepsis in the early stages itself usually delays effective treatment,giving rise to high morbidity and mortality.Therefore,an increasing number of researchers are trying to find biomarkers with high sensitivity and specificity for the diagnosis,differential diagnosis,and prognosis of sepsis.In recent years,through continuous in-depth exploration on the pathophysiology of sepsis,it has been gradually discovered that the early stage of sepsis is closely related to host immune state,and cytokines burst induced by pathogenic infection plays an important role in the subsequent process and even decides the consequences of the diseases.Object: The essence of sepsis is the host's immune response to the invasion of pathogenic microorganisms,including innate and adaptive immune responses.Imbalance and dysfunction of immunity lead to metabolic and circulatory disorders in sepsis,inflammatory mediators play a crucial role in pathology of sepsis.Many kinds of proinflammatory factors and anti-inflammatory factors are released.The cascade reaction of cytokines is closely related to the outcome of the sepsis.As a bridge between adaptive and innate immunity,cytokines also play an pivotal part in innate immunity of host.This study aimed to discover the value of IL-6 secretion for the diagnosis and staging of sepsis,and additionally,the relationship between IL-6 level and neutrophil phenotype and phagocytosis was discussed.Meterials: A total of 121 patients in Chaohu Hospital of Anhui Medical University were collected between January 2018 and June 2019.The patients were divided into two groups: the group of systemic inflammatory response syndrome(SIRS,95 cases,including 19 cases of non-sepsis,56 cases of sepsis and 20 cases of septic shock),the group of local infection(26 cases).Meanwhile,20 cases of healthy volunteers from physical examination center in the same hospital were selected as the control group.Cytokines(IL-2,IL-4,IL-6,IL-10,IFN-g,TNF-?),PCT,hs CRP,and WBC counts were measured and the phenotypes(CD64,CD11 b and CD62L)of peripheral blood neutrophils(PBNs)and their phagocytic function were determined.Results:(1)The serum IL-6 and IL-10 concentrations in the cases of SIRS were significantly higher than those of local-infection and control(p<0.01);(2)The IL-6 level in the group of septic shock was highest,followed by the groups of sepsis and non-sepsis consecutively(p<0.01),the IL-10 level was remarkably elevated in the groups of sepsis and sepsis shock compared with the group of non-septic(p <0.01),but no significant difference between the group of septic shock group and sepsis group was noted(p> 0.05);(3)Serum concentration of IL-6 and IL-10 in the patients with Gram-negative bacterial infection were notably elevated when compared with that in Gram-positive bacterial infection(p<0.01);(4)Serum hs CRP,PCT,IL-6,and IL10 concentrations in high IL-6 group signifcantly increased compared with those of low IL-6 group(p<0.01);(5)Expression of CD11 b and CD64 on neutrophils was found to be upregulated in the group of high IL-6 level(p<0.01);(6)The phagocytic percentage and phagocytic index of neutrophils in the group with high IL-6 concentration increased significantly when compared with those in the IL-6 low-level group(p<0.01).Conclusions: Significant increase of serum IL-6 and IL-10 level is closely associated with Gram-negative bacterial infection.The serum level of IL-6 in the patients with sepsis gradually increased as the disease progresses,and the highest level of serum IL-6 may be noted in the patients with sepsis shock,followed by those of sepsis and non-sepsis consecutively.An elevated level of serum IL-6 was frequently accompanied by enhanced neutrophil phagocytosis and high expressions of CD64 and CD11 b in the patients with sepsis.Taken together,examination of serum IL-6,which is closely associated with clinical prognosis of sepsis,is quite valuable for diagnosis of the disease.Thus tracking and monitoring of serum IL-6 may provide a reference for the clinical diagnosis and staging of sepsis,worth being promoted practically.