The Exploration Of Traumatic Complication Biomarkers At Genetic, Molecular, Cellullar Levels And The Analysis Of Their Clinical Implications

BackgroundIn 2013,about 973 million people sustained injuries that required medical attention and 4.8 million people died from trauma.Meanwhile,trauma accounted for more than 10% of the global burden of disease.So trauma remains to be a severe public health problem worldwide.Although significant advances in the emergency care system in recent years,patients who survived from initial trauma still suffer from a series of complications after admission.Sepsis and multiple organ dysfunction syndrome(MODS)are common serious complications in major trauma patients.Therefore,it is important to prevent sepsis and MODS in the treatment of trauma.Despite years of investigation and advance in critical care management,morbidity and mortality from sepsis remain unacceptably high.Till now,there is no specific treatment for sepsis.So early identifying high-risk patients and early diagnosis is the key to prevent sepsis.Biomarker generally refers to a measurable indicator of some biological state or condition,and is the most common way to early-warning and diagnosis of sepsis.At present a number of studies have reported the role of biomarkers in diagnosing sepsis,but did not get satisfactory results.Sepsis is a clinical syndrome which involves multiple tissues,organs and systems.The pathogenesis of sepsis is extremely complex.A single biomarker can not accurately diagnose sepsis.So we aimed to establish a diagnosis model combining biomarkers from genetic,molecular,and cellular levels.MethodsThirteen tag SNPs(tSNPs)were selected from CXC chemokine genes by using a multi-marker tagging algorithm of Tagger software.Three independent cohorts including 1700 injured patients were prospectively recruited.Selected SNPs were genotyped by an improved multiplex ligation detection reaction(iMLDR)method.Genotype distribution of each tSNPs was determined by counting.The association of SNPs with sepsis risk and MOD scores were determined by dominant and recessive genetic models.The peripheral blood collected from trauma patients within 2 hours after admission was incubated with LPS(100ng/ml)at 37? for 4 hours.Nine cytokines productions in plasma were measured by enzyme-linked immunosorbent assay.Monocyte HLA-DR expression,neutrophil CD64 index,CD4/CD8 ratio,NK cells and Tregs cells were measured by flow cytometry,and 38 cytokines were measured by a multiplexed liquichip assay at days 1,3,5,7,and 14 postinjury.ResultsIn the derivation cohort,rs1429638 and rs2297630 were significantly associated with the susceptibility to sepsis in trauma patients.The associations were also confirmed in the two validation cohorts.In all included patients,rs1429638 was significantly associated with the susceptibility to sepsis and MOD scores,and rs2297630 was closely associated with the susceptibility to sepsis.The rs2297630 polymorphism was significantly associated with IL-6 production.The patients who carried the rs2297630 A allele had a higher level of IL-6 production.Data from linear regression analysis also indicated that the association of rs2297630 with IL-6 production was significantly in allele-dose dependent.G-CSF,GM-CSF,IL-10,MDC and IL-15 were selected as candidate biomarkers for sepsis.A combined measurement of these five biomarkers allows for a good separation of sepsis patients from trauma patients,and the AUC for diagnosis sepsis was 1.00 at days 3,5,and 7 postinjury.In the early stages of trauma,the AUCs for diagnosis of sepsis were the best to 0.84 for HLA-DR and 0.80 for CD64.A combined measurement of HLA-DR,CD64 and CD4/CD8 could identify sepsis patients at 2 days before clinical diagnosis,and the AUC for prediction of sepsis was 0.83.ConclusionsIn the study we investigated the clinical relevance of genetic variants within the CXC chemokine genes.The results indicated that rs1429638 polymorphism was significantly associated with the susceptibility to sepsis and MODS,and rs2297630 polymorphism was closely associated with the susceptibility to sepsis in trauma patients.The two SNPs could serve as genetic markers for traumatic complication.Monocyte HLA-DR expression,neutrophil CD64 index and CD4/CD8 ratio seem to be potential markers for the diagnosis of sepsis,and combining these markers could improve the diagnostic efficiency.In addtion,a combined measurement of multiple cytokines may be a promising method to diagnose sepsis.