Analysis Of Clinical Characteristics And Preliminary Study Of Differential Diagnosis Biomarkers Between Autoimmune Encephalitis And Viral Encephalitis

【Objective】 To retrospectively analyze the clinical characteristics between autoimmune encephalitis(AE)and viral encephalitis(VE),and construct a nomogram of differential diagnosis between two groups.In addition,exosomes in serum were isolated to detect the expression of mi RNAs and the viability of their use as a marker for differential diagnosis of anti-N-methyl-D-aspartic acid receptor encephalitis(anti-NMDAR encephalitis)been the most common type of AE was preliminarily explored,which may provide new ideas and experimental basis for early identification of AE.【Methods】 1.Retrospective analysis of clinical features between autoimmune encephalitis and viral encephalitis We collected 81 cases of AE and 79 cases of VE in the first affiliated Hospital of Fujian Medical University from January 2016 to February 2021.The general information such as age,sex,hospitalization time,the results of laboratory tests such as blood routine,CRP,biochemistry,CSF biochemical test,CSF routine and the results of brain magnetic resonance imaging(MRI),electroencephalogram(EEG)of all patients were collected.SPSS 26.0 software was used to analyze and compare the difference between the two groups.Then we evaluate the application effectiveness of the new diagnostic criteria of AE published in the Lancet in 2016 in patients with AE in our center.In addition,we used Lasso logistic regression to screen the variables included in the model through R3.5.3 software,and constructed a nomogram to assist in the differential diagnosis between AE and VE.2.A preliminary study on micro RNAs derived from serum exosome as a biomarker for differential diagnosis of anti-NMDAR encephalitis From October 2018 to November 2020,we collected 30 cases of anti-NMDAR encephalitis,30 cases of VE and 30 cases of non-inflammatory neurologic disorders as control patients with matching age and sex in the first affiliated Hospital of Fujian Medical University.The exosomes in serum were extracted and identified by transmission electron microscopy,nanoparticle tracking analysis(NTA)and western blot.Then extracted the mi RNAs from exosome and detected the expression of let-7b and mi R-140-5p in AE group,VE group and control group through real-time quantitative PCR(q PCR).At the same time,the expression of C3,C4 and high sensitivity CRP(hs-CRP)was detected in the three groups.The difference was statistically analyzed by Graph Pad Prism 8 software(P<0.05).Then the receiver operator characteristic curve(ROC curve)of the subjects was made to analyze the application value of mi R-140-5p combined with serum C3 in the differential diagnosis of anti-NMDAR encephalitis.【Results】 1.Retrospective analysis of clinical features and auxiliary examination between autoimmune encephalitis and viral encephalitis Compared with the VE group,the AE group had younger age at onset,longer hospitalization time,more epilepsy and less intracranial infection as the preliminary diagnosis and the difference was statistically significant(P < 0.05).Among the main clinical manifestations,epilepsy,mental and behavior disorder,memory deficit and sleep disorder occurred more frequently in AE group than in VE group,while prodromal symptoms,fever and headache were less common in AE group(P < 0.05).In brain MRI and EEG findings,except insular lobe were more common in AE group,there was no significant difference in other items between two groups.In laboratory examination,platelet count,total protein,albumin,GFR,HDL,APOA1,APOA1/B,calcium,CSF chlorine in AE group were higher than those in VE group,while ESR,total bilirubin,indirect bilirubin,creatinine,cystatin C,glucose,total triglyceride,VLDL,APOB,CSF protein,CSF lactic acid,CSF Ig G,CSF albumin and CSF albumin index in VE group were lower in AE group(P < 0.05).In the case of unknown autoantibodies,the sensitivity,specificity and accuracy of the 2016 Lancet AE guidelines applied to AE,marginal encephalitis and anti-NMDAR encephalitis were 95.1%,36.7%,66.3%,12.5%,97.2%,88.8% and 18.5%,95.8%,64.4%,respectively.In addition,we separated the total case into training set and verification set according to 8:2 proportion by R3.5.3 software,and through Lasso logistic regression screened variables from training set.When the λ value was 0.098,the optimal model was obtained.The variables included headache,epilepsy,mental and behavioral abnormalities,memory deficit,GFR,APOA1/B,CSF protein,and then constructed nomogram with a training set AUC value of 0.974,a sensitivity of 85.71% and a specificity of 100%.2.A preliminary study on micro RNAs derived from serum exosome as a marker for differential diagnosis of anti-NMDAR encephalitis The particles isolated from serum showed round or cup-shaped vesicles wrapped by phospholipid bilayers under electron microscope and diameter about 100 nm by NTA.The results of western blot showed the high expression of exocrine marker proteins CD63 and TSG101.The expression of mi R-140-5p in NMDAR group was significantly higher than that in VE group,and the expression of C3 was the lowest in NMDAR group.In the differential diagnosis between anti-NMDAR encephalitis and VE,the AUC value of mi R-140-5p was 0.713(95% CI: 0.579-0.824),the sensitivity was 68.97%,and the specificity was 79.31%,while serum C3 was 0.729(95%CI: 0.597-0.838),the sensitivity was 79.31%,and the specificity was 58.62%.The AUC value of mi R-140-5p combined with serum C3 was 0.757(95%CI: 0.627-0.860),the sensitivity was 72.41%,and the specificity was 72.41%.【Conclusions】 Compared with VE group,AE group was more likely to occur in young patients,and prodromal symptom was rare,and epilepsy,mental and behavioral disorder,memory loss and sleep disorders are more common.In laboratory examination,serum total protein,albumin,GFR,HDL,APOA1,APOA1/B and CSF chlorine in AE group were higher than those in VE group,while serum total bilirubin,indirect bilirubin,TG,VLDL,APOB and CSF protein in AE group were lower than those in VE group.In the case of unknown autoantibodies,the diagnostic efficiency of 2016 Lancet diagnostic guidelines applied to AE cases in China is low and needs to be further improved.The nomogram constructed in this study has good prediction efficiency to provides a convenient and reliable tool for the early identification of AE and VE.Serum exosomes were isolated successfully and mi R-140-5p derived from serum exosome combined with C3 is a potentially differential diagnostic marker of anti-NMDAR encephalitis.