Study Of Blood And Urine PrP~C Levels In The Identification Of Autoimmune Encephalitis And Viral Encephalitis

Objective:Autoimmune encephalitis(AE)and viral encephalitis(VE)are central nervous system diseases with different etiology,pathogenesis and treatment modalities in two groups,but with similar early clinical manifestations and laboratory tests.In this study,the clinical data of two groups of patients were analyzed,and blood and urine samples were collected,the expression levels of cellular prion protein(PrP~C),which plays an important role in central nervous system,were compared and analyzed in order to xplore indicators of differential value and enable clinical patients to benefit from early differential diagnosis and treatment.Methods:Patients who were hospitalized in the First Hospital of Jilin University from January2022 to February 2023 were included in the AE group(N=51)and VE group(N=52),and their general data,clinical manifestations,laboratory results,imaging and electrophysiological examination results were collected.The GCS score on admission and m RS score on discharge were recorded.The blood and urine samples were collected,centrifuged on the same day and stored at–80℃.The content of PrP~C in the samples was detected by ELISA method.SPSS26.0 software was used for statistical analysis such as difference and correlation of the obtained data.We combined the blood PrP~C content with early clinically available indicators that were valuable for the differential diagnosis of AE and VE,and then applied binary Logistic regression to establish a prediction model for the differential diagnosis of AE and VE and to evaluate the model effectiveness.Results:1.In terms of underlying diseases,the tumor merger rate of patients in the AE group was higher than that in the VE group(P<0.05).In terms of clinical symptoms,patients with VE mainly suffered from acute onset,while the patients with subacute and chronic onset in AE group were more than those in VE group.Compared with the patients with VE,the patients with AE were more likely to have epilepsy and cognitive impairment,and the patients with VE had more fever than those with AE(P<0.05).In terms of blood and urine laboratory tests,the absolute values of eosinophils,high density lipoprotein and chlorine in blood of patients in AE group were higher than those of patients in VE group.The absolute values of neutrophils,hemoglobin concentration,Hypersensitive C-reactive protein,globulin,total bilirubin,indirect bilirubin,triglyceride and creatinine of patients in VE group were higher than those of patients in AE group(P<0.05).In cerebrospinal fluid examination,the percentage increased protein content,increased lumbar puncture pressure,increased white blood cell count and Ig G in the VE group was higher than that in the AE group.The protein content,white blood cell count,pressure,and Ig G value in cerebrospinal fluid in VE group were higher than those in AE group,while the cerebrospinal fluid glucose value of patients in AE group was higher than that in VE group(P<0.05).In terms of imaging and electrophysiology,the incidence of abnormality of hippocampus and background electroencephalogram frequency change in the AE group was higher than that in the VE group.The probability of background electroencephalogram rhythm changes and abnormal waves originating from frontotemporal region in VE group was higher than that in AE group(P<0.05).2.The PrP~C contents in blood and urine of patients in VE group were higher than those in AE group.There was no difference in blood PrP~C content among different pathogenic antibodies AE encephalitis or among different pathogens VE.In AE group,there was a significant correlation between the serum PrP~C content and the severity of the disease(P<0.05),with the correlation coefficient of 0.304.In VE group,there was no significant correlation between serum PrP~C level and the severity of the disease(P>0.05).The correlation between the serum PrP~C level and the disease prognosis score in AE Group and VE group was analyzed,but no correlation was found between the two groups(P>0.05).With the progression of the disease,the blood PrP~C level in the VE group during the clinical recovery period was lower than that detected for the first time(P<0.05).For patients in the AE group,there was no significant difference in blood PrP~C content between the last and first time according to the condition change(P>0.05),but blood PrP~C content in 62.5%of patients with AEs increased first and then decreased during the course of disease between the acute phase and the recovery phase.3.We combined blood PrP~C with tumor,fever,cognitive impairment,epilepsy,absolute neutrophil value,indirect bilirubin value,cerebrospinal fluid protein content,increased white blood cells in cerebrospinal fluid,and imaging lesion located in hippocampus.We established a predictive model of differential diagnosis by using AE as a positive outcome and VE as a control,The results showed that the model fitted well with the original real data,and the accuracy could reach 86.4%.The evaluation using ROC curve showed AUC=0.926(95%CI:0.875–0.976,P<0.001),with the maximum Rodon index of 0.786,sensitivity of0.882 and specificity of 0.904.Conclusion:1.The content of PrP~C in blood and urine of VE was higher than that of AE,indicating that PRP~C had the potential to be a differential diagnostic marker of the two diseases.2.The blood PrP~C content in AEs was positively correlated with the severity of the disease.3.PrP~C combined with early available and valuable clinical indicators can establish a predictive model that aid in early differential diagnosis.