Role Of Nmdar Antibody Levels In Differential Diagnosis And Security Evaluation Between Encephalitis

Background:Autoimmune encephalitis is a central nervous system disease caused by auto-antibody,which belongs to a relatively new category in encephalitis.10 years ago,Dalmau et al first discovered and reported paraneoplastic ovarian teratoma associated with anti N-methyl-Daspartate receptor encephalitis,according to the report on the turning point of autoimmune encephalitis sphere.With the development of detecting techniques of antibodies in recent years,various types of autoimmune encephalitis have been reported,which can be divided into two categories:anti intracellular antigen antibody,anti nerve cell surface/synaptic protein antibody.NMDAR encephalitis is an autoimmune encephalitis which is the most common and the most typical type,accounting for about 80% of the patients with autoimmune encephalitis.It mainly occurs in young women and children which has a close relationship with malignant teratoma,but little tumor correlation.This subtype of autoimmune encephalitis is an inflammation mediated by N-methyl-D-aspartate glutamate receptor immunoglobulin G attacked cell surface N1 subunit of the neurons,leadingto neuron dysfunction caused a series of clinical symptoms,the main symptoms are fever,headache and other premonitory symptoms,mental and behavior disorder,involuntary movement,epilepsy,the recent decrease in memory,autonomic nerve dysfunction.If treated timely,the disorder is reversible.However,if not treated in time,long-term inflammatory response and N-methyl-D-aspartate mediated glutamate toxicity may cause permanent destruction of neuronal cells.For NMDAR encephalitis patients,early diagnosis and therapy can have a relatively good prognosis and can experience a return to their baseline functional status with complete resolution,and the subsequent review of imaging histories of abnormal lesions may also be completely absorbed and disappeared.Therefore,early diagnosis and treatment is very crucial for the patients with NMDAR encephalitis,which have the direct bearing on the therapeutic effect and prognosis of NMDAR encephalitis.However,the main pathogen of encephalitis can be divided into two categories,namely autoimmune and infection.Detection of autoantibadies may be relatively easy in rencent years,on this count the number of cases of autoimmune encephalitis has been increased singnificantly,which may bring an illusion to clinicians that the morbidity of autoimmune encephalitis is higher than infectious encephalitis.This may be due to the detection of infectious pathogens,especially the detection of PCR virus isnot comprehensive or technical limitations,resulting in the diagnosis of viral encephalitis may be insufficient.In fact,autoimmune encephalitis accounts for about 10%-20% of encephalitis,which is lower than that of viral encephalitis.Therefore,it is very vital for the early diagnosis of autoimmune encephalitis and viral encephalitis,which is directly related to the therapeutic strategy,therapeutic effect and long-term prognosis of patients.Objective: N-methyl-D-aspartate receptor(NMDAR)encephalitis is one of most common and best characterized subtypes of autoimmune encephalitis classical seen in young women and children.NMDAR encehalitis has various clinical manifestations.Infectious pathogeny may be the most common reason for encephalitis,of which virus account for the most.Sometimes the clinical featrues of virus and NMDAR encephalitis can be analogous.The aim of this artical is mainly to discuss the effect of NMDAR antibody levels in differential diagnosis and security evaluation between NMDAR encephalitis and viral encephalitis.Methods:Fifty-three patients with NMDAR encephalitis were selected as the study group and 22 patients with viral encephalitis as the control group.The clinical data of patients with anti-NMDAR encephalitis or virus encephalitis were analyzed together with the clinical presentations,level of NMDAR antibody in CSF and serum.Results:1.Among the 53 patients with anti-NMDAR encephalitis,32 cases were female patients and 21 cases were male.The average age was(45.12±10.13)years old.Among the 22 patients with virus encephalitis,15 cases were female patients and 7 cases were male.The average age was(47.22±12.49)years old.There were no significant differences between the two groups in sex ratio and the average age of onset.2.Among the 53 patients with anti-NMDAR encephalitis,there were12 cases(22.6%)with history of prodromal infenction,24 cases(45.3%)with fever,27 cases(50.9%)with disturbance of consciousness,32 cases(60.4%)with seizure,21 cases(39.6%)with involuntary movement,23cases(43.4%)with headache,39 cases(78.1%)with psychological and behavioral abnormalities.Among the 22 patients with virus encephalitis,there were 14 cases(63.6%)with history of prodromal infenction,21 cases(95.5%)with fever,3 cases(13.6%)with disturbance of consciousness,1 cases(4.6%)with seizure,2 cases(9.1%)with involuntary movement,14 cases(63.6%)with headache,0 cases(0%)with psychological and behavioral abnormalities.Compared with patients with viral encephalitis,there was a significant difference in the clinical manifestations of anti-NMDAR encephalitis compared with the history of prodromal infection(X2=11.54,P=0.00),fever(X2=16.31,P=0.00),disturbance of consciousness(X2=9.02,P=0.00),seizure(X2=19.67,P=0.00),involuntary movement(X2=6.82,P=0.00),psychological and behavioral abnormalities(X2=27.44,P=0.00).3.The average concentration of NMDAR antibody in the serum of patients with anti-NMDAR encephalitis is 14.03 ± 5.62ng/ml,and 29.31 ±4.37ng/ml in the CSF.The average concentration of NMDAR antibody in the serum of patients with viral encephalitis is 3.94±2.97ng/ml,and 12.34±3.19ng/ml.The levels of NMDAR antibody were statistically different in serum(t=7.95,P=0.00)and CSF(t=16.46,P=0.00).while the CSF concentrations of NMDAR antibody were significantly higher than that in the serum.4.Among 11 severe anti-NMDAR encephalitis patients,9 cases with high level NMDAR antibody in serum,10 cases with high level NMDAR antibody in CSF.Among 42 mild anti-NMDAR encephalitis patients,2cases with high level NMDAR antibody in serum,2 cases with high level NMDAR antibody in CSF.The difference of NMDAR antibody between high and low levels of CSF(X2=36.94,P=0.00),and serum(X2=31.47,P=0.00)was statistically significant.Conclusions:1.The difference of clinical characteristics between anti-NMDAR encephalitis patients and virus encephalitis patients was statistically significant.History of prodromal infenction,fever,disturbance of consciousness,seizure,involuntary movement,psychological and behavioral abnormalities were moer common in anti-NMDAR encephalitis patients.2.The concentration of NMDAR antibody in patients with anti-NMDAR encephalitis was higher than that in patients with viral encephalitis.And the concentration of NMDAR antibody in CSF was higher than that in serum of all patients,which may indicate that NMDAR antibody in CSF is more sensitive.There are some differences in serum and cerebrospinal fluid concentrations of NMDAR and specific levels can be used as main point of differential diagnosis.3.The concentration of NMDAR antibody in patients with severe anti-NMDAR encephalitis was higher than that in patients with mild anti-NMDAR encephalitis no matter in CSF or serum.And this discrepancy was statistically significant,indicating that the higher concentration of NMDAR antibody,the more severe of anti-NMDAR encephalitis.