The Clinical Characteristics Of Japanese Encephalitis And Related Research Of S100B Protein

Objective: Japanese encephalitis (JE), caused by Japanese encephalitisvirus (JEV) infection, is an important viral encephalitis which is prevalent inAsian and Pacific areas. Most of the JEV infections are asymptomatic. Theclinical syndrome varies from a nonspecific febrile illness to severeencephalitis. With high mortality and serious sequela, the encephalitissyndrome is characterized by high fever, conscious disturbance, seizures, focalneurological deficit and meningeal irritation sign, etc. JE is regarded as adisease of children in the endemic areas. Owing to a wide application of JEvaccine, the morbidity of JE decreased obviously. However, an outbreak wasstill occurred in some districts, and the number of adult infections is increasing.Therefore, it is of great significance in clinical to diagnosis and evaluate theseverity of JE as soon as possible. S100B, as a sensitive marker when centralnervous system (CNS) is damaged, has attached attention currently by manyscholars in clinical. In this study, the S100B content in cerebrospinal fluid(CSF) was measured to investigate the clinical characteristics of the JEpatients and to explore the role of S100B in the brain tissue damage of JEpatients.Methods: A total of92patients with107CSF samples, who werediagnosed as JE on the basis of clinical features and positive IgM antibodiesagainst JEV according to the Epidemic Prevention Station of Shijiazhuang,measured by enzyme-linked immunosorbent assay (ELISA). All the sampleswere collected from patients treated in the Second Hospital of Hebei MedicalUniversity from August2013to October2013. To clarify the clinicalcharacteristics of the patients with JE, we collected the results of CSF routine,biochemical examination, CSF cytology, imaging, EEG, etc. Finally, a total of57CSF samples from45JE patients with completely information were identified as the experimental group, which were divided into different groupsbased on the course, severity and imaging findings of JE. And12cases werechosen as the control, including2cases of peripheral neuropathy,1case ofbenign intracranial hypertension, lacunar infarction, venous sinus thrombosis,facial paralysis and vascular headaches, and5cases of outpatients excludedinfection of the CNS by lumbar puncture.All the CSF specimens, collecting after lumbar puncture, were submittedto take cerebrospinal fluid routine, biochemical, and cytology seriesexamination (MGG pigmentation, alcian blue pigmentation). Moreover, theS100B proteins of45JE patients with completely information were measuredby ELISA.Results:1Epidemiology: All patients male: female=55%:45%. Thenumber of patients increased in August2013,and reached the peak inSeptember2013. There were only4patients younger than15years. While thepatients15-45years old accounted for50%and45-65years old accounted for43.38%.79%patients were farmers.2According to the results of CSF routine and biochemical examination,the white blood cells and protein content increased slightly while the glucoseand chloride content were normal in most of the patients with JE. The JEpatients were divided into several groups, including mild, medium, severesymptoms group, acute phase group and convalescence group. The whiteblood cells and protein content in CSF of all the subgroups increased and thedifferences were statistically significant (P <0.05), as compared with thecontrol group. While no statistically significant differences of glucose andchloride content in CSF were observed between the subgroups and controlgroup (P>0.05).3It was mixed cell reaction in the CSF cytology of patients with JE at theearly stage. Then the neutrophils decreased and the lymphocytes increasedgradually. We also found activated monocytes and plasma cells during thecourse of disease. At convalescence, the CSF cytology turned tobe lymphocyte reaction or typical lymphocyte reaction. The imaging of JE was characterized by bilateral thalamus involvement, basal ganglia andhippocampus were also common. It was mostly showed moderate to severeabnormality in EEG, and it could be recovered after treatment.4The content of S100B protein in CSF: In mild symptoms group,average content value of S100B is531.94±166.95pg/ml (acute phase group:627.77±155.93pg/ml，convalescence group:412.15±83.14pg/ml). In mediumsymptoms group, average content value of S100B is852.25±309.75pg/mlpg/ml(acute phase group:822.76±275.99pg/ml, convalescence group:907.03±382.24pg/ml). In severe symptoms group, average content value ofS100B is1045.60±468.93pg/ml (acute phase group:1155.5±559.22pg/ml,convalescence group:923.40±333.21pg/ml).The S100B average content valueis629.38±215.49pg/ml,950.93±364.52pg/ml,864.53±409.94pg/ml，748.22±371.22pg/ml， in MRI-no-lesion group， MRI lesions group，acutephase group and convalescence group respectively. While in control group theaverage content value is295.29±97.20pg/ml. The contents of S100B in allsubgroups are higher than the control group, and the differences are significantin statistics (P <0.05). Significant differences were observed between mild vs.medium symptoms group, mild vs. severe symptoms group, MRI-no-lesiongroup vs. MRI lesions group and acute phase of mild symptoms group vs.convalescence group of mild symptoms group (P <0.05). But no significantdifferences were observed among the rest of the subgroups (P>0.05).5Twelve JE patients took lumbar puncture more than once. The averagecontent value of9patients in6~9days after onset is1126.0±555.78pg/ml,while in12~18days after onset is1007.4±366.24pg/ml. Another8patients,the S100B average content is869.83±413.40pg/ml in6~9days after onset and823.87±218.11pg/ml in more than20days after onset. The comparisons areboth not significant differences in statistics (P>0.05).Conclusions:1Japanese encephalitis patients mainly are children under15years old, but there is an outbreak of Japanese encephalitis infection inadults trend in some endemic areas.2Mixed cell reaction in the CSF cytology of patients with JE resist longer than other virus encephalitis.3The imaging of JE is characterized by bilateral thalamus involvement.Basal ganglia and hippocampus are also common sites of involvement. Inendemic areas and the epidemic season, bilateral thalamic involvement shouldbe highly suspected as JE.4For the Japanese encephalitis patients, the content of S100B protein incerebrospinal fluid is higher. There is kind of relevance between the high levelof S100B protein in cerebrospinal fluid for Japanese encephalitis patients withthe severity, duration and imaging. Dynamic observation of S100B levels is ofgreat significance for judging the patients’ condition and curative effect.