The Antibody Specificity Index And Cerebrospinal Fluid Cytology In The Diagnosis Of Some Viral Encephalitis

Objective: To evaluate the sensitivity and particularity of the antibody specificity index in the diagnosis of viral encephalitis. Expected to find a good method of etiological diagnosis for viral encephalitis,which is cheap, convenient and has ideal sensitivity and particularity . The level of the diagnosis of viral encephalitis was expected to elevate. Wish it is helpful for the treatment and investigation. The feature of CSFC (cerebrospinal fluid cytology) in the central nervous system disease was studied further.Methods: Study group have 36 patients suffer from viral encephalitis which was clinical diagnosis. The serum and the first CSF sample were gathered in 3 days after they came in, the second CSF sample were gathered at the second or the third week. All the sample were preserved in cryogenic box at -20oC, and were treated in batch. The pathogen-specific antibody of the IgG class was quantitative in-vitor assayed by the ELISA test kit from EUROIMMUN Medizinische Labordiagnostika AG. In the assay, serum samples were diluted 1:404 in sample buffer, CSF samples were diluted 1:2 in sample buffer, standard curve was determined by the CSF calibrators(C A to C D), then the concentration of antibodies of IgG were obtained. The volume dose of the IgG was obtained from immunity laboratory by nephelometry. The quotient of the portion of pathogen-specific antibodies in total IgG of CSF and the portion of pathogen-specific antibodies in total IgG of serum is the relative CSF/serum quotient(CSQrel). A CSQrel above 1.5 is positive. In the study, the antibodies against HSV-1, EBV, HCMV were detected. A etiological diagnosis was made by the positive result. Total 27 patients suffer from others infective diseases of CNS (cerebral tubercu- losis14, suppurative meningitis2, brain cysticercosis4) and demyelinating diseases (multiple sclerosis5, Guillain-Barre syndrome2) composed control group. The positive rate of viral antibody specificity index was Compared; the sensitivity and particularity of the viral antibody specificity index in the diagnosis of viral encephalitis was evaluated. The CSFC of two groups was studied, and the appearance of CSFC of viral encephalitis was investigated. The clinical feature of the two infective groups was investigated to find the difference. Used SPSS12.0 for data analysis; enumeration data was treated byχ~2 test , size of testα=0.05.Result: 1 In the study group 6 of the 36 patients (17%) were herpes simplex virus encephalitis, 3 (8%) were Epstein- Barr virus encephalitis, 2(6 % ) were human cytomegalovirus encephalitis. In the control group 1 of the 27 patients got a positive result of antibody specificity index, the antibody was against Epstein-Barr virus. There was not overlapped positive result in the study group. The positive rate of viral antibody specificity index in study group was 31%, in the control group was 4%; the particularity of this method was 92%in the diagnosis of viral encephalitis.2 Most of the two group patients had abnormal cerebrospinal fluid cytology, in the study group was 86%, in the control group was 78%. The cerebrospinal fluid cytology of the most viral encephalitis patients was lymphocytic reaction; the quantity of neutrophilic leukocyte stepped up at nonage in minority patients. The cerebrospinal fluid cytology of the 6 patients suffer from herpes simplex virus encephalitis was abnormal,and red blood cell was find in the cerebrospinal fluid in two of them. The cerebrospinal fluid cytology of 2 Epstein-Barr virus encephalitis patients and 2 human cytomegalovirus encephalitis patients was abnormal.3 Some clinical data of the study group and another infective group were discrepant; the emotionai disturbance, meningeal irritation sign and electroencephalogram were discrepant obviously. Conclusion: Viral antibody specificity index is a value for the intrathecal pathogen-specific antibody production. The pathogen-specific antibody is produced intrathecally after the viral infection in central nervous system when the index is above 1.5.This method has ideal sensitivity and particularity, so we should pay close attention to it. A continuative study with larger sample size and more kinds of virus maybe raise the total positive rate, so that we can get a more satisfactory sensitivity. As a cheap and convenient method it may be very helpful for the treatment and investigation of viral encephalitis. Epidemiology data and clinical situation is the foundation for diagnosis of viral encephalitis. Electroencephalogram and cerebrospinal fluid cytology are important auxiliary examination, they should not be ignored.