Abstract: Objective To explore the expression of acetylcholinesterase (Ache), P-selectin, and cyclin-dependent kinase 5 (CDK5) in viral encephalitis (VE) and their correlation. 
Methods A total of 130 patients with viral encephalitis who underwent physical examination, presented to Department of Neurology or treated in our hospital were selected as the research subjects, and included in the research group. The patients were divided into acute phase group (n=85) and recovery phase (n=45) according to severity of their illness. According to the clinical manifestations of patients, they were divided into mild group (n=76) and severe group (n=54). Sixty healthy people who underwent physical examination in our hospital during the same period were used as the control group. The butyrylthiocholine substrate method was used to detect the level of Ache, the enzyme-linked immunosorbent method was used to detect the level of serum P-selectin, and the CDK5 separation kit was used to detect the level of CDK5. The Ache, P-selectin, and CDK5 levels of patients in the research group and control group, acute phase and recovery phase, and severe and mild groups were observed. The correlation between Ache, P-selectin and CDK5 in patients with VE was analyzed. The ROC curve was used to compare the diagnostic value of detection of Ache, P-selectin, and CDK5 alone or in combination in VE. 
Results The levels of Ache, P-selectin and CDK5 were significantly higher in the research group than in the control group (P＜0.05), higher in the acute phase than in the recovery phase (P＜0.05), and higher in the severe group than in the mild group (P＜0.05). Ache, P-selectin and CDK5 protein expressions were positively correlated (P＜0.05). The diagnostic value of combined diagnosis was significantly higher than that of Ache, P-selectin, and CDK5 alone (Z=2.765, 2.563, 2.925, all P＜0.05). 
Conclusion Ache, P-selectin and CDK5 are all involved in the pathogenesis of VE patients. They are expressed at different levels at different stages of the onset, and there is a positive correlation between each two indicators. Therefore, they can be used as a basis for diagnosis and treatment of patients with VE. 

Key words: encephalitis, viral, acetylcholinesterase, P-selectin