Abstract: Objective To investigate the expression of glial fibrillary acidic protein (GFAP), creatine phosphokinase-BB (CPK-BB), neuron-specific enolase (NSE) and S-100 calcium binding protein (S-100B) in serum and cerebrospinal fluid of adults with viral encephalitis and their relationship with disease severity and prognosis. 
Methods In total, 102 adults with viral encephalitis admitted to our hospital were selected as the observation group, and another 50 patients with migraine, upper respiratory tract infection, and neurological disorders during the same period were included as the control group. The levels of GFAP, CPK-BB, NSE, and S-100B in serum and cerebrospinal fluid in the two groups and the observation group with different disease severity were recorded, and their predictive efficacy was analyzed by plotting the receiver operating characteristic (ROC) and the area under the ROC curve (AUC). The levels of GFAP, CPK-BB, NSE, and S-100B in serum and cerebrospinal fluid of patients with different prognosis were compared, and logistic regression equations were used to analyze the correlation between them. 
Results The GFAP, CPK-BB, NSE, and S-100B levels in serum and cerebrospinal fluid in the observation group were higher than those in the control group, which were higher in severe patients in the acute and recovery stages in the observation group, followed by moderate patients and mild patients (P＜0.05). The levels of GFAP (r=0.587, 0.638, 0.552, 0.568), CPK-BB (r=0.557, 0.593, 0.540, 0.559), NSE (r=0.602, 0.655, 0.587, 0.600), and S-100B (r=0.599, 0.634, 0.575, 0.595) in serum and cerebrospinal fluid of adults with viral encephalitis were positively correlated with the disease severity in the acute and recovery stages (P＜0.05). The ROC curve showed that the diagnostic value of GFAP, CPK-BB, NSE, and S-100B in cerebrospinal fluid for adults with viral encephalitis ［AUC: 0.937］ was superior to that of GFAP, CPK-BB, NSE, and S-100B in combination in serum ［AUC: 0.908］. In the observation group, the levels of GFAP, CPK-BB, NSE, and S-100B in serum and cerebrospinal fluid of patients with sequelae were higher than those of patients without sequelae (P＜0.05). The levels of GFAP (OR: 4.971, 5.311), CPK-BB (OR: 4.986, 5.292), NSE (OR: 5.001, 4.727), and S-100B (OR: 5.453, 4.492) in serum and cerebrospinal fluid of adults with viral encephalitis were closely associated with prognosis (P＜0.05). 
Conclusion GFAP, CPK-BB, NSE, and S-100Bin serum and cerebrospinal fluid are highly expressed in adults with viral encephalitis and are closely correlated with the disease severity and prognosis, providing a favorable basis for the diagnosis and management of this disease. 

Key words: encephalitis, viral, cerebrospinal fluid, serum