Abstract: Objective  To investigate the value of serum tumor necrosis factor-α（TNF-α）, serum amyloid A(SAA) and adenosine deaminase(ADA) in the diagnosis of EBV-related infectious mononucleosis(IM) in children. 
Methods  A total of 201 children with EBV-related IM (infection group) and 200 healthy children (control group) were selected. The serum levels of TNF-α, SAA and ADA were measured, and the correlation between TNF-α, SAA, ADA and blood routine, biochemical indexes, heteromorphic lymphocyte, epstein-barrvirus deoxyribonucleic acid(EBV-DNA) copy number in EBV-related IM of children was analyzed. Receiver operator characteristics curve (ROC) was used to analyze the value of TNF-α, SAA and ADA in the diagnosis of EBV-related IM. 
Results  The serum levels of TNF-α, SAA and ADA in the infection group were higher than those in the control group(P＜0.05). The levels of TNF-α, SAA and ADA were positively correlated with lymphocytes, heteromorphic lymphocyte, EBV-DNA copy number and ALT(P＜0.05). ROC analysis showed that the area under the ROC(AUC) of TNF-α, SAA and ADA in the diagnosis of EBV-related IM was 0.752, 0.787, 0.788 and 0.931, respectively; the sensitivity was 70.65%, 77.61%, 76.12% and 92.04%, respectively, and the specificity was 76.50%, 82.00%, 84.50% and 96.00%, respectively. 
Conclusion  The serum levels of TNF-α, SAA and ADA in EBV-related IM children are significantly higher, which are closely related to the levels of heteromorphic lymphocyte, EBV-DNA copy number and liver function. Combined detection of TNF-α, SAA and ADA can improve the accuracy of EBV-related IM diagnosis.

Key words: infectious mononucleosis, TNF-α, SAA, ADA