Abstract: Objective: To detect the levels of B7-H4 protein, adenosine deaminase (ADA) and carcinoembryonic antigen (CEA) in the malignant pleural effusion associated with lung cancer (LC-MPE) and tuberculous pleural effusion (TPE), and to evaluate the values of single and combined detection of B7-H4 protein,ADA and CEA in differential diagnosis of LC-MPE and TPE. Methods: A total of 202 samples of pleural effusion(PE) from 120 LC-MPE patients(LC-MPE group) and 82 TPE patients(TPE group) were collected. The levels of ADA and CEA and B7-H4 protein in PE were detected by the enzymatic, electrochemiluminescence and ELISA methods, respectively; and the receiver operating characteristic curve(ROC curve) was used to determine the diagnostic efficiencies of the above indexes alone or in combination,such as the sensitivity,the specificity, the Yoden index(YI),and the area under ROC curve(AUC). Results: The level of ADA in PE of the patients in TPE group was higher than that in LC-MPE group (P<0.05); the levels of CEA and B7-H4 protein in PE of the patients in LC-MPE group were higher than those in TPE group (P<0.05).The ROC curve analysis results showed that the sensitivities of single detection of ADA, CEA and B7-H4 protein were 93.30%, 83.33% and 79.90%, respectively; the specificities were 86.59%, 96.34% and 72.50%, respectively; the AUC were 0.927, 0.925 and 0.836, respectively. The combined detection of the three indexes had the highest diagnostic value; the sensitivity was 93.90%, the specificity was 97.50%, the YI was 0.971, and the AUC was 0.998. Conclusion: The combined detection of levels of ADA, CEA and B7-H4 protein in PE is superior to the single evaluation of each index, which can greatly improve the differential diagnosis efficiencies of LC-MPE and TPE.

Key words: pleural effusion, adenosine deaminase, carcinoembryonic antigen, B7-H4 protein, tuberculous pleurisy