Diagnostic Value Of T-SPOT.TB Assay For Tuberculosis Pleural Effusion

Objective To investigate the diagnostic value of T-SPOT.TB assay for tuberculosispleural effusion.Methods The peripheral blood mononuclear cells（PBMCs） and pleural effusionmononuclear cells (PEMCs) were separated from69patients. Then the early secretoryantigenic target6(ESAT-6) and culture filtered protein10were co-cultured.Then Tlymphocytes releasing interferon-γ were detected which record as spot formingcells(SFCs) with a median and interquartile range by ELISPOT assay. Sensitivity,specificity, positive predictive value, negative predictive value, positive likelihood ratio,negative likelihood ratio were also detected. The optimum cut-off points resultingfrom the best sensitivity-specificity balance in the ROC curves were constructed.Results Five of the69patients gave indeterminate ELISPOT assay results.34patientswere dignosised with tuberculosis pleural effusion, and30patients were dignosisedwith no-tuberculosis pleural effusion. The median and interquartile range of SFCs fromsESAT-6、pESAT-6、sCFP-10and pCFP-10（s represent blood，p represent plural）were22、15-27.5，94、48.75-231，20、14.25-26.25and114、47.25-245.5respectivelywith tuberculosis pleural effusion.The median and interquartile range of SFC fromsESAT-6、pESAT-6、sCFP-10and pCFP-10were3、2-5，2、1-3，3、2-4，3and1.75-4respectively with no-tuberculosis pleural effusion. The number of ESAT-6and CFP-10specific cells in the pleural fluid or peripheral blood in TB group are both higher than the number in NTB group（p＜0.05）.The number of ESAT-6and CFP-10specific cellsin the pleural fluid are higher than the number in peripheral blood in TB group（p＜0.05）,which can not be found in NTB group（p＞0.05）.The sensitivity, specificity,positive predietive value,Negative predictive value,positive likelihood ratioand negative likelihood ratio of sESAT-6，pESAT-6，sCFP-10,pCFP-10,sT-SPOT andpT-SPOT to diagnosis tuberculosis pleural effusion were85.29%、90%、90.63%、84.38%、8.53、0.16；79.41%、93.33%、93.10%、80%、11.91、0.22；91.18%、83.33%、86.11%、89.29%、5.47、0.11；91.18%、83.33%、86.11%、89.29%、5.47、0.11；88.24%、86.67%、88.24%、86.7%、6.62、0.14；91.18%、83.33%、86.11%、89.29%、5.47、0.11respectively.The ROC area,cut-off value, sensitivity and specificity were0.877、11、85.3%、90%，0.903、11、79.4%、93.3%，0.929、14.5、91.2%、83.3%and0.937、30、88.2%、90%.Conclusion The T-SPOT.TB assay could be used to detect TB infection and to assistthe diagnosis for tuberculosis pleural effusion,because of its high sensitivity andspecificity.