Clinical Application And Its Influencing Factors Of T-SPOT.TB For Tuberculous Pleurisy

Background Tuberculous pleurisy is the most common cause of pleural effusion with a high incidence in extrapulmonary TB,secondly only to the lymphatic tuberculosis.Mycobacterium smear and culture of tuberculosis pleural effusion are the gold standard for diagnosis of tuberculous pleurisy.However,the positive rate of pleural effusion TB smear and culture is low,and some patients do not want to accept thoracoscopy pleural biopsy because it is an invasive examination.The diagnosis of tuberculous pleurisy mainly depends on the medical history?clinical characteristics?imaging examination,pleural effusion routine biochemical and the therapeutic effect observed.The diagnosis rate is very low,easily to misdiagnosis,causing serious consequence.Therefore we need a new specific means,help us diagnosis of tuberculous pleurisy.In recent years,with the development of modern technology,T-SPOT.TB is widely used in the auxiliary diagnosis of tuberculosis(TB).T-SPOT.TB is based on enzyme-linked immunospots assay(ELISPOT)technology.The technical principles of T-SPOT.TB is interferon gamma release assays(IGRA).At home and abroad,there are many reports about on T-SPOT.TB.But these studies mainly focus on pulmonary tuberculosis,not extrapulmonary tuberculosis.Especially the value of the diagnosis of tuberculous pleurisy needs further researched.we conducted the experiment and research the clinical value and its influencing factors of T-SPOT.TB for tuberculous pleural effusion.Purpose To explore the value of T-SPOT.TB test in diagnosis of tuberculous pleurisy.To investigate the risk factor for false-negative and false-positive T-SPOT.TB assay results in patients with tuberculous pleural effusion.Method The 180 patients who was exudative pleural effusions in hospital from Jan.2013 to Dec.2015 were selected for the retrospective study.According to the diagnosis standard,the patients were divided into the tuberculous pleurisy group and non-tuberculous pleurisy group.The positive rate ? sensitivity ? specificity of T-SPOT.TB?ADA and TB-AB were calculated and compared to explore the value of T-SPOT.TB test in diagnosis of tuberculous pleurisy.To investigate the risk factor for false-negative and false-positive T-SPOT.TB assay results in patients with tuberculous pleural effusion through the logistic regression analysis.By the Mann-Whitney U and Kruskal Wallis test,the difference of the spot forming cells were compared.P<0.05 was considered to be statistically significant.Results 1.The methods of T-SPOT.TB?ADA and TB-AB to tuberculous pleurisy of positive rate(82.24% ? 65.42% ? 61.68%)was significantly higher than that of non-tuberculous pleurisy group(27.40%?43.84%?46.58%),the differences were statistically significant(P<0.05).The sensitivity of T-SPOT.TB(82.24%)was a statistically significant difference compared with ADA(65.42%)and TB-AB(61.68%),the differences were statistically significant(P<0.05).The specificity of T-SPOT.TB (72.60%)was a statistically significant difference compared with ADA(56.16%)and TB-AB(53.42%),the differences were statistically significant(P<0.05).2.Univariate analysis showed that immunocompromised patients were not significantly associated with false negative T-SPOT.TB results(P>0.05).Age and BMI were significantly associated with false negative T-SPOT.TB results(P<0.05).However,multivariate logistic regression analysis revealed that older age [odds radio(OR)4.537,P=0.016] and BMI over 25kg/m2 [odds radio(OR)5.713,P=0.007] were risk factors for false-negative T-SPOT.TB test results.3.Univariate analysis showed that history of tuberculosis(P<0.05)was significantly associated with false positive T-SPOT.TB results.However,multivariate logistic regression analysis revealed that history of TB [odds radio(OR)5.296,P=0.013 ] was independent risk factors for false positive T-SPOT.TB test results.4.The ESAT-6 SFCs in the elderly patients were significantly lower than in the younger patients(U=551,P<0.001).The CFP-6 SFCs in the elderly patients were significantly lower than in the younger patients(U=510,P <0.001).In the tuberculous pleurisy group,the ESAT-6 SFCs of BMI<18.5 kg/m?BMI18.5-25kg/m2 and BMI ? 25kg/m2 were 50(29,79)/2.5×105PBMCs?57(43,65)/2.5×105PBMCs?19(4,34)/2.5 × 105 PBMCs,the differences were statistically significant(H=22.15,P<0.001).Further,the ESAT-6 SFCs of BMI?25kg/m2 had significantly lower numbers of SFCs than those with BMI18.5-25 kg/m2(P<0.001).The CFP-6 SFCs of BMI<18.5 kg/m2 ?BMI18.5-25kg/m2 and BMI?25kg/m2 were 52(41,70)/2.5×105PBMCs?48(25,73)/ 2.5 ×105PBMCs?17(4,32)/2.5×105PBMCs,the differences were statistically significant(H=26.23,P<0.001).Further,the CFP-6 SFCs of BMI?25kg/m2 had significantly lower numbers of SFCs than those with BMI 18.5-25 kg/m2(P<0.001).The ESAT-6 SFCs of patients with a history of tuberculosis had significantly higher numbers of SFCs than patients with no history of tuberculosisthose(U=220,P=0.027).The CFP-6 SFCs of patients with a history of tuberculosis had significantly higher numbers of SFCs than patients with no history of tuberculosisthose(U=198.5,P=0.011).Conclusion1.The specificity and sensitivity of T-SPOT.TB assay were significantly better than ADA?TB-AB and could be used to assist the diagnosis for tuberculosis pleural effusion.2.T-SPOT.TB assay has satisfactory sensitivity and an important clinical value in the diagnosis of tuberculous pleurisy in immunocompromised patients.3.Older age and BMI ?25kg/m2 were risk factors for false-negative T-SPOT.TB test results.When the T-SPOT.TB of elderly and BMI?25kg/m2 patients with suspected tuberculosis was negative,we had to consider the possibility for false negatives.4.History of TB was risk factors for false-positive T-SPOT.TB test results.If a patients had a history of tuberculosis when T-SPOT.TB was positive,not to blindly diagnosis of tuberculosis.