A preliminary study on the potential value of QuantiFERON-TB Gold Plus(QFT-Plus) in identification of latent tuberculosis infection and active tuberculosis / 中华检验医学杂志

ABSTRACT

Objective:To evaluate the potential differential diagnostic value of QuantiFERON-TB Gold Plus(QFT-Plus) in patients with active tuberculosis (ATB) and latent tuberculosis infection (LTBI) people.Methods:Case-control study. A total of 108 healthcare workers and 30 ATB patients in Xi′an Chest Hospital were tested by QFT-Plus from April to November 2019, and the demographic characteristics were analyzed.Then, flow cytometry was used to analyze the relations between the QFT-Plus TB2-TB1 and the distribution of peripheral blood T lymphocyte subsets in ATB patients with positive culture results.Finally, with 34 QFT-Plus positive volunteers as LTBI group and 30 bacteriologically confirmed ATB patients as ATB group, the QFT-Plus new lyadded antigen and its potential differential diagnostic value between LTBI and ATB groups was evaluated by using the receiver operating curve (ROC).Results:In patients with ATB,QFT-plus TB2-TB1 was positively correlated with the proportion of CD8+T cells in peripheral blood T lymphocytes( r=0.586, P=0.004), negatively correlated with the proportion of CD4+ T cells( r=-0.511, P=0.015) and the ratio of CD4/CD8 ( r=-0.520, P=0.013).The peripheral blood TB2-TB1 in the ATB patients was significantly higher than that in the LTBI group[0.47(0.12,1.17) IU/ml versus 0.01(-0.08,0.22) IU/ml, U=233.5, P<0.001]. QFT-Plus TB2-TB1 can effectively distinguish ATB from LTBI, with an area under the ROC curve of 0.771 (95 %CI=0.653-0.889, P<0.001). Conclusion:QFT-Plus specific CD8 response (TB2-TB1) has the potential value to identify ATB from LTBI people.