Evaluation of Quantiferon-TB Gold Plus test results before and after treatment in active tuberculosis patients

Project no. 23265 · Status: Kapanmış (Yayın bekleniyor) · 2021

Summary

ABSTRACTPURPOSE: One of the important diagnostic tests for the detection of latent tuberculosis infection (LTBI) are interferon-γ (IFN) release tests (IGRAs). In previous studies, the difference in immune response between active and LTBI was investigated, but the change in immunological responses of patients with active infection and 6 months of antituberculosis treatment was not examined. In this study, while examining the difference in immunological response between the two periods, clinical factors that may affect the test results were also investigated. It is aimed to illuminate the performance of the QFT-Plus test in the active and post-treatment period and the change in immune responses, through the obtained data.MATERIALS AND METHODS: The QuantiFERON-TB Gold Plus (QFT-Plus, QIAGEN, Germany) test is used as the IGRA test at the Ege University Medical Faculty Hospital (EUMFH), there are 4 tubes in the QFT-Plus test, nil, TB1, TB2, and mitogen. While TB1 releases IFN from CD4 cells, TB2 releases IFN from CD4 and CD8 cells. In 2019-2022, QTF-Plus test was repeated in 18 of 58 cases whose QFT-Plus test was studied during active tuberculosis infection period at EUMFH after six months of antituberculous treatment. While examining the immunological response difference between the two periods, clinical factors (age, lymphocyte count, involved organ, immunosuppression) that may affect the test results were also investigated in the study. The effect of clinical factors was analyzed with the chi-square test, and the changes in immune response (TB1-nil, TB2-nil IU/ml) in the TB1 and TB2 tubes of the QFT-Plus test in the acute period were analyzed with the T-test.RESULTS: It was observed that the sensitivity of the QFT-Plus test, TB1 and TB2 tubes decreased after the treatment compared to the active infection period, but it was not a statistically significant difference (p>0.05). The clinical factors did not make a significant difference in both periods also did not affect the test performance. The IFN response of the TB1 and TB2 tube decreased significantly between active infection and the post-treatment period. Post-treatment IFN response 1.94 IU/ml in TB1 tube [95% CI 0.77–3.11; (p=0.003)], 2 IU/ml in TB2 tube [95% CI 0.23–3.76; (p=0.029)] was found to decrease. When immunosuppressed patients were excluded from the analysis, the decrease in IFN response was observed again after treatment, but the result of the TB2 tube was not statistically significant.CONCLUSİON: It has been observed that the sensitivity of the QFT-Plus test and the IFN response in the TB1 and TB2 tubes may be decreased in patients that treated for tuberculosis infection. In addition clinical factors did not significantly affect the test performance.Keywords: Interferon gamma release tests; tuberculosis infection; tuberculosis treatment

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