Clinical Utility of Two Interferon-gamma Release Assays on Pleural Fluid for the Diagnosis of Tuberculous Pleurisy

• Published in: Tuberculosis and respiratory diseases Vol. 73; no. 3; pp. 143 - 150
• Main Authors: Kang, Ji Young, Rhee, Chin Kook, Kang, Na Hyun, Kim, Ju Sang, Yoon, Hyoung-Kyu, Song, Jeong Sup
• Format: Journal Article
• Language: English
• Published: Korea (South) The Korean Academy of Tuberculosis and Respiratory Diseases 01.09.2012; 대한결핵및호흡기학회
• Subjects: Original; 내과학; Interferon-gamma Release Tests; Tuberculosis, Pleural
• ISSN: 1738-3536; 2005-6184; 2005-6184
• DOI: 10.4046/trd.2012.73.3.143

The release of interferon-gamma (IFN-γ) by T lymphocytes increases after rechallenge with Mycobacterium tuberculosis antigen, especially, at a localized site of tuberculosis (TB) infection. We aimed to compare the clincial efficacy of two commercial IFN-γ release assays from pleural fluid for the diagnosis in tuberculous pleurisy. We performed T-SPOT.TB and QuantiFERON-TB Gold tests simultaneously on pleural fluid and peripheral blood samples from patients with pleural effusion, in South Korea, an area with intermediate TB burden. Thirty-six patients were enrolled prospectively, and tuberculous pleurisy was found in 21 patients. Both the numbers of IFN-γ secreting T cells and the concentration of IFN-γ were greater in the pleural tuberculous group, comparing with the non-tuberculous group. Moreover, in the tuberculous group, there was a significant difference in IFN-γ producing spot-forming cells using the T-SPOT.TB method between pleural fluid and peripheral blood. The receiver operating characteristic (ROC) curve, was the greatest for pleural fluid T-SPOT.TB test, followed by peripheral blood T-SPOT.TB test, peripheral blood QuantiFERON-TB Gold test, and pleural fluid QuantiFERON-TB Gold test (area under the ROC curve of 0.956, 0.890, 0.743, and 0.721, respectively). The T-SPOT.TB assay produced less indeterminate results than did QuantiFERON-TB Gold assay in both pleural fluid and peripheral blood. These findings suggest that the pleural fluid T-SPOT.TB test could be the most useful test among the IFN-γ release assays for diagnosing tuberculous pleurisy in an area with an intermediate prevalence of TB infection.