Cohort study at a tertiary care hospital. OBJECTIVE: To assess the potential use of QuantiFERON-TB Gold In-Tube (QFT-G) in monitoring clinical response to anti-tuberculosis treatment. DESIGN: We conducted a cohort study of 76 active pulmonary tuberculosis patients with serial testing by QFT-G at baseline and after 2 and 6 months of treatment. At these time points, we compared the performance of QFT-G with sputum culture status of the study subjects. RESULTS: Compared to baseline, 59 (77.6%) cases showed a decline whereas 17 (22.4%) showed persistent or stronger interferon-gamma (IFN-gamma) responses at 2 months. Using robust statistical methods, we observed that QFT-G assessment at 2 months independently and significantly predicted the likelihood of remaining sputum culture-positive at the end of the intensive phase of anti-tuberculosis treatment. A higher IFN-gamma concentration by 1 international unit (IU)/ml corresponded to a 45% (95%CI 8-97) higher likelihood of failing to convert to a negative culture, whereas a rising or persistent IFN-gamma response was associated with a 17.3 (P = 0.007) times higher likelihood of remaining culture-positive at 2 months. CONCLUSIONS: Our results suggest that QFT-G can potentially be used as a tool to monitor the efficacy of anti-tuberculosis treatment.
nt J Tuberc Lung Dis. 2008;12:1146-52.

By: Katiyar SK, Sampath A, Bihari S, Mamtani M, Kulkarni H

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