Use of the QuantiFERON-TB Gold In-Tube test to monitor treatment efficacy in active pulmonary tuberculosis.
METHODS
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.


METHODS
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.
Katiyar
S K
SK
Department of Tuberculosis & Respiratory Diseases, Ganesh Shankar Vidyarthi Memorial Medical College, Kanpur, India.
Sampath
A
A
Bihari
S
S
Mamtani
M
M
Kulkarni
H
H
D000328:Adult; D000995:Antitubercular Agents / Q000008:administration & dosage; D005260:Female; D006801:Humans; D007194:India; D007371:Interferon-gamma; D016013:Likelihood Functions; D016015:Logistic Models; D008297:Male; D011379:Prognosis; D011446:Prospective Studies; D011933:Reagent Kits, Diagnostic; D012680:Sensitivity and Specificity; D016896:Treatment Outcome; D014397:Tuberculosis, Pulmonary / Q000175:diagnosis* / Q000188:drug therapy*
D000995:Antitubercular Agents; D011933:Reagent Kits, Diagnostic; D007371:Interferon-gamma