title: Limited usefulness of QuantiFERON-TB Gold In-Tube for monitoring anti-tuberculosis therapy.
abstract: The usefulness of IFN-gamma release assays to monitor the efficacy of anti-tuberculosis (TB) treatment is controversial. Sixty patients affected by culture-confirmed pulmonary TB (M = 36; mean age: 39.2 yr; Italians = 28) were serially tested in a low prevalence setting by means of QuantiFERON-TB GOLD In-Tube (QFT-IT) at baseline and after a successful six-month therapy regimen (T6). A sub-group of 40 cases was also tested at 1 and 3 months. Overall, 88.3% of patients scored a QFT-IT positive result at baseline, with the higher proportion of TB-specific IFN-gamma responses in foreign-born patients (p = 0.04). TB-specific responses were highly variable over time, the within-person variability being correlated with baseline IFN-gamma levels (r = 0.731; p < 0.001). Overall, 61.6% of cases still tested QFT-IT positive at the completion of therapy. Average IFN-gamma levels increased over time, being persistently significantly higher in Italian patients than in foreign-born cases both at baseline (p = 0.03) and at T6 (p = 0.02). Reversion mainly occurred in patients (26.6%) with baseline IFN-gamma levels close to the conventional cut-off value. No indeterminate results were recorded at any study time point. In conclusion, QFT-IT adds no significant information to clinicians for treatment monitoring when applied in routine clinical practice in a low prevalence setting. Kinetics of T cell responses upon TB treatment and reversion (and conversion) thresholds need to be addressed. Diversity of IFN-gamma responses among patients of different geographic origin is an issue to be investigated further.
authors.affiliation: Dipartimento di Medicina Clinica e Sperimentale, Sezione di Malattie dell'Apparato Respiratorio, Università Federico II, via S. Pansini 5, Naples, Italy. marialuisa.bocchino@unina.it
authors.forename: Marialuisa
authors.initials: M
authors.lastname: Bocchino
authors.forename: Patrizia
authors.initials: P
authors.lastname: Chairadonna
authors.forename: Alessandro
authors.initials: A
authors.lastname: Matarese
authors.forename: Dario
authors.initials: D
authors.lastname: Bruzzese
authors.forename: Mariella
authors.initials: M
authors.lastname: Salvatores
authors.forename: Mirella
authors.initials: M
authors.lastname: Tronci
authors.forename: Emilio
authors.initials: E
authors.lastname: Moscariello
authors.forename: Domenico
authors.initials: D
authors.lastname: Galati
authors.forename: Mario G
authors.initials: MG
authors.lastname: Alma
authors.forename: Alessandro
authors.initials: A
authors.lastname: Sanduzzi
authors.forename: Alfonso M
authors.initials: AM
authors.lastname: Altieri
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000553:Ambulatory Care; D000995:Antitubercular Agents / Q000627:therapeutic use*; D016903:Drug Monitoring / Q000379:methods*; D005260:Female; D006046:Gold / Q000627:therapeutic use*; D006801:Humans; D007371:Interferon-gamma / Q000378:metabolism*; D007558:Italy; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D016896:Treatment Outcome; D014397:Tuberculosis, Pulmonary / Q000188:drug therapy* / Q000378:metabolism; D055815:Young Adult
chemical_list: D000995:Antitubercular Agents; D006046:Gold; D007371:Interferon-gamma