title: Influence of previous tuberculin skin test on serial IFN-γ release assays.
abstract: Tuberculin skin test (TST) and interferon-γ release assays (IGRAs) have been proposed for serial testing in tuberculosis. In the present study, we assessed the effect of TST on subsequent QuantiFERON-TB Gold In-Tube (QFT-GIT) results by monitoring the evolution of responses during a follow-up period of 6 weeks. One hundred and two subjects were initially tested with QFT-GIT and subsequently with TST; then the QFT-GIT was performed serially 1, 2, 4, and 6 weeks after the TST. A subgroup of 40 subjects was also assessed by older version of the QuantiFERON-TB Gold (QFT-G) assay. The results showed no significant variation in IFN-γ response over time in the tested patients, although two TST-positive subjects showed evidence of possible boosting effect. In addition, a direct comparison between the QFT-G and QFT-GIT test showed no significant differences at any time point with excellent agreement between two tests. No significant differences were seen in IFN-γ responses between BCG-unvaccinated and BCG-vaccinated patients at each time point. In conclusion, our findings indicate that TST does not influence the outcome of subsequent IGRAs testing in individuals with negative TST results, but it can boost the IFN-γ response in subjects sensitized to TB antigens and not detected by IGRA.
authors.affiliation: Dipartimento di Sanità Pubblica e Malattie Infettive, Istituto Pasteur-Fondazione Cenci-Bolognetti, Sapienza University, Piazzale Aldo Moro 1, 00185, Rome, Italy. ilariasauzullo@libero.it
authors.forename: Ilaria
authors.initials: I
authors.lastname: Sauzullo
authors.forename: Anna P
authors.initials: AP
authors.lastname: Massetti
authors.forename: Fabio
authors.initials: F
authors.lastname: Mengoni
authors.forename: Raffaella
authors.initials: R
authors.lastname: Rossi
authors.forename: Miriam
authors.initials: M
authors.lastname: Lichtner
authors.forename: Camilla
authors.initials: C
authors.lastname: Ajassa
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Vullo
authors.forename: Claudio M
authors.initials: CM
authors.lastname: Mastroianni
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D007371:Interferon-gamma / Q000378:metabolism*; D059425:Interferon-gamma Release Tests; D007558:Italy / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D009163:Mycobacterium bovis / Q000276:immunology; D009169:Mycobacterium tuberculosis / Q000276:immunology*; D011446:Prospective Studies; D014374:Tuberculin Test / Q000706:statistics & numerical data; D014376:Tuberculosis / Q000276:immunology* / Q000378:metabolism; D055815:Young Adult
chemical_list: D007371:Interferon-gamma