title: Characteristics of IFN-γ responses in IGRA among pulmonary TB suspects in a TB-endemic area.
abstract: Although the diagnostic value of interferon-γ (IFN-γ) release assays for active tuberculosis (TB) is limited, the characteristic of non-TB-specific IFN-γ responses among TB suspects deserves further evaluation. We enrolled clinically suspected pulmonary TB (PTB) patients, and QuantiFERON-TB Gold In-Tube (QFT-GIT) was performed. The characteristics of IFN-γ responses were analyzed. Among 392 patients, active PTB patients had stronger IFN-γ responses to TB antigen (TBAg-Nil, P < 0.001) and lower responses to mitogen (Mitogen-Nil, P < 0.001). Lower body mass index (P = 0.001), without bacille Calmette-Guerin vaccination (P = 0.026), and active PTB (P = 0.011) were independent factors associated with lower non-TB-specific IFN-γ responses. Among TB suspects with higher TBAg-Nil (>1.02 U/mL) and lower Mitogen-Nil (<5.5 U/mL), 84.3% were active PTB cases. Among TB suspects with lower TBAg-Nil and higher Mitogen-Nil, only 4.7% were active PTB. The present study suggested that the possibilities of active PTB should be carefully excluded in TB suspects with stronger TB-specific and lower non-TB-specific IFN-γ responses in QFT-GIT.
authors.affiliation: Department of Chest Medicine, Taipei Veterans General Hospital, Taipei 112, Taiwan R.O.C.
authors.forename: Jia-Yih
authors.initials: JY
authors.lastname: Feng
authors.forename: Shiang-Fen
authors.initials: SF
authors.lastname: Huang
authors.forename: Ming-Che
authors.initials: MC
authors.lastname: Lee
authors.forename: Wen-Ying
authors.initials: WY
authors.lastname: Ting
authors.forename: Yu-Chun
authors.initials: YC
authors.lastname: Chen
authors.forename: Yung-Yang
authors.initials: YY
authors.lastname: Lin
authors.forename: Yu-Chin
authors.initials: YC
authors.lastname: Lee
authors.forename: Wei-Juin
authors.initials: WJ
authors.lastname: Su
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019353:Endemic Diseases; D005260:Female; D006801:Humans; D007371:Interferon-gamma / Q000032:analysis*; D059425:Interferon-gamma Release Tests / Q000379:methods*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D014376:Tuberculosis / Q000175:diagnosis* / Q000453:epidemiology* / Q000276:immunology
chemical_list: D007371:Interferon-gamma
keywords: Active pulmonary tuberculosis; IFN-γ; IGRA; QFT-GIT; TB suspects