title: Serial interferon-gamma release assays after rifampicin prophylaxis in a tuberculosis outbreak.
abstract: Even though some studies have reported the results of serial interferon-gamma release assays (IGRAs) during isoniazid prophylactic treatment, serial results have not been reported after rifampicin prophylaxis. A contact investigation was conducted after a tuberculosis (TB) outbreak in an accommodation facility. The tuberculin skin test (TST) and the QuantiFERON-TB Gold In-Tube (QFT-GIT) test were performed in 214 contacts with normal chest radiographs. Rifampicin prophylaxis was initiated in TST+/QFT-GIT+ subjects, and the QFT-GIT test was repeated upon completion of 4 months of rifampicin treatment. Among the 214 contacts, the TST and QFT-GIT test results were positive in 67.7% and 56.7%, respectively, and the agreement between the two tests was fair-to-good (78.3%, kappa=0.55, p<0.001). The QFT-GIT test was positive in 77% (97/126) of contacts with positive TST results. Rifampicin prophylaxis was completed in 81 subjects with good compliance. Among 74 subjects with valid serial QFT-GIT test results, IFN-gamma levels decreased in 97.3% (72/74) of the subjects and QFT-GIT test reversion (positive to negative) was achieved in 31 subjects (41.9%). Subjects without QFT-GIT test reversion had a significantly higher baseline TST induration sizes (18.3+/-4.8 vs. 14.9+/-3.4mm, p<0.01) and IFN-gamma levels (18.6+/-17.9 vs. 3.2+/-7.5IU/mL, p<0.01) than the subjects with QFT-GIT test reversion. Thus, IGRAs may be useful in evaluating the therapeutic response to rifampicin prophylaxis in TB contacts. However, considering that this was not a controlled study, a prospective controlled study is needed to determine whether rifampicin prophylaxis truly affects QFT-GIT reversion.
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Busan Paik Hospital, Inje University College of Medicine, Busan, South Korea.
authors.forename: Seung Heon
authors.initials: SH
authors.lastname: Lee
authors.forename: Woo Jin
authors.initials: WJ
authors.lastname: Lew
authors.forename: Hee Jin
authors.initials: HJ
authors.lastname: Kim
authors.forename: Hyun-Kyung
authors.initials: HK
authors.lastname: Lee
authors.forename: Young Min
authors.initials: YM
authors.lastname: Lee
authors.forename: Chong Hee
authors.initials: CH
authors.lastname: Cho
authors.forename: Eun Joo
authors.initials: EJ
authors.lastname: Lee
authors.forename: Dong Yeol
authors.initials: DY
authors.lastname: Lee
authors.forename: Sung Weon
authors.initials: SW
authors.lastname: Ryu
authors.forename: Soo Yeon
authors.initials: SY
authors.lastname: Oh
authors.forename: Sin Ok
authors.initials: SO
authors.lastname: Kim
authors.forename: Tae Sun
authors.initials: TS
authors.lastname: Shim
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000995:Antitubercular Agents / Q000627:therapeutic use*; D004196:Disease Outbreaks; D005260:Female; D006801:Humans; D007371:Interferon-gamma / Q000276:immunology*; D055985:Latent Tuberculosis / Q000175:diagnosis / Q000188:drug therapy / Q000276:immunology; D008297:Male; D008875:Middle Aged; D056910:Republic of Korea; D012293:Rifampin / Q000627:therapeutic use*; D014374:Tuberculin Test / Q000379:methods; D014397:Tuberculosis, Pulmonary / Q000175:diagnosis / Q000188:drug therapy / Q000276:immunology; D055815:Young Adult
chemical_list: D000995:Antitubercular Agents; D007371:Interferon-gamma; D012293:Rifampin