Serial interferon-gamma release assays after rifampicin prophylaxis in a tuberculosis outbreak.
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.
Lee
Seung Heon
SH
Division of Pulmonary and Critical Care Medicine, Department of Internal Medicine, Busan Paik Hospital, Inje University College of Medicine, Busan, South Korea.
Lew
Woo Jin
WJ
Kim
Hee Jin
HJ
Lee
Hyun-Kyung
HK
Lee
Young Min
YM
Cho
Chong Hee
CH
Lee
Eun Joo
EJ
Lee
Dong Yeol
DY
Ryu
Sung Weon
SW
Oh
Soo Yeon
SY
Kim
Sin Ok
SO
Shim
Tae Sun
TS
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
D000995:Antitubercular Agents; D007371:Interferon-gamma; D012293:Rifampin