Specific detection of tuberculosis infection: an interferon-gamma-based assay using new antigens.
The tuberculin skin test for immunologic diagnosis of Mycobacterium tuberculosis infection has many limitations, including being confounded by bacillus Calmette-Guérin (BCG) vaccination or exposure to nontuberculous mycobacteria. M. tuberculosis-specific antigens that are absent from BCG and most nontuberculous mycobacteria have been identified. We examined the use of two of these antigens, CFP-10 and ESAT-6, in a whole blood IFN-gamma assay as a diagnostic test for tuberculosis in BCG-vaccinated individuals. Because of the lack of an accurate standard with which to compare new tests for M. tuberculosis infection, specificity of the whole blood IFN-gamma assay was estimated on the basis of data from people with no identified risk for M. tuberculosis exposure (216 BCG-vaccinated Japanese adults) and sensitivity was estimated on the basis of data from 118 patients with culture-confirmed M. tuberculosis infection who had received less than 1 week of treatment. Using a combination of CFP-10 and ESAT-6 responses, the specificity of the test for the low-risk group was 98.1% and the sensitivity for patients with M. tuberculosis infection was 89.0%. The results demonstrate that the whole blood IFN-gamma assay using CFP-10 and ESAT-6 was highly specific and sensitive for M. tuberculosis infection and was unaffected by BCG vaccination status.
Mori
Toru
T
Research Institute of Tuberculosis, 3-1-24 Matsuyama, Kiyose, Tokyo 204-8533, Japan. tmori@jata.or.jp
Sakatani
Mitsunori
M
Yamagishi
Fumio
F
Takashima
Tetsuya
T
Kawabe
Yoshiko
Y
Nagao
Keiji
K
Shigeto
Eriko
E
Harada
Nobuyuki
N
Mitarai
Satoshi
S
Okada
Masaji
M
Suzuki
Katsuhiro
K
Inoue
Yoshikazu
Y
Tsuyuguchi
Kazunari
K
Sasaki
Yuka
Y
Mazurek
Gerald H
GH
Tsuyuguchi
Izuo
I
D000293:Adolescent; D000328:Adult; D000942:Antigens, Bacterial / Q000276:immunology*; D001500:BCG Vaccine / Q000276:immunology; D001426:Bacterial Proteins / Q000276:immunology*; D003429:Cross Reactions; D004797:Enzyme-Linked Immunosorbent Assay; D000939:Epitopes; D005260:Female; D006801:Humans; D007118:Immunoassay / Q000379:methods*; D007156:Immunologic Memory; D007371:Interferon-gamma / Q000378:metabolism; D008297:Male; D009169:Mycobacterium tuberculosis / Q000276:immunology*; D012680:Sensitivity and Specificity; D013601:T-Lymphocytes / Q000276:immunology; D014374:Tuberculin Test; D014376:Tuberculosis / Q000175:diagnosis*; D014611:Vaccination
D000942:Antigens, Bacterial; D001500:BCG Vaccine; D001426:Bacterial Proteins; C117940:CFP-10 protein, Mycobacterium tuberculosis; C093276:ESAT-6 protein, Mycobacterium tuberculosis; D000939:Epitopes; D007371:Interferon-gamma