Performance of whole blood IFN-gamma test for tuberculosis diagnosis based on PPD or the specific antigens ESAT-6 and CFP-10.
OBJECTIVE
To evaluate the QuantiFERON-TB test in BCG-vaccinated, non-BCG-vaccinated and tuberculosis (TB) patient donor groups, and to compare its diagnostic performance with that of a blood test based on the Mycobacterium tuberculosis specific antigens ESAT-6 and CFP-10.


METHODS
Analysis of the IFN-gamma responses of whole blood cells from BCG-vaccinated or non-BCG-vaccinated donors or patients with tuberculosis, stimulated with PPD, ESAT-6 or CFP-10 antigens, and evaluation of the specificity and sensitivity of the test.


RESULTS
None of the non-vaccinated donors showed positive responses to M. tuberculosis-PPD, ESAT-6 or CFP-10. In BCG-vaccinated donors, 9/19 (47%) donors responded to the QuantiFERON-TB test based on M. tuberculosis-PPD, whereas 2/19 (10.5%) responded to either ESAT-6 or CFP-10. Comparable levels of sensitivity were obtained with the QuantiFERON-TB test based on M. tuberculosis-PPD (79%) and ESAT-6 or CFP-10 antigens (72%).


CONCLUSIONS
Our results demonstrate that the whole blood test based on M. tuberculosis-PPD did not efficiently distinguish BCG-vaccinated donors from individuals with disease due to M. tuberculosis. The introduction of new recombinant antigens specific for M. tuberculosis, such as ESAT-6 or CFP-10, should increase the specificity of the whole blood test and enable discrimination between TB infection, atypical mycobacterial reactivity and reactivity due to BCG vaccination. Such a test would provide a quantum improvement over the current practice of using the tuberculin skin test for TB control and elimination.
Brock
I
I
Department of Tuberculosis Immunology, Statens Serum Institute, Copenhagen, Denmark.
Munk
M E
ME
Kok-Jensen
A
A
Andersen
P
P
D000328:Adult; D000942:Antigens, Bacterial; D001500:BCG Vaccine; D001426:Bacterial Proteins; D015415:Biomarkers; D006801:Humans; D007371:Interferon-gamma / Q000097:blood*; D012680:Sensitivity and Specificity; D014373:Tuberculin; D014376:Tuberculosis / Q000175:diagnosis*
D000942:Antigens, Bacterial; D001500:BCG Vaccine; D001426:Bacterial Proteins; D015415:Biomarkers; C117940:CFP-10 protein, Mycobacterium tuberculosis; C093276:ESAT-6 protein, Mycobacterium tuberculosis; D014373:Tuberculin; D007371:Interferon-gamma