Relationship Between Whole-Blood Interferon-Gamma Responses and the Risk of Active Tuberculosis

Tuberculosis (Edinb). 2008 May;88(3):244-8. doi: 10.1016/ Epub 2008 Feb 21.


We have analyzed the relationship between the responses to the diagnostic method for Mycobacterium tuberculosis (Mtb) infection, QuantiFERON-TB Gold (QFT-G), and the risk of developing active tuberculosis (TB). Contacts under 42 years old who were exposed to a patient with infectious pulmonary TB were tested using QFT-G during an investigation. Among 172 contacts, 111 (64.5%) were QFT-G positive. All subjects were evaluated for active TB by chest X-ray examination and, if needed, by CT scan at the time of the QFT-G test and 39 were diagnosed with active TB based on radiological abnormalities consistent with TB. Of these, 35 (89.7%) were QFT-G positive. Statistically the geometric mean of interferon-gamma (IFN-gamma) production levels of the active TB group was significantly larger than that of the latent TB infection group (p=0.013). The results of the multivariate analysis clearly showed that a combined parameter of ESAT-6 and CFP-10 significantly contributes to disease risk for the infected subjects. Our results suggest that subjects with high levels of IFN-gamma production in response to either ESAT-6 and/or CFP-10 in the QFT-G test have a higher possibility of developing active TB than QFT-G positive subjects with lower levels of IFN-gamma.

MeSH terms

  • Adolescent
  • Adult
  • Antigens, Bacterial / immunology
  • Bacterial Proteins / immunology
  • Child
  • Disease Susceptibility
  • Female
  • Humans
  • Interferon-gamma / biosynthesis*
  • Male
  • Mycobacterium tuberculosis / immunology
  • Radiography
  • Risk Factors
  • Tuberculin Test
  • Tuberculosis, Pulmonary / diagnostic imaging
  • Tuberculosis, Pulmonary / immunology*
  • Tuberculosis, Pulmonary / transmission


  • Antigens, Bacterial
  • Bacterial Proteins
  • CFP-10 protein, Mycobacterium tuberculosis
  • ESAT-6 protein, Mycobacterium tuberculosis
  • Interferon-gamma