QuantiFERON-TB Gold Plus CD8+ T Cell Responses in Contacts with Tuberculosis Disease and Recent Infection

Strategic Insights -

Research on Mycobacterium infections, specifically tuberculosis (TB), has made significant progress in recent years. A new study published in Microbiology Spectrum has shed light on the role of CD8+ T cells in the host response to TB infection. The study found that the QuantiFERON-TB Gold Plus (QFT-Plus) assay, which replaces the QuantiFERON-TB Gold in-tube (QFT-GIT) in 2016, is more sensitive in detecting TB infection. The QFT-Plus incorporates a fourth tube (TB2 tube) that stimulates CD8+ T cells, which are involved in recognizing heavily infected cells. The research concluded that the CD8+ T cell response to TB2-TB1 interferon-gamma (IFN-g) is a potential marker for TB disease and recent infection, and could be used to identify individuals who would benefit from further investigations or TB preventive treatment.

Key Takeaways:

  • The QFT-Plus assay is more sensitive in detecting TB infection compared to the QFT-GIT assay, due to the inclusion of the TB2 tube that stimulates CD8+ T cells.
  • The CD8+ T cell response to TB2-TB1 IFN-g is significantly higher in contacts with TB disease (28.8% vs 12.6%) and stringent QFT-Plus conversion is associated with TB disease in a cohort of contacts screened under the national program.
  • The CD8+ T cell response is associated with TB disease and stringent QFT-Plus conversion, indicating its potential utility as a marker for TB disease and recent infection.
  • The study retrospectively analyzed the CD8+ responses in the QFT-Plus results of contacts screened at the Singapore TB Contact Clinic from January 2018 to October 2018.
  • The research concludes that the CD8+ T cell response is a potential marker for TB disease and recent infection, and could be used to identify individuals who would benefit from further investigations or TB preventive treatment.
  • The study was conducted by Khin Mar Kyi-Win, National Centre for Infectious Diseases, Cynthia Bin-Eng Chee, Shera Tan, and Yee-Tang Wang.

Statistics:

  • 28.8% of contacts with TB disease had TB2-TB1 IFN-g 0.6 IU/mL or higher.
  • 12.6% of contacts without TB disease had TB2-TB1 IFN-g 0.6 IU/mL or higher.
  • 91% of the cohort of contacts screened under the national program had stringent QFT-Plus conversion.
  • The study was conducted from January 2018 to October 2018.

Sources:

  • QuantiFERON-TB Gold Plus CD8+ T cell responses in contacts with tuberculosis disease and recent tuberculosis infection. Microbiology Spectrum, 2025.
  • NewsRx. Research Results from National Centre for Infectious Diseases Update Understanding of Tuberculosis (QuantiFERON-TB Gold Plus CD8+ T cell responses in contacts with tuberculosis disease and recent tuberculosis infection). TB & Outbreaks Week. November 4, 2025; p 5287.