IFNgamma and antibody responses among French nurses during a tuberculosis contact tracing investigation

Pathol Biol (Paris). 2009 May;57(3):e49-53. doi: 10.1016/j.patbio.2008.02.010. Epub 2008 Apr 18.


Study: A comparative study which compared PPD skin testing inserted according to the French Society of Pneumology's recommendations and interferon gamma release assay (IGRA) (QuantiFERON((R)) TB Gold In-tube, QF-TB-IT, Cellestis, Carnegie, Australia) was performed during a tuberculosis contact investigation in our hospital.

Patients: Nineteen French health-care workers (HCWs) volunteered to participate. All of the HCW enrolled were BCG vaccinated and had a normal chest X-ray at entry.

Results: Among the HCW, 68.4% were TST positive. By comparison, only 31.6% had a positive QF-TB-IT result. We took advantage of the negative tube and the corresponding plasma for antibody detection by ELISA. None were ELISA positive. Fourteen HCWs were followed up. None of the HCWs accepted a course of antiTB chemoprophylaxis. Despite the difficulty in establishing a trend in kinetics, we saw the complexity of interpretation of a dynamic T-cell response after contact with an index case.

Conclusion: This initial and first French picture provides us with the observation that only 44% of TST-positive HCW were IGRA positive, and the IGRA test allowed the detection of LTBI in two TST negative HCWs.

MeSH terms

  • Adult
  • Antibodies / blood*
  • Antibody Formation
  • BCG Vaccine / administration & dosage
  • Contact Tracing / methods*
  • Enzyme-Linked Immunosorbent Assay
  • Female
  • France
  • Humans
  • Interferon-gamma / immunology*
  • Male
  • Middle Aged
  • Mycobacterium tuberculosis / immunology*
  • Nurses*
  • Radiography, Thoracic
  • Risk Factors
  • Sensitivity and Specificity
  • Tuberculin Test
  • Tuberculosis / diagnosis
  • Tuberculosis / epidemiology
  • Tuberculosis / immunology*
  • Young Adult


  • Antibodies
  • BCG Vaccine
  • Interferon-gamma