PLoS ONE (Jan 2010)

Potential role for IL-2 ELISpot in differentiating recent and remote infection in tuberculosis contact tracing.

  • Benjamin Krummel,
  • Alan Strassburg,
  • Martin Ernst,
  • Norbert Reiling,
  • Barbara Eker,
  • Heidrun Rath,
  • Robert Hoerster,
  • Waltraud Wappler,
  • Andrea Glaewe,
  • Volker Schoellhorn,
  • Giovanni Sotgiu,
  • Christoph Lange

DOI
https://doi.org/10.1371/journal.pone.0011670
Journal volume & issue
Vol. 5, no. 7
p. e11670

Abstract

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Interferon (IFN)-gamma release assays (IGRA) have improved tuberculosis contact tracing, but discrimination of recent from remote Mycobacterium tuberculosis contacts is not possible by IGRA alone. We present results of a tuberculosis contact investigation with a new early-secretory-antigenic-target (ESAT)-6 and culture-filtrate-protein (CFP)-10 specific interleukin (IL)-2 ELISpot in addition to ESAT-6 and CFP-10 specific IFN-gamma ELISpot and tuberculin skin testing (TST). Results of the TST, IFN-gamma ELISpot and IL-2 ELISpot were positive in 6/172 (3.4%), 7/167 (4.2%) and 6/196 (3.1%) of contacts, respectively. Close contact (> or =100 hours) to the index case increased the risk of positive results in the IFN-gamma ELISpot, TST, and IL-2 ELISpot by 40.8, 19.3, and 2.5 times, respectively. Individuals with a positive IFN-gamma ELISpot/negative IL-2 ELISpot result had a median (IQR) duration of index case exposure of 568 hours (133_1000) compared to individuals with a positive IFN-gamma ELISpot/positive IL-2 ELISpot result (median = 24 hours; 20_130; p-value = 0.047). Combination of a M. tuberculosis specific IFN-gamma ELISpot with a M. tuberculosis specific IL-2 ELISpot significantly improved the identification of individuals with the highest risk of recent M. tuberculosis infection and is a promising method that should be explored to target tuberculosis preventive chemotherapy.