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

PLoS One. 2010 Jul 20;5(7):e11670. doi: 10.1371/journal.pone.0011670.

Abstract

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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Cell Line
  • Child
  • Female
  • Humans
  • Immunoassay / methods*
  • Interferon-gamma / metabolism
  • Interleukin-2 / metabolism*
  • Logistic Models
  • Male
  • Mycobacterium tuberculosis / immunology*
  • Mycobacterium tuberculosis / metabolism
  • Skin Tests
  • Tuberculin / metabolism
  • Tuberculosis / diagnosis*
  • Tuberculosis / immunology
  • Tuberculosis / microbiology
  • Young Adult

Substances

  • Interleukin-2
  • Tuberculin
  • Interferon-gamma