Novel interferon-gamma assays for diagnosing tuberculosis in young children in India

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International Journal of Tuberculosis and Lung Disease
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The tuberculin skin test (TST) and interferon-gamma release assays (IGRAs) are used as supportive evidence to diagnose active tuberculosis (TB). Novel IGRAs could improve diagnosis, but data are lacking in young children.


Children (age 5 years or younger) with suspected TB were prospectively screened at a tertiary hospital in Pune, India; the children underwent TST, and standard (early secretory antigenic target 6 and culture filtrate protein 10) and enhanced (five additional novel antigens) enzyme-linked immunospot (ELISpot) assays.


Of 313 children (median age 30 months) enrolled, 92% had received bacille Calmette-Guérin vaccination, 53% were malnourished and 9% were coinfected with the human immunodeficiency virus (HIV); 48 (15%) had TB, 128 (41%) did not, and TB could not be ruled out in 137 (44%). The sensitivity of enhanced (45%) and standard (42%) ELISpot assays for diagnosing TB was better than that of TST (20%) (P less than or equal to 0.03); however, enhanced ELISpot was not more sensitive than the standard ELISpot assay (P = 0.50). The specificity of enhanced ELISpot, standard ELISpot and TST was respectively 82% (95%CI 74-89), 88% (95%CI 81-94) and 98% (95%CI 93-100). Rv3879c and Rv3615c, previously reported to be promising antigens, failed to improve the diagnostic performance of the ELISpot assay.


The TST and the standard and novel ELISpot assays performed poorly in diagnosing active TB among young children in India

Shaikh N, Gupte A, Dharmshale S, Pokkali S, Thakar M, Upadhye VJ, Ordonez AA, Kinikar A, Gupte N, Mave V, Kagal A, Gupta A, Lalvani A, Paranjpe R, Bharadwaj R, Jain SK. Novel interferon-gamma assays for diagnosing tuberculosis in young children in India. Int J Tuberc Lung Dis. 2017;21(4):412–419. PMID: 28284256
  • National AIDS Research Institute, Pune, India
  • Johns Hopkins Bloomberg School of Public Health, Baltimore, MD
  • Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD
  • Byramjee Jeejeebhoy Government Medical College, Pune, India
  • Department of Pediatrics and Center for Tuberculosis Research, Johns Hopkins University School of Medicine, Baltimore, MD
  • Imperial College, London, UK