QuantiFERON®-TB Gold In-Tube reliability for immigrants with parasitic infections in Boston, USA

<sec id="st1"> <title>SETTING</title> Accurate testing and treatment for latent tuberculous infection is necessary for tuberculosis elimination. Certain parasite infections are associated with increased tuberculin skin test positivity; species-specific effects on QuantiFERON^®-TB Gold In-Tube (QGIT) have not been described. </sec> <sec id="st2"> <title>OBJECTIVE</title> To determine whether infection with helminths or protozoa affects QGIT results. </sec> <sec id="st3"> <title>DESIGN</title> We retrospectively analyzed QGIT and parasite testing results for immigrants screened in Boston, MA, USA, from 2012 to 2017. We also prospectively measured cytokines in QGIT supernatants for a subset (n = 68) with 1) helminths, 2) Blastocystis hominis, 3) other protozoa, and 4) no parasites. </sec> <sec id="st4"> <title>RESULTS</title> Of 527 immigrants screened, 141 (26.8%) were QGIT-positive and 229 (43.4%) had parasites detected: 27/527 (5.1%) had helminths and 202/527 (38.3%) protozoa. Cytokine analysis revealed increased interleukin-10 concentrations with protozoa (P = 0.04), and non-significantly higher T-helper 2 concentrations with helminths compared with no parasites. No significant differences emerged in QGIT positivity or interferon-gamma concentrations in any group. </sec> <sec id="st5"> <title>CONCLUSION</title> Study results support the use of QGIT in parasite-endemic settings. </sec>.