Comparison of the different IGRA results obtained in HD patients.

<p>PBMC freshly isolated from whole blood of 135 HD patients were incubated 24hrs in presence of nHBHA (2 µg/ml) with 5 ng/ml IL-7, or 96hrs in presence of PPD (4 µg/ml) before measuring the corresponding IFN-γ concentrations released in the supernatant. The squares represent the IFN-γ concentrations (pg/ml) in response to PPD and nHBHA in QFT positive patients (Panel A, n = 45) and in QFT negative patients (Panel B, n = 90). Each square symbolizes a single patient, black and open squares representing patients originated from high and low incidence TB countries, respectively. Dotted lines indicate the positivity cut-off for each test. Percentages represent the proportion of results within the indicated quadrant among the total number of patients (n = 135).