Thermostability of IFN-γ and IP-10 release assays for latent infection with Mycobacterium tuberculosis: A TBnet study

TY - JOUR

T1 - Thermostability of IFN-γ and IP-10 release assays for latent infection with Mycobacterium tuberculosis

T2 - A TBnet study

AU - Blauenfeldt, Thomas

AU - Wagner, Dirk

AU - Aabye, Martine

AU - Heyckendorf, Jan

AU - Lange, Berit

AU - Lange, Christoph

AU - Ernst, Martin

AU - Ravn, Pernille

AU - Duarte, Raquel

AU - Morais, Clara

AU - Hoffmann, Matthias

AU - Schoch, Otto D

AU - Dominguez, Jose

AU - Latorre, Irene

AU - Ruhwald, Morten

N1 - Copyright © 2015 Elsevier Ltd. All rights reserved.

PY - 2016/5/1

Y1 - 2016/5/1

N2 - SummaryIntroduction Interferon-γ (IFN-γ) inducible protein 10kD (IP-10) and IFN-γ release assays (IGRAs) are immunodiagnostic tests aiming to identify the presence of specific cellular immune responses, interpreted as markers for latent infection with Mycobacterium tuberculosis. Incubation at higher temperatures could affect IFN-γ and IP-10 responsiveness in order to improve the performance of IP-10 release assays and IGRAs. Aim The aim of this study was to assess the robustness of whole blood based IP-10 release assay and IGRAs and the effect of hyper-thermic incubation (39°C) on the diagnostic accuracy of IP-10 release assay and IGRAs. Results We included 65 patients with confirmed pulmonary tuberculosis and 160 healthy controls from 6 European centres collaborating in the TBnet. In patients, IP-10 responses increased 1.07 (IQR 0.90-1.36) fold and IFN-γ responses decreased 0.88 (IQR 0.57-1.02) fold, with 39°C compared to 37°C incubation temperature. At 37°C IGRA sensitivity was 85% and IP-10 sensitivity was 82%, whereas specificity was 97% for both tests (p > 0.8). These minor changes observed as a result of hyper-thermic incubation were not sufficient to impact IGRA and IP-10 release assay test performance. Conclusion The performance of IGRA and IP-10 release assays is robust despite variations in the incubation temperature between 37°C and 39°C.

AB - SummaryIntroduction Interferon-γ (IFN-γ) inducible protein 10kD (IP-10) and IFN-γ release assays (IGRAs) are immunodiagnostic tests aiming to identify the presence of specific cellular immune responses, interpreted as markers for latent infection with Mycobacterium tuberculosis. Incubation at higher temperatures could affect IFN-γ and IP-10 responsiveness in order to improve the performance of IP-10 release assays and IGRAs. Aim The aim of this study was to assess the robustness of whole blood based IP-10 release assay and IGRAs and the effect of hyper-thermic incubation (39°C) on the diagnostic accuracy of IP-10 release assay and IGRAs. Results We included 65 patients with confirmed pulmonary tuberculosis and 160 healthy controls from 6 European centres collaborating in the TBnet. In patients, IP-10 responses increased 1.07 (IQR 0.90-1.36) fold and IFN-γ responses decreased 0.88 (IQR 0.57-1.02) fold, with 39°C compared to 37°C incubation temperature. At 37°C IGRA sensitivity was 85% and IP-10 sensitivity was 82%, whereas specificity was 97% for both tests (p > 0.8). These minor changes observed as a result of hyper-thermic incubation were not sufficient to impact IGRA and IP-10 release assay test performance. Conclusion The performance of IGRA and IP-10 release assays is robust despite variations in the incubation temperature between 37°C and 39°C.

KW - Journal Article

U2 - 10.1016/j.tube.2015.04.013

DO - 10.1016/j.tube.2015.04.013

M3 - Journal article

C2 - 27156612

SN - 1472-9792

VL - 98

SP - 7

EP - 12

JO - Tuberculosis

JF - Tuberculosis

ER -