Assessment of an Interferon-gamma release assay for the diagnosis of latent tuberculosis infection in haemodialysis patient.

Abstract

The accurate diagnosis of latent tuberculosis infection (LTBI) in haemodialysis patients remains elusive. Impaired immune function associated with chronic kidney failure causes a high number of anergic tuberculin skin tests (TST). Interferon-gamma (INF-gamma) release assays (IGRAs) measuring the INF-gamma secretion of tuberculosis specific T-cells have several advantages over the TST but their significance in dialysis patients is currently uncertain. This study examines the test-performances of the QuantiFERON Gold InTube (QFT-GIT) in a cohort of 39 haemodialysis (HD) patients and 52 healthy individuals. INF-gamma secretion in HD patients was significantly lower than in healthy controls, however, mitogen-anergic QFT-GIT results were only found in 2.5% of HD-patients. INF-gamma secretion was independent of duration of HD treatment, dialysis quality and nutritional status. The QFT-GIT showed a closer association with TB risk factors as a proxy for past exposure to TB than the TST. We conclude that the QFT-GIT is a valid alternative to the TST. Together with the survey of TB risk factors, it may help to diagnose LTBI more accurately in HD-patients.