BMC Infectious Diseases (Sep 2024)

The impact of an oral glucose load on IFN-γ-release in persons infected with Mycobacterium tuberculosis

  • Hans Johan Niklas Lorentsson,
  • Christina Reinholdt Clausen,
  • Daniel Faurholt-Jepsen,
  • Katrine Bagge Hansen,
  • Christian Ritz,
  • Sidse Graff Jensen,
  • Erik Michael Rasmussen,
  • Anja Jørgensen,
  • Troels Lillebaek,
  • Filip Knop,
  • Pernille Ravn

DOI
https://doi.org/10.1186/s12879-024-09920-x
Journal volume & issue
Vol. 24, no. 1
pp. 1 – 7

Abstract

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Abstract Background and objective To diagnose tuberculosis infection (TBI), whole blood is incubated with M.tuberculosis (Mtb)-specific peptides and the release of interferon-γ (IFN-γ) is measured in IFN-γ-release assays (IGRAs). Hyperglycaemia and fluctuations in blood glucose may modulate IFN-γ-release. Here, we investigated if glucose intake affects IFN-γ-release or IGRA results in IGRAs taken during an oral glucose tolerance test (OGTT). Methods Persons with TB disease (TB) or TBI underwent a standard 75-g OGTT at the start and end of treatment for TB or TBI. Blood for the IGRA QuantiFERON-TB Gold Plus (QFT) containing Mtb-specific tubes (TB1 and TB2), a non-specific mitogen tube (MIT) and an empty control tube (NIL) was drawn at sample-timepoints -15 (baseline), 60, 90, 120 and 240 min during the OGTT. Blood glucose was measured in parallel at all timepoints. IFN-γ-release (after subtraction of NIL) at each timepoint was compared with baseline using linear-mixed-model analysis. Results Twenty-four OGTTs from 14 participants were included in the final analysis. Compared to baseline, IFN-γ-release was increased at sample-timepoint 240 min for TB1; geometric mean (95% confidence interval) 3.0 (1.5–6.2) vs 2.5 (1.4–4.4) IU/mL (p = 0.047), and MIT; 182.6 (103.3–322.9) vs 146.0 (84.0–254.1) IU/mL (p = 0.002). Plasma glucose levels were not associated with IFN-γ-release and the QFT test results were unaffected by the OGTT. Conclusion Ingestion of glucose after a 10-h fast was associated with increased IFN-γ-release after 240 min in the MIT tube. However, there was no association between plasma glucose levels at the QFT sampling timepoint and IFN-γ-release. Furthermore, the QFT test results were not affected by glucose intake. The overall effect of an OGTT and prevailing plasma glucose levels on IFN-γ-release in IGRAs seem limited. Trial registration Trial registration ID: NCT04830462 ( https://clinicaltrials.gov/study/NCT04830462 ). Registration date: 05-Apr-2021.

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