Interferon gamma release assay (IGRA)

This entry does not describe a classical molecular target such as a receptor or enzyme, but refers instead to a functional immune assay (“interferon gamma release assay”) used to detect infection with Mycobacterium tuberculosis. The IGRA measures release of interferon gamma (IFN-γ) by activated T lymphocytes in response to in vitro stimulation with specific M. tuberculosis antigens (typically ESAT-6 and CFP-10), distinguishing infection with M. tuberculosis from previous vaccination with BCG or most other non-tuberculous mycobacteria. The amount or frequency of released IFN-γ serves as a biomarker for immunological sensitization to TB. The assay itself is not a biological molecule, nor a pharmacological target, but rather a tool for tuberculosis diagnosis; its performance can be affected by immune competence, prior BCG vaccination, and cross-reactivity with select environmental mycobacteria. Results do not distinguish latent from active TB and, while IFN-γ is critical for immune defense against TB, the test does not directly relate to targeting a druggable molecule in therapy.

Other names

Interferon-γ release assayIFN-gamma release assayIGRAQuantiFERON-TB Gold PlusT-SPOT.TB