ⓘ Interferon gamma release assay


ⓘ Interferon gamma release assay

Interferon-γ release assays are medical tests used in the diagnosis of some infectious diseases, especially tuberculosis. Interferon-γ release assays rely on the fact that T-lymphocytes will release IFN-γ when exposed to specific antigens. These tests are mostly developed for the field of tuberculosis diagnosis, but in theory, may be used in the diagnosis of other diseases which rely on cell-mediated immunity, e.g. cytomegalovirus and leishmaniasis. For example, in patients with cutaneous adverse drug reactions, challenge of peripheral blood lymphocytes with the drug causing the reaction produced a positive test result for half of the drugs tested.

Currently, there are two IFN-γ release techniques for the diagnosis of tuberculosis:

  • T-SPOT.TB, a form of ELISPOT, the variant of ELISA licensed in Europe, US, Japan and China.
  • QuantiFERON-TB Gold licensed in US, Europe and Japan, and.

The former test quantitates the amount of IFN-γ produced in response to esat-6 and CFP-10 antigens from Mycobacterium tuberculosis, which differ from those present in BCG and most other non-tuberculous mycobacteria. The last test determines the total number of individual effector T cells expressing IFN-γ.

Indications for the test are still disputed. He was evaluated for the diagnosis of latent tuberculosis in patients with HIV, who often have a negative Mantoux test.