Enfermedades infecciosas y microbiología clínica
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Enferm. Infecc. Microbiol. Clin. · Apr 2010
ReviewInterferon gamma release assays: principles and practice.
The last decade has witnessed significant advances in mycobacterial genomics and cellular research which have resulted in the development of two new blood tests, the enzyme-linked immunospot assay (ELISpot) (TSPOT. TB, Oxford Immunotec, Oxford, UK) and the enzyme-linked immunosorbent assay (ELISA) (QuantiFERON-TB Gold In-Tube, Cellestis, Carnegie, Australia). These tests, which are collectively known as interferon gamma release assays (IGRAs), detect latent tuberculosis infection (LTBI) by measuring interferon (IFN)-gamma release in response to antigens present in Mycobacterium tuberculosis, but not bacille Calmette-Guerin (BCG) vaccine and most nontuberculous mycobacteria. ⋯ Their high specificity means that BCG-vaccinated individuals with a false-positive TST will not receive unnecessary preventive treatment, whereas improved sensitivity in individuals with weakened cellular immunity at highest risk of progressing to active TB (for example HIV-positive individuals) enables more reliable targeted testing and treatment of these vulnerable groups. The role of IGRAs in active TB is less clear but they may be useful as adjunctive tests in the diagnostic work-up of an individual with suspected TB. Finally, recent developments and future directions in IGRA development are reviewed.