Rational use of immunodiagnostic tools for tuberculosis infection: guidelines and cost effectiveness studies.
Tuberculosis (TB) remains a public health challenge and its control requires the use efficient diagnostic tools. Mycobacterium tuberculosis (MTB) elicits a strong immune response upon infection, a phenomenon measured by the old tuberculin skin test (TST). However, this test has many limitations and a high rate of positivity in BCG-vaccinated subjects. Recent studies have identified several MTB-antigens for diagnostic use, including the ESAT-6 and CFP-10 proteins. Based on these antigens, one of the most significant developments in the diagnostic armamentarium for TB has been the assays based on IFN- determination (IGRAs). The assays stem from the principle that T-cells of infected individuals produce IFN-gamma when they re-encounter the MTB antigens in vitro and this can be measured by a conventional ELISA test. The evaluation of IGRAs in different clinical settings showed many advantages over TST. The worldwide diffusion of IGRAs has increased the knowledge on their clinical use and a number of guidelines have been devised for their application. The two-step approach (first using TST followed by IGRA for confirmation) is the most favored strategy for IGRA-use in the general population, while the use of IGRAs alone is suggested in particular clinical settings and/or patient groups. Even if these tests are still costly there are a number of cost effective advantages in the "targeted" use of IGRAs over the TST. The work we present summarises all these aspects.
Department of Internal Medicine, University of Rome "Tor Vergata", Rome, Italy. Massimo.amicosante@uniroma2.it
Massimo
M
Amicosante
Massimo
M
Ciccozzi
Roumiana
R
Markova
D000942:Antigens, Bacterial / Q000276:immunology; D003362:Cost-Benefit Analysis; D017408:Guidelines as Topic; D006801:Humans; D007159:Immunologic Tests / Q000191:economics* / Q000379:methods / Q000592:standards*; D007371:Interferon-gamma; D009169:Mycobacterium tuberculosis / Q000276:immunology*; D014376:Tuberculosis / Q000175:diagnosis* / Q000276:immunology; D014397:Tuberculosis, Pulmonary / Q000175:diagnosis / Q000276:immunology
D000942:Antigens, Bacterial; C072681:Mycobacterium tuberculosis antigens; D007371:Interferon-gamma