Comparative tests for the diagnosis of latent infection and active tuberculosis caused by Mycobacterium tuberculosis using tuberculin skin test and interferon-³ release assay (IGRA) in HIV-infected/AIDS patients

Abstract

Tuberculosis (TB) is a serious public health problem in Brazil and the most important cause of death in AIDS patients, and one of the most common opportunistic infections in this population. Among HIV-infected subjects treatment of latent infection is the only way for preventing TB and lethality reduction. In HIV-infected subjects, treatment of latent infection is the only way to prevent the occurrence of TB and reduce mortality. Until 2001, the Tuberculin Skin Test (TST) was the only one available for assessing individuals with latent tuberculosis infection (LTBI). Recently, interferon-gamma (IFN-gamma) is known as playing an important role on the T-cell immune response in patients infected with M. tuberculosis, has gained space. The IGRA (Interferon-gamma release assay) is based on the secretion of IFN-gamma by circulating T-cells upon ex vivo stimulation with specific antigens, and has shown encouraging results with the objective of assisting the diagnosis of LTBI . The main advantage of IGRA compared to TST, is its higher specificity for detection of LTBI and require only one visit to the individual implementation. However, more studies are needed to estimate the prognostic value in identifying individuals with LTBI at greatest risk of developing TB disease, especially the immune-compromised. The role of IGRA in co-infected patients (TB/HIV) has not been established. This project aims to study the behavior of a test IGRA (QuantiFERON Gold In Tube ®, Collestis, Carnegie, Australia) for the diagnosis of latent infection with M. tuberculosis and the diagnosis of TB disease in adults infected with HIV/AIDS at various stages of immunodeficiency. (AU)