Confronto di metodologie per l'identificazione della tubercolosi latente e attiva

Tuberculosis (TB), together with HIV and Malaria, represents one of the three infectious diseases world-wide. The World Health Organization (WHO) estimated that one third of the world’s population is infected with Mtb. Only 10%, of the exposed individuals, will develop active tuberculosis disease within 2 years post-exposure, while the remaining 90% of infected subjects contain infection for the duration of their lifetime. Existing diagnostic tools and therapeutic interventions for TB are suboptimal. Thus, new vaccines, immunotherapeutic interventions and new diagnostic tools, that are able to discriminate individuals with LTBI from those with active TB disease, are required to facilitate TB control efforts. The Tuberculin skin test (TST) is one of the few tests that have been used for about 100 years for the diagnosis of Mtb infection. However, the TST also has limitations such as: the reduced sensitivity and specificity and the inability to distinguish latently infected individuals from patients with active TB. Due to the limitations of TST, new in- vitro assays have been developed. These assays measure interferon-γ (IFN-γ) production upon Mtb specific antigen stimulation (IGRAs) and they are more sensitive and specific than TST. However, these assays do not discriminate between active TB and LTBI. Therefore, a possible contribution to discriminate these different TB stages could be envisaged in a more accurate definition of the immunological response of Mtb infection to understand which components of the host immune response or which tubercular antigens could be used to discriminate between two infection stages. It is very important as it could allow to develop new diagnostic tools, resulting in greater control of TB.