Via practica 3–4/2013

Latent tuberculosis infection and biological treatment

Latent (subclinical) tuberculosis infection means tuberculosis mycobacteria harbor in the organism, but do not cause disease. Only about 10-15% of latently infected persons actually become ill with active tuberculosis. The transition to active disease is influenced by circumstances which weaken the immune system, especially in the field of cellular immunity. This problem took on added importance in the present, when there is increase in number of patients treated with anti-TNF-α drugs. These patients are extremely susceptible to tuberculous disease. Latent tuberculosis infection is not diagnosed by conventional diagnostic methods. In the past it was used only for diagnostic tuberculin skin test. Currently we have available 2 immunoassays – IGRA (Interferon Gamma Release Assay), which have much higher sensitivity and specificity and they rule out false positives due to BCG vaccination, which may occur in the tuberculin skin test.

Keywords: latent tuberculosis infection, biological treatment, IGRA tests.