In 2016, 10.4 million people fell ill with Tuberculosis (TB), and 1.7 million died from the disease. About one-quarter of the world’s population has latent TB (LTBI), which means people have been infected by TB bacteria but are not ill with the disease and cannot transmit the disease. When a person develops active TB (ATB), the symptoms may be mild for many months, leading to delayed seeking of care and potential transmission of the bacteria to others. Without proper treatment, 45% of HIV-negative people with ATB and nearly all HIV-positive people with ATB will die.
Recent reports have indicated that basal gene expression profiles in the blood of infected patients correlate with disease activity.
- This group have identified GBP6 and BATF2 as two highly specific and sensitive markers for ATB in patients
- Peripheral blood mRNA levels of GBP6 or BATF2 can differentiate ATB from LTBI patients with TB-like symptoms with > 80% sensitivity and specificity
- Significant improvement over culture and sputum smear microscopy, which have a sensitivity of ~65%
- Can differentiate ATB from LTBI in adult and paediatric patients (TB is particularly difficult to diagnose in children)
- Can differentiate ATB from LTBI regardless of HIV status (currently available tests struggle to diagnose ATB in HIV-positive patients)
- The diagnostic performance of GBP6 and BATF2 was not improved when combined with one another but was significantly improved when combined with a Tuberculosis Skin Test (TST), suggesting that they could be used together to further improve the accuracy of TB diagnosis