Tuberculosis is a bacterial infection, and traditionally the diagnosis is confirmed with the help of sputum analysis. Emory Health Sciences' researchers have identified blood-based bio-markers in patients with active tuberculosis that could lead to new blood-based diagnostics and tools for monitoring treatment response and cure.
The research team sought to identify blood-based bio-markers in patients with active tuberculosis (ATB). The scientists hypothesized that expression of immune activation markers on Mycobacterium tuberculosis (Mtb)- specific T cells would be associated with the amount of bacteria present within an infected individual and could thus provide a gauge of Mtb, the bacterium that causes TB infection. The researchers reasoned that individuals with ATB disease would harbor higher frequencies of immune markers CD38+/HLA-DR+/Ki-67+ in their blood than those with latent Mtb infection (LTBI) or those who had cleared their infection after successful treatment.
Jyothi Rengarajan, lead researcher of the study, said, "In order to reduce the burden of TB globally, identifying and treating all TB cases is a critical priority, but accurate diagnosis of active TB disease remains challenging and methods for monitoring how well a patient responds to the six-to nine-month long, four-drug regimen of anti-TB treatment, are highly inadequate. In this study, we have identified T cell bio-markers that accurately identify ATB patients. These bio-markers have the potential to lead to new blood-based diagnostics for TB as well as provide a set of tools for monitoring treatment response and cure. The findings show that blood-based bio-markers have the potential to accurately diagnose ATB and discriminate between ATB and LTBI. We are now interested in evaluating these bio-markers in larger studies in TB-endemic areas and across a roader spectrum of Mtb infection, including extra-pulmonary TB and in HIV-infected populations. Blood-based bio-markers will be particularly useful in situations where sputum-based diagnosis of TB is more difficult. Because these bio-markers provide a gauge of Mtb load within individuals, they could also have utility as surrogate markers of treatment response and as predictors of treatment efficacy, cure and relapse in patients undergoing treatment for drug-susceptible as well as drug-resistant TB."