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22 August 2018 Research Published: Infectious Diseases: Natural killers associated with latent Tuberculosis

22 Aug 2018 - 22:00

SATVI authors Associate Professor Tom Scriba, Dr Elisa Nemes, Adam Penn-Nicholson, Virginie Rozot and Fatoumatta Darboe have co-authored an article titled: "A multi-cohort study of the immune factors associated with M. tuberculosis infection outcomes" appearing in the Nature Journal.

Higher levels of natural killer cells in blood are associated with tuberculosis (TB) latency, reports a paper published online this week in Nature. The findings raise the question as to whether natural killer cells might play an active role in controlling infection with Mycobacterium tuberculosis, the TB bug.
 
TB is a bacterial disease and a leading cause of infection-related deaths globally. The majority of TB infections are latent — manifesting, without outward symptoms, in a contained state. It is estimated that a quarter of the world’s population has latent TB, although fewer than 10% of individuals with latent TB end up progressing to an active disease state. The immune factors that influence a given individual’s infection outcome, however, are poorly understood.
 
To investigate the immune state that leads to latency and how that changes if the disease progresses, researchers from the South African TB Vaccine Initiative at the University of Cape Town collaborated with Yueh-hsiu Chien and colleagues, to conduct studies of various human cohorts. They combined mass cytometry analysis with examination of gene expression datasets to identify differences in blood immune cell populations between uninfected subjects and those with latent or active TB.
 
They find that latent manifestations of TB are associated with higher numbers of natural killer cells — white blood cells that can kill certain pathogens — with enhanced anti-toxin responses in comparison to uninfected individuals. In subjects with active disease, levels of natural killer cells were diminished, but abundances returned to baseline levels when the disease was cured with antibiotic treatment. However, the findings cannot prove a causal relationship between natural killer cells and TB latency.
 
Additionally, the authors show that measurements of natural killer cell levels could be used to determine the activity level and burden of TB infection in a patient’s lungs — a finding that could help to assess disease progression and optimize treatments.

Click here to read abstract.