Wednesday, February 6, 2013
Stem Cells: Safe Haven For TB
Mycobacterium tuberculosis (TB) hides out in stem cells deep within bone tissue, where it avoids detection from the immune system and drugs, according to a study published last week (January 30) in Science Translational Medicine.
Ninety percent of TB infections are cleared by the body’s immune defenses or by taking anti-TB medication. In the remaining 10 percent of cases, however, TB persists as a dormant, non-replicating infection. Though latent TB infections do not cause symptoms, they can reactivate after years of hiding. An estimated one-third of the global population has latent TB, which accounts for 1.7 million deaths per year—more than any other bacterial pathogen on the planet.
During the early stages of the disease, active TB bacteria replicate inside human macrophages and dendritic cells. But there is no evidence these cells harbor dormant TB, and the location of the latent reservoir has remained a mystery.
The original paper is in Science Translational medicine this week: CD271+ Bone Marrow Mesenchymal Stem Cells May Provide a Niche for Dormant Mycobacterium tuberculosis.