Common variable immunodeficiency: Gut bacteria tire out T-cells
- Date:
- September 15, 2014
- Source:
- The Rockefeller University Press
- Summary:
- Leaky intestines may cripple bacteria-fighting immune cells in patients with common variable immunodeficiency (CVID), a rare hereditary disease. The study may explain why these patients suffer from recurrent bacterial infections.
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Leaky intestines may cripple bacteria-fighting immune cells in patients with a rare hereditary disease, according to a study by researchers in Lausanne, Switzerland. The study, published in The Journal of Experimental Medicine, may explain why these patients suffer from recurrent bacterial infections.
Patients with a disease called common variable immunodeficiency (CVID) suffer from recurrent bacterial infections as a result of faulty immune cells. But despite these immune defects, CVID patients rarely contract viral infections. New data from Matthieu Perreau and colleagues in Lausanne now show that bacteria-fighting T cells in the blood of these patients showed signs of exhaustion (evident by their expression of an inhibitory protein called PD-1), but virus-fighting T cells were unscathed.
T cell exhaustion in the patients was associated with increased gut bacteria in the bloodstream, possibly due to the lack of protective antibodies that normally clear these wayward bugs. As a result, bacteria-specific T cells may be repetitively stimulated, a scenario known to trigger exhaustion. Indeed, the tired T cells from CVID patients could be rejuvenated by blocking PD-1. And in patients who received infusions of antibodies ("IVIG" therapy), often used to treat symptoms of CVID, PD-1 expression on T cells waned along with the levels of bacteria in the blood.
The data suggest that "immunotherapy" strategies aimed at perking up T cells -- already in use in cancer patients -- may protect CVID patients against recurrent bacterial infection.
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Materials provided by The Rockefeller University Press. Note: Content may be edited for style and length.
Journal Reference:
- Perreau, M., et al. Exhaustion of bacteria-specific CD4 T cells and microbial translocation in common variable immunodeficiency disorders. The Journal of Experimental Medicine, 2014 DOI: 10.1084/jem.20140039
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