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CDC HIV/AIDS/Viral Hepatitis/STD/TB Prevention News Update
UNITED STATES: Vitamin D Activates Immune Response to TB: Study

October 26, 2011
Agence France Presse (10.12.11) - Wednesday, October 26, 2011

While researchers have long known that vitamin D is involved in the body's response to TB, a new study shows it must be present at sufficient levels to trigger the immune response.

"Over the centuries, vitamin D has intrinsically been used to treat tuberculosis," said lead author Mario Fabri. "Sanatoriums dedicated to tuberculosis patients were traditionally placed in sunny locations that seemed to help patients, but no one knew why this worked." "Our findings suggest that increasing vitamin D levels through supplementation may improve the immune response to infections such as tuberculosis," said Fabri, who conducted the research while at the University of California-Los Angeles, and who now is at the Department of Dermatology at the University of Cologne, Germany.

Previously, the same research team showed that vitamin D plays an important role in the production of cathelicidin, a molecule that helps the innate immune system kill TB bacteria.

The new study shows that vitamin D is needed for the T-cells in the adaptive immune system to produce the protein interferon, which directs cells to attack the bacteria.

The finding could bolster TB treatment efforts in settings like Africa, as dark-skinned people are more likely to be deficient in vitamin D. This is because dark skin contains more melanin, which shields the body from ultraviolet rays and reduces vitamin D production.

"At a time when drug-resistant forms of tuberculosis are emerging, understanding how to enhance natural innate and acquired immunity through vitamin D may be very helpful," said Barry Bloom, former dean of faculty at the Harvard School of Public Health and a study co-author.

The report, "Vitamin D Is Required for IFN-gamma-Mediated Antimicrobial Activity of Human Macrophages," was published in Science Translational Medicine (10.12.11;3(104):104ra102).