Recent research has found that sufficient vitamin D levels may be required in order for a specific protein to be able to defend against tuberculosis bacteria.
Tuberculosis (TB) is an infectious disease caused by a bacteria that mainly infects the lungs. TB can be spread through the air when an infected person coughs or sneezes.
TB can be either dormant or active. Dormant TB is when a person becomes infected with the bacteria, but might not become sick. TB becomes active when the bacteria begins to grow and cannot be stopped by the immune system. People with active TB often do get sick and can spread the bacteria to other people.
Historically, sun therapy was used to help treat TB. Doctors would have patients go under ultraviolet-B radiation, which would help cure the disease. Because ultraviolet-B wavelengths from the sun are responsible for vitamin D production in human skin, researchers think that vitamin D may play a role.
Now, researchers from University of California, Los Angeles discovered that a specific protein called interleukin-32 (IL-32), plays a key role in preventing dormant TB from becoming active. IL-32 is a protein that initiates inflammation to help fight off invasive bacteria.
“Until now, there had been no way to predict, based on biological factors, why latently infected individuals do not develop active tuberculosis,” said lead researcher Dr. Dennis Montoya.
To discover the significance of this protein, the researchers looked at genes from immune cells previously associated with killing the TB bacteria in patients with dormant TB.
They found that people were more likely to have dormant TB if they had higher levels of IL-32, but that IL-32 was only able to destroy the TB-causing bacteria if the patient also had sufficient levels of vitamin D.
“When vitamin D levels were low, IL-32 was not able to kill the bacteria,” stated Dr. Robert Modlin, the study’s senior researcher.
“However, if we simulated the effect of supplementing individuals by adding vitamin D to the culture of the activated immune cells that had low vitamin D levels, IL-32 regained its ability to kill. Our findings suggest that raising standard for daily intake of vitamin D could help protect against a TB pandemic.”