Almost a century old, the BCG vaccine against tuberculosis is now raising hope regarding the Covid-19 epidemic. Researchers are currently conducting a trial to verify its interest before a possible future application. But how could this vaccine cure Covid-19 patients?
With about 27,000 deaths , France is one of the countries most affected by the Covid-19 pandemic. However, among the researches of treatment we find the BCG (Vaccine bilié of Calmette and Guérin). Discovered in 1921, the latter is a vaccine against tuberculosis . According to a study published in the journal Cell Stem Cell on May 7, 2020 and piloted by Michael Sieweke of the Marseille-Luminy Immunology Center (CIML), the BCG vaccine could be useful against Covid-19.
This regulates the inflammatory reaction and activates blood stem cells producing immune cells as well as other blood cells in the body. This is about hematopoietic stem cells (HSC), playing an important role in infection. Moreover, these would be ready in case of a new infection!
You should know that HSCs are found in the bone marrow and are used to make everything that makes up the blood, including immune cells. However, until today, it was thought that these cells were incapable of reacting to external stimuli such as infections. But the study leaders discovered that in the event of an infection, HSCs trigger an increase in the production of immune cells . And in the event of a second infection, the production becomes faster and more important than in the first.
Not only do HSCs boost the immune system, but they also store traces of the first infection . By "memory", we must understand epigenetic modifications or even DNA marking. In addition, the researchers observed a fairly weak response to inflammatory signals.
This is a very interesting element since the organism infected with Covid-19 must make a rather dangerous choice. The immune system must indeed fight the virus, but this war generates a significant inflammatory reaction which is not without risks.
This understanding of HSCs could therefore lead to a treatment for Covid-19 and other diseases. In the meantime, scientists are currently conducting a trial to determine if BCG vaccination can stimulate the HSC reaction without causing a significant inflammatory reaction.
