Spanish flu: Dangerous overreaction of the immune system
The so-called Spanish flu, which claimed the lives of up to fifty million people in 1918, was so deadly, according to American scientists, partly because it triggered an overreaction in the immune system.
John Kash and his colleagues from the University of Washington in Seattle had infected laboratory mice with the reconstructed virus from back then. They then examined the lung tissue of the sick animals and compared it with the tissue of mice that had contracted the normal flu.
Analysis of gene activity in the lungs revealed that the immune response to an infection with the Spanish flu was much stronger: an overproduction of inflammatory factors drove too many cells to death. Normally, this programmed cell death only eliminates cells that are already badly affected.
According to the new findings, not only should the pathogen be fought in comparable viral infections, but the immune response should also be regulated. However, it should not be strengthened as is usual with flu, but should be weakened. This could also apply to bird flu, which also uses similar mechanisms.