# 985
The sobering mortality rate from the H5N1 virus has been blamed, in large part, on a physiological process known as the Cytokine Storm. This is a poorly understood immune response launched by the body when combating an overwhelming infection.
It seemed an elegant explanation.
The H5N1 virus, much like the 1918 Spanish Flu, thus far has exacted a heavy toll on the youngest and healthiest victims. That fit with the idea that a robust immune system was over reacting and killing it's host.
Elegant or not, a study released today by St. Judes Medical Research Hospital seems to refute that idea.
Dr. Robert Webster and his group, using mice with genetically impaired immune systems, discovered that they succumbed to the virus at the same rate as healthy mice.
This study suggests that while a Cytokine Storm might play into some cases, the H5N1 virus replicates so much faster than regular influenza viruses that it, not the immune response, is largely responsible for patient's deaths.
This would seem to dash hopes of using immuno-suppressant drugs to combat avian flu, basically leaving us with anti-virals as our primary defense.
This from the Canadian Press, penned by Helen Branswell.
Dialling down immune response to bird flu won't protect against death: study
TORONTO (CP) - New research suggests successful treatment of the H5N1 avian flu virus requires targeting the virus, not the overwhelming immune response it triggers.
The study, done in mice genetically engineered to lack critical immune system chemicals called cytokines, found these mice were as likely to die from H5N1 infection as mice armed with an intact immune system.
That suggests the activity of the virus, not the immune response it induces, is the main driver of the disease process, said the authors, from St. Jude Children's Research Hospital in Memphis, Tenn.
As such, it is evidence that a phenomenon known as a "cytokine storm" - a massive and cascading production of immune system chemicals that actually damages the host it is meant to protect - is not responsible for the astonishing death rates seen in H5N1 infections.
"These results refute the popular paradigm that the cytokine storm is the cause of death during H5N1 infection," said the researchers, led by influenza guru Dr. Robert Webster.
