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Sunday, August 7, 2011

Don’t boost your immune system

‘Boosting’ your immune system may be the last thing you want to do if you have a cold, at least if you’re asthmatic.  According to a study led by Marc Hershenson from the University of Michigan Medical School, mice with a reduced immune response to cold viruses had less airway inflammation and bronchoconstriction during infection.

In the process of clearing our bodies of foreign invaders, our immune systems can sometimes cause more trouble than they’re worth.  For example, it is the immune response, not the infection, which is responsible for inflammation.  And it is certainly the immune response that causes allergic and autoimmune symptoms.  Apparently, it is also the immune system that exacerbates cold-induced asthma.

As Hershenson explains:
In our model, cold-induced asthma flare-ups were caused by the body's immune response to the virus, not the virus itself. Chemicals produced by the immune system inflame cells and tissues, causing asthma symptoms such as cough and wheeze.
Sure enough, mice that were immuno-deficient had less airway problems following infection with a cold virus than did mice with a normal immune response.  Of course, mice with no immune response could not fight off infections at all, so clearly a middle ground is best.