Google swine flu and cytokine storm and you’ll find lots of articles.
I found a brief synopsis in the wikipedia article:
It is believed that cytokine storms were responsible for many of the deaths during the 1918 influenza pandemic, which killed a disproportionate number of young adults.[1] In this case, a healthy immune system may have been a liability rather than an asset. Preliminary research results from Hong Kong also indicated this as the probable reason for many deaths during the SARS epidemic in 2003.[6] Human deaths from the bird flu H5N1 usually involve cytokine storms as well.[7] Recent reports of high mortality among healthy young adults in the 2009 swine flu outbreak has led to speculation that cytokine storms could be responsible for these deaths.[8]
http://en.wikipedia.org/wiki/Cytokine_storm