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Flu's Misery May Lie in the Genes: Certain DNA could spur worse symptoms

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  • Flu's Misery May Lie in the Genes: Certain DNA could spur worse symptoms

    http://www.cbc.ca/cp/HealthScout/061103/6110312U.html


    21:29:35 EST Nov 3, 2006

    Canadian Press: AMANDA GARDNER /HEALTHDAY REPORTER

    <!--end of storyhead--><!--updated p--><!--updated para--><!-- CPPara1-->(HealthDay News) - If the flu hits you especially hard this season, blame it on your DNA.

    <!-- CPPara1End--><!--updated p--><!--updated para--><!-- CPPara2-->A new study of flu-infected mice found that certain genes spurred a strong immune response in the lungs that led to much more severe illness. Mice that didn't exhibit such an immune response were more likely to recover, the researchers found.

    <!-- CPPara2End--><!--updated p--><!--updated para--><!-- CPPara3-->The findings may help humans not only survive the annual flu season but also an avian flu pandemic, should it ever arise.

    <!-- CPPara3End--><!--start of p-->"The long-term implications would fit into the idea of genetically based preventive medicine," explained co-researcher Dr. Linda Toth, associate dean of research at Southern Illinois University School of Medicine in Springfield. "To know that some people are predisposed to any kind of disease, we would be able to better advise or monitor those people so as to limit their health risk."

    <!--start of p-->This knowledge might also help public health officials allocate precious resources.

    <!--start of p-->"In the case of influenza, viral treatments and vaccine are in limited availability and if we had this kind of information, it could potentially be used to target the resources to those most at risk," Toth said.

    <!--start of p-->She and co-researcher Rita Trammell, an assistant professor of internal medicine at Southern Illinois University School of Medicine, were expected to present the findings Friday at a meeting of the American Physiological Society, in Fort Lauderdale, Fla.

    <!--updated p-->
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    Another expert said the research has implications for the treatment of flu.
    <!--start of p-->"It brings up the question of whether anti-inflammatories have a role in treating a flu with a lot of inflammation," said Dr. Marc Siegel, author of Bird Flu: Everything You Need to Know About the Next Pandemic and clinical associate professor of medicine at New York University School of Medicine in New York City. "It also brings up the question of 'Does genetics allow you to anticipate which group is going to have a more deleterious inflammatory response?' That would be very helpful epidemiologically."

    <!--start of p-->The question of who dies of influenza has been a hot topic since at least the 1918 pandemic, which killed millions of people around the world. At the time, doctors noted that the immune systems of young, robust adults often "overreacted," resulting in a severe and often deadly inflammation of the lungs.

    <!--start of p-->"This has been a long-time concern of scientists since 1918, when the theory was that people drowned in their own secretions," Siegel explained. "The body sees influenza and responds with a strong immunological response, and that response can lead to a lot of secretions."

    <!--start of p-->The 1918 pandemic and the current avian flu - which has so far killed only a small number of humans - have some similarities: Both cause an intense inflammatory and immune response in the lungs of mice and people.

    <!--start of p-->"With the current avian influenza as well as the influenza from the 1918 pandemic, the influenza caused a really enhanced and intense inflammatory and immune response in the lungs which killed the mice," Trammell said. "This was really important in determining why they died. We wanted to look at the background genetics of mice, how they reacted differently."

    <!--start of p-->In their research, Trammell and Toth infected two strains of laboratory mice - called Types "B" and "C" - with an influenza A virus. Past work had shown that about half of the Type B mice would die, compared to about 10 percent of the Type C mice.

    <!--start of p-->When lung tissue from the mice was examined about 30 hours after infection, the authors found that levels of all the pro-inflammatory cytokines (with one exception) were elevated and were much higher in the sensitive mice. This indicates a more severe inflammatory response, the researchers said. Cytokines are proteins that can cause inflammation when an immune response is mounted.

    <!--start of p-->Despite the variation in inflammation, the level of the virus in the rodents' lungs was about the same in both groups.

    <!--start of p-->A second, related study found that levels of immune-related messenger RNA (mRNA) in Type B mice were on average 24 times higher (and sometimes 100 times higher) than in uninfected mice. The mRNA levels in Type C mice increased less than three-fold after infection.

    <!--start of p-->The next step?

    <!--start of p-->"We want to try to identify specific genes or the array of genes that contribute to either the resistance or the severe response to the virus," Toth said. "Right now, we have some ideas, but we haven't nailed that down definitively."

    <!--start of p-->Trammell said that this type of information, "would have enormous implications for understanding and avoiding the fatality associated with influenza virus."

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    <!--start of p-->Copyright 2006 ScoutNews, LLC. All rights reserved

    .
    "The next major advancement in the health of American people will be determined by what the individual is willing to do for himself"-- John Knowles, Former President of the Rockefeller Foundation

  • #2
    Re: Flu's Misery May Lie in the Genes: Certain DNA could spur worse symptoms

    Originally posted by AlaskaDenise
    ......Despite the variation in inflammation, the level of the virus in the rodents' lungs was about the same in both groups......
    Is saying that our speculation about the implications of viral load may not always be true?

    .
    "The next major advancement in the health of American people will be determined by what the individual is willing to do for himself"-- John Knowles, Former President of the Rockefeller Foundation

    Comment


    • #3
      Re: Flu's Misery May Lie in the Genes: Certain DNA could spur worse symptoms

      I thought the speculation was intital viral load, or loading dose- that the higher the load in the beginning, the more chance of an "exhuberant immune response". I'd venture a guess that for study purposes, the loading dose on each group of mice was identicial.

      I have a feeling the issue is going to end up to be multifactorial- we'll learn that there are more than one factors that influence this. The age related affect on cytokine storm victims is a clue. The working theory is that the younger immune systems respond more vigorously -but I'm not sure that will end up being the answer.

      If it was just genetics, I think we'd have seen more variation in population groups in 1918. I dont recall mantion of certain sub groups being more seriosuly affected- at least among those of European background.

      There were higher rates of death and illness in some groups-such as Eskimo and other Native American villages that were nearly wiped out. IIRC there were suggestions of cause on this, other than genetic susceptability-complete naivety IIRC, similar to the reason smallpox, measles and other European imports were so devastating.

      I wonder if we will learn these things this time around. I have a hard time trying to keep straight what is proven fact and what is hypothesis.
      Upon this gifted age, in its dark hour,
      Rains from the sky a meteoric shower
      Of facts....They lie unquestioned, uncombined.
      Wisdom enough to leech us of our ill
      Is daily spun, but there exists no loom
      To weave it into fabric..
      Edna St. Vincent Millay "Huntsman, What Quarry"
      All my posts to this forum are for fair use and educational purposes only.

      Comment


      • #4
        Re: Flu's Misery May Lie in the Genes: Certain DNA could spur worse symptoms

        For those who don't know Marc Siegel, do a search here and in the press.
        Dr. Siegel certainly deserves to be recognized for his prior opinions. They will guide you in your assessment of what he has been quoted as saying hereinabove.

        Comment


        • #5
          Re: Flu's Misery May Lie in the Genes: Certain DNA could spur worse symptoms

          In case GR's analysis was too subtle, let me rephrase it. Siegel is a joke.

          Comment


          • #6
            Re: Flu's Misery May Lie in the Genes: Certain DNA could spur worse symptoms

            Do certain genetic/racial/regional groups have a greater affinity for SEASONAL flu?

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