Influenza Genetic Susceptibility Gene?

Thursday, March 29, 2012 // Uncategorized

Why do some people seem to get sicker from the flu?  Some strains seem to be more virulent and this has been the focus of research in the past, but ProMED digest reports on research published in Nature that indicates that there may be differences inthe way some people respond.



A ProMED-mail post
ProMED-mail is a program of the
International Society for Infectious Diseases

Date: Sun 25 Mar 2012
Source: BBC News Health [edited]
Gene flaw linked to serious flu risk
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Scientists have identified a genetic flaw that may explain why some
people get more ill with flu than others. Writing in Nature, the
researchers said the variant of the IFITM3 [interferon-inducible
transmembrane (IFITM) protein] gene was much more common in people
hospitalised for flu than in the general population. It controls a
malformed protein, which makes cells more susceptible to viral
infection. Experts said those with the flaw could be given the flu
jab, like other at-risk groups.

Researchers removed the gene from mice. They found that when they
developed flu, their symptoms were much worse than those seen in mice
with the gene. Evidence from genetic databases covering thousands of
people showed the flawed version of the gene is present in around one
in 400 people.

The scientists, who came from the UK and US, then sequenced the IFITM3
genes of 53 patients who were in hospital with flu. 3 were found to
have the variant — a rate of one in 20. The researchers say these
findings now need to be replicated in bigger studies. And they add it
is probably only part of the genetic jigsaw that determines a person’s
response to flu.

Professor Paul Kellam of the Wellcome Trust Sanger Institute, who
co-led the research, said: “At the moment, if someone is in a more
vulnerable group because of co-morbidity [another health problem],
they would be offered the flu vaccine. But he said having this variant
would not make any difference to how people were treated. Prof Kellam
added: “Our research is important for people who have this variant as
we predict their immune defences could be weakened to some virus
infections. Ultimately as we learn more about the genetics of
susceptibility to viruses, then people can take informed precautions,
such as vaccination to prevent infection.”

Professor Peter Openshaw, director of the Centre for Respiratory
Infection at Imperial College London, said: “This new discovery is the
1st clue from our detailed study of the devastating effects of flu
hospitalised patients. It vindicates our conviction that there is
something unusual about these patients.” Sir Mark Walport, director of
the Wellcome Trust, said: “During the recent swine flu pandemic, many
people found it remarkable that the same virus could provoke only mild
symptoms in most people, while, more rarely, threatening the lives of

“This discovery points to a piece of the explanation: genetic
variations affect the way in which different people respond to
infection. This important research adds to a growing scientific
understanding that genetic factors affect the course of disease in
more than one way. Genetic variations in a virus can increase its
virulence, but genetic variations in that virus’s host — us — matter
greatly as well.”

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Communicated by:
ProMED-mail Rapporteur Mary Marshall

[The following is the Nature press re-release relating to this paper

Everitt AR, Clare S, Pertel T, et al: IFITM3 restricts the morbidity
and mortality associated with influenza. Nature. 2012 Mar 25. doi:
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