Bacteria from a family that includes potentially deadly infectious bugs may protect against food allergies, research has shown.
Clostridia encompasses around 100 bacterial species, some of which live harmlessly in the gut.
Others are responsible for gangrene, tetanus, botulism food poisoning and hospital infections caused by Clostridium difficile.
Gut bacteria hold the key to beating food allergies, researchers say
The
new study suggests that 'friendly' Clostridia have a unique ability to
block the harmful immune response behind food allergies.
new study suggests that 'friendly' Clostridia have a unique ability to
block the harmful immune response behind food allergies.
Tests
on 'sterile' mice sensitised to peanuts showed that introducing a
Clostridia cocktail into their bacteria-free guts reversed their
allergy.
on 'sterile' mice sensitised to peanuts showed that introducing a
Clostridia cocktail into their bacteria-free guts reversed their
allergy.
Re-introduction of another major group of gut bacteria, Bacteroides, did not have the same effect.
Tests
indicated that Clostridia caused immune cells to produce high levels of
a signalling molecule known to decrease permeability of the intestinal
lining.
indicated that Clostridia caused immune cells to produce high levels of
a signalling molecule known to decrease permeability of the intestinal
lining.
This in turn reduced the chances of allergens - molecules that trigger an allergic reaction - leaking into the bloodstream.
US
lead scientist Professor Cathryn Nagler, from the University of
Chicago, said: 'We've identified a bacterial population that protects
against food allergen sensitisation.
lead scientist Professor Cathryn Nagler, from the University of
Chicago, said: 'We've identified a bacterial population that protects
against food allergen sensitisation.
'The
first step in getting sensitised to a food allergen is for it to get
into your blood and be presented to your immune system. T
first step in getting sensitised to a food allergen is for it to get
into your blood and be presented to your immune system. T
'he presence of these bacteria regulates that process.'
Environmental
effects on gut flora - including over-use of antibiotics, high fat
diets, excessive hygiene and even infant formula feeding - may be
contributing to food allergies by suppressing Clostridia, the
researchers believe.
effects on gut flora - including over-use of antibiotics, high fat
diets, excessive hygiene and even infant formula feeding - may be
contributing to food allergies by suppressing Clostridia, the
researchers believe.
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Their findings appear in the journal Proceedings of the National Academy of Sciences.
Mice
used in the study were either raised from birth in sterile conditions
or treated with antibiotics as newborns to wipe out most of their gut
bacteria.
used in the study were either raised from birth in sterile conditions
or treated with antibiotics as newborns to wipe out most of their gut
bacteria.
Both
groups were sensitised by exposing them to peanut allergens, triggering
a strong immune response. They produced significantly higher levels of
peanut-targeting antibodies than mice with normal populations of gut
bacteria.
groups were sensitised by exposing them to peanut allergens, triggering
a strong immune response. They produced significantly higher levels of
peanut-targeting antibodies than mice with normal populations of gut
bacteria.
When
Clostridia was present, immune cells generated high levels of the
protective signalling molecule, interleukin 22 (IL-22). But when IL-22
was neutralised, levels of allergen in the animals' bloodstreams
significantly increased.
Clostridia was present, immune cells generated high levels of the
protective signalling molecule, interleukin 22 (IL-22). But when IL-22
was neutralised, levels of allergen in the animals' bloodstreams
significantly increased.
The team has already been able to reverse peanut allergies in mice
The team is now working on turning the discovery into a probiotic food allergy treatment, and has filed a provisional patent.
'It's
exciting because we know what the bacteria are; we have a way to
intervene,' said Prof Nagler. 'There are of course no guarantees, but
this is absolutely testable as a therapeutic against a disease for which
there's nothing.
exciting because we know what the bacteria are; we have a way to
intervene,' said Prof Nagler. 'There are of course no guarantees, but
this is absolutely testable as a therapeutic against a disease for which
there's nothing.
'As a mom, I can imagine how frightening it must be to worry every time your child takes a bite of food.'
Between 6% and 8% of children in the UK are believed to have a diagnosed food allergy.
Since 1990, the number of annual UK hospital admissions due to food allergy reactions has soared by 500%.
Severe
food allergy can cause anaphylaxis, an extreme immune reaction that may
prove fatal. Common triggers for anaphylaxis include peanuts, tree nuts
such as almonds, walnuts and cashews, sesame, fish, shellfish, dairy
products and eggs.
food allergy can cause anaphylaxis, an extreme immune reaction that may
prove fatal. Common triggers for anaphylaxis include peanuts, tree nuts
such as almonds, walnuts and cashews, sesame, fish, shellfish, dairy
products and eggs.
