3 days ago
‘Out of the box' pill could eliminate life-threatening allergic reactions for millions of people
POTENTIALLY deadly food allergies could be prevented by an asthma drug.
The breakthrough could lead to new protection for millions, say scientists.
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Zileuton, an oral pill used to treat asthma, worked "shockingly well" in blocking allergic reactions to food in mice in new research.
Researchers found the mice went from being 95 per cent susceptible to anaphylaxis to 95 per cent protected.
Now a clinical trial has been launched to test the same approach in humans.
Zileuton, recently approved in the United States and available on prescription in the UK, was found to "nearly eliminate" life-threatening allergic reactions to food allergens in mice.
The discovery came after scientists identified, in mice, a previously unknown role for a gene called DPEP1, which they found is "essential" in regulating anaphylaxis - a rapid and potentially deadly allergic reaction.
By using it to block the pathway involving this gene, the team at at Northwestern University in Illinois nearly eliminated allergic responses in mice that were previously highly susceptible to food-induced anaphylaxis.
The mice were given peanut extract orally shortly after receiving Zileuton while the team monitored for symptoms.
Study co-senior author Dr. Stephanie Eisenbarth, of Northwestern University Feinberg School of Medicine, said: "It was actually shocking how well Zileuton worked."
The discovery of the new pathway came after a years-long forward genetic screen, a process where researchers breed generations of mice to narrow down the specific genes responsible for biological differences, such as susceptibility to food allergy.
Once the team found the DPEP1 gene controlled leukotrienes in the gut - inflammatory molecules already targeted by asthma drugs - they tested Zileuton, which blocks their production.
Allergist explains the difference between allergies and anaphylaxis
Food allergies are on the rise, affecting around one in 10 people.
But scientists say predicting an allergic person's risk of anaphylaxis and preventing severe reactions from accidental exposure remains a challenge.
Currently, there are only two approved treatments for certain food allergies - and no cure.
One is an oral immunotherapy for peanut allergy, which doesn't work for all patients and can itself trigger anaphylaxis.
The other, omalizumab, is an expensive jab that also isn't effective for all allergy patients.
But the research team say Zileuton is a simple pill that temporarily shields allergy patients by blocking the body's anaphylactic pathway before it activates.
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Prof Williams said: "This is a totally different, out-of-the-box approach to treat food allergy, unlike anything we've tried before.
"We've seen tragic, even fatal reactions from hidden ingredients like ground peanuts in a sauce.
"For parents sending their child to a birthday party, or for anyone flying where they can't control what's being served, this could be a powerful protective drug."
The Northwestern team launched a small clinical trial in July to test whether blocking the newly identified pathway with Zileuton in humans is as effective as it was in mice.
Their findings, published in the journal Science, also shed light on the long-standing puzzle of why some people test positive for food allergens but experience no symptoms when they eat the food.
Dr Eisenbarth said: "Let's say you're told you're allergic to peanuts based on a blood test, but you've eaten peanuts your whole life without any problems.
"This pathway we discovered may be one explanation for why some of those people are protected."
She says that group has been a "challenge" for doctors and a source of stress for patients because current diagnostic tests only estimate allergy risk, not tolerance.
Dr Eisenbarth said: "Our findings open a whole new area for future research into how people develop food allergies in the first place, and why some react while others don't."
She added: "If you'd asked me five or six years ago to guess the pathway that would lead to this discovery, I never would have picked this gene or the leukotriene molecules."
Symptoms of anaphylaxis - and what to do if you have it
The symptoms of anaphylaxis can happen very quickly. They usually start within minutes of coming into contact with something you're allergic to, such as a food, medicine or insect bite.
You should call 999 if:
Your lips, mouth, throat or tongue suddenly become swollen
You're breathing very fast or struggling to breathe (you may become very wheezy or feel like you're choking or gasping for air)
Your throat feels tight or you're struggling to swallow
Your skin, tongue or lips turn blue, grey or pale (if you have black or brown skin, this may be easier to see on the palms of your hands or soles of your feet)
You suddenly become very confused, drowsy or dizzy
Someone faints and cannot be woken up
A child is limp, floppy or not responding like they normally do (their head may fall to the side, backwards or forwards, or they may find it difficult to lift their head or focus on your face)
What to do if you have anaphylaxis
Follow these steps if you think you or someone you're with is having an anaphylactic reaction...
Use an adrenaline auto-injector (such as an EpiPen) if you have one – instructions are included on the side of the injector.
Call 999 for an ambulance and say that you think you're having an anaphylactic reaction.
Lie down – you can raise your legs, and if you're struggling to breathe, raise your shoulders or sit up slowly (if you're pregnant, lie on your left side).
If you have been stung by an insect, try to remove the sting if it's still in the skin.
If your symptoms have not improved after 5 minutes, use a 2nd adrenaline auto-injector.
Do not stand or walk at any time, even if you feel better.
