Scientists may have edged one step closer to a treatment that prevents life-threatening peanuts allergies.

Known as sublingual immunotherapy (SLIT), a minuscule amount of a liquefied peanut protein is placed underneath the tongue.

This gets rapidly absorbed into the bloodstream, where it works to densensitise the immune system to larger amounts of the protein. 

Scientists from the University of North Carolina tested the approach in 48 allergy sufferers, who received gradually increasing doses of the protein over five years.

At the end of the study, the patients could tolerate ‘between 10 and 20 times more peanut protein than it would take for someone to get sick’. 

Scientists may have edged closer to a treatment that prevents peanuts allergies (stock)

Scientists may have edged closer to a treatment that prevents peanuts allergies (stock)

‘As a parent of two children with nut allergies, I know the fear parents face and the need for better treatments,’ lead author Dr Edwin Kim said.

‘We now have the first long-term data showing that sublingual immunotherapy is safe and tolerable, while offering a strong amount of protection.’

Around 32 million Americans are thought to have food allergies, including 5.6 (one in 13) children, according to Food Allergy Research & Education.  

And in the UK, around 1.76 per cent of people are thought to be affected, Allergy UK statistics show. 

More than 170 foods have been reported to cause allergic reactions. Peanuts are in the top eight, alongside soy, wheat and shellfish. 

Just 100mg of peanut protein can trigger a severe reaction. A single peanut kernel contains around 300mg of this protein. 

Allergy sufferers could therefore be put at risk if they simply eat at a ‘facility that processes peanuts’, the researchers warn. 

Most allergic reactions cause symptoms like sneezing, itchy eyes and hives. In rare cases, they can trigger anaphylaxis. This can be deadly, with symptoms including swelling of the throat, difficulty breathing and loss of consciousness.  

SLIT was first tested in 2011 when 18 patients were given the preventative treatment for a year. Results suggested the approach was both safe and effective.

In the more recent study, 48 allergy sufferers were started on 2mg of the peanut protein, which gradually increased, every day for five years.

At the end of the study, 67 per cent of the patients could tolerate at least 750mg of the protein without suffering serious side effects. Around a quarter of them could tolerate 500mg. 

‘SLIT participants tolerated between 10 and 20 times more peanut protein than it would take for someone to get sick,’ Dr Kim said.

WHAT IS ANAPHYLACTIC SHOCK?

Anaphylaxis, also known as anaphylactic shock, can kill within minutes.

It is a severe and potentially life-threatening reaction to a trigger, such as an allergy.

The reaction can often be triggered by certain foods, including peanuts and shellfish.

However, some medicines, bee stings, and even latex used in condoms can also cause the life-threatening reaction.

According to the NHS, it occurs when the immune system overreacts to a trigger. 

Symptoms include: feeling lightheaded or faint; breathing difficulties – such as fast, shallow breathing; wheezing; a fast heartbeat; clammy skin; confusion and anxiety and collapsing or losing consciousness. 

It is considered a medical emergency and requires immediate treatment.

Insect stings are not dangerous for most victims but a person does not necessarily have to have a pre-existing condition to be in danger. 

An incremental build-up of stings can cause a person to develop an allergy, with a subsequent sting triggering the anaphylactic reaction.

In terms of safety, the most common adverse event was itchiness around the mouth, which lasted for around 15 minutes and did not require treatment. 

None of the study’s participants dropped out due to side effects. 

Immunotherapy is the go-to to prevent allergic reactions to substances like pollen, dust mites and insect venom.

It involves gradually exposing an allergy sufferer to increasing doses of the substance they are allergic to. 

As well as SLIT, a patch that releases small amounts of a peanut protein through a patient’s skin is being tested in trials.

This has been shown to be safe but may not be as effective as originally thought, the University of North Carolina scientists claim.

A second approach is oral immunotherapy (OIT), which is being reviewed by the US’ Food and Drug Administration (FDA). A decision is expected by the end of the year.

This requires a patient ingests a small amount of peanut protein. A late-stage trial had allergy sufferers consuming 0.5mg of the protein every day, which increased to 300mg over many weeks.

They continued to ingest 300mg a day for the rest of the year. This was ‘substantially effective’ at protecting patients but some suffered ‘serious side effects’.

A study review of OIT, published in The Lancet, later concluded more research into the approach is required due to the risk of adverse events. 

Dr Kim’s data suggests SLIT is as effective as OIT and safer, however, the former study was much smaller. 

‘We think this provides a good cushion of protection – maybe not quite as good as OIT – but with an easier mechanism (sublingually) and, as far as we can tell right now, a better safety signal,’ he said.

The same researchers have also finished a separate SLIT study, where 55 patients were given 4mg of the treatment every day for four years. Dr Kim hopes to publish the results by the end of the year.

‘With sublingual immunotherapy, we hope we can maintain our safety profile while seeing an even stronger benefit for patients,’ he said.

The team are also studying the approach in children aged one-to-four. This is after an OIT trial suggested young patients have a stronger and longer lasting response to immunotherapy. 

‘We focus on the idea there is no one perfect drug for food allergy,’ Dr Kim said.

‘There will have to be a lot of shared decisions between physicians, patients, and parents about what method of treatment is best for each patient. 

‘We think SLIT could be a good option for a subset of patients.’

 

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