Immunotherapy – do NOT try this at home….

Immunotherapy, especially when combined with probiotics (see Kate Lawrence’s research reports this week), shows great promise as a treatment for life threatening allergies. But while the outcome for those who have been treated has been very positive, it is still fraught with danger.

Essentially immunotherapy seeks to ‘teach’ the immune system that the peanut, milk, pollen, or whatever it sees as threatening and to be expelled as quickly and violently as possible, is actually perfectly safe. (For a detailed description of exactly what immunotherapy is and does see Linda Gamlin’s article on the FoodsMatter site here.)

In immunotherapy the allergic person is fed such tiny amounts of the allergic protein (initially 5mg of, say, peanut protein) that the immune system does not recognise it as dangerous. Then that dose is very gradually increased to the point that the immune system will accept relatively large amounts of the allergen (several whole peanuts for example) without reacting. The treatment has been in use the in US for some years but was given a significant boost in the UK by the successful outcome of the 2014  trial at Addenbrookes led by Drs Andrew Clarke and Pamela Ewan. This showed that after 6 months over 80% of the 99 peanut anaphylactic children in the trial could eat the equivalent of 5 peanuts a day without having any reaction.

The result got a good deal of publicity at the time, and since – which was excellent in terms of raising awareness of peanut allergy. But the publicity had a down side in that people grasped the essential principle (that you could ‘educate’ the immune system to to react to allergens) but did not grasp the dangers inherent in the treatment – as in this case I heard of yesterday.

The parents of a ten year old believed that he had a peanut allergy as he had reacted badly to peanuts when he was younger, but he had never been tested or officially diagnosed. He just avoided peanuts.  Having read about how you could ‘cure’ a peanut allergy by feeding the sufferer very small but increasing amounts of peanuts the parents decided to try to ‘cure’ him themselves by feeding him tiny doses, starting with a lick of peanut butter. But after just one lick he felt sick and his tongue started to itch, so they stopped and did not resume the experiment. They were lucky. That one lick could have been fatal.

So why was that such a dangerous thing to do?

• You do not know at any point how serious an allergy is or has become. A first relatively mild reaction can escalate into a full blown anaphylactic episode on the second exposure for no apparent reason. You will get no warning and it could happen at any time.
• This is why, if you suspect a serious allergy, be it to peanuts, milk, egg or any other food, you should get tested as soon as possible and you should always carry an adrenaline auto-injector (ideally two) to use should you have an anaphylactic reaction.
• Although over 80% of the children in the Addenbrookes trial were fine on the incremental doses of peanut, the other 20% were not – and until you start the trial you will not know which group you or your child will fall into. Although none of that 20% of children did go into anaphylactic shock, any of them could have done. So it is essential that the initial doses at least are administered in a controlled environment with expert medical assistance at hand in case you or your child do react. They should not be administered in your kitchen at home.

Moral of the story: immunotherapy  is an excellent thing – but do NOT try it at home.

For more see the Cambridge Peanut Allergy Clinic website.