I know that celiacs and some others can't tolerate even cross-contamination of gluten, casein, nuts, etc.
Perhaps someday this desensitization technique (similar to allergy shots for pollen) may prove useful in all food allergens like gluten, soy, dairy, seafood, etc.
NOTE: I'm not promoting eating these allergens in bulk - they have many other issues. But it makes life easier for those with severe allergies so they can eat at social events and travel with less stress and not have to deal with cross-contamination. Do you know of other allergens that this has been successfully used in?
http://www.bbc.co.uk/news/health-18888172 Makes a reference to peanut desensitization
BACKGROUND For egg allergy, dietary avoidance is the only currently approved treatment. We evaluated oral immunotherapy using egg-white powder for the treatment of children with egg allergy.
METHODS In this double-blind, randomized, placebo-controlled study, 55 children, 5 to 11 years of age, with egg allergy received oral immunotherapy (40 children) or placebo (15). Initial dose-escalation, build-up, and maintenance phases were followed by an oral food challenge with egg-white powder at 10 months and at 22 months. Children who successfully passed the challenge at 22 months discontinued oral immunotherapy and avoided all egg consumption for 4 to 6 weeks. At 24 months, these children underwent an oral food challenge with egg-white powder and a cooked egg to test for sustained unresponsiveness. Children who passed this challenge at 24 months were placed on a diet with ad libitum egg consumption and were evaluated for continuation of sustained unresponsiveness at 30 months and 36 months.
RESULTS After 10 months of therapy, none of the children who received placebo and 55% of those who received oral immunotherapy passed the oral food challenge and were considered to be desensitized; after 22 months, 75% of children in the oral-immunotherapy group were desensitized. In the oral-immunotherapy group, 28% (11 of 40 children) passed the oral food challenge at 24 months and were considered to have sustained unresponsiveness. At 30 months and 36 months, all children who had passed the oral food challenge at 24 months were consuming egg. Of the immune markers measured, small wheal diameters on skin-prick testing and increases in egg-specific IgG4 antibody levels were associated with passing the oral food challenge at 24 months.
CONCLUSIONS These results show that oral immunotherapy can desensitize a high proportion of children with egg allergy and induce sustained unresponsiveness in a clinically significant subset. (Funded by the National Institutes of Health; ClinicalTrials.gov number, NCT00461097.)
asked byLady_Arwen (6259)
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on July 21, 2012
at 11:07 AM
It is interesting and it is good to see more research on this topic but there are a couple of points worth making.
Firstly this desensitization technique applies to IgE food allergies such as egg allergy which people, children in particular, can often grow out on their own. Coeliac disease is not the same as a food allergy and this technique would not work with gluten exposure for people with coeliac disease and would only make them ill.
Secondly, the doses used to start with were very very tiny and the degree of response in the children was assessed before the study started.
They started out in a research setting giving the children a dose of 0.1 milligrams of raw egg protein powder and then doubling the dose every 30 minutes up to a maximum of 50 milligrams. So the children were assessed throughout this time by professionals for the level at which they started to react.
(To imagine how small an amount this starting dose is 0.1 mg of egg protein is roughly 80,000 times smaller than the amount of protein in a egg while 50 milligrams is 160 times less).
When the maximum dose of up to 50 mg for each child was worked out the children were provided with one dose of egg protein powder per at this level. The dose was increased by 25% every two weeks for 10 months to a maximum of 2 grams a day. After this the children carried on taking this dose for the next 22 months before being tested for allergic responses. 2 grams is about the same as a quarter of an egg.
The main point of this is that they started out with very small exposures in a regular controlled manner. You could not expect the same effect from food as exposure would vary a lot and could trigger worsening of the allergy.
on July 21, 2012
at 04:21 AM
It depends on the allergen.
Some allergies, such as those to cat dander will improve as the immune system becomes less sensitive to the allergen.
With others like poison ivy, more exposure simply primes the immune system to go into overdrive, having the opposite effect.
on July 21, 2012
at 07:59 AM
I think this is a hugely interesting and important topic. I'll start my answer by saying I'm hesitant to use to the term "desensitzation" in this context.
In the egg study you showed, it's not immediately clear how intolerance was cured, but the IgG4 antibodies give us a clue. In the context of food sensitivity, immunoglobulins often grab antigenic proteins and render them inert. This says to me that those who passed the food challenge were still reactive to whatever egg antigen was causing them trouble in the first place, but now their body was secreting IgG to neutralize that antigen just like it would against pathogenic bacteria.
In most cases increased immunoglobulins (like in the egg study) and increased enzymes capable of metabolizing the antigen can stop a food intolerance. But this in my mind is the equivalent of armor, not desensitization.
I liked Jamie's comment on this question a lot. He said "I think a good question is why are peoples immune systems generally so sensitive in the first place". I think this is a great question and the answer will likely give us ideas on how to end many food intolerances. Yes, I think in some cases introducing small amounts of the problematic food may be useful, but again this will just be armor. Ultimately I think this method should take a back seat to figuring out how to eliminate the actual problematic response to the food when such armor is off.
on July 21, 2012
at 01:42 PM
NO, unless they're pet allergies.