Determination of Minimum and Non-provoking Doses of Soy Protein in Soy Allergic Individuals

Soy-allergic individuals and their clinicians would benefit from knowing their
individual minimum eliciting dose for soy protein. This information is
beneficial in that it assists the clinician and the individual in assessing
clinical reaction risk and in implementing suitable avoidance diets.

Soy-allergic individuals will also benefit because the food processing industry
and government agencies that regulate it will improve their practices as a
result of knowledge gained regarding the minimal eliciting dose for soy
protein.

Determining the thresholdlevel for a group of soy-allergic individuals will
also be beneficial in the development and refinement of immunoassay tests used
to detect soy residues in foods.

Additionally, ingredients derived from soy are ubiquitous in the food industry
and include soy flour (used in this study), soy oil, lecithin, soy protein
concentrates and isolates, and soy sauce. Some of these soy-derived
ingredients contain high percentages of soy protein (soy flour, soy protein
concentrates and isolates) while others contain very low amounts of soy protein
(soy lecithin and soy oil). Currently, soy-allergic consumers are advised to
avoid all soy-derived ingredients. But, with knowledge of the thresholdlevel
for soy protein, it may be possible to advise soy-allergic individuals that
certain soy-derived ingredients are safe to consume.

The serum will be used for testing specific immunoglobulin E (IgE) for soy.
This can be used in further research.

The purposes of this study are to determine a threshold level for soy protein
when consumed by soy-allergic individuals.

World wide 29 soy allergic individuals wil be included.
5-10 Dutch patients will be included via the allergy outpatient clinic from the
University Medical Center Utrecht

Visit1:
If the resulsts of the blood- and skin prick test (SPT) are older than 6
months, they will be performd again.
A special questionnaire will be filled in.

If the results of the SPT and IgE-soy are positive the patients are invited to
the challenges

Visit 2+3:
A double blind challenge will be pergormed over 2 days.
One day the portions will contain soy flour, and one day the porions will be
placebo.
Randomisation will take place by the shake of a die.
The blinded portions will be prepared by FARRP
Patients will be challenged with five 20 grams portions of soy four in a
granola cereal or with placebo portions.
The doses will be given with a 30 min. interval
Doses are : 0.1 mg, 1,0 mg 10 mg, 100 mg, 1000 mg soy protein.
The doses will be repeated once if there is a question about the objectivety
of the reaction.
If there is no reaction on both days, a open challenge will be performed at the
end of day 2.
the open challenge consits of 8 ounces of commercially availeble soy milk
On both challenge days the patients will get a periferal drip, though which
also the bloodwithdrawel can take palce of the 50-80 ml blood.
Afterwards the patients have a cunsultation with the doctor and if necessary
with the dietician.

Patients have to temporary stop antihistamines 3-7 days before the SPT and the
challenges.
Patients may not use caffeine and alcohol 24 hours before the challenges.

The intervention that may take place during the screening:
A skin prick test.
Only if the results of the IgE for soy are older than 6 months, this will be
determined again.

After inclusion a double blind placebo contolled food challenge will be
performed:
- Patients will get an intravenous line, to administer medication if necessary.
-The patientes have to eat portions muesli, which may contain, increasing doses
of soy proteine.
If an objective allergic reaction has taken place, the challenge will stop,
and medication will be administerd, to decrease the reaction.

Visit 1:
The burden in visit 1 is low.
Visit 2+3:
To confirm the diagnosis and to determine the threshold level according to
international guidelines, it is necessary that objective symptoms occur during
the challenge, or persistent subjective symptoms. Mostly these symptoms are
relatively mild to moderately severe. (Itch in mouth, urticaria, nausea,
stomach ache). These symptoms are similar to the symptoms that the patients
experience when they ate something wrong.
Sometimes the symptoms have a more severe character. (tightness of the throat,
vomiting, angioedema). Patients react -almost always- directly when medication
is administered (corticosteroids, antihistamines, and sometimes epinephrine).
Sometimes it takes several hours for the symptoms to disappear completely. If
needed, patients can stay a night at the dermatology ward. In the regularly
patient care this is included also.
Determining the threshold level is important for multiple reasons. For the
present and future diet of the patient, for the food industry, for the
governments and for further research in diagnostics and treatment of food
allergy.


(We want to indicate that we agreed with the sponsor to challenge between 5
and 10 patients. In this form you can only indicate one number, and not two
numbers.)