To analyze whether the sensitization profile towards hazelnut, peanut and birch pollen and their major individual allergens can be used to predict whether the hazelnut allergy is associated without/with mild clinical symptoms or severe clinical…
ID
Source
Brief title
Condition
- Allergic conditions
Synonym
Research involving
Sponsors and support
Intervention
Outcome measures
Primary outcome
Based on literature and preliminary data, four determinants are identified,
which we think are (most) predictive for the severity of the symptoms of
hazelnut allergy. The determinants are: Cor a 1, Cor a 8, Cor a 9 and oleosin.
First, the predictive value of each determinant will be assessed using
univariate analysis. Second, a multivariable logistic regression model will be
build starting with the strongest predictor (based on the relative risk
obtained from univariate analysis).
To make the prediction model applicable for clinical practice, a prediction
rule will be made and for the different possible scores on the prediction rule
(or categories of the score), we will present the probability of having severe
symptoms of hazelnut allergy.
Secondary outcome
The analysis of IgE and T cell cross-reactivity concerns a secondary analysis
to define potential mechanisms responsible for the difference in clinical
severity of symptoms. We determine whether there are genetic associations by
analysing these polymorfisms.
Background summary
Together with other tree nuts and peanut, hazelnut accounts for 90% of
fatalities due to food allergy. Hazelnut allergy is present in both children
and adults. Children with hazelnut allergy, have more frequently severe
symptoms compared to adults with hazelnut allergy. There are indications that
differences in the clinical spectrum are related to differences in allergen
recognition. Mild symptoms for hazelnut have been associated with hazelnut
allergens that are cross-reactive with birch pollen. Severe symptoms for
hazelnut are possibly related to hazelnut allergens that are cross-reactive
with peanut and other tree nuts. These co-sensitizations could be the result of
IgE cross-reactivity between homologous allergens in hazelnut, peanut and birch
pollen. There are indications that this sensitization profile is different in
children compared to adults. Preliminary data suggest that in children
sensitization for the hazelnut allergen Cor a 8, which is homologous to Ara h 9
in peanut, is correlated to severe hazelnut allergy. In contrast, adults with
severe hazelnut allergy have hardly any Cor a 8 sensitization. It would be
helpful if the sensitization pattern could be used to predict (the severity of)
the hazelnut allergy. The preliminary data suggest that this predictive pattern
may differ between children and adults. The mechanism underlying the diversity
of the clinical symptoms is badly understood.
Recent discovered polymorfisms in genes, which are important for skin and lung
barrier function and regulation of immune responses, predispose for atopy.
These polymorfisms could play a role in the route of sensitization and the
prediction of the severity of the hazelnut allergy.
Study objective
To analyze whether the sensitization profile towards hazelnut, peanut and birch
pollen and their major individual allergens can be used to predict whether the
hazelnut allergy is associated without/with mild clinical symptoms or severe
clinical symptoms. Additionally, analysis of potential cross-reactivity between
hazelnut, peanut and/or birch pollen, may provide inside into the primary
sensitizing allergen and the route of sensitization. This may help to
understand the mechanism leading to the observed diversity in the severity of
hazelnut allergy.
Study design
Serum and peripheral blood mononuclear cells (PBMCs) will be collected from
children and adults with a hazelnut sensitization without/with mild or severe
clinical symptoms. The sensitization profile towards hazelnut, peanut and birch
pollen (both total extract and major allergens) will be analysed by CAP,
immunoblot, allergen chip and basophil activation test. The role of
cross-reactivity and the primary sensitizing allergen will be analysed by
immublot and CAP-inhibition assays. Whether cross-reactivity at the T cell
level underlies cross-reactivity at the IgE level will be investigated by
analysis of the allergen-specific response in hazelnut-, peanut- and birch
pollen-specific T cell lines towards cross-reactive allergens. We will use a
protein-truncation test, PCR and sequencing to determine the polymorfisms.
Study burden and risks
Blood will be collected from children and adults participating in this study
(10 ml 3-6 years, 30 ml 7-11 years, 40 ml 12-15 years and 60 ml >16 years).
Children with a high risk upon an allergic reaction during DBPCFC will get a
drip, this is a standard procedure. High risk is defined as an anaphylactic
shock or dyspnoea after hazelnut ingestion according to the history or a
hazelnut CAP > 15 or SPT from 2+ or more. In these children the blood will be
collected from the drip. Children from 3-6 years will not be exposed to a
venepuncture. Children from 7 years, without a blood collection during the
DBPCFC and adults will get a venepuncture for blood collection. This can cause
some pain and can result in a small haematoma.
Heidelberglaan 100
3584 CX Utrecht
NL
Heidelberglaan 100
3584 CX Utrecht
NL
Listed location countries
Age
Inclusion criteria
children and adults with a hazelnut sensitization
Exclusion criteria
congenital/aqcuired immunodeficiency
lymphoproliferative disease
systemic immunosuppression
insufficient knowledge of Dutch language
children from 3-6 years will be excluded from genetic research
Design
Recruitment
Followed up by the following (possibly more current) registration
No registrations found.
Other (possibly less up-to-date) registrations in this register
No registrations found.
In other registers
| Register | ID |
|---|---|
| CCMO | NL27799.041.09 |