Selective Gamba Food Allergy

Allergy to seafood is a common problem. The main allergen of shrimp and related
shellfish is tropomyosin. Tropomyosin is responsible for cross-reactivity
between dust mites and seafood.(Arthropodas) Because of this cross-reactivity
patients with an allergy to shrimp are advised to avoid all shellfish.
Sporadically, patients are seen with an allergy to gamba withouta clear-cut
allergy to dust mite. Cross-reacting allergens seem to play no role here. In
recent years, although several other shellfish allergens have been identified,
it is not yet clear which of all play a role in allergy to gamba's. Since the
etiology of gamba's is still not entirely clear, it is impossible to predict
reactions of these patients to other crustaceans. Till now the general advice
in these patients is avoidance of all crustaceans which might not be necessary.

The aim of the study is to identify patients with selective gamba-allergy and
sensitization patterns for the various allergens in gamba extracts.
Comparing sensitization patterns between patients who clinically react to Gamba
with patients having a house dust mite allergy combined with a shrimp allergy,
will hopefully give us more understanding of the clinical relevance of
cross-sensitization between gamba and shrimp and the molecular basis of it.
Furthermore, we want to investigate whether the specific allergic reaction to
gamba is caused by the presence of IgE-antibodies against proteins in the
gamba, without IgE against possible cross reacting allergens.

Descriptive case study, focused on patients with selective gamba-allergy as
well as patients with a non-selective shrimp allergy. The first step is to
identify patients with selective gamba allergy on the basis of diagnostic
research (skin tests and oral provocation). This research takes place at the
Department of Allergology, Erasmus MC. the second step is to compare
sensitization patterns against gamba and shrimp proteins between patients with
selective gamba-allergy, respectively a non selective shrimp allergy. The
associated laboratory research takes place at Wageningen University & Research
Centre.

nvt

Group 1:

3 visits in the Hospital of which 1 x 1 hour and 2 x 5 hours

1st visit: inf concent signs, specific food history, blood collection, skin
prick test

2nd visit: 1st open provocation

3rd visit: 2nd open provocation



Group 2:

1 visit: 1 x 1 hour

Inf concent signs, specific food history, blood collection, skin prick test



At the skin test wheal may occur on the site of the prick, which, after some
hours disappears.

A blood collection (20 ml) usually gives no risks.

2 x open provocation (one with gamba and one with shrimp) on two different
days. After the last provocation the result will be discussed.

A provocation brings risks, but the risk for the patient will be limited given
the extensive experience in the field of Allergology at the outpatient clinic
with food provocations. The provocation starts at a very low dosage. (1 mg
scale animal protein) All the required facilities are provided (emergency
medication, adequate medical personnel). The provocation is carried out
according to international guidelines.