Anaphylactic shock is the most severe expression of immediate hypersensitivity reactions. The mechanisms leading to these reactions are still poorly understood and may involve platelets, especially in the most severe forms.

The IgE ( ImmunoglobulineE)-mediated mechanism, involving the FcERI(the high-affinity receptor for the Fc region of immunoglobulin E (IgE) receptor present on the surface of mast cells and basophilic cells, is the most common mechanism. The receptors FcERI and FcERII are also described as being present on the surface of blood platelets, which would imply their activation along with the other cells involved. However, studies showing the presence of the FcERI/RII receptors on blood platelets suffer from many biases.

The main objective of the research is to study whether the FcERI/RII receptors are present and functional on the surface of blood platelets from allergic patients.

Inclusion Criteria:

• Age > 18 years-old
• With a protein/drug allergy (hymenoptera, arachide, amoxicillin)
• Confirmed by skin tests and/or challenge test
• With specific IgEs

Exclusion Criteria:

• Patients who refuse to participate to this study
• Patients unable to consent

Patients assessed in the allergy clinic of the Strasbourg University Hospital