Basophil activation

Allergic symptoms are caused by an initial systemic histamine release by activated basophils and mast cells, that may lead to shock with laryngeal edema, lower-airway obstruction and hypotension.

Basophils contain many granules inside the cell, which are filled with a variety of active substance triggering an allergic response upon degranulation.

The cells are activated and start degranulation when the IgE antibody, bound to an allergen which can bind to the specific variable region of the IgE, the Fab region, bind to the Fc receptor In most cases, a positive skin test is used in identification of allergies, but the activation of basophilic granulocytes with anti-IgE, the expression of the CD63 antigen on the cell surface (plasma membrane) allows identification of the allergen responsible for the hypersensitivity reaction without performing the common scratch test.

The blood sample is added and the tube is incubated at 37 °C for several minutes, to ensure that the allergens can bind to the IgE.

Several minutes at room temperature gives the marker time to bind to the CD63 proteins on the cell membrane of the basophil.