Basophils

Basophils are a type of white blood cell, produced in the bone marrow and when needed by the body, enter the circulatory system already mature. Although they make up only 0.1% of the cells involved in an allergic reaction, basophils play a key role in the immune response process. They help the mast cells by releasing additional amounts of histamine during the occurrence of allergic reactions and contribute to their severity.

Basophils bind IgE (immunoglobunlin E, the major antibody associated with immunological responses in the body) antibody very tightly. This bound antibody is responsible for the selective response of basophils to such allergens as pollens. Basophils may also play a role in how T cells respond in a secondary immune response.