Also called basophilic leukocytes. A type of white blood cell that synthesizes and stores histamine and also contains heparin. When two IgE molecules of the same antibody “dock” at adjacent receptor sites on a basophil cell, the two IgE molecules capture an allergen between them. A chemical signal is sent to the basophil causing the basophil cell to release histamine, serotonin, bradykinin, and “slow-reacting-substance.” Release of these chemicals into the body causes the blood vessels to become more permeable which consequently causes the nose to run. These chemicals also cause smooth muscle contraction, resulting in sneezing, coughing, wheezing, etc.
A variety of white blood cell distinguished by the presence in its cytoplasm of coarse granules that stain purple black with Romanovsky stains. The function of basophils is poorly understood, but they are capable of ingesting foreign particles and contain histamine and heparin. There are normally 0.03-0.15 x 10⁹ basophils per liter of blood.