They are prominent at sites of allergic reactions, and with parasitic infections. Eosinophil secretory products inactivate many of the chemical mediators of inflammation. This phenomenon is most obvious with mast cell-derived mediators. Basophils These are slightly smaller than neutrophils and have a multilobed nucleus. Basophils contain metachromatically staining cytoplasmic granules.
Basophils are weakly phagocytic and sluggishly motile.
Their kinetics are not well defined but are probably similar to neutrophils. Basophils are the circulating counterpart of mast cells, and are often associated with certain allergic reactions and parasitic infections. Their major inflammatory function is release of basophil granule contents that incite vascular changes at sites of acute inflammation. Increased numbers of basophils are located in skin affected with ectoparasites. Increased numbers of circulating basophils are associated with heartworm infections in dogs.