Release of histamine from human basophils. Blood 1967;29:722–36

B ASOPHILS ARE THE least common of the normal circulating white blood cells, and studies concerning their composition and function have been very limited. It is known that basophils contain signfficant amounts of hista-mine ’ and that the granules in the cytoplasm give a characteristic meta-chromatic staining reaction similar to heparin. In the present work the histamine content of human basophils was estimated, using basophils ob-tained from normal blood donors and patients with chronic myeloid leukemia. Further, the isolated basophils were subjected to some experimental conditions known to release histamine from rat mast cells2’3-namely, freezing and thawing, suspension in distilled water, addition of the histamine release agents, protamine sulphate, compound 48/80 and eosinophil peroxidase, and finally an in vitro immune reaction involving antigen, antibody and complement. The amount of histamine released from basophils under these various conditions was determined. Phase microscope studies were also made of living basophils in order to establish any relationship between phagocytosis, granule lysi