They are elevated, also, during recovering lobar pneumonia, acute rheumatic fever and anaphylactoid purpura. They are decreased in the acute phases of the same conditions. Basophils are the precursors for mast cells. Mast cells are in tissues and, when adequately stimulated by allergens, cause the release of histamine, heparin and serotonin. More detail may be obtained by reviewing the lectures on immunity in BIOL 251.
Basophils are the same size as eosinophils, but have purplish to blue-black granules.
Agranular WBC also come from red bone marrow, but require further maturation in lymphoid tissue. They have NO granules. They have spherical nuclei and include lymphocytes and monocytes . They take longer than neutrophils to get to the damaged site, but arrive in greater numbers and destroy more organisms. Monocytes are also phagocytic and clean up cellular debris following an infection.