Cytokines promoting the proliferation and differentiation and of neutrophils include IL3, IL6, G-CSF, and GM-CSF, the last two of which serve as the primary regulators of granulopoiesis.
Neutrophils are produced in large numbers, survive a short time and production is up-regulated in response to inflammation or infection.
Following mitosis progenitors mature to neutrophils in the bone marrow over several days.
The marrow reserve exceeds circulating neutrophils are 5-10 fold.
Neutrophils released from the bone marrow reserve is the main contributor of acute leukocytosis.
Circulating granulocytes circulate for a variable period of time and then enter tissues.
Daily white blood cell production is in the range of 10 to the 10th to 10 to the 11th .