Leukocyte-promoting factor

Leukocyte-promoting factor, more commonly known as leukopoietin, is a category of substances produced by neutrophils when they encounter a foreign antigen. Leukopoietin stimulates the bone marrow to increase the rate of leukopoiesis in order to replace the neutrophils that will inevitably be lost when they begin to phagocytose the foreign antigens.^{[citation needed]}