Functional and phenotypic diversity of neutrophils in the bone marrow. Neutrophils are produced inside of the bone marrow (BM) through progressive maturation of hematopoietic progenitors (long-term hematopoietic stem cells [LT-HSCs] to GMPs). Proliferative precursors (NeP and preNeu) differentiate into immature neutrophils and finally into mature neutrophils that are released into blood. A fraction of aged neutrophils return into the marrow after several hours in the circulation. Top and bottom panels indicate specific phenotypes and functions, respectively, of neutrophils at each stage of their life cycle. HSC, hematopoietic stem cell; HSCT, hematopoietic stem cell transplantation; HSPC, hematopoietic stem and progenitor cell; MPP, multipotent progenitor; ST, short-term; TNF, tumor necrosis factor. Professional illustration by Patrick Lane, ScEYEnce Studios.