Neutrophil Granulocyte

Neutrophil granulocytes are generally referred to as either neutrophils or polymorphonuclear neutrophils (or PMNs), and are subdivided into segmented neutrophils (or segs) and banded neutrophils (or bands). Neutrophils are the most abundant type of white blood cells in mammals and form an essential part of the innate immune system. They form part of the polymorphonuclear cell family (PMNs) together with basophils and eosinophils.[1][2][3])

The name, neutrophil, derives from staining characteristics on hematoxylin and eosin (H&E) histological or cytological preparations. Whereas basophilic white blood cells stain dark blue and eosinophilic white blood cells stain bright red, neutrophils stain a neutral pink. Normally neutrophils contain a nucleus divided into 2-5 lobes.

Neutrophils are normally found in the blood stream. During the beginning (acute) phase of inflammation, particularly as a result of bacterial infection, environmental exposure,[4] and some cancers,[5][6] neutrophils are one of the first-responders of inflammatory cells to migrate towards the site of inflammation. They migrate through the blood vessels, then through interstitial tissue, following chemical signals such as Interleukin-8 (IL-8), C5a, and Leukotriene B4 in a process called chemotaxis. They are the predominant cells in pus, accounting for its whitish/yellowish appearance.

Neutrophil granulocytes have an average diameter of 12-15 micrometers (µm) in peripheral blood smears. When analyzing a pure neutrophil suspension on an automated cell counter, neutrophils have an average diameter of 8-9 µm.

With the eosinophil and the basophil, they form the class of polymorphonuclear cells, named for the nucleus's characteristic multilobulated shape (as compared to lymphocytes and monocytes, the other types of white cells). Neutrophils are the most abundant white blood cells in humans (approximately 10^11 are produced daily) ; they account for approximately 70% of all white blood cells (leukocytes).

The stated normal range for human blood counts varies between laboratories, but a neutrophil count of 2.5-7.5 x 109/L is a standard normal range. People of African and Middle Eastern descent may have lower counts, which are still normal.

A report may divide neutrophils into segmented neutrophils and bands.

A minor difference is found between the neutrophils from a male subject and a female subject. The cell nucleus of a neutrophil from a female subject shows a small additional X chromosome structure, known as a "neutrophil drumstick".

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