Neutrophils

Neutrophils are the most abundant type of white blood cells in most mammals and form an essential part of the immune system. They are formed from stem cells in the bone marrow. Neutrophils are classified as granulocytes due to the presence of granules in their cytoplasm, and they are also referred to as polymorphonuclear leukocytes (PMN or PML) because of the varying shapes of the nucleus.

Function

Neutrophils are a type of phagocyte and are normally found in the bloodstream. During the beginning phase of inflammation, particularly as a result of bacterial infection, environmental exposure, and some cancers, 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, fMLP, Leukotriene B4 and H2O2 in a process called chemotaxis.

Life cycle

The average lifespan of inactivated human neutrophils in the circulation has been reported by different approaches to be between 5 and 90 hours.

Clinical significance

Neutrophils are implicated in many forms of autoimmune diseases, and their presence in certain types of cancer may be a sign of a poor prognosis. They are also involved in the pathogenesis of many other inflammatory diseases such as rheumatoid arthritis and lupus.

See also

• Leukocyte
• Granulocyte
• Phagocyte
• Inflammation
• Autoimmune diseases

References

Neutrophils Resources
Latest articles Most recent articles Ongoing trials	Wikipedia