Polymorphonuclear leukocyte

Polymorphonuclear leukocytes (PMNs, PML, or polymorphonuclear neutrophils) are a type of white blood cell in the immune system. They are named for the varying shapes of the nucleus, which is usually divided into multiple segments. PMNs are the most abundant type of granulocyte. They are referred to as either neutrophils or polymorphonuclear leukocytes, although these terms can also refer to white blood cells with a one-lobed nucleus (such as monocytes and lymphocytes).

Function

PMNs play an essential role in the body's defense against bacteria. They are the first cells to arrive at the site of an infection, where they engulf and destroy the bacteria through a process called phagocytosis. PMNs also release enzymes and antimicrobial peptides that kill bacteria.

Structure

PMNs are characterized by the presence of granules in their cytoplasm. These granules contain enzymes and other substances that are used to kill and digest microorganisms. PMNs have a multi-lobed nucleus, which distinguishes them from other types of white blood cells.

Clinical significance

Abnormalities in the number or function of PMNs can lead to disease. For example, a decrease in the number of PMNs (neutropenia) can result in an increased susceptibility to infections. On the other hand, an increase in the number of PMNs (neutrophilia) can be a sign of an ongoing infection.

See also

• Neutrophil granulocyte
• White blood cell
• Granulocyte
• Phagocytosis

References

Polymorphonuclear leukocyte Resources
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