Polymorphonuclear cell (PMN)

Polymorphonuclear cells (PMNs), also known as granulocytes, are a category of white blood cells characterized by a multi-lobed nucleus and the presence of cytoplasmic granules (Massive Bio, 2026). This group primarily includes neutrophils, which are the most abundant, as well as eosinophils and basophils (Quora, 2020). PMNs serve as the primary effectors of the innate immune system and the first line of defense against bacterial and fungal infections through mechanisms such as phagocytosis, degranulation, and the formation of neutrophil extracellular traps (NETs) (NIH, 2026). While essential for host defense, dysregulated PMN activity contributes to the pathogenesis of various conditions, including chronic inflammation, sepsis, and autoimmune diseases (Frontiers in Immunology, 2026). Therapeutic strategies targeting PMNs focus on modulating their recruitment to tissues, suppressing excessive activation, or enhancing their clearance to prevent collateral tissue damage (NIH, 2026). Additionally, PMNs are increasingly recognized for their complex roles in the tumor microenvironment, where they can exhibit both pro-tumorigenic and anti-tumorigenic activities (ASH Publications, 2001).

Other names

Polymorphonuclear leukocyteGranulocytePMNLPolymorphonuclear neutrophil

Modulation of cell recruitment, activation, effector functions (e.g., ROS production, degranulation), or survival/apoptosis.