Neutrophils

Author: V. Dimov, M.D., Allergist/Immunologist and Assistant Professor at University of Chicago
Reviewer: S. Randhawa, M.D., Allergist/Immunologist and Assistant Professor at NSU

Neutrophils, also called polymorphonuclear leukocytes (PMNs), are the most abundant circulating WBCs. PMNs mediate the earliest phase of inflammatory response.

Granulocytes are CD45+ CD15+ cells.

PMNs migration to tissues

CXCL8 (IL-8) forms a chemotactic gradient that directs leukocytes towards site of tissue injury/infection. Neutrophils are activated by cytokines secreted by Th17 cells.

Neutrophils migrate into tissues via:

- IL-8
- LTB4
- IFNγ
- f-met-leu-phe (fMLP)
- C5a
- interactions between Sialyl-Lewis X, P-selectins and LFA-1/ICAM-1


Neutrophils extravasate from blood vessels to the site of tissue injury or infection during the innate immune response. Image source: Wikipedia, GNU Free Documentation License.

What is the PMN half-life?

6 hours. 100 trillion cells are produced every day by the BM.

What is the most important PMN enzyme?

Elastase.

PMNs do not stain either red (eosinophils) or blue (basophils).

Video: A neutrophil chasing bacteria, set to music. Phagocyte immunodeficiencies (click to enlarge the image): References Phagocyte deficiencies
Published: 06/28/2010
Updated: 07/16/2012