Neutropenia

Medical Author:

Melissa Conrad Stöppler, MD

Melissa Conrad Stöppler, MD

Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.

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Medical Editor:

Mary D. Nettleman, MD, MS, MACP

Mary D. Nettleman, MD, MS, MACP

Mary D. Nettleman, MD, MS, MACP is the Chair of the Department of Medicine at Michigan State University. She is a graduate of Vanderbilt Medical School, and completed her residency in Internal Medicine and a fellowship in Infectious Diseases at Indiana University.

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"Neutropenia" is a condition in which the number of neutrophils in the bloodstream is decreased. Neutrophils are a type of white blood cell also known as polymorphonuclear leukocytes or PMNs. Neutropenia affects the body's ability to fight off infections.

White blood cells are also known as leukocytes. There are five major types of white blood cells:

1. basophils,
   
   
2. eosinophils,
   
   
3. lymphocytes (T-cells and B-cells),
   
   
4. monocytes, and
   
   
5. neutrophils.

Some white blood cells, called granulocytes, are filled with microscopic granules that are little sacs containing enzymes (compounds that digest microorganisms). Neutrophils, eosinophils, and basophils are all granulocytes and are part of the innate immune system with somewhat nonspecific, broad-based activity. They do not respond exclusively to specific antigens, as do the lymphocytes (B-cells and T-cells).

Neutrophils contain enzymes that help the cell kill and digest microorganisms it has engulfed by a process known as phagocytosis. The mature neutrophil has a segmented nucleus (it is often called a 'seg' or 'poly'), while the immature neutrophil has a band-shape nucleus (it is called a band). Neutrophils are made in the bone marrow and released into the bloodstream. The neutrophil has a life-span of about three days.