Physicians refer to the largest subgroup of white blood cells, the so-called leukocytes , as neutrophilic granulocytes . As phagocytes or “scavenger cells” they are part of the innate immune system of the human body. They identify and destroy harmful microorganisms in the body.
Neutrophils –
the largest group in the White Guard
Neutrophilic granulocytes are visible in the differential blood count as rod-nuclear or segmented neutrophils.
Formation and morphology of neutrophilic granulocytes
In one day, an adult produces over 1011 neutrophils. They are formed in the bone marrow, where they arise from oligopotent myeloid stem cells (CMP).
The oligopotent stem cells, which have the potential to give rise to different cells , develop into uni- or bipotent stem cells that come together to form cell colonies.
Young neutrophils are characterized by a rod-shaped nucleus. They are present in both blood and bone marrow, where they come from. Physicians call mature neutrophils segmented neutrophils because of their three to five core segments.
The neutrophilic granulocytes leave the bloodstream after six to eight hours if they do not come into contact with infections or inflammatory reactions. Normally they live for one to four days.
Neutrophils are spherical in shape, 12 to 15 microns in diameter. Doctors call them “neutrophilic” because the granular deposits of these granulocytes cannot be stained with basic or acidic dyes. Coloring occurs in the so-called basophils and eosinophils.
Purpose and normal value of neutrophilic granulocytes
Neutrophils circulate in the blood and migrate to the site of infection if one is present. At the scene, they absorb the infection-causing microbes through phagocytosis and destroy them by digesting the cell structure. Attractants called chemokines cause the neutrophils to leave the bloodstream to reach the infected tissue.
The normal value is three percent of the leukocytes for rod neutrophils and 45 to 70 percent for segmented neutrophils.
When are neutrophil counts elevated?
If there are too many neutrophilic granulocytes in the blood, doctors speak of neutrophilia. Possible triggers for this situation are:
- Elevated glucocorticoid levels resulting from exogenous administration of the steroid or as a symptom of Cushing’s syndrome,
- acute inflammation, sepsis or necrosis,
- surgical intervention to remove a focus of inflammation or wound drainage,
- chronic purulent inflammations such as pyometra, pyoderma and abscesses,
- Bleeding and, as a result, anemia, the so-called anemia,
- chronic granulocytic leukemia , in which mainly immature neutrophils are found in the blood.
Emotional stress and physical strain are also causes of neutrophilia, as the release of adrenaline induces neutrophil maturation. Neutrophilia can also occur during pregnancy .
When are neutrophil counts low?
Doctors call a reduction in the values for neutrophilic granulocytes neutropenia . A healthy person has 1,800 to 8,000 neutrophils per microliter. If the value drops to 1,000 per microliter, there is talk of a mild form of neutropenia. 500 to 1,000 per microliter is a moderate form of neutropenia and less than 500 per microliter is severe. Causes of neutropenia lie in:
- damage to the bone marrow by drugs, chemicals or plants, as well as infections or immune disorders,
- the increased consumption due to an acute serious illness such as sepsis or peritonitis,
- the disturbed formation of neutrophilic granulocytes due to myeloid leukemia or viral infections such as AIDS,
- congenital Kostmann syndrome.
The laboratory values are to be interpreted by the treating doctor in connection with other symptoms and previous illnesses as well as other blood values.
published by: Anna Nilsson ,
Links
- Reinhard Andreesen, Hermann Heimpel: Clinical hematology. Munich 2009: Urban & Fischer/Elsevier-Verlag. ISBN-10: 343731498X.
- Article on wikipedia.de https://de.wikipedia.org/wiki/Neutrophiler_Granulocyt
