Neutrophils count in normal patient.. 40 - 75 %

Neutrophils count in normal patient:
a- 40 - 75 %***
b- 21- 40 %
c- 1-6%
d- 0 -1 %.

Neutrophilic or polynuclear neutrophils (PNN) (or simply "neutrophils") are blood cells belonging to the white line. These are white blood cells (leukocytes) that have a major role in the immune system.

Neutrophils are part of granulocyte or "polynuclear cells" cells. They are called polynuclear because of a historical error: by the plurilobed character of their nucleus (from two to five lobes in general), it was long believed that these cells had several nuclei. The other granulocytes are eosinophilic and basophilic granulocytes. The qualifier of "neutrophilic" also comes from a visible characteristic in optical microscopy: after adding usual vital dyes (May-Grünwald Giemsa or MGG), these cells remain neutral (they poorly fix acidic and basic dyes). Neutrophils alone represent around 65 % of all blood leukocytes, and 99 % of granulocytes.

The granules present in the cytoplasm of neutrophils contain toxic substances allowing the elimination of extracellular microorganisms such as bacteria or fungi. As with macrophages, the activation of the oxidative explosion (oxidative Burst) by neutrophils leads to the production of free radicals of oxygen and the secretion of hydrogen and hypochlorite peroxide. Neutrophils are the most numerous phagocytes, constituting 50 % to 60 % of all circulating leukocytes, and are among the first cells recruited from the infection site. The bone marrow of an adult healthy individual produces about 100 billion neutrophils per day, and about 10 times more during an acute infection.

The passage of neutrophilic polynuclear power in the blood is fast and in short because they play their role essentially in the tissues, where they are the main anti-bacterial cellular agent. The life of the neutrophilic polynuclear is very short because it is entirely consumed by its function, which contributes to making it an anti-infectious, absolutely non-specific cell; It can indeed fight a very wide variety of different threats.

Morphology:

Neutrophilic polynuclear is a spherical cell, having a nucleus segmented into several lobes which reflect light (because of the many granulations). It moves adherently on the wall of other cells by projecting extensions called Lamellipodes.

This mode of displacement is called amoeboid.

Functions:

It is the first cell mobilized by the immune system in the presence of a pathogen.

Neutrophils have a key role in phagocytosis when they meet a foreign or infected cell. Phagocytosis takes place just after stimulating the neutrophil by an antigen worn by the target cell (this antigen being most often a fragment of bacterial membrane or a fragment of viruses, recognized as a stranger) with the emission of pseudopods (long cytoplasmic extensions ) which will surround the target cell, and end up including it in the cellular body of the neutrophilic.

There, vacuoles contained in the neutrophils merge with the vacocytosis vacuole: their content (lysozyme and secretory granulations) destroys the target cell by a toxic mechanism. This process leads to the death of the neutrophile, because it exhausts all its glucose reserves.

Phagocytosis is favored by the mobility of these cells: they are capable of moving into the blood and then in the tissues towards hearths of infection, where they are attracted by chemotacticism (during an infection, endothelial, mastocytes and cells nearby macrophages release chemicals called cytokines, which attract polynuclear).

Neutrophils are much more numerous than other cells endowed with phagocytosis (macrophages), but survive in the blood much shorter. Some immune system specialists think that this short lifespan (which ends from the first phagocytosis) is an evolutionary adaptation which makes it possible to avoid the spread of pathogens capable of parasitizing phagocytes.

The lifespan of neutrophils was measured by means of white blood cells marked by radioactive isotopes. In traffic, neutrophils hardly live more than 10 to 12 hours. In the tissues, this lifespan seems to be longer (2 to 3 days). When a neutrophile leaves traffic, p. ex. To go to an inflammatory hearth, he never returns there again. When a neutrophile dies, its fragments are taken up by Phagocytosis in the S.R.E.

After new research, it seems that neutrophils have an unprecedented function in immune control. Indeed, they would have the ability to expel their own genetic material, towards the pathogen in order to neutralize them and degrade them more easily. It is netosis.

The properties of DNA are well known, very long molecule (when it condenses) and above all very sticky, its action on the parasites could work indeed. During the action of the neutrophils, they expel in the direction of bacteria (especially) a very viscous and very sticky substance, their DNA. The bacteria are thus stuck and they can no longer move, their destruction is easier.

In human pathology:

A drop in the absolute value of neutrophils is called "neutropenia". This can be congenital, or much more often linked to acquired factors (severe infection, chemotherapy, etc.).

Functional anomalies are most often hereditary: neutrophils can be incapable of phagocytosis.

Congenital alpha-1-antitrypsin deficit leads to a lack of inactivation of elastasis, one of the enzymes contained in neutrophils. Elastase is an enzyme capable of destroying certain tissues, and this disease causes tissue damage, especially in the lung (pulmonary emphysema). Smoking poisoning leads to an inhibition of alpha-1-antitrypsin which has the role of modulating the action of the elastases of neutrophils. This leads to an increased destruction of the elastic fibers of the lung which increases his compliance, causing an emphysema that hinders ventilatory mechanics.

Neutrophilic can be subject to various other anomalies, these anomalies can be transient such as toxic granulations, the presence of vacuole in the cytoplasm or the presence of döhle bodies often sign of an infectious or more serious state as the presence of hypersegmegen neutrophile (The nucleus contains 5 or more lobes).

Successive phases of neutrophilic hyperleukocytosis:

1- Mobilization of marginal and sequestrated granulocytes

This is what we see, for example after injection of adrenaline or following muscle exercise.

2- Large of reserves of the bone marrow

3- Transient hyperleucocytosis.

4- Hyperproduction of neutrophils by bone marrow

In this case, hyperleucocytosis is maintained in a sustained manner; The proportion of neutrophils often exceeds 80 %; There is always an appearance of young (monolobed) forms.