White cells in blood

One important component of the body’s defence system is the neutrophil, a type of white blood cell in the blood.

MY aunt, who has been on cancer chemotherapy, was recently admitted because of fever. She was told she has low white blood cell count. The doctor said this is neutropenia. What is neutropenia?

Neutropenia means an abnormally low number of neutrophils in your bloodstream. (Neutro for “neutrophils”, penia = low.)

A neutrophil is a particular type of white blood cell that specialises in fighting off infection.

Some drugs may lead to decreased levels
of neutrophils (a type of white blood cell)
in the blood. - Photos.com

What are white blood cells are how many types are there? I thought blood is of a red colour.

Your blood is red because of the haemoglobin in it. The cells in your blood are predominantly made of red blood cells, which carry oxygen, but there are a certain number of white blood cells (leukocytes) that must be present in your bloodstream. These are part of your body’s immune system.

The density of leukocytes in your bloodstream is 5,000 to 7,000 cells every square mm.

There are several types of white blood cells:

Neutrophils – these form 50% to 70% of all white blood cells. They literally “eat” bacteria in a process called phagocytosis, in which they surround the bacteria and take it into their own cellular material.

You can actually see them in wounds that have a lot of pus.

After ingesting a few bacteria, they die.

Eosinophils – these reddish cells specialise in phagocyting parasites. They form only 2% to 4% of white blood cells.

Basophils – these are the rarest of the white blood cells, present in only 0.5% to 1%. They secrete substances like anti-clotting factors and histamines. Their main function is in the hypersensitivity reaction.

Lymphocytes – these form 20% to 40% of the cells. They are also present in your spleen, lymph nodes, thymus, tonsils and other lymphoid tissues. They are the main aggressors of the immune system because they secrete antibodies that bind to viruses and bacteria to nullify them so the neutrophils can later ingest them easily.

Lymphocytes also have a “memory” of the bacteria and virus forever, so when the same bacteria or virus attacks you, the lymphocytes will be able to mount a rapid response.

This is called “being immune” to the disease.

Monocytes – these form 3% to 8%. They play a role in phaygocytosis as well as secreting interferons and other substances.

Neutrophils leave the blood stream after six to eight hours and enter the tissues, where they either stay in the cells or die.

Is neutropenia caused only by chemotherapy?

Neutropenia can exist in normal healthy populations. Certain black people and Yemenite Jews have it. But in most people, neutropenia is a bad sign.

Neutropenia can be caused by any disease that:

·Decreases the production of white blood cells by the bone marrow – these include drugs (for example, chemotherapy); diseases of the bone marrow (for example, leukaemia); infections which suppress the bone marrow (viral diseases, TB); vitamin deficiencies.

·Destroys the white blood cells quickly after they are produced and released – when antibodies attack the white blood cells (Felty’s Syndrome); certain drugs that stimulate antibodies to attack its own white blood cells.

·Causes the accumulation or pooling of white blood cells, which takes them out of the blood stream (with some overwhelming infections, during haemodialysis, during heart-lung bypass surgery.)

How low does your white blood cell count need to go to be classified as neutropenia?

The normal white blood cell count is 4,500 to 10,000 white blood cells per microlitre. Neutrophils will form 50% to 70% of that. When your absolute neutrophil count (ANC) is 1,000 to 1,500 cells per mm3, it is mild neutropenia.

When your ANC is 500 to 1,000 cells per mm3, it is classified as moderate neutropenia. When your ANC is less than 500 cells per mm3, it is severe neutropenia.

What happens if you have neutropenia?

Because neutrophils are needed for your immune system and body defence, if you have neutropenia, then you can have infections.

The most common site for infections due to neutropenia begin with your mucous membranes, such as your lips, mouth, and eyes. The second most common infection site is your skin. This presents as ulcers, abscesses, rashes and delay in wound healing.

You have to be especially vigilant to look out for these if you have neutropenia because the normal signs of infection like warmth and swelling may not be present. This is because neutrophils are needed to mount a normal response, and if you have neutropenia, you will not have a normal response.

Note that people with neutropenia are not at increased risk for viral or parasitic infections because these are taken care of by the lymphocytes and eosinophils.

Serious infections can result in fever. This condition is then called febrile neutropenia. This is a potentially dangerous condition that can result in widespread infection.

There are drugs called the granulocyte-colony-stimulating factors to help boost your neutrophil count.

# Dr YLM graduated as a medical doctor, and has been writing for many years on various subjects such as medicine, health advice, computers and entertainment. The information contained in this column is for general educational purposes only. Neither The Star nor the author gives any warranty on accuracy, completeness, functionality, usefulness or other assurances as to such information. The Star and the author disclaim all responsibility for any losses, damage to property or personal injury suffered directly or indirectly from reliance on such information.