What is a White blood Cell Count?
White blood cells (WBC) play a vital role in your immune system. They are also known as leukocytes. They assist in fighting infection and help in defence against other foreign materials. A white blood cell count is the number of white blood cells in your blood.
When you fall sick, your body produces more white blood cells to fight the bacteria, virus
or other foreign invaders causing the disease. This elevates your white blood cell count.
Some diseases can make fewer white blood cells than your body needs. This lowers your white blood count. They include some types of cancer and HIV/AIDS, a viral disease that attacks white blood cells. Certain medicines and therapies – chemotherapy, may also lower your white blood cells count.
WBC is the biggest cell type found in the blood and, while they vary in size, they are the largest cell type found in the blood. White blood cells may be found all over the body, including the lymphatic system and the blood. They constitute less than 1% of total blood volume. The lifespan of a white blood cell ranges from 18 hours to many years.
What are the types of WBCs?
Let us understand the different types of white blood cells and their functions.
There are five distinct types of white blood cells include:
|Types of WBCs (leukocytes||Functions|
|They kill and digest bacteria and fungi. When an illness develops, they are the most prevalent form of white blood cell and your first line of defence.|
|Lymphocytes (B and T)
|They generate antibodies to fight against bacteria, viruses and other foreign substances. They exist in two forms: B cells and T cells. B and T cells, in contrast to other white blood cells that offer non-specific immunity, have specific functions.
T cells are responsible for immediately eliminating foreign substances that they identify. T cells with ‘memory’ recall an invader after infection and respond fast if detected again.
B lymphocytes are essential while testing the efficacy of several modern vaccinations. T cells are the major participants in TB and pertussis vaccinations.
|Monocytes||Monocytes possess a longer lifespan than other white blood cells and aid in the breakdown of bacteria. They make up from 5- 12% of the white blood cells in your circulation. Their primary purpose is to remove dead cells from the body.|
|Eosinophils||Eosinophils are also involved in the battle against germs. They are also crucial in reacting to parasitic diseases (such as worms). They comprise no more than 5% of the white blood cells in your circulation. The digestive system has more eosinophil count. They are known for their role in allergic reactions and symptoms.|
|Basophils||Basophils are one of the numerous types of white blood cells found in the human body. These blood cells account for less than 1% of all circulating white blood cells and are the least common in all animals. Basophils are immune system cells, produced in the bone marrow. They play an important role in Asthma.|
How WBCs are formed?
Hematopoiesis is the process through which white blood cells are generated in the bone marrow. All blood cells are descended from the same Hematopoietic Stem Cell (HSC), also referred to as a ‘pluripotent’ stem cell. These stem cells develop (or specialise) at various stages.
The HSC cell first divides into a lymphoid or a myeloid stem cell.
The lymphoid cell line is derived from the lymphoid stem cell. This is the cell type that gives rise to B and T cells.
Myeloblasts are cells that develop from myeloid stem cells. These cells progress to become macrophages, monocytes, neutrophils, basophils and eosinophils. Red blood cells and platelets can be formed from myeloblasts.
What are the levels of WBCs in your blood?
Ucsfhealth says Normal white blood cell counts are:
Newborns – 9,000 to 30,000/mm3
Children less than 2 years of age – 6,200 to 17,000/mm3
Children more than 2 years of age and adults – 5,000 to 10,000/mm3
Higher-than-normal test results may indicate that you have an infection or sickness that your body is fighting. Lower-than-normal test results may indicate that your immune system is not operating as effectively as it should. This implies that even a little illness might result in major health complications.
What are the factors affecting WBC count?
White blood cell counts can be affected by a variety of illnesses and conditions, including:
- Your Immune system gets weakened: This is frequently induced by disorders like HIV/AIDS or cancer therapy. Chemotherapy and radiation therapy, for example, can kill white blood cells, putting you at risk of infection.
- Infection: A higher-than-normal white blood cell count is an indicator of illness. White blood cells are rapidly proliferated in order to eliminate the bacteria or virus.
- Myelodysplastic syndrome (MDS): This disease results in abnormal blood cell production. This comprises bone marrow white blood cells.
- Blood cancer: Cancers such as leukaemia and lymphoma can cause an abnormal form of blood cells to develop an uncontrollable rate in the bone marrow. As a result, the risk of infection or serious bleeding is considerably more.
- Myeloproliferative disorder: This illness refers to a group of disorders that cause an excess of immature blood cells to be produced. This can lead to an undesirable balance of all types of blood cells in the bone marrow as well as an excess or deficiency of white blood cells in the circulation.
Chronic myeloproliferative diseases are classified into six types: chronic myelogenous leukaemia (CML), polycythemia vera, primary myelofibrosis, essential thrombocythemia, chronic neutrophilic leukaemia and chronic eosinophilic leukaemia. Chronic myeloproliferative diseases can progress to acute leukaemia, which occurs when the body produces an abnormally large number of white blood cells.
- Medicines: Some medications have the ability to increase or decrease the body’s white blood cell count.
- High white blood cell numbers can be induced by conditions such as excessive physical stress caused by an injury or mental stress. Inflammation, childbirth or the end of a pregnancy, smoking or even excessive exercise can all be harmful.
Humans require a sufficient number of white blood cells. A low count can be a sign of an illness. A high white blood cell count is usually associated with an infection or disease. The white blood cell count test may be required to determine whether you have an infection or sickness. If you have a weakened immune system as a result of medicine or sickness, you may need this test to determine if your white blood cell count is too low. If it is, even a minor illness can be extremely harmful to your body.