What are White Blood Cells?
Countries have a military system to guard their country against invading nations. The defence system is responsible for keeping their nation’s people safe. Corporate buildings have security guards to maintain a disciplined system of entry and exist. Likewise, our body contains certain defence mechanisms for certain cells to enter or exit the body.
WBCs, or White blood cells, are an important part of the body which plays a vital role in the defence mechanism. These cells protect the body against infections and invading pathogens. These cells also fight infections and other pathogens.
White blood cells account for about 1% of the total blood cells. However, they play a very big part in the body’s immune system. White blood cells are also called leukocytes.
These white blood cells are always at war and protect the body against invading bacteria, viruses and other pathogens. White blood cells are produced in the bone marrow and stored in the blood and lymph tissues. The bone marrow continuously produces these cells, as some types of white blood cells have a short life span.
There are two types of defence systems the body uses to defend itself.
- Innate immunity and
- Adaptive immunity
Innate immunity acts as the body’s first line of defence and is also called as a non-specific immune response. The immune response will be quick, and the invading pathogen that enters the body will be detected and eliminated within a few hours.
Innate immunity protects the body when pathogens invade the skin and mucous membranes.
Innate immunity activates or alerts the defence mechanism of the body if the pathogens escape the first line of defence.
When the pathogens escape the first line of defence, adaptive immunity identifies and destroys the pathogens. Adaptive immunity specifically targets those pathogens which causes the infection and eliminates them.
Adaptive immunity responds slowly; however, they are always specific. Adaptive immunity contains memory cells. When the same organism invades the body, these memory cells remember them and eliminate the pathogens the same way they did earlier.
Adaptive immunity contains T cells, antibodies and B lymphocytes. This blog will discuss the white blood cells types and their functions.
Types of White Blood Cells
The types of white blood cells are
Monocytes have the longest lifespan when compared to other cells. Monocytes are produced in the bone marrow and makeup about 2-8% of the leukocytes. Once they mature, they travel through the bloodstream to other tissues and become macrophages or dendritic cells (DC).
Macrophages’ defence mechanism is to surround the invading pathogen and engulf them. They remove the dead cells and help boost immune response.
Dendritic cells are also called antigen-presenting cells (APCs). The cells identify the invading pathogens and present them to the other immune cells to remove the pathogens from the body.
Monocytes are a component of innate immunity. The main two functions of the monocytes are
- Circulate throughout the body and check for microbial infection.
- Plan an immune response in times of infection and inflammation.
Monocytes play an important role in the inflammatory and anti-inflammatory processes that take place during an immune response and in disorders like myelodysplastic syndromes and leukaemia.
According to NCBI, monocytes play a crucial role in immune responses like mycobacterial infections and varicella-zoster virus.
Monocytes contain toll-like receptors that interact with the pathogen-associated molecular pattern (PAMPs). These PAMPs are found in the invading pathogens.
When pathogens enter the body, they send a certain signal that activates the monocytes. In response to the signal, the monocytes from the bone marrow migrate and enter the bloodstream. The monocytes in the bloodstream infiltrate these pathogens within 12-24 hours.
Lymphocytes are responsible to produce antibodies that help fight against invading microorganisms. The lymphocyte is an umbrella term. T cells, B cells, and natural killer cells together are called lymphocytes.
The lymphocytes play an important role in adaptive immunity. The T cells are produced in the thymus, and the B cells are in the bone marrow. The cells got their names from the organ they produced.
The cells are produced in the primary lymphoid organs like the thymus and bone marrow. Then they mature in the secondary lymphoid organs like the lymph nodes and the spleen.
The T and B cells get activated and morphologically get activated when a pathogen enters the body.
These cells are slightly bigger than the red blood cells. When activated, they get mature into the effector cells.
The T cells are categorised into two types— helper T cells and cytotoxic T cells. The helper T cells activate the macrophages, effector T cells and B cells. The cytotoxic T cells kills the targeted pathogens.
The neutrophils are the most abundant cell type in the bloodstream. These neutrophils are produced in large numbers by the bone marrow. When the neutrophils complete their function, they are eliminated by the macrophages.
The main functions of neutrophils include
- Phagocytosis (engulfing)
- Degranulation (release of cytoplasmic granules).
Basophils are a type of white blood cell that fights against pathogens and keep you healthy. Basophils are produced in the bone marrow, and they circulate throughout the body.
Basophils are produced during an allergic reaction. Basophils are a type of granulocytes. Basophils are very the least abundant cells in circulation.
The lifespan of the basophils is very short— 1-2 days.
On average, eosinophils make up about 1-4% of the total leukocytes. The eosinophils are mainly involved in chronic inflammation, and allergic reactions against parasitic infections and other invading pathogens.
Additionally, they modulate the effects of inflammatory vasoactive mediators. The modulatory effect is specific against the substances like histaminase and arylsulfatase. Also, against enzymes that decompose the histamine and leukotrienes.
According to NCBI, eosinophils help fight against parasitic infections by releasing their specific granules. These granules contain cationic protein, majorly of basic protein that can exhibit toxicity against helminth parasites. Lastly, like neutrophils and basophils, eosinophils are phagocytic. However, they are commonly involved in cleaning out the antigen-antibody complexes.
Functions of White Blood Cells
The primary role of white blood cells is to fight against invading micro-organisms and protect the body against these infections. The other functions are listed below.
- Leukocytes or white blood cells participate in innate and humoral immunity.
- White blood cells circulate throughout the body and initiate an inflammatory and cellular response to the injured organ or pathogens.
- They migrate to the site of infection or injury, which is mediated by pathogen-associated molecular patterns (PAMPs).
- The cells also migrate to the damaged tissues through damage-associated molecular patterns (DAMPs), which are specifically signalled by the microbes.
- When the pathogen is detected, white blood cells release cytokines as a signal, which makes the leukocytes migrate out of circulation and reach the site of infection.
- The endothelial cells secrete chemoattractant that help with the adhesion of white blood cells to the pathogens
Normal WBC counts
According to NCBI, the normal white blood cell count should be in the range of 4,000-11,000 per micro litre. However, the range can differ from one lab to another depending on the handling techniques and errors.
Low white blood cell count
A low white blood cell count is called leukopenia. A count range that is less than 4,500 cells per micro litre is considered low white blood cells.
Low white blood cells are caused due to bone marrow disorders, autoimmune diseases, and other terminal illnesses like cancer and HIV.
Some of the common symptoms of low blood cell count include
- Sore throat
- Severe cough
- Unusual vaginal discharge
- Mouth sores
- Fever and chills
- White patches near the mouth
- Painful urination
- Cuts that drain pus
The drugs that can lead to low white blood cells include
- Antithyroid drugs
- Chemotherapy drugs
- Histamine-2 blockers
A low blood cell count can be treated with growth factors. The drugs will help the bone marrow to produce more blood cells. These medication boosts the production of more white blood cells.
High white blood cell count
A high white blood cell count is called leukocytosis. A cell counts higher than 11,000 cells per micro litre is considered as leukocytosis. A high blood cell count can include the following conditions.
- Injury and
- Immune system disorders
In most cases, when the blood cells count increases, it can indicate that the body is fighting a certain infection or an invading pathogen. When the infection settles down, the white blood cell count will return to normal. However, in some cases, it can indicate certain health conditions.
What causes a high white blood cell count?
Some of the common causes that can lead to leukocytosis include
- Tissue damage
- Inflammatory diseases like allergy and rheumatoid arthritis
- Drugs and medications
- Spleen removal injury
- Tobacco Smoking
- Hodgkin disease
A high white blood cell can also be caused during pregnancy. The symptoms of high blood cell count include
- Difficulty breathing
- Unexpected weight loss
- Rash and
- Unexpected weight loss
Symptoms of an abnormal WBC count
An abnormal white blood cell count can indicate an infection or other health conditions.
Some of the common symptoms of abnormal white blood cell count include
- Allergy symptoms like runny nose, congestion and rash
- Decreased appetite
- Localised swelling at the site of infection
- Redness at the sight of infection
- Release of enzymes that lead to an increase in body temperature
- Blood vessels to leak or widen
How to prepare for a WBC count test
There is no specific preparation for white blood cell count. You can just consume normal food and go for your test.
The blood sample will be collected, and the blood drawn will be sent to the lab to process the collected sample, and the results will be given.
The treatment for abnormal white blood cell count can differ. If a person has a low white blood cell count, treatment will be given in such a way as to boost the low cell count.
Conditions affecting the white blood cells
Certain health conditions can affect the white blood cells and lead to abnormalcy. Some of the common health conditions are discussed below.
Aplastic anaemia is a condition that affects the production of white blood cells. This can cause fatigue and increases the risk of getting infected. Additionally, it can also lead to uncontrolled bleeding.
Aplastic anaemia is considered as a significant condition and also rare, which can occur at any age. This condition can occur suddenly and can worsen in a short period of time. This condition can be severe or mild.
Some of the symptoms of aplastic anaemia include
- Shortness of breath,
- Pale skin,
- Easy breezing and
- Frequent infections.
The condition is common among both men and women and equally distributed. However, there can be seen a small rise in the occurrence of the cases during childhood and between the age of 20-25.
The cause of the condition is still unknown, and according to NCBI, it affects about 0.6-6.1 cases per million population. Additionally, 5-10% of aplastic anaemia is caused due to seronegative hepatitis and telomerase defects also account for aplastic anaemia.
Evans syndrome is an autoimmune condition which leads to two or more types of anaemia (cytopenia). The commonly included anaemias are autoimmune haemolytic anaemia (AIHA) and immune thrombocytopenia (ITP). The condition can occur with or without these anaemias.
Evans syndrome is categorised into two types— primary and secondary. The cause of primary Evans syndrome is not known, and secondary Evans syndrome is caused due to an underlying health condition like lupus, common variable immunodeficiency (CVID), and autoimmune lymphoproliferative syndrome (ALPS).
The cause of Evans syndrome is still unknown. The condition is caused due to an autoimmune disease. The B cells produce antibodies that attack their own cells, like the red blood cells and white blood cells. This condition leads to a decrease in the white blood cell count.
According to NCBI, the condition is caused due to excessive immune dysregulation. Additionally, Evans syndrome is rare and is caused to about 5% of the patients affected with ITP or AIHA during their onset.
The condition is more prevalent in women when compared to men. It usually affects children; however, it can also occur in adults. Some of the common symptoms of Evans syndrome include
- Shortness of breath
- Limited physical activity
People with Evans syndrome can exhibit symptoms of jaundice when examined physically. Other symptoms include enlargement of the spleen, easy bruising, petechiae, and purpura.
The treatment for Evans syndrome can differ depending on the severity of the condition. A person with low red blood cells might require a transfusion.
The first line of treatment will be the administration of corticosteroids or immunoglobulin intravenously. However, the response to corticosteroid administration may differ from one patient to another.
According to NCBI, Evans syndrome can relapse, and half of the cases have been reported to relapse. So, it is crucial to make use of alternative treatments.
Low white blood cell count can also result due to the condition of HIV (human immunodeficiency virus). A decrease in low white blood rates can increase the risk of bacterial and viral infections like HIV and gonorrhoea.
These diseases are usually sexually transmitted. However, there are other modes of transmission, like the usage of the unclean syringe. According to NCBI, the mortality rate is higher.
When an infection occurs, the pro-inflammatory response is required for the host response, which is essential for protection. However, in the case of HIV infection sepsis is said to occur when reduces the ability of the leukocytes to respond to these infections.
According to NCBI, people with HIV can be affected by anaemia, leukopenia and thrombocytopenia. In some cases, anaemia can be presented as fatigue, weakness and shortness of breath. Other symptoms like easy bruising, fever and unexpected weight loss.
The diagnosis of HIV will require screening and a confirmatory test. The blood sample will be collected from the patients and will be assessed for certain antibodies or antigens.
The treatment of HIV will aim to reduce the viral load and maintain the CD4 count. There is no direct treatment for HIV. However, a combination of drugs will be given to treat HIV.
If patients are left untreated, it can develop as AIDS. The AIDS phase can be asymptomatic, and a rapid decline of CD4 cells can be seen. There is no cure for HIV or AIDS, and lifelong management of symptoms will be required.
Leukaemia is cancer that affects bone marrow and the lymphatic tissues. The bone marrow is responsible for producing white blood cells. There are many types of leukaemias, and some are common in children. These conditions can also affect adults.
Leukaemia causes excessive production of white blood cells that functions abnormally. These white blood cells die in a short span of time or will lead to an autoimmune disease. They also proliferate at an abnormal rate.
Some of the common risk factors associated with leukaemia include Down’s syndrome, Klinefelter syndrome, Bloom syndrome, ataxia telangiectasia and telomeropathies.
There are four major types of leukaemias include
- Acute lymphoblastic leukaemias
- Acute myelogenous leukaemias
- Chronic lymphocytic leukaemias
- Chronic myelogenous leukaemias
Some of the common causes that can lead to leukaemia are
- Exposure to ionising radiation.
- Exposure to chemotherapy.
- History of haematological malignancy.
- Viral infections.
- Exposure to benzene.
- Other genetic syndromes.
The treatment of leukaemia will depend on the type of leukaemia affected. Patients affected with acute leukaemia will require significant support, frequent monitoring and electrolyte imbalances. Some of the common symptoms of leukaemia include
- Recurrent nosebleeds,
- Night sweats,
- Bone pain,
- Unexpected weight loss,
- Fever and
- Swollen lymph nodes.
Primary myelofibrosis causes scar-like tissue in the bone marrow cells. This can lead to the underproduction of white blood cells.
These scar-like tissues can affect the production of red blood cells and platelets. It can also lead to abnormal proliferation of blood cells like platelets, white blood cells, and red blood cells.
This disorder is characterised by uncontrolled cell growth and can also lead to blood cancers. The most common symptoms of primary myelofibrosis affect the production of blood cells.
In some cases, there will be underdevelopment of red blood cells and abnormal shape. However, there can be asymptomatic cases.
Patients affected with primary myelofibrosis will commonly have enlargement of the spleen and liver.
The cause of primary myelofibrosis is unknown. The treatment of primary myelofibrosis will involve biotherapy. Biotherapy can help reduce the enlargement of the spleen and liver. Sometimes, chemotherapy and low doses of radiation may be given to reduce the enlargement of the spleen.
JAK2 inhibitors may also be used to block the activity of the JAK2 protein. They can be effective in patients with JAK2 mutation.
Primary myelofibrosis cannot be cured, and the disorder should be maintained for a lifetime. There are medications given to reduce the severity of the symptoms.
The severity of the symptoms can depend on one individual to another. The disorder usually affects people aged above 50; however, it can affect anyone of any age.
How to raise or lower white blood cell count?
White blood cell count can be raised with certain foods. People with low blood cell count should consume a good amount of protein. Some diet modifications will be required to increase the white blood cell count.
Additionally, supplements can be prescribed by your doctor to raise blood cell levels. Vitamin B12 and folate play an important role in boosting your white blood cells.
If you have a low white blood cell count avoid the consumption of raw milk, cheese and unpasteurised juice and other fried and fatty foods.
When to consult a doctor?
Consult your doctor if you have persistent symptoms like
- Fever and chills,
- Easy bruising,
- Excess bleeding,
- Poor appetite,
- Night sweats,
- Nausea and vomiting,
- Difficulty breathing,
- Chest pain,
- Abdominal pain,
- Unexpected weight loss and
A high white blood cell count can indicate certain infections, and it will settle after the infection is eliminated. However, in some cases, it can indicate major health illnesses and conditions like allergies and rheumatoid arthritis.
Sometimes medication can also cause an increase or decrease in white blood cells. In such cases, consult your doctor and do not stop any medication on your own.
Low white blood cells can also be caused due to bone marrow cancers and abnormal proliferation of white blood cells. These abnormalities can be avoided with a proper diet. Avoid smoking and alcohol consumption. These habits can increase the risk of an abnormal white blood cell count.
There are many medications and therapy available to treat abnormal white blood cell count. Proper diagnosis will be the first step to treating such diseases and conditions.
What happens if white blood cells are high?
If the white blood cell is high, the condition is called leukocytosis. It can indicate the person has an infection or emotional or physical stress. In some cases, it can indicate an autoimmune disease.
What is a normal white blood count?
According to NCBI, a normal white blood cell count range is 4,500 to 11,000 WBCs per micro litre.
What happens if white blood cells is low?
If the white blood cells are low, the body’s ability to fight infections reduces and lead to severe health conditions or diseases.
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