Let's learn about the little soldiers in your body - lymphocytes.

We all want to be healthy. So did you know that our body has an amazing defense system that protects us from diseases? Lymphocytes are very important members of that defense system. Simply put, they are like little soldiers in our body. Let's talk a little more about these lymphocytes today.

What exactly are lymphocytes?

Lymphocytes are a type of cell called white blood cells. Yes, you have heard that there are red cells and white cells in the blood. Lymphocytes are a special group of white cells. Their main function is to help our immune system. The immune system is like the defense army in our country. This system is there to protect us from enemies coming from outside (that is, from germs , bacteria, viruses that cause diseases).

There are two main types of lymphocytes:

• T lymphocytes (T cells): These are the ones who control the immune system's responses. They can also find infected cells and cancer cells and directly attack and destroy them.
• B lymphocytes (or B cells): These are the ones who make things called antibodies. Antibodies are a type of protein. To be precise, these are like weapons that are specially developed to recognize and fight against foreign invaders like viruses and bacteria.

So, what service do these lymphocytes provide to our bodies?

Lymphocytes are not just a few cells. They perform a great service for our bodies.

Mainly, these lymphocytes help fight cancer cells and fight antigens such as viruses and bacteria from outside.

Not only that, but these lymphocytes also have an amazing memory. They remember every antigen they encounter. Imagine, if you had measles as a child , you will get measles again very rarely when you grow up, right? The same goes for chickenpox. That is because of the memory of these lymphocytes. Some lymphocytes, after encountering an antigen, become “memory cells”. Then, if the same antigen comes into the body again, these memory cells quickly recognize it and respond quickly. That is why we do not get some diseases twice. It is because of this principle that we can be protected from some diseases by giving vaccinations.

How do T cells and B cells work?

These T cells and B cells both work together, but their roles are slightly different.

The role of T cells

T cells are mainly responsible for destroying infected cells and controlling our body's response to foreign substances. However, many T cells need the help of another immune cell to function. Once T cells are activated, they multiply (that is, increase in size) and specialize into different types of T cells. These types are:

• Cytotoxic T cells: These are like special forces on the battlefield. These cells attach to antigens on infected or abnormal cells. They then make holes in the cell membrane of the infected cells, inject enzymes , and kill them.
• Helper T cells: As the name suggests, these help other immune cells. Some help B cells make antibodies. Others help cytotoxic T cells activate.
• Regulatory T cells: These cells produce substances that help end an immune system response. Sometimes, they also help prevent our own body from having harmful reactions.

The function of B cells

B cells have special receptors on their surface that bind to antigens. B cells learn to recognize these different antigens and produce specific antibodies to attack each one. B cells respond to antigens in two ways:

• Primary immune response: When an antigen comes in contact with a receptor, B cells are stimulated. Some B cells become “memory cells.” Other B cells become “plasma cells.” These plasma cells make antibodies that are specific to the antigen that was stimulated. However, it can take several days for the required number of antibodies to be produced.
• Secondary immune response: Imagine what happens if the same antigen that came before comes back into the body. Then, those memory cells remember it. They multiply quickly, become plasma cells, and produce antibodies very quickly. This is also the reason why you recover quickly when you get sick the second time.

So, where in our body are these lymphocytes produced and located?

Lymphocytes are produced in our bone marrow.Then, they mature, meaning they grow well, and enter the bloodstream. Mature lymphocytes can be found in our blood and in all parts of the lymphatic system .

Some lymphocytes go to a place called our thymus gland . Those lymphocytes become T cells. Other lymphocytes go to our lymph nodes and other organs. Those are the ones who become B cells.

What do lymphocytes look like?

Lymphocytes are cells that are slightly larger than red blood cells . However, they are too small to be seen under a microscope. Each lymphocyte has a large nucleus in the middle. This nucleus is dark purple. The jelly-like substance around it, called cytoplasm , is light purple.

What is the normal number of lymphocytes?

The number of lymphocytes in our body can vary from person to person. It depends on things like age, race, gender, altitude, and our lifestyle.

• In an adult, there are usually between 1,000 and 4,800 lymphocytes per microliter of blood.
• For young children, this number is a bit higher. They may have between 3,000 and 9,500 lymphocytes per microliter of blood.

Lymphocytes normally make up between 20% and 40% of the total white blood cells in our body.

What happens if the number of lymphocytes is high?

When the number of lymphocytes in the blood is higher than normal, we call it lymphocytosis . This often happens because of an infection or illness. Our bodies sometimes produce extra lymphocytes to help fight infections.

However, some serious conditions can also cause an increase in the number of lymphocytes. Some of these conditions include:

• Hepatitis
• Syphilis
• Mononucleosis
• Tuberculosis
• HIV and AIDS
• Hypothyroidism
• Infections such as whooping cough , toxoplasmosis, or cytomegalovirus
• Blood cancers such as lymphoma or leukemia

What happens if the number of lymphocytes is low?

When the number of lymphocytes in the blood is lower than normal, we call it lymphocytopenia or lymphopenia . This can happen because of the flu or another minor infection. However, a more serious illness or condition can also cause a decrease in the number of lymphocytes. Here are some of the causes:

• HIV or AIDS
• Tuberculosis or Typhoid fever
• Viral hepatitis
• Blood diseases such as Hodgkin's disease
• Autoimmune diseases such as lupus
• Rare hereditary conditions such as Severe Combined Immunodeficiency (SCID), Ataxia-telangiectasia, DiGeorge syndrome, and Wiskott-Aldrich syndrome
• Treatments such as radiation therapy or chemotherapy

What tests check if my lymphocyte levels are healthy?

There are several blood tests that can determine the number of lymphocytes in your blood. The main ones are:

• Absolute Lymphocyte Count: This is part of a routine Complete Blood Count (CBC) test. It measures the number of lymphocytes in your blood as an absolute number, not as a percentage.
• Flow cytometry: This is a test done in a specialized laboratory. A sample of your blood is dissolved in a liquid and passed through a laser device called a flow cytometer. The laser light causes your blood cells to scatter into patterns. The patterns allow the different types of cells to be clearly seen and counted.

What are the common symptoms of conditions related to lymphocytes?

In most cases, there are no specific symptoms of lymphocytosis (increase in lymphocytes) or lymphocytopenia (decrease in lymphocytes). However, if the number of lymphocytes is increased due to a blood disease or cancer, symptoms related to that disease may appear. Some of these symptoms include:

• Swollen lymph nodes
• Night sweats
• Fever
• Abdominal pain
• Loss of appetite
• Shortness of breath

Finally, the most important thing you need to remember!

Lymphocytes are a very important type of white blood cell in our body. They are the main part of our immune system and protect us from diseases. A simple blood test can tell you how many lymphocytes you have.

It can be a little scary to find out if your lymphocytes are higher or lower than normal. But most of the time, a change in your lymphocyte count can mean that your body is fighting an infection. So don't worry unnecessarily.

If you have any doubts or questions about this, the best thing to do is to see your doctor and talk about it. Your doctor will be able to find the exact cause and do what is necessary to get you back to normal.