Lymphocytes are cells that are part of white blood cells, which are responsible for ensuring and securing the immune system of an invading enemy, whether: infections, viruses, fungi, bacteria or parasites. Its function is to carry out immune responses against microorganisms that disrupt the work of the defense system.


These make up 21-42% of all white blood cells that are already in the bloodstream. They are born in the bone marrow and spread throughout the circulatory system and lymphatic tissue. When an antigen becomes present to damage the immune system, a group of lymphocytes gather to battle and completely eliminate external agents.

Antigens are substances that activate the immune response, so that our blood system is alert and gets to know the commitment, always safeguarding the defenses. Lymphocytes are vital cells, they have the ability to know the invading enemy, look for it and adhere to it and then discard it from the immune system, in such a way that our body does not suffer superior reactions. In addition, it has the ability to remember the anti organisms that invaded the system before, which allows the detection and destruction of it later.


Characteristics of lymphocytes
Function Protect the system from external harmful organisms
Type Agranulocytes
Latin Name Lymphocytus
Normal Values 1,320 – 4000 cells/mcL
Quantity of total white globules Between 20 % – 40 %.


What are the types of lymphocytes?

There are two groups of lymphocytes, giants and small ones. Among the giants we have the NK cells, and in the small group the T lymphocytes and B lymphocytes.

This cell is located in the lymphatic system and the bloodstream, has some antigen receptors, so the elimination of them is a job they have the opportunity to do with greater simplicity. There are two giant groups of lymphocytes that move in three directions. These make a group work to try to find the purpose of the cell, to eliminate the antibodies that damage the immune system. The groups are giant and small; they are divided into Natural Killer cells, B lymphocytes and T lymphocytes.


Lymphocytes Large

Natural Killer Cell: These are the most giant lymphocytes, which act most quickly and are part of the agranulocytes. This cell, as its name suggests, (NK) natural killer, has the function of removing or killing infected cells that are damaging the immune system. They destroy them by directly attacking the plasma membranes.

Small Lymphocytes

B-lymphocytes (B-cells): B-lymphocytes detect invasive substances, or antigens. When B cells bind to the immune response, plasma cells develop. Plasma cells fill with antibodies. The indispensable function of this B cell is to produce the antibodies that will help eliminate the invader.

T lymphocytes (T cells): This cell has the function of removing all the antibody that is disrupting the performance of the immune system. In addition, they have the ability to remember the opponents who were already destroyed, so that in a next attack of an antibody that has been eliminated previously, the cell remembers it and has the necessary mechanisms that will help an easy expulsion of them.

Histology of Lymphocytes

Lymphocytes are white cells that develop in lymphoid organs such as the spleen, thymus gland, and bone marrow. Seen from the microscope, they have a basophilic cytoplasm and their nucleus is round and colossal in size. This nucleus is dressed in blue and violet. The cytoplasm released by the lymphocytes is never exact as it is closely linked to the situation of the cytoplasm, may be abundant or little.

The lymphocytes sustain the assaults of antibodies that invade the immune and blood systems. They have the opportunity to modify into plasmocytes in order to produce the primordial glycoproteins. These glycoproteins are the same antibodies that attach to antigens.

Sensitive cells and antigens bind in the damaged region, in addition to the memory advance that the lymphocytes have in group with the accompanying groups (NK, B and T cells), admit that they are organized to have a faster and more effective immune response.

Why carry out a lymphocyte count?

The levels of white blood cells in the blood system detail the way our body and defence system is working. The giant groups of this white cell are: theseinophils, monocytes, neutrophils, leukocytes and lymphocytes. Each one has a task where they assist in sustaining the immune system in line.


                                                            Lymphocytes protect the system from any bacteria or infection.

But, what happens if any of these cells decreases or increases?

En each case wants to express anomalies that are not convenient to health and that are unbalancing the power to ensure and secure the defenses. For that reason, it is remarkable to sustain the levels of lymphocytes in the correct numbers. If we perceive weakness or immunodeficiency disorders, the doctor will ask us to perform a white cell count test, since they are the ones who are faithfully filling in the defense of the immune system and are being attacked.

Why need it?

As we have said before, white blood cells are a group of cells that are filled to control that the immune system is not attacked directly, which allows us to react to allergies, viruses and different infections. A lymphocyte count is recognized through a blood test, in which we can check the proportion of white cells ready to fight against opponents.

In many cases it is the doctors themselves who prescribe the test, this may be because they have suffered viral infections that have caused an increase in antibodies. On numerous occasions, lymphocytes are tested to cover advances in viruses such as HIV or pathologies such as leukaemia, in which the defences are weaker.

What do I need to do before the test?

To carry out the test you don’t need any more preparation. You have to go to a medical clinic and ask for a blood test of the lymphocyte count. Often you will be given the values of all the white blood cells in the blood system.

It is preferable to tell your doctor about the use of any medication, as this may change the results of the test.
Do not eat giant proportions of food, nor do sport before conducting the test.
Talk to your doctor about your entire medical history of pathologies, viruses and allergies.

Steps to carry out the lymphocytes test



It’s a blood test, you just have to go to the medical clinic and ask for it.

  • You will go to a room in the clinic to carry out the test.
  • The doctor will put a rubber band to squeeze the arm and see the vein from which the blood will be drawn.
  • Clean the arm with alcohol, to disinfect.
  • It will introduce the injection, the evil is very slow, it feels like the itch of an ant
    Slowly draw blood.
  • Remove the injection and place the blood in a test tube.
  • Place a small bandage at the injection site


Symptoms of high lymphocytes

High lymphocytes or lymphocytosis is the increase of the cell to more than 4,000 cells per mcL of blood. This increase does not come from a pathology, it is a reaction to infections and allergies. The lymphocytes are forced to intervene in the immune advance, and for this reason the production increases. It is an immune reaction.

This can be triggered by the war of some infections and allergies. For this reason the most recurrent symptoms of this increase are:

  • Fever
  • Fatigue
  • Digestive and respiratory problems
  • Chills and nausea
  • Weight loss
  • Lack of visibility and concentration

The increase in lymphocytes must be regulated quickly, this increase if it continues for an extended time may develop stronger pathologies such as cancer, asthma or some type of diabetes.


What does it mean to have low lymphocytes?

The low level of lymphocytes or lymphocytopenia, there must be a decrease of less than 1,300 cells/mcL of blood. This is due to the fact that the cell became weaker because they have come to guarantee and fight against invaders in the immune system.

The most recurrent elements of this reduction of the cell is malnutrition or viruses such as HIV. This anomaly does not frequent to have symptoms, in extreme cases it has fevers and tiredness, characteristic of the same infection. On several occasions, mammary cell transplants are used to increase lymphocytes.

Types of lymphocytopenia

Acute: It has a more rigorous time of duration due to the fact that the viruses that are battling are very strong.

Chronic: It has a shorter lifespan, the decrease happens when the virus is in the body and is resolved when it is eliminated. This happens frequently with the consumption of some medicines, fasting, infections or chemotherapies.

The number of lymphocytes in the blood of a child is always greater than that of an adult, this originates because they are more prone to different pathologies and they have to act to defend it.


The most frequently asked questions about lymphocytes are as follows:

What does it mean to have high lymphocytes?

Lymphocytes are a remarkable section of white blood cells, which take care to perform stronger and ensure the immune system of some bacteria or infection that can fight it. A prominent level of lymphocytes can manifest itself through different immune disorders or viral infections that the bloodstream is battling.

A prominent level of lymphocytes can manifest through different immune disorders or viral infections that the bloodstream is struggling with. In addition, it can mean pathologies such as leukemia.

Low Lymphocyte Criteria

Leukocytes or white blood cells are the cells that ensure the effectiveness of the immune system. A low lymphocyte count can be a reaction to the presence of different viruses that are attacking the body. It may be due to the temporary presence of several viruses, at various times even cancer.

Suggested Lymphosite Levels

Lymphocytes are the smallest white blood cells in the bloodstream, but with a lot of them, between 20 and 40% in the entire blood system. Suggested cell values are 1,310-4,000 cells/mcL.

 Having lymphosites activated

It is required to admit that if we have lymphocytosis or a prominent level of the cell, it may be due to several occasions whether benign or malignant. This is linked to the severity of the virus and infection, to cover this we must perform a blood study that shows the morphology and size of the lymphocytes.

 What is the function of T lymphocytes?

Also known as T cells, they are formed in the bone marrow from stem cells. Their indispensable work is to guarantee the immune system of some kind of virus and infection that attacks it. They are the evolution of a blood cell that memorizes the viruses that were already discarded, and has the function of totally eliminating the antigens.


Normal Lymphocyte Values

A human being has about 5,000 and 10,500 leukocytes per millimeter. When we are born these values increase and are estimated at an average of 20,000 leukocytes per mm2 of blood. This means that as the years go by, it descends, because the body becomes more resistant and only needs enough leukocytes to live safely.

Normal values in the blood are on average 1500 to 4,100 microliter blood cells. It is the same to say that they occupy around 25% of the toral white blood cell count.

Information related to lymphocytes

What is the importance and development of leukocytes in the immune system?

It should be noted that leukocytes are classified into 5 groups:

Lymphocytes, monoliths, basophils, neutrophils and eosinophils.

These types of white blood cells are essential for the correct action of the human body’s defensive system. White blood cells are produced inside the human bone marrow, after a process they mature in livers, kidneys, nodes and others.


Diseases that cause high and neutrophilic lymphocytes

In the bloodstream are the largest groups of white globules that are neutrophils. The function of these leukocytes is to combat and eliminate harmful oeganisms such as bacteria and viruses. The fall of neutrophils or leukocytes is defined as neutropenia.

We know that in a normal situation the amount of neutrophils is high compared to lymphocytes. In the case of an analysis where neutrophils are lower than lymphocytes, a problem arises, most likely a bacterial infection.


The immunity of the physiological system, the lymphocytes.


Here we see the lymphocytes seen from a microscope.


Lymphocyte Images



More about Lymphocytes

References found in lymphocytes articles

Hughes-Jones, Nevin C.; Hay, Deborah:  Ematology and treatment

Britannica :   Editor of Enciclopedy Britannica

Elsevier Health Sciences :  Elsevier’s integrated review immunology and microbiology




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