Lymphocytes are a specific group of white blood cells (leukocytes) that play an essential role in the human immune system. They are responsible for defending the body against foreign microorganisms such as viruses, bacteria or fungi, as well as against damaged or mutated cells that can develop into cancer.

According to function, lymphocytes are divided into three main categories:

1. T-lymphocytes (T cells): These cells play a central role in the adaptive part of the immune response. They help regulate the activity of other immune cells and are directly involved in the destruction of infected cells or cancer cells. T-lymphocytes are divided into several subpopulations, including helper T-lymphocytes (CD4+), cytotoxic T-lymphocytes (CD8+), and regulatory T-lymphocytes.

2. B-lymphocytes (B cells): B cells are responsible for producing antibodies. Antibodies are special protein molecules that specifically recognize foreign bodies, such as parts of viruses or bacteria, and help eliminate them from the body.

3. NK cells (natural killer cells): These cells can recognize and destroy damaged or infected cells without prior specific recognition. NK cells are an important first-line defense against some viruses and cancer cells.

Because of their important function in the immune system, the number and function of lymphocytes are often used in laboratory tests to detect certain diseases or to monitor the immune response during treatment.


What causes an increase in lymphocytes?

An increase in lymphocytes in the blood, medically called lymphocytosis, is a phenomenon in which the number of lymphocytes in the blood exceeds normal values. It can be a temporary condition or long-term, depending on the cause. There are many different factors that can cause an increase in lymphocytes:

  • Infections: Many viral infections, such as chickenpox, measles, rubella, or Epstein-Barr virus (EBV, which causes infectious mononucleosis), can cause transient lymphocytosis. Some bacterial infections, such as tuberculosis or brucellosis, can also increase the number of lymphocytes.
  • Blood cancer: Lymphomas, leukemias, and other malignant blood diseases can cause an increase in lymphocytes because these diseases affect the production of white blood cells in the bone marrow.
  • Autoimmune diseases: When the immune system mistakenly attacks itself, it can cause an increase in lymphocytes. For example, rheumatoid arthritis and Shiele's syndrome can cause an increase in lymphocytes.
  • Chronic infections: Some infections, such as HIV or HCV, can cause a long-term increase in lymphocytes.
  • Medications: Some medications, such as phenytoin (used to treat epilepsy) or corticosteroids, can cause lymphocytosis as a side effect.
  • Endocrine diseases: Some hormonal disorders, such as hyperthyroidism, can cause an increase in lymphocytes.
  • Stress and trauma: Acute stress or trauma can temporarily increase the number of lymphocytes in the blood.

Regardless of the specific cause, an increase in lymphocytes indicates that the body is reacting to some kind of threat or change. Therefore, it is important to carry out detailed investigations to determine the exact cause and, if necessary, start treatment.

Symptoms of an increase in lymphocytes

An increase in lymphocytes in the blood (lymphocytosis) can often be asymptomatic, i.e. occurs without any obvious symptoms. Often this phenomenon is detected by chance during routine blood tests for other reasons. However, depending on the cause of lymphocytosis, other symptoms may occur.

One of the more obvious symptoms of an increase in lymphocytes is swollen, painful or painless lymph nodes in the neck, armpits, upper thigh, or other areas of the body.

When an increase in lymphocytes is associated with an infection or blood disease, fever and night sweats may occur.

Enlarged lymph nodes in the abdominal cavity can cause abdominal pain or discomfort.

An increase in lymphocytes can cause general weakness and lack of energy as the body fights infection or disease.

Depending on the cause, symptoms of infection may occur: These may include a cough, runny nose, pain when drinking, a skin rash, or other symptoms.

In some cases, weight loss, pale skin, easy bruising or bleeding may occur.

Some patients may experience shortness of breath or difficulty breathing if the lymph nodes in the chest cavity are enlarged.

While some symptoms may be related to a temporary condition, such as a viral infection, others may indicate a more serious illness. If you experience one or more of the above symptoms, it is important to see your doctor immediately for further examinations and consultations.


Prevention of lymphocyte increase

Prevention of lymphocyte elevation depends on specific risk factors and potential triggers. Although it is not always possible to prevent this condition, there are some recommendations that can help reduce the risk:

1. Boosting immunity: A varied, balanced diet plan, regular physical activity and adequate rest can strengthen the immune system, reducing the risk of infectious diseases that can cause an increase in lymphocytes.

2. Personal hygiene: Regular hand washing, especially before eating and after using the toilet, can reduce the risk of infections that can cause an increase in lymphocytes.

3.Vaccination: Vaccinate yourself against some diseases that can cause an increase in lymphocytes, such as influenza, hepatitis B or swine flu.

4. Avoiding risk factors: If you know that you have a tendency to autoimmune diseases or blood disorders, monitor your health, follow your doctor's recommendations and do the necessary tests regularly.

5. Avoid tobacco and alcohol: Tobacco use and excessive alcohol consumption can weaken the immune system and increase the risk of certain diseases that can cause an increase in lymphocytes.

6. Avoid chemicals: If you work with toxic substances or live in an environment with high levels of pollutants, try to minimize your exposure to these substances. This may include safety measures at work or the use of air filters at home.

7. Psychological health: Stress can affect the immune system, so stress-reducing techniques such as meditation, relaxation or incorporating exercise into your daily routine can be helpful.


While it's not always possible to completely prevent lymphocyte enlargement, these preventative measures can help reduce the risk and keep your body functioning optimally. If you think you have symptoms of an increase in lymphocytes, see your doctor as soon as possible.


Lymphocytes are an important part of the immune system responsible for protecting the body against infections and other pathogens. An increase in lymphocytes, medically known as lymphocytosis, can indicate a variety of health conditions, from simple viral infections to more serious disorders such as lymphoma or leukemia.

There are various reasons why an increase in lymphocytes can occur. It can be a reaction to an infection, blood disorders, autoimmune diseases, or other medical conditions. Typical symptoms can vary depending on the cause and may include fatigue, fever, enlarged lymph nodes, and more. It is important to determine the exact cause so that the appropriate treatment can be applied.

Taken together, an increase in lymphocytes is an important medical signal that should be taken seriously. Early diagnosis and appropriate treatment are vital to prevent more serious consequences and ensure the best health status for the patient.

Sources of information:

1. National Library of Medicine. (2020). Limfocitai. MedlinePlus.

2. Mayo Clinic. (2019). Virusinės infekcijos.

3. American College of Rheumatology. (2018). Autoimuninės ligos.

4. American Cancer Society. (2020). Leukemija ir limfoma.

5. World Health Organization. (2017). Toksinių medžiagų poveikis.

6. Cleveland Clinic. (2021). Limfocitų padidėjimo simptomai.

7. Johns Hopkins Medicine. (2019). Limfocitų padidėjimo diagnostika.

8. National Institutes of Health. (2020). Limfocitų padidėjimo gydymas.


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