High Lymphocytes: Levels, Diagnosis, Symptoms, Causes, Treatment and Tips

It is a common condition after illness, known as lymphocytosis.

Lymphocytosis can be a serious problem if it persists.

Lymphocytes are a type of white blood cell found in our body and play a very important role in our immune system.

These help you fight disease and keep you protected and healthy. If you have recently been through an infection or illness, then it is common for your body to have a high lymphocyte count, also known as lymphocytosis .

More commonly, it means that you have a viral infection, but it can sometimes also mean an autoimmune disorder or a certain form of cancer or leukemia.

How much count is considered high?

If you are an adult and have more than 3,000 lymphocytes (<40%) in a microliter of blood, then a high lymphocyte count, also known as lymphocytosis, is already considered.

You should know that a low lymphocyte count can also have consequences, so we recommend that you check what is the normal range of lymphocyte count.

You should know that there are two types of lymphocytosis:

  • Monoclonal Lymphocytosis : Also known as MBL, the blood test will show a low level of CLL (> 5000 per microliter of blood). Although it is not a genetic disorder, people over the age of 40 may have a greater predisposition if it is a family and it increases with age.
  • Polyclonal Lymphocytosis : Also known as PPBL (Persistent Polyclonal Lymphocytosis), it will show a stable MBL, which is how it can be differentiated from the latter. PPBL also does not need to show a lymphocyte count as high as MBL. Caucasian, young, smoking women have the highest risk factor.

How do you know if you have an elevated lymphocyte count?

Usually, the person who has a high lymphocyte count, a condition that is medically known as lymphocytosis, does not show physical symptoms.

This means that you will never know unless you have a blood test for another reason, and your doctor identifies it alongside. There is also no treatment for the condition, and it can only be managed by managing the underlying cause.

Once the tests are done, if you have noticed that you have a high lymphocyte count, it is very important that you bring the results to your GP so that more tests can be done to determine the cause.

What are the symptoms of high lymphocytes?

Generally, the increase in the number of lymphocytes does not cause symptoms.

However, in people with lymphoma and certain leukemias, elevated lymphocyte counts can cause:

  • Fever.
  • Night sweats
  • Weightloss.

Also, symptoms may be the result of infection or another disease that has caused the number of lymphocytes to increase, rather than the increase in lymphocytes per se.

When an infection is suspected, doctors can do blood tests.

When doctors discover increased numbers of lymphocytes, a sample of blood is examined under a microscope to determine if the lymphocytes in the blood appear activated (as occurs in response to viral infections) or if they appear immature or abnormal (as occurs in certain leukemias or lymphomas).

Blood tests can also identify the specific type of lymphocyte (T cells, B cells, natural killer cells) that is increased to help determine the underlying problem.

What Causes a High Lymphocyte Count?

If you have been diagnosed with an elevated lymphocyte count, you should know that there are two types of lymphocytes or a high lymphocyte count: monoclonal and polyclonal, both of which have different causes.

Causes of monoclonal or primary lymphocytosis

Monoclonal lymphocytosis is a proliferative disease in which the number of lymphocytes increases as a result of a lymphocyte-related disorder.

It is caused by:

  • Lymphoid tumors.
  • Prolymphocytic leukemia (PLL).
  • Hair cell leukemia (HCL).
  • Lymphomas with leukemic expression.
  • Large granular lymphocytic leukemia.
  • Acute lymphoblastic leukemia (ALL) and chronic lymphocytic leukemia (CLL).

Leukemia is a type of blood cancer in which the bone marrow is replaced by the early forms of white blood cells.

ALL is a type of leukemia in which large numbers of underdeveloped and immature white blood cells, known as blasts, are produced in the bone marrow.

Lymphoblasts, which are immature lymphocytes, are a type of blast present in ALL cases. CLL is a type of leukemia characterized by the presence of an excessive number of mature lymphocytes.

It is the most common type of leukemia in adults, particularly in the elderly, and predominantly affects men more than women. The most common signs and symptoms are:

  • Swelling of the lymph nodes.
  • Fatigue.
  • Weightloss.

Causes of polyclonal or reactive lymphocytosis

Polyclonal lymphocytosis occurs before an inflammatory or infectious process.

It can be caused by:

Viral infections:

  • Mononucleosis Syndromes Caused by Cytomegalovirus.
  • Hepatitis.
  • Rubella.
  • Herpes simplex virus, better known as cold sores and chickenpox.
  • Adenovirus.
  • Influenza.
  • Mumps.

Bacterial infections:

  • Toxoplasmosis.
  • Tuberculosis.
  • Brucellosis.

Poisoning by certain substances:

  • Lead.
  • Benzene and others.
  • Metabolic disorders, such as diabetic or uremic acidosis.
  • Certain vitamin B12 treatments.

 Acute causes:

  • Septic Shock .
  • Acute heart failure.
  • Surgery.
  • Drug addiction.
  • Transfusions

Chronic causes:

  • Smoke.
  • Spleen removal (splenectomy).
  • Autoimmune diseases and chronic inflammation, such as Crohn’s disease, ulcerative colitis, and vasculitis.

What is the treatment for high lymphocytes?

Treatment for a high lymphocyte count will be applied depending on the underlying cause or condition.

For example, because chronic lymphocytic leukemia is often slow-growing, not all of them need to be treated right away. When treatment is needed, the main treatments used are:

  • Chemotherapy for chronic lymphocytic leukemia.
  • Monoclonal antibodies for chronic lymphocytic leukemia.

Other treatments

Less commonly, the following treatments may be used to treat CLL:

  • Leukapheresis for chronic lymphocytic leukemia.
  • Surgery for chronic lymphocytic leukemia.
  • Radiation therapy for chronic lymphocytic leukemia.

When to contact a doctor

Elevated lymphocyte count is mostly found when you are already experiencing a condition, and your doctor has ordered a test to diagnose it.

This means that in most cases, lymphocytosis is discovered by chance and is usually an unexpected detection. When you have the tests in hand, talk to your doctor about the possible causes and consequences, and discuss the best treatment procedure for your condition.


Talk to your doctor about your high lymphocyte count to find out if it is relevant enough or not.