Lymphocytes – Normal Range, High, Low

What are lymphocytes ?

Lymphocytes refer to a kind of white blood cells that can be found in the blood of a human body. All of us are aware of the importance of white blood cells in the body and the role that they play in protecting the body and fighting against invasions of the body by bacteria and other organisms. Thus they are responsible for preventing the onset of infections in the body which may lead to many kinds of health complications. The lymphocytes thus play a vital role in helping the body fight against viral infections as well as the growth of tumors.

There are three major kinds of lymphocytes that can be found in the human body. They include the T cell lymphocytes, NK cell lymphocytes and the B cell lymphocytes. The “NK” in NK cell lymphocytes refer to natural killer. Each of these lymphocytes has a particular function to perform and in combination, make the immune system of the body increasingly strong and impenetrable.

A number of studies have indicated that B cell and T cell lymphocytes are also instrumental in preventing and controlling the development of dangerous cancerous cells. The lymphocytes form about 15 percent to 40 percent of the total number of white blood cells present in the body. A decrease or increase in the normal levels of lymphocytes is considered as abnormal and usually an indication of the presence of some infections or health conditions.

Normal lymphocyte count in blood

• The normal levels of lymphocytes present in the blood usually range between 1200 and 3200 lymphocytes per milliliter of blood. However, it may be noted that different laboratories may follow different standards of valuing the normal levels of lymphocytes. Hence, it is important to consult a doctor for interpretation of the lab results of a blood test as also for understanding the status of lymphocyte levels.

High lymphocyte count 

• Lymphocytes are vital to the defense of the human body against invasion by different types of foreign organisms. Due to this characteristic of lymphocytes, they often reject the transplant of even a healthy tissue because they recognize the transplanted tissue to be an alien object. They are manufactured in the bone marrow. They are able to live for many weeks, or several years or even the full life time of an individual.
• As discussed earlier, when lymphocytes form more than forty percent of the total number of white blood cells in the body, then it indicates the presence of high lymphocytes count. This condition is referred to as Lymphocytosis. However, the presence of a decreased percentage of lymphocytes in the human blood indicates low lymphocytes count, resulting in a condition called Lymphocytopenia.

A high lymphocytes count may be caused due to the presence of a number of underlying conditions which are as follows:

• Chickenpox
• Whooping cough
• Flu
• Rubella which is a viral infection
• Mumps
• Tuberculosis
• Brucellosis which is an infection contracted from animals
• Medication side effects
• Herpes simplex, which is a virus infection that causes symptoms similar to flu and cold
• CLL or Chronic lymphocytic leukemia
• ALL or Acute lymphocytic leukemia
• Mononucleosis
• Hepatitis
• Toxoplasmosis which is an infection that primarily occurs in birds, animals and reptiles, but can also affect humans.
• Cytomegalovirus which is a viral infection affecting the stomach and/or the eyes
• Crohn’s disease
• Blood transfusion
• Ulcerative colitis, which is an inflammatory bowel disorder
• Multiple myeloma which is plasma cell cancer
• Vasculitis which is condition caused due to inflammation of blood cells
• Autoimmune disorders
• Other bacterial, viral, or similar infections

Low lymphocyte count in blood

• A low lymphocytes count is also as dangerous a condition as a high lymphocytes count. When the percentage of lymphocytes that form the total number of white blood cells in the human body is lower than fifteen percent, then it signifies low levels of lymphocytes in the body.

Just like high lymphocytes count, low levels of lymphocytes may also point to the possible presence of an underlying condition. Some of these health conditions include the following:

• Aplastic anemia
• Steroids use side effects
• HIV / AIDS
• Tumors
• Multiple sclerosis
• An overactive adrenal cortex
• Guiallain-Barre syndrome which refers to weakness in legs and arms, which generally results from nerve damage
• Myasthenia gravis which refers to muscle weakness

Treatment of abnormal lymphocytes count

It may be noted that abnormal levels of lymphocytes do not result in any specific symptoms. It is only the underlying condition that causes all the symptoms, which may then prompt a patient to visit a doctor for diagnosis and treatment.

After a CBC blood test results are out and abnormal levels of lymphocytes are detected, the doctor will recommend a number of other tests to identify the underlying condition causing the various symptoms, including abnormal lymphocytes count. These tests are necessary because the lymphocytes count alone is not sufficient in diagnosing the pre-existing medical condition.

Once the doctor has correctly determined the medical disorder causing abnormal lymphocytes levels, he/she will recommend the proper treatment. The successful treatment of the underlying condition will then result in the lymphocytes count returning to normal levels.