Low Lymphocytes

Lymphocytes are a type of white blood cells present in a vertebrate's immune system, and responsible for protecting the body against damage caused by bacterial and viral infections. There are three main types of lymphocytes; T cells, B cells, and natural killer (NK) cells. Together, these cells build the body's immunity by inhibiting growth of malignant cells, and producing antibodies. Studies indicate that T cells and B cells play a vital role in controlling the growth of cancerous cells. Lymphocytes are produced in the bone marrow along with other kinds of blood cells. A healthy count is integral to the body's defense mechanism. However, there are times when there is a fall in the normal level. In most cases, approximately 15% to 40% of white blood cells are lymphocytes, i.e. the normal range of lymphocyte count is 1000 - 4800/µL. The normal range may differ depending on the machine used to perform the blood test.


A low lymphocyte count indicates that the body's resistance to fight infection is substantially reduced, and one may become more susceptible to certain types of infection, namely cancer and tumor. As lymphocytes make up fifteen to forty percent of the total white blood cells that circulate in the bloodstream, a low count can lead to damage to various organs of the body.

Possible Causes
There are many causes of a low lymphocyte level. But whatever be the reason, it must be treated because if left untreated, a low lymphocyte count will make an individual vulnerable to many infections. As lymphocytes are made in the bone marrow, any deficiency in their functioning can cause the lymphocyte levels to drop. If an individual is suffering from aplastic anemia, in which the bone marrow does not produce sufficient new cells to replenish the blood cells, it can cause a drop in the count.

Infections such as viral or bacterial too can decrease lymphocyte levels, but in most cases the level rises, once the body is free from the infection. However, recurrent infections or immune deficiency syndromes like HIV, AIDS, hepatitis, tuberculosis, typhoid fever, etc., can also lead to low lymphocytes. Inheritable disorders that inhibit the growth of new cells also result in a decrease in lymphocytes. Neurological as well as autoimmune diseases too can decrease lymphocytes in the body.

Drugs and therapy too can cause a drop in the lymphocyte levels. Drugs like steroids, or very strong antibiotics taken as an action course for some infection, or therapy to treat cancer such as radiation or chemotherapy also cause lymphocyte counts to drop, but temporarily. Sometimes lymphocyte cells made by the body get destroyed due to abnormal conditions, mostly autoimmune disorders. Another cause is when lymphocytes get trapped in the spleen or lymph nodes, resulting in a drop in the count.

Signs and Symptoms
When a person has low number of lymphocytes in his blood, he may not show any symptoms pertaining to it. It is when the person is diagnosed for diseases that are a result of low lymphocyte count, that this condition is detected. A person suffering from repeated infections or fever for a long period of time is suspected to have poor immunity due to low lymphocytes.

Tests and Diagnosis
Diagnosis involves detailed assessment of medical history of the person, like risk for developing AIDS, any previous sessions of radiation and chemotherapy, family history of diseases with lymphocytopenia, etc. The doctor carries out a physical examination of the person looking out for signs like enlarged lymph nodes and spleen. He also checks the abdomen and looks for the presence of any kind of infection or fever. After the checkup, the person is asked to go through certain tests like complete blood count with differential, flow cytometry, and other tests for suspected underlying diseases.

Treatment Provided
If drop in the level of lymphocytes is mild and there is no underlying disease involved, doctors do not prescribe any treatment, as it gets back to normal on its own. But if the condition is a result of a disease or illness, then treatment provided is targeted towards the actual cause of lymphocytopenia. Any kind of infection or fever accompanying the disease is also taken care of.

Diagnosis of this condition at an early stage helps in controlling it in a better way. Following the instructions of doctor properly and taking medications as per the treatment plan helps in speedy recovery.