Influenza “flu”

What Is Lymphopenia?


Lymphopenia (also called lymphocytopenia) is a disorder in which your blood doesn’t have enough white blood cells called lymphocytes. Lymphocytes play a protective role in your immune system.

There are three types of lymphocytes. All lymphocytes help protect you from infection, but they have different functions.

  • B lymphocytes are made in the bone marrow. These cells make antibodies to help you get better when you are sick (humoral immunity).They also may protect you from future illness.
  • T lymphocytes develop in the thymus gland, an organ in the chest that is part of the lymphatic system. T cells can kill virus-infected cells or cancer cells and signal other cells to help destroy viruses (cellular immunity).T cells also help B cells form antibodies.
  • Natural killer cells, which develop in the bone marrow, thymus, and liver, are immune cells that contain enzymes to kill cancer cells or cells infected with a virus.

Infections can be life-threatening when people have no T nor B cells, as in severe combined immunodeficiency (SCID). In adults, about 20% to 40% of the white blood cells in your body are lymphocytes. These cells help protect your body from infection. If you have low numbers of lymphocytes (lymphopenia), you are at higher risk of infection.

The main risk factor for lymphopenia worldwide is poor nutrition. Infections, diseases, medicines, and other factors also raise your risk for lymphopenia. The most common infection that can lead to lymphopenia is HIV (human immunodeficiency virus), which causes AIDS. Sometimes the cause of lymphopenia is not known.,

Lymphopenia symptoms can range from mild to serious and are correlated to the severity of the lymphopenia as well as its duration. Some people have no symptoms. People who don’t have enough lymphocytes may get infections more often. Treatment for this condition depends on its cause and how serious it is. If an underlying condition is successfully treated, lymphopenia will likely improve

If lymphopenia doesn’t cause health problems, your healthcare provider may not recommend any treatment.

What raises your risk of lymphopenia?

Your risk of lymphopenia is higher if you have one of the diseases, conditions, or factors that can cause a low lymphocyte count. These conditions can be acquired or inherited.

  • “Inherited” means your parents passed the genes for the condition on to you.
  • “Acquired” means you aren’t born with the condition, but you develop it.

Inherited conditions that can lead to lymphopenia

  • Ataxia telangiectasia
  • Chromosome 22q11.2 deletion syndrome (sometimes called DiGeorge syndrome)
  • Common variable immunodeficiency
  • Severe combined immunodeficiency syndrome (SCID)
  • Wiskott-Aldrich syndrome

Acquired conditions that can lead to lymphopenia 

  • Infections such as HIV, viral hepatitis, influenza, SARS CoV-2 (the virus that causes COVID-19), tuberculosis, pneumonia, Sepsis, or malaria
  • autoimmune disorders such as Sjögren’s syndrome, lupus, or rheumatoid arthritis
  • Blood Cancers and other blood diseases, such as Hodgkin’s disease and aplastic anemia
  • Some medical treatments like blood and bone marrow transplant, cancer treatment, steroid therapy, or major surgery
  • Drinking too much alcohol or poor nutrition (having a diet without enough protein or other nutrients)


People who have lymphopenia may have no symptoms at all. If you get colds or pneumonia often or a more unusual infection, your healthcare provider may suspect that you have lymphopenia.

A low lymphocyte count alone may not cause any symptoms. Lymphopenia usually is found during a routine health checkup or when you’re being tested for other diseases or conditions, such as HIV infection.

Lymphopenia can cause one of the signs or symptoms below.

  • Frequent infections, such as colds or pneumonia
  • Unusual infections caused by microbes, fungi, or parasites that rarely cause problems for people who have healthy immune system
  • Long-lasting infections, such as tuberculosis
  • Missing or abnormal tonsils (small organs in the back of the throat)
  • Swollen lymph nodes
  • Skin conditions and abnormalities, such as alopecia (sudden hair loss), eczema (long-term itchy, red skin), pyoderma (bumps on skin that turn into swollen, open sores), pale skin, jaundice (yellowing of the skin and eyes), small bruises, and sores in the mouth
  • Failure to thrive
  • A spleen that is larger than normal that your healthcare provider can feel in an exam


Your provider will do a physical exam to look for signs of infection, such as fever. They may check your stomach for signs of a spleen that is larger than normal and your neck or armpits for signs of lymph nodes that are larger than normal.

Your provider also will look for symptoms of diseases and conditions that can affect your lymphocyte count, such as HIV and blood cancers.

 Your provider may ask:

  • About your risk for HIV infection such as intravenous (IV) drug use, sexual partners, exposure to infectious blood or bodily fluids at work, or blood transfusions
  • Whether you’ve ever had Cancers treatments such as radiation, chemotherapy or immunotherapies
  • Whether you’ve ever been diagnosed with a blood disease or immune disorder, or whether you have a family history of such illnesses
  • About your diet and other lifestyle habits

Diagnostic tests

Your healthcare provider may recommend tests to help diagnose a low lymphocyte count. Some of these tests may need to be repeated.

  • A complete blood count with differential checks the numbers of lymphocytes, as well as red blood cells, platelets, and other types of white blood cells in your blood.
  • Flow cytometry measures the levels of the different types of lymphocytes — T cells, B cells, and natural killer cells. This helps healthcare providers find the underlying cause of lymphopenia.
  • Immunoglobulin level tests check the levels of antibodies called immunoglobulins, made by B lymphocytes. The total levels may be low due to low counts of B lymphocytes, or some groups of B cells, although present, may be dysfunctional and not produce normal amounts or some fractions of antibodies.
  • Other tests can check for different diseases that cause lymphopenia such as HIV, COVID-19 or other viruses, tuberculosis, or other blood or immune conditions. Your provider may also test your bone marrow or your lymph nodes.

What the numbers mean

Healthy levels of lymphocytes are different for adults and children, and may vary more based on your age or overall health.

  • Adults: A normal lymphocyte count usually is between 1,000 and 4,800 lymphocytes per microliter of blood. Your provider may diagnose you with lymphopenia if you have less than 1,500 lymphocytes per microliter of blood for adults.
  • Children: A normal lymphocyte count is variable depending on the child’s age. The percentage and absolute lymphocyte counts are higher in very young children. Your child age 6 and younger may have lymphopenia if they have less than 2000 lymphocytes per microliter of blood.


Treatment for infections

A low lymphocyte count makes it hard for your body to fight infections. You may get infections caused by virus, fungi, parasites, or bacteria. Treatment for an infection will depend on its cause. You also may need treatment after an infection is gone to help prevent repeat infections.

People who have serious, ongoing bacterial infections may get a medicine called immunoglobulin. This medicine helps boost the immune system and fight infections. In some cases, when there is a low level of immunoglobulins, your provider may indicate regular infusion of Immunoglobulins to prevent infections.

Treatment for diseases or conditions that cause lymphopenia

Many diseases and conditions raise your risk of developing lymphopenia. Some examples include lupus or other autoimmune disorders, aplastic anemia, infections such as HIV, and inherited diseases 

such as Wiskott-Aldrich syndrome.

Your treatment will depend on the specific disease or health condition you have. Once you receive medicine or other treatment for the medical condition causing lymphopenia, the levels of lymphocytes in your blood will likely improve.

Potential new treatments

Researchers are actively studying ways to increase lymphocyte production in people who have lymphopenia. For example, some studies are looking into a treatment called blood and marrow stem cell transplants. This procedure may help treat or cure some of the conditions that can cause a low lymphocyte count. Other studies are looking at medicines and other substances that can help the body make more lymphocytes.



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