<p>Lymphocytopenia (LIM-fo-si-to-PE-ne-ah) is a disorder in which your blood doesn’t have enough white blood cells called lymphocytes (LIM-fo-sites).</p><p>These cells are made in the bone marrow along with other kinds of blood cells. Lymphocytes help protect your body from infection. Low numbers of lymphocytes can raise your risk of infection.</p><p>Lymphocytopenia also is called lymphopenia.</p><h2>Overview</h2><p>About 20 to 40 percent of all white blood cells are lymphocytes. A normal lymphocyte count for adults usually is between 1,000 and 4,800 lymphocytes per microliter of blood. For children, a normal lymphocyte count usually is between 3,000 and 9,500 lymphocytes per microliter of blood.</p><p>The term "lymphocytopenia" refers to a count of less than 1,000 lymphocytes per microliter of blood in adults, or less than 3,000 lymphocytes per microliter of blood in children.</p><p>The three types of lymphocytes are B lymphocytes, T lymphocytes, and natural killer cells. All of these cells help protect the body from infection. Most people who have lymphocytopenia have low numbers of T lymphocytes. Sometimes they also have low numbers of the other types of lymphocytes.</p><p>Certain factors can cause a low lymphocyte count, such as:</p><ul><li>The body doesn't make enough lymphocytes.</li><li>The body makes enough lymphocytes, but they’re destroyed.</li><li>The lymphocytes get trapped in the spleen or lymph nodes. Lymphocytes normally pass through these organs into the blood.</li><li>A combination of the above factors.</li></ul><p>Many diseases, conditions, and factors can cause the above problems that lead to lymphocytopenia. These causes can be acquired or inherited.</p><p>"Acquired" means you aren't born with the condition, but you develop it. One of the most common acquired causes of lymphocytopenia is AIDS.</p><p>"Inherited" means your parents passed the gene for the condition on to you. Inherited causes include DiGeorge anomaly, Wiskott-Aldrich syndrome, severe combined immunodeficiency syndrome, and ataxia-telangiectasia. These inherited conditions are rare.</p><h2>Outlook</h2><p>Lymphocytopenia can range from mild to severe. The condition alone may not cause any signs, symptoms, or serious problems.</p><p>How long lymphocytopenia lasts depends on its cause. The treatment for this condition depends on its cause and severity. Mild lymphocytopenia may not require treatment. If an underlying condition is successfully treated, lymphocytopenia will likely improve.</p><p>If lymphocytopenia causes serious infections, you may need medicines or other treatments.</p>
In general, lymphocytopenia (a low lymphocyte count) occurs because:
- The body doesn't make enough lymphocytes.
- The body makes enough lymphocytes, but they’re destroyed.
- The lymphocytes get stuck in the spleen or lymph nodes.
A combination of these factors also may cause a low lymphocyte count.
Many diseases, conditions, and factors can lead to a low lymphocyte count. These conditions can be acquired or inherited. "Acquired" means you aren't born with the condition, but you develop it. "Inherited" means your parents passed the gene for the condition on to you.
Exactly how each disease, condition, or factor affects your lymphocyte count isn't known. Some people have low lymphocyte counts with no underlying cause.
Many acquired diseases, conditions, and factors can cause lymphocytopenia. Examples include:
- Infectious diseases, such as AIDS, viral hepatitis, tuberculosis, and typhoid fever.
- Autoimmune disorders, such as lupus. (Autoimmune disorders occur if the body’s immune system mistakenly attacks the body’s cells and tissues.)
- Steroid therapy.
- Blood cancer and other blood diseases, such as Hodgkin's disease and aplastic anemia.
- Radiation and chemotherapy (treatments for cancer).
Certain inherited diseases and conditions can lead to lymphocytopenia. Examples include DiGeorge anomaly, Wiskott-Aldrich syndrome, severe combined immunodeficiency syndrome, and ataxia-telangiectasia. These inherited conditions are rare.
People at highest risk for lymphocytopenia have one of the diseases, conditions, or factors that can cause a low lymphocyte count. This includes people who have:
- AIDS or other infectious diseases
- Autoimmune disorders
- Blood cancers or other blood diseases
- Certain inherited diseases or conditions
People who have had steroid therapy or radiation or chemotherapy (treatments for cancer) also are at increased risk. For more information, go to "What Causes Lymphocytopenia?"
A low lymphocyte count alone may not cause any signs or symptoms. The condition usually is found when a person is tested for other diseases or conditions, such as AIDS.
If you have unusual infections, repeat infections, and/or infections that won't go away, your doctor may suspect that you have lymphocytopenia. Fever is the most common symptom of infection.
Your doctor will diagnose lymphocytopenia based on your medical history, a physical exam, and test results.
A low lymphocyte count alone may not cause any signs or symptoms. Thus, the condition often is diagnosed during testing for other diseases or conditions.
Your primary care doctor may notice that you have unusual infections, repeat infections, and/or infections that won't go away. These infections may be signs of lymphocytopenia. Your primary care doctor may refer you to an infectious disease specialist to find out what's causing the infections.
You also may see a hematologist (blood disease specialist) or an immunologist (immune disorders specialist). Blood diseases and immune disorders can cause lymphocytopenia.
To assess your risk for a low lymphocyte count, your doctor may ask:
- About your risk for AIDS, including questions about blood transfusions, sexual partners, intravenous (IV) drug use, and exposure to infectious blood or bodily fluids at work
- Whether you've ever had radiation or chemotherapy (treatments for cancer)
- Whether you've ever been diagnosed with a blood disease or immune disorder, or whether you have a family history of such illnesses
Your doctor will do a physical exam to look for signs of infection, such as fever. He or she may check your abdomen for signs of an enlarged spleen and your neck for signs of enlarged lymph nodes.
Your doctor also will look for signs and symptoms of diseases and conditions that can affect your lymphocyte count, such as AIDS and blood cancers.
Your doctor may recommend one or more of the following tests to help diagnose a low lymphocyte count.
Complete Blood Count With Differential
A complete blood count (CBC) measures many parts of your blood. The test checks the number of red blood cells, white blood cells, and platelets in your blood. The CBC will show whether you have a low number of white blood cells.
Lymphocytes account for 20 to 40 percent of all white blood cells. Although a CBC will show an overall low white blood cell count, it won't show whether the number of lymphocytes is low.
You may need a more detailed test, called a CBC with differential, to find out whether you have a low lymphocyte count. This test shows whether you have low levels of certain types of white blood cells, such as lymphocytes. The test results can help your doctor diagnose lymphocytopenia.
Flow cytometry (si-TOM-eh-tree) looks at many types of blood cells. It's even more detailed than a CBC with differential. Flow cytometry can measure the levels of the different types of lymphocytes—T cells, B cells, and natural killer cells.
The test can help diagnose the underlying cause of lymphocytopenia. Some underlying conditions cause low levels of T cells. Others may cause low levels of B cells or natural killer cells.
Tests for Underlying Conditions
Many diseases and conditions can cause lymphocytopenia. Your doctor will want to find the cause of the disorder. You may be tested for HIV/AIDS, tuberculosis, blood diseases, and immune disorders.
Lymph nodes are part of the immune system. They're found in many places in your body. During a physical exam, your doctor may find that certain lymph nodes are swollen. In lymphocytopenia, the lymph nodes may hold on to too many lymphocytes instead of releasing them into the bloodstream.
To test a lymph node, you may need to have it removed. Removing a lymph node involves minor surgery.
If you have mild lymphocytopenia with no underlying cause, you may not need treatment. The disorder may improve on its own.
If you have unusual infections, repeat infections, and/or infections that won't go away due to lymphocytopenia, you'll need treatment for the infections.
If you have a disease or condition that's causing lymphocytopenia, your doctor will prescribe treatment for that illness. Treating the underlying problem will help treat the lymphocytopenia.
Treatment for Infections
A low lymphocyte count makes it hard for your body to fight infections. You may get infections caused by viruses, 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.
Children who have serious, ongoing bacterial infections may get a medicine called immune globulin. This medicine helps boost the immune system and fight infections.
Treatment for Underlying Diseases or Conditions
Many diseases and conditions can cause lymphocytopenia. Examples include infectious diseases, such as AIDS; blood diseases, such as aplastic anemia; and inherited diseases, such as Wiskott-Aldrich syndrome.
Your treatment will depend on your underlying disease or condition.
Researchers are looking at ways to increase lymphocyte production in people who have lymphocytopenia with serious underlying conditions.
For example, some studies are looking into 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.
You can't prevent lymphocytopenia that's caused by an inherited condition. However, you can take steps to control lymphocytopenia. Follow your treatment plan and take all medicines as your doctor advises.
Early diagnosis also can help control lymphocytopenia. In the United States, newborns are routinely screened for an immune condition that can lead to lymphocytopenia. This allows doctors to diagnose the disorder before serious problems develop.
You may be able to lower your risk for acquired conditions that cause lymphocytopenia. For more information about acquired causes of the disorder, go to "What Causes Lymphocytopenia?"
If you have mild lymphocytopenia with no underlying cause, you may not need treatment. The disorder may improve on its own.
If an underlying condition is causing your lymphocytopenia, you'll need treatment for that condition. You'll also need treatment for infections if your body is unable to fight them because of lymphocytopenia.
Treating and Preventing Infections
The main risk of lymphocytopenia is getting unusual infections, repeat infections, and/or infections that won't go away. If you have the disorder, you may get treatments to prevent infections or to treat infections you already have.
You also can take other steps to prevent infections. For example:
- Stay away from people who are sick, and avoid large crowds of people.
- Avoid foods that can expose you to bacteria, such as uncooked foods.
- Wash your hands often.
- Brush and floss your teeth and get regular dental care to reduce the risk of infection in your mouth and throat.
- Ask your doctor whether you should get a yearly flu shot and the pneumonia vaccine.
Know the signs of an infection, such as a fever. Call your doctor right away if you think you have an infection.
Treating an Underlying Disease or Condition
If you have a disease or condition that’s causing lymphocytopenia, you’ll need treatment for that condition.
You'll likely have regular tests to show how the treatment is working. For example, you may have blood tests to check the number of lymphocytes in your blood.
If the treatments for the underlying condition are working, the number of lymphocytes in your blood may go up.
Talk with your doctor about what types and amounts of physical activity are safe for you. You may want to avoid activities that could result in injuries or increase your risk of infections.
The National Heart, Lung, and Blood Institute (NHLBI) is strongly committed to supporting research aimed at preventing and treating heart, lung, and blood diseases and conditions and sleep disorders.
NHLBI-supported research has led to many advances in medical knowledge and care. Often, these advances depend on the willingness of volunteers to take part in clinical trials.
Clinical trials test new ways to prevent, diagnose, or treat various diseases and conditions. For example, new treatments for a disease or condition (such as medicines, medical devices, surgeries, or procedures) are tested in volunteers who have the illness. Testing shows whether a treatment is safe and effective in humans before it is made available for widespread use.
By taking part in a clinical trial, you can gain access to new treatments before they’re widely available. You also will have the support of a team of health care providers, who will likely monitor your health closely. Even if you don’t directly benefit from the results of a clinical trial, the information gathered can help others and add to scientific knowledge.
If you volunteer for a clinical trial, the research will be explained to you in detail. You’ll learn about treatments and tests you may receive, and the benefits and risks they may pose. You’ll also be given a chance to ask questions about the research. This process is called informed consent.
If you agree to take part in the trial, you’ll be asked to sign an informed consent form. This form is not a contract. You have the right to withdraw from a study at any time, for any reason. Also, you have the right to learn about new risks or findings that emerge during the trial.
For more information about clinical trials related to lymphocytopenia, talk with your doctor. You also can visit the following Web sites to learn more about clinical research and to search for clinical trials:
For more information about clinical trials for children, visit the NHLBI’s Children and Clinical Studies Web page.