Doctors use blood tests to gain valuable insights into your overall health. These tests can reveal your risk for conditions like diabetes or heart disease and assess the health of your kidneys and liver. A lymphocytes blood test is a crucial part of this process, as it measures the level of lymphocytes in your body, providing information about the health and functionality of your immune system.
Discovering you have low lymphocyte levels can be concerning. While low lymphocytes can sometimes be linked to serious conditions like cancer, in many cases, the cause is less severe. Consulting with your doctor to understand your specific levels and determine the appropriate next steps can help alleviate anxiety and provide clarity.
This article will cover the definition of lymphocytes, normal and abnormal ranges, causes and symptoms of low lymphocytes, and what to do if your lymphocytes are low.
A lab technician analyzes blood samples to determine lymphocyte levels.
Understanding Lymphocytes and Their Role
Lymphocytes are a type of white blood cell produced in the bone marrow and found in the blood and lymph tissue. They constitute up to 40 percent of your total blood volume and are essential for a healthy immune system. Lymphocytes defend your body against foreign invaders, such as bacteria and viruses, which can cause infections.
Lymphocytopenia, also known as lymphopenia, occurs when you don’t have enough lymphocytes in your blood. In many instances, lymphocytopenia doesn’t cause noticeable symptoms and is often detected during a routine health checkup or when testing for other conditions.
Lymphocytopenia can result from:
- The body not producing enough lymphocytes.
- Diseases, like cancer, destroying or damaging lymphocytes.
- Lymphocytes becoming trapped in the lymph nodes.
Lymphocytopenia can be either acute or chronic. Acute lymphocytopenia is temporary, with levels decreasing after an infection and returning to normal shortly after. Chronic lymphocytopenia is when low lymphocyte counts persist for months. In cases of chronic lymphocytopenia, doctors typically order further tests to identify the underlying cause.
In adults, a normal lymphocyte count typically ranges between 1,000 and 4,800 lymphocytes per microliter of blood. A diagnosis of lymphopenia may be given if you have fewer than 1,500 lymphocytes per microliter.
Elevated lymphocyte levels (above 4,800) may indicate a different condition called lymphocytosis, often triggered by the body’s response to a temporary infection or inflammatory condition. However, more serious conditions like leukemia and non-Hodgkin lymphoma can also cause lymphocytosis. Other potential causes include stress and reactions to certain medications.
If your lymphocyte levels are abnormally high, your doctor will investigate the cause to determine if treatment is needed. For example, a common cause of high lymphocytes is the Epstein-Barr virus (which causes mononucleosis), often treated with over-the-counter pain relievers and rest.
Lymphocyte levels below 1,000 may also be temporary, suggesting a mild infection or the flu. The primary concern with low lymphocytes is that it can increase your risk of more serious infections because it indicates that your immune system isn’t functioning optimally.
Types of White Blood Cells
There are several types of white blood cells, each with specific functions:
- Granulocytes: These include neutrophils, eosinophils, and basophils.
- Monocytes: These help remove dead or damaged cells.
- Lymphocytes: These have two main subtypes:
- B-cell lymphocytes: Produce antibodies to protect the body from foreign substances like bacteria.
- T-cell lymphocytes: Either help B-cells produce antibodies (helper T-cells) or directly kill foreign substances (killer T-cells).
Changes in the levels of each type of white blood cell can indicate specific conditions or diseases. For example:
An Increase in eosinophils may indicate an allergic reaction or parasitic infection.
An increase in monocytes may be caused by a chronic inflammatory disease, tuberculosis, or a viral infection.
A decrease in monocytes may signal a bloodstream infection, skin infection, or bone marrow disorder.
An increase in neutrophils may be triggered by stress, an infection, gout, trauma, or pregnancy.
A decrease in neutrophils may be caused by certain types of anemia (a lack of red blood cells), a bacterial infection, or the flu.
A decrease in basophils may be triggered by an acute allergic reaction.
Illustration showing the different types of white blood cells, including lymphocytes.
Measuring Lymphocyte Levels
Low lymphocyte levels are usually detected during a routine blood test. A complete blood count (CBC) includes an absolute lymphocyte count, which indicates the total number of lymphocytes in the body. The absolute lymphocyte count can also be measured using a white blood cell (WBC) differential, which calculates the percentage of each type of white blood cell in the body.
Factors such as age, race, and lifestyle can influence the number of lymphocytes in the body, so there is no single “normal” number. Maintaining lymphocyte levels within a healthy range is vital for a properly functioning immune system.
Causes of Low Lymphocytes
Most cases of lymphocytopenia are acquired, often through diseases such as viral hepatitis, human immunodeficiency virus (HIV), lupus, or Hodgkin lymphoma, or through cancer treatments like chemotherapy or immunotherapy. Rarely, babies are born with lymphocytopenia due to inherited conditions like Wiskott-Aldrich syndrome, a rare immune system disorder that reduces the body’s ability to produce lymphocytes, or DiGeorge syndrome, a condition causing heart defects, low calcium levels, and impaired immune function.
Other factors that can contribute to low lymphocytes include:
- Malnutrition
- Severe physical stress
- Severe illness and trauma
- Steroid use
Even intense exercise, such as high-intensity interval training, or alcohol consumption can affect lymphocyte counts, according to Revathi Suppiah, MD, Medical Oncologist at City of Hope Phoenix. Chronic low levels are what typically cause concern.
Symptoms of Lymphocytopenia
Often, individuals with lymphocytopenia don’t experience any noticeable symptoms. When symptoms do occur, they may include:
- Frequent infections, such as pneumonia
- Unusual infections that typically don’t affect people with healthy immune systems
- Infections that persist
- Swollen lymph nodes (especially in the neck or groin)
- An enlarged spleen
- Skin conditions like eczema and alopecia (hair loss)
- Joint pain and swelling
- Signs of a viral infection, such as fever, cough, or runny nose
What to Do If Your Lymphocytes Are Low
If your doctor suspects lymphocytopenia, they will attempt to determine the underlying cause by reviewing your medical history, performing a physical exam to check for visible symptoms, and, in some cases, ordering a flow cytometry test, which measures the levels of different types of lymphocytes, including T-cells and B-cells.
For mild cases of lymphocytopenia without a clear cause, your doctor may not recommend treatment and will instead monitor the condition to see if it resolves on its own. If your doctor identifies a specific cause, such as cancer or another serious condition, they may recommend treatment targeting that cause.
In some cases, especially when the condition is chronic, your doctor may refer you to a hematologist. If the condition is caused by chronic conditions like lupus or another autoimmune disease, it may require long-term management with a combination of medications.
The goal for patients with low lymphocytes is to increase counts to a healthy range by addressing the underlying cause. Protecting against infection is also crucial.
“Lymphocytes play an important role in your immune system and help protect you from developing infections,” says Dr. Suppiah. “Therefore, a low lymphocyte count may predispose you to certain infections.”
Therefore, take steps to reduce your risk by:
- Getting recommended seasonal vaccines
- Avoiding people with contagious viruses or other illnesses
- Washing hands thoroughly and regularly
- Practicing good oral hygiene
Whether you should be concerned about low lymphocyte levels depends on the cause, the severity of the count, and whether you are symptomatic (experiencing recurrent infections), according to Dr. Suppiah. Always discuss your concerns with your doctor.
