Lymphocytes are white blood cells that play a role in fighting disease. They are present in the lymphoid tissue and the blood. The spleen, bone marrow, and lymph nodes produce lymphocytes.
Chronic lymphocytic leukemia is a form of cancer that starts in the white blood cells that become lymphocytes.
This article takes a look at how chronic lymphocytic leukemia affects the levels of these cells and what that might mean for a person’s outlook.
Not all individuals with chronic lymphocytic leukemia have symptoms. In some cases, the disease progresses slowly before symptoms develop. Due to this, doctors partly base the diagnosis of chronic lymphocytic leukemia on the level of lymphocytes in the blood.
There are two main types of lymphocytes: T cells and B cells. Both types of lymphocytes are part of the immune system and help the body fight viruses, bacteria, and other pathogens.
The classification of chronic lymphocytic leukemia depends on the type of lymphocyte affected. The two main forms are B-cell chronic lymphocytic leukemia and T-cell prolymphocytic leukemia.
B-cell chronic lymphocytic leukemia affects the B cells and is the most common form of the disease. T-cell prolymphocytic leukemia is a rare cancer that has a higher prevalence among males and older adults.
A normal lymphocyte range for adults is anywhere between 1,000 and 4,800 cells in 1 microliter (μl) of blood. A diagnosis of chronic lymphocytic leukemia requires a lymphocyte level of greater than or equal to 5,000 B cells per μl for a minimum of 3 months. Doctors refer to abnormally high lymphocyte levels as lymphocytosis.
When someone develops chronic lymphocytic leukemia, they have a higher level of lymphocytes. However, these cells do not work as they should, so they do not fight infection properly.
Although a lymphocyte level of greater than or equal to 5,000 B cells helps doctors make a diagnosis, it does not appear to determine a person’s outlook.
Instead, researchers use staging systems for this purpose. A standard staging system for chronic lymphocytic leukemia is the Rai staging system, in which a lower stage indicates a better outlook.
All stages include lymphocytosis. They also include the following:
- Rai stage 0: No spleen, liver, or lymph enlargement, with platelet and red blood cell counts near normal.
- Rai stage 1: Enlarged lymph nodes, but liver and spleen not enlarged, and platelet and red blood cell counts near normal.
- Rai stage 2: Enlarged spleen and possibly enlarged lymph nodes, but platelet and red blood cell counts near normal.
- Rai stage 3: Possibly enlarged liver, lymph nodes, or spleen, and red blood cell count is low, but platelet count is close to normal.
- Rai stage 4: Enlarged lymph nodes, liver, or spleen, low platelet count, and red blood cell count may also be low.
Chronic lymphocytic leukemia often progresses slowly. In many cases, the cancer is not curable, but treatment helps keep the symptoms at bay and slows the progression of the disease.
Not all people with chronic lymphocytic leukemia start treatment immediately after diagnosis. One factor in determining when to start treatment is the level of lymphocytes.
According to research in the
The presence of symptoms of leukemia also indicates the need for treatment to start.
Doctors find lymphocyte counts through a B- and T-cell screen. This test involves a blood draw to measure the level of lymphocytes.
A lymphocyte count is part of a complete blood count, which measures red blood cells and platelets, as well as white blood cells. Doctors often order a complete blood count to help diagnose various types of illnesses and infections.
After finding an abnormally high lymphocyte level, a doctor may order a peripheral blood smear. This test looks at the maturity and form of the blood cells, providing the doctor with more information on the cause of high lymphocytes.
If the doctor suspects cancer, a bone marrow biopsy is an option. A bone marrow biopsy involves removing a small amount of bone marrow, often from the hip bone, and sending it to a laboratory for analysis. The size, shape, and other traits of the cells help doctors determine a diagnosis.
If a person has an abnormally high lymphocyte count, they should see their doctor. Depending on the underlying cause of the increased count, additional symptoms may occur.
For example, if high lymphocytes occur due to leukemia, the person may experience:
- recurrent infections
- shortness of breath
- night sweats
Although a high lymphocyte count can indicate chronic lymphocytic leukemia, it can also occur due to other conditions. In some cases, abnormally high lymphocyte levels can develop as a normal part of the body’s response to an infection. For instance, a viral infection, such as the flu, may lead to increased lymphocytes.
The outlook for people with chronic lymphocytic leukemia often depends on the stage.
According to the American Cancer Society, chronic lymphocytic leukemia is usually difficult to cure. However, people with chronic lymphocytic leukemia often live many years after their diagnosis.
The 5-year relative survival rate for people with chronic lymphocytic leukemia is about
The number of lymphocytes, a type of white blood cell, increases with certain types of cancers. Therefore, a lymphocyte count of more than 5,000 B cells per μl of blood indicates the possibility of cancer.
However, increased lymphocytes also occur with other conditions, such as infections and inflammatory diseases.
Not everyone with chronic lymphocytic leukemia will require immediate treatment, but when lymphocyte levels increase quickly, this may indicate an advanced stage of cancer and the need for prompt treatment.