Chronic lymphocytic leukemia (CLL) is a form of cancer that leads to an atypically high level of lymphocytes within the bone marrow. Tests, such as a bone marrow biopsy, can determine how advanced CLL is.

Bone marrow contains many different substances, including lymphocytes. These are a type of white blood cell that can help the body fight infection. In chronic leukemia, the white blood cells in the bone marrow mature partially and begin building up. This buildup can cause problems.

A bone marrow transplant may benefit some people with CLL, especially if they are otherwise healthy.

This article explores the relationship between CLL and bone marrow. It also describes the use of bone marrow biopsies and transplants.

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Leukemia originates from blood-forming tissues, such as the bone marrow. The bone marrow is a spongy tissue found within the center of many bones. It contains a variety of cells, including stem cells. Stem cells can turn into different types of cells in the body.

Two types of bone marrow exist: red and yellow.

Red bone marrow contains stem cells that can become:

  • red blood cells, which carry oxygen and other substances around the body
  • white blood cells, which help the body fight infection
  • platelets, which help the blood clot

Yellow bone marrow contains stem cells that can become:

  • cartilage, a tissue that protects joints and other areas in the body
  • fat
  • bone cells

The United Kingdom’s National Health Service (NHS) explains that the bone marrow produces too many lymphocytes in CLL. However, these cells do not fully develop and tend not to work properly.

Many people with CLL may not experience any symptoms at all. They may only receive a diagnosis after taking a routine blood test, usually for another condition.

When people do experience symptoms, they can be mild at first and slowly worsen. In some cases, CLL may gradually lead to:

After diagnosing CLL, a doctor will decide whether a person requires treatment. Typically, people with no symptoms may only require monitoring. Immediate treatment may benefit those with symptoms or an advanced stage of CLL.

Learn more about CLL here.

Bloodwork can reveal that a person has an atypically high white blood cell count. This might lead doctors to suspect they have CLL.

Doctors may perform tests on the bone marrow to help determine how advanced the condition is and guide treatment if necessary. These include bone marrow aspiration, in which a doctor inserts a needle into the bone and takes out a sample of the fluid and cells using a syringe. This may cause sharp pain.

A bone marrow biopsy involves inserting a biopsy needle into the bone to take a sample of the bone and the bone marrow tissue, which may cause pressure or pain.

A doctor will usually perform both tests together and may offer a mild sedative beforehand. They may also check the individual’s blood pressure and heart rate.

Individuals can take pain medications to relieve any stiffness and soreness in the affected area. However, doctors may advise against using aspirin, which may increase bleeding risk.

A doctor may repeat bone marrow aspiration and biopsies throughout a person’s treatment course.

Learn more about how doctors diagnose CLL here.

A person with CLL may need a bone marrow transplant or stem cell transplant if their cancer has a high chance of returning or there have been no improvements with other treatments.

The procedure involves replacing bone marrow cells that cancer or cancer treatment has destroyed.

Stem cells for the procedure may come from the bone marrow or blood of the person or a donor. These can help produce new, healthy cells in the body.

This kind of transplant helps treat conditions affecting the bone marrow, such as:


Before a bone marrow transplant, the doctor will ensure that a person can handle the transplant process. This may involve taking a medical history and performing tests, such as:


The procedure may take place in an outpatient center or hospital. It generally involves the following steps:

  1. The individual with CLL receives high doses of radiation or chemotherapy to help make space in the bone marrow so the physician can insert new cells. The person may rest for a few days before the infusion.
  2. The person receives the stem cells through a central venous catheter. This is a thin tube that the medical team inserts into a vein, mainly for blood transfusions and intravenous treatments. During the infusion, people may experience some side effects, such as pain and chills.
  3. Following the transplant, the person undergoes frequent testing and close monitoring to ensure that the body accepts the transplanted stem cells.

Most of this process takes place while a person is in the hospital.


After the procedure, preventing complications is important. Therefore, a person may receive additional supportive care, for example, medications to prevent infection.

Learn more about stem cell transplants and their associated risks here.

Below are answers to some commonly asked questions about CLL.

Can CLL spread to the bones?

CLL primarily affects the bone marrow and leads to atypically high amounts of lymphocytes within it. These cells may grow out of control and eventually enter the bloodstream, where they may travel to other body parts.

According to the National Cancer Institute, CLL can spread to the spleen, liver, and lymph nodes.

What is the outlook for a person with CLL?

A person’s outlook can depend on many factors, and there can be a large variation among individuals.

Although a person with CLL has a median survival period of 10 years, they could live much longer. Those with anemia and a low platelet count have a higher chance of a less positive outlook.

Treatment is more likely to be effective in young adults and if CLL is still in its early stages.

Learn more about survival rates for CLL here.

Is CLL hereditary?

A person may have a high chance of developing CLL if they have a close relative who has had the condition. However, most people with a family history of CLL do not develop it.

People with CLL have high levels of lymphocytes, a type of white blood cell, in their bone marrow. In people with the condition, lymphocytes typically do not fully develop or function well.

Doctors may perform a bone marrow biopsy to help guide the treatment of CLL. A bone marrow transplant may be an option to replace damaged blood cells with healthy ones. However, this procedure poses some risks.