Overview

Chronic lymphocytic leukemia (CLL) is a type of cancer of the blood and bone marrow — the spongy tissue inside bones where blood cells are made.

The term "chronic" in chronic lymphocytic leukemia comes from the fact that this leukemia typically progresses more slowly than other types of leukemia. The term "lymphocytic" in chronic lymphocytic leukemia comes from the cells affected by the disease — a group of white blood cells called lymphocytes, which help your body fight infection.

Chronic lymphocytic leukemia most commonly affects older adults. There are treatments to help control the disease.

Symptoms

Many people with chronic lymphocytic leukemia have no symptoms at first. Signs and symptoms might develop as the cancer progresses. They might include:

  • Enlarged, but painless, lymph nodes
  • Fatigue
  • Fever
  • Pain in the upper left portion of the abdomen, which may be caused by an enlarged spleen
  • Night sweats
  • Weight loss
  • Frequent infections

When to see a doctor

Make an appointment with your doctor if you have any persistent signs and symptoms that worry you.

Causes

Doctors aren't certain what starts the process that causes chronic lymphocytic leukemia. What's known is that something happens to cause changes (mutations) in the DNA of blood-producing cells. A cell's DNA contains the instructions that tell the cell what to do. The changes tell the blood cells to produce abnormal, ineffective lymphocytes.

Beyond being ineffective, these abnormal lymphocytes continue to live and multiply when healthy lymphocytes would die. The abnormal lymphocytes accumulate in the blood and certain organs, where they cause complications. They may crowd healthy cells out of the bone marrow and interfere with blood cell production.

Doctors and researchers are working to understand the exact mechanism that causes chronic lymphocytic leukemia.

Risk factors

Factors that may increase the risk of chronic lymphocytic leukemia include:

  • Your age. This disease occurs most often in older adults.
  • Your race. White people are more likely to develop chronic lymphocytic leukemia than are people of other races.
  • Family history of blood and bone marrow cancers. A family history of chronic lymphocytic leukemia or other blood and bone marrow cancers may increase your risk.
  • Exposure to chemicals. Certain herbicides and insecticides, including Agent Orange used during the Vietnam War, have been linked to an increased risk of chronic lymphocytic leukemia.
  • A condition that causes excess lymphocytes. Monoclonal B-cell lymphocytosis (MBL) causes an increased number of one type of lymphocyte (B cells) in the blood. For a small number of people with MBL, the condition may develop into chronic lymphocytic leukemia. If you have MBL and also have a family history of chronic lymphocytic leukemia, you may have a higher risk of developing cancer.

Complications

Chronic lymphocytic leukemia may cause complications such as:

  • Frequent infections. If you have chronic lymphocytic leukemia, you may experience frequent infections that can be serious. Sometimes infections happen because your blood doesn't have enough germ-fighting antibodies (immunoglobulins). Your doctor might recommend regular immunoglobulin infusions.
  • A switch to a more aggressive form of cancer. A small number of people with chronic lymphocytic leukemia may develop a more aggressive form of cancer called diffuse large B-cell lymphoma. Doctors sometimes refer to this as Richter's syndrome.
  • Increased risk of other cancers. People with chronic lymphocytic leukemia have an increased risk of other types of cancer, including skin cancer and cancers of the lung and the digestive tract.
  • Immune system problems. A small number of people with chronic lymphocytic leukemia may develop an immune system problem that causes the disease-fighting cells of the immune system to mistakenly attack the red blood cells (autoimmune hemolytic anemia) or the platelets (autoimmune thrombocytopenia).

Chronic lymphocytic leukemia care at Mayo Clinic

April 27, 2023

Living with chronic lymphocytic leukemia?

Connect with others like you for support and answers to your questions in the Blood Cancers & Disorders support group on Mayo Clinic Connect, a patient community.

Blood Cancers & Disorders Discussions

rhawk314
Mast Cell Activation Syndrome: What treatments help you?

30 Replies Mon, Mar 18, 2024

naiviv
Immune Thrombocytopenia Purpura (ITP): What helps?

154 Replies Mon, Mar 18, 2024

cindylb
Anyone have Cutaneous T Cell Lymphoma?

148 Replies Mon, Mar 18, 2024

See more discussions
  1. Niederhuber JE, et al., eds. Chronic lymphocytic leukemia. In: Abeloff's Clinical Oncology. 6th ed. Elsevier; 2020. https://www.clinicalkey.com. Accessed April 13, 2021.
  2. Kaushansky K, et al., eds. Chronic lymphocytic leukemia. In: Williams Hematology. 10th ed. McGraw Hill; 2021. https://accessmedicine.mhmedical.com. Accessed April 13, 2021.
  3. AskMayoExpert. Chronic lymphocytic leukemia (CLL) (adult). Mayo Clinic; 2019.
  4. Chronic lymphocytic leukemia/small lymphocytic leukemia. National Comprehensive Cancer Network. https://www.nccn.org/guidelines/guidelines-detail?category=1&id=1478. Accessed April 13, 2021.
  5. Chronic lymphocytic leukemia treatment (PDQ) — Patient version. National Cancer Institute. https://www.cancer.gov/types/leukemia/patient/cll-treatment-pdq. Accessed April 13, 2021.
  6. Cancer-related fatigue. National Comprehensive Cancer Network. https://www.nccn.org/guidelines/guidelines-detail?category=3&id=1424. Accessed April 13, 2021.
  7. Warner KJ. Allscripts EPSi. Mayo Clinic. Feb. 8, 2021.
  8. Shanafelt TD, et al. Hematologist/oncologist disease-specific expertise and survival: Lessons from chronic lymphocytic leukemia (CLL)/small lymphocytic leukemia (SLL). Cancer. 2012; doi:10.1002/cncr.26474.
  9. Ding W, et al. Pembrolizumab in patients with CLL and Richter transformation or with relapsed CLL. Blood. 2017; doi:10.1182/blood-2017-02-765685.
  10. Archibald WJ, et al. Atrial fibrillation in patients with chronic lymphocytic leukemia (CLL) treated with ibrutinib: Risk prediction, management and clinical outcomes. Annals of Hematology. 2021; doi:10.1007/s00277-020-04094-3.
  11. Lymphoma SPOREs. National Cancer Institute. https://trp.cancer.gov/spores/lymphoma.htm. Accessed April 23, 2021.
  12. Sites. Chronic lymphocytic leukemia Research Consortium (CRC). https://cll.ucsd.edu/research-sites. Accessed April 23, 2021.
  13. Slager SL, et al. Natural history of monoclonal B-cell lymphocytosis among relatives in CLL families. Blood. 2021; doi:10.1182/blood.2020006322.