Print OverviewChronic lymphocytic leukemia (CLL) is a type of leukemia. Leukemia is cancer that affects the blood and bone marrow. Bone marrow is the spongy tissue inside bones where blood cells are made. The term "chronic" in chronic lymphocytic leukemia refers to the slower progression of this cancer. CLL typically progresses more slowly than other types of leukemia. The term "lymphocytic" refers to the cells affected by the disease. The cells are a group of white blood cells called lymphocytes. Lymphocytes help your body fight infection. Treatments for chronic lymphocytic leukemia may include a "watch and wait" approach, targeted therapy, chemotherapy, immunotherapy and bone marrow transplant, also known as bone marrow stem cell transplant. Other treatment options may include CAR-T cell therapy, radiation therapy and clinical trials. Dr. Rafael Fonseca, hematologist and Chief Innovation Officer at Mayo Clinic Call your preferred Mayo Clinic location: Arizona: Florida: Minnesota: Products & ServicesA Book: Living MedicineA Book: Mayo Clinic Family Health BookNewsletter: Mayo Clinic Health Letter — Digital EditionShow more products from Mayo Clinic SymptomsChronic lymphocytic leukemia symptoms may not happen right away. Symptoms may develop as the cancer progresses. When symptoms happen, they may include: Swollen lymph nodes, which might feel like a lump under the skin. They happen most often in the neck, armpit and groin. Fever. Drenching night sweats. Fatigue. Weight loss without trying. Loss of appetite. Pain in the upper left part of the belly, which may be caused by an enlarged spleen. Frequent infections. When to see a doctorMake an appointment with a healthcare professional if you have any symptoms that worry you. Request an appointment CausesIt's not clear what causes chronic lymphocytic leukemia. Cancer happens when cells develop changes in their DNA. A cell's DNA holds the instructions that tell the cell what to do. In healthy cells, the DNA gives instructions to grow and multiply at a set rate. The instructions tell the cells to die at a set time. In cancer cells, the DNA changes give different instructions. The changes tell the cancer cells to make many more cells quickly. Cancer cells can keep living when healthy cells would die. This causes too many cells. In chronic lymphocytic leukemia, the cancer cells can build up in the blood, bone marrow, lymph nodes and other parts of the body. Risk factorsFactors that may increase the risk of chronic lymphocytic leukemia include: Your age. Chronic lymphocytic leukemia happens most often in adults older than 55. 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 a type of lymphocyte, called B lymphocytes, 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. ComplicationsChronic lymphocytic leukemia may cause complications such as: Frequent infections. If you have chronic lymphocytic leukemia, you may get infections more often. These infections can be serious. Sometimes infections happen because your blood doesn't have enough germ-fighting antibodies, called immunoglobulins. Your healthcare professional 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. This is sometimes referred to as Richter syndrome. Increased risk of other cancers. People with chronic lymphocytic leukemia have an increased risk of other types of cancer. These include skin cancer and cancers of the lung and the digestive tract. Immune system attacks. A small number of people with chronic lymphocytic leukemia may develop an immune system reaction that causes the disease-fighting cells of the immune system to mistakenly attack the red blood cells. This is called autoimmune hemolytic anemia. The immune system also may attack the blood cells that help blood clot, called platelets. This attack is called autoimmune thrombocytopenia. By Mayo Clinic Staff Chronic lymphocytic leukemia care at Mayo Clinic Request an appointment Diagnosis & treatment Oct. 24, 2025 Print 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 Want to talk about Multiple Myeloma: Anyone else? 424 Replies Wed, Oct 29, 2025 chevron-right Will soon have a Bone Marrow Transplant: What can I expect? 28 Replies Tue, Oct 28, 2025 chevron-right Living with MDS (Myelodyplastic Syndromes) 233 Replies Tue, Oct 28, 2025 chevron-right See more discussions Show references Niederhuber JE, et al., eds. Chronic lymphocytic leukemia. In: Abeloff's Clinical Oncology. 6th ed. Elsevier; 2020. https://www.clinicalkey.com. Accessed Sept. 8, 2025. Kaushansky K, et al., eds. Chronic lymphocytic leukemia. In: Williams Hematology. 10th ed. McGraw Hill; 2021. https://accessmedicine.mhmedical.com. Accessed Sept. 8, 2025. Stilgenbauer S. Overview of the complications of chronic lymphocytic leukemia. https://www.uptodate.com/contents/search. Accessed Sept. 8, 2025. Chronic lymphocytic leukemia/small lymphocytic leukemia. National Comprehensive Cancer Network. https://www.nccn.org/guidelines/guidelines-detail?category=1&id=1478. Accessed Sept. 8, 2025. Chronic lymphocytic leukemia treatment (PDQ) — Patient version. National Cancer Institute. https://www.cancer.gov/types/leukemia/patient/cll-treatment-pdq. Accessed Sept. 8, 2025. Chronic lymphocytic leukemia (CLL). Blood Cancer United. https://bloodcancerunited.org/blood-cancer/leukemia/chronic-lymphocytic-leukemia-cll. Accessed Sept. 8, 2025. Rosenthal DS, et al. Evaluation of the peripheral blood smear. https://www.uptodate.com/contents/search. Accessed Sept. 8, 2025. Targeted therapy to treat cancer. National Cancer Institute. https://www.cancer.gov/about-cancer/treatment/types/targeted-therapies. Accessed Sept. 8, 2025. Chemotherapy to treat cancer. National Cancer Institute. https://www.cancer.gov/about-cancer/treatment/types/chemotherapy#chemotherapy-can-cause-side-effects. Accessed Sept. 8, 2025. Immunotherapy side effects. National Cancer Institute. https://www.cancer.gov/about-cancer/treatment/types/immunotherapy/side-effects. Accessed Sept. 8, 2025. Radiation therapy side effects. National Cancer Institute. https://www.cancer.gov/about-cancer/treatment/types/radiation-therapy/side-effects. Accessed Sept. 8, 2025. Stem cell transplants in cancer treatments. National Cancer Institute. https://www.cancer.gov/about-cancer/treatment/types/stem-cell-transplant#stem-cell-transplant-side-effects. Accessed Sept. 8, 2025. T-cell transfer therapy. National Cancer Institute. https://www.cancer.gov/about-cancer/treatment/types/immunotherapy/t-cell-transfer-therapy. Accessed Sept. 8, 2025. Cancer-related fatigue. National Comprehensive Cancer Network. https://www.nccn.org/guidelines/guidelines-detail?category=3&id=1424. Accessed Sept. 8, 2025. Cancer stat facts: Leukemia — chronic lymphocytic leukemia (CLL). National Cancer Institute. https://seer.cancer.gov/statfacts/html/clyl.html. Accessed Sept. 8, 2025. Warner KJ. Allscripts EPSi. Mayo Clinic. Feb. 8, 2021. 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. 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. Elsevier Point of Care. Clinical Overview: Febrile neutropenia in adults. https://www.clinicalkey.com. Accessed Sept. 8, 2025. Larson RA, et al. Tumor lysis syndrome: Prevention and treatment. https://www.uptodate.com/contents/search. Accessed Sept. 8, 2025. Related Associated Procedures Bone marrow biopsy Bone marrow transplant Cancer treatment CAR-T cell therapy Chemotherapy Complete blood count (CBC) CT scan Show more associated procedures Products & Services A Book: Living Medicine A Book: Mayo Clinic Family Health Book Newsletter: Mayo Clinic Health Letter — Digital Edition Show more products and services from Mayo Clinic Mayo Clinic in Rochester, Minnesota, Mayo Clinic in Jacksonville, Florida, and Mayo Clinic in Phoenix/Scottsdale, Arizona, have been recognized among the top Cancer hospitals in the nation by U.S. News & World Report. Learn more about this top honor Chronic lymphocytic leukemiaSymptoms&causesDiagnosis&treatmentStagesSurvivalratesDoctors&departmentsCare atMayoClinic Advertisement Mayo Clinic does not endorse companies or products. Advertising revenue supports our not-for-profit mission. 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