Leukemia, Chronic Lymphocytic
Basics
Description
- Chronic lymphocytic leukemia (CLL) is a monoclonal disorder characterized by a progressive accumulation of mature but functionally incompetent lymphocytes.
- Based on percentage of prolymphocytes, the disease may be regarded as CLL (<10% prolymphocytes), prolymphocytic leukemia (PLL; >55%), or CLL/PLL (>10% and <55%).
- Small lymphocytic lymphoma is a lymphoma variant of CLL.
- System(s) affected: hematologic, lymphatic, immunologic
Epidemiology
Incidence
- CLL represents the most common form of leukemia in adults in the United States (2021 incidence of 21,050).
- Second leading cause of death among adults with leukemia in the United States after acute myeloid leukemia
- CLL primarily affects elderly individuals, with median age of diagnosis being 70 years.
- Predominant sex: male > female (1.6:1); higher among Caucasians
Etiology and Pathophysiology
- The cell of origin in CLL is a clonal B cell arrested in the B-cell differentiation pathway, intermediate between pre–B cells and mature B cells. In the peripheral blood, these cells resemble mature lymphocytes.
- Genetic mutations leading to disrupted function and prolonged survival of affected lymphocytes are suspected but are not well known. The BCL2 proto-oncogene (suppressor of apoptosis or programmed cell death) is overexpressed in CLL.
Genetics
Familial cases are rare. CLL does occur at higher frequency among first-degree relatives of patients with the disease, and several somatic gene mutations have been identified at significantly higher rates among CLL patients (1).
Risk Factors
Uncertain; possible chronic immune stimulation is suspected; monoclonal B-cell lymphocytosis: 1% risk progression to CLL
Commonly Associated Conditions
- Immune system dysregulation is common.
- Autoimmune hemolytic anemia (AIHA)
- Immune thrombocytopenia purpura (ITP)
- Pure red cell aplasia (PRCA)
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Citation
Domino, Frank J., et al., editors. "Leukemia, Chronic Lymphocytic." 5-Minute Clinical Consult, 33rd ed., Wolters Kluwer, 2025. Medicine Central, im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/1688874/all/Leukemia__Chronic_Lymphocytic.
Leukemia, Chronic Lymphocytic. In: Domino FJF, Baldor RAR, Golding JJ, et al, eds. 5-Minute Clinical Consult. Wolters Kluwer; 2025. https://im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/1688874/all/Leukemia__Chronic_Lymphocytic. Accessed December 12, 2024.
Leukemia, Chronic Lymphocytic. (2025). In Domino, F. J., Baldor, R. A., Golding, J., & Stephens, M. B. (Eds.), 5-Minute Clinical Consult (33rd ed.). Wolters Kluwer. https://im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/1688874/all/Leukemia__Chronic_Lymphocytic
Leukemia, Chronic Lymphocytic [Internet]. In: Domino FJF, Baldor RAR, Golding JJ, Stephens MBM, editors. 5-Minute Clinical Consult. Wolters Kluwer; 2025. [cited 2024 December 12]. Available from: https://im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/1688874/all/Leukemia__Chronic_Lymphocytic.
* Article titles in AMA citation format should be in sentence-case
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T1 - Leukemia, Chronic Lymphocytic
ID - 1688874
ED - Domino,Frank J,
ED - Baldor,Robert A,
ED - Golding,Jeremy,
ED - Stephens,Mark B,
BT - 5-Minute Clinical Consult, Updating
UR - https://im.unboundmedicine.com/medicine/view/5-Minute-Clinical-Consult/1688874/all/Leukemia__Chronic_Lymphocytic
PB - Wolters Kluwer
ET - 33
DB - Medicine Central
DP - Unbound Medicine
ER -