Chronic Lymphocytic Leukemia

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It is possible that the main title of the report Chronic Lymphocytic Leukemia is not the name you expected.

Disorder Subdivisions

  • None

General Discussion

Chronic lymphocytic leukemia (CLL) is a malignant blood disorder in which there are an increased number of white blood cells in the lymphoid tissue. In CLL, the abnormal lymphocytes, also called leukemic cells, are produced instead of healthy white blood cells, and then accumulate over time. As the number of unhealthy blood cells grows, there is less room for healthy cells. The combination of fewer healthy cells, and the fact that the CLL lymphocytes are poor at fighting infections can lead to frequent infection, anemia, and easy bleeding. This disease progresses slowly, and the uncontrolled buildup and enlargement of lymphoid tissue can occur in various sites of the body such as the lymph nodes, spleen, bone marrow, and lungs. CLL is the most common type of leukemia in adults and very rarely occurs in children.

In the majority of cases, chronic lymphocytic leukemia is the result of a rapid production of B lymphocyte cells (a short-lived type of white blood cell that is responsible for the production of vertebrate serum proteins that include antibodies). What was previously called CLL derived from T lymphocytes has been renamed as another disorder, T cell prolymphocytic leukemia. The overgrowth of cells in this T-cell disease tends to be much faster.

The ability to distinguish between cells that have unmutated IgVH (Ig-unmutated CLL) and mutated IgVH (Ig-mutated CLL) has become very important in predicting the course of the disease (prognosis). Patients who have Ig-unmutated CLL have a much shorter average survival period of about 7 years compared to Ig-mutated CLL patients, whose average survival period is about 25 years. These survival times however are based on older data and likely longer now, with improved therapies. A protein called ZAP-70 is correlated with the IGVH status about 75% of the time but also provides independent prognostic information. Determining the subset of CLL based on IGVH status is important because it predicts prognosis. Because CLL usually progresses so slowly, many patients do not need immediate treatment and some do not even require it in their lifetime. Treatment is still based primarily on symptoms or worsening blood counts, not on these prognostic factors.

Supporting Organizations

American Cancer Society, Inc.

250 Williams NW St
Ste 6000
Atlanta, GA 30303
Tel: (404)320-3333
Tel: (800)227-2345

Cancer Research UK

Angel Building
407 St John Street
London, EC1V 4AD
United Kingdom
Tel: 020 7242 0200
Fax: 2071216700

Cancer Support Community

1050 17th St NW Suite 500
Washington, DC 20036
Tel: (202)659-9709
Fax: (202)974-7999
Tel: (888)793-9355


American Society of Clinical Oncology
2318 Mill Road Suite 800
Alexandria, VA 22314
Tel: (571)483-1780
Fax: (571)366-9537
Tel: (888)651-3038

Children's Leukemia Research Association

585 Stewart Avenue, Suite 18
Garden City, NY 11530
Tel: (516)222-1944
Fax: (516)222-0457

Friends of Cancer Research

1800 M Street NW
Suite 1050 South
Washington, DC 22202
Tel: (202)944-6700

Genetic and Rare Diseases (GARD) Information Center

PO Box 8126
Gaithersburg, MD 20898-8126
Tel: (301)251-4925
Fax: (301)251-4911
Tel: (888)205-2311

Leukemia & Lymphoma Society

1311 Mamaroneck Avenue
Suite 310
White Plains, NY 10605
Tel: (914)949-5213
Fax: (914)949-6691
Tel: (800)955-4572

Livestrong Foundation

2201 E. Sixth Street
Austin, TX 78702
Tel: (512)236-8820
Fax: (512)236-8482
Tel: (877)236-8820

Lymphoma Research Foundation

115 Broadway
Suite 1301
New York, NY 10006
Tel: (212)349-2910
Fax: (212)349-2886
Tel: (800)235-6848

National Cancer Institute

6116 Executive Blvd Suite 300
Bethesda, MD 20892-8322
Tel: (301)435-3848
Tel: (800)422-6237

OncoLink: The University of Pennsylvania Cancer Center Resource

3400 Spruce Street
2 Donner
Philadelphia, PA 19104-4283
Tel: (215)349-8895
Fax: (215)349-5445

Rare Cancer Alliance

1649 North Pacana Way
Green Valley, AZ 85614

For a Complete Report

This is an abstract of a report from the National Organization for Rare Disorders (NORD). For a full-text version of this report, go to and click on Rare Disease Database under "Rare Disease Information".

The information provided in this report is not intended for diagnostic purposes. It is provided for informational purposes only.

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This disease entry is based upon medical information available through the date at the end of the topic. Since NORD's resources are limited, it is not possible to keep every entry in the Rare Disease Database completely current and accurate. Please check with the agencies listed in the Resources section for the most current information about this disorder.

Last Updated:  8/5/2015
Copyright  2011 National Organization for Rare Disorders, Inc.