Chronic lymphocytic leukemia is cancer of the white blood cells (lymphocytes).

See also:

• Acute lymphocytic leukemia (ALL)
• Chronic myelogenous leukemia (CML)
• Leukemia

Chronic lymphocytic leukemia (CLL) causes a slow increase in the number of white blood cells called B cells in the bone marrow. The cancerous cells spread from the blood marrow to the blood, and can also affect the lymph nodes and other organs. CLL eventually causes the bone marrow to fail and weakens the immune system.

The reason for this increase in B cells is unknown. There is no link to radiation, cancer-causing chemicals, or viruses.

CLL primarily effects adults. The average age of patients with this type of leukemia is 70. It is rarely seen in people younger than 40. The disease is more common in Jewish people of Russian or East European descent, and is uncommon in Asians.

Symptoms usually develop gradually. Many cases of CLL are detected by routine blood tests in people who do not have any symptoms.

Symptoms that can occur include:

• Abnormal bruising (occurs late in the disease)
• Enlarged lymph nodes, liver, or spleen
• Excessive sweating, night sweats
• Fatigue
• Fever
• Infections that keep coming back (recur)
• Loss of appetite or becoming full too quickly (early satiety)
• Unintentional weight loss