Leukemia, chronic lymphocytic

The most common form of leukemia in adults, in which the lymphocytes may look fairly normal but are not fully mature and do not deal effectively with infection.

The malignant cells are found in the blood and bone marrow, collect in and enlarge the lymph nodes, and may crowd out other blood cells in the bone marrow, resulting in a shortage of red blood cells (producing anemia) and platelets (producing easy bruising and bleeding).

Abbreviated CLL.

CLL is most common in people over 60 and progresses slowly.

In the first stages, there are often no symptoms.

As time goes on, more and more lymphocytes are made and symptoms begin to appear such as a persistent feeling of fatigue, swelling of the lymph nodes, enlargement of the spleen and liver, and easy bruising and bleeding.

Treatment may include chemotherapy, radiation, leukapheresis (a procedure to remove the extra lymphocytes) and bone marrow transplantation.

CLL is an enigmatic type of leukemia in that the clinical course and outcome vary considerably from patient to patient, and therefore the outlook is unpredictable.

About two-thirds of patients live with the disease for decades and die from other causes while about a third of patients experience difficulties soon after diagnosis, require frequent and often multiple forms of therapy, yet succumb to the illness within a few years.

Cells that make a protein called ZAP-70 are more common in cases of CLL with poor outcomes.

The capacity to make ZAP-70 protein appears limited to CLL cells with unmutated immunoglobulin genes.

Detection of ZAP-70 can now be done by a relatively convenient and clinically available technology.