Definition

Chronic lymphocytic leukemia (CLL) is a cancer of the blood and bone marrow. Lymphocytes are a type of white blood cell. With CLL the bone marrow makes too many of these cells. CLL begins in mature lymphocytes. It progresses gradually. It may be indolent (slow growing) for many years. You may have little or no trouble. It may also eventually progress to a more aggressive form of leukemia, acute lymphoblastic leukemia (ALL). Some forms of CLL may be more serious. This is because leukemia involves the cells of the immune system. These cells that are needed to resist infection.

White Blood Cells

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Cancer occurs when cells in the body become abnormal. They divide without control or order. Leukemia is cancer of the white blood cells and their parent cells. Leukemia cells do not function normally. They cannot do what normal blood cells do. In this case they can not fight infections. This means that the person is more likely to become infected with viruses or bacteria. The cancerous cells also overgrow the bone marrow. This forces other normal components, like platelets out. Platelets are needed to help the blood clot. As a result, people with leukemia may bleed more easily.

CLL can also be associated with the presence of chronic lymphocytic lymphoma. This is a small cell non-Hodgkin’s lymphoma . The abnormal cells in both cases may come from the same parent cell source. As a result, one of the signs of CLL may be a swelling in the lymph nodes.