What Is Leukemia?
The world breaks everyone and afterward many are strong at the broken places.
-Ernest Hemingway A Farewell to Arms
THE WORD LEUKEMIA literally means 'white blood.' Leukemia is the term used to describe a variety of cancers that begin in the blood-forming tissues of the bone marrow, the spongy material that fills the long bones in the body and produces blood cells. In leukemia, the bone marrow factory creates an overabundance of diseased white cells that cannot perform their normal function of fighting infection. As the bone marrow floods the bloodstream with diseased white cells, production of red cells (which prevent anemia) and platelets (which form clots to stop bleeding) slows and stops.
To better understand leukemia, it is necessary to become familiar with the function and composition of blood. Leukemia is a disease of the blood
Blood is a vital liquid, which supplies oxygen, food, hormones, and other necessary chemicals to all of the body's cells. It removes toxins and other waste products from the cells. Blood helps the lymph system to fight infection and carries the cells necessary for repairing injuries.
Whole blood is made up of plasma, which is a clear fluid, and many other components, each with a specific task. The three main elements involved in leukemia are red blood cells, platelets, and white blood cells.
Red blood cells (erythrocytes or RBCs) contain hemoglobin, a protein which picks up oxygen in the lungs and transports it throughout the body RBCs give blood its red color. When leukemia cells in the bone marrow slow down the production of red cells, the child develops anemia. Anemia can cause weakness, irritability, pale skin, and shortness of breath.
Platelets (thrombocytes) are tiny, disc-shaped cells which help form clots to stop bleeding. Leukemia can dramatically slow down the production of platelets, causing children to bleed excessively from cuts or in some cases from their nose or gums. Children with leukemia usually develop large bruises; sometimes small red dots (called petechiae) cover their skin.
White blood cells (leukocytes or WBCs) destroy foreign substances in the body such as viruses, bacteria, and fungi. They are produced and stored in the bone marrow and are released when needed by the body. If an infection is present, the body produces extra WBCs.
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Theses cells contain enzymes that kill foreign bacteria. |
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: There are two types that interact to prevent infection and provide immunity to disease: |
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T-cells attack infected cells, foreign tissue, and cancer cells. |
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B-cells produce antibodies which destroy foreign substances. |
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There are three types that are the first defense against infection: |
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Neutrophils are the most numerous WBCs and are the first to respond to foreign bacteria. |
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Eosinophils respond to allergic reactions as well as foreign bacteria. |
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Basophils are the rarest of the white cells and play a special role in allergic reactions. |
The different types of leukemia are cancers of a specific white blood cell type. For instance, acute lymphoblastic leukemia affects only lymphocytes.
"Blast" is a short name for an immature white blood cell such as lymphoblast, myeloblast, or monoblast. Normally, less than five percent of the cells contained in healthy bone marrow at any one time are blasts. Normal blasts develop into mature, functioning white blood cells, and are not usually found in the bloodstream. Leukemic blasts remain immature, multiply continuously, provide no defense against infection, and may be present in large numbers in the bloodstream.
