Definition
Hairy cell leukemia (HCL) is a rare form of cancer. It involves white blood cells called B lymphocytes. White blood cells protect the body from infections and cancers. HCL gets its name from the tiny hair-like projections that protrude from the surface of these cancer cells. Illness results from the accumulation of these cancer cells in the bone marrow and spleen.
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.
White Blood Cells

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