White+Blood+Cells

for facts: [] [] [] [|Voki]**White blood cells**, or **leukocytes** (also spelled "leucocytes," "leuco-" being Greek for white), are [|cells] of the [|immune system] involved in defending the body against both [|infectious disease] and foreign materials. Five[|[][|1][|]] different and diverse types of leukocytes exist, but they are all produced and derived from a [|multipotent] cell in the [|bone marrow] known as a [|hematopoietic stem cell]. Leukocytes are found throughout the body, including the [|blood] and [|lymphatic system]. [] white blood cells in a [|litre] of blood, making up approximately 1% of blood in a healthy adult [] The white blood cell count is done by counting the number of white blood cells in a sample of blood. A normal WBC is in the range of 4,000 to 11,000 cells per microliter. A low WBC is called [|leukopenia] [] A low white blood cell count, or leukopenia, is a decrease in disease-fighting cells (leukocytes) circulating in your blood[]

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