White blood cells (WBCs), also known as leukocytes, are a crucial component of the immune system and play a key role in defending the body against infections and foreign invaders. They are produced in the bone marrow and circulate throughout the bloodstream, where they can travel to sites of infection and inflammation to combat pathogens.
Abnormal levels of white blood cells can provide important diagnostic information and may indicate the presence of an underlying health issue. For example, an elevated white blood cell count (leukocytosis) is often seen in response to infections, while a low white blood cell count (leukopenia) can be caused by various factors, including bone marrow disorders, chemotherapy, or autoimmune conditions.
Several types:
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Neutrophils: Neutrophils are the most abundant type of white blood cell and are often the first responders to infection. They engulf and destroy bacteria and other pathogens.
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Lymphocytes: Lymphocytes are a diverse group of white blood cells that include B cells and T cells. B cells produce antibodies, which target and neutralize pathogens. T cells assist in the immune response, directly attacking infected cells, and regulating the immune system.
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Monocytes: Monocytes are large white blood cells that can transform into macrophages when they migrate into tissues. Macrophages engulfing and break down pathogens and cellular debris.
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Eosinophils: Eosinophils defend against parasitic infections and are also involved in the immune response to allergies, asthma, and certain autoimmune diseases.
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Basophils: Basophils release histamine and other chemicals that can trigger inflammation and allergic reactions. They play a role in immediate hypersensitivity responses.