Blood consists of red blood cells that carry nutrients and oxygen, white blood cells that provide immunity and platelets that induce blood to clot. The bone marrow, a spongy material found in some bones, contains stem cells that develop into new blood cells at a rate of about 100 billion cells per day, according to the Merck Manual. Conditions and diseases that affect the bone marrow or that attack the blood can reduce the number of platelets and white blood cells causing a variety of effects.
Platelet Functions
Platelets possess several unique characteristics. They are small, lack a nucleus, make up less than one percent of the total number of cells in the blood and stick to one another and other cells, according to The University Hospital, allowing them to perform their classic function of promoting blood to clot. In addition, because platelets circulate along the blood vessel walls, they can respond quickly to the site of vascular injury. Horstman et. al in the 2010 issue of the "Journal of Neuroinflammation" reveals that platelets also function in inflammation, immunity and tissue repair.
White Cell Functions
Because white blood cells consist of five different types of specialized cells that provide specific functions in the immune system, a low white-cell count causes many effects. Neutrophils protect the body from acute bacteria, as well as some fungal infections, according to the Merck Manual. Lymphocytes fight infections and provide immunity. Monocytes remove dead or damaged tissue, destroy cancer cells and help regulate immunity, according to the Merck Manual. Eosinophils protect against certain parasites and aid in inflammation, while basophils aid in wound repair and function in allergic reactions.
Associated Diseases
Disorders affecting the stem cells in the bone marrow can cause a decrease in the number of platelets and white blood cells. Anaplastic anemia occurs when stem cells become damaged, inhibiting the production of blood cells. The group of disorders known as myelodysplastic syndrome cause the new blood cells to die while still in the bone marrow or shortly after entering the bloodstream. Some viruses, such as the human immunodeficiency virus, destroy white blood cells. Chemotherapy, the use of drugs to destroy cancer cells, can also destroy stem cells, resulting in a low platelet and low white count.
Thrombocytopenia
Thrombocytopenia, the medical term for a low platelet count, decreases the ability of blood to clot leading to an increase in superficial bleeding and prolonged bleeding even in minor cuts, according to MayoClinic.com. Other effects include excessive bruising, spontaneous bleeding, blood in the urine and profuse bleeding during surgical procedures.
Leukopenia
One microliter of blood should contain between 4,000 to 11,000 white blood cells, according to the Merck Manual. Doctors diagnose those patients with fewer than 4,000 white blood cells with the condition leucopenia. The effects of leucopenia depend upon the severity of the disorder. Mild cases may cause no apparent symptoms as the immune system remains intact. As the number of white blood cells decreases further, however, the patient becomes vulnerable to frequent infections resulting in fevers, mouth ulcers, inflammation of the mucus membranes and pneumonia.
