Idiopathic thrombocytopenic purpura, known by its acronym ITP, is a blood condition and bleeding disorder. Individuals with ITP bleed easily because of the low number of platelets in the blood. Platelets are the blood's natural coagulant, helping cuts to heal and the blood to stop flowing at an injury.
Normal platelet count for a healthy individual is 130,000 platelets per cubic millimeter of blood. An individual with ITP has a platelet count that ranges around 50,000, and can fall as low as 30,000.
The idiopathic in ITP means of "no known origin" as there is not one definite cause.
Autoimmune Disorder
According to the National Heart, Lung and Blood Institute, ITP is most likely an autoimmune disorder. Over 80 autoimmune disorders are diagnosed each year, and ITP is one of them. An autoimmune disorder occurs when the body's antibodies mistakenly attack its own organs and systems, thinking they are infections. In ITP, an antibody attaches to the platelet, which tricks white blood cells into thinking the platelet is a foreign virus or bacteria. The immune system attacks the platelets like they are an infection, and the platelets are destroyed. With no platelets, bleeding in the body continues.
Platelet Suppression and Destruction
In addition to destroying platelets, ITP also reduces platelet production in the bone marrow. Platelets form in different parts of the body like the spleen and bone marrow. The spleen is part of the lymphatic system, helps fight infections, and holds one-third of the body's platelets. Doctors and researchers alike point to an autoantibody called cytotoxic T lymphocytes as the possible cause of this platelet suppression.
Helicobacter pylori Infection
Helicobacter pylori, a bacteria shown to cause peptic ulcer disease, is associated with immune stimulation. According to Robert McMillan M.D. at The Scripps Research Institute, Italian and Japanese studies report increased incidence of H. pylori infection in ITP patients. However, a U.S. study showed no increased incidence of H. pylori in ITP patients. Investigation of treatment of H. pylori infection as a treatment for ITP remains uncommon in the United States.
References
- "Blood and Circulatory Disorders Sourcebook" (Health Reference Series); Amy L. Sutton (ed); 2005
- "Women and Autoimmune Disease"; Robert G. Lahita, MD, PhD.; 2004
- National Heart, Lung and Blood Institute ITP
- Infectious Disease News: H. pylori detection, eradication effective for people with ITP
