Immune thrombocytopenia is a disorder characterized by a blood abnormality called thrombocytopenia, which is a shortage of blood cells called platelets that are needed for normal blood clotting.

The genetic cause of immune thrombocytopenia is unclear. This condition occurs when the body's own immune system malfunctions and attacks the body's tissues and organs (autoimmunity). Normally, the immune system produces proteins called antibodies, which attach to specific foreign particles and germs, marking them for destruction. In immune thrombocytopenia, the immune system abnormally destroys platelets and makes fewer platelets than normal. People with immune thrombocytopenia produce antibodies that attack normal platelets. The platelets are destroyed and eliminated from the body, resulting in a shortage of these cells in affected individuals. Some of these antibodies also affect the cells in the bone marrow that produce platelets (known as megakaryocytes), which leads to a decrease in platelet production, further reducing the number of platelets in the blood.

The incidence of immune thrombocytopenia is approximately 4 per 100,000 children and 3 per 100,000 adults. In adults with immune thrombocytopenia, women are affected more often than men.

Immune thrombocytopenia and other autoimmune disorders can run in families, but the inheritance pattern is usually unknown. People with a first-degree relative (such as a parent or sibling) with immune thrombocytopenia likely have an increased risk of developing the disorder themselves.

Published Date: June 01, 2017Published By: National Institutes of Health