Immune Thrombocytopenic Purpura (ITP), sometimes referred to as Idiopathic Thrombocytopenic Purpura, occurs when your body’s immune system destroys its own platelets, in the same way it would destroy harmful invaders such as bacteria. Platelets are important for helping the blood to clot and stop bleeding.
Usually when foreign invaders (pathogens) are detected by the immune system, the body makes antibodies which then coat the bacteria, marking them for destruction. In ITP, the body mistakenly produces antibodies against its own platelets. In ITP, the immune system has lost some of its ability to distinguish between foreign substances and the body’s own cells. The antibody-coated platelets are destroyed by specialized cells called macrophages, which exist in large numbers in the spleen.
In some patients, the low platelet counts seen in ITP may be due to impaired platelet production that may occur along with antibody-mediated destruction of platelets1,2
- Ballem P.J., Segal G.M., Stratton J.R., Gernsheimer T, Adamson JW, Slichter SJ. Mechanisms of thrombocytopenia in chronic autoimmune thrombocytopenic purpura. Evidence of both impaired platelet production and increased platelet clearance. J Clin Invest. 1987;80:33-40.
- Cines D.B., Blanchette V.S. Immune Thrombocytopenic Purpura. New England Journal of Medicine. 2002; 346(13): 995-1008.
