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Understanding the Disease

Chronic ITP

Understanding the Disease

What is chronic immune thrombocytopenia?

Immune thrombocytopenia (ITP) is a condition in which your body does not have enough blood cell fragments (called platelets) in the blood. For many, ITP resolves on its own. When ITP has continued for 6 months or longer, it is considered chronic. It is a rare disorder that affects 9.5 of every 100,000 Americans, both physically and emotionally.


Learn more about the signs and symptoms of ITP here


Other conditions may have similar symptoms, so it is important to be evaluated by a health care provider.

What are platelets and why are they important?

How blood clots

Platelets are cells that are made in the bone marrow and circulate in the blood.

Platelets stick together to help form blood clots. Blood clots help prevent bleeding and bruising when you get a cut or wound. When you have chronic ITP, there are not enough platelets, and blood clots do not form properly. When your platelet count is low, you may have bruising and/or bleeding that is hard to stop.

What makes your platelet count low?

In chronic ITP, the way your body controls the number of platelets in circulation is out of balance. There are 3 causes of low platelet counts:


  1. Platelets are destroyed. Your immune system thinks platelets are cells that will hurt the body, so it attacks them.
  2. Platelets are trapped in the spleen. The spleen is an organ that removes old and damaged platelets and red blood cells from blood circulation. Platelets that are attacked by the immune system are removed from the blood and trapped in the spleen.
  3. Fewer platelets are made. When you have chronic ITP, there usually is not enough thrombopoietin (TPO) reaching the bone marrow. TPO is a protein produced primarily in the liver that controls how many platelets are made. This means that there are not enough platelets being made to replace destroyed platelets.
How platelets circulate How platelets circulate

The goal of chronic ITP treatment is to help increase platelet counts to target levels.

A number of treatment options are available to help raise platelet counts in patients with chronic ITP.




Immunosuppressants are agents that slow down the immune system. Medications like corticosteroids and intravenous immunoglobulin (IVIG) are immunosuppressants that decrease the number of platelets being destroyed.


TPOr agonists


TPO-receptor agonists (also known as platelet growth factors)

Thrombopoietin receptor agonists, or TPO-receptor agonists for short, are medicines that work by sending signals to the body to make more platelets.





Splenectomy is the surgical removal of the spleen. In chronic ITP, platelets are removed from the blood and trapped in the spleen. By removing the spleen, more platelets remain in the blood circulation.