Non-Malignant Hematology

Immune Thrombocytopenia (ITP): An Autoimmune Disease With Potentially Serious Consequences

Outline

  • Overview of immune thrombocytopenia
  • Burden of disease
  • Normal physiology
  • Pathophysiology
  • Treatment considerations and strategies

Immune Thrombocytopenia Is an Autoimmune Disorder That Results in Decreased Platelet Counts

  • Immune thrombocytopenia (ITP) is characterized by a persistent or chronic decrease of platelet counts (<100 x 109/L) and an increased risk of bleeding1
  • Physical examination reveals only evidence of platelet-type bleeding (petechiae, purpura, conjunctival hemorrhage or other types of cutaneous bleeding)2
  1. Rodeghiero F, et al. Blood. 2009;113:2386-2393.
  2. Cines DB, Blanchette VS. N Engl J Med. 2002;346:995-1008.

Normal Physiology: Thrombopoietin Is the Primary Driver of Platelet Production

  • Thrombopoietin (TPO) is the endogenous cytokine for megakaryocyte growth and platelet delivery to circulation
  • TPO is produced continuously in the liver and binds specifically to the TPO receptor (TPO-R) found on platelets, megakaryocytes, and other hematopoietic cells

BFU-MK, burst-forming unit-megakaryocyte; CFU-MK, colony-forming unit-megakaryocyte. Adapted from: Prow D, Vadhan-Raj S. Oncology 1998;12:1597-1614.
Deutsch VR, Tomer A. Br J Haematol. 2006;134:453-466.

Thrombopoietin drives platelet production

ITP Pathophysiology: Accelerated Platelet Destruction1,2

Autoantibodies bind to healthy platelets, resulting in their sequestration and destruction in the spleen. TPO clearance increases in parallel with platelet destruction.

  1. Cines DB, Blanchette VS. N Engl J Med. 2002;346:995-1008.
  2. Houwerzijl EJ. Blood. 2004;103:500-506.
Autoantibodies bind to healthy platelets