Overview of Adult Immune Thrombocytopenia

Leonard I. Boral*, Gregory P. Monohan and Valentina Moirangthem

Overview of Adult Immune Thrombocytopenia.

There have been somewhat divergent criteria for making the diagnosis of immune thrombocytopenia. However, an attempt to standardize the definition of ITP has been made with the publication by the International Work Group on ITP in 2009.

Despite this attempt to standardize those descriptions, many physicians do not conform to these definitions, so confusion in terminology persists. After publication of the IWG guideline, most use immune thrombocytopenia.

Its various other names have included “idiopathic thrombocytopenic purpura”, “autoimmune thrombocytopenic purpura”, “immune thrombocytopenic purpura”, “autoimmune thrombocytopenia”, and “primary thrombocytopenic purpura”. Despite what it is called, it represents an acquired autoimmune process and is no longer considered idiopathic.

Autoantibodies are not only directed against the patient’s own platelets, leading to their destruction by
the spleen, but there may be humoral autoimmune processes involving the platelet progenitor,
the megakaryocyte, resulting in decreased platelet production.

In the 1st issue of Blood, published in 1946, Damasheck and Miller reviewed the megakaryocyte counts and bone marrow morphology of patients with idiopathic thrombocytopenia and demonstrated most had an increase in the megakaryocyte count, however few platelets were produced.

Multiple Fc receptor pathways are involved in the humoral immune response associated with ITP. It has also been discovered that cellular autoimmune disruption contributes to thrombocytopenia in ITP.

The IWG also says that in order to call ITP refractory, the patient should have failed splenectomy and have a risk of bleeding that requires treatment. Since the risk of bleeding and hemorrhagic fatality rate increases with advanced age (greater
than 45 years old) treatment options should take into consideration the age of the patient.

Pathol Lab Med Open J. 2016; 1(1): 21-31. doi: 10.17140/PLMOJ-1-105