This website contains promotional content and is intended for Healthcare Professionals

  1. Article
  2. Source: Campus Sanofi
  3. 21 Jul 2025

What is ITP?

Author: Sanofi

Editorial Team

     
Home
What is ITP?
Living with ITP
Future of ITP

ITP is characterized by low platelet counts and symptoms like bleeding and bruising1

ITP is an acquired autoimmune disorder characterized by low platelet counts that result from both increased platelet destruction and/or impaired platelet production.2-4

The time since diagnosis helps classify ITP as newly diagnosed, persistent, or chronic.5

Multiple symptoms of ITP are related to bleeding and can include6-10:

Petechiae and purpura, usually on the extremities

Bleeding blisters and epistaxis

Organ bleeding (eg, menorrhagia)

Intracranial haemorrhage

In some studies, severe bleeding occurred in approximately 7% to 10% of adult patients and typically correlated with lower platelet counts.11,12*

*As seen in a cross-sectional study of 302 French patients, as well as in a systematic review of 147 clinical studies of adults and children with primary ITP.11,12

While platelet counts below 100,000/μL can indicate ITP, the lack of a specific diagnostic test means other potential causes of thrombocytopenia must be ruled out.2

It is also important to determine if ITP is primary or secondary to another condition. There are multiple causes of secondary ITP, including chronic lymphocytic leukemia (CLL), Helicobacter pylori infection, and COVID-19 infection.2,14

ITP can occur in people of all ages. The incidence of ITP ranges from 2 to 4 cases per 100,000 person-years in adults and children.2,15

The prevalence of ITP is estimated to be 58 per 100,000 adults and between 4.1 and 9.3 per 100,000 children (ages 1 to 18 years).16,17

The pathophysiology of ITP is complex and not fully understood2

In ITP, autoreactive B cells produce autoantibodies that target platelets for destruction by macrophages and impair megakaryocyte maturation, which then inhibits platelet production. Autoantibodies may also destroy platelets through other mechanisms. Cytotoxic T cells can also directly destroy or inhibit the production of platelets.2

Watch the mechanism of disease video to learn more about the underlying sources of ITP

Bruton’s tyrosine kinase (BTK) drives key processes in B cells and macrophages19,20

B cells are critical to autoantibody production and macrophages are critical to phagocytosis. Both of these processes are regulated by BTK.

  • In B cells: The BTK pathway is crucial for proliferation, differentiation, and autoantibody production
  • In macrophages: Various signaling pathways dependent on BTK drive phagocytosis, degranulation, and the production of inflammatory cytokines

BTK is also a critical driver of inflammation20

BTK plays a key role in the production or activation of these inflammatory markers:

  • TNF-α
  • IL-6
  • NLRP3 inflammasome
  • IFN-γ

Next: ITP is about more than platelets

Learn how ITP symptoms like fatigue and cognitive impairment impact patients’ quality of life.

Living with ITP

MAT-BH-2500351-V1-July-25  

Related