Studying extracellular vesicles in immune thrombocytopenia

Primary Immune Thrombocytopenia (ITP) is an acquired isolated trombocytopenia
(platelet count < 100 x 109/l) without an underlying disease or cause of the
thrombocytopenia. ITP can occur due to increased platelet clearance medicated
by autoantibodies, decreased platelet production and T-cell mediated processes.
The incidence of ITP is approximately 50/1.000.000. The prevalence is equally
distributed between male and female, except for the age category 30-60 years
where the prevalence of ITP is higher in female. ITP is classified according
the duration of the disease: acute ITP, persistent ITP (3-12 months) and
chronic ITP (>12 months). Most important symptoms are bleeding and decreased
health related quality of life. Clinical symptoms may vary between none to life
threatening bleedings. Most bleeding symptoms occur with a platelet count
<30x109/L although there is no relationship between platelet count and bleeding
severity.

Due to the large heterogeneity between patients it is difficult to predict
disease severity and therapy response. A better understanding of the underlying
pathology is most important to improve patient care.
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Recent data shows that patients with ITP have increased levels of the so called
platelet-extracellular-vesicles (EVs). In this pilotstudy we would like to
characterize these EVs and investigate whether they play a pathogenic role in
the maintenance of ITP. Also we would like to measure the association with
therapy response.

single center observational pilotstudy. Test will be performed at Sanquin
Amsterdam and patients will be recruited at Erasmus MC.

The burden for ITP patients is one blood draw during routine clinical test. The
amount of blood is 9mL in total (One 3mL EDTA tube and two 3mL citrate tubes).