Platelet function in adult ITP patients can be either increased or decreased, compared to healthy controls, and is associated with bleeding risk

Abstract

Objectives: To test whether, together with platelet count, platelet activity could be an important predictor of bleeding risk in immune thrombocytopenia (ITP) patients.Methods: Platelet activity was tested by flow cytometric measurement of agonist induced P-selectin expression and compared between 23 adult ITP patients and 22 healthy volunteers. Results: Platelet activity could be either increased or decreased in ITP patients, compared to healthy volunteers. In the lowest platelet count category, normal to low platelet activity was associated with the biggest increase in bleeding risk. Risk difference 80% (95% confidence interval: 45-115%) for <32 × 10 9 platelets/L. For higher platelet counts, there was no association of platelet activity with bleeding risk. Discussion: Increased platelet activity was associated with decreased bleeding risk, but only in patients with low platelet counts. Conclusion: Platelet activity can be a predictor of bleeding risk in ITP patients with low platelet counts.

Cardiovascular and bleeding outcomes in a population‐based cohort of patients with chronic immune thrombocytopenia

“…It is reasonable that patients suffering from active bleeding have lower levels of thrombocytes, and functionally different thrombocytes, than patients without bleeding. This inference is supported by a recent study of cITP patients indicating that prediction of bleeding events could be improved by measuring platelet reactivity, particularly in patients with low platelet counts . Our analyses showed that low platelet count was a strong risk factor for bleeding, however; even patients with moderate and mild thrombocytopenia could experience a bleeding event.…”

Phase 2 study of efgartigimod, a novel FcRn antagonist, in adult patients with primary immune thrombocytopenia

“…19 Moreover, they can inhibit megakaryocyte proliferation and differentiation resulting in diminished platelet production. 24 The majority of antiplatelet antibodies is directed against GPIIb/IIIa and GPIb/IX, 25,26 but additional targets have been identified. 24 The majority of antiplatelet antibodies is directed against GPIIb/IIIa and GPIb/IX, 25,26 but additional targets have been identified.…”

“…[20][21][22] Recently, it has been reported that some anti-GP antibodies interfere with platelet functionality, inhibiting platelet aggregation 23 and blood clot formation. 24 The majority of antiplatelet antibodies is directed against GPIIb/IIIa and GPIb/IX, 25,26 but additional targets have been identified. 14 The central role of autoantibodies in the pathogenesis is further illustrated by occurrence of ITP in infants born to mothers with ITP, due to placental transfer of autoantibodies, 27 and by historical use of IgG-depleting treatments like immunoadsorption and plasmapheresis, which lead to a reduction of platelet-associated autoantibodies 28 and increased platelet count.…”

The association between idiopathic thrombocytopenic purpura and cardiovascular disease: a retrospective cohort study

“…Idiopathic thrombocytopenic purpura (ITP) is an acquired immune‐mediated disease defined as a transient or persistent decrease of platelet count . The decreased platelet count in ITP is associated with an increased rate of bleeding, hemorrhage‐related outcomes and abnormal platelet activity . The global incidence rate for ITP in adults is estimated to be 1.6–3.9/100 000 persons with incidence rates estimated at 5.6–20/100 000 population .…”