Abstract Number: PB0822
Meeting: ISTH 2021 Congress
Theme: Platelet Disorders, von Willebrand Disease and Thrombotic Microangiopathies » Acquired Thrombocytopenias
Background: Immune thrombocytopenia (ITP) is associated with a heterogeneous clinical presentation, which cannot be predicted by the platelet count. Platelet activation might influence the clinical presentation of ITP.
Aims: To investigate platelet activation in a cohort of 51 adult patients with primary ITP and 18 age- and sex-matched non-immunological thrombocytopenic controls (TPC).
Methods: Patients were included in two haematological centers after written informed consent (EC1843/2016). Soluble P-selectin (sPsel) levels and platelet function by flow cytometry, uninitiated and after addition of agonists were assessed.
Results: Patient characteristics are shown in Table 1. All analyses were adjusted for platelet counts. Median sPsel levels [25-75 percentile] and non-activated CD62P were increased in ITP compared to TPC (sPsel 31.7 [23.3-52.2] and 14.5 [5.1-23.9], p=0.002; CD62P 0.0 [0.0-9.5] and 0.0 [0.0-0.0], p=0.044; Figure 1). ITP patients under treatment had higher sPsel-levels than untreated patients (44.3 [30.7-61.2] and 28.2 [19.6-47.5], p=0.013), whereas there was no difference in other parameters of platelet function. TPO-RA-treated patients had higher median sPsel and lower PAC-1 ADP than untreated patients (sPsel 60.5 [33.8-70.0] and 27.3 [17.3-47.2], p=0.019; PAC-1 ADP 40.8 [18.1-75.7] and 157.6 [63.9-267.5], p=0.017), while there was no difference in comparison to corticosteroid-treated patients (sPsel 38.6 [24.8- 60.9], p=0.181 and PAC1-ADP 90.7 [23.1-366.1], p=0.784). Splenectomized patients tended towards higher sPsel-levels compared to non-splenectomized (46.4 [30.4-70.6] and 30.6 [17.6- 50.4], p=0.056). Previous thrombosis had no impact on sPsel-levels or platelet activation markers. Bleeding severity, assessed by the ISTH-ITP-BAT showed a weak correlation with unactivated CD62P (ß=0.34, p=0.016), whereas there was no correlation with sPsel or other parameters of platelet activity.
ITP | TPC | |||||
n | n1 | % | n | n1 | % | |
Gender, female | 51 | 35 | 68.6 | 18 | 9 | 50 |
Current ITP treatment |
51
|
18
|
na
|
na
|
||
none | 33 | 64.7 | ||||
Corticosteroids | 6 | 11.8 | ||||
TPO-RA | 9 | 17.7 | ||||
others | 3 | 5.9 | ||||
Previous thrombosis | 50 | 4 | 8 | 18 | 3 | 16.7 |
Splenectomy | 50 | 12 | 24 | 18 | 0 | 0 |
n |
median |
25-75 percentile |
n |
median |
25-75 percentile |
|
Age, years | 51 | 47 | 32-55 | 18 | 59 | 46-62 |
Platelet count, x10⁹/L | 51 | 77 | 41-139 | 18 | 60 | 21-76 |
Duration of disease, months | 51 | 113 | 40-162 | 18 | na | na |
BS SMOG-Index, total | 51 | 2 | 0-6 | 18 | 2 | 1-4 |
Patients´ clinical and laboratory characteristicsComparison of sP-selectin (ng/ml) and unactivated CD62P MFI (median fluorescence intensity) between ITP patients and non-immunological thrombocytopenic controls (TPC)
Conclusions: ITP-patients have increased sPsel, especially under TPO-RA-treatment, whereas there was no clear pattern of platelet hyperreactivity. There was no association or correlation of platelet activation markers with previous thrombosis or bleeding severity.
To cite this abstract in AMA style:
Machacek J, Buresch L, Mehic D, Schramm T, Fillitz M, Dixer B, Flasch T, Anderle T, Rath A, Ay C, Pabinger I, Gebhart J. Platelet Activation and Function in Adult Patients with Primary Immune Thrombocytopenia [abstract]. Res Pract Thromb Haemost. 2021; 5 (Suppl 2). https://abstracts.isth.org/abstract/platelet-activation-and-function-in-adult-patients-with-primary-immune-thrombocytopenia/. Accessed December 6, 2023.« Back to ISTH 2021 Congress
ISTH Congress Abstracts - https://abstracts.isth.org/abstract/platelet-activation-and-function-in-adult-patients-with-primary-immune-thrombocytopenia/