Diagnostic Role of Antiphospholipid Antibodies and Microparticles in Immune Thrombocytopenic Patients With Thrombosis

Study Overview
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Brief Summary
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Identify the procoagulant profile in immune thrombocytopenic patients with thrombosis. Clinical implications of antiphospholipid antibodies in ITP patients with thrombosis. Diagnostic role of microparticles in ITP patients with thrombosis.

Detailed Description
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Immune thrombocytopenia (ITP) is an acquired autoimmune disorder characterized by isolated thrombocytopenia and an increased risk of bleeding. Paradoxically, ITP is also associated with an increased risk of thrombosis (1). Recent studies showed that the occurrence of thrombosis in patients with ITP is not purely accidental and can be considered a clinical reality with an important impact on the management of the disease (2). The pathophysiological mechanism for thrombosis in ITP remains unclear. Sever bleeding episodes are relatively rare in some patients with ITP although having low platelet count, suggests that these patients may have a protective factor against bleeding (3). Antiphospholipid (aPL) antibodies are a heterogeneous group of autoantibodies with high affinity for phospholipids such lupus anticoagulant (LA), β2glycoprotien І (β2GPІ), and anticardiolipin (anti-CL). They interfere with physiological mechanisms of coagulation and fibrinolysis, leading the haemostatic balance towards coagulation. Moreover, it seems to affect the physiological function of various cells such as platelets and endothelial cells (4). Microparticles (MPs) are a diverse group of bioactive small-sized vesicles (100-1000nm) that can be found in body fluids and blood after activation, necrosis, or apoptosis of almost all cells. Although most MPs in human blood originate from platelets, MPs are also released from leukocytes, erythrocytes, endothelial cells, smooth muscle cells and cancer cells (5). They participate in intercellular communication and play a major role in homeostasis under physiological conditions and also in diseases (6). The most prominent property of MPs is their procoagulant potential, mainly based on phosphatidylserine exposure and tissue factor expression (7). Elevated levels of antiphospholipid antibodies and microparticles have been reported as a risk for development of prothrombotic state (8).

Official Title
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Diagnostic Role of Antiphospholipid Antibodies and Microparticles in Immune Thrombocytopenic Patients With Thrombosis

Conditions
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Thrombosis

Intervention / Treatment
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* Diagnostic Test: Antiphospholipid antibodies


Participation Criteria
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Eligibility Criteria
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Patients with confirmed diagnosis of primary chronic ITP with and without thrombosis, male or female above age of 18.Inclusion Criteria: Exclusion Criteria: Thrombocytopenic patients due to secondary causes such as pregnant women, patients with uncontrolled hypertension, peripheral or coronary artery disease, abnormal hepatic or renal function tests, bleeding disorder, and thrombopathy well be excluded from the study. Patients full fill the criteria of antiphospholipid syndrome (APS).

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 70 Years

Sexes Eligible for Study
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All

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| ITP with thrombosis<br>History taking including any medical history, family history, drug intake, arterial or venous thrombotic events. Venous blood samples will be collected by vein puncture under aseptic precautions for: Routine laboratory investigations: Complete blood picture with assessment of platelet count. Coagulation tests including prothrombin time (PT), activated partial thromboplastin time (APTT), fibrinogen and D-dimer. Liver and Kidney functions test. Specific laboratory investigations: Antiphospholipid antibodies assay which includes: Lupus anticoagulant (LA) by diluted Russel viper venom method. Anti β2glycoprotien І (β2GPІ), by enzyme-linked immunosorbent assay (ELISA). Anticardiolipin by (ELISA). Detection of Microparticles and their subtypes by flow cytometry: Annexin-v for all microparticles. CD 41 for platelet microparticles. CD 146 for endothelial microparticles. | Diagnostic Test: Antiphospholipid antibodies<br>* Antiphospholipid (aPL) antibodies are a heterogeneous group of autoantibodies with high affinity for phospholipids such lupus anticoagulant (LA), β2glycoprotien І (β2GPІ), and anticardiolipin (anti-CL). They interfere with physiological mechanisms of coagulation and fibrinolysis, leading the haemostatic balance towards coagulation. Moreover, it seems to affect the physiological function of various cells such as platelets and endothelial cells<br>|
| ITP without thrombosis<br>History taking including any medical history, family history, drug intake, arterial or venous thrombotic events. Venous blood samples will be collected by vein puncture under aseptic precautions for: Routine laboratory investigations: Complete blood picture with assessment of platelet count. Coagulation tests including prothrombin time (PT), activated partial thromboplastin time (APTT), fibrinogen and D-dimer. Liver and Kidney functions test. B- Specific laboratory investigations: Antiphospholipid antibodies assay which includes: Lupus anticoagulant (LA) by diluted Russel viper venom method. Anti β2glycoprotien І (β2GPІ), by enzyme-linked immunosorbent assay (ELISA). Anticardiolipin by (ELISA). Detection of Microparticles and their subtypes by flow cytometry: Annexin-v for all microparticles. CD 41 for platelet microparticles. CD 146 for endothelial microparticles. | Diagnostic Test: Antiphospholipid antibodies<br>* Antiphospholipid (aPL) antibodies are a heterogeneous group of autoantibodies with high affinity for phospholipids such lupus anticoagulant (LA), β2glycoprotien І (β2GPІ), and anticardiolipin (anti-CL). They interfere with physiological mechanisms of coagulation and fibrinolysis, leading the haemostatic balance towards coagulation. Moreover, it seems to affect the physiological function of various cells such as platelets and endothelial cells<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Identify the procoagulant profile in immune thrombocytopenic patients with thrombosis. | Clinical implications of antiphospholipid antibodies in ITP patients with thrombosis. Diagnostic role of microparticles in ITP patients with thrombosis. | 2 years |