Thrombosis in patients with primary chronic immune thrombocytopenia
Section snippets
Immune thrombocytopenia
Primary immune thrombocytopenia (ITP) is an autoimmune hematological disorder characterized by low platelet count due to immune-mediated platelet destruction and/or suppressed platelet production [1], [2]. Persistence of thrombocytopenia for at least 12 months following ITP diagnosis is classified as chronic ITP [3]. In adults, ITP most often is a chronic disease with insidious onset [4]. The clinical presentations of ITP is symptomatic bleeding but may vary considerably from no bleeding
Platelet function in patients with chronic ITP
Two immune-mediated mechanisms play a role in the pathogenesis of chronic ITP: increased platelet destruction and decreased platelet production [2]. In a seminal study from 1951, Harrington provided the first evidence that thrombocytopenia in ITP is caused by a plasma-derived factor [8], later identified as an antiplatelet antibody [9]. These autoantibodies are often directed against epitopes of glycoprotein (GP) IIb/IIIa or GP Ib/IX although ITP patients may have antibodies directed against
Risk of Venous Thromboembolism (VTE)
Despite the presence of thrombocytopenia VTE has been reported to occur in patients with chronic ITP [15], [16]. Actually, ITP patients may paradoxically have an increased risk of VTE. This could be a consequence of more thrombotically active platelets or because of increased prevalence of known risk factors for VTE in patients with chronic ITP. Patients with chronic ITP may have a high prevalence of antiphospholipid antibodies or lupus anticoagulans [17], [18]. Chronic ITP patients also have
Conclusion
In conclusion, despite increased risk of bleedings patients with primary chronic ITP also have a higher risk of VTEs than the background population. VTEs can occur in patients with chronic ITP even in the presence of low platelet count and in the absence of antiphospholipid antibodies. Therefore, clinicians should keep this potential diagnosis in mind in patients with chronic ITP.
Conflicts of interest statement
The author did not report employment, consultancies, stock ownership, honoraria, paid expert testimony, grants, or consultancies that could inappropriately influence this manuscript. The Department of Clinical Epidemiology, Aarhus University Hospital Denmark is involved in studies with funding from various pharmaceutical companies as research grants to (and administered by) Aarhus University, Denmark.
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