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Sunitinib-associated pseudothrombocytopenia induced by IgM antibody
Arjan Albersen1, Leendert Porcelijn, Joyce Schilders
1Department of Clinical Chemistry and Hematology, Sint Franciscus Gasthuis , Rotterdam , The Netherlands.
Platelets
|October 17, 2012
Summary
Sunitinib treatment can cause pseudothrombocytopenia (PTCP), a condition where platelets clump in blood samples, mimicking low platelet counts. This case highlights the importance of recognizing PTCP to avoid unnecessary treatments.
Area of Science:
- Hematology
- Oncology
- Clinical Pathology
Background:
- Thrombocytopenia is a known adverse effect of sunitinib, a tyrosine kinase inhibitor used in cancer therapy.
- Accurate platelet count is crucial for patient management and treatment decisions.
Observation:
- A patient with metastatic renal clear-cell carcinoma developed apparent thrombocytopenia during sunitinib treatment.
- Initial low platelet counts in EDTA and citrate samples suggested true thrombocytopenia, leading to platelet transfusions.
- Further investigation revealed pseudothrombocytopenia (PTCP) due to temperature- and multi-anticoagulant-dependent IgM antiplatelet autoantibodies.
Findings:
- The autoantibodies caused significant platelet clumping in citrate, followed by EDTA and heparin samples.
- Antibody specificity was directed against platelet antigens other than common GPIIb/IIIa, GPIb/IX, GPIa/IIa, GPIV, and GPV.
- PTCP resolved, and antiplatelet antibodies disappeared 16 days after discontinuing sunitinib, indicating a drug-dependent mechanism.
Implications:
- This is the first reported case of sunitinib-induced PTCP.
- Failure to recognize PTCP can lead to misdiagnosis, unnecessary platelet transfusions, and inappropriate dose adjustments or discontinuation of sunitinib.
- Awareness of drug-induced PTCP is essential for correct diagnosis and patient management in oncology settings.
