Clinical Pathology: Hematology & Coagulation, Transfusion Medicine

• Weibel-Palade bodies are secretory organelles found in endothelial cells.

• They appear as oval or elongated organelles with a whorled or “fingerprint”-like appearance on electron microscopy.

• Weibel-Palade bodies store von Willebrand factor (vWF) and P-selectin. vWF participates in primary hemostasis by binding platelets to the subendothelium and also stabilizes factor VIII in the plasma. P-Selectin participates in leukocyte adhesion.

• Qualitative or qualitative disorders of vWF can lead to a mild to severe bleeding disorder known as von Willebrand disease.

• Other proteins contained in Weibel-Palade bodies include interleukin-8, endothelin, and tissue plasminogen activator.

• Desmopressin-induced increase in vWF is most likely due to the direct release of multimeric vWF from Weibel Palade bodies.

Valentijn KM, Sadler JE, Valentijn JA, et al: Functional architecture of Weibel-Palade bodies. Blood. 2011;117:5033–5043.

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