Factor VIII–related antigen, now recognized as von Willebrand factor (vWF), is a large multimeric glycoprotein synthesized predominantly by vascular endothelial cells and megakaryocytes. In endothelial cells, vWF is stored within Weibel–Palade bodies, while platelet-associated vWF is stored in platelet α-granules. In addition to its essential role in primary haemostasis and stabilization of circulating coagulation factor VIII, its highly restricted endothelial expression makes it an important marker of vascular differentiation in diagnostic immunohistochemistry.
Biological Significance
- Marker of mature endothelial differentiation and vascular integrity.
- Stored in endothelial Weibel–Palade bodies, producing a characteristic granular cytoplasmic staining pattern in IHC.
- Physiologically involved in platelet adhesion, platelet aggregation, and stabilization of coagulation factor VIII in plasma.
Diagnostic Utility in Soft Tissue Pathology
- Supports identification of vascular tumours including haemangioma, epithelioid haemangioendothelioma, and well-differentiated angiosarcoma.
- Assists in confirming endothelial lineage when interpreted alongside morphology and complementary endothelial markers such as CD31, CD34, and ERG.
- Particularly useful for highlighting well-formed vascular channels and mature endothelial cells.
- Sensitivity may be reduced in poorly differentiated or high-grade angiosarcomas, as these neoplasms often exhibit diminished endothelial differentiation and may contain few or absent Weibel–Palade bodies.
Key Features of CE/IVD Anti-Factor VIII–Related Antigen Antibodies
- Validated for clinical diagnostic immunohistochemistry on formalin-fixed, paraffin-embedded (FFPE) tissue sections.
- Typically produce strong granular cytoplasmic staining of vascular endothelial cells.
- Available in optimized ready-to-use and concentrated formats compatible with automated staining platforms.
- Suitable for applications in soft tissue pathology, vascular tumour diagnosis, and endothelial cell identification workflows.
- Intended for use as part of a multiparametric endothelial marker panel to maximize diagnostic sensitivity and specificity.
