VWF and myeloid sarcoma: This shortened APTT can be mechanistically attributed to elevated Factor VIII activity secondary to increased von Willebrand factor levels, and both serve as established biomarkers of endothelial dysfunction and inflammation (Lelas et al., 2021; Mina et al., 2010; Radišić Biljak et al., 2024), indicating the vascular and inflammatory pathology in MS.