VTN and microtia: suPAR also facilitates the migration and infiltration of leucocytes,19,45 partly through its complex interactions with the adhesive glycoprotein vitronectin and adhesion receptors of the integrin family (e.g. β1 and β2 integrins),9,48 as well as through its intrinsic chemotactic properties mediated by the chemotactically active SRSRY motif.7,11 These complex interrelated immunological properties of suPAR propose a pathogenic involvement of elevated suPAR levels in MA pathophysiology.