PRTN3 and granulomatosis with polyangiitis: Nevertheless, knowing the increased mobility of Epitope 3 of iHm5-Val103 responsible for its binding to moANCA518 alone may have implications for the development of novel, effective treatments of GPA that aim to disrupt the pathogenic autoantibody·autoantigen interactions in GPA by reducing the mobility of epitopes targeted by PR3-ANCAs.