PTPN22 and Behcet disease: In line with that, although the genetic influence of PTPN22/CSK in several vasculitides (such as giant cell arteritis, Behçet’s disease and antineutrophil cytoplasmic antibody (ANCA)-associated vasculitides [12–14]) has been demonstrated, there is scarce information on the role of PTPN22/CSK in HSP.