PTPN22 and autoimmune disease: In this respect, since small molecule inhibitors of Lyp would have preventative and/or therapeutic efficacy in patients with a wide range of autoimmune diseases (especially in individuals who are carriers of the PTPN22 rs2476601 (R620W) genetic variant), the lack of association between the PTPN22/CSK polymorphisms pathway and HSP indicate that small molecule inhibitors of Lyp may not have a beneficial effect in patients with this vasculitis.