Autoimmune-associated PTPN22 R620W variation reduces phosphorylation of lymphoid phosphatase on an inhibitory tyrosine residue. by Fiorillo, E, Orrú, V, Stanford, S, Liu, Y, Salek, M, Rapini, N, Schenone, A, Saccucci, P, Delogu, L, Angelini, F, Manca Bitti, M, Schmedt, C, Chan, A, Acuto, O, Bottini, N