Multiplex family–based study in systemic lupus erythematosus: association between the R620W polymorphism of PTPN22 and the FcγRIIa (CD32A) R131 allele. - Balada, E.; Villarreal-Tolchinsky, J.; Ordi-Ros, J.; Labrador, M.; Serrano-Acedo, S.; Martinez-Lostao, L.; Vilardell-Tarrés, M. (Tissue Antigens, 2006)