PTPN22 and rheumatoid arthritis: This finding is in keeping with our results, supporting that these genetic variants may play an important role in the regulatory region of PTPN22. Based on our data, we feel that the decreased PTPN22 expression in patients carrying the risk alleles of PTPN22 rs2488457 and rs2476601 may lead to a pro-inflammatory status in RA, since T cells activation would not be inhibited by this gene.