PTPN22 and rheumatoid arthritis: Further, the 1858T allele of PTPN22 was significantly increased in RA and CD patients compared with the control group subjects (10.0% and 14.4% as opposed to 4.2%, χ2=5.35, P=0.021, OR=2.56, 95%CI=1.19–5.47 for RA and χ2=9.86, P=0.002, OR=3.87, 95%CI=1.68–8.95 for CD) (Table 3).