No association was found between C1858T polymorphism and diabetes-related autoimmunity (p = 0.173) or thyroid autoimmune disease (p = 0.321), respectively.
The R620W polymorphism of the PTPN22 gene is not a major risk allele for SLE susceptibility in our sample of Caucasian individuals from northern America, the UK, or Finland, but it appears to be a risk factor for the concurrent autoimmune diseases of autoimmune thyroid disease and SLE.