None of the 9 SNPs with nominal P values in the range 10-5 to 5×10-7 (Table 4) map to loci previously associated with RA. Of particular interest is the association of SNPs mapping close to both the alpha and beta chains of the IL2 receptor (rs2104286 in the case of IL2RA; rs743777 and IL2RB). The IL2 receptor mediates IL2 stimulation of T lymphocytes and is thereby thought to have an important role in preventing autoimmunity. A rare 4-base-pair deletion of IL2RA has been associated with development of severe autoimmune disease90, and there is evidence (from previous data91, and from this study and its follow-up) that SNPs within the IL2RA gene region are associated with T1D (see also T1D section).
