XRCC5 and systemic lupus erythematosus: Autoantibodies against NCL and Ku70/Ku80 are characteristic features of SLE [37], [38] and release of free DNA from EMSA-bound DNA in vitro implies that autoantibodies in vivo could impair the function of these proteins by disrupting the binding of bound proteins from target DNA, including the rs13023380 locus.