IRF8 and systemic sclerosis: When the 23 SSc-PBC patients were analysed separately, no significant association was observed when they were compared with the 3,621 controls for any SNPs; furthermore, their addition to the whole sample (23 SSc-PBC + 1,628 SSc patients) did not modify the results (significant association for PLCL2, IRF8, and NF-κB, with unchanged magnitude of the effects).