As these associations have yet to be investigated in human SLE, we sought to determine if IFIH1, the human ortholog of Mda5, is associated with altered soluble mediators and autoantibodies in SLE patients compared to unaffected first-degree relatives of SLE patients (FDRs) and unrelated, unaffected controls with no family history of SLE. Here, IFIH1 is linked to systemic lupus erythematosus.