We have demonstrated a significant association between elevated IRF5 expression in primary Mo of SLE patients with the IRF5-SLE H2 risk haplotype [15]; in addition, we recently showed that IRF5 is constitutively activated in Mo, and not T or natural killer (NK) cells, from SLE patients compared to healthy donors [37]. This evidence concerns the gene IRF5 and systemic lupus erythematosus.