However, unlike human IRF5 that exists as multiple alternatively spliced variants [19], murine IRF5 appears to exist as a single major variant [28], suggesting inherent complexities between studies of IRF5 in human SLE and murine lupus-like disease; nevertheless, current data support a critical role for IRF5 in both human and murine SLE pathogenesis. Here, IRF5 is linked to systemic lupus erythematosus.