IRF5 and viral infectious disease: The Genome-Wide Association studies (GWS) reported a strong association in SS within the HLA region at 6p21 (OR = 3.5) and with IRF5 (transcription factor mediating type I interferon responses in monocytes, dendritic cells, and B cells that induces the transcription of interferon-alfa genes and the production of pro-inflammatory cytokines upon viral infection), STAT4, IL12A and TNIP1 loci [9]; although genetic factors determine the baseline disease susceptibility and disease phenotype, these factors contribute modestly to the clinical condition [10].