The function of NF-κB during infection is to regulate the transcription of hundreds of genes, including antigen receptors, inflammatory and immunoregulatory cytokines, adhesion molecules, inhibitors of apoptosis, acute phase proteins, and innate effector molecules; for this reason, it was stated that the mild or subclinical respiratory abnormalities involved in PRRSV infection might be due to the lack of activation of NF-κB. The gene discussed is NFKB1; the disease is infection.