Considering that CD163 and CD169 expression can be induced by IL-10 and IFN-γ respectively, and that IL-10 treatment increases PRRSV infectivity while IFN-γ decreases it [54, 56, 57], the role of these cytokine in the modulation of macrophage susceptibility to infection requires further investigation. The gene discussed is SIGLEC1; the disease is infection.