In the present study, IL-6 and IL-10 mRNA expressions were increased via PCV2b infection in NPTr and iPAM 3D4/21 cells in accordance with previous studies reporting up-regulation of IL-6 in epithelial cells [63] and increased levels of IL-6 and IL-10 in porcine alveolar macrophages (PAMs) [64,65]. Here, IL10 is linked to infection.