Despite the inhibitory control actions on pDC, an IFN-α response to PCV2 infection has been repeatedly detected in vivo; after the IFN-α response, elevated levels of serum C-Reactive Protein and IL-10 in the secondweek after infection were associated with PCV2-infected piglets that subsequently developed severe PMWS [189]; additionally, a clear correlation was observed between viral load and IL-10 amounts in vivo [190]. This evidence concerns the gene IFNA2 and infection.