As next, we compared proteins related to PRRSV infection that were identified in additional studies (Table 3) ; interestingly, all the 9 peaks found by [28] , and in particular the only up-regulated in PRRSV infected (corresponding to the Alpha 1 S (a1S)-subunit of porcine Haptoglobin), showed minimal MW differences (≤0.3 kDa) with up-regulated peaks identified in this study (Table 3) .