The association between plasma levels of acute phase proteins, haptoglobin, alpha-1 acid glycoprotein (AGP), Pig-MAP, transthyretin and serum amyloid A (SAA) in Large White and Meishan pigs

During infection, the acute phase response triggers the release of acute phase proteins (APP), alpha-1 acid glycoprotein (AGP), serum amyloid A (SAA) and Pig-MAP into the circulation, accompanied by a decrease in plasma levels of transthyretin. We quantified the association between these APP in 26 apparently healthy pigs from two breeds, 13 Large White and 13 Meishan (16 male; 10 female). There was a significant correlation between plasma levels of haptoglobin and Pig-MAP (r = 0.57; p < 0.05), but no significant associations between any of the other APP tested. We also measured the relationship between PigMAP, transthyretin and SAA, and the proportions of peripheral blood mononuclear sub-sets, CD8+ cells, CD4+ cells, CD11R1+ cells, MHC DQ+ cells, and monocytes. There were correlations between both plasma levels of Pig-MAP and the proportion of monocytes (r = 0.55; p < 0.05) and plasma levels of transthyretin and the proportion of MHC DQ+ cells (r = 0.40; p < 0.01). Breed and sex influenced plasma levels of Pig-MAP but not plasma levels of transthyretin. Overall, these results suggest closer links between the mechanisms that regulate the release haptoglobin, Pig-MAP and monocytes compared to those that regulate the release of AGP, SAA and transthyretin.