SAA is an acute phase protein, mainly produced by the liver and released in response to inflammation or infections. Indeed, SAA production is stimulated by pro-inflammatory cytokines such as IL-6, IL-1 and TNF-α (Calabrò et al., 2010). SAA has a role in cholesterol metabolism as it circulates in low levels bound to High-Density Lipoprotein (HDL) (Coetzee et al., 1986). During inflammation, SAA levels strongly increase and the protein can constitute up to 80% of HDL apolipoproteins. SAA is also a precursor of amyloid A protein, an insoluble product whose pathological accumulation is named amyloidosis (Husebekk et al., 1985). Blood levels of SAA are increased in numerous inflammatory disorders including Rheumatoid Arthritis (Targonska-Stepniak and Majdan, 2014) .
Bioclinica Lab employs a manual sandwich immunoassay for the measurement of human SAA in serum.
Calabrò, P., Riegler, L., Limongelli, G., Maddaloni, V., Martone, F., Golia, E., D’Alessandro, R., Pacileo, G., Russo, M.G., Golino, P., et al. (2010). Production of Serum Amyloid a in Response to Inflammatory Cytokines by Human Adipocytes. Eur. J. Inflamm. 8, 99–105.
Coetzee, G.A., Strachan, A.F., van der Westhuyzen, D.R., Hoppe, H.C., Jeenah, M.S., and de Beer, F.C. (1986). Serum amyloid A-containing human high density lipoprotein 3. Density, size, and apolipoprotein composition. J. Biol. Chem. 261, 9644–9651.
Husebekk, A., Skogen, B., Husby, G., and Marhaug, G. (1985). Transformation of amyloid precursor SAA to protein AA and incorporation in amyloid fibrils in vivo. Scand. J. Immunol. 21, 283–287.
Targonska-Stepniak, B., and Majdan, M. (2014). Serum Amyloid A as a Marker of Persistent Inflammation and an Indicator of Cardiovascular and Renal Involvement in Patients with Rheumatoid Arthritis. Mediators Inflamm. 2014, e793628.