The serum amyloid A (SAA) proteins comprise a family of vertebrate amphipathic alpha-helical apolipoproteins that associate predominantly with high density lipoproteins (HDL) [1,2]. They play a role in the mobilisation of cholesterol for tissue repair and regeneration [3]. The synthesis of these proteins is greatly increased (as much as a 1000 fold) in inflammation, being a major acute phase reactant together with C-reactive protein. They act as cytokine-like proteins that are involved in cell-cell communication and in inflammatory, immunologic, neoplastic and protective pathways [4]. Prolonged elevation of plasma SAA levels, as in chronic inflammation, results in a pathological condition, called amyloidosis, which is characterised by the highly insoluble accumulation of SAA in several tissues. During chronic inflammation, SAA association with HDL can change its protein and lipid composition which abrogates the HDL anti-atherogenic properties, contributing to a pro-atherogenic state [3,4].

1: Serum amyloid A (SAA): an acute phase protein and apolipoprotein. Malle E, Steinmetz A, Raynes JG; Atherosclerosis. 1993;102:131-146. PMID:7504491

2: Evolution of the serum amyloid A (SAA) protein superfamily. Uhlar CM, Burgess CJ, Sharp PM, Whitehead AS; Genomics. 1994;19:228-235. PMID:8188253

3: Serum amyloid A levels are associated with polymorphic variants in the serum amyloid A 1 and 2 genes. Griffiths K, Maxwell AP, McCarter RV, Nicol P, Hogg RE, Harbinson M, McKay GJ; Ir J Med Sci. 2019;188:1175-1183. PMID:30852808

4: Serum amyloid A - a review. Sack GH Jr; Mol Med. 2018;24:46. PMID:30165816