SAA2 and rheumatoid arthritis: SAA1 and SAA2 are increased in the acute phase of inflammation by up to 1000-fold and are related to proteins involved in angiogenesis factor regulation, such as intracellular adhesion molecule 1 (ICAM-1), vascular cell adhesion molecule 1 (VCAM-1), and matrix metalloproteinase 1 (MMP1), in RA [32].