CRP and rheumatoid arthritis: The most frequently used acute-phase proteins as RA biomarkers are erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), serum amyloid A protein (SAA), alpha-1-acid glycoprotein (AGP or ORM), haptoglobin (HP), and alpha-1-antitrypsin (AAT) [42, 43].