Studies have shown that the average concentration of SAA in most RA patients is significantly higher than normal levels, and it is positively correlated with the level of inflammatory cytokines, such as ESR, CRP, IL-4, IL-6, IL-10, IL-17, rheumatoid factor (RF) and anti-cyclic citrullinated peptide antibody (ACCP)(88). Here, CRP is linked to rheumatoid arthritis.