Clinical value of serum amyloid A and C-reactive protein measurements in secondary amyloidosis.

Serum amyloid A protein (SAA) and C-reactive protein (CRP) are acute-phase reactants synthesized by the liver. A close relationship was found between SAA and CRP concentrations in various rheumatic diseases (rs = 0.74 to 0.83). The serum concentration of these proteins reflected the activity of the rheumatic inflammation in a sensitive way. In secondary amyloidosis, persistently high SAA and CRP levels correlated closely with the progression of the renal amyloid manifestations. The findings show that measurements of SAA and CRP concentrations are valuable in assessing disease activity and the effect of therapy in rheumatic diseases, as well as in the assessment of the prognosis in secondary amyloidosis. Therapeutic measures that decrease SAA levels may reduce amyloid formation.