TY - JOUR T1 - Serum Amyloid A and C-Reactive Protein Concentrations Are Differently Associated with Markers of Autoimmunity in Patients with Primary Sjögren’s Syndrome JF - The Journal of Rheumatology JO - J Rheumatol DO - 10.3899/jrheum.090300 SP - jrheum.090300 AU - Marja Pertovaara AU - Juulia Jylhävä AU - Hannu Uusitalo AU - Juhani Pukander AU - Heikki Helin AU - Mikko Hurme Y1 - 2009/10/15 UR - http://www.jrheum.org/content/early/2009/10/09/jrheum.090300.abstract N2 - Objective Primary Sjögren’s syndrome (pSS) is an autoimmune disease in which the concentration of the acute-phase protein serum C-reactive protein (CRP) is low. We investigated whether levels of another acute-phase protein, serum amyloid A (SAA), are increased in patients with pSS and whether the immunological markers in patients with pSS are associated with variation in SAA levels. Methods Serum SAA concentrations were measured by ELISA in 74 patients with pSS and in 56 control subjects with sicca symptoms. Results Median SAA levels did not differ significantly between patients with pSS and subjects with sicca symptoms. In patients with pSS SAA concentrations correlated significantly with age, leukocyte count, CRP, interleukin 6, and C4. Unlike CRP, there was a significant inverse correlation between SAA and serum IgG levels and anti-SSA antibody titers, as well as a trend towards an inverse correlation between SAA and antinuclear antibody and rheumatoid factor titers. Conclusion Our data imply that high SAA production could constitute a protective element in pSS: high SAA levels inhibit in particular various signs of B cell hyperreactivity, i.e., IgG and autoantibody production. ER -