Department of Internal Medicine, Section of Rheumatology, Tampere University Hospital, Tampere, Finland.
J Rheumatol. 2009 Nov;36(11):2487-90. doi: 10.3899/jrheum.090300. Epub 2009 Oct 15.
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.
Serum SAA concentrations were measured by ELISA in 74 patients with pSS and in 56 control subjects with sicca symptoms.
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.
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.
原发性干燥综合征（pSS）是一种自身免疫性疾病，其急性期蛋白血清 C 反应蛋白（CRP）浓度较低。我们研究了 pSS 患者的另一种急性期蛋白血清淀粉样蛋白 A（SAA）水平是否升高，以及 pSS 患者的免疫学标志物是否与 SAA 水平的变化相关。
通过 ELISA 法检测 74 例 pSS 患者和 56 例有干燥症状的对照者的血清 SAA 浓度。
pSS 患者和有干燥症状的对照者的 SAA 水平中位数无显著差异。在 pSS 患者中，SAA 浓度与年龄、白细胞计数、CRP、白细胞介素 6 和 C4 显著相关。与 CRP 不同，SAA 与血清 IgG 水平和抗 SSA 抗体滴度呈显著负相关，与抗核抗体和类风湿因子滴度呈负相关趋势。
我们的数据表明，SAA 水平升高可能是 pSS 的一种保护因素：高 SAA 水平抑制了特别是 B 细胞过度反应的各种迹象，即 IgG 和自身抗体的产生。
