Diagnostic Significance Of Anti-alpha-Fodrin Antibodies And Importance Of The Regulatory T Cells In The Pathogenesis In Sj(?)gren's Syndrome

Sj?gren's syndrome (SS) is an antigens drove,T cells mediated and B cells activated autoimmune disease without perfect serological diagnostic methods. The abnormalities of the T cell function is thought to play an important role in the SS pathogenesis. The alpha -fodrin was correlated with SS. To explore the diagnostic significance of anti-alpha-fodrin antibodies and the importance of abnormalities of regulatory T cells (Treg) in the pathogenesis of SS, we carried out the following studies.Our study consists of two sections:Section I : The diagnostic significance of anti-alpha-fodrin polypeptide IgA antibodies in SSThis study explore that the diagnostic significance of IgA antibodies response against recombinant alpha-fodrin polypeptide detected by the ELISA test in SS.1.The screening of recombinant alpha-fodrin polypeptideThis study detected the IgA antibodies response against recombinant alpha-fodrin polypeptide 1-5 by the ELISA test. It shows that, the positive rate of 5th alpha-fodrin polypeptide which amino acid sequence is RQKLEDSYRFQFFQRDAEELEKW( p<0.05) was the highest.2. The significance of anti-alpha-fodrin polypeptide IgA antibodies in diagnosis and clinical application of SSThe antibodies against alpha-fodrin polypeptide were detected by ELISA test in 52.8% of patients with primary SS, 64.5% of patients with SS, 17.8% of patients with SLE and 27.3% of patients with RA, and the OD values of primary and secondary SS were higher than the OD values of SLE and RA. The sensitivity of anti-alpha-fodrin polypeptide IgA antibodies was higher than anti-SSA antibody, anti-SSB antibody and ANA in primary SS and the specificity was close to each other. The anti-alpha-fodrin polypeptide IgA antibodies is an early diagnostic marker in primary SS because the positive rates of anti-alpha-fodrin polypeptide IgA antibodies in the pSS without anti-SSA antibody, anti-SSB antibody , ANA were 46.7%, 51.5%, 57.1% in order. The presence of anti-alpha-fodrin polypeptide IgA antibodies were associated with the manifestations, such as renal disorder, vasculitis and the laboratory tests, such as ascensus of IgG and IgA level, increasing of erythrocyte sedimentation rate, descending of WBC and PLT. It's mean that anti-alpha-fodrin polypeptide IgA antibodies were associated with activity of disease.Section II: The establishment and identification of animal model for Sj?gren's syndrome and studies of Treg in model rat of SSThe abnormalities of the T cell function is thought to play an important role in the SS pathogenesis.To further investigate the role of the Treg in the pathogenesis of SS, this study adopts the SS animal model-the submandibular gland(SMG) homogenate inducted Lewis rats as the research object. The level of Treg was examined using the FACS analysis for CD4+CD25+ T cells and realtime quantitative PCR for Foxp3 expression level in various lymphoid organs of the model rats.1.The establishment and identification of SMG homogenate inducted rats for SSThis study uses a homogenate of submandibular gland tissue from male Lewis rats as antigen for induction of Sj?gren's syndrome in female Lewis rats. The results show that, the drinking water quantity and submaxillary salivary gland index of SS model rats were also higher than the normal and adjuvant control, and the submaxillaritis was found in the pathology of SS model rats. It is negative that the antibodies against SSA, SSB and ANA were detected in the SS model rats, normal and adjuvant control. The anti-alpha-fodrin polypeptide IgG antibodies were detected by ELISA test in SS model rats and the OD value was the highest in the 14th day after immunized.2. The chance of Treg level in various lymphoid organs of the SS model ratsThis study uses the realtime quantitative PCR to analyze the Foxp3 expression level and FACS to detect ratio of CD4+CD25+T cells in various lymphoid organs of the SS model rats. The results show that, the Foxp3 expression level and ratio of CD4+CD25+T cells in various lymphoid organs of the SS model rats were lower than the normal and adjuvant control obviously (p<0.001). The level of Treg in peripheral lymphoid organs, such as spleen and submandibular lymph nodes were positive correlation with the level of Treg in thymus gland.The innovation of this study is: (1) we found the positive rate and OD value of anti-alpha-fodrin polypeptide IgA antibodies in SS were higher than disease control groups for the first time at home. The sensitivity and specificity of anti-alpha-fodrin polypeptide IgA antibodies in SS were higher, anti-alpha-fodrin polypeptide IgA antibodies were detected in the pSS patients without anti-SSA antibody, anti-SSB antibody, ANA, and were associated with activity of disease. Accordingly, the anti-alpha-fodrin polypeptide IgA antibodies are a relative specific autoantibodies and an important diagnostic significance in SS, would be regarded as a new marker to monitor activity of disease. (2) We successfully used a homogenate of submandibular gland tissue from male Lewis rats as antigen for induction of Sj?gren's syndrome in female Lewis rats and detected the anti-alpha-fodrin polypeptide IgG antibodies by ELISA test in the serums of SS model rats for the first time. At the same time, we found the level of Treg descended both in thymus and peripheral lymphoid organs, such as spleen and submandibular lymph nodes for the first time, and the level of Treg in peripheral lymphoid organs were positive correlation with the level of Treg in thymus, which can cue the reduction of the Treg in thymus is an important reason in the pathogenesis of SS. This study provides the experimental data for further investigating the pathogenesis of the SS.