Autoantibody To Salivary Gland Protein 1 As A New Diagnosis Bio-marker For Primary Sj(o|")gren’s Syndrome

Objective:Anti-salivary gland protein 1 (SP1) antibody have recently been identified in patients with Sjogren’s syndrome (SS), which has been associated with the expression of SSA and SSB antibodies. This study to determine whether anti-SP1 antibody were identified in particular subgroups of han nationality with primary Sjogren’s syndrome (pSS). To explore the significance of this antibody in the diagnosis of pSS, and to analyze its relationships with disease clinical presentation and other laboratory indexes.Methods:A total of 119 Han patients diagnosed with pSS were included.The results were compared with a population of 50 Han patients with rheumatoid arthritis (no SS) and 50 Han healthy volunteers (controls) matched for sex and age. The pSS group was divided into the following subgroups:A (SSA- and SSB-:n= 23), B (SSA+ or SSB+:n= 49), and C (SSA+ and SSB+:n= 47). The anti-SP1 antibody was detected by Westernblot, and the relationships of SP1 antibody with clinical features was analyzed by SPSS 18.0.Results:1. The results of this study revealed that anti-SP1 antibody were present in the sera of 39.5% of pSS, significantly higher than that of RA group 22%(*P= 0.029) and healthy control group 10%(***P< 0.0001), and its specificity was 84% significantly higher than that of anti-ANA antibodies.2. The combined detection of antibod ies:SP1、SSA and SSB could improved the pSS diagnose, reaching 88.2%.3.The positive rate of anti-SP1 antibody were presented in the pSS subgroups:group A(39.1%) and group B(55%) were also significantly higher than that in RA group and healthy control group (*P< 0.05).4.There was no correlation between the positive rate of anti-SP1 antibody in pSS with disease activity index ESSDAI, but the anti-SP1 antibody positive patients were most concentrated in ESSDAI≤2 group.5.The average duration of disease was 2.5 (± 1.7) years in pSS patients with anti-SP1 antibody, while was 3.68 (±2.8) years in pSS patients without anti-SP1 antibody (*P= 0.044).6.And pSS patients with lymphadenopathy domain and glandular domain have a higher rate of anti-SP1 antibody, but there was no correlation between anti-SP1 antibody in pSS with immunoglobulin (IgG), complement, RF, CCP, CRP and other indicators.Conclusions:The anti-SP1 antibody is likely to be a new diagnosis bio-marker for primary Sjogren’s syndrome. This novel autoantibody could be found in the early stage in patients with pSS, and its may be have a certain instruction function for pSS patients with lymphadenopathy domain and glandular domain have a higher rate of anti-SP1 antibody.