Antiribosomal P protein IgG autoantibodies are highly specific for SLE and might be associated with disease activity. (22nd February 2011)

• Record Type: Journal Article
• Authors: Fernandes, D; Santos, MJ; Fonseca, JE
• Is Part Of: Annals of the rheumatic diseases. Volume 70(2011)Supplement 2
• Page Start: A82
• Page End: A82
• Publication Date: 2011-02-22
• Subjects: Rheumatism -- Periodicals; 616.723005
• DOI: 10.1136/ard.2010.149021.1
• Languages: English
• ISSNs: 0003-4967

Abstract

Abstract : Background and objectives: Systemic lupus erythematosus (SLE) is characterised by the production of autoantibodies directed against a variety of nuclear and cytoplasmic antigens. One of these antigens is ribosomal P protein (Rib-P), a pentamer consisting of three different phosphoproteins. The aim of this work was to assess the prevalence and clinical associations of anti-Rib-P antibodies in a cohort of Portuguese SLE patients. Patients and methods: Anti-Rib-P autoantibodies were quantified in sera from 127 SLE patients, 100 healthy controls and 256 various control diseases including rheumatoid arthritis (n=100), JIA (n=34), AS (n=100) and PsA (n=22) using the EliA Rib-P (Phadia, Sweden), a fluoroenzymeimmunoassay that quantifies Rib-P specific IgG antibodies. Results: The mean value of anti-Rib-P was significantly higher in SLE patients than in healthy (p<0.001) or disease control population (p=0.002). Setting the cut-off for positivity at 4.45 U/ml as determined by Receiver Operating Characteristic (ROC) curve analysis, 18 SLE patients (14.2%) but no healthy controls were positive for anti-Rib-P autoantibodies (Rib-P-(+)) (p<0.001); in the disease control group only two rheumatoid arthritis patients were Rib-P-(+) (p<0.001). The area under the curve was 0.800 for discrimination between SLE and healthy controls (sensitivity=14.2%; specificity=100%) and 0.595 for control diseases (sensitivity=14.2%; specificity=99.2%). SLE patients Rib-P-(+) had a higher SLEDAI (p=0.005), but no association with psychosis or nephritis was found. Also there was no relation with age, age at diagnosis, gender or ethnicity. The authors also compared anti-Rib-P autoantibodies with the production of other autoantibodies (such as anti-dsDNA, anti-Sm or APL) and found no statistically significant associations. Conclusion: Considering the high specificity of this test, the authors believe that anti-Rib-P autoantibody quantification through this method might be useful in SLE diagnosis. Its value as an indicator of active disease needs to be prospectively validated.