Search

To analyse prospectively the diagnostic sensitivity and specificity as well as the clinical relevance of ribosomal P (anti-P) autoantibodies in a large cohort of SLE patients.The anti-P autoantibodies were evaluated in the serum of 200 Tunisian SLE patients at disease onset and 130 various control subjects by a sensitive immunodot assay. A complete laboratory evaluation and clinical examination were performed in each SLE patient. During the follow-up, the patients were regularly monitored for clinical parameters. Global SLE activity was measured by the ECLAM.The sensitivity and specificity of anti-P testing for SLE were 23.5 and 98.4%, respectively. The anti-P-positive samples 14/47 (29.8%), 27/47 (57.4%) and 5/47 (10.6%) were negative for anti-dsDNA, anti-Sm or both antibodies, respectively. The anti-P-positive patients showed more active disease activity and a much higher prevalence of arthritis. An association between IgG aCLs and anti-P antibodies was also found. However, anti-P antibodies were not associated with neuropsychiatric manifestations or lupus nephritis.This study does not seem to confirm the described association of anti-P antibodies with neuropsychiatric manifestations of SLE. However, it supports the anti-P antibody association with arthritis and disease activity as well as the presence of aCL. Based on our study and other related studies, we propose that, akin to anti-Sm and anti-dsDNA, anti-P antibodies detected by one agreed method may be considered for inclusion as a criterion for the classification of SLE.

We evaluated the combined use of different fixatives for the identification of atypical perinuclear anti-neutrophil cytoplasmic antibodies (p-ANCA) in patients with inflammatory bowel diseases (IBD) by indirect immunofluorescence (IIF). Sera from 59 ulcerative colitis (UC) and 37 Crohn’s disease (CD) patients, and from 64 healthy controls were studied. The IIF on ethanol-, formalin-, and methanol-fixed neutrophils was used for the detection of ANCA. Enzyme linked immunosorbant assay (ELISA) was performed to identify the antigens recognized by ANCA. ANCAs were present in 35 of 59 (59.3%) UC patients and in 10 of 37 (27.02%) CD patients. Atypical p-ANCA positivity was strongly associated with UC disease (44.1% in UC vs. 8.1% in CD; p = 0.0002). The combined application of different fixatives contributed to make easy the differentiation between typical p-ANCA and atypical p-ANCA. Atypical p-ANCA determination appears to be a useful parameter for the distinction between UC and CD.