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Objective: An Italian multicentre study was promoted in order to assess the accuracy of four anti-double-stranded DNA (dsDNA) antibody assays for SLE diagnosis and monitoring. Methods: Two hundred and twenty-three patients with established SLE according to ACR classification criteria were enrolled from 9 centres. They included 59 patients at first evaluation (disease duration <12 months) and 164 with longer disease duration (median disease duration 120 months). The sera from 55 healthy subjects and 161 patients with rheumatic, infectious or neoplastic diseases were tested as controls. SLE activity was measured by ECLAM score. Anti-dsDNA antibodies were detected in serum by means of FarrzymeTM assay, fluoroenzymeimmunoassay (EliATM), Crithidia luciliae indirect immunofluorescence (CLIFT) or Farr radioimmunoassay (Farr). Cut-off values of quantitative assays were chosen by ROC curves analysis. Statistics were conducted by SPSS software package. Results: Sensitivity for SLE diagnosis ranged between 66% with Farrzyme to 95% with Farr, with about 90% specificity for all the methods tested. Farrzyme assay was more specific than the others towards patients with non-SLE connective tissue disease. The four methods were moderately concordant and correlated among them, all showing a positive association with active disease, renal or haematologic involvement, and a negative association with central nervous system disease. Whatever the assay used, anti-dsDNA antibody levels correlated with disease activity with r correlation coefficients ranging from 0.336 to 0.425 (p<0.0001). Conclusion: The diagnostic accuracy for SLE of evaluated anti-dsDNA antibody assays is comparable and potentially improvable especially in terms of specificity. The clinical adherence of the assays confirms the value of anti-dsDNA antibody for SLE monitoring

Objectives: To validate the clinical significance of anti-IFI16 autoantibodies in SSc and assess their associations with serological markers of SSc. Methods: A semi-quantitative ELISA was used to detect anti-IFI16 autoantibodies in the sera of 344 SSc patients from seven Italian hospitals and 144 healthy controls. SSc-associated autoantibodies [anti-RNA polymerase III (anti-RNAP III) antibodies, anti-centromere, anti-topo I] and IF patterns were evaluated using commercial assays. Statistical analyses were performed to test clinical and serological associations. Results: The results of this study confirm a significant prevalence (29%) of anti-IFI16 antibodies in the SSc population (n = 344). Anti-IFI16 antibodies were also detected in 30% of the SSc patients who tested negative for both ACAs and anti-topo I (anti-Scl70) antibodies. In this subgroup of patients, anti-IFI16 antibodies were significantly associated with the limited cutaneous form of SSc with a sensitivity of 40% and a specificity of 81%. Moreover, analysis of the distribution of anti-RNAP III antibodies vs anti-IFI16 in the same SSc population showed that they were mutually exclusive. IIF revealed no association between anti-IFI16 and fluoroscopic patterns, due to a lack of IFI16 autoantigen in HEp-2 cells. Anti-IFI16 antibody levels were also significantly associated with heart involvement. Conclusions: Anti-IFI16 autoantibodies are frequently detected in SSc, displaying clinical and laboratory associations, and being particularly useful for diagnosis and disease classification in patients who are negative for other SSc serological markers. © The Author 2010. Published by Oxford University Press on behalf of the British Society for Rheumatology. All rights reserved.

Objective: Prothrombin (PT) is a target for antibodies with lupus anticoagulant (LA) activity, suggesting the possible application of anti-prothrombin antibody (aPT) assays in patients with antiphospholipid syndrome (APS). Different methods - both homemade and commercial - for the detection of aPT are available, but they seem to produce conflicting results. The purpose of this study was to compare the performance of different assays on a set of well-characterized serum samples. Patients and methods: Sera were gathered from 4 FIRMA institutions, and distributed to 15 participating centres. Forty-five samples were from patients positive for LA and/or anticardiolipin antibodies (aCL) with or without APS, and 15 were from rheumatoid arthritis (RA) patients negative for antiphospholipid antibodies. The samples were evaluated for IgG and IgM antibodies using a homemade direct aPT assay (method 1), a homemade phosphatidylserine-dependent aPT assay (aPS/PT, method 2), and two different commercial kits (methods 3 and 4). In addition, a commercial kit for the detection of IgG-A-M aPT (method 5) was used. Results: Inter-laboratory results for the 5 methods were not always comparable when different methods were used. Good inter-assay concordance was found for IgG antibodies evaluated using methods 1, 3, and 4 (Cohen k > 0.4), while the IgM results were discordant between assays. In patients with thrombosis and pregnancy losses, method 5 performed better than the others. Conclusion: While aPT and aPS/PT assays could be of interest from a clinical perspective, their routine performance cannot yet be recommended because of problems connected with the reproducibility and interpretation of the results

The "Euro-Lupus Cohort" is composed by 1000 patients with systemic lupus erythematosus (SLE) that have been followed prospectively since 1991. These patients have been gathered by a European consortium-the "Euro-Lupus Project Group". This consortium was originated as part of the network promoted by the "European Working Party on SLE", a working group created in 1990 in order to promote research in Europe on the different problems related to this disease. The "Euro-Lupus Cohort" provides an updated information on the SLE morbidity and mortality characteristics in the present decade as well as defines several clinical and immunological prognostic factors. © 2005 Elsevier B.V. All rights reserved.

The "Euro-Lupus Cohort" is composed by 1,000 patients with systemic lupus erythematosus (SLE) that have been followed prospectively since 1991. These patients have been gathered by a European consortium - the "Euro-Lupus Project Group". This consortium was originated as part of the network promoted by the "European Working Party on SLE", a working group created in 1990 in order to promote research in Europe on the different problems related to this disease. The "Euro-Lupus Cohort" provides an updated information on the SLE morbidity and mortality characteristics in the present decade as well as defines several clinical and immunological prognostic factors

OBJECTIVE: To test the prevalence of anti-neutrophil cytoplasmic antibodies (ANCA) in systemic sclerosis (SSc) and to verify a possible association of ANCA with normotensive renal involvement in SSc. PATIENTS AND METHODS: 51 patients affected by SSc, 35 with diffuse scleroderma (dSSc) and 16 with limited scleroderma (lSSc), were tested for ANCA by indirect immunofluorescence (IIF) on human ethanol and formalin-acetone-fixed granulocytes (before and after DNase treatment), by conventional enzyme linked immuno-sorbent assay (ELISA) and by capture-ELISA. RESULTS: Six out of 51 selected SSc patients had ANCA by IIF (11.7%) and five presented a perinuclear/nuclear atypical ANCA pattern. In all cases we only found anti-proteinase3 (aPR3) antibodies. All ANCA positive patients had diffuse form of SSc (17.1%), all were anti-Scl70 positive (aScl70), five patients had proteinuria, three had microscopic haematuria. All ANCA positive patients were normotensive with normal renin plasma levels, the mean erythrocyte sedimentation rate (ESR) was higher in this group compared to the other SSc patients. CONCLUSIONS: Our study shows that aPR3 is not rare in dSSc. According to the clinical and serological findings and to the recent literature, we can hypothesise that when ANCA are found in SSc, an overlapping of scleroderma with systemic necrotizing vasculitis should be suspected

Objective The SA1 and 16/6 idiotypes can be found in some patients with systemic lupus erythematosus (SLE) or antiphospholipid syndrome (APS). The aim of this study was to ascertain the prevalence of these idiotypes in a large cohort of SLE patients, and to determine whether their presence is correlated with the anticardiolipin (aCL) and anti-dsDNA antibodies or with the clinical manifestations of SLE. Methods 492 SLE patients were evaluated for clinical manifestations of SLE and were assigned a disease severity score. ds-DNA autoantibodies, aCL autoantibodies of the IgM, Ige and IgA isotypes, and SA1 and 16/6 idiotypes were also determined in these patients. Results The prevalence of the SA1 and 16/6 idiotypes in the 492 SLE patients was found to be 11% and 5.1%, respectively, and these idiotypes were significantly more prevalent in the patients who had aCL antibodies of either the IgG, IgM or IgA isotypes. Moreover, while the 16/6 idiotype was not associated with the clinical manifestation of either SLE or APS, the SA1 idiotype was found significantly more frequently in patients who had vascular events, Raynaud's phenomenon or hemolytic anemia (p = 0016, 0.01, 0.01, respectively). Conclusion SLE patients with the SA1 idiotype may run a higher risk of developing vascular events, Raynaud's phenomenon or hemolytic anemia. These clinical manifestations can be attributed to both SLE and secondary APS when aCL autoantibodies are also found. These results indicate that the possible pathogenicity of certain idiotypes in SLE cannot be excluded.