Background: The presence of ''anti-DNA antibodies in abnormal titres'' is a well established criterion for SLE classification, but there is no agreement on the performance of this test. Objective: To study the correlation between clinical findings and five different solid and solution phase anti-DNA antibody assays. Methods: 158 consecutively collected ANA positive sera were studied in a double blind fashion. Anti-DNA antibodies were determined by different solid phase assays (ssDNA-, dsDNA-specific ELISA, EliA antidsDNA assay, Crithidia luciliae assay), and by an experimental solution phase anti-DNA assay using biotinylated pUC18 plasmid, human, calf thymus, and E coli DNA. Antibody affinity was determined by surface plasmon resonance. Clinical data were obtained independently of the laboratory analyses and later related to the anti-dsDNA findings. Results: Anti-dsDNA antibodies were most frequently detected by ELISA, but were not specific for SLE as they were present in up to 30% of other disease groups. Those detected by the Crithidia luciliae assay were predictive for SLE, while antibodies binding in solution phase ELISA using the pUC18 correlated strongly with the Crithidia luciliae assay. Surface plasmon resonance analysis showed that antibody binding to pUC18 was not due to higher relative affinity for dsDNA in general, but apparently to specificity for that plasmid DNA. Serum samples from three patients with lupus nephritis were positive in both pUC18 solution phase and Crithidia luciliae assays. Conclusions: Assay principle selection is decisive for the detection of clinically significant anti-DNA antibodies. Revision of the anti-DNA antibody criterion in the SLE classification may be needed.

Background and Purpose-We wanted to investigate whether common prothrombotic mutations are more prevalent in patients with atrial fibrillation who have had a stroke than in healthy controls. We also wanted to assess whether early recurrent ischemic cerebrovascular events were more frequent among carriers of the factor V Leiden or the prothrombin gene mutations than among others. Methods-We used a case-control design with 367 patients with acute ischemic stroke and atrial fibrillation (cases) and 482 healthy blood donors (controls). All mutations were detected with conventional polymerase-chain reaction protocols. Results-The odds ratios for carriers of the factor V Leiden, prothrombin gene 20210GA, methylenetetrahydrofolate reductase 677CT, or platelet glycoprotein IIIa 1565TC (Pl A2 ) mutation were 0.91, (95% CI, 0.51 to 1.59), 2.25 (95% CI, 0.61 to 8.90), 0.83 (0.61 to 1.13), and 0.79 (0.57 to 1.10), respectively. Early recurrent ischemic stroke and total recurrent ischemic cerebrovascular events were slightly more frequent among carriers of the factor V Leiden mutation than among noncarriers: odds ratio 1.45 (95% CI, 0.41 to 5.1), and 1.59 (0.61 to 4.1), respectively. None of the patients with recurrent ischemic cerebrovascular events had the prothrombin gene mutation. Conclusion-These mutations are not important risk factors for thromboembolic stroke associated with atrial fibrillation.Carriers of the factor V Leiden mutation had a small, nonsignificantly higher risk of early recurrent ischemic cerebrovascular events. Key Words: atrial fibrillation Ⅲ ischemic stroke Ⅲ prothrombotic gene mutations P atients with atrial fibrillation have a 5-fold increased risk of thromboembolic stroke, probably attributable to activation of blood coagulation. We wanted to investigate whether common prothrombotic mutations are more prevalent in patients with atrial fibrillation who have had a thromboembolic stroke than in healthy controls. We also wanted to investigate whether, among patients with acute ischemic stroke and atrial fibrillation, early recurrent ischemic cerebrovascular events were more frequent in carriers of the most important of these gene mutations than in noncarriers.We chose to screen for the factor V Leiden, prothrombin gene 20210GA, methylenetetrahydrofolate reductase (MTHFR) 677CT, and platelet glycoprotein (GP) IIIa 1565TC mutations. The factor V Leiden and the prothrombin gene mutations are associated with increased risk of venous thromboembolism 1,2 and possibly myocardial infarction and stroke. 3 The MTHFR mutation increases plasma homocysteine, which has emerged as a potential risk factor for cardiovascular diseases, including stroke. 4 The mutant Pl A2 allele in the platelet GPIIIa gene is associated with increased risk of coronary thrombosis 5 and stroke in young patients. 6 Materials and MethodsCases were 367 patients with acute ischemic stroke and atrial fibrillation, of which 355 had been included in the Heparin in Acute Embolic Stroke Trial (HAEST). 7 Controls were unselected healthy subjects ...

This study investigated the overall clinical impact of anti-α-actinin antibodies in patients with pre-selected autoimmune diseases and in a random group of anti-nuclear antibody (ANA)-positive individuals. The relation of anti-α-actinin antibodies with lupus nephritis and anti-double-stranded DNA (anti-dsDNA) antibodies represented a particular focus for the study. Using a cross-sectional design, the presence of antibodies to α-actinin was studied in selected groups, classified according to the relevant American College of Rheumatology classification criteria for systemic lupus erythematosus (SLE) (n = 99), rheumatoid arthritis (RA) (n = 68), Wegener's granulomatosis (WG) (n = 85), and fibromyalgia (FM) (n = 29), and in a random group of ANA-positive individuals (n = 142). Renal disease was defined as (increased) proteinuria with haematuria or presence of cellular casts. Sera from SLE, RA, and Sjøgren's syndrome (SS) patients had significantly higher levels of anti-α-actinin antibodies than the other patient groups. Using the geometric mean (± 2 standard deviations) in FM patients as the upper cutoff, 20% of SLE patients, 12% of RA patients, 4% of SS patients, and none of the WG patients were positive for anti-α-actinin antibodies. Within the SLE cohort, anti-α-actinin antibody levels were higher in patients with renal flares (p = 0.02) and correlated independently with anti-dsDNA antibody levels by enzyme-linked immunosorbent assay (p < 0.007) but not with other disease features. In the random ANA group, 14 individuals had anti-α-actinin antibodies. Of these, 36% had SLE, while 64% suffered from other, mostly autoimmune, disorders. Antibodies binding to α-actinin were detected in 20% of SLE patients but were not specific for SLE. They correlate with anti-dsDNA antibody levels, implying in vitro crossreactivity of anti-dsDNA antibodies, which may explain the observed association with renal disease in SLE.

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