Autoantibodies against dsDNA measured with nonradioactive Farr assay-an alternative for routine laboratories.

Autoantibodies against dsDNA are utilized for the diagnosis and prognosis of SLE as they are highly specific and correlate with disease activity/renal involvement. However, different detection methods are used in routine diagnostic laboratories. Farr radioimmunoassay (Farr-RIA) has been designated as the preferred method, since it provides very specific and at the same time quantitative results, enabling follow-up of level variations over time.

Anti-Phosphatidylserine/Prothrombin Antibodies Are Associated with Adverse Pregnancy Outcomes.

Objective. To determine the prevalence and clinical association of anti-phosphatidylserine/prothrombin antibodies (aPS/PT) in patients with a history of pregnancy complications relevant to antiphospholipid syndrome (APS). Materials and Methods.

Anti-β2-glycoprotein I paratopes and β2-glycoprotein I epitopes characterization using random peptide libraries.

Studies concerning interactions between anti-β2-glycoprotein I antibodies (anti-β2GPI) and β2-glycoprotein I (β2GPI) suggest relevance of charge interactions and hydrogen bonds. However, paratope of diagnostically and clinically relevant anti-β2GPI and epitope characteristics of β2GPI, still remain unclear. The aim of our study was to determine paratope characteristics of various anti-β2GPI antibodies and epitope characteristics of β2GPI using phage display.

Detection of antiphosphatidylserine/prothrombin antibodies and their potential diagnostic value.

Antiprothrombin antibodies, measured with phosphatidylserine/prothrombin complex (aPS/PT) ELISA, have been reported to be associated with antiphospholipid syndrome (APS). They are currently being evaluated as a potential classification criterion for this autoimmune disease, characterized by thromboses and obstetric complications. Given the present lack of clinically useful tests for the accurate diagnosis of APS, we aimed to evaluate in-house and commercial assays for determination of aPS/PT as a potential serological marker for APS.

Antibodies to phosphatidylserine/prothrombin complex as an additional diagnostic marker of APS?

Antiprothrombin antibodies can be measured by ELISA using either a prothrombin/phosphatidylserine complex (aPS/PT) or prothrombin alone (aPT) as antigen. We aimed to compare the clinical features of autoimmune patients with avidity of aPS/PT and determine the diagnostic efficiency of aPS/PT and aPT for assessing antiphospholipid syndrome (APS). aPS/PT were of low (n = 9), heterogeneous (n = 31) and high (n = 8) avidity out of 48 cases.

Avidity of anti-β2-glycoprotein I antibodies in patients with antiphospholipid syndrome.

Antibodies against β(2)-glycoprotein I (anti-β(2)GPI) are one of the hallmarks of the antiphospholipid syndrome (APS). However, they are heterogenic regarding their epitope specificity, pathogenic mechanisms and their avidity. In the current study we present some outstanding issues about avidity of anti-β(2)GPI antibodies.

Safety and efficacy of influenza vaccination in a prospective longitudinal study of 31 children with juvenile idiopathic arthritis.

Objectives: Influenza vaccination in children with rheumatic diseases is often recommended, but not frequently performed. Our aim was to assess the safety and efficacy of annual influenza vaccination in a longitudinal follow-up study of an unselected group of children with juvenile idiopathic arthritis (JIA).

Methods: Thirty-one children with stable JIA (10 boys, 21 girls, mean age 11.

Autoimmune response following influenza vaccination in patients with autoimmune inflammatory rheumatic disease.

Vaccines have undoubtedly brought overwhelming benefits to mankind and are considered safe and effective. Nevertheless, they can occasionally stimulate autoantibody production or even a recently defined syndrome known as autoimmune/inflammatory syndrome induced by adjuvants (ASIA). There is scarce data regarding autoimmune response after seasonal/influenza A (H1N1) vaccine in patients with autoimmune inflammatory rheumatic disease (AIRD).

International cohort study of 73 anti-Ku-positive patients: association of p70/p80 anti-Ku antibodies with joint/bone features and differentiation of disease populations by using principal-components analysis.

Introduction: An international cohort study of 73 anti-Ku-positive patients with different connective tissue diseases was conducted to differentiate the anti-Ku-positive populations of patients based on their autoantibody profile and clinical signs/symptoms and to establish possible correlations between antibodies against Ku p70 and Ku p80 with autoimmune diseases.

Methods: Sera of anti-Ku-positive patients were collected from six European centers and were all secondarily tested (in the reference center); 73 were confirmed as positive. Anti-Ku antibodies were detected with counter-immunoelectrophoresis (CIE), line immunoassay (LIA), and immunoblot analyses.

Autoimmune reactivity of IgM acquired after oxidation.

Objectives: Redox-reactive antibodies, mainly of the IgG class, gained a wide area of interest after their autoimmune reactivity was revealed following the application of chemical and physiological oxidants. In this study, we examined the susceptibility of IgMs to oxidation and evaluated their binding to the autoantigens important in some autoimmune diseases.

Methods: IgM and IgG fractions, isolated from healthy individuals' sera, were oxidized using direct electric current or physiological oxidant hemin.

Comparison and evaluation of different methodologies and tests for detection of anti-dsDNA antibodies on 889 Slovenian patients' and blood donors' sera.

Aim: To evaluate four different commercially available assays for anti-double stranded DNA (dsDNA) detection and compare them with the in-house radioimmunoassay according to Farr (FARR-RIA) in order to select the optimal primary method for use in combination with FARR-RIA.

Methods: Sera from 583 consecutive patients sent to our laboratory for routine diagnosis, 156 selected patients with autoimmune diseases (76 systemic lupus erythematosus [SLE] patients and 80 patients with other autoimmune diseases), and 150 blood donors were tested for anti-dsDNA antibodies with two enzyme-linked immunoassays (ELISA), two Crithidia luciliae immunofluorescence tests (CLIFT), and FARR-RIA. The specificities and sensitivities of the tests were calculated and compared.

Significance of K(L/V)WX(I/L/V)P Epitope of the B2Gpi in Its (Patho)Physiologic Function.

β2-glycoprotein I (β2GPI) is a major autoantigen of autoimmune thrombophilia, known as the antiphospholipid syndrome. The exact mechanism underlying the β2GPI's involvement in the disease is not fully elucidated, as it is not its physiological role. We used random phage peptide library to identify sequences binding to β2GPI.

Antiphospholipid antibodies and atherosclerosis: insights from rheumatoid arthritis--a five-year follow-up study.

Objectives: Life expectancy in rheumatoid arthritis (RA) patients is reduced by 3-10 years, probably due to cerebrovascular and cardiovascular diseases associated with atherosclerosis. In the present study, we wanted to verify if previously reported IgA anti-beta 2-glycoprotein I (2GPI) antibodies possibly represented an independent risk factor for atherosclerosis in RA patients during a longer period of follow up.

Methods: The follow-up study (after 5.

The avidity of anti-beta2-glycoprotein I antibodies in patients with or without antiphospholipid syndrome: a collaborative study in the frame of the European forum on antiphospholipid antibodies.

Objective: The objective of this study was to extend the findings of the preliminary study by measuring the avidity of IgG anti-β2-glycoprotein I antibodies (anti-β2-GPI) on a larger group of patients with primary or secondary antiphospholipid syndrome (APS) and anti-β2-GPI positive patients without APS in the frame of the European Forum on antiphospholipid antibodies (aPL).

Methods: Serum from 137 patients with primary APS, APS associated with autoimmune diseases, and patients with autoimmune diseases other than APS from five EU rheumatology centres were tested for anti-β2-GPI antibodies. The 109 patients who were sera positive for anti-β2-GPI by the in-house anti-β2-GPI enzyme-linked immunosorbent assay (ELISA) at the Immunology Laboratory, UMC Ljubljana were selected for further testing on avidity with chaotropic anti-β2-GPI ELISA.

Immunochemical properties and pathological relevance of anti-β₂-glycoprotein I antibodies of different avidity.

Despite available treatment, there is still significant morbidity and mortality present among patients with the autoimmune thrombophilic condition termed 'antiphospholipid syndrome' (Espinosa, G. and Cervera, R. 2009.

Modified phosphatidylserine-dependent antiprothrombin [corrected] ELISA enables identification of patients negative for other antiphospholipid antibodies and also detects low avidity antibodies.

Background: Two approaches for detecting anti-prothrombin antibodies have been described. The first detects antibodies against prothrombin alone and the second, phos-phatidylserine-dependent antiprothrombin antibodies. The latter more often correlate with clinical manifestations of antiphospholipid syndrome and with lupus anticoagulant activity.

Alteration of antibody specificity during isolation and storage.

Isolation buffer characteristics and storage conditions could partially transform natural antibodies. 50 IgG factions were isolated from seven healthy donors' sera using various protein G columns and buffers. PAGE revealed no major antibody cleavages; purity of IgGs eluted at pH 2.

Rational Laboratory Diagnostics of Antiphospholipid Antibodies: Anti-Cardiolipin, Anti-β2-Glycoprotein I, Anti-Prothrombin and Anti-Annexin V Antibodies.

A possible co-appearance of anticardiolipin (aCL), anti-β2-glycoprotein I (anti-β2-GPI), anti-prothrombin (aPT) and anti-annexin V (aANXV) antibodies of IgG, IgM and IgA class were studied in 58 patients with SLE alone and 32 patients APS in the view of rational laboratory diagnostics. The presence of anti-phospholipid antibodies (aPL) were defined by our in-house ELISA methods. Out of 17 aCL negative SLE patients 6 had other antigenically defined aPL antibodies.

The association between circulating antibodies against domain I of beta2-glycoprotein I and thrombosis: an international multicenter study.

Background: Diagnosis of the antiphospholipid syndrome (APS) is difficult as a result of limited specificity of existing assays for detecting clinically relevant antiphospholipid antibodies. Anti-beta2-glycoprotein I (beta 2GPI) antibodies play a central role in the disease process of APS.

Objectives: We have investigated the relation between antiphospholipid antibodies with specificity for domain I of beta 2GPI and thrombosis/pregnancy morbidity in an international multicenter study.

Autoimmune response following annual influenza vaccination in 92 apparently healthy adults.

Objective: To evaluate the possibility of autoimmune responses following annual influenza vaccination in a large cohort of apparently healthy adults.

Methods: Autoantibodies including antinuclear antibodies (ANA), anticardiolipin antibodies (aCL), anti-beta(2)-glycoprotein I antibodies (anti-beta(2)-GPI), lupus anticoagulant (LA) and anti-extractable nuclear antigen antibodies (anti-ENA) were determined in 92 healthy adult subjects, staff at the University Children's Hospital Ljubljana. Blood samples were taken from each participant before the vaccination, 1 month and 6 months after the annual influenza vaccination.

Autoimmune and proinflammatory activity of oxidized immunoglobulins.

Aims: Oxidation reactions can modify protein activity or specificity. Recently, a novel redox-reactive family of autoantibodies was described, which indicated involvement of altered antibodies (beside altered antigens) into autoimmune reactions. The aim of our study was to determine the binding capacity alterations of electro-oxidized blood donors' IgGs, and to evaluate their effects on released proinflammatory interleukin 6 in HUVEC.

Prevalence and clinical associations of anti-Ku antibodies in patients with systemic sclerosis: a European EUSTAR-initiated multi-centre case-control study.

Objectives: To determine the prevalence of anti-Ku antibodies in 625 patients with systemic sclerosis (SSc) from six European rheumatological centres and to evaluate their clinical and serological characteristics.

Methods: Sera of 625 consecutive patients with either limited cutaneous or diffuse cutaneous SSc were tested for antibodies to Ku antigen together with other extractable nuclear antigens by counterimmunoelectrophoresis. A case-control design with calculation of bootstrap 95% confidence intervals derived from anti-Ku negative control patients was used to evaluate clinical associations of anti-Ku antibodies.

Autoantibodies in nonautoimmune individuals during infections.

Infections can act as environmental triggers inducing or promoting autoimmune disease in genetically predisposed individuals. Identification of microbial peptides similar to self-tissues may by molecular mimicry, provide the inducing mechanism for an immune response. The aim of this study was to identify autoantibodies (autoAbs) in nonautoimmune individuals during acute bacterial, viral, or parasitic infections.

Autoimmune reactions after electro-oxidation of IgG from healthy persons: relevance of electric current and antioxidants.

Proteins, including immunoglobulins, can be modified by oxidation. Extensive oxidation of immunoglobulins leads to denaturation and loss of biological activity, while initial steps of oxidation may change their specificity due to chemical alteration of the paratope. Electro-oxidation of the IgG fraction from healthy persons progress to auto-immunoreactivity, as shown for several autoantibodies including anti-beta2-glycoprotein I.

Anti-beta 2-glycoprotein I antibodies of IgM class are linked to thrombotic disorders in young women without autoimmune disease.

Antiphospholipid autoantibodies particularly antibodies against beta2-glycoprotein I (anti-beta2GPI) are casually associated with thromboses in patients with autoimmune diseases. However, their exact prevalence and role in the pathogenesis of thromboses in the absence of autoimmune disease is still inconclusive. They might be particularly important when other risk factors of thrombosis are absent.