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T Kveder

Publications and source records attributed to T Kveder.

33 records · Page 2Linked to original sources
PubMed2000

Anti-beta2-glycoprotein I ELISA: methodology, determination of cut-off values in 434 healthy Caucasians and evaluation of monoclonal antibodies as possible international standards.

Antibodies against beta2-glycoprotein I are among the most commonly detected subset of antiphospholipid antibodies. The inter-laboratory comparability of results is hardly possible due to methodological differences, lack of international standards and different cut-off values. We evaluated an ELISA for the detection of anti-beta2-glycoprotein I using the analytical goals based on biological variations for similar analytes (immunoglobulins). By our ELISA we fulfilled the optimal (IgA, IgM) or minimal (IgG) analytical goals in long-term imprecision. The determination of cut-off values was based on the frequency distribution of results obtained on 434 healthy Caucasians. To aim at a better inter-laboratory comparability we tested two monoclonal antibodies as possible calibrators: HCAL (IgG) and EY2C9 (IgM). Binding properties determined by dilutional curves showed great similarities with polyclonal sera, used as in-house standards. Cut-off values were expressed by concentrations of IgG and IgM monoclonal antibodies (4.5 and 25.3 microg/l). Our study shows the possibility for a successful application of analytical goals based on biological variation even when data for a particular analyte are not available. The expression of cut-off values, obtained on a large scale Caucasian population, by the concentration of IgG and IgM monoclonal antibodies could make possible a more reliable inter-laboratory comparison of data.

Adolescent↗
PubMed1999

Prevalence of Sjögren's syndrome in Slovenia.

OBJECTIVE: The aim of our study was to determine the prevalence of Sjögren's syndrome (SS) in Slovenia. METHODS: A total of 889 randomly selected adults were invited to take part in our study. The classification of SS was based on the validated criteria reported by a multicentre study performed in Europe. The participants were asked six simple questions for assessing both ocular and oral involvement. Information on co-morbidities and related treatment was collected at the same time. All participants were subjected to a Schirmer-I test, an unstimulated salivary flow test, as well as serological studies (rheumatoid factor, antinuclear antibodies, anti-Ro/SS-A and anti-La/SS-B antibodies). When indicated, Rose Bengal score, salivary scintigraphy and histopathological investigation of the minor salivary glands were carried out until three out of the six European classification criteria for SS were shown to be negative or until SS was diagnosed. RESULTS: Out of the 889 invited subjects, 332 (37.3%) participated in our study: 183 females, mean age (+/- S.D.) 52.2 +/- 13.7 yr (range 20-84) and 149 males, mean age (+/- S.D.) 56.3 +/- 12.9 yr (range 23-84). After the first visit, 244 of the 332 (73.5%) participants proved to be negative for three out of the six above-mentioned criteria, and were eliminated from further tests. The remaining 88 participants were consecutively subjected to Rose Bengal score, salivary scintigraphy and minor salivary gland biopsy. Fifteen participants refused to perform either one or more of the proposed tests at the second study stage. Two females of the 332 study participants [0.60% (exact 95% CI 0.07%, 2.16%)] fulfilled the criteria for primary SS. CONCLUSIONS: The estimated prevalence of definite SS in Slovenia is 0.60%.

Adult↗
PubMed1997

Influence of degraded phosphatidylserine on binding of antiphospholipid antibodies.

BACKGROUND: Antiphospholipid antibodies (aPL) show great heterogeneity. Different phospholipids, with or without protein cofactor(s), and phospholipid binding proteins alone have been proposed as the target molecules for aPL. In order to determine the influence of phospholipid degradation products on the binding of aPL, sera from 6 patients with the antiphospholipid syndrome were studied. METHODS: Fresh and aged phosphatidylserine and cardiolipin were used as coating reagents in solid-phase immunoassay procedures. Antibody reactivity was tested by enzyme-linked immunosorbent assay in the sera and in eluates from columns packed with polystyrene scrapings coated with either cardiolipin or phoshatidylserine. RESULTS: Three reaction patterns of affinity-purified antibodies were seen: (1) reactivity with phosphatidylserine but not with cardiolipin or degraded phosphatidylserine, (2) reactivity with cardiolipin and degraded phosphatidlyserine, and (3) reactivity with all three phospholipid antigens. CONCLUSIONS: Striking differences in the antiphospholipid antibody reactivity with cardiolipin, phosphatidylserine and degraded phosphatidylserine in the presence of serum proteins were observed among patients with venous thromboembolism. The analyses showed that the degradation of phosphatidylserine influences the binding of aPL in in vitro assays.

Adolescent↗
PubMed1992

Antimitochondrial (pyruvate dehydrogenase) autoantibodies in autoimmune rheumatic diseases.

Anti-pyruvate dehydrogenase (PDH) antibodies were determined in 1451 sera of patients with primary biliary cirrhosis (PBC) and several autoimmune rheumatic conditions by ELISA and immunoblotting. They were detected in sera of 93% of the patients with PBC (179 of 192 patients) in 60 of 277 (22%) patients with Sjogren's syndrome (SjS), 34 of 437 (8%) patients with scleroderma, 33 of 191 patients with SLE (17%), and 5 of 55 (10%) patients with rheumatoid arthritis (RA) but in none of the patients with polymyositis or the antiphospholipid syndrome. The ELISA studies were confirmed by immunoblots showing binding of autoimmune rheumatic sera to the same epitope (74 kd) of mitochondria that the PBC sera reacted with. The identical binding characteristics were also confirmed by protein competition assays with purified PDH. In 4 of 53 patients with SjS who were positive for anti-PDH, high titers as in PBC were detected. The anti-PDH antibodies in Sjogren's patients were associated with deranged liver function tests and extraglandular features but did not correlate with any other non-organ-specific antibody. Follow-up studies confirmed the association of the emergence of anti-PDH antibodies with defects in liver function tests. The antibodies were more prevalent in SLE and RA when they were associated with Sjogren's syndrome (30 and 18.8%, respectively). Among patients with different forms of scleroderma, anti-PDH antibodies were noted in subjects with systemic sclerosis, morphea, and Raynaud's phenomenon.(ABSTRACT TRUNCATED AT 250 WORDS)

Antibodies, Antinuclear↗
PubMed1992

Mixed connective tissue disease associated with autoimmune hepatitis and thyroiditis.

The case is reported of a 27 year old woman who had mixed connective tissue disease (MCTD) associated with chronic active hepatitis and thyroiditis. Although hepatomegaly is sometimes observed in MCTD, only four cases of MCTD and chronic active hepatitis have been described. It is thought that this is the first report of an association between MCTD, chronic active hepatitis and thyroiditis.

Adult↗
PubMed1991

Prevalence of antiphospholipid antibodies in deep vein thrombosis and their relationship to blood coagulation and fibrinolysis.

Elevated levels of antiphospholipid antibodies are associated with an increased risk of thrombosis. To establish the prevalence of these antibodies in deep vein thrombosis (DVT), IgG and IgM antibodies to cardiolipin (aCL) and phosphatidylserine (aPS) were determined by enzyme-linked immunosorbent assay in 118 patients with DVT either during an acute episode (N = 53) or at least 2 months after acute DVT (N = 65). Most patients (76%) had proximal leg DVT and no one had evident autoimmune disorder. aCL and aPS values higher than 4 standard deviations above the mean value of the control group (147 blood donors) were considered increased. Increased IgG aCL were observed in 10% of DVT patients (controls: 5%, not significant), increased IgG aPS in 16% of DVT patients (controls: 5%, p less than 0.005) and both types in 4% of DVT patients (controls: 3%, not significant). In the subgroup of 41 patients with previous idiopathic DVT, prevalence of increased IgG aPS was the highest: 27% (p less than 0.001). Increased antibodies of IgM isotype were observed in 3% (aCL) and 2% (aPS) of all DVT patients (controls: 8% and 4%, respectively, not significant). Elevated IgG aCL or aPS were not associated with significant changes in platelet count, antithrombin III and protein C. However, in patients with increased IgG aPS deficient fibrinolysis due to high plasminogen activator inhibitor activity was observed before and after 20 min upper arm venous occlusion. DVT patients with increased IgG aPS might be exposed to a greater risk of rethrombosis due to deficient fibrinolysis than DVT patients without these antibodies.

Adolescent↗
PubMed1991

The use of adenovirus-infected HeLa cells for the detection of low titer autoantibodies.

Following infection of HeLa cells with adenovirus type 5 the cellular La protein becomes predominantly associated with the virally encoded RNA polymerase III products VAI, and VAII, while most of the host RNA polymerase II (e.g. U1, U2, U4, U5 and mRNA) and RNA polymerase III transcription (e.g. U6 and pre-tRNAs) ceases. Other RNA polymerase III products such as the cellular Ro RNAs continue to be transcribed and assembled into ribonucleoprotein complexes containing the Ro (SS-A) antigens. Using a 32P-pulse chase-labeled, adenovirus-infected HeLa cellular extract as a source of antigen, anti-La (SS-B) and anti-Ro (SS-A) antibodies can be detected simultaneously using an immunoprecipitation assay. In the present study this method was found to be more sensitive in detecting anti-La antibodies then counter immunoelectrophoresis and immunoblotting. In studies of sera from patients suffering from rheumatic diseases the percentage positive for anti-La antibody was significantly elevated using this method, especially in patients with systemic lupus erythematosus.

Adenoviruses, Human↗
PubMed1990

Possible association between anti-Ro antibodies and myocarditis or cardiac conduction defects in adults with systemic lupus erythematosus.

In view of the association of congenital heart block with maternal antibody to cellular antigen Ro (SSA), and one report linking anti-Ro with myocarditis in a patient with myositis an association between anti-Ro antibodies and cardiac disease was sought in adults with systemic lupus erythematosus (SLE). Among 67 patients with SLE, of whom 36 were anti-Ro positive, a significantly higher prevalence of myocarditis and conduction defects was found in the anti-Ro positive group (eight of 36) than in those who were anti-Ro negative (one of 31) and healthy controls (one of 50). Of the 36 anti-Ro positive patients with SLE, three had symptoms diagnostic of myocarditis, and an electrocardiogram showed first degree atrioventricular block and unifascicular block in three cases (including one with myocarditis), right bundle branch block alone (two cases), and first degree atrioventricular block alone (one case). Complete atrioventricular block was not seen. In the anti-Ro negative group there was no myocarditis and only one case of conduction defect (right bundle branch block). Among healthy controls only one of 50 had first degree atrioventricular block. It is concluded that myocarditis and conduction defects are reasonably common in adults with SLE and are associated with anti-Ro antibodies.

Adolescent↗
PubMed1988

The significance of some immunoserologic diagnostic tests in systemic diseases.

The sensitivity and specificity of immunoserologic tests included in the diagnostic criteria of systemic lupus erythematosus are shown. The frequencies of some rare autoantibodies (PCNA, PL-4, SL, PM-Scl, Scl-70, Jo-1) in systemic connective tissue diseases of mixed Yugoslav population are demonstrated. The results from different laboratories differ considerably and the possible reasons are described.

Antibodies, Antinuclear↗
PubMedDate not supplied

Fluctuation of anti-Ro/SS-A antibody levels in patients with systemic lupus erythematosus and Sjögren's syndrome: a prospective study.

OBJECTIVE: To determine whether the titers of anti-Ro/SS-A (Ro) antibodies fluctuate during the course of SLE and Sjögren's syndrome (SS) in parallel with disease activity, and if such fluctuations could be used to predict disease flares. We also evaluated whether the anti-Ro profile (anti-Ro 52, anti-Ro 60) changes over time, since such information could provide new insights into the induction and regulation of anti-Ro autoimmunity. METHODS: Sixteen patients with SLE and 15 patients with SS, all anti-Ro/SS-A antibody positive, were followed up for two years at three-month intervals. Clinical and laboratory parameters of disease activity were examined. Determination of the anti-Ro/SS-A titer was performed by counterimmunoelectrophoresis and the fine anti-Ro antibody specificity was determined by immunoblotting. RESULTS: The titers of anti-Ro antibodies fluctuated during the course of the illness in both SLE and SS patients. In SLE patients these changes were not (except in one case) associated with disease activity nor were they predictive of disease flares. The same was true for the SS patients, with the exception of two patients with skin vasculitis in whom anti-Ro antibody titers fluctuated in parallel with the disease activity. The anti-Ro antibody (anti-Ro 60 kD, anti-Ro 52 kD) specificity did not change in any of the patients during the follow-up period. CONCLUSION: Anti-Ro antibodies could represent a valuable indicator of disease activity in SS patients with cutaneous disorders. They do not, on the other hand, reflect disease activity in patients with SLE. The stable antibody profile in both SLE and SS patients supports the hypothesis that autoantibody production is predominantly genetically regulated.

Adolescent↗
PubMedDate not supplied

Estimation of anticardiolipin antibodies, anti-beta2 glycoprotein I antibodies and lupus anticoagulant in a prospective longitudinal study of children with juvenile idiopathic arthritis.

OBJECTIVE: Anticardiolipin antibodies (aCL) have been frequently detected in juvenile idiopathic arthritis (JIA), but have not been associated with disease activity or clinical features of the antiphospholipid syndrome (APS). Our aim was to determine aCL and anti-beta2 glycoprotein I (anti-beta2GPI) antibody levels and lupus anticoagulant (LA) in serial samples from children with JIA and to investigate the clinical significance of these antibodies. METHODS: The values of aCL, anti-beta2GPI and LA were prospectively followed in 28 children with JIA from disease onset. aCL and anti-beta2GPI were assayed by an ELISA method. Two monoclonal beta2GPI-dependent aCL (HCAL and EY2C9) were used as calibrators. LA was determined by a modified dilute Russell viper venom time test. RESULTS: Thirteen (46.4%) children with JIA were already positive for aCL at their first referral to our center. During the follow-up, the frequency of aCL decreased from 46.4% to 28.6%; however, it remained significantly higher compared with healthy children. In contrast, for anti-beta2GPI the difference in the frequency between the children with JIA and healthy children was not statistically significant. Serial determination of aPL levels in JIA patients revealed frequent fluctuations. Positive aCL persisted over time in 6 (21.4%) children with JIA, 6 (21.4%) children were initially positive for aCL, but became later negative, and 3 (10.7%) children were initially negative for aCL and became later positive. Persistently positive anti-beta2GPI were observed during the follow-up only in one patient, while none of the patients was persistently positive for LA. No association between aCL, anti-beta2GPI or LA and disease activity could be established. No patient with positive aCL, anti-beta2GPI or LA showed any clinical feature of APS. CONCLUSION: The discrepancy between the presence of aCL and anti-beta2GPI might indicate that the production of aCL in JIA is associated with an infectious trigger. Furthermore, the low frequency of anti-beta2GPI and LA could explain the limited prothrombotic potential of aPL observed in JIA. However, we found a distinct group of JIA patients with persistently positive aCL, the clinical implications of which are at the present time unknown.

Adolescent↗