Karl Egerer

Rheumatoid factor revisited.

Purpose of reviewInitial studies of the pathogenesis of rheumatoid arthritis focused on the role of rheumatoid factor and immune complex–associated vasculitis and synovitis. Subsequent work has delineated T cell responses, the role of cytokines, chemokines, and the aggressive nature of rheumatoid synovitis. Recent findings underscore the importance of humoral immunity in this entity and are the subject of this review. Recent findingsBy the discovery of anti–cyclic citrullinated peptide, anti-RA33, and anti-GPI antibodies in the human and mouse systems, respectively, the impact of humoral autoimmunity in rheumatoid arthritis regained remarkable interest. This review summarizes recent insights into humoral autoimmunity in rheumatoid arthritis in the context of the generation of rheumatoid factors, including B cell activation via toll-like receptors and genetic predispositions that can trigger the induction of rheumatoid arthritis. The generation of rheumatoid factors that can also be found during host defense against infectious agents and under pathologic conditions, such as rheumatoid arthritis, Sjögren syndrome, and hepatitis C–associated mixed cryoglobulinemia after hepatitis C infection is likely the result of genetic predispositions and the intensity of the (primary) immune reaction. Models of the role of rheumatoid factors in health and disease, including related lymphomagenesis, will be discussed. SummaryIn patients with rheumatoid arthritis, the induction of rheumatoid factors can be taken as an indicator of severe disease with a striking involvement of B cell activation. Very recent clinical trials using B cell depletion support the concept that humoral immunity, as evidenced by the production of rheumatoid factors, plays a significant role in the course of the disease.

Induction therapy with adalimumab plus methotrexate for 24 weeks followed by methotrexate monotherapy up to week 48 versus methotrexate therapy alone for DMARD-naïve patients with early rheumatoid arthritis: HIT HARD, an investigator-initiated study

Objective To investigate the long-term effects of induction therapy with adalimumab (ADA) plus methotrexate (MTX) in comparison with placebo (PBO) plus MTX in DMARD-naïve patients with active early rheumatoid arthritis (RA). Methods Patients with active early RA (disease duration of ≤12 months) were randomly assigned to receive 40 mg ADA subcutaneously every other week (eow) plus MTX 15 mg/week subcutaneously or PBO plus MTX subcutaneously at 15 mg/week over 24 weeks. Thereafter, all patients received MTX monotherapy up to week 48. The primary outcome was the Disease Activity Score 28 (DAS28) at week 48. Secondary outcomes included proportions of patients in remission (DAS28<2.6), ACR responses, Health Assessment Questionnaire (HAQ) score and radiographic progression. Results 87 patients were assigned to ADA/MTX and 85 patients to PBO/MTX. At baseline, DAS28 was 6.2±0.8 in the ADA/MTX and 6.3±0.9 in the PBO/MTX groups. At week 24, treatment with ADA/MTX compared with PBO/MTX resulted in a greater reduction in DAS28 (3.0±1.2 vs 3.6±1.4; p=0.009) and other secondary outcomes such as DAS28 remission rate (47.9% vs 29.5%; p=0.021) and HAQ (0.49±0.6 vs 0.72±0.6; p=0.0014). At week 48, the difference in clinical outcomes between groups was not statistically significant (DAS28: 3.2±1.4 vs 3.4±1.6; p=0.41). Radiographic progression at week 48 was significantly greater in patients administered PBO/MTX (Sharp/van der Heijde score: ADA/MTX 2.6 vs PBO/MTX 6.4; p=0.03, Ratingen score: 1.7 vs 4.2; p=0.01). Conclusions A greater reduction in radiographic progression after initial combination therapy with ADA and MTX was seen at week 48, even after discontinuation of ADA treatment at week 24. This sustained effect was not found at the primary endpoint (DAS28 reduction).

Hyperprocalcitonemia in patients with noninfectious SIRS and pulmonary dysfunction associated with cardiopulmonary bypass

Background The incidence of noninfectious systemic inflammatory response syndrome (SIRS) associated with coronary artery bypass surgery and the potential role of several inflammatory parameters as early markers of pulmonary dysfunction induced by cardiopulmonary bypass (CPB) were investigated. Methods Forty patients undergoing elective coronary artery bypass surgery were studied prospectively. Perioperative lung function was monitored using the lung injury score introduced by Murray and colleagues, by measuring venous admixture (Qs/Qt), and, in some cases, by measuring extravascular lung water. Serum concentrations of the inflammatory parameters (procalcitonin, interleukin‐6, sL‐selectin, leukocyte elastase, neopterin, leukocyte counts, and C‐reactive protein) were determined sequentially. The American College of Chest Physicians‐Society of Critical Care Medicine classification system was used to diagnose SIRS. Results According to the entry criteria, SIRS developed in 17 (42%) patients after operation. Nine patients of this group showed signs of acute pulmonary impairment, whereas patients without SIRS had no lung injury. In all patients with acute lung injury, distinct increases in procalcitonin concentrations ranging from 5.1 to 14.3 ng/ml were measured. In patients with SIRS but without acute lung injury and in patients without SIRS, none or only negligible increases in serum concentrations of procalcitonin were seen. Compared with procalcitonin, other inflammatory parameters investigated were less sensitive and less specific to indicate pulmonary dysfunction secondary to CPB. Conclusions Procalcitonin seems to be an appropriate parameter indicating the early development of severe noninfectious SIRS and for predicting pulmonary dysfunction secondary to CPB.

Automated evaluation of autoantibodies on human epithelial-2 cells as an approach to standardize cell-based immunofluorescence tests

IntroductionAnalysis of autoantibodies (AAB) by indirect immunofluorescence (IIF) is a basic tool for the serological diagnosis of systemic rheumatic disorders. Automation of autoantibody IIF reading including pattern recognition may improve intra- and inter-laboratory variability and meet the demand for cost-effective assessment of large numbers of samples. Comparing automated and visual interpretation, the usefulness for routine laboratory diagnostics was investigated.MethodsAutoantibody detection by IIF on human epithelial-2 (HEp-2) cells was conducted in a total of 1222 consecutive sera of patients with suspected systemic rheumatic diseases from a university routine laboratory (n = 924) and a private referral laboratory (n = 298). IIF results from routine diagnostics were compared with a novel automated interpretation system.ResultsBoth diagnostic procedures showed a very good agreement in detecting AAB (kappa = 0.828) and differentiating respective immunofluorescence patterns. Only 98 (8.0%) of 1222 sera demonstrated discrepant results in the differentiation of positive from negative samples. The contingency coefficients of chi-square statistics were 0.646 for the university laboratory cohort with an agreement of 93.0% and 0.695 for the private laboratory cohort with an agreement of 90.6%, P < 0.0001, respectively. Comparing immunofluorescence patterns, 111 (15.3%) sera yielded differing results.ConclusionsAutomated assessment of AAB by IIF on HEp-2 cells using an automated interpretation system is a reliable and robust method for positive/negative differentiation. Employing novel mathematical algorithms, automated interpretation provides reproducible detection of specific immunofluorescence patterns on HEp-2 cells. Automated interpretation can reduce drawbacks of IIF for AAB detection in routine diagnostics providing more reliable data for clinicians.

Insulin resistance in moderate chronic heart failure is related to hyperleptinaemia, but not to norepinephrine or TNF-alpha.

OBJECTIVES Chronic heart failure (CHF) has emerged as an insulin-resistant state, independently of ischaemic aetiology. The underlying mechanisms of this finding are not known. Catecholamines, tumor necrosis factor alpha (TNFalpha) and leptin, the adipocyte specific hormone, have all been implicated as mediators of impaired insulin sensitivity. The purpose of this study was to examine in patients with CHF and in comparison to healthy controls subjects whether norepinephrine, TNFalpha or leptin relate to insulin sensitivity. DESIGN 41 patients with CHF (age 60+/-2 years, NYHA I/II/III/IV 4/12/22/3, peak oxygen consumption 17.6+/-1.0 ml/kg per min) and 21 healthy controls of similar age and total and regional fat distribution were studied in a cross-sectional study. Insulin sensitivity was assessed by intravenous glucose tolerance testing using the minimal model approach; catecholamines, TNFalpha and soluble TNF receptors 1 and 2 were also measured. Total and regional body fat mass was assessed by dual energy X-ray absorptiometry. RESULTS Insulin sensitivity was reduced in CHF patients compared to controls by 31% (P<0.01) and fasting insulin was higher in patients than in controls (79.1+/-9.7 vs. 41.4+/-6.0 pmol/l, P<0.01). Patients had, compared to healthy controls, elevated serum leptin levels (8.28+/-0.84 vs. 4.83+/-0.68 ng/ml), norepinephrine (3.45+/-0.34 vs. 1.87+/-0.16 nmol/l, both P<0.01) and soluble TNF-receptors 1 (1280+/-141 vs. 639+/-52 pg/ml) and 2 (2605+/-184 vs. 1758+/-221 pg/ml, both P<0.01). Leptin levels corrected for total body fat mass were higher in CHF patients than in controls (41.3+/-3 vs. 24.3+/-2 pg/ml per 100 g, P<0.001). TNFalpha was not significantly different between the groups. In both groups there was an inverse correlation between insulin sensitivity and serum leptin (r=-0.65, P<0.0001 for pooled subjects); in contrast, no significant relation was found between insulin sensitivity and norepinephrine or TNFalpha. In multivariate regression analysis, leptin emerged as the only significant predictor of insulin sensitivity (standardised coefficient=-0.59, P<0.001), independent of body fat mass, age and peak VO2. CONCLUSION In moderate CHF, elevated leptin levels directly and independently predict insulin resistance. Elevated serum leptin levels could play a role in the impaired regulation of energy metabolism in CHF. In contrast to observations in other conditions, TNFalpha and norepinephrine are not related to insulin resistance in moderate CHF.

Diagnostic value of anti-topoisomerase I antibodies in a large monocentric cohort

IntroductionIn the present study, the detection of anti-topoisomerase I (anti-topo I) autoantibodies was evaluated for diagnosis and risk assessment of systemic sclerosis (SSc) patients in a well characterized large monocentric cohort.MethodsSera from patients with SSc (diffuse n = 96, limited n = 113), from patients with overlap syndromes (n = 51), from patients with other diseases associated with SSc (n = 20), as well as from disease controls (n = 487) were analysed for the presence of anti-topo I antibodies by line immunoblot assay and ELISA. Assessment of organ manifestations was performed as proposed by the European Scleroderma Trial and Research network.ResultsThe applied test systems for the detection of anti-topo I antibodies revealed a diagnostic sensitivity for SSc of approximately 24% and a diagnostic specificity of at least 99.6%. The sensitivity to identify patients with diffuse SSc amounted to 60%. Patients with anti-topo I antibodies showed a higher burden of skin and lung fibrosis, contractures, electrocardiogram changes, as well as digital ulcers and had more active disease than antibody-negative patients. Signal strengths correlated only weakly with disease activity, with modified Rodnan skin score, with predicted forced vital capacity, and with predicted diffusion capacity levels (P = 0.01, ρ = 0.234, ρ = 0.413, ρ = -0.215, ρ = -0.219). High signal intensities were associated with an increased mortality in diffuse SSc patients (P = 0.003).ConclusionsDiagnosis and risk assessment of SSc patients can be supported by the detection of anti-topo I antibodies. Signal intensities as obtained by line immunoblot assay or ELISA can be used as a surrogate marker for fibrosis, active disease and worse prognosis.

Anti-dsDNA-NcX ELISA: dsDNA-loaded nucleosomes improve diagnosis and monitoring of disease activity in systemic lupus erythematosus

IntroductionThe objective of this study was to compare the clinical usefulness of the new anti-double-stranded DNA nucleosome-complexed enzyme-linked immunosorbent assay (Anti-dsDNA-NcX ELISA), which is based on dsDNA-loaded nucleosomes as antigens, with established test systems based on dsDNA or nucleosomes alone for systemic lupus erythematosus (SLE) diagnostics and determination of disease activity.MethodsSera from a cohort of 964 individuals comprising 207 SLE patients, 357 disease controls and 400 healthy donors were investigated using the Anti-dsDNA-NcX ELISA, Farr assay, Anti-dsDNA ELISA, Anti-nucleosome ELISA and Crithidia luciliae immunofluorescence (CLIF) assay, all of which are tests available from EUROIMMUN Medizinische Labordiagnostika AG (Lübeck, Germany). Receiver operating characteristic curve analyses were performed to compare the sensitivity and specificity of each assay. The test results yielded by these assays in a group of 165 fully characterized SLE patients were compared with the corresponding medical records.ResultsThe Anti-dsDNA-NcX ELISA was found to have a sensitivity of 60.9% and a specificity of 98.9% in all 964 individuals at the manufacturers cutoff of 100 U/ml. At a comparable specificity of 99%, the sensitivity amounted to 59.9% for the Anti-dsDNA-NcX ELISA, 54.1% for the Farr assay, 53.6% for the antinucleosome ELISA and 35.8% for the anti-dsDNA ELISA. The CLIF assay had a sensitivity of 28.0% and a specificity of 98.2%. The Anti-dsDNA-NcX ELISA correlated mostly with global disease activity in a cross-sectional analysis. In a longitudinal analysis of 20 patients with 69 patient visits, changes in Anti-dsDNA-NcX ELISA and antinucleosome ELISA results correlated highly with changes in disease activity over time.ConclusionsThe use of dsDNA-complexed nucleosomes as antigens in ELISA leads to optimized determination of diagnosis and disease activity in SLE patients and is available for clinical practice.

Influence of peptidylarginine deiminase type 4 genotype and shared epitope on clinical characteristics and autoantibody profile of rheumatoid arthritis

Background: Recent evidence suggests that distinction of subsets of rheumatoid arthritis (RA) depending on anti-cyclic citrullinated peptide antibody (anti-CCP) status may be helpful in distinguishing distinct aetiopathologies and in predicting the course of disease. HLA-DRB1 shared epitope (SE) and peptidylarginine deiminase type 4 (PADI4) genotype, both of which have been implicated in anti-CCP generation, are assumed to be associated with RA. Objectives: To elucidate whether PADI4 affects the clinical characteristics of RA, and whether it would modulate the effect of anti-CCPs on clinical course. The combined effect of SE and PADI4 on autoantibody profile was also analysed. Methods: 373 patients with RA were studied. SE, padi4_94C>T, rheumatoid factor, anti-CCPs and antinuclear antibodies (ANAs) were determined. Disease severity was characterised by cumulative therapy intensity classified into ordinal categories (CTI-1 to CTI-3) and by Steinbrocker score. Results: CTI was significantly associated with disease duration, erosive disease, disease activity score (DAS) 28 and anti-CCPs. The association of anti-CCPs with CTI was considerably influenced by padi4_94C>T genotype (C/C: ORadj = 0.93, padj = 0.92; C/T: ORadj = 2.92, padj = 0.093; T/T: ORadj = 15.3, padj = 0.002). Carriage of padi4_94T exhibited a significant trend towards higher Steinbrocker scores in univariate and multivariate analyses. An association of padi4_94C>T with ANAs was observed, with noteworthy differences depending on SE status (SE−: ORadj = 6.20, padj<0.04; SE+: ORadj = 0.36, padj = 0.02) and significant heterogeneity between the two SE strata (p = 0.006). Conclusions: PADI4 genotype in combination with anti-CCPs and SE modulates clinical and serological characteristics of RA.

Antiphospholipid antibody profiling: time for a new technical approach?

Detection of anti-phospholipid (aPL) antibodies for state-of-the art diagnosis of antiphospholipid syndrome(APS) still remains a laboratory challenge due to the great diversity of aPL antibodies and their relevance with regard to the diagnostic criteria. According to the recently revised classification criteria for APS, several enzyme-linked immunosorbent assays (ELISAs) should be performed simultaneously in routine laboratories for the detection of aPL antibodies. Therefore, new approaches to aPL profiling have been proposed recently to provide information regarding diagnosis and eventually outcome in APS patients. Multiplex analysis could meet the increasing demand for cost-efficient detection and profiling of aPL antibodies. Multi-line immunodot assays or bead-based multiplex techniques candidate as alternatives to assess several aPL antibodies simultaneously employing different solid-phases for bound/free separation of reactants. Particularly, multi-line immunodot assays present an alternative to ELISA for aPL antibody detection and profiling in APS patients. The use of hydrophobic membranes as solid-surface by this technique appears to offer a distinct solid-phase reaction environment for the assessment of aPL antibodies. This article reviews novel developments in the field of laboratory diagnostics of APS with special emphasis on multiplex assays.

Clinical and serological evaluation of a novel CENP-A peptide based ELISA

IntroductionAnti-centromere antibodies (ACA) are useful biomarkers in the diagnosis of systemic sclerosis (SSc). ACA are found in 20 to 40% of SSc patients and, albeit with lower prevalence, in patients with other systemic autoimmune rheumatic diseases. Historically, ACA were detected by indirect immunofluorescence (IIF) on HEp-2 cells and confirmed by immunoassays using recombinant CENP-B. The objective of this study was to evaluate a novel CENP-A peptide ELISA.MethodsSera collected from SSc patients (n = 334) and various other diseases (n = 619) and from healthy controls (n = 175) were tested for anti-CENP-A antibodies by the novel CENP-A enzyme linked immunosorbent assay (ELISA). Furthermore, ACA were determined in the disease cohorts by IIF (ImmunoConcepts, Sacramento, CA, USA), CENP-B ELISA (Dr. Fooke), EliA® CENP (Phadia, Freiburg, Germany) and line-immunoassay (LIA, Mikrogen, Neuried, Germany). Serological and clinical associations of anti-CENP-A with other autoantibodies were conducted in one participating centre. Inhibition experiments with either the CENP-A peptide or recombinant CENP-B were carried out to analyse the specificity of anti-CENP-A and -B antibodies.ResultsThe CENP-A ELISA results were in good agreement with other ACA detection methods. According to the kappa method, the qualitative agreements were: 0.73 (vs. IIF), 0.81 (vs. LIA), 0.86 (vs. CENP-B ELISA) and 0.97 (vs. EliA® CENP). The quantitative comparison between CENP-A and CENP-B ELISA using 265 samples revealed a correlation value of rho = 0.5 (by Spearman equation). The receiver operating characteristic analysis indicated that the discrimination between SSc patients (n = 131) and various controls (n = 134) was significantly better using the CENP-A as compared to CENP-B ELISA (P < 0.0001). Modified Rodnan skin score was significantly lower in the CENP-A negative group compared to the positive patients (P = 0.013). Inhibition experiments revealed no significant cross reactivity of anti-CENP-A and anti-CENP-B antibodies. Statistically relevant differences for gender ratio (P = 0.0103), specific joint involvement (Jaccoud) (P = 0.0006) and anti-phospholipid syndrome (P = 0.0157) between ACA positive SLE patients and the entire SLE cohort were observed.ConclusionsAnti-CENP-A antibodies as determined by peptide ELISA represent a sensitive, specific and independent marker for the detection of ACA and are useful biomarkers for the diagnosis of SSc. Our data suggest that anti-CENP-A antibodies are a more specific biomarker for SSc than antibodies to CENP-B. Furthers studies are required to verify these findings.