BackgroundThe Kato-Katz is the most common diagnostic method for Schistosoma mansoni infection. However, the day-to-day variability in host egg-excretion and its low detection sensitivity are major limits for its use in low transmission zones and after widespread chemotherapy. We evaluated the accuracy of circulating cathodic antigen (CCA) urine-assay as a diagnostic tool of S. mansoni. In comparison, a low sensitive CCA test (CCA-L) was assessed.MethodologyThe study was conducted in three settings: two foci with single S. mansoni infections (settings A and B), and one mixed S. mansoni – S. haematobium focus (setting C). Stool and urine samples were collected from school-children on three consecutive days. Triplicate Kato-Katz readings were performed per stool sample. Each urine sample was tested with one CCA and only the first urine sample was subjected to CCA-L. Urine samples were also examined for S. haematobium eggs using the filtration method and for microhaematuria using urine reagent strips. Overall, 625 children provided three stool and three urine samples.Principal FindingsConsidering nine Kato-Katz thick smears as ‘reference’ diagnostic test, the prevalence of S. mansoni was 36.2%, 71.8% and 64.0% in settings A, B and C, respectively. The prevalence of S. haematobium in setting C was 12.0%. The sensitivities of single Kato-Katz, CCA and CCA-L from the first stool or urine samples were 58%, 82% and 46% in setting A, 56.8%, 82.4% and 68.8% in setting B, and 49.0%, 87.7% and 55.5% in setting C. The respective specificities were 100%, 64.7% and 100%; 100%, 62.3% and 91.3%; and 100%, 42.5% and 92.0%. Mixed infection with S. haematobium did not influence the CCA test results for S. mansoni diagnosis.Conclusions/SignificanceUrine CCA revealed higher sensitivity than CCA-L and triplicate Kato-Katz, and produced similar prevalence as nine Kato-Katz. It seems an attractive method for S. mansoni diagnosis.

Aims Natriuretic peptides are extensively studied biomarkers for atrial fibrillation (AF) and heart failure (HF). Their role in the pathogenesis of both diseases is not entirely understood and previous studies several single-nucleotide polymorphisms (SNPs) at the NPPA-NPPB locus associated with natriuretic peptides have been identified. We investigated the causal relationship between natriuretic peptides and AF as well as HF using a Mendelian randomization approach. Methods and results N-terminal pro B-type natriuretic peptide (NT-proBNP) (N = 6669), B-type natriuretic peptide (BNP) (N = 6674), and mid-regional pro atrial natriuretic peptide (MR-proANP) (N = 6813) were measured in the FINRISK 1997 cohort. N = 30 common SNPs related to NT-proBNP, BNP, and MR-proANP were selected from studies. We performed six Mendelian randomizations for all three natriuretic peptide biomarkers and for both outcomes, AF and HF, separately. Polygenic risk scores (PRSs) based on multiple SNPs were used as genetic instrumental variable in Mendelian randomizations. Polygenic risk scores were significantly associated with the three natriuretic peptides. Polygenic risk scores were not significantly associated with incident AF nor HF. Most cardiovascular risk factors showed significant confounding percentages, but no association with PRS. A causal relation except for small causal betas is unlikely. Conclusion In our Mendelian randomization approach, we confirmed an association between common genetic variation at the NPPA-NPPB locus and natriuretic peptides. A strong causal relationship between natriuretic peptides and incidence of AF as well as HF at the community-level was ruled out. Therapeutic approaches targeting natriuretic peptides will therefore very likely work through indirect mechanisms.

Background:The morbidity and mortality of systemic sclerosis (SSc) are largely determined by vascular and fibrotic pathologies. Levels of autoantibodies (ab) against G protein-coupled receptors (GPCR), growth factors (GF) and growth factor receptors (GFR) are altered in SSc compared to healthy controls (HC) 1. Thus, higher angiotensin II receptor type 1 - (AT1R) and endothelin receptor type A - (ETAR) ab levels are associated with severe disease and SSc-related mortality 2. CXC motiv chemokine receptor 3 - (CXCR3) and 4 - (CXCR4) ab have predictive value for deterioration of pulmonary fibrosis (PF) 3.Objectives:We used statistical methods to identify associations between disease manifestations and 28 new ab directed against GPCR, GF and GFR in SSc.Methods:Ab against the following targets were measured in sera from SSc patients (n = 177) and HC (n = 88): Adrenoceptors alpha-1 (ADRA1), alpha-2 (ADRA2), beta-1 (ADRB1), beta-2 (ADRB2); muscarinoceptors 1-5 (M1R - M5R); AT1R, ETAR, endothelin B receptor (ETBR); CXCR3, CXCR4; complement receptors 3a (C3aR) and 5a (C5aR); protease-activated receptors 1 (PAR1) and 2 (PAR2); vascular endothelial growth factor A (VEGFA) and its receptors 1 (VEGFR1) and 2 (VEGFR2), epithelial growth factor (EGF)/ - receptor (EGFR); hepatocyte growth factor (HGF)/ - receptor (HGFR), platelet-derived growth factor-AA (PDGFAA), placental growth factor (PlGF).The organ involvement (PF, cardiac involvement, PAH, gastrointestinal tract) and quantitative markers (modified Rodnan skin score, SSc activity score, pulmonary function, cardiac enzymes and echocardiography, routine laboratory, autoimmune diagnostics) as well as demographic data were recorded retrospectively at the time of sample collection. Statistical analysis was performed using the Mann-Whitney U test (MWU), Pearson correlations, ROC analysis, and age-adjusted logistic regression models.Results:In SSc 20 of 28 measured ab levels are significantly altered compared to HC. According to the Pearson correlation matrix, the ab-levels are highly correlated and build a network that differs between HC and SSc. Furthermore, altered network signatures are formed in the differentiated analysis of several disease manifestations of SSc such as SSc-subtype or PF. Based on ROC analysis, FGF-ab, ADRB1-ab and PlGF-ab are well suited to predict SSc (Figure 1).In addition, limited cutaneous SSc (lSSc) patients displayed lower levels of most ab than diffuse cutaneous SSc patients, whereas cardiac and pulmonary involvement are associated with higher ab levels. In the logistic regression lSSc is associated with lower levels of ab against M1R, M2R, C5aR, ETAR, AT1R, PAR1, EGFR. Higher levels for ab against M1R, M2R, ETBR, C5aR are associated with PF, higher levels of ab against complement receptors, adrenoreceptors and EGF with NT-proBNP elevation.Conclusion:The newly described antibodies against GPCR, GF and GFR are highly correlated. Associations with morbidity- and mortality-determining organ involvement indicate their possible functional relevance and novel pathophysiological mechanisms. As new biomarkers, some of the ab have prognostic value for SSc; for other manifestations, their value should be evaluated in further studies.References:[1]Cabral-Marques, O., Marques, A., Giil, L.M. et al. GPCR-specific autoantibody signatures are associated with physiological and pathological immune homeostasis. Nat Commun9, 5224 (2018). https://doi.org/10.1038/s41467-018-07598-9[2]Riemekasten G, Philippe A, Näther M, et al. Involvement of functional autoantibodies against vascular receptors in systemic sclerosis Annals of the Rheumatic Diseases 2011;70:530-536.[3]Weigold, F., Günther, J., Pfeiffenberger, M. et al. Antibodies against chemokine receptors CXCR3 and CXCR4 predict progressive deterioration of lung function in patients with systemic sclerosis. Arthritis Res Ther 20, 52 (2018). https://doi.org/10.1186/s13075-018-1545-8Disclosure of Interests:Kristina Sterner: None declared, Césaire J. K. Fouodo: None declared, Inke König: None declared, Axel Künstner: None declared, Hauke Busch: None declared, Harald Heidecke Shareholder of: Owner of CellTrend, Anja Schumann: None declared, Antje Müller: None declared, Gabriela Riemekasten: None declared, Susanne Schinke Grant/research support from: UCB sponsors EULAR registration fees

BackgroundSystemic sclerosis (SSc) is a rare autoimmune multisystemic disease with a significant disease burden and impact on life quality and survival. Disease specific, diagnostic and prognostic antibodies (ab) are known such as Scl70 and centromer (ACA) ab1 or recently endothelin or angiotensin receptors.2 Functional ab can bind G protein-coupled receptors (GPCR) regulating immune function and were reported in the pathogenesis of various inflammatory and non-inflammatory diseases.3 ObjectivesWe analysed 31 ab against GPCRs and growth factors in a retrospective cohort of 71 SSc patients compared to 196 sera from healthy controls (HC). Ab levels were related to disease manifestations such as sex, age, SSc phenotype in order to hypothesise functional ab and new pathogenic targets in SSc.MethodsThe retrospective clinical characterisation of 14 male and 57 female SSc patients (26–82 years) included mRSS, organ involvement assessed by laboratory tests, spirometry and imaging such as CT-scan or echocardiography. 30/71 had active disease (EUSTAR activity score). Ab were measured by ELISA and normalised to a standard serum. Median ab levels from SSc were compared to HC (Mann Whitney Test). Ab patterns were analysed using different statistical approaches (factor analysis, principal component analysis (PCA), linear discriminant analysis (LDA), cluster analysis and biserial correlation.ResultsClinical SSc subgroups (diffuse/limited cutaneous, male/female) differ in ab levels and form separate clusters (LDA method). Moreover, 5 resp. 7 latent factors group ab and clinical disease manifestations. Factor analysis reveals VEGFR2 and YBX1 ab to be more unique with the lowest communalities. The biserial correlation shows moderate associations between ab patterns and SSc specific symptoms such as Raynaud’s, calcinosis or akroosteolysis but also unspecific symptoms such as polyneuropathy. Compared to association of ETAR ab with Raynaud’s and skin sclerosis HGFR ab are inversely correlated. In HC most ab levels against GPCR and growth factors are higher than in SSc except for YBX1 which has the highest ab levels in SSc patients. In HC ab levels against YBX1 ab are associated with male sex and family history of rheumatic diseases. Yet, ADRB2 ab are linked to the absence of GI symptoms or depression and ab against ENG, ETAR, PAR2, PAR1 with normal troponine levels (absence of heart involvement).Abstract OP0005 – Figure 1(a) Projection of individuals (points) and variables (arrows), representing the measured proteins, in the space of the two principle components. The almost perfect separation between controls (cyan) and cases (orange) is explained by higher protein levels for almost all proteins in the HD groups against lower values in the SSc group. By contrast, only the YBI_P18 protein presents a tendance to be higher in the SSc group and lower in the other group. M1 and betaladr proteins have lowest contributions for separing HG from SSc participiants. (b) Dandelion plot displays 5 latent factors the cluster antibodies against GPCR...

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BackgroundAutoantibodies (ab) against G protein-coupled receptors (GPCR), such as ab against angiotensin II receptor type 1 (AT1R), endothelin receptor type A (ETAR) or CXC chemokine receptor 3 and 4 (CXCR3/4) may contribute to the pathogenesis of systemic sclerosis (SSc) [1]. AT1R- and ETAR-ab are associated with SSc-related mortality and CXCR3/4- ab predict a deteriorating pulmonary fibrosis [2,3].ObjectivesWe aim to identify new ab targets and ab discriminating healthy controls (HC) from SSc patients or SSc clinical phenotypes, organ involvements and therapy.MethodsSerum ab levels against a panel of GPCR, GF and GFR were measured by ELISA in SSc (n=177) and compared to HC (n=88). Gender matched and age adjusted data were screened for univariate differences of ab levels in clinical phenotypes, explored for multivariate predictive performance of ab levels by a random-forest classifier and tested for differences of ab correlations.ResultsIn SSc ab levels against 19 targets were higher compared to HC. Abs against fibroblast growth factor-2 (FGF-2), beta-adrenergic receptor 1 (ADRB1), and placental growth factor (PIGF) discriminated best SSc patients from HC. Multivariate predictions supported the ranking value of FGF-2 and ADRB1-abs for SSc and abs against ADRB1/2, muscarinic receptor 1 (M1R) and alpha-adrenergic receptor 2 ADRA2 for diffuse cutaneous SSc (dSSc) versus limited cutaneous SSc (lSSc). Ab levels were denser and stronger correlated in SSc than in HC (figure 1), suggesting a disturbed regulation of ab with a prominent role of FGF-2-abs in SSc. Comparing dSSc to lSSc, dSSc showed higher ab levels and correlated with several disease characteristics, but the multivariate classification showed poor accuracy.Figure 1.Different univariate correlations between abs in HC and SSc. The correlations of the ab concentrations are generally increased in SSc compared to HC. Largest accumulated differences are found for ETAR, VEGFA, AT1R and EGFR as indicated by the covered degrees in the circle. Dark bands depict significant differences after FDR-correction (p<.05)ConclusionSSc is characterized by both quantitative and qualitative alterations in ab levels and ab correlations. This study reveals ab against FGF-2, ADRB1 and PIGF to be new biomarkers of SSc. Alterations within these ab correlation networks could help to identify pathways promoting SSc and its clinical manifestations.References[1]Cabral-Marques O et al. 2018. GPCR-specific autoantibody signatures are associated with physiological and pathological immune homeostasisNature Communications95224[2]Riemekasten G et al. 2011. Involvement of functional autoantibodies against vascular receptors in systemic sclerosisAnnals of the Rheumatic Diseases70530–6[3]Weigold F et al. Antibodies against chemokine receptors CXCR3 and CXCR4 predict progressive deterioration of lung function in patients with systemic sclerosis.Arthritis Res Ther20, 52AcknowledgementsWe thank G. Marschner for excellent technical assistance and Prof Goerg and his team from UKSH Campus Lübeck, bloodbank, for helping to acquire healthy blood donors.Disclosure of InterestsSusanne Schinke Grant/research support from: Abbvie, Kristina Sterner: None declared, Harald Heidecke Shareholder of: Celltrend Company, Hauke Busch: None declared, Axel Kuenstner: None declared, Imke König: None declared, Césaire J. K. Fouodo: None declared, Antje Müller: None declared, Sara Comduehr: None declared, Tanja Lange: None declared, Finn Lübber: None declared, Frieder Paulus: None declared, Hanna Grasshoff: None declared, Gabriela Riemekasten: None declared.

Background Natriuretic peptides are extensively studied biomarkers for atrial fibrillation (AF) and heart failure (HF). Their role in the pathogenesis of both diseases is not entirely understood and in previous studies several single nucleotide polymorphisms (SNPs) at the NPPA-NPPB locus associated with natriuretic peptides have been identified. Purpose We investigated whether a causal relationship exists between natriuretic peptides and AF as well as HF using a Mendelian randomization approach. Methods N-terminal pro B-type natriuretic peptide (NT-proBNP) (N=6669), B-type natriuretic peptide (BNP) (N=6674) and mid-regional pro atrial natriuretic peptide (MR-proANP) (N=6813) were measured in the FINRISK 1997 cohort. Thirty common SNPs related to NT-proBNP, BNP and MR-proANP were selected from prior studies. We performed six Mendelian randomizations for all three natriuretic peptide biomarkers and for both outcomes, AF and HF separately. Polygenic risk scores (PRS) based on multiple SNPs were used as the genetic instrumental variable in Mendelian randomizations. Results PRS were significantly associated with the three natriuretic peptides. PRS were not significantly associated with incident AF nor HF. Most cardiovascular risk factors showed significant confounding percentages, but no association with PRS. A causal relation, other than a weak one, is unlikely. Conclusion In our Mendelian randomization approach, based on common genetic variation at the NPPA-NPPB locus, associations of the common polymorphisms with natriuretic peptides and the protein biomarkers themselves with incident disease could be confirmed. A strong causal relationship between natriuretic peptides and incidence of AF as well as HF was ruled out. Therapeutic approaches targeting natriuretic peptides will therefore very likely work through indirect mechanisms. Comparison of hazard ratios Funding Acknowledgement Type of funding source: Public grant(s) – EU funding. Main funding source(s): European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme, German Ministry of Research and Education