| 1. |
- Almlöf, Jonas Carlsson, et al.
(författare)
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Whole-genome sequencing identifies complex contributions to genetic risk by variants in genes causing monogenic systemic lupus erythematosus
- 2019
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Ingår i: Human Genetics. - : SPRINGER. - 0340-6717 .- 1432-1203. ; 138:2, s. 141-150
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Tidskriftsartikel (refereegranskat)abstract
- Systemic lupus erythematosus (SLE, OMIM 152700) is a systemic autoimmune disease with a complex etiology. The mode of inheritance of the genetic risk beyond familial SLE cases is currently unknown. Additionally, the contribution of heterozygous variants in genes known to cause monogenic SLE is not fully understood. Whole-genome sequencing of DNA samples from 71 Swedish patients with SLE and their healthy biological parents was performed to investigate the general genetic risk of SLE using known SLE GWAS risk loci identified using the ImmunoChip, variants in genes associated to monogenic SLE, and the mode of inheritance of SLE risk alleles in these families. A random forest model for predicting genetic risk for SLE showed that the SLE risk variants were mainly inherited from one of the parents. In the 71 patients, we detected a significant enrichment of ultra-rare (0.1%) missense and nonsense mutations in 22 genes known to cause monogenic forms of SLE. We identified one previously reported homozygous nonsense mutation in the C1QC (Complement C1q C Chain) gene, which explains the immunodeficiency and severe SLE phenotype of that patient. We also identified seven ultra-rare, coding heterozygous variants in five genes (C1S, DNASE1L3, DNASE1, IFIH1, and RNASEH2A) involved in monogenic SLE. Our findings indicate a complex contribution to the overall genetic risk of SLE by rare variants in genes associated with monogenic forms of SLE. The rare variants were inherited from the other parent than the one who passed on the more common risk variants leading to an increased genetic burden for SLE in the child. Higher frequency SLE risk variants are mostly passed from one of the parents to the offspring affected with SLE. In contrast, the other parent, in seven cases, contributed heterozygous rare variants in genes associated with monogenic forms of SLE, suggesting a larger impact of rare variants in SLE than hitherto reported.
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| 2. |
- Appelgren, Daniel, et al.
(författare)
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Active NET formation in Libman–Sacks endocarditis without antiphospholipid antibodies : A dramatic onset of systemic lupus erythematosus
- 2018
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Ingår i: Autoimmunity. - : Informa UK Limited. - 0891-6934 .- 1607-842X. ; 51:6, s. 310-318
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Tidskriftsartikel (refereegranskat)abstract
- Although neutrophil extracellular traps (NETs) have been highlighted in several systemic inflammatory diseases, their clinical correlates and potential pathological role remain obscure. Herein, we describe a dramatic onset of systemic lupus erythematosus (SLE) with clear-cut pathogenic implications for neutrophils and NET formation in a young woman with cardiac (Libman–Sacks endocarditis) and central nervous system (psychosis and seizures) involvement. Despite extensive search, circulating antiphospholipid autoantibodies, a hallmark of Libman–Sacks endocarditis, could not be detected. Instead, we observed active NET formation in the tissue of the mitral valve, as well as in the circulation. Levels of NET remnants were significantly higher in serially obtained sera from the patient compared with sex-matched blood donors (p =.0011), and showed a non-significant but substantial correlation with blood neutrophil counts (r = 0.65, p =.16). The specific neutrophil elastase activity measured in serum seemed to be modulated by the provided immunosuppressive treatment. In addition, we found anti-Ro60/SSA antibodies in the cerebrospinal fluid of the patient but not NET remnants or increased elastase activity. This case illustrates that different disease mechanisms mediated via autoantibodies can occur simultaneously in SLE. NET formation with release of cytotoxic NET remnants is a candidate player in the pathogenesis of this non-canonical form of Libman–Sacks endocarditis occurring in the absence of traditional antiphospholipid autoantibodies. The case description includes longitudinal results with clinical follow-up data and a discussion of the potential roles of NETs in SLE.
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| 3. |
- Arkema, Elizabeth V, et al.
(författare)
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Case definitions in Swedish register data to identify systemic lupus erythematosus
- 2016
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Ingår i: BMJ Open. - : B M J Group. - 2044-6055. ; 6:1
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To develop and investigate the utility of several different case definitions for systemic lupus erythematosus (SLE) using national register data in Sweden.METHODS: The reference standard consisted of clinically confirmed SLE cases pooled from four major clinical centres in Sweden (n=929), and a sample of non-SLE comparators randomly selected from the National Population Register (n=24 267). Demographics, comorbidities, prescriptions and autoimmune disease family history were obtained from multiple registers and linked to the reference standard. We first used previously published SLE definitions to create algorithms for SLE. We also used modern data mining techniques (penalised least absolute shrinkage and selection operator logistic regression, elastic net regression and classification trees) to objectively create data-driven case definitions. Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were calculated for the case definitions identified.RESULTS: Defining SLE by using only hospitalisation data resulted in the lowest sensitivity (0.79). When SLE codes from the outpatient register were included, sensitivity and PPV increased (PPV between 0.97 and 0.98, sensitivity between 0.97 and 0.99). Addition of medication information did not greatly improve the algorithm's performance. The application of data mining methods did not yield different case definitions.CONCLUSIONS: The use of SLE International Classification of Diseases (ICD) codes in outpatient clinics increased the accuracy for identifying individuals with SLE using Swedish registry data. This study implies that it is possible to use ICD codes from national registers to create a cohort of individuals with SLE.
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| 4. |
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| 5. |
- Arkema, Elizabeth V., et al.
(författare)
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Stroke in systemic lupus erythematosus : a Swedish population-based cohort study
- 2017
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Ingår i: Annals of the Rheumatic Diseases. - : HighWire Press. - 0003-4967 .- 1468-2060. ; 76:9, s. 1544-1549
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To study the occurrence of ischaemic and haemorrhagic stroke in systemic lupus erythematosus (SLE) compared with the general population by age, sex and time since SLE diagnosis METHODS: Adults with incident SLE were identified from the Swedish National Patient Register (NPR, n=3390) and general population comparators from the Total Population Register were matched on age, sex and county (n=16730). Individuals were followed prospectively until first of death, December 2013, emigration or incident stroke (identified from the NPR, Cause of Death Register and the Stroke Register). Incidence rates, rate differences and HR were estimated comparing SLE with non-SLE. Estimates were stratified by sex, age and time since diagnosis.RESULTS: We observed 126 strokes in SLE and 304 in the general population. Individuals with SLE had a twofold increased rate of ischaemic stroke compared with the general population (HR 2.2; 95% CI 1.7 to 2.8). The HR for intracerebral haemorrhage was 1.4 (95% CI 0.7 to 2.8). There was effect modification by sex and age, with the highest HRs for females and individuals <50 years old. The HR for ischaemic stroke was highest in the first year of follow-up (3.7; 95% CI 2.1 to 6.5).CONCLUSIONS: The relative risk of ischaemic stroke in SLE was more than doubled compared with the general population, and importantly, the highest relative risks were observed within the first year after SLE diagnosis. Thus, the first encounter with patients presents an opportunity for rheumatologists to screen for risk factors and intervene.
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| 6. |
- Arkema, Elizabeth V, et al.
(författare)
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What to Expect When Expecting With Systemic Lupus Erythematosus (SLE) : A Population-Based Study of Maternal and Fetal Outcomes in SLE and Pre-SLE.
- 2016
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Ingår i: Arthritis care & research. - : Wiley-Blackwell. - 2151-464X .- 2151-4658. ; 68:7
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To assess maternal and fetal outcomes associated with subclinical (pre-systemic lupus erythematosus [SLE] and SLE presenting up to 5 years postpartum) and prevalent maternal SLE during pregnancy compared with the general population.METHODS: This prospective cohort study used population-based Swedish registers to identify 13,598 women with first singleton pregnancies registered in the Medical Birth Register (551 prevalent SLE, 65 pre-SLE within 0-2 years, 133 pre-SLE within 2-5 years, and 12,847 general population). SLE was defined as ≥2 SLE-coded discharge diagnoses in the patient register with ≥1 diagnosis from a specialist. Unadjusted risks of adverse pregnancy or birth outcomes were calculated by SLE status, and Cochran-Armitage tests evaluated trend across exposure groups.RESULTS: Maternal outcomes such as preeclampsia, hypothyroidism, stroke, and infection were more common among women with SLE. Sixteen percent of prevalent-SLE pregnancies were diagnosed with preeclampsia compared with 5% of those from the general population. Among the pre-SLE women, preeclampsia was found in 26% of those with SLE within 2 years postpartum and 13% in those with SLE within 2-5 years postpartum. Similarly, infant outcomes, such as preterm birth, infection, and mortality, were worse among those born to mothers with prevalent SLE and pre-SLE during pregnancy. The test for trend was significant for most outcomes.CONCLUSION: Our data demonstrate that adverse maternal and fetal outcomes are more common in SLE pregnancies. Furthermore, these unfavorable outcomes are observed in pregnancies occurring prior to the diagnosis of SLE. Thus, the underlying immunologic profile of SLE and alterations preceding clinical SLE may contribute to these pregnancy complications.
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| 7. |
- Bentow, C., et al.
(författare)
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International multi-center evaluation of a novel chemiluminescence assay for the detection of anti-dsDNA antibodies
- 2016
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Ingår i: Lupus. - : SAGE PUBLICATIONS LTD. - 0961-2033 .- 1477-0962. ; 25:8, s. 864-872
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Tidskriftsartikel (refereegranskat)abstract
- Objective: Anti-double stranded desoxyribonucleic acid (anti-dsDNA) antibodies are considered fairly specific for systemic lupus erythematosus (SLE) and their quantification is useful for the clinical management of SLE patients. We assessed the diagnostic performance of the QUANTA Flash dsDNA chemiluminescent immunoassay (CIA) in comparison to an ELISA, using patients from five participating countries. The main focus was to evaluate the correlation between anti-dsDNA antibody results from the CIA and global SLE disease activity, as measured by the SLE Disease Activity Index 2000 (SLEDAI-2K). Patients and methods: A total of 1431 samples (SLE, n=843; disease controls, n=588) from five countries (Canada, USA, Portugal, Sweden and Spain) were tested with QUANTA Flash dsDNA (Inova Diagnostics, San Diego, CA, USA). Data obtained with the QUANTA Lite dsDNA SC ELISA (Inova Diagnostics) were available for samples from three sites (Canada, USA and Sweden, n=566). The SLEDAI-2K scores were available for 805 SLE patients and a cut-off ofamp;gt;4 was used to define active disease. Results: QUANTA Flash dsDNA had a sensitivity of 54.3% for the diagnosis of SLE, combined with 89.8% specificity. Anti-dsDNA antibody levels were significantly higher (pamp;lt;0.0001) in active SLE (SLEDAI-2Kamp;gt;4; n=232; median value 83.0IU/mL) versus the inactive patients (n=573; median value 22.3IU/mL), and the SLEDAI-2K scoring correlated with their dsDNA antibody levels (Spearmans rho=0.44, pamp;lt;0.0001). Similar but less pronounced findings were also found for the ELISA, in relation to disease activity. Conclusions: The QUANTA Flash dsDNA assay showed good clinical performance in a large international multi-center study. Additionally, the strong correlation between anti-dsDNA antibody results and SLEDAI-2K scores supported the potential utility of QUANTA Flash dsDNA for monitoring disease activity.
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| 8. |
- Carlsson Almlöf, Jonas, et al.
(författare)
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Novel risk genes for systemic lupus erythematosus predicted by random forest classification
- 2017
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 7:1
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Tidskriftsartikel (refereegranskat)abstract
- Genome-wide association studies have identified risk loci for SLE, but a large proportion of the genetic contribution to SLE still remains unexplained. To detect novel risk genes, and to predict an individual's SLE risk we designed a random forest classifier using SNP genotype data generated on the "Immunochip" from 1,160 patients with SLE and 2,711 controls. Using gene importance scores defined by the random forest classifier, we identified 15 potential novel risk genes for SLE. Of them 12 are associated with other autoimmune diseases than SLE, whereas three genes (ZNF804A, CDK1, and MANF) have not previously been associated with autoimmunity. Random forest classification also allowed prediction of patients at risk for lupus nephritis with an area under the curve of 0.94. By allele-specific gene expression analysis we detected cis-regulatory SNPs that affect the expression levels of six of the top 40 genes designed by the random forest analysis, indicating a regulatory role for the identified risk variants. The 40 top genes from the prediction were overrepresented for differential expression in B and T cells according to RNA-sequencing of samples from five healthy donors, with more frequent over-expression in B cells compared to T cells.
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| 9. |
- Crisci, Elisa, et al.
(författare)
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Complement opsonization promotes HSV-2 infection of human dendritic cells
- 2016
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Ingår i: Journal of Virology. - : American society of microbiology. - 0022-538X .- 1098-5514. ; 90:10, s. 4939-4950
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Tidskriftsartikel (refereegranskat)abstract
- Herpes virus type 2 (HSV2) is one of the most common sexually transmitted infections globally with a very high prevalence in many countries. During HSV2 infection viral particles become coated with complement proteins and antibodies, both existent in the genital fluids, which could influence the activation of the immune responses. In genital mucosa, the primary target cells for HSV2 infection are epithelial cells, but resident immune cells such as dendritic cells (DCs) are also infected. The DCs are the activators of the ensuing immune responses directed against HSV2, and the aim of this study was to examine the effects opsonization of HSV2, either with complement alone or with complement and antibodies, had on the infection of immature DCs and their ability to mount inflammatory and antiviral responses. Complement opsonization of HSV2 enhanced both the direct infection of immature DCs and their production of new infectious viral particles. The enhanced infection required activation of the complement cascade and functional complement receptor 3. Furthermore, HSV2 infection of DCs required endocytosis of viral particles and their delivery into an acid endosomal compartment. The presence of complement in combination with HSV1 or HSV2 specific antibodies more or less abolished the HSV2 infection of DCs.Our results clearly demonstrate the importance of studying HSV2 infection under conditions that ensue in vivo, i.e. when the virions are covered in complement fragments and complement fragments and antibodies, as this will shape the infection and the subsequent immune response and needs to be further elucidated.IMPORTANCE: During HSV2 infection viral particles should become coated with complement proteins and antibodies, both existent in the genital fluids, which could influence the activation of the immune responses. The dendritic cells are the activators of the immune responses directed against HSV2, and the aim of this study was to examine the effects of complement alone or complement and antibodies, on the HSV2 infection of dendritic cells and their ability to mount inflammatory and antiviral responses.Our results demonstrate that the presence of antibodies and complement in the genital environment can influence HSV2 infection under in vitro conditions that reflect the in vivo situation. We believe that our findings are highly relevant for the understanding of HSV2 pathogenesis.
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| 10. |
- Dahlström, Örjan, et al.
(författare)
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The diagnostic accuracies of the 2012 SLICC criteria and the proposed EULAR/ACR criteria for systemic lupus erythematosus classification are comparable
- 2019
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Ingår i: Lupus. - : SAGE PUBLICATIONS LTD. - 0961-2033 .- 1477-0962. ; 28:6, s. 778-782
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Tidskriftsartikel (refereegranskat)abstract
- In a joint effort, the European League Against Rheumatism (EULAR) and the American College of Rheumatology (ACR) recently proposed new criteria for the classification of systemic lupus erythematosus (SLE) with the overarching goal to identify potential participants for clinical studies. Herein, we present the first independent evaluation of these criteria in comparison with older classification grounds using an adult Scandinavian study population of confirmed SLE cases and individuals with SLE-mimicking conditions. We included 56 confirmed SLE cases meeting the 1982 ACR criteria (ACR-82) and/or the Fries diagnostic principle (antinuclear antibodies on at least one occasion plus involvement of at least two defined organ systems) and 55 controls with possible systemic autoimmune disease, including the presence of any SLE-related autoantibody. The proposed EULAR/ACR criteria showed a diagnostic sensitivity of 93% (95% confidence interval (CI), 0.83-0.98) compared with 83% (95% CI, 0.72-0.91) for the updated ACR criteria from 1997. The diagnostic accuracy of all tested classification grounds was fairly similar, achieving approximately 85%. However, the disease specificity of the EULAR/ACR criteria reached only 73% (95% CI, 0.59-0.83), which was comparable with the 2012 Systemic Lupus International Collaborating Clinics (SLICC) criteria, 75% (95% CI, 0.61-0.85), but clearly lower than for ACR-82, 94% (95% CI, 0.83-0.99). In this first independent evaluation of a limited number of cases, we found comparable results with respect to diagnostic sensitivity, specificity and accuracy regarding the SLICC-12 and the proposed EULAR/ACR classification criteria. However, their specificity for SLE appeared to be lower compared with ACR-82.
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