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- Knevel, R., et al.
(author)
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A genetic variant in granzyme B is associated with progression of joint destruction in rheumatoid arthritis
- 2013
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In: Arthritis and Rheumatism. - : Wiley. - 1529-0131 .- 0004-3591. ; 65:3, s. 582-589
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Journal article (peer-reviewed)abstract
- Objective Genetic factors account for an estimated 4558% of the variance in joint destruction in rheumatoid arthritis (RA). The serine proteinase granzyme B induces target cell apoptosis, and several in vitro studies suggest that granzyme B is involved in apoptosis of chondrocytes. Serum levels of granzyme B are increased in RA and are also associated with radiographic erosions. The aim of this study was to investigate GZMB as a candidate gene accounting for the severity of joint destruction in RA. Methods A total of 1,418 patients with 4,885 radiograph sets of the hands and feet from 4 independent cohorts were studied. First, explorative analyses were performed in 600 RA patients in the Leiden Early Arthritis Clinic cohort. Fifteen single-nucleotide polymorphisms (SNPs) tagging GZMB were tested. Significantly associated SNPs were genotyped in data sets representing patients from the Groningen, Sheffield, and Lund cohorts. In each data set, the relative increase in the annual rate of progression in the presence of a genotype was assessed. Data were summarized in a meta-analysis. The association of GZMB with the RNA expression level of the GZMB genomic region was tested by mapping expression quantitative trait loci (QTLs) on 1,469 whole blood samples. Results SNP rs8192916 was significantly associated with the rate of joint destruction in the first cohort and in the meta-analysis of all data sets. Patients homozygous for the minor allele of rs8192916 had a higher rate of joint destruction per year compared with other patients (P = 7.8 x 104). Expression QTL of GZMB identified higher expression in the presence of the minor allele of rs8192916 (P = 2.27 x 105). Conclusion SNP rs8192916 located in GZMB is associated with the progression of joint destruction in RA as well as with RNA expression in whole blood.
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- Knevel, R., et al.
(author)
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Genetic variants in IL15 associate with progression of joint destruction in rheumatoid arthritis: a multicohort study
- 2012
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In: Annals of the Rheumatic Diseases. - : BMJ. - 1468-2060 .- 0003-4967. ; 71:10, s. 1651-1657
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Journal article (peer-reviewed)abstract
- Background Interleukin (IL)-15 levels are increased in serum, synovium and bone marrow of patients with rheumatoid arthritis (RA). IL-15 influences both the innate and the adaptive immune response; its major role is activation and proliferation of T cells. There are also emerging data that IL-15 affects osteoclastogenesis. The authors investigated the association of genetic variants in IL15 with the rate of joint destruction in RA. Method 1418 patients with 4885 x-ray sets of both hands and feet of four independent data sets were studied. First, explorative analyses were performed on 600 patients with early RA enrolled in the Leiden Early Arthritis Clinic. Twenty-five single-nucleotide polymorphisms (SNPs) tagging IL-15 were tested. Second, SNPs with significant associations in the explorative phase were genotyped in data sets from Groningen, Sheffield and Lund. In each data set, the relative increase of the progression rate per year in the presence of a genotype was assessed. Subsequently, data were summarised in an inverse weighting meta-analysis. Results Five SNPs were significantly associated with rate of joint destruction in phase 1 and typed in the other data sets. Patients homozygous for rs7667746, rs7665842, rs2322182, rs6821171 and rs4371699 had respectively 0.94-, 1.04-, 1.09-, 1.09- and 1.09- fold rate of joint destruction compared to other patients (p = 4.0x10(-6), p = 3.8x10(-4), p = 5.0x10(-3), p = 5.0x10(-3) and p = 9.4x10(-3)). Discussion Independent replication was not obtained, possibly due to insufficient power. Meta-analyses of all data sets combined resulted in significant results for four SNPs (rs7667746, p < 0.001; rs7665842, p < 0.001; rs4371699, p = 0.01; rs6821171, p = 0.01). These SNPs were also significant after correction for multiple testing. Conclusion Genetic variants in IL-15 are associated with progression of joint destruction in RA.
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- Le Bas-Bernardet, S, et al.
(author)
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Bortezomib, C1-Inhibitor and Plasma Exchange Do Not Prolong the Survival of Multi-Transgenic GalT-KO Pig Kidney Xenografts in Baboons.
- 2015
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In: American journal of transplantation : official journal of the American Society of Transplantation and the American Society of Transplant Surgeons. - : Elsevier BV. - 1600-6143. ; 15:2, s. 358-70
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Journal article (peer-reviewed)abstract
- Galactosyl-transferase KO (GalT-KO) pigs represent a potential solution to xenograft rejection, particularly in the context of additional genetic modifications. We have performed life supporting kidney xenotransplantation into baboons utilizing GalT-KO pigs transgenic for human CD55/CD59/CD39/HT. Baboons received tacrolimus, mycophenolate mofetil, corticosteroids and recombinant human C1 inhibitor combined with cyclophosphamide or bortezomib with or without 2-3 plasma exchanges. One baboon received a control GalT-KO xenograft with the latter immunosuppression. All immunosuppressed baboons rejected the xenografts between days 9 and 15 with signs of acute humoral rejection, in contrast to untreated controls (n=2) that lost their grafts on days 3 and 4. Immunofluorescence analyses showed deposition of IgM, C3, C5b-9 in rejected grafts, without C4d staining, indicating classical complement pathway blockade but alternate pathway activation. Moreover, rejected organs exhibited predominantly monocyte/macrophage infiltration with minimal lymphocyte representation. None of the recipients showed any signs of porcine endogenous retrovirus transmission but some showed evidence of porcine cytomegalovirus (PCMV) replication within the xenografts. Our work indicates that the addition of bortezomib and plasma exchange to the immunosuppressive regimen did not significantly prolong the survival of multi-transgenic GalT-KO renal xenografts. Non-Gal antibodies, the alternative complement pathway, innate mechanisms with monocyte activation and PCMV replication may have contributed to rejection.
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- Smailhodzic, Dzenita, et al.
(author)
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Zinc supplementation inhibits complement activation in age-related macular degeneration.
- 2014
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In: PLoS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 9:11
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Journal article (peer-reviewed)abstract
- Age-related macular degeneration (AMD) is the leading cause of blindness in the Western world. AMD is a multifactorial disorder but complement-mediated inflammation at the level of the retina plays a pivotal role. Oral zinc supplementation can reduce the progression of AMD but the precise mechanism of this protective effect is as yet unclear. We investigated whether zinc supplementation directly affects the degree of complement activation in AMD and whether there is a relation between serum complement catabolism during zinc administration and the complement factor H (CFH) gene or the Age-Related Maculopathy susceptibility 2 (ARMS2) genotype. In this open-label clinical study, 72 randomly selected AMD patients in various stages of AMD received a daily supplement of 50 mg zinc sulphate and 1 mg cupric sulphate for three months. Serum complement catabolism-defined as the C3d/C3 ratio-was measured at baseline, throughout the three months of supplementation and after discontinuation of zinc administration. Additionally, downstream inhibition of complement catabolism was evaluated by measurement of anaphylatoxin C5a. Furthermore, we investigated the effect of zinc on complement activation in vitro. AMD patients with high levels of complement catabolism at baseline exhibited a steeper decline in serum complement activation (p<0.001) during the three month zinc supplementation period compared to patients with low complement levels. There was no significant association of change in complement catabolism and CFH and ARMS2 genotype. In vitro zinc sulphate directly inhibits complement catabolism in hemolytic assays and membrane attack complex (MAC) deposition on RPE cells. This study provides evidence that daily administration of 50 mg zinc sulphate can inhibit complement catabolism in AMD patients with increased complement activation. This could explain part of the mechanism by which zinc slows AMD progression.
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| 6. |
- Van de Wouwer, M., et al.
(author)
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The lectin-like domain of thrombomodulin interferes with complement activation and protects against arthritis
- 2006
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In: Journal of Thrombosis and Haemostasis. - : Elsevier BV. - 1538-7933 .- 1538-7836. ; 4:8, s. 1813-1824
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Journal article (peer-reviewed)abstract
- Background: Thrombomodulin (TM) is predominantly a vascular endothelial cell plasma membrane glycoprotein that, via distinct structural domains, interacts with multiple ligands, thereby modulating coagulation, fibrinolysis, complement activation, inflammation and cell proliferation. We previously reported that by mediating signals that interfere with mitogen-activated protein kinase and nuclear factor kappa B pathways, the amino-terminal C-type lectin-like domain of TM has direct anti-inflammatory properties. Methods: In the current study, we use murine models of acute inflammatory arthritis and biochemical approaches to assess the mechanism by which the lectin-like domain of TM modifies disease progression. Results: Mice lacking the lectin-like domain of TM (TM(LeD/LeD)mice) develop inflammatory arthritis that is more rapid in onset and more severe than that developed in their wildtype counterparts. In two models of arthritis, treatment of mice with recombinant soluble lectin-like domain of TM significantly suppresses clinical evidence of disease and diminishes monocyte/macrophage infiltration into the synovium, with weaker expression of the pro-inflammatory high mobility group box chromosomal protein 1. While thrombin-TM mediated activation of thrombin activatable fibrinolysis inhibitor inactivates complement factors C3a and C5a, we show that TM has a second independent mechanism to regulate complement: the lectin-like domain of TM directly interferes with complement activation via the classical and lectin pathways. Conclusions: These data extend previous insights into the mechanisms by which TM modulates innate immunity, and highlight its potential as a therapeutic target for inflammatory diseases.
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| 10. |
- Seelen, MA, et al.
(author)
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Functional analysis of the classical, alternative, and MBL pathways of the complement system: standardization and validation of a simple ELISA
- 2005
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In: Journal of Immunological Methods. - : Elsevier BV. - 1872-7905 .- 0022-1759. ; 296:1-2, s. 187-198
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Journal article (peer-reviewed)abstract
- Primary defence against invading microorganisms depends on a functional innate immune system and the complement system plays a major role in such immunity. Deficiencies in one of the components of the complement system can cause severe and recurrent infections, systemic diseases, such as systemic lupus erythematosus (SLE) and renal disease. Screening for complement deficiencies in the classical or alternative complement pathways has mainly been performed by haemolytic assays. Here. we describe a simple ELISA-based format for the evaluation of three pathways of complement activation. The assays are based on specific coatings for each pathway in combination with specific buffer systems. We have standardized these assays and defined cut off values to detect complement deficiencies at the different levels of the complement system. The results demonstrate the value of these ELISA-based procedures for the functional assessment of complement deficiencies in clinical practice. The assay is now available commercially in kit form.
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