| 1. |
- Beecham, Ashley H, et al.
(författare)
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Analysis of immune-related loci identifies 48 new susceptibility variants for multiple sclerosis.
- 2013
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Ingår i: Nature genetics. - : Springer Science and Business Media LLC. - 1546-1718 .- 1061-4036. ; 45:11, s. 1353-60
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Tidskriftsartikel (refereegranskat)abstract
- Using the ImmunoChip custom genotyping array, we analyzed 14,498 subjects with multiple sclerosis and 24,091 healthy controls for 161,311 autosomal variants and identified 135 potentially associated regions (P < 1.0 × 10(-4)). In a replication phase, we combined these data with previous genome-wide association study (GWAS) data from an independent 14,802 subjects with multiple sclerosis and 26,703 healthy controls. In these 80,094 individuals of European ancestry, we identified 48 new susceptibility variants (P < 5.0 × 10(-8)), 3 of which we found after conditioning on previously identified variants. Thus, there are now 110 established multiple sclerosis risk variants at 103 discrete loci outside of the major histocompatibility complex. With high-resolution Bayesian fine mapping, we identified five regions where one variant accounted for more than 50% of the posterior probability of association. This study enhances the catalog of multiple sclerosis risk variants and illustrates the value of fine mapping in the resolution of GWAS signals.
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| 2. |
- Petzold, Axel, et al.
(författare)
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Neurofilament ELISA validation
- 2010
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Ingår i: JOURNAL OF IMMUNOLOGICAL METHODS. - 0022-1759. ; 352:1-2, s. 23-31
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Tidskriftsartikel (refereegranskat)
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| 3. |
- Petzold, Axel, et al.
(författare)
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Neurofilament ELISA validation
- 2010
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Ingår i: JIM - Journal of Immunological Methods. - : Elsevier BV. - 0022-1759 .- 1872-7905. ; 352:1-2, s. 23-31
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Neurofilament proteins (Nf) are highly specific biomarkers for neuronal death and axonal degeneration. As these markers become more widely used, an inter-laboratory validation study is required to identify assay criteria for high quality performance. METHODS: The UmanDiagnostics NF-light (R)enzyme-linked immunoabsorbent assays (ELISA) for the neurofilament light chain (NfL, 68kDa) was used to test the intra-assay and inter-laboratory coefficient of variation (CV) between 35 laboratories worldwide on 15 cerebrospinal fluid (CSF) samples. Critical factors, such as sample transport and storage, analytical delays, reaction temperature and time, the laboratories' accuracy and preparation of standards were documented and used for the statistical analyses. RESULTS: The intra-laboratory CV averaged 3.3% and the inter-laboratory CV 59%. The results from the test laboratories correlated with those from the reference laboratory (R=0.60, p<0.0001). Correcting for critical factors improved the strength of the correlation. Differences in the accuracy of standard preparation were identified as the most critical factor. Correcting for the error introduced by variation in the protein standards improved the correlation to R=0.98, p<0.0001 with an averaged inter-laboratory CV of 14%. The corrected overall inter-rater agreement was subtantial (0.6) according to Fleiss' multi-rater kappa and Gwet's AC1 statistics. CONCLUSION: This multi-center validation study identified the lack of preparation of accurate and consistent protein standards as the main reason for a poor inter-laboratory CV. This issue is also relevant to other protein biomarkers based on this type of assay and will need to be solved in order to achieve an acceptable level of analytical accuracy. The raw data of this study is available online.
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| 4. |
- Rosenling, Therese, et al.
(författare)
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Profiling and Identification of Cerebrospinal Fluid Proteins in a Rat EAE Model of Multiple Sclerosis.
- 2012
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Ingår i: Journal of Proteome Research. - 1535-3893 .- 1535-3907. ; 11:4, s. 2048-2060
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Tidskriftsartikel (refereegranskat)abstract
- The experimental autoimmune encephalomyelitis (EAE) model resembles certain aspects of multiple sclerosis (MScl), with common features such as motor dysfunction, axonal degradation, and infiltration of T-cells. We studied the cerebrospinal fluid (CSF) proteome in the EAE rat model to identify proteomic changes relevant for MScl disease pathology. EAE was induced in male Lewis rats by injection of myelin basic protein (MBP) together with complete Freund's adjuvant (CFA). An inflammatory control group was injected with CFA alone, and a nontreated group served as healthy control. CSF was collected at day 10 and 14 after immunization and analyzed by bottom-up proteomics on Orbitrap LC-MS and QTOF LC-MS platforms in two independent laboratories. By combining results, 44 proteins were discovered to be significantly increased in EAE animals compared to both control groups, 25 of which have not been mentioned in relation to the EAE model before. Lysozyme C1, fetuin B, T-kininogen, serum paraoxonase/arylesterase 1, glutathione peroxidase 3, complement C3, and afamin are among the proteins significantly elevated in this rat EAE model. Two proteins, afamin and complement C3, were validated in an independent sample set using quantitative selected reaction monitoring mass spectrometry. The molecular weights of the identified differentially abundant proteins indicated an increased transport across the blood-brain barrier (BBB) at the peak of the disease, caused by an increase in BBB permeability.
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| 5. |
- Stoop, Marcel, et al.
(författare)
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Minocycline effects on the CSF proteome of Experimental Autoimmune Encephalomyelitis rats.
- 2012
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Ingår i: Journal of Proteome Research. - 1535-3893 .- 1535-3907.
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Tidskriftsartikel (refereegranskat)abstract
- To identify response biomarkers for pharmaceutical treatment of Multiple Sclerosis, we induced Experimental Autoimmune Encephalomyelitis (EAE) in rats and treated symptomatic animals with minocycline. Cerebrospinal fluid (CSF) samples were collected fourteen days after EAE induction at the peak of neurological symptoms and proteomics analysis was performed using nano-LC-Orbitrap mass spectrometry. Additionally, the minocycline concentration in CSF was determined using quantitative MALDI-triple-quadrupole tandem mass spectrometry (MALDI-MS/MS) in the selected reaction monitoring (SRM) mode. Fifty percent of the minocycline-treated EAE animals did not show neurological symptoms on day 14 ("responders"), whilst the other half displayed neurological symptoms ("non-responders"), indicating that minocycline delayed disease onset and attenuated disease severity in some, but not all, animals. Neither CSF nor plasma minocycline concentrations correlated with the onset of symptoms or disease severity. Analysis of the proteomics data resulted in a list of 20 differentially abundant proteins between the untreated animals and the responder group of animals. Two of these proteins, complement C3 and carboxypeptidase B2, were validated by quantitative LC-MS/MS in the SRM mode. Differences in the CSF proteome between untreated EAE animals and minocycline-treated responders were similar to the differences between minocycline-treated responders and non-responders (70% overlap). Six proteins that remained unchanged in the minocycline-treated animals but were elevated in untreated EAE animals may be related to the mechanism of action of minocycline.
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| 6. |
- Stoop, Marcel P, et al.
(författare)
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Quantitative proteomics and metabolomics analysis of normal human cerebrospinal fluid samples.
- 2010
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Ingår i: Molecular & Cellular Proteomics. - 1535-9476 .- 1535-9484. ; 9:9, s. 2063-75
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Tidskriftsartikel (refereegranskat)abstract
- The analysis of cerebrospinal fluid (CSF) is used in biomarker discovery studies for various neurodegenerative central nervous system (CNS) disorders. However, little is known about variation of CSF proteins and metabolites between patients without neurological disorders. A baseline for a large number of CSF compounds appears to be lacking. To analyze the variation in CSF protein and metabolite abundances in a number of well-defined individual samples of patients undergoing routine, non-neurological surgical procedures, we determined the variation of various proteins and metabolites by multiple analytical platforms. A total of 126 common proteins were assessed for biological variations between individuals by ESI-Orbitrap. A large spread in inter-individual variation was observed (relative standard deviations [RSDs] ranged from 18 to 148%) for proteins with both high abundance and low abundance. Technical variation was between 15 and 30% for all 126 proteins. Metabolomics analysis was performed by means of GC-MS and nuclear magnetic resonance (NMR) imaging and amino acids were specifically analyzed by LC-MS/MS, resulting in the detection of more than 100 metabolites. The variation in the metabolome appears to be much more limited compared with the proteome: the observed RSDs ranged from 12 to 70%. Technical variation was less than 20% for almost all metabolites. Consequently, an understanding of the biological variation of proteins and metabolites in CSF of neurologically normal individuals appears to be essential for reliable interpretation of biomarker discovery studies for CNS disorders because such results may be influenced by natural inter-individual variations. Therefore, proteins and metabolites with high variation between individuals ought to be assessed with caution as candidate biomarkers because at least part of the difference observed between the diseased individuals and the controls will not be caused by the disease, but rather by the natural biological variation between individuals.
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