Biomarker Commons

Massive astrocyte destruction in neuromyelitis optica despite natalizumab therapy.

Mult Scler. 2012 Jan;18(1):108-12

Authors: Barnett MH, Prineas JW, Buckland ME, Parratt JD, Pollard JD

Abstract
Auto-antibody mediated astrocyte injury is implicated as a primary event in neuromyelitis optica (NMO) by biomarker, post-mortem and experimental studies that differentiate the condition from multiple sclerosis. We describe the clinical, radiological and neuropathological features of a severe cerebral attack in a natalizumab-treated patient with relapsing myelitis and serum aquaporin-4 antibodies. Our findings support autopsy evidence that abrupt astrocyte destruction precedes demyelination in NMO, and emphasize the importance of serological testing in patients with limited disease. Adherence to current NMO diagnostic criteria may delay treatment, or lead to inappropriate therapy with beta-interferon or natalizumab.

PMID: 21868485 [PubMed - indexed for MEDLINE]

Antigen microarrays identify CNS-produced autoantibodies in RRMS.

Neurology. 2012 Feb 21;78(8):532-9

Authors: Quintana FJ, Farez MF, Izquierdo G, Lucas M, Cohen IR, Weiner HL

Abstract
OBJECTIVE: Multiple sclerosis (MS) is characterized by the local production of antibodies in the CNS and the presence of oligoclonal bands in the CSF. Antigen arrays allow the study of antibody reactivity against a large number of antigens using small volumes of fluid with greater sensitivity than ELISA. We investigated whether there were unique autoantibodies in the CSF of patients with MS as measured by antigen arrays and whether these antibodies differed from those in serum.
METHODS: We used antigen arrays to analyze the reactivity of antibodies in matched serum and CSF samples of 20 patients with untreated relapsing-remitting MS (RRMS), 26 methylprednisolone-treated patients with RRMS, and 20 control patients with other noninflammatory neurologic conditions (ONDs) against 334 different antigens including heat shock proteins, lipids, and myelin antigens.
RESULTS: We found different antibody signatures in matched CSF and serum samples The targets of these antibodies included epitopes of the myelin antigens CNP, MBP, MOBP, MOG, and PLP (59%), HSP60 and HSP70 (38%), and the 68-kD neurofilament (3%). The antibody response in patients with MS was heterogeneous; CSF antibodies in individual patients reacted with different autoantigens. These autoantibodies were locally synthesized in the CNS and were of the immunoglobulin G class. Finally, we found that treatment with steroids decreased autoantibody reactivity, epitope spreading, and intrathecal autoantibody synthesis.
CONCLUSIONS: These studies provide a new avenue to investigate the local antibody response in the CNS, which may serve as a biomarker to monitor both disease progression and response to therapy in MS.

PMID: 22262743 [PubMed - indexed for MEDLINE]

Conformational epitopes of myelin oligodendrocyte glycoprotein are targets of potentially pathogenic antibody responses in multiple sclerosis.

J Neuroinflammation. 2011;8:161

Authors: Menge T, Lalive PH, von Büdingen HC, Genain CP

Abstract
BACKGROUND: Myelin/oligodendrocyte glycoprotein (MOG) is a putative autoantigen in multiple sclerosis (MS). Establishing the pathological relevance and validity of anti-MOG antibodies as biomarkers has yielded conflicting reports mainly due to different MOG isoforms used in different studies. Because epitope specificity may be a key factor determining anti-MOG reactivity we aimed at identifying a priori immunodominant MOG epitopes by monoclonal antibodies (mAbs) and at assessing clinical relevance of these epitopes in MS.
METHODS: Sera of 325 MS patients, 69 patients with clinically isolated syndrome and 164 healthy controls were assayed by quantitative, high-throughput ELISA for reactivity to 3 different MOG isoforms, and quantitative titers correlated with clinical characteristics. mAbs defined unique immunodominant epitopes distinct to each of the isoforms.
RESULTS: In the majority of human samples anti-MOG levels were skewed towards low titers. However, in 8.2% of samples high-titer anti-MOG antibodies were identified. In contrast to anti-MOG reactivity observed in a mouse model of MS, in patients with MS these never reacted with ubiquitously exposed epitopes. Moreover, in patients with relapsing-remitting MS high-titer anti-MOG IgG correlated with disability (EDSS; Spearman r = 0.574; p = 0.025).
CONCLUSIONS: Thus high-titer reactivity likely represents high-affinity antibodies against pathologically relevant MOG epitopes, that are only present in a small proportion of patients with MS. Our study provides valuable information about requirements of anti-MOG reactivity for being regarded as a prognostic biomarker in a subtype of MS.

PMID: 22093619 [PubMed - indexed for MEDLINE]

Development of biomarkers for multiple sclerosis as a neurodegenerative disorder.

Prog Neurobiol. 2011 Dec;95(4):670-85

Authors: Ziemann U, Wahl M, Hattingen E, Tumani H

Abstract
Multiple sclerosis (MS) is the most common neurological disorder leading to permanent disability in young adults in the developed world. While traditionally conceived as an autoimmune inflammatory disease it is becoming increasingly evident that axonal and neuronal degeneration occur, at least partly independent of inflammation, and already at the earliest stages of the disease. In addition, it is the progressive neurodegeneration which determines the amount of accumulating clinical disability. Therefore, MS should be considered as a neurodegenerative disorder. Development of disease-modifying drugs to treat MS is currently highly dynamic. Already, several drugs have shown short-term efficacy to delay progression of clinical disability, but the ultimate aim is to halt disease progression. In this context, the development of sensitive, reliable and valid biomarkers to measure neurodegeneration is an indispensible need to facilitate successful informative clinical trials. While no such biomarker is currently fully established, several promising candidate biomarkers obtained with multimodal techniques, including cerebrospinal fluid and serum analysis, neuroimaging and neurophysiology, are presently developed and evaluated. This paper compiles an up-to-date critical review of the available knowledge of candidate biomarkers of neurodegenerative processes in MS.

PMID: 21524682 [PubMed - indexed for MEDLINE]

The MethDet: a technology for biomarker development.

Expert Rev Mol Diagn. 2011 Nov;11(8):807-12

Authors: Levenson VV, Melnikov AA

Abstract
Early detection and diagnosis of a disease in its presymptomatic form has to rely on biomarkers, and multiple laboratories are involved in their development and validation. In this article, we describe our work on a platform technology for a genome-wide analysis of DNA methylation while still using a small amount of sample - a biopsy, a section from a formalin-fixed paraffin-embedded tissue or a small volume (0.4 ml) of plasma from blood. This technology (methylation detection or MethDet) allows genome-wide association studies similar to the analysis of single-nucleotide polymorphisms. Instead of mostly static genetic differences, the MethDet technology tests disease-dependent changes of epigenetic makeup, which is closely related to the gene expression pattern of a disease. The MethDet assay has the capacity to utilize highly fragmented DNA (e.g., cell-free circulating DNA from plasma) to identify disease-specific changes, effects of treatment or changes in the disease activity.

PMID: 22022943 [PubMed - indexed for MEDLINE]

Biomarkers of disease activity in multiple sclerosis.

J Neurol Sci. 2011 Jun 15;305(1-2):1-10

Authors: Graber JJ, Dhib-Jalbut S

Abstract
As therapeutic options for multiple sclerosis widen, validated biomarkers of clinical disease activity are urgently needed. Reliable biomarkers would assist in choosing initial therapy, monitoring response to therapy, detecting subclinical disease activity, predicting and possibly preventing therapeutic failure, and hopefully improving both short (relapses) and long-term (disability) outcomes. The presence of oligoclonal bands in the cerebrospinal fluid is a well-validated biomarker that is useful in initial diagnosis. Neutralizing antibodies to interferon-beta are also useful in identifying treatment failure and possibly guiding changes in therapy. The discovery of antibodies to aquaporin-4 in patients with neuromyelitis optica delineates patients with a fundamentally different underlying pathophysiology and clinical course who may require alternate therapeutic approaches. While numerous other candidate biomarkers in serum and cerebrospinal fluid have been described, none so far have the validated reliability necessary for widespread clinical use. The availability of multiple genetic and protein microarray technology may assist in identifying more reliable candidate biomarkers or patterns of multiple biomarkers and improve specificity. The heterogeneity of multiple sclerosis may necessitate individualized biomarkers and therapeutic decisions within distinct subsets of patients.

PMID: 21463872 [PubMed - indexed for MEDLINE]

Investigation of autoantibody profiles for cerebrospinal fluid biomarker discovery in patients with relapsing-remitting multiple sclerosis.

J Neuroimmunol. 2012 Jan 18;242(1-2):26-32

Authors: Beyer NH, Lueking A, Kowald A, Frederiksen JL, Heegaard NH

Abstract
Using the UNIarray® marker technology platform, cerebrospinal fluid immunoglobulin G reactivities of 15 controls and 17 RRMS patients against human recombinant proteins were investigated. Patient cerebrospinal fluids were oligoclonal band positive and reactivities were compared to that of sex- and age-matched controls. We hereby aimed at the characterization of autoreactivity in patients with RRMS. Differences in autoreactivities between control and RRMS samples were identified comprising autoantigens identified in this study only and previously reported autoantigens as well. A combination of the 10-15 most significant proteins may be investigated further as autoantigens for diagnostic purposes. Additional investigations may include minimizing the number of proteins used in such diagnostic tests.

PMID: 22177943 [PubMed - indexed for MEDLINE]

Molecular outcomes of neuromyelitis optica (NMO)-IgG binding to aquaporin-4 in astrocytes.

Proc Natl Acad Sci U S A. 2012 Jan 24;109(4):1245-50

Authors: Hinson SR, Romero MF, Popescu BF, Lucchinetti CF, Fryer JP, Wolburg H, Fallier-Becker P, Noell S, Lennon VA

Abstract
The astrocytic aquaporin-4 (AQP4) water channel is the target of pathogenic antibodies in a spectrum of relapsing autoimmune inflammatory central nervous system disorders of varying severity that is unified by detection of the serum biomarker neuromyelitis optica (NMO)-IgG. Neuromyelitis optica is the most severe of these disorders. The two major AQP4 isoforms, M1 and M23, have identical extracellular residues. This report identifies two novel properties of NMO-IgG as determinants of pathogenicity. First, the binding of NMO-IgG to the ectodomain of astrocytic AQP4 has isoform-specific outcomes. M1 is completely internalized, but M23 resists internalization and is aggregated into larger-order orthogonal arrays of particles that activate complement more effectively than M1 when bound by NMO-IgG. Second, NMO-IgG binding to either isoform impairs water flux directly, independently of antigen down-regulation. We identified, in nondestructive central nervous system lesions of two NMO patients, two previously unappreciated histopathological correlates supporting the clinical relevance of our in vitro findings: (i) reactive astrocytes with persistent foci of surface AQP4 and (ii) vacuolation in adjacent myelin consistent with edema. The multiple molecular outcomes identified as a consequence of NMO-IgG interaction with AQP4 plausibly account for the diverse pathological features of NMO: edema, inflammation, demyelination, and necrosis. Differences in the nature and anatomical distribution of NMO lesions, and in the clinical and imaging manifestations of disease documented in pediatric and adult patients, may be influenced by regional and maturational differences in the ratio of M1 to M23 proteins in astrocytic membranes.

PMID: 22128336 [PubMed - indexed for MEDLINE]

More than just a T-box: the role of T-bet as a possible biomarker and therapeutic target in autoimmune diseases.

Immunotherapy. 2011 Mar;3(3):435-41

Authors: Ji N, Sosa RA, Forsthuber TG

Abstract
T-bet was initially described as a T-box transcription factor with an essential role in orchestrating Th1 cell differentiation. Subsequently, it was determined that T-bet controls the expression of numerous cytokines and their receptors, adhesion molecules and chemokine receptors, and therefore determines the differentiation and development status of many types of immune cells. The critical role of T-bet in autoimmune diseases, particularly multiple sclerosis and its animal model experimental autoimmune encephalomyelitis, implicates it as a potential biomarker for pathogenic T cells as well as a therapeutic drug target.

PMID: 21395384 [PubMed - indexed for MEDLINE]

Neuromyelitis optica (NMO)--an autoimmune disease of the central nervous system (CNS).

Acta Neurol Scand. 2011 Jun;123(6):369-84

Authors: Asgari N, Owens T, Frøkiaer J, Stenager E, Lillevang ST, Kyvik KO

Abstract
In the past 10 years, neuromyelitis optica (NMO) has evolved from Devic's categorical clinical description into a broader disease spectrum. Serum IgG antibodies have been identified in NMO patients with the water channel aquaporin-4 (AQP4) as their main target antigen. AQP4 antibodies/NMO-IgG have been shown to be a highly specific and moderately sensitive serum biomarker for NMO. The immunopathology of NMO lesions supports that anti-AQP4 antibodies/NMO-IgG are involved in the pathogenesis of NMO. In vitro studies have demonstrated that human NMO-IgG induce necrosis and impair glutamate transport in astrocytes. Certain ethnic groups, notably of Asian and African origin, seem to be more susceptible to NMO than others. The genetic background for these putative differences is not known, a weak human leucocyte antigen association has been identified. AQP4 gene variants could represent a genetic susceptibility factor for different clinical phenotypes within the NMO spectrum. Experimental models have been described including a double-transgenic myelin-specific B- and T-cell mouse. NMO-like disease has been induced with passive transfer of human anti-AQP4 antibodies to the plasma of mice with pre-established experimental autoimmune encephalomyelitis or by intrathecal administration to naive mice. NMO may be characterized as a channelopathy of the central nervous system with autoimmune characteristics.

PMID: 20880299 [PubMed - indexed for MEDLINE]

Neuromyelitis optica immunoglobulin G in Chinese patients detected by immunofluorescence assay on a monkey brain substrate.

Neuroimmunomodulation. 2012;19(1):20-4

Authors: Long Y, Hu X, Peng F, Lu Z, Wang Y, Yang Y, Qiu W

Abstract
BACKGROUND: Serum neuromyelitis optica immunoglobulin G (NMO-IgG) is used as a biomarker to differentiate between neuromyelitis optica (NMO) and multiple sclerosis (MS). However, the original assay is expensive and complex and shows low sensitivity. Here, we investigated the potential of NMO-IgG detection using an indirect immunofluorescence (IIF) assay on monkey brains.
METHODS: NMO-IgG seroprevalence was determined in 168 samples by an IIF assay on a monkey brain substrate. The data were compared with those from a standard mouse brain IIF assay using McNemar and kappa tests.
RESULTS: Thirty-one of 50 (62%) NMO patients, 7 of 18 (38.9%) longitudinally extensive transverse myelitis patients, 6 of 57 (10.5%) MS patients, and 5 of 10 (50%) optic neuritis patients were seropositive for NMO-IgG. None of the acute partial transverse myelitis patients (n = 3) or healthy controls (n = 20) was positive. Thus, the sensitivity of the test was 62% for the patients with clinically definite NMO. The specificity was 89.5%, considering the 57 MS patients as the control group. The modified IIF assay on monkey brains and the standard IIF assay based on mouse brains were not significantly different (McNemar test; p = 1.000). The two assays were concordant in 39 seropositive samples and 100 seronegative samples (kappa test; kappa = 0.592, p < 0.0001).
CONCLUSIONS: Although the modified IIF monkey brain assay was no better than the standard mouse brain IIF assay, we affirmed that NMO-IgG is a sensitive and specific biomarker to differentiate between NMO and MS.

PMID: 22067618 [PubMed - indexed for MEDLINE]

Incorporation of an interferon-β neutralizing antibody assay into routine clinical practice.

Mult Scler. 2011 Nov;17(11):1333-40

Authors: Farrell RA, Espasandin M, Lakdawala N, Creeke PI, Worthington V, Giovannoni G

Abstract
BACKGROUND: Incorporation of routine clinical testing for neutralizing antibodies (NAbs) to interferon (IFN)-β has remained problematic. With increasing treatment choice for patients, routine NAb testing should be incorporated to aid therapeutic decisions.
OBJECTIVE: We sought to improve interpretation of NAb results by combining the luciferase NAb assay (luciferase gene expression assay under control of interferon-stimulated response element) and in-vivo biomarker (myxovirus A protein, MxA) induction in patients with MS.
METHODS: Blood samples (serum and PAXGene(®) for RNA) were obtained pre-injection and 12 hours post-injection of IFN-β from 144 subjects. Sera were tested for NAbs using the luciferase assay. MxA expression was quantified by real-time polymerase chain reaction (PCR).
RESULTS: 26% of samples were NAb positive (titre > 20 NU). There was no difference in NAb titres in the pre- or post-dose sera (p = 0.643). MxA expression was inhibited in a dose-dependent fashion in NAb positive samples. Mean MxA level post-IFN-β: NAb negative 2330 (95% CI 1940-2719), NAb 20-99 NU 1533 (95% CI 741-2324), NAb 100-600 NU 832 (186-1478) and NAb > 600 NU 101 (95% CI 0-224). NAb titre and MxA level correlated strongly: MxA pre- (Spearman r = -0.72, p < 0.0001), MxA post- (Spearman r = -0.79, p < 0.0001) and MxA induction (Spearman r = -0.67, p = 0.0004).
CONCLUSION: A single, 12-hour post-injection sample should be used to test for NAbs using the luciferase assay and IFN-β bioactivity (MxA) in the clinical setting.

PMID: 21685230 [PubMed - indexed for MEDLINE]

Interferon regulatory factor 5 gene variants and pharmacological and clinical outcome of Interferonβ therapy in multiple sclerosis.

Genes Immun. 2011 Sep;12(6):466-72

Authors: Vosslamber S, van der Voort LF, van den Elskamp IJ, Heijmans R, Aubin C, Uitdehaag BM, Crusius JB, van der PouwKraan TC, Comabella M, Montalban X, Hafler DA, De Jager PL, Killestein J, Polman CH, Verweij CL

Abstract
Interferon-β (IFNβ) therapy is effective in approximately half of the patients with relapsing-remitting multiple sclerosis (RRMS). Clinical non-responders were characterized by an increased expression of IFN response genes before the start of therapy, and a lack of a pharmacologically induced increase in IFN response gene activity. Because Interferon Regulatory Factor 5 (IRF5) is a master regulator of IFN-activity, we carried out a candidate gene study of IRF5 gene variants in relation to the pharmacological and clinical response upon IFNβ treatment. We found that patients with the IRF5 rs2004640-TT and rs47281420-AA genotype exerted a poor pharmacological response to IFNβ compared with patients carrying the respective G-alleles (P=0.0006 and P=0.0023, respectively). Moreover, patients with the rs2004640-TT genotype developed more magnetic resonance imaging (MRI)-based T2 lesions during IFNβ treatment (P=0.003). Accordingly, an association between MRI-based non-responder status and rs2004640-TT genotype was observed (P=0.010). For the rs4728142-AA genotype a trend of an association with more T2 lesions during IFNβ treatment and MRI-based non-responder status was observed (P=0.103 and P=0.154, respectively). The clinical relevance of the rs2004640-TT genotype was validated in an independent cohort wherein a shorter time to first relapse was found (P=0.037). These findings suggest a role for IRF5 gene variation in the pharmacological and clinical outcome of IFNβ therapy that might have relevance as biomarker to predict the response to IFNβ in multiple sclerosis.

PMID: 21471993 [PubMed - indexed for MEDLINE]