Similar low frequency of anti-MOG IgG and IgM in MS patients and healthy subjects

Role of pathogenic T cells and autoantibodies in relapse and progression of myelin oligodendrocyte glycoprotein-induced autoimmune encephalomyelitis in LEW.1AV1 rats

Accumulating evidence suggests that T cells and autoantibodies reactive with myelin oligodendrocyte glycoprotein (MOG) play a critical role in the pathogenesis of multiple sclerosis (MS). In the present study, we have tried to elucidate the pathomechanisms of development and progression of the disease by analysing T cells and autoantibodies in MOG-induced rat experimental autoimmune encephalomyelitis (EAE), which exhibits various clinical subtypes mimicking MS. Analysis using overlapping peptides revealed that encephalitogenic epitopes resided in peptide 7 (P7, residue 91-108) and P8 (residue 103-125) of MOG. Immunization with MOGP7 and MOGP8 induced relapsing-remitting or secondary progressive EAE. T cells taken from MOG-immunized and MOGP7-immunized rats responded to MOG and MOGP7 and sera from MOG-immunized rats reacted to MOG and MOGP1. Significant epitope spreading was not observed at either T-cell or antibody levels. Interestingly, sera from MOGP7-immunized rats with clinical signs did not react to MOG and MOG peptides throughout the observation period, suggesting that disease development and relapse in MOGP7-induced EAE occur without autoantibodies. However, MOGP7 immunization with adoptive transfer of anti-MOG antibodies aggravated the clinical course of EAE only slightly. Analysis of antibodies against conformational epitope (cme) suggests that anti-MOG(cme) may play a role in the pathogenicity of anti-MOG antibodies. Collectively, these findings demonstrated that relapse of a certain type of MOG-induced EAE occurs without autoantibodies but that autoantibodies may play a role in disease progression. Relapses and the progression of MS-mimicking EAE are differently immunoregulated so immunotherapy should be designed appropriately on the basis of precise information.

B-cells and humoral immunity in multiple sclerosis. Implications for therapy

B-cells and humoral immunity have been implicated in the pathogenesis of multiple sclerosis. The most common pattern of demyelinating pathology in multiple sclerosis is associated with the deposition of antibodies and the activation of complement, as well as T-cells and macrophages. Plasmapheresis has been found to be an efficient therapeutic approach in patients with this type of pathological lesion. Recent data have indicated that autoantibodies and complement C5b-9 may be involved in lesion formation and might also be beneficial for lesion repair. Thus, the role played by B-cells and humoral immunity is rather complex, and new strategies for targeting B-cell responses are continuing to emerge.

The role of the humoral immune system in multiple sclerosis (MS) and its animal model experimental autoimmune encephalomyelitis (EAE)

The pathogenic events in multiple sclerosis (MS) that result in immune cell infiltration, multifocal demyelination and axonal loss have been focused by the strong impact of the classical MS model experimental autoimmune encephalomyelitis (EAE) towards the hypothesis that MS is an entirely T cell-mediated disease. Although conspicuous humoral immune responses have been known since Kabal's seminal finding of elevated immunoglobulins (Igs) in the cerebrospinal fluid (CSF), only in the past few years evidence derived from recent studies of the MS lesion of anti-myelin antibodies (Abs) in patients with early MS and of MS animal models has led to a renewed interest in the role for B cells, plasma cells and their products in the pathogenesis of MS. This review surveys the actual data concerning the role of the humoral immune system in MS and EAE and explains potential modes of action and long-time persistence in the inflamed brain tissue as a B cell-supportive microenvironment in MS. These mechanisms include the modulation of antigen presentation and costimulation to T cells, increased myelin opsonisation und recruitment of inflammatory cells to the CNS, but also immunoregulatory influences on the remyelination by anti-myelin B cells and Abs. So, affecting the humoral immune system in MS would be a reasonable therapeutic option.

B cells and autoantibodies in the pathogenesis of multiple sclerosis and related inflammatory demyelinating diseases

Multiple sclerosis (MS) is a chronic inflammatory demyelinating disease of the central nervous system (CNS). The mainstream view is that MS is caused by an autoimmune attack of the CNS myelin by myelin-specific CD4 T cells, and this perspective is supported by extensive work in the experimental autoimmune encephalomyelitis (EAE) model of MS as well as immunological and genetic studies in humans. However, it is important to keep in mind that other cell populations of the immune system are also essential in the complex series of events leading to MS, as exemplified by the profound clinical efficacy of B cell depletion with Rituximab. This review discusses the mechanisms by which B cells contribute to the pathogenesis of MS and dissects their role as antigen-presenting cells (APCs) to T cells with matching antigen specificity, the production of proinflammatory cytokines and chemokines, as well as the secretion of autoantibodies that target structures on the myelin sheath and the axon. Mechanistic dissection of the interplay between T cells and B cells in MS may permit the development of B cell based therapies that do not require depletion of this important cell population.

Relevant antibody subsets against MOG recognize conformational epitopes exclusively exposed in solid-phase ELISA

A pathogenic role for circulating anti-myelin antibodies is difficult to establish in multiple sclerosis (MS). Here, we unravel a broad heterogeneity within the anti-myelin oligodendrocyte glycoprotein (MOG) antibodies in humans and non-human primates, and demonstrate that detection of important epitopes of MOG within the pathogenic repertoire is exclusively dependent on presentation on a solid-phase MOG conformer. Results of ELISA and those of a liquid-phase assay were compared using a MOG protein with identical sequence but different conformations. We tested sera from 50 human subjects, plasma of Callithrix jacchus marmosets known to contain antibodies reactive to either conformational or linearized MOG, and monoclonal, conformation-dependent anti-MOG antibodies. We have found no antibody reactivity against the soluble MOG conformer in human serum, and show that this lack of detection is not due to technical artifacts. Rather, dominant epitopes of MOG are not displayed in soluble phase, as shown by a complete lack of binding of conformation-dependent mAb. In MP4-immune marmosets that exhibit demyelinating pathology due to spreading of antibody determinants to myelin-embedded MOG, only ELISA can detect pathogenic circulating anti-MOG antibodies. Thus, the accurate detection of important subsets of pathogenic anti-MOG antibodies requires methods in which MOG is displayed similarly to its natural conformation in myelin.

Anti-myelin antibodies in clinically isolated syndrome indicate the risk of multiple sclerosis in a Swiss cohort

OBJECTIVES

In patients with a clinically isolated syndrome (CIS), the time interval to convert to clinically definite multiple sclerosis (CDMS) is highly variable. Individual and geographical prognostic factors remain to be determined. Whether anti-myelin antibodies may predict the risk of conversion to CDMS in Swiss CIS patients of the canton Berne was the subject of the study.

METHODS

Anti-myelin oligodendrocyte glycoprotein and anti-myelin basic protein antibodies were determined prospectively in patients admitted to our department.

RESULTS

After a mean follow-up of 12 months, none of nine antibody-negative, but 22 of 30 antibody-positive patients had progressed to CDMS. Beta-Interferon treatment delayed the time to conversion from a mean of 7.4 to 10.9 months.

CONCLUSIONS

In a Swiss cohort, antibody-negative CIS patients have a favorable short-term prognosis, and antibody-positive patients benefit from early treatment.

Antimyelin antibodies in clinically isolated syndromes correlate with inflammation in MRI and CSF

OBJECTIVE

We investigated the correlation of antimyelin oligodendrocyte glycoprotein-(anti-MOG) and anti-myelin basic protein antibodies (anti-MBP) in serum of CIS patients with inflammatory signs in MRI and in CSF and, as previously suggested,the incidence of more frequent and rapid progression to clinically definite MS (CDMS).

METHODS

133CIS patients were analysed for anti-MOG and anti-MBP (Western blot). Routine CSF and cranial MRI (quantitatively and qualitatively) measures were analyzed. 55 patients had a follow-up of at least 12 months or until conversion to CDMS.

RESULTS

Patients with anti-MOG and anti-MBP had an increased intrathecal IgG production and CSF white blood cell count(p = 0.048 and p = 0.036). When anti-MBP alone, or both antibodies were present the cranial MRI showed significantly more T2 lesions (p = 0.007 and p = 0.01,respectively). There was a trend for more lesion dissemination in anti-MBP positive patients (p = 0.076).Conversely, anti-MOG- and/or anti-MBP failed to predict conversion to CDMS in our follow-up group (n = 55). Only in female patients with at least one MRI lesion (n = 34) did the presence of anti-MOG correlate with more frequent (p = 0.028) and more rapid (p = 0.0209) transition to CDMS.

CONCLUSIONS

Presence of anti-MOG or anti-MBP or both was not significantly associated with conversion to CDMS in our CIS cohort. However, patients with anti-MOG and anti-MBP had higher lesion load and more disseminated lesions in cranial MRI as well as higher values for CSF leucocytes and intrathecal IgG production. Our data support a correlation of anti-MOG and anti-MBP to inflammatory signs in MRI and CSF. The prognostic value of these antibodies for CDMS, however, seems to be less pronounced than previously reported.

Myelin oligodendrocyte glycoprotein antibodies in pathologically proven multiple sclerosis: frequency, stability and clinicopathologic correlations

Controversy exists regarding the pathogenic or predictive role of anti-myelin oligodendrocyte glycoprotein (MOG) antibodies in patients with multiple sclerosis (MS). Four immunopathological patterns (IP) have been recognized in early active MS lesions, suggesting heterogeneous pathogenic mechanisms. Whether MOG antibodies contribute to this pathological heterogeneity and potentially serve as biomarkers to identify specific pathological patterns is unknown. Here we report the frequencies of antibodies to human recombinant MOG (identified by Western blot and enzyme-linked immunoabsorbent assay (ELISA)) in patients with pathologically proven demyelinating disease, and investigate whether antibody status is associated with clinical course, HLA-DR2-genotype, IP or treatment response to plasmapheresis. The biopsy cohort consisted of 72 patients: 12 pattern I, 43 pattern II and 17 pattern III. No association was found between MOG antibody status and conversion to clinically definite MS, DR-2 status, IP or response to plasmapheresis. There was poor agreement between Western blot and ELISA (kappa = 0.07 for MOG IgM). Fluctuations in antibody seropositivity were seen for 3/4 patients tested serially by Western blot. This study does not support a pathologic pattern-specific role for MOG-antibodies. Variable MOG-antibody status on serial measurements, coupled with the lack of Western blot and ELISA correlations, raises concern regarding the use of MOG-antibody as an MS biomarker and underscores the need for methodological consensus.

Detection of anti-Nogo receptor autoantibody in the serum of multiple sclerosis and controls

OBJECTIVES

A myelin-associated neurite outgrowth inhibitor Nogo-A plays a key role in inhibition of axonal regeneration. Axonal damage beginning at the early stage of multiple sclerosis (MS) is responsible for permanent neurological deficits, although its molecular mechanism remains unknown. The aim was to study the prevalence of autoantibodies against Nogo-A and Nogo receptor (NgR) in the serum of MS.

METHODS

The antibodies were identified in the serum of 30 MS patients, 22 patients with non-MS other neurological diseases (OND), and 22 healthy control (HC) subjects by Western blot using recombinant human Nogo-A-specific segment (NAS), the shared segment of Nogo-A and -B (NAB), Nogo-66 (N66), the non-glycosylated form of NgR, the glycosylated NgR (NgR-Fc), and myelin oligodendrocyte glycoprotein (MOG).

RESULTS

None showed immunoglobulin G (IgG) antibodies against NAS or NAB. In contrast, 30% of MS, 23% of OND and 32% of HC subjects exhibited anti-N66 IgG, while 27% of MS, 27% of OND and 18% of HC showed anti-MOG IgG. None of HC but 33% of MS and 14% of OND showed anti-non-glycosylated NgR IgG. Furthermore, 60% of MS, 18% of OND and 14% of HC showed anti-NgR-Fc IgG.

CONCLUSIONS

Because IgG autoantibodies against N66, NgR and MOG are often detected in the serum of MS and controls, they do not serve as an MS-specific marker.

Lack of association between antimyelin antibodies and progression to multiple sclerosis

BACKGROUND

Patients with a single episode of neurologic dysfunction and brain magnetic resonance imaging (MRI) scans suggestive of multiple sclerosis are at high risk for clinically definite multiple sclerosis, but the outcome for individual patients is unpredictable. An increased risk of progression to clinically definite multiple sclerosis in patients with serum antibodies against myelin oligodendrocyte glycoprotein (MOG) and myelin basic protein (MBP) has been reported.

METHODS

We measured serum anti-MOG and anti-MBP IgG and IgM antibodies in 462 patients with a first clinical event suggestive of multiple sclerosis and at least two clinically silent lesions on brain MRI. The patients were participating in a multicenter trial of treatment with interferon beta-1b. Antibodies were assessed by Western blot analysis at baseline, and the results compared with the time and rate of progression to clinically definite multiple sclerosis or a diagnosis of multiple sclerosis as defined by an international panel (the McDonald criteria). Regular visits were scheduled for the assessment of neurologic impairment and for MRI before treatment and at months 3, 6, 9, 12, 18, and 24.

RESULTS

No associations were found between the presence of anti-MOG and anti-MBP IgM and IgG antibodies and progression to clinically definite multiple sclerosis or a diagnosis of multiple sclerosis according to the McDonald criteria, either in the entire cohort or in any subgroups of the study population.

CONCLUSIONS

Serum antibodies against MOG and MBP, as detected by Western blot analysis, are not associated with an increased risk of progression to clinically definite multiple sclerosis in patients who have had a clinically isolated syndrome suggestive of multiple sclerosis.

Self-antigen tetramers discriminate between myelin autoantibodies to native or denatured protein

The role of autoantibodies in the pathogenesis of multiple sclerosis (MS) and other demyelinating diseases is controversial, in part because widely used western blotting and ELISA methods either do not permit the detection of conformation-sensitive antibodies or do not distinguish them from conformation-independent antibodies. We developed a sensitive assay based on self-assembling radiolabeled tetramers that allows discrimination of antibodies against folded or denatured myelin oligodendrocyte glycoprotein (MOG) by selective unfolding of the antigen domain. The tetramer radioimmunoassay (RIA) was more sensitive for MOG autoantibody detection than other methodologies, including monomer-based RIA, ELISA or fluorescent-activated cell sorting (FACS). Autoantibodies from individuals with acute disseminated encephalomyelitis (ADEM) selectively bound the folded MOG tetramer, whereas sera from mice with experimental autoimmune encephalomyelitis induced with MOG peptide immunoprecipitated only the unfolded tetramer. MOG-specific autoantibodies were identified in a subset of ADEM but only rarely in adult-onset MS cases, indicating that MOG is a more prominent target antigen in ADEM than MS.

Changes in self-reactive IgG antibody repertoire after treatment of experimental autoimmune encephalomyelitis with anti-allergic drugs

We reduced EAE severity by using two anti-allergic drugs. A control group of mice received i.p. injections of PBS as vehicle while a further two groups were treated either with pyrilamine, a histamine receptor 1 antagonist or with CV6209, a platelet activating factor receptor antagonist. Our results showed that the blockade of the responses to both histamine and PAF leads together to a decline in clinical signs of EAE and significant changes in the serum IgG recognition of some healthy brain antigenic targets. We characterized two discriminant antigens: internexin neuronal intermediate filament protein, and malate dehydrogenase 1, which were able to clearly distinguish untreated mice from treated mice. Their role as potent targets in pathogenic and/or neuroprotective processes is discussed.

Clinical relevance of antibodies against myelin oligodendrocyte glycoprotein in different clinical types of multiple sclerosis

OBJECTIVE

Myelin oligodendrocyte glycoprotein (MOG) is a highly immunogenic minor component on the outside surface of CNS myelin which is believed to be one of the autoantigens in multiple sclerosis. The aim of this study was to evaluate the diagnostic potential of anti-MOG IgG antibody levels in cerebrospinal fluid (CSF) and serum of patients with relapsing-remitting multiple sclerosis (RRMS), primary progressive multiple sclerosis (PPMS) and non-inflammatory neurological diseases (NIND) as markers for the different clinical types of multiple sclerosis.

PATIENTS AND METHODS

Consecutive serum and cerebrospinal fluid samples were taken from 21 patients with RRMS, 7 patients with PPMS and 19 patients with NIND. The antibody responses to MOG were determined in paired samples of these different clinical groups by enzyme-linked immunoassay using a recombinant human MOG protein.

RESULTS

The performed analysis indicated that the differences in levels of anti-MOG IgG antibody in serum and cerebrospinal fluid from the patients with RRMS, PPMS or NIND were not statistically significant.

CONCLUSION

The assay is not sensitive or specific enough to be used as a differential diagnostic tool for the clinical types of MS, nor for MS itself.

Immunmodulatorische Stufentherapie der Multiplen Sklerose

The updated recommendations presented here reflect new developments in the diagnostic work-up and immunotherapy of multiple sclerosis (MS) as well as optimization of medical care for MS patients. Monoclonal antibodies provide considerable improvement of treatment, but their use in basic therapy is restricted by their side effect profile. Thus, for the time being, natalizumab is only approved for monotherapy after basic treatment has failed or for rapidly progressive relapsing-remitting MS. In contrast, long-term data on recombinant beta-interferons and glatiramer acetate (Copaxone) show that even after several years no unexpected side effects occur and that a prolonged therapeutic effect can be assumed which correlates with the dose or frequency of treatment. Recently IFN-beta1b (Betaferon) was approved for prophylactic treatment after the first attack (clinically isolated syndrome, CIS). During treatment with beta-interferons, neutralizing antibodies can emerge with possible loss of effectivity. In contrast, antibodies play no role in treatment with glatiramer acetate. During or after therapy with mitoxantrone, serious side effects (cardiomyopathy, acute myeloid leukemia) appeared in 0.2-0.4% of cases. Plasmapheresis is limited to individual curative attempts in escalating therapy of a severe attack. According to the revised McDonald criteria, the diagnosis of MS can be made as early as the occurrence of the first attack (CIS). Recommendations for optimized care of MS patients are also new, thus implementing a resolution of the European Parliament.

Identification of a pathogenic antibody response to native myelin oligodendrocyte glycoprotein in multiple sclerosis

Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system. Although the cause of MS is still uncertain, many findings point toward an ongoing autoimmune response to myelin antigens. Because of its location on the outer surface of the myelin sheath and its pathogenicity in the experimental autoimmune encephalomyelitis model, myelin oligodendrocyte glycoprotein (MOG) is one of the potential disease-causing self antigens in MS. However, the role of MOG in the pathogenesis of MS has remained controversial. In this study we addressed the occurrence of autoantibodies to native MOG and its implication for demyelination and axonal loss in MS. We applied a high-sensitivity bioassay, which allowed detecting autoantibodies that bind to the extracellular part of native MOG. Antibodies, mostly IgG, were found in sera that bound with high affinity to strictly conformational epitopes of the extracellular domain of MOG. IgG but not IgM antibody titers to native MOG were significantly higher in MS patients compared with different control groups with the highest prevalence in primary progressive MS patients. Serum autoantibodies to native MOG induced death of MOG-expressing target cells in vitro. Serum from MS patients with high anti-MOG antibody titers stained white matter myelin in rat brain and enhanced demyelination and axonal damage when transferred to autoimmune encephalomyelitis animals. Overall these findings suggest a pathogenic antibody response to native MOG in a subgroup of MS patients.

Diversified serum IgG response involving non-myelin CNS proteins during experimental autoimmune encephalomyelitis

We sequentially analyzed the serum IgG response against normal mouse brain during experimental autoimmune encephalomyelitis in SJL/J mice injected with CFA, Bordetella pertussis toxin (BPT) and proteolipid protein 139-151 peptide, compared with mice that received CFA and BPT or were uninjected. Dynamic changes were observed from day 0 to day 28 in the 3 groups. Six highly discriminant antigenic bands (kappa=0.974) were identified. Three non-myelin proteins were characterized (mitochondrial aconitase hydratase 2, phosphoglycerate mutase 1, brain specific pyruvate deshydrogenase). The IgG response against two of them was less frequent in EAE whereas it was associated with multiple sclerosis in our previous work.

Serum IgE reactive against small myelin protein-derived peptides is increased in multiple sclerosis patients

Though independent findings suggest roles for the allergic arm of the immune system and myelin-reactive antibodies in MS, myelin-reactive IgE has not been investigated. We have developed a radioimmunoassay that measures reactive IgE, IgG and IgA against short (5-6-mers) myelin protein-derived peptides bearing little to no sequence identity with other human proteins, and which might therefore be targets of a CNS-specific autoimmune attack. Here we show that, irrespective of clinical subtype, MS patients' sera are characterized by a higher frequency of measurable IgE against the peptides. Moreover, in controls with measurable IgE reactive against test peptides, IgG or IgA reactive with the same peptide epitopes is almost always present in vastly greater quantities, whereas in MS subjects peptide-reactive IgA or IgG is often undetectable. The sensitivity of the full assay, when considering overall positive a serum sample that has detectable autoreactive IgE without other competing Igs, is 69% (S.E.: 5%), with a specificity of 87% (S.E.: 9%). We speculate that IgE reactive against CNS target antigens may have both diagnostic and pathogenic significance, particularly if other peptide-specific, potentially blocking Igs are absent.

Antibodies as biological markers for pathophysiological processes in MS

Multiple sclerosis (MS), the most important human inflammatory demyelinating disease of the central nervous system, is characterized by various clinical disease courses, inhomogeneous and unpredictable therapeutic effects, heterogenous genetic backgrounds and immunopathogenetic subtypes as demonstrated by neuropathology. Because of this heterogeneity of MS, a subtyping of our patients by genetical, clinical, neuroradiological, and neuroimmunological parameters will be necessary in the future. Therefore the importance of identifying biological markers for MS has evolved over the past years. Evidence for a possible role of antibodies as biological markers for MS comes from several studies indicating that intrathecal antibody production and the dominance of B cells are associated with a more progressive disease course. In this review we will give an overview on the current status and potential applicability of antibodies as biological markers for the diagnosis, classification, disease activity and prediction of clinical courses in MS. We will therefore summarize the findings on autoantibodies to myelin and nonmyelin antigens and on viral antigens in MS. We believe that antibodies serving as biomarkers will help to establish a differential therapeutic concept in MS, which will allow to treat individuals selectively according to their pathogenetic subtype and disease status.

Myelin flow cytometry assay detects enhanced levels of antibodies to human whole myelin in a subpopulation of multiple sclerosis patients

Antibodies directed against myelin components have been described in multiple sclerosis (MS). Accumulating evidence suggests that pathogenically relevant anti-myelin antibodies bind conformational and post-translationally modified epitopes. However, the current methods to detect anti-myelin antibodies often do not allow recognition of such epitopes. We developed a flow cytometry-based assay to detect antibodies to whole human myelin (including conformational and post-translationally modified epitopes). MS patients (n=152) showed enhanced serum levels of anti-myelin antibodies (total Ig, IgG and IgM) when compared to healthy donors (HD, n=40). Strikingly, approximately 50% of MS patients showed enhanced anti-myelin IgG levels. Anti-myelin IgG levels were not correlated with clinical parameters of disease. In the same population, serum antibody responses to recombinant myelin oligodendrocyte glycoprotein were comparable in MS patients and HD.

Anti-myelin antibodies in multiple sclerosis: clinically useful?

Anti‐myelin antibodies may have predictive clinical value, but striking correlations as reported earlier are unlikely

Antimyelin antibodies and the risk of relapse in patients with a primary demyelinating event

AIM

To investigate whether the presence of serum antibodies against myelin oligodendrocyte glycoprotein (MOG) and myelin basic protein (MBP) in patients with a clinically isolated syndrome (CIS) predicts the interval to develop more frequently and earlier a first relapse (clinically definite multiple sclerosis: CDMS) than seronegative patients.

METHODS

Sera from 45 patients with a CIS and positive intrathecal IgG-synthesis were retrospectively tested for the presence of IgM antibodies against both MOG and MBP. Antibodies were detected by immunoblot using recombinant MOG (1-125) and human MBP antigen preparations. Clinical follow ups were performed retrospectively by telephone interviews and documented neurological examination.

RESULTS

Using the Cox proportional hazards model there was no significant increased risk for developing CDMS in anti-MOG and anti-MBP positive patients compared with negative. However regarding the median of the time span between CIS and CDMS over the whole follow up, antibody positive patients (MOG/MBP +/+) developed significantly earlier relapses (median 5.5 months (range 3-20)) than the antibody negative ones (median 25.0 months (range 7-43); p<0.006). On testing sera from 56 apparently healthy students, quite high frequencies of anti-MOG and anti-MBP antibodies (21% and 28% respectively) were detected. This limited specificity of anti-MOG and anti-MBP antibodies has been seen earlier and restricts their diagnostic relevance in MS despite their role as a predictor of relapses after a CIS.

CONCLUSIONS

This study confirms previous data only in a subanalysis indicating that patients with positive anti-MOG/MBP antibodies develop earlier relapses than patients who are antibody negative. However, the authors could not verify that the presence of these antibodies anticipates the overall risk of developing CDMS-according to study criteria-after a first demyelinating event within the study period of 21-106 months (mean 60 (SD 25)).

Restrictive and diversifying elements of the anti-myelin/oligodendrocyte glycoprotein antibody response in primate experimental allergic encephalomyelitis

Autoantibody responses against conformational epitopes of myelin/oligodendrocyte glycoprotein (MOG) possess myelin destructive potential, as demonstrated in the marmoset model of human multiple sclerosis (MS) and in some rodent models of experimental allergic encephalomyelitis. We have previously characterized monoclonal Fab fragments specific for conformational epitopes of MOG that were derived from a combinatorial antibody library generated from a MOG-immune marmoset. In this paper, we address the molecular heterogeneity of humoral responses against MOG in this outbred model of MS by studying additional antibody clones derived from a genetically unrelated animal. We find that all MOG-specific IgGkappa Fab fragments, unrelated to genetic make-up, utilize a restricted set of variable region genes, IGHV1 and IGHV3 for the H chain and IGKV1, IGKV3, and IGKV5 for the L chain. Despite these restricting factors, diversity within these antibody repertoires can be observed, predominantly within the H-chain CDR3 regions. Our findings suggest that only a limited set of Ig genes is necessary to launch a diverse, destructive humoral immune response against a single CNS antigen in primates. These results are the first to contribute to a better understanding of how myelin-directed and potentially destructive autoantibody responses may develop in human MS.

Epitope specificity of serum antibodies directed against the extracellular domain of myelin oligodendrocyte glycoprotein: Influence of relapses and immunomodulatory treatments

Only few reports are available on the epitope specificity of anti-myelin oligodendrocyte glycoprotein (MOG) antibodies in multiple sclerosis (MS). In the present study we provide a precise characterization of the epitope specificity of serum antibodies directed against the extracellular domain of MOG, including IgG, IgM and IgA immunoglobulin isotypes in 28 relapsing remitting MS patients and report that linear epitopes amino-acid (aa) 37-48 and aa42-53 are immunodominant. Recently experienced relapses intensified the anti-MOG peptide antibody response. Immunomodulatory treatment with interferon-beta or glatiramer-acetate had no major impact on the anti-MOG peptide immunoreactivity after 1 year of therapy.

Antibodies to native myelin oligodendrocyte glycoprotein are serologic markers of early inflammation in multiple sclerosis

Myelin oligodendrocyte glycoprotein (MOG) is an integral membrane protein expressed in CNS oligodendrocytes and outermost myelin lamellae. Anti-MOG Abs cause myelin destruction (demyelination) in animal models of multiple sclerosis (MS); however, such pathogenic Abs have not yet been characterized in humans. Here, a method that specifically detects IgG binding to human MOG in its native, membrane-embedded conformation on MOG-transfected mammalian cells was used to evaluate the significance of these auto Abs. Compared with healthy controls, native MOG-specific IgGs were most frequently found in serum of clinically isolated syndromes (P < 0.001) and relapsing-remitting MS (P < 0.01), only marginally in secondary progressive MS (P < 0.05), and not at all in primary progressive MS. We demonstrate that epitopes exposed in this cell-based assay are different from those exposed on the refolded, extracellular domain of human recombinant MOG tested by solid-phase ELISA. In marmoset monkeys induced to develop MS-like CNS inflammatory demyelination, IgG reactivity against the native membrane-bound MOG is always detected before clinical onset of disease (P < 0.0001), unlike that against other myelin constituents. We conclude that (i) epitopes displayed on native, glycosylated MOG expressed in vivo are early targets for pathogenic Abs; (ii) these Abs, which are not detected in solid-phase assays, might be the ones to play a pathogenic role in early MS with predominant inflammatory activity; and (iii) the cell-based assay provides a practical serologic marker for early detection of CNS autoimmune demyelination including its preclinical stage at least in the primate MS model.

Emergence of antibodies as biomarkers in multiple sclerosis

Rather than being a homogenous disease entity, multiple sclerosis (MS) represents a family of heterogenous inflammatory-demyelinating CNS diseases. The heterogeneity is demonstrated by various well known clinical disease courses and, more importantly, by inhomogenous and unpredictable therapeutic effects. Recent neuropathological evidence has initiated a process of re-evaluation of the immunopathogenetic concepts in MS. The heterogeneity of MS claims to subtype our patients more distinctively in the future by genetic, clinical, neuroradiological and neuroimmunological parameters. Therefore, the importance of identifiying biological markers in MS has evolved over the past few years. This review discusses the current status and potential applicability of antibodies as biological markers for the diagnosis, classification, disease activity and prediction of clinical courses in MS. Antibodies serving as biomarkers will create the future path for establishing a differential therapeutic concept in MS, which will allow the treatment of individuals selectively, according to their pathogenetic subtype and disease status.

Contribution of peptides to multiple sclerosis research

Multiple sclerosis (MS) is an autoimmune disease associated with chronic inflammatory demyelination of the central nervous system in genetically susceptible individuals. Because of the disease complexity and heterogeneity, its pathogenesis remains unknown despite extensive research efforts, and specific effective treatments have not yet been developed. Peptide-based research has been important in attempts to unravel particular aspects of this complex disease, including the characterization of the different molecular mechanisms of MS, with the goal of providing useful products for immune-mediated therapies. In fact, in the past decade, peptide-based research has been predominant in research aimed to identify and/or develop target antigens as synthetic probes for specific biomarkers as well as innovative immunomodulating therapies. This review presents an overview of the contributions of peptide science to MS research and discusses future directions of peptide-based investigations.

Inflammation in white matter: Clinical and pathophysiological aspects

While the central nervous system (CNS) is generally thought of as an immunopriviledged site, immune-mediated CNS white matter damage can occur in both the perinatal period and in adults, and can result in severe and persistent neurological deficits. Periventricular leukomalacia (PVL) is an inflammatory white matter disease of premature infants that frequently results in cerebral palsy (CP). Clinical and experimental studies show that both hypoxic/ischemic and innate immune mechanisms contribute to the destruction of immature oligodendroglia and of axons in the deep cerebral white matter in PVL. No data are yet available as to whether there is any genetic predisposition to PVL or to its neurological sequelae. Multiple sclerosis (MS) is an inflammatory white matter disease that often begins in young adulthood, causes multifocal destruction of mature oligodendroglia and of axons, and eventually leads to substantial cumulative neurological disability. Certain genetic polymorphisms contribute to susceptibility to MS, and adaptive immune responses to myelin-associated self antigens, or to exogenous antigens that mimic these self antigens, play a central role in the pathophysiology of this disease.

Consensus recommendations of the Italian Association for Neuroimmunology for immunochemical cerebrospinal fluid examination

In 2002-2003, the Italian Association for Neuroimmunology (AINI) ran a program for procedure and method standardization in neuroimmunology. The main purposes of the program were: a) to improve the overall quality of analytical performance and, simultaneously, to reduce costs by resource optimization; b) to establish the bases for clinical guidelines in neurology; c) to promote the formation of laboratory networks and of joint research projects; d) to facilitate the procedures for certification required by governmental/non-governmental agencies. This report summarizes the consensus recommendations of a panel of AINI neuroimmunologists/biochemists involved in the field of cerebrospinal fluid examination. The collection process for said recommendations was guided by "impact-factored" literature and the knowledge of the experts involved. Communication was by email and face-to-face at two dedicated AINI workshops.

Antibodies from inflamed central nervous system tissue recognize myelin oligodendrocyte glycoprotein

Autoantibodies to myelin oligodendrocyte glycoprotein (MOG) can induce demyelination and oligodendrocyte loss in models of multiple sclerosis (MS). Whether anti-MOG Abs play a similar role in patients with MS or inflammatory CNS diseases by epitope spreading is unclear. We have therefore examined whether autoantibodies that bind properly folded MOG protein are present in the CNS parenchyma of MS patients. IgG was purified from CNS tissue of 14 postmortem cases of MS and 8 control cases, including cases of encephalitis. Binding was assessed using two independent assays, a fluorescence-based solid-phase assay and a solution-phase RIA. MOG autoantibodies were identified in IgG purified from CNS tissue by solid-phase immunoassay in 7 of 14 cases with MS and 1 case of subacute sclerosing panencephalitis, but not in IgG from noninflamed control tissue. This finding was confirmed with a solution-phase RIA, which measures higher affinity autoantibodies. These data demonstrate that autoantibodies recognizing MOG are present in substantially higher concentrations in the CNS parenchyma compared with cerebrospinal fluid and serum in subjects with MS, indicating that local production/accumulation is an important aspect of autoantibody-mediated pathology in demyelinating CNS diseases. Moreover, chronic inflammatory CNS disease may induce autoantibodies by virtue of epitope spreading.

The glycopeptide CSF114(Glc) detects serum antibodies in multiple sclerosis

Synthetic glycopeptides have the potential to detect antibodies in multiple sclerosis (MS). In the present study, we analyzed the antibodies (IgM class, IgG class and IgG subclasses) to the synthetic glycopeptide CSF114(Glc) in the serum of 186 MS patients, 166 blood donors (BDs), 25 patients affected by meningitis/encephalitis, 41 affected by systemic lupus erythematosus (SLE) and 49 affected by rheumatoid arthritis (RA). The IgM antibody level to CSF114(Glc) was significantly increased in MS patients versus BDs (p<0.001) or versus other autoimmune diseases (SLE or RA, p<0.001). The IgG response was restricted to the subclass IgG2. IgM antibodies to CSF114(Glc) were found in 30% of relapsing/remitting MS patients and, at lower levels, in subjects affected by meningitis/encephalitis. The study of antibodies to CSF114(Glc) is a new, potential immunological marker of MS.

Pathogenic myelin oligodendrocyte glycoprotein antibodies recognize glycosylated epitopes and perturb oligodendrocyte physiology

Antibodies to myelin components are routinely detected in multiple sclerosis patients. However, their presence in some control subjects has made it difficult to determine their contribution to disease pathogenesis. Immunization of C57BL/6 mice with either rat or human myelin oligodendrocyte glycoprotein (MOG) leads to experimental autoimmune encephalomyelitis (EAE) and comparable titers of anti-MOG antibodies as detected by ELISA. However, only immunization with human (but not rat) MOG results in a B cell-dependent EAE. In this study, we demonstrate that these pathogenic and nonpathogenic anti-MOG antibodies have a consistent array of differences in their recognition of antigenic determinants and biological effects. Specifically, substituting proline at position 42 with serine in human MOG (as in rat MOG) eliminates the B cell requirement for EAE. All MOG proteins analyzed induced high titers of anti-MOG (tested by ELISA), but only antisera from mice immunized with unmodified human MOG were encephalitogenic in primed B cell-deficient mice. Nonpathogenic IgGs bound recombinant mouse MOG and deglycosylated MOG in myelin (tested by Western blot), but only pathogenic IgGs bound glycosylated MOG. Only purified IgG to human MOG bound to live rodent oligodendrocytes in culture and, after cross-linking, induced repartitioning of MOG into lipid rafts, followed by dramatic changes in cell morphology. The data provide a strong link between in vivo and in vitro observations regarding demyelinating disease, further indicate a biochemical mechanism for anti-MOG-induced demyelination, and suggest in vitro tools for determining autoimmune antibody pathogenicity in multiple sclerosis patients.

Antibodies against glycosylated native MOG are elevated in patients with multiple sclerosis

Antibodies against native glycosylated myelin-oligodendrocyte-glycoprotein (MOG) were measured by ELISA in patients with multiple sclerosis (MS) and controls. Anti-MOG IgM antibodies were elevated during the first demyelinating event. Higher MOG-specific IgG antibodies were found in patients during relapses and in secondary chronic progressive MS compared to patients in remission and healthy controls. Antibodies against native MOG may be a potential biomarker for MS.

Multiple sclerosis

Multiple sclerosis (MS) is a complex genetic disease associated with inflammation in the central nervous system (CNS) white matter and is thought to be mediated by autoimmune processes. Clonal expansion of B cells, their antibody products, and T cells, hallmarks of inflammation in the CNS, are found in MS. The association of the disease with major histocompatibility complex genes, the inflammatory white matter infiltrates, similarities with animal models, and the observation that MS can be treated with immunomodulatory and immunosuppressive therapies support the hypothesis that autoimmunity plays a major role in the disease pathology. This review discusses the immunopathology of MS with particular focus given to regulatory T cells and the role of B cells and antibodies, immunomodulatory therapeutics, and finally new directions in MS research, particularly new methods to define the molecular pathology of human disease with high-throughput examination of germline DNA haplotypes, RNA expression, and protein structures that will allow the generation of a new series of hypotheses that can be tested to develop better understandings and therapies for this disease.

Immunoadsorption patients with multiple sclerosis: an open-label pilot study

BACKGROUND

Immunoadsorption (IA) is occasionally applied in patients with acute relapses of multiple sclerosis (MS). This pilot study was undertaken to determine whether IA might help in secondary progressive and relapsing-remitting multiple sclerosis.

DESIGN

IA was performed at 1-week intervals in 12 patients with secondary progressive or relapsing-remitting MS. These patients had an extended disability status scale (EDSS) score of 4.5-7 and an EDSS increase of 0.5 within 6 months before inclusion in the study despite conventional drug therapy. The change in the EDSS and that in the MS functional composite (MSFC) score, which consisted of quantitative tests of arm function, ambulation, visual acuity and cognition, served as the primary outcome variables, which were measured at baseline and at 3, 6 and 12 months. Changes in quality of life and cerebral lesions by magnetic resonance imaging (MRI) were also assessed at baseline and after the last immunoadsorption (month 3).

RESULTS

A significant reduction of the median EDSS change was observed after the treatment period, which reversed 3 months after the immunoadsorptions had been stopped. Ten of 12 patients remained stable during the first year of follow-up with no significant changes of the MSFC scores. No significant changes in magnetic resonance imaging T2-hyperintense brain lesions or in the number of gadolinium-positive lesions and in the patients' quality of life were observed. Western blot analyses demonstrated a reduction of serum myelin-specific antibodies, which were collected in the adsorber eluates.

CONCLUSIONS

Removal of immunoglobulins, including myelin-specific antibodies by immunoadsorption, seems to delay disease progression as defined by EDSS, MSFC and MRI, while the patients' quality of life did not deteriorate.

An N-glucosylated peptide detecting disease-specific autoantibodies, biomarkers of multiple sclerosis

Multiple sclerosis (MS) is a complex disease that seems to depend on several pathophysiological processes. Because of its varied clinical presentation, natural history, and response to therapeutic interventions, MS can be considered to be a group of diseases that have not been yet characterized, thus resulting in difficult evaluation of prognosis. In the last few years, the role of autoAbs in MS has been reevaluated, and, therefore, their identification as specific biomarkers became a relevant target. In this paper, we demonstrate that an aberrant N-glucosylation is a fundamental determinant of autoAb recognition in MS. Thus, we developed CSF114(Glc), an antigenic probe accurately measuring IgM autoAbs in the sera of a patient population, as disease biomarker. The relevance of CSF114(Glc) is demonstrated by its clinical application and correlation with disease activity and prognosis. In fact, CSF114(Glc), a structure-based designed glycopeptide, is able to recognize, by ELISA, the presence of specific IgM autoAbs in the sera of a MS patient population but not in blood donors and other autoimmune conditions. AutoAbs specific for CSF114(Glc) isolated from MS patients recognized myelin and oligodendrocyte antigens by immunohistochemistry but not other nonrelevant tissues. We demonstrate that CSF114(Glc) is a reliable, specific probe in a longitudinal study of untreated MS patients. Development of IgG/IgM anti-CSF114(Glc) Abs paralleled clinical activity and brain lesions positive to MRI. Therefore, a CSF114(Glc)-based immunoassay on sera may have important prognostic value in monitoring MS disease progression guiding optimal therapeutic treatment.

Multiple sclerosis – novel insights and new therapeutic strategies

PURPOSE OF REVIEW

This review focuses on novel aspects of the pathogenesis and advances in the therapy of multiple sclerosis (MS).

RECENT FINDINGS

Recent observations suggest that early lesion development in MS may start in some forms with oligodendrocyte death and that inflammation appears as a secondary phenomenon only. The lack of sufficient remyelination in MS may be the result of a disturbed function of basic helix-loop-helix transcription factors. Clinically the identification of patients with a clinically isolated syndrome at high risk to develop clinically definite MS remains difficult; the predictive value of serum antibodies against myelin proteins remains controversial. The role of neutralizing antibodies in interferon therapy is discussed. New therapeutic approaches in MS are emerging.

SUMMARY

The existing view on the pathogenesis of MS is still changing. The original assumption that cell-mediated demyelination is the key event in lesion development dictating clinical disability is critically reviewed and alternative pathways have been suggested. Oligodendrocyte death, axonal loss, the role of CD8 T lymphocytes, T regulatory cells, and B lymphocytes have come into the focus of newly evolving concepts in MS pathogenesis. A deepened understanding of the immunopathogenesis of this disease translates into innovative therapeutic approaches, such as blockade of alpha4 integrins by a humanized monoclonal antibody. In various animal models cell-replacement strategies yield promising results; however, turning these findings into an effective therapy in MS patients has a long way to go.

New insights into cell responses involved in experimental autoimmune encephalomyelitis and multiple sclerosis

Animal models of autoimmune diseases such as experimental autoimmune encephalomyelitis (EAE) are inflammatory demyelinating diseases which comprise a heterogeneous group of disorders that affect the peripheral and central nervous systems. EAE presents close similarities with multiple sclerosis (MS), a chronic inflammatory disease affecting central nervous system (CNS) white matter. Many studies have shown EAE to be a particularly useful animal model for the understanding of both the mechanisms of immune-mediated CNS pathology and the progressive clinical course of multiple sclerosis. Previous data has underlined the importance of CD4+ T cell involvement in mediating the autoimmune processes associated with the destruction of myelin and the role of the T helper 1 (Th1) pattern of cytokine secretion. However, EAE studies have also demonstrated that other cells involved in innate and/or adaptive immune responses may also play a critical role in the early and progressive events of the immune reaction leading to inflammation and CNS damage. In this review, we present such new data and discuss their potent implication for future new therapeutical approaches.