Improving the sensitivity of myelin oligodendrocyte glycoprotein-antibody testing: exclusive or predominant MOG-IgG3 seropositivity-a potential diagnostic pitfall in patients with MOG-EM/MOGAD.

BACKGROUND: Myelin oligodendrocyte glycoprotein antibody-associated encephalomyelitis (MOG-EM; also termed MOG antibody-associated disease, MOGAD) is the most important differential diagnosis of both multiple sclerosis and neuromyelitis optica spectrum disorders. A recent proposal for new diagnostic criteria for MOG-EM/MOGAD explicitly recommends the use of immunoglobulin G subclass 1 (IgG1)- or IgG crystallizable fragment (Fc) region-specific assays and allows the use of heavy-and-light-chain-(H+L) specific assays for detecting MOG-IgG. By contrast, the utility of MOG-IgG3-specific testing has not been systematically evaluated. OBJECTIVE: To assess whether the use of MOG-IgG3-specific testing can improve the sensitivity of MOG-IgG testing. METHODS: Re-testing of 22 patients with a definite diagnosis of MOG-EM/MOGAD and clearly positive MOG-IgG status initially but negative or equivocal results in H+L- or Fc-specific routine assays later in the disease course (i.e. patients with spontaneous or treatment-driven seroreversion). RESULTS: In accordance with previous studies that had used MOG-IgG1-specific assays, IgG subclass-specific testing yielded a higher sensitivity than testing by non-subclass-specific assays. Using subclass-specific secondary antibodies, 26/27 supposedly seroreverted samples were still clearly positive for MOG-IgG, with MOG-IgG1 being the most frequently detected subclass (25/27 [93%] samples). However, also MOG-IgG3 was detected in 14/27 (52%) samples (from 12/22 [55%] patients). Most strikingly, MOG-IgG3 was the predominant subclass in 8/27 (30%) samples (from 7/22 [32%] patients), with no unequivocal MOG-IgG1 signal in 2 and only a very weak concomitant MOG-IgG1 signal in the other six samples. By contrast, no significant MOG-IgG3 reactivity was seen in 60 control samples (from 42 healthy individuals and 18 patients with MS). Of note, MOG-IgG3 was also detected in the only patient in our cohort previously diagnosed with MOG-IgA+/IgG- MOG-EM/MOGAD, a recently described new disease subvariant. MOG-IgA and MOG-IgM were negative in all other patients tested. CONCLUSIONS: In some patients with MOG-EM/MOGAD, MOG-IgG is either exclusively or predominantly MOG-IgG3. Thus, the use of IgG1-specific assays might only partly overcome the current limitations of MOG-IgG testing and-just like H+L- and Fcγ-specific testing-might overlook some genuinely seropositive patients. This would have potentially significant consequences for the management of patients with MOG-EM/MOGAD. Given that IgG3 chiefly detects proteins and is a strong activator of complement and other effector mechanisms, MOG-IgG3 may be involved in the immunopathogenesis of MOG-EM/MOGAD. Studies on the frequency and dynamics as well as the clinical and therapeutic significance of MOG-IgG3 seropositivity are warranted.

[MOG encephalomyelitis: international recommendations on diagnosis and antibody testing]. / MOG-Enzephalomyelitis: Internationale Empfehlungen zu Diagnose und Antikörpertestung.

Over the past few years, new-generation cell-based assays have demonstrated a robust association of autoantibodies to full-length human myelin oligodendrocyte glycoprotein (MOG-IgG) with (mostly recurrent) optic neuritis, myelitis and brainstem encephalitis, as well as with acute disseminated encephalomyelitis (ADEM)-like presentations. Most experts now consider MOG-IgG-associated encephalomyelitis (MOG-EM) a disease entity in its own right, immunopathogenetically distinct from both classic multiple sclerosis (MS) and aquaporin-4 (AQP4)-IgG-positive neuromyelitis optica spectrum disorders (NMOSD). Owing to a substantial overlap in clinicoradiological presentation, MOG-EM was often unwittingly misdiagnosed as MS in the past. Accordingly, increasing numbers of patients with suspected or established MS are currently being tested for MOG-IgG. However, screening of large unselected cohorts for rare biomarkers can significantly reduce the positive predictive value of a test. To lessen the hazard of overdiagnosing MOG-EM, which may lead to inappropriate treatment, more selective criteria for MOG-IgG testing are urgently needed. In this paper, we propose indications for MOG-IgG testing based on expert consensus. In addition, we give a list of conditions atypical for MOG-EM ("red flags") that should prompt physicians to challenge a positive MOG-IgG test result. Finally, we provide recommendations regarding assay methodology, specimen sampling and data interpretation, and propose for the first time diagnostic criteria for MOG-EM.

[Neuroimmunology and rheumatology: overlap and differential diagnoses]. / Neuroimmunologie und Rheumatologie: Schnittmengen und Differenzialdiagnosen.

Multiple sclerosis (MS) and neuromyelitis optica spectrum disorder (NMOSD) are chronic inflammatory diseases of the central nervous system (CNS). They may cause inflammation in the brain, spinal cord and optic nerve. Both conditions must be differentiated from CNS manifestations of other systemic autoimmune diseases such as systemic lupus erythematosus (SLE), Sjögren's syndrome, autoinflammtory diseases and sarcoidosis, since amongst others myelitis and optic nerve inflammation may also occur in these conditions. Nevertheless, coexistence of MS or NMOSD with rheumatic disorders such as SLE or Sjögren's syndrome has also been reported especially in NMOSD. Since the therapeutic approach is different it is important to determine a clear diagnosis. In addition some drugs used in rheumatic disease such as anti-tumor necrosis factor biologics may induce inflammatory disease of the CNS and should be avoided in MS. An interdisciplinary approach between neuroimmunology and rheumatology is important for optimal care and treatment in such patients.

MOG encephalomyelitis: international recommendations on diagnosis and antibody testing.

Over the past few years, new-generation cell-based assays have demonstrated a robust association of autoantibodies to full-length human myelin oligodendrocyte glycoprotein (MOG-IgG) with (mostly recurrent) optic neuritis, myelitis and brainstem encephalitis, as well as with acute disseminated encephalomyelitis (ADEM)-like presentations. Most experts now consider MOG-IgG-associated encephalomyelitis (MOG-EM) a disease entity in its own right, immunopathogenetically distinct from both classic multiple sclerosis (MS) and aquaporin-4 (AQP4)-IgG-positive neuromyelitis optica spectrum disorders (NMOSD). Owing to a substantial overlap in clinicoradiological presentation, MOG-EM was often unwittingly misdiagnosed as MS in the past. Accordingly, increasing numbers of patients with suspected or established MS are currently being tested for MOG-IgG. However, screening of large unselected cohorts for rare biomarkers can significantly reduce the positive predictive value of a test. To lessen the hazard of overdiagnosing MOG-EM, which may lead to inappropriate treatment, more selective criteria for MOG-IgG testing are urgently needed. In this paper, we propose indications for MOG-IgG testing based on expert consensus. In addition, we give a list of conditions atypical for MOG-EM ("red flags") that should prompt physicians to challenge a positive MOG-IgG test result. Finally, we provide recommendations regarding assay methodology, specimen sampling and data interpretation.

MOG-IgG in primary and secondary chronic progressive multiple sclerosis: a multicenter study of 200 patients and review of the literature.

BACKGROUND: Antibodies to human full-length myelin oligodendrocyte glycoprotein (MOG-IgG) as detected by new-generation cell-based assays have recently been described in patients presenting with acute demyelinating disease of the central nervous system, including patients previously diagnosed with multiple sclerosis (MS). However, only limited data are available on the relevance of MOG-IgG testing in patients with chronic progressive demyelinating disease. It is unclear if patients with primary progressive MS (PPMS) or secondary progressive MS (SPMS) should routinely be tested for MOG-IgG. OBJECTIVE: To evaluate the frequency of MOG-IgG among patients classified as having PPMS or SPMS based on current diagnostic criteria. METHODS: For this purpose, we retrospectively tested serum samples of 200 patients with PPMS or SPMS for MOG-IgG using cell-based assays. In addition, we performed a review of the entire English language literature on MOG-IgG published between 2011 and 2017. RESULTS: None of 139 PPMS and 61 SPMS patients tested was positive for MOG-IgG. Based on a review of the literature, we identified 35 further MOG-IgG tests in patients with PPMS and 55 in patients with SPMS; the only reportedly positive sample was positive just at threshold level and was tested in a non-IgG-specific assay. In total, a single borderline positive result was observed among 290 tests. CONCLUSION: Our data suggest that MOG-IgG is absent or extremely rare among patients with PPMS or SPMS. Routine screening of patients with typical PPMS/SPMS for MOG-IgG seems not to be justified.

[Current aspects of therapy conversion for multiple sclerosis]. / Aktuelles zur Therapieumstellung bei Multipler Sklerose.

In recent years the approval of new substances has led to a substantial increase in the number of course-modifying immunotherapies available for multiple sclerosis. Therapy conversion therefore represents an increasing challenge. The treatment options sometimes show complex adverse effect profiles and necessitate a long-term and comprehensive monitoring. This article presents an overview of therapy conversion of immunotherapies for multiple sclerosis in accordance with the recommendations of the Disease-Related Competence Network for Multiple Sclerosis and the German Multiple Sclerosis Society as well as the guidelines on diagnostics and therapy for multiple sclerosis of the German Society of Neurology and the latest research results. At the present point in time it should be noted that no studies have been carried out for most of the approaches for therapy conversion given here; however, the recommendations are based on theoretical considerations and therefore correspond to recommendations at the level of expert consensus, which is currently essential for the clinical daily routine.

CCR5 expression on macrophages/microglia is associated with early remyelination in multiple sclerosis lesions.

Remyelination in multiple sclerosis (MS) occurs spontaneously and extensively. The underlying mechanisms, however, are only partly understood. Findings in experimental animal settings suggest that inflammation promotes remyelination and repair. Here, we characterized the chemokine receptor expression profiles of macrophages/microglia in early remyelinating and completely remyelinated lesions compared with active demyelinating and inactive demyelinated MS lesions obtained in the early disease course. Biopsy material consisting of 16 MS cases was available for this study. We found that macrophages/microglia within early remyelinating lesions expressed predominantly CCR5. Our findings implicate a possible role of CCR5(+) cells in initiating remyelination.

Expression of chemokine receptors on peripheral blood mononuclear cells of patients with immune-mediated neuropathies treated with intravenous immunoglobulins.

Intravenous immunoglobulin (IVIg) is an efficacious treatment for immune-mediated neuropathies like Guillain-Barré syndrome (GBS), chronic inflammatory demyelinating neuropathy (CIDP), and multifocal motor neuropathy (MMN). In the pathogenesis of immune-mediated neuropathies chemokines and their receptors play a crucial role. Using flow cytometry we examined whether IVIg modulates chemokine expression repertoires of T cells and monocytes. The expression of inflammatory chemokine receptors CCR1, CCR2, CCR4, CCR5, CCR6 and CXCR3 was investigated on circulating T-cell subsets, and CCR1, CCR2 and CCR5 on circulating monocytes before and after IVIg treatment in patients with immune-mediated neuropathies (MMN, n = 7; GBS, n = 1; CIDP, n = 2). Furthermore, the homing potential of T cells was analyzed by the expression of CCR7, a chemokine receptor known to be utilized by mature T cells to recirculate into secondary lymphoid organs. In contrast to studies in chronic heart failure, no differences in expression patterns before and after IVIg treatment of any of the investigated chemokine receptors were found. Furthermore, the proportion of CD45RO-positive CD4+ or CD8+ T-cell subsets was not changed by IVIg treatment. Thus, we concluded that modulation of the expression of chemokine receptors on circulating leukocytes by IVIg is not a mode of action in immune-mediated neuropathies.

Blockade of chemokine signaling in patients with multiple sclerosis.

We assessed the safety and efficacy of orally administered CC chemokine receptor 1 (CCR1) antagonist in 105 patients with relapsing/remitting MS (RRMS) in a 16-week, randomized, double-blind, placebo-controlled trial. The primary endpoint was the cumulative number of newly active lesions on serial MRI scans. Other MRI, immunologic, and clinical outcomes were also explored. No significant treatment difference was observed for any tested MRI variable. CCR1 does not contribute to initial leukocyte infiltration in RRMS.

Monoaminergic neurotransmission is altered in hepatitis C virus infected patients with chronic fatigue and cognitive impairment.

BACKGROUND: The majority of patients with hepatitis C virus (HCV) infection suffer from disabling fatigue, cognitive dysfunction, and quality of life reduction. Meanwhile, there is increasing evidence that HCV infection can affect brain function. Recent studies have shown that fatigue and psychomotor slowing may resolve in patients with hepatitis C after treatment with ondansetron. This observation indicates alteration of serotonergic neurotransmission in HCV infected patients with chronic fatigue. METHODS: Data from 20 HCV infected patients who were referred to our clinic because of disabling fatigue and cognitive decline of unknown cause were analysed retrospectively. Patients had undergone a diagnostic programme, including clinical and psychometric examination, electroencephalogram (EEG), magnetic resonance imaging of the brain, cerebrospinal fluid analysis, and I-123-beta-CIT (2beta-carbomethoxy-3-beta-(4-[(123)I]iodophenyl)tropane) single photon emission computerised tomography (SPECT) studies of serotonin and dopamine transporter binding capacity. RESULTS: All patients had pathological results on the fatigue impact scale. Two thirds of patients showed pathological attention test results. EEG, magnetic resonance imaging, and cerebrospinal fluid analysis were normal. Pathological dopamine transporter binding was present in 12/20 (60%) patients and pathological serotonin transporter binding in 8/19 (50%) patients. Patients with normal SPECT results did not significantly differ from controls with regard to psychometric test results. Interestingly, patients with both decreased serotonin and dopamine transporter binding showed significantly impaired performance in most of the tests applied. Comorbidity that could have impaired cerebral function was excluded in all patients. CONCLUSION: Our findings indicate alteration of serotonergic and dopaminergic neurotransmission in HCV infected patients with chronic fatigue and cognitive impairment.

Promotion of remyelination by immunoglobulins: implications for the treatment of multiple sclerosis.

During the last decade immunomodulatory treatments have been shown to influence the natural course of multiple sclerosis (MS). However, demyelination in the central nervous system (CNS) still occurs and repair mechanisms are incomplete leading to neurological deficits. Currently, there is no therapy available to promote remyelination and thus enhance repair mechanisms. Both immunoglobulins directed against spinal cord homogenate and polyclonal immunoglobulins for intravenous use (IVIg) have been shown to support remyelination in the animal model of Theiler's virus encephalomyelitis (TMEV). Further studies have identified monoclonal antibodies that lead to remyelination in TMEV and a toxic demyelination model using lysolecithin. The shared characteristics of these monoclonal antibodies are an IgM isotype and the capacity to bind oligodendrocytes, independent of epitope specificity. Recently, two human monoclonal antibodies with remyelinating properties were described. Clinical trials with IVIg have so far failed to demonstrate clinical improvement in MS patients, but these studies only employed IgG preparations. However, recent experimental data both in vivo and in vitro underline the importance of IgM for remyelination. Thus future clinical trials are needed to evaluate the remyelination potential of IgM in human diseases. The design of monoclonal antibodies capable of promoting remyelination is a telling example for the design of new specific therapies derived from biological products like polyclonal immunoglobulins.

[Concepts of lesion development in multiple sclerosis. Current approaches and clinical-therapeutic implications ]. / Konzepte zur Läsionsentstehung bei Multipler Sklerose. Aktueller Diskussionsstand und klinisch-therapeutische Implikationen.

The pathogenesis and development of lesions in multiple sclerosis (MS) are still unexplained and are the subject of some controversy. On the basis of histopathological analysis of a small set of MS cases, a recently published study postulates primary oligodendroglial damage as the initiator of MS lesions, with infiltration of leukocytes into the central nervous system (CNS) as a secondary phenomenon. In this paper we outline the current controversial discussion and different concepts of lesion development in MS. We conclude that demyelination can result from different pathogenic mechanisms, with either primary autoimmune inflammation or primary oligodendroglial damage and a secondary inflammatory reaction. Lesions can be divided into four subtypes (patterns I-IV) on the basis of histopathological characteristics, which supports the idea that MS lesions develop in different ways. These new aspects may have major implications for treatment. However, except in a few specific forms, most MS patients cannot currently be assigned to one of these lesion subtypes by means of clinical and paraclinical parameters. Without this, individual treatments tailored to the pathogenesis will not be possible.

[Cannabinoids in multiple sclerosis -- therapeutically reasonable?]. / Cannabinoide bei Multipler Sklerose -- therapeutisch sinnvoll?

For centuries extracts from the Cannabis sativa plant have been used for recreational use and as remedies. Anecdotal reports from patients with multiple sclerosis (MS) experiencing relief of their spasticity and pain after smoking marihuana have prompted discussions about a potential therapeutic application of cannabis preparations in MS. Only recently the first large, multicenter, double-blind, placebo controlled study was conducted evaluating the use of cannabinoids for treatment of spasticity and other symptoms related to MS. Based on this trial and previous uncontrolled observations together with insights from basic research and animal experiments there is reasonable evidence for the therapeutical employment of cannabinoids in the treatment of MS related symptoms. Furthermore, data are arising that cannabinoids have immunomodulatory and neuroprotective properties. However, results from clinical trials do not allow the recommendation for the general use of cannabinoids in MS. This article summarizes the present knowledge of clinical and experimental research regarding the therapeutic potential of cannabinoids for the treatment of MS.

Interferon-beta up-regulates the expression of co-stimulatory molecules CD80, CD86 and CD40 on monocytes: significance for treatment of multiple sclerosis.

Interferon (IFN)-beta reduces the biological activity of multiple sclerosis (MS), a presumably T cell-mediated autoimmune disease of central nervous system (CNS) myelin. Co-stimulatory molecules are necessary for full T cell activation and differential expression of co-stimulatory molecules on antigen-presenting cells is thought to influence the type of effector T cell response (Th1/Th2). In this study we investigated the effects of IFN-beta on the expression of co-stimulatory molecules on lymphocytes and monocytes as a potential mechanism of action of IFN-beta in MS. Peripheral blood mononuclear cells (PBMCs) were stimulated with IFN-beta in vitro and expression of CD80, CD86, CD40 and HLA was examined by flow cytometry and reverse-transcription polymerase chain reaction. Whereas IFN-beta had no effect on the expression of these molecules on T and B lymphocytes there was a significant increase on monocytes. Correspondingly, the expression of mRNA increased after 6-18 h. This in vitro response was also observed in untreated MS patients and patients receiving treatment with IFN-beta. The increase of co-stimulatory molecules on monocytes was not mediated by interleukin (IL)-10. When IFN-beta-stimulated monocytes were used to stimulate autologous T cells an increased secretion of IL-13 was observed. In biopsies taken from IFN-beta-induced skin reactions after subcutaneous injection increased expression of CD80 mRNA was detected, indicating that IFN-beta also up-regulates this co-stimulatory molecule in vivo. These data provide the background for further studies of IFN-beta-induced changes of co-stimulatory molecules in MS patients.

Chemokine receptors on infiltrating leucocytes in inflammatory pathologies of the central nervous system (CNS).

Haematogenous leucocytes enter the central nervous system (CNS) during diverse disorders of varied aetiologies. Understanding the trafficking cues that mediate CNS leucocyte infiltration might promote the development of flexible and selective means to modulate inflammation to achieve clinical benefit. The trafficking machinery of leucocytes has been elucidated during the past decade and consists of cell-surface adhesion molecules, chemoattractant cytokines (chemokines) and their receptors. Recent work in our laboratory characterized chemokine receptors found on T lymphocytes and monocytes in brain sections from subjects with one pathological subtype of multiple sclerosis (MS), an immune-mediated inflammatory demyelinating disease. In these tissues, the types 1 and 5 CC chemokine receptors (CCR1 and CCR5) were detected on perivascular monocytic cells whereas only CCR5 was present on parenchymal macrophages. The type 3 CXC chemokine receptor (CXCR3) was present on virtually all CD3-positive T cells. In the current study, we evaluated the expression of these receptors on the infiltrating cells present in cases of other inflammatory CNS disorders including those of dysimmune, infectious, neoplastic, and vascular aetiology. Perivascular and parenchymal monocytic cells expressed CCR1 in all cases and CXCR3 was consistently present on a substantial proportion of CD3+ T cells. The occurrence of CCR5 on parenchymal macrophages was much less uniform across the varied disorders. These data implicate CCR1 in monocyte infiltration of the CNS and are consistent with reports of studies in CCR1-deficient mice. CXCR3 is also likely to play a role in accumulation of T cells in the inflamed CNS. By contrast, our findings suggest that regulation of CCR5 on phagocytic macrophages may be contingent on the lesion environment.

[Chemokine--possible new options for the treatment of multiple sclerosis]. / Chemokine. Neue Therapieansätze für die Multiple Sklerose?

Accumulation and activation of mononuclear cells (lymphocytes and monocytes) in the CNS is one of the crucial steps in the pathogenesis of multiple sclerosis (MS). Chemokines and their receptors govern physiological and pathological leukocyte trafficking and may also be pertinent in hematogenous leukocyte infiltration of the CNS. Due to broad pharmacological interest in the chemokine system, peptide antagonists and small molecular antagonists are now available for clinical therapeutic trials. For the treatment of MS in particular, the chemokine receptors CCR1, CCR2, CCR5, and CXCR3 are possible targets in a chemokine-based therapeutic approach. In this review, we summarize current knowledge of the roles of chemokines and chemokine receptors in the pathogenesis of MS. Furthermore, options for possible therapeutic intervention through the chemokine system are outlined. Clinical studies in MS patients applying this knowledge are expected soon.

T-cells in the cerebrospinal fluid express a similar repertoire of inflammatory chemokine receptors in the absence or presence of CNS inflammation: implications for CNS trafficking.

It is believed that chemokines and their receptors are involved in trafficking of T-cells to the central nervous system (CNS). The aim of the current study was to define the expression on cerebrospinal fluid (CSF) T-cells of six chemokine receptors associated with trafficking to sites of inflammation. Flow cytometry was used to detect chemokine receptor expression. We observed that CD3+T-cells in the CSF express a restricted array of inflammatory chemokine receptors, specifically CXCR3, CCR5 and CCR6, but little CCR1-3. This repertoire was independent of the presence of CNS inflammation, since comparable findings were obtained in patients with multiple sclerosis (MS) and individuals with non-inflammatory neurological diseases. The enrichment of CCR5+T-cells in the CSF could largely be explained by higher frequency of CD4+/CD45RO+T-cells in this compartment. In contrast, CD4+/CD45RO+T-cells expressing CXCR3 were significantly enriched in CSF as compared with blood. Similar levels of CCR6+/CD3+T-cells were observed in blood and CSF, while levels of CCR2+/CD3+T-cells were lower in CSF than in blood. The CSF was virtually devoid of CCR5+/CXCR3- T-cells, suggesting that the expression of CCR5 alone is not sufficient for the trafficking of CD3+T-cells to the CSF. We hypothesize that CXCR3 is the principal inflammatory chemokine receptor involved in intrathecal accumulation of T-cells in MS. Through interactions with its ligands, CXCR3 is proposed to mediate retention of T-cells in the inflamed CNS.