The current status of multiple sclerosis intra-blood-brain-barrier IgG synthesis

Analysis of Predictive Risk Factors in Aquaporin-4-IgG Positive Highly Active Neuromyelitis Optica Spectrum Disorders

Neuromyelitis optica spectrum disorders (NMOSDs) are inflammatory diseases with a high risk of recurrence and progressive disability, and it is crucial to find sensitive and reliable biomarkers for prognosis and the early prediction of relapse. Highly active NMOSD is defined as two or more clinical relapses within a 12-month period. In this study, we analyzed independent risk factors among patients with aquaporin-4 (AQP4)-IgG positive highly active NMOSD. In this retrospective study, we analyzed the data of 94 AQP4-IgG positive patients with highly active NMOSD and 105 AQP4-IgG positive controls with non-highly active NMOSD. In order to rule out possible effects of previous treatments (such as glucocorticoids, immunoglobulin, and immunosuppressants), we focused on the first-attack NMOSD patients admitted to our hospital. Clinical data, including the age of onset, gender, comorbidities, and serum analysis and cerebrospinal fluid (CSF) analysis results, were collected, after which logistic regression models were used to determine the associations between the clinical factors and relapse outcomes. The prevalence of connective tissue disease and the proportion of antinuclear antibody (ANA)-positivity were higher in the highly active NMOSD group than in the control group. The leukocyte counts, homocysteine (Hcy) levels, CSF leukocyte counts, protein concentrations, IgG indexes, and 24h IgG synthesis rates were also higher in the highly active NMOSD group. The results of multivariate analysis indicated that connective tissue disease comorbidity (OR = 5.953, 95% CI: 1.221–29.034, P = 0.027), Hcy levels (OR = 1.063, 95% CI: 1.003–1.126, P = 0.04), and 24h IgG synthesis rate (OR = 1.038, 95% CI: 1.003–1.075, P = 0.034) may be independent risk factors for AQP4-IgG positive highly active NMOSD relapse after adjusting for various variables. Comorbidity of connective tissue disease, Hcy levels, and 24h IgG synthesis rate may be independent risk factors for AQP4-IgG positive highly active NMOSD.

Developing Biomarkers for MS

Existing clinical outcomes of disease activity, including relapse rates, are inherently insensitive to the underlying pathological process in MS. Moreover, it is extremely difficult to measure clinical disability in patients, which is often a retrospective assessment, and definitely not within the time frame of a clinical trial. Biomarkers , conversely are more specific for a pathologic process and if used correctly can prove invaluable in the diagnosis, stratification and monitoring of disease activity, including any subclinical activity which is not visible to the naked eye. In this chapter, we discuss the development of neurofilaments as surrogate outcomes of disability in MS. The validation and qualification are vital steps in biomarker development and to gaining acceptance in scientific community, and the pitfalls leading up to this are also discussed.

Novel myelin penta- and hexa-acetyl-galactosyl-ceramides: structural characterization and immunoreactivity in cerebrospinal fluid

Fast migrating cerebrosides (FMC) are derivatives of galactosylceramide (GalCer). The structures of the most hydrophobic FMC-5, FMC-6, and FMC-7 were determined by electrospray ionization linear ion-trap mass spectrometry (MS) and nuclear magnetic resonance (NMR) spectroscopy complementing previous NMR spectroscopy and gas chromatography-mass spectrometry to be 3-O-acetyl-sphingosine-GalCer derivatives with galactose O-acetyl modifications. FMC-5 and FMC-6 are 3-O-acetyl-sphingosine-2,3,4,6-tetra-O-acetyl-GalCer with nonhydroxy and hydroxy-N-fatty-acids, while FMC-7 has an additional O-acetylation of the 2-hydroxy-fatty acid. The immuno-reactivity in human cerebrospinal fluid (CSF) to these acetylated glycolipids was examined in central nervous system (CNS) infectious disease, noninflammatory disorders, and multiple sclerosis (MS). Screening for lipid binding in MS and other neurological disease groups revealed that the greatest anti-hydrophobic FMC reactivity was observed in the inflammatory CNS diseases (meningitis, meningo-encephalitis, and subacute sclerosing panencephalitis). Some MS patients had increased reactivity with the hydrophobic FMCs and with glycoglycerophospholipid MfGL-II from Mycoplasma fermentans. The cross-reactivity of highly acetylated GalCer with microbial acyl-glycolipid raises the possibility that myelin-O-acetyl-cerebrosides, bacterial infection, and neurological disease are linked.

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.

Vaccines for multiple sclerosis: progress to date

Multiple sclerosis (MS) is an inflammatory demyelinating disease of the CNS, characterized pathologically by a perivascular infiltrate consisting predominantly of T cells and macrophages. Although its aetiology remains unknown, several lines of evidence support the hypothesis that autoimmune mechanisms play a major role in the development of the disease. Several widely used disease-modifying agents are approved for the treatment of MS. However, these agents are only partially effective and their ability to attenuate the more progressive phases of the disease is not clear at this time. Therefore, there is a need to develop improved treatment options for MS. This article reviews the role of several novel, selective vaccine strategies that are currently under investigation, including: (i) T-cell vaccination (TCV); (ii) T-cell receptor (TCR) peptide vaccination; (iii) DNA vaccination; and (iv) altered peptide ligand (APL) vaccination. The administration of attenuated autoreactive T cells induces regulatory networks to specifically suppress pathogenic T cells in MS, a strategy named TCV. The concept of TCV was based on the experience of vaccination against aetiological agents of infectious diseases in which individuals are purposely exposed to an attenuated microbial pathogen, which then instructs the immune system to recognize and neutralize it in its virulent form. In regard to TCV, attenuated, pathogenic T cells are similarly used to instruct the immune system to recognize and neutralize disease-inducing T cells. In experimental allergic encephalomyelitis (EAE), an animal model for MS, pathogenic T cells use a strikingly limited number of variable-region elements (V region) to form TCR specific for defined autoantigens. Thus, vaccination with peptides directed against these TCR structures may induce immunoregulatory mechanisms, thereby preventing EAE. However, unlike EAE, myelin-reactive T cells derived from MS patients utilize a broad range of different V regions, challenging the clinical utility of this approach. Subsequently, the demonstration that injection of plasmid DNA encoding a reporter gene into skeletal muscle results in expression of the encoded proteins, as well as in the induction of immune responses in animal models of autoimmunity, was explored as another strategy to re-establish self-tolerance. This approach has promise for the treatment of MS and, therefore, warrants further investigation. APLs are molecules in which the native encephalitogenic peptides are modified by substitution(s) of one or a few amino acids critical for contact with the TCR. Depending on the substitution(s) at the TCR contact residues of the cognate peptide, an APL can induce immune responses that can protect against or reverse EAE. However, the heterogeneity of the immune response in MS patients requires further study to determine which patients are most likely to benefit from APL therapy. Other potential approaches for vaccines in MS include vaccination against axonal growth inhibitors associated with myelin, use of dendritic cells pulsed with specific antigens, and active vaccination against proinflammatory cytokines. Overall, vaccines for MS represent promising approaches for the treatment of this devastating disease, as well as other autoimmune diseases.

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.

Interferon-beta treatment for multiple sclerosis

Multiple sclerosis (MS) is the leading nontraumatic cause of neurologic disability in young adults. Interferon-beta, approved for use in 1993, was the first treatment to modify the course and prognosis of the disease and remains a mainstay of MS treatment. Numerous large-scale clinical trials in early, active patient populations have established the clinical efficacy of interferon-beta in reducing relapses and delaying disability progression. Although its mechanism of action remains incompletely understood, a reduction in active lesions seen on magnetic resonance imaging implies primary anti-inflammatory properties, a mechanism supported by basic immunologic research. Variation in individual patient responsiveness to interferon-beta may be due to disease variability or differential induction of interferon-stimulated genes. The magnitude of the therapeutic effect appears to be similar among products, but the optimal dose, route, and frequency of administration of the drug remain uncertain.

Detection of ectopic B-cell follicles with germinal centers in the meninges of patients with secondary progressive multiple sclerosis

Multiple sclerosis (MS) is characterized by synthesis of oligoclonal immunoglobulins and the presence of B-cell clonal expansions in the central nervous system (CNS). Because ectopic lymphoid tissue generated at sites of chronic inflammation is thought to be important in sustaining immunopathological processes, we have investigated whether structures resembling lymphoid follicles could be identified in the CNS of MS patients. Sections from post-mortem MS brains and spinal cords were screened using immunohistochemistry for the presence of CD20+ B-cells, CD3+ T-cells, CD138+ plasma cells and CD21+, CD35+ follicular dendritic cells, and for the expression of lymphoid chemokines (CXCL 13, CCL21) and peripheral node addressin (PNAd). Lymphoid follicle-like structures containing B-cells, T-cells and plasma cells, and a network of follicular dendritic cells producing CXCL13 were observed in the cerebral meninges of 2 out of 3 patients with secondary progressive MS, but not in relapsing remitting and primary progressive MS. We also show that proliferating B-cells are present in intrameningeal follicles, a finding which is suggestive of germinal center formation. No follicle-like structures were detected in parenchymal lesions. The formation of ectopic lymphoid follicies in the meninges of patients with MS could represent a critical step in maintaining humoral autoimmunity and in disease exacerbation.

Intracerebral expression of CXCL13 and BAFF is accompanied by formation of lymphoid follicle-like structures in the meninges of mice with relapsing experimental autoimmune encephalomyelitis

Given the abnormalities in B-cell activity occurring in the central nervous system (CNS) of patients with multiple sclerosis (MS), we have explored the possibility that CNS inflammation induced in mouse models of experimental autoimmune encephalomyelitis (EAE) triggers expression of molecules that control the development and functional organization of lymphoid follicles, the sites where B-cell responses are initiated. By reverse transcription-polymerase chain reaction (RT-PCR), we find that gene expression of CXCL13, a chemokine involved in B-cell recruitment into lymphoid follicles, and BAFF, a key regulator of B-cell survival, is markedly and persistently upregulated in the CNS of mice with relapsing-remitting and chronic-relapsing EAE. Using immunohistochemical techniques, we also show the presence of lymphoid follicle-like structures containing B cells and a reticulum of CXCL13+ and FDC-M1+ follicular dendritic cells within the meninges of several mice undergoing progressive relapsing EAE. These observations indicate that, under chronic inflammatory conditions, the less immunoprivileged meningeal compartment is the site where ectopic lymphoid follicles preferentially develop and where pathogenic B-cell responses could be sustained in autoimmune disorders of the CNS.

Intracerebral recruitment and maturation of dendritic cells in the onset and progression of experimental autoimmune encephalomyelitis

Dendritic cells (DCs) are thought to be key elements in the initiation and maintenance of autoimmune diseases. In this study, we sought evidence that DCs recruited to the central nervous system (CNS), a site that is primarily devoid of resident DCs, play a role in the effector phase and propagation of the immune response in experimental autoimmune encephalomyelitis (EAE). After immunization of SJL mice with proteolipid protein 139-151 peptide, process-bearing cells expressing the DC markers DEC-205 and CD11c appeared early in the spinal cord. During acute, chronic, and relapsing EAE, DEC-205(+) DCs expressing a lymphostimulatory phenotype (including the mature DC marker MIDC-8, major histocompatibility complex class II, CD40, and CD86 molecules) accumulated within the CNS inflammatory cell infiltrates. More prominent infiltration of the spinal cord parenchyma by mature DCs was observed in mice with relapsing disease. Macrophage inflammatory protein 3alpha, a chemokine active on DCs and lymphocytes, and its receptor CCR6 were up-regulated in the CNS during EAE. These findings suggest that intracerebral recruitment and maturation of DCs may be crucial in the local stimulation and maintenance of autoreactive immune responses, and that therapeutic strategies aimed at manipulating DC migration could be useful in the treatment of CNS autoimmune disorders.

Do self-perpetuating B lymphocytes drive human autoimmune disease?

Normal immunological memory is thought to be underpinned by T lymphocytes. However, in rheumatoid arthritis there are indications that T-lymphocyte control has been subverted by self-perpetuating B lymphocytes. Potential mechanisms in other autoimmune states are less clear, but a number of observations suggest that misappropriation of immunological memory by B lymphocytes may be a common feature of human autoantibody-associated disease. Put simply, autoantibodies drive their own production. If so, the availability of safe B-lymphocyte-depleting agents provides a potential means for reversal of autoimmunity.

Effect of treatment on oligoclonal IgG bands and intrathecal IgG synthesis in sequential cerebrospinal fluid and serum from patients with subacute sclerosing panencephalitis

Oligoclonal IgG bands were analyzed in matching pairs of cerebrospinal fluid (CSF) and serum from 12 subacute sclerosing panencephalitis (SSPE) patients, using isoelectric focusing and immunofixation. Each patient was given isoprinosine, and four of the 12 patients were given alpha-interferon in addition. Two to 4 serial CSF and serum samples were collected from each SSPE patient during periods ranging from 1 to 16 months. In 3 SSPE patients a small number of new oligoclonal bands were seen in the follow-up CSF samples. In the other 9 SSPE patients there was no change in CSF band patterns between initial and follow-up specimens. Band patterns in serum remained unchanged between initial and follow-up samples. Although all 12 SSPE cases had higher IgG indices and increased rate of intra blood-brain barrier (BBB) IgG synthesis in comparison to patients with other neurological diseases, the values did not significantly differ between the first and follow-up specimens. We conclude that treatment of SSPE patients with isoprinosine or with isoprinosine and alpha-interferon had no significant effect on the CSF oligoclonal band profiles or IgG synthesis within the central nervous system.

Immunointervention with cyclosporin A in autoimmune neurological disorders

Cyclosporin A has proven a remarkably effective compound in suppressing disease activity in a number of animal models of autoimmune neurological disorders. During the last decade a number of controlled clinical trials have been carried out in human neurological disorders which are considered to be immune-mediated. The results of those trials are reviewed.

Cerebrospinal fluid biochemistry in the diagnosis of multiple sclerosis

The Poser criteria for diagnosing multiple sclerosis (MS) includes clinical, paraclinical and laboratory information. We studied the influence of cerebrospinal fluid (CSF) biochemistry results on the categorisation of patients with suspected MS. A retrospective study was made of 138 patients who had CSF samples sent over a 1 year period to the laboratory for examination for oligoclonal bands. Using the Poser criteria, 23 patients were diagnosed as having definite MS and one patient as probable MS. Cerebrospinal fluid biochemistry upgraded the categorisation from probable to definite MS in 16 of these 24 patients (66%). In this study, we found oligoclonal bands to be more sensitive in the diagnosis of MS (96%) than either the concentration of IgG in the CSF (43.5%) or the IgG expressed as a percentage of the total protein in the CSF (71%). We conclude that CSF biochemistry is a valuable investigation in the evaluation of patients with suspected MS.

Intrathecal synthesis of immunoglobulin G in vascular dementia

Serum and CSF from 53 vascular dementia (VD) patients and 50 controls were analysed to investigate the possibility of an intrathecal synthesis of IgG, defined as an elevated IgG index (greater than or equal to 7) and/or presence of oligoclonal IgG in cerebrospinal fluid (CSF), but not in serum. Five (9%) patients and no controls exhibited an intrathecal synthesis of IgG. The IgG index increased with the degree of dementia (p less than 0.05). It was positively related to presence/absence of hypertension (p less than 0.05) and correlated positively with diastolic blood pressure (p less than 0.05). The findings suggest that immunological factors might be involved in the pathogenesis of VD.

Multiple sclerosis: relations between MRI and CT findings, cerebrospinal fluid parameters and clinical features

Cerebral MRI and CT findings were compared with various cerebrospinal fluid (CSF) parameters and clinical features in 75 patients with multiple sclerosis (MS). There were positive correlations between CSF albumin as a parameter of blood-brain barrier function and morphological parameters, namely the number of nonperiventricular foci and periventricular involvement demonstrated by MRI and ventricular enlargement as shown by CT. Apart from positive correlations between the number of nonperiventricular foci and CSF levels of IgA and IgG, including the IgG synthetic rate, no other correlations were found between CSF parameters (leucocyte count and immunoglobulin concentrations) and morphological findings. The unremitting-progressive type of MS was distinguished from the relapsing-remitting form by a lower CSF leucocyte count and a higher degree of disability, but there was no difference between the morphological findings in the two forms. Positive correlations were found between degree of disability and both periventricular involvement in the MRI and CT evidence of ventricular enlargement. In terms of correlations with the duration of disease, cerebral MRI proved to be far superior to CSF evaluations.

Multiple sclerosis intra-blood-brain-barrier IgG synthesis: effect of pulse intravenous and intrathecal corticosteroids

Nine severely disabled clinically definite chronic progressive multiple sclerosis (MS) patients who had at least one determination of intra-blood-brain-barrier (BBB) IgG synthesis rate of greater than 7 mg/day (upper limit of normal = 3.3) participated in this study. Seven patients were given 1 gram of methylprednisolone sodium succinate (MP) by intravenous infusion over 30 minutes once a day for 3 days. Statistically significant (p less than .05) reduction in intra-BBB IgG synthesis (mg/day) was seen in 4/7 patients, but in only 2 were normal levels of synthesis rate (less than 3.3 mg/day) attained. Rebound of IgG synthesis to premedication rates occurred within 30 days in 2/4 patients. There was no change in intensity or pattern of cerebrospinal fluid (CSF) oligoclonal IgG bands by isoelectric focusing, immunofixation, and silver staining. A subsequent course of intrathecal methylprednisolone acetate (MPA) (80 mg twice a week for 5 weeks) was given to 5 of the 7 patients and to 2 additional patients not previously treated. In spite of signs of subarachnoid inflammation, a statistically significant depression of intra-BB synthesis, which far exceeded that from the pulse treatment occurred in all 7, including the 2 patients whose intra-BBB IgG synthesis rates were previously resistant to pulse steroid administration. Normal levels of synthesis were rapidly reached in 4/7 patients; however, an IgG synthesis rebound occurred in 3/7 patients which was just as rapid. One out of 7 patients showed a temporary reduction in the number of cathodic IgG oligoclonal bands in the CSF. Two patients required discontinuation of treatment due to aseptic meningitis in one and progressive weakness in the other. Clinically, these severely afflicted patients with fixed deficits remained unchanged with either treatment protocol. While MPA and ACTH have similar initial effect on the central nervous systems (CNS) inflammatory response in MS, the well documented risk of serious adversities with MPA prohibit its clinical use in MS in its present form.

Multiple sclerosis: possible immunological mechanisms

Multiple sclerosis is the principal demyelinating disease of the central nervous system. Although the prevalence of the disease is moderately low, averaging about 40 cases per 100,000 people in high risk areas, it is a particularly devastating disease. It primarily affects young adults, is chronic, and has an unpredictable course. Most discouraging, the cause of the disease is not known and an effective treatment has not been identified. Recently, however, research has yielded some important findings concerning the etiology of MS. Much evidence now points to an immunological process as one of the major elements in the disease. It is also likely that an environmental influence, possibly an infectious process, may contribute to the disease. Finally, it is now certain that genetic makeup influences susceptibility to the disease. At present, the strongest evidence is for a polygenic effect, not the effect of a single gene or gene locus. This review will examine some of the possible immunologically mediated disease processes that could be involved in MS, especially those that could account for a role for infectious and genetic factors in the disease.

The long march of the cerebrospinal fluid profile indicative of clinical definite multiple sclerosis; and still marching

Much progress has been made, especially in the last two decades, in laboratory aids to diagnosis and to follow the course of patients with multiple sclerosis (MS). The cerebrospinal fluid (CSF) profile indicative of MS, though not pathognomonic of MS, is present in almost every case of clinical definite MS in a chronic progressive phase (probably also true for early MS). The cardinal aspect of the profile is intra-blood-brain barrier (BBB) IgG synthesis which can be qualitatively detected by determining unique CSF oligoclonal IgG bands and quantitated by rate formula, mg/day. We believe that intra-BBB IgG synthesis is caused by a persistent antigen, most likely a virus, possibly measles. A number of issues about the profile are proposed and opportunities are presented to resolve them.

Suppressor and cytolytic cell function in multiple sclerosis. Effects of cyclosporine A and interleukin 2

Patients with progressive multiple sclerosis (MS) demonstrated persistent reductions in levels of concanavalin A (Con A)-induced suppressor activity and heightened levels of in vitro pokeweed mitogen (PWM)-induced IgG secretion. The reduced Con A suppressor activity could not be reversed by addition of interleukin 2 (IL-2). Cyclosporine A (CsA) treatment did not alter the defect in Con A-induced suppressor activity, but did markedly inhibit T8+ cell-mediated alloantigen directed cytolytic activity; this latter defect was reversible by in vitro addition of IL-2. CsA-treated patients did not differ from placebo-treated patients with regard to levels of PWM-induced IgG secretion or proliferative responses of their mononuclear cells to Con A. The results indicate that CsA treatment of MS patients reduces cytolytic function from baseline normal values, but does not alter aberrant suppressor cell function.