Cerebrospinal fluid analysis differentiates between relapsing-remitting and secondary progressive multiple sclerosis

Free complement and complement containing extracellular vesicles as potential biomarkers for neuroinflammatory and neurodegenerative disorders

The complement system is implicated in a broad range of neuroinflammatory disorders such as Alzheimer's disease (AD) and multiple sclerosis (MS). Consequently, measuring complement levels in biofluids could serve as a potential biomarker for these diseases. Indeed, complement levels are shown to be altered in patients compared to controls, and some studies reported a correlation between the level of free complement in biofluids and disease progression, severity or the response to therapeutics. Overall, they are not (yet) suitable as a diagnostic tool due to heterogeneity of reported results. Moreover, measurement of free complement proteins has the disadvantage that information on their origin is lost, which might be of value in a multi-parameter approach for disease prediction and stratification. In light of this, extracellular vesicles (EVs) could provide a platform to improve the diagnostic power of complement proteins. EVs are nanosized double membrane particles that are secreted by essentially every cell type and resemble the (status of the) cell of origin. Interestingly, EVs can contain complement proteins, while the cellular origin can still be determined by the presence of EV surface markers. In this review, we summarize the current knowledge and future opportunities on the use of free and EV-associated complement proteins as biomarkers for neuroinflammatory and neurodegenerative disorders.

Cerebrospinal fluid findings in patients with myelin oligodendrocyte glycoprotein (MOG) antibodies. Part 1: Results from 163 lumbar punctures in 100 adult patients

BACKGROUND

New-generation cell-based assays have demonstrated a robust association of serum autoantibodies to full-length human myelin oligodendrocyte glycoprotein (MOG-IgG) with (mostly recurrent) optic neuritis, myelitis, and brainstem encephalitis, as well as with neuromyelitis optica (NMO)-like or acute-disseminated encephalomyelitis (ADEM)-like presentations. However, only limited data are yet available on cerebrospinal fluid (CSF) findings in MOG-IgG-associated encephalomyelitis (MOG-EM; also termed MOG antibody-associated disease, MOGAD).

OBJECTIVE

To describe systematically the CSF profile in MOG-EM.

MATERIAL AND METHODS

Cytological and biochemical findings (including white cell counts and differentiation; frequency and patterns of oligoclonal bands; IgG/IgM/IgA and albumin concentrations and CSF/serum ratios; intrathecal IgG/IgA/IgM fractions; locally produced IgG/IgM/IgA concentrations; immunoglobulin class patterns; IgG/IgA/IgM reibergrams; Link index; measles/rubella/zoster (MRZ) reaction; other anti-viral and anti-bacterial antibody indices; CSF total protein; CSF L-lactate) from 163 lumbar punctures in 100 adult patients of mainly Caucasian descent with MOG-EM were analyzed retrospectively.

RESULTS

Most strikingly, CSF-restricted oligoclonal IgG bands, a hallmark of multiple sclerosis (MS), were absent in almost 90% of samples (N = 151), and the MRZ reaction, the most specific laboratory marker of MS known so far, in 100% (N = 62). If present, intrathecal IgG (and, more rarely, IgM) synthesis was low, often transient and mostly restricted to acute attacks. CSF WCC was elevated in > 50% of samples (median 31 cells/μl; mostly lymphocytes and monocytes; > 100/μl in 12%). Neutrophils were present in > 40% of samples; activated lymphocytes were found less frequently and eosinophils and/or plasma cells only very rarely (< 4%). Blood-CSF barrier dysfunction (as indicated by an elevated albumin CSF/serum ratio) was present in 48% of all samples and at least once in 55% of all patients (N = 88) tested. The frequency and degree of CSF alterations were significantly higher in patients with acute myelitis than in patients with acute ON and varied strongly depending on attack severity. CSF L-lactate levels correlated significantly with the spinal cord lesion load in patients with acute myelitis (p < 0.0001). Like pleocytosis, blood-CSF barrier dysfunction was present also during remission in a substantial number of patients.

CONCLUSION

MOG-IgG-positive EM is characterized by CSF features that are distinct from those in MS. Our findings are important for the differential diagnosis of MS and MOG-EM and add to the understanding of the immunopathogenesis of this newly described autoimmune disease.

Cerebrospinal fluid findings in patients with myelin oligodendrocyte glycoprotein (MOG) antibodies. Part 2: Results from 108 lumbar punctures in 80 pediatric patients

BACKGROUND

New-generation, cell-based assays have demonstrated a robust association of serum autoantibodies to full-length human myelin oligodendrocyte glycoprotein (MOG-IgG) with (mostly recurrent) optic neuritis, myelitis, and brainstem encephalitis, as well as with neuromyelitis optica (NMO)-like or acute-disseminated encephalomyelitis (ADEM)-like presentations. However, only limited data are yet available on cerebrospinal fluid (CSF) findings in MOG-IgG-associated encephalomyelitis (MOG-EM; also termed MOG antibody-associated disease, MOGAD).

OBJECTIVE

To describe systematically the CSF profile in children with MOG-EM.

MATERIAL AND METHODS

Cytological and biochemical findings (including white cell counts [WCC] and differentiation; frequency and patterns of oligoclonal bands; IgG/IgM/IgA and albumin concentrations and CSF/serum ratios; intrathecal IgG/IgM/IgA fractions; locally produced IgG/IgM/IgA concentrations; immunoglobulin class patterns; IgG/IgA/IgM reibergrams; Link index; measles/rubella/zoster [MRZ] reaction; other anti-viral and anti-bacterial antibody indices; CSF total protein; CSF L-lactate) from 108 lumbar punctures in 80 pediatric patients of mainly Caucasian descent with MOG-EM were analyzed retrospectively.

RESULTS

Most strikingly, CSF-restricted oligoclonal IgG bands, a hallmark of multiple sclerosis (MS), were absent in 89% of samples (N = 96), and the MRZ reaction, the most specific laboratory marker of MS known so far, in 100% (N = 29). If present at all, intrathecal IgG synthesis was low, often transient and mostly restricted to acute attacks. Intrathecal IgM synthesis was present in 21% and exclusively detectable during acute attacks. CSF WCC were elevated in 54% of samples (median 40 cells/μl; range 6-256; mostly lymphocytes and monocytes; > 100/μl in 11%). Neutrophils were present in 71% of samples; eosinophils, activated lymphocytes, and plasma cells were seen only rarely (all < 7%). Blood-CSF barrier dysfunction (as indicated by an elevated albumin CSF/serum ratio) was present in 46% of all samples (N = 79) and at least once in 48% of all patients (N = 67) tested. CSF alterations were significantly more frequent and/or more pronounced in patients with acute spinal cord or brain disease than in patients with acute ON and varied strongly depending on attack severity. CSF L-lactate levels correlated significantly with the spinal cord lesions load (measured in vertebral segments) in patients with acute myelitis (p = 0.0099). An analysis of pooled data from the pediatric and the adult cohort showed a significant relationship of QAlb (p < 0.0005), CST TP (p < 0.0001), and CSF L-lactate (p < 0.0003) during acute attacks with age.

CONCLUSION

MOG-IgG-associated EM in children is characterized by CSF features that are distinct from those in MS. With regard to most parameters, no marked differences between the pediatric cohort and the adult cohort analyzed in Part 1 were noted. Our findings are important for the differential diagnosis of pediatric MS and MOG-EM and add to the understanding of the immunopathogenesis of this newly described autoimmune disease.

Chicken-or-egg question: Which came first, extracellular vesicles or autoimmune diseases?

Extracellular vesicles (EVs) have attracted great interest as contributors to autoimmune disease (AD) pathogenesis, owing to their immunomodulatory potential; they may also play a role in triggering tolerance disruption, by delivering auto‐antigens. EVs are released by almost all cell types, and afford paracrine or distal cell communication, functioning as biological carriers of active molecules including lipids, proteins, and nucleic acids. Depending on stimuli from the external microenvironment or on their cargo, EVs can promote or suppress immune responses. ADs are triggered by inappropriate immune‐system activation against the self, but their precise etiology is still poorly understood. Accumulating evidence indicates that lifestyle and diet have a strong impact on their clinical onset and development. However, to date the mechanisms underlying AD pathogenesis are not fully clarified, and reliable markers, which would provide early prediction and disease progression monitoring, are lacking. In this connection, EVs have recently been indicated as a promising source of AD biomarkers. Although EV isolation is currently based on differential centrifugation or density‐gradient ultracentrifugation, the resulting co‐isolation of contaminants (i.e., protein aggregates), and the pooling of all EVs in one sample, limit this approach to abundantly‐expressed EVs. Flow cytometry is one of the most promising methods for detecting EVs as biomarkers, and may have diagnostic applications. Furthermore, very recent findings describe a new method for identifying and sorting EVs by flow cytometry from freshly collected body fluids, based on specific EV surface markers.

A minimal unified model of disease trajectories captures hallmarks of multiple sclerosis

Multiple Sclerosis (MS) is an autoimmune disease targeting the central nervous system (CNS) causing demyelination and neurodegeneration leading to accumulation of neurological disability. Here we present a minimal, computational model involving the immune system and CNS that generates the principal subtypes of the disease observed in patients. The model captures several key features of MS, especially those that distinguish the chronic progressive phase from that of the relapse-remitting. In addition, a rare subtype of the disease, progressive relapsing MS naturally emerges from the model. The model posits the existence of two key thresholds, one in the immune system and the other in the CNS, that separate dynamically distinct behavior of the model. Exploring the two-dimensional space of these thresholds, we obtain multiple phases of disease evolution and these shows greater variation than the clinical classification of MS, thus capturing the heterogeneity that is manifested in patients.

Cerebrospinal fluid findings in aquaporin-4 antibody positive neuromyelitis optica: results from 211 lumbar punctures

BACKGROUND

Neuromyelitis optica (NMO, Devic disease) is a severely disabling autoimmune disorder of the CNS, which was considered a subtype of multiple sclerosis (MS) for many decades. Recently, however, highly specific serum autoantibodies (termed NMO-IgG or AQP4-Ab) have been discovered in a subset (60-80%) of patients with NMO. These antibodies were subsequently shown to be directly involved in the pathogenesis of the condition. AQP4-Ab positive NMO is now considered an immunopathogenetically distinct disease in its own right. However, to date little is known about the cerebrospinal fluid (CSF) in AQP4-Ab positive NMO.

OBJECTIVE

To describe systematically the CSF profile of AQP4-Ab positive patients with NMO or its formes frustes, longitudinally extensive myelitis and optic neuritis.

MATERIAL AND METHODS

Cytological and protein biochemical results from 211 lumbar punctures in 89 AQP4-Ab positive patients of mostly Caucasian origin with neuromyelitis optica spectrum disorders (NMOSD) were analysed retrospectively.

RESULTS

CSF-restricted oligoclonal IgG bands, a hallmark of MS, were absent in most patients. If present, intrathecal IgG (and, more rarely, IgM) synthesis was low, transient, and, importantly, restricted to acute relapses. CSF pleocytosis was present in around 50% of samples, was mainly mild (median, 19 cells/μl; range 6-380), and frequently included neutrophils, eosinophils, activated lymphocytes, and/or plasma cells. Albumin CSF/serum ratios, total protein and CSF L-lactate levels correlated significantly with disease activity as well as with the length of the spinal cord lesions in patients with acute myelitis. CSF findings differed significantly between patients with acute myelitis and patients with acute optic neuritis at the time of LP. Pleocytosis and blood CSF barrier dysfunction were also present during remission in some patients, possibly indicating sustained subclinical disease activity.

CONCLUSION

AQP4-Ab positive NMOSD is characterized by CSF features that are distinct from those in MS. Our findings are important for the differential diagnosis of MS and NMOSD and add to our understanding of the immunopathogenesis of this devastating condition.

Cerebrospinal fluid and blood biomarkers of neuroaxonal damage in multiple sclerosis

Following emerging evidence that neurodegenerative processes in multiple sclerosis (MS) are present from its early stages, an intensive scientific interest has been directed to biomarkers of neuro-axonal damage in body fluids of MS patients. Recent research has introduced new candidate biomarkers but also elucidated pathogenetic and clinical relevance of the well-known ones. This paper reviews the existing data on blood and cerebrospinal fluid biomarkers of neuroaxonal damage in MS and highlights their relation to clinical parameters, as well as their potential predictive value to estimate future disease course, disability, and treatment response. Strategies for future research in this field are suggested.

Cerebrospinal fluid evidence of increased extra-mitochondrial glucose metabolism implicates mitochondrial dysfunction in multiple sclerosis disease progression

In contrast to relapse, the mechanisms of multiple sclerosis (MS) disease progression are less understood and appear not to be exclusively inflammatory in nature. In this pilot study we investigated the relationship between disturbed CNS energy metabolism and MS disease progression. We tested the hypothesis that cerebrospinal fluid (CSF) concentrations of sorbitol, fructose, and lactate, all metabolites of extra-mitochondrial glucose metabolism, would be elevated in secondary progressive (SP) MS patients and would be associated with worsening neurologic disability. We measured metabolite concentrations by gas chromatographic/mass spectrometric and enzymatic methods in archived CSF samples from 85 MS patients [31 relapsing-remitting (RR) and 54 SP patients] and 18 healthy controls. We found that concentrations of all three metabolites, but not concentrations of glucose or myoinositol, were significantly increased in CSF from SP and, to a lesser degree, RR patients, compared to controls. Furthermore, CSF concentrations of sorbitol and fructose (polyol pathway metabolites), but not lactate (anaerobic glycolysis metabolite), correlated positively and significantly with Expanded Disability Status Scale (EDSS) score, an index of neurologic disability in MS patients. We conclude that extra-mitochondrial glucose metabolism is increased in MS patients and is associated with disease progression evidenced by increasing EDSS score. As extra-mitochondrial glucose metabolism increases with impaired mitochondrial metabolism of glucose, these findings implicate mitochondrial dysfunction in the pathogenesis of MS disease progression. CSF metabolic profiling may be useful in clarifying the role of mitochondrial pathology in progression and in targeting and monitoring therapies for disease progression that aim to preserve or boost mitochondrial glucose metabolism.

Cerebrospinal fluid S-100 protein levels in neurological pathologies

The aim of this paper was to evaluate S-100 concentration in cerebrospinal fluid (CSF) from patients with different neurological disorders, and in subjects with no proven neurological pathology, in order to study possible differences in their protein concentrations. The total number of patient-samples examined was 119 (58 males and 61 females; mean age 35 yrs, 1-79 yrs). Based on the final diagnoses, nine patient groups were studied: a control group, meningitis, acute lymphatic leukemia (ALL), dementia, hydrocephalia, polyneuropathy-motor neuron disease, acute cerebral infarction (ACI), and patients diagnosed with multiple sclerosis. S-100 protein concentrations were measured by the Sangtec 100 two-site immunoradiometric assay. The highest S-100 levels in CSF were found in the dementia group, ACI group, bacterial-fungal and lymphocytic meningitis groups (Kruskal-Wallis test). The S-100 concentrations in these groups were significantly higher compared with the control group (Mann-Whitney U test, p<0.05, p<0.01) and the multiple sclerosis group (p<0.05, p<0.01). No other significant differences were found between groups. Our results suggest that the high protein levels in CSF found in these pathologies may reflect the presence of brain damage. However, the levels need to be considered individually, as they depend on several factors, such as age, severity of brain damage or interval between the onset of brain damage and the taking of the sample.

Detection of the 14-3-3 protein in the cerebrospinal fluid of Japanese multiple sclerosis patients presenting with severe myelitis

Recent studies showed that the 14-3-3 protein is detectable in the cerebrospinal fluid (CSF) of prion-unrelated neurological diseases, such as meningoencephalitis and myelitis. To investigate the possible association between the amounts of the 14-3-3 protein in the CSF and the clinical severity of multiple sclerosis (MS), its levels were determined by Western blot in the CSF of the patients with relapsing-remitting MS (RRMS) (n=10), secondary progressive MS (SPMS) (n=7), primary progressive MS (PPMS) (n=2), and non-MS inflammatory diseases of the CNS (n=5). The 14-3-3 protein was identified in seven CSF samples, including four patients with SPMS in acute relapse, one with SPMS in remission accompanied by fresh cerebral infarction, one with RRMS in acute relapse, and one with human T-lymphotropic virus type I (HTLV-I)-associated myelopathy. The patients positive for the CSF 14-3-3 protein immunoreactivity showed more severe disability and higher levels of pleocytosis, protein, IgG, beta2-microglobulin, and neuron-specific enolase in the CSF, compared with those negative for its immunoreactivity. Four of these patients exhibited extensive lesions distributed along multiple vertebral segments in the spinal cord on MRI. In contrast, none of the MS patients without an extensive involvement of the spinal cord showed the CSF 14-3-3 protein immunoreactivity. These results suggest that detection of the 14-3-3 protein in the CSF provides a marker for severe inflammation-induced extensive damage of the central nervous system tissues responsible for poor therapeutic responses and irreversible neurological deficits in MS.

Serum S100beta: a noninvasive marker of blood-brain barrier function and brain lesions

BACKGROUND

S100beta protein is expressed constitutively by brain astrocytes. Elevated S100beta levels in cerebrospinal fluid and serum reported after head trauma, subarachnoid hemorrhage, and stroke were correlated with the extent of brain damage. Because elevated serum S100beta also was shown to indicate blood-brain barrier (BBB) dysfunction in the absence of apparent brain injury, it remains unclear whether elevation of serum levels of S100beta reflect BBB dysfunction, parenchymal damage, or both.

METHODS

The authors conducted a prospective study of serum S100beta levels in six patients who underwent hyperosmotic BBB disruption (BBBD) with intraarterial chemotherapy for primary central nervous system lymphoma. In addition, 53 serum S100beta samples were measured in 51 patients who had a variety of primary or metastatic brain lesions at the time of neuroimaging.

RESULTS

S100beta was correlated directly with the degree of clinical and radiologic signs of BBBD in patients who were enrolled in the hyperosmotic study. In patients with neoplastic brain lesions, gadolinium enhancement on a magnetic resonance image was correlated with elevated S100beta levels (n = 45 patients; 0.16 +/- 0.1 microg/L; mean +/- standard error of the mean) versus nonenhancing scans (n = 8 patients; 0.069 +/- 0.04 microg/L). Primary brain tumors (n = 8 patients; 0.12 +/- 0.08) or central nervous system metastases also presented with elevated serum S100beta levels (n = 27 patients; 0.14 +/- 0.34). Tumor volume was correlated with serum S100beta levels only in patients with vestibular schwannoma (n = 6 patients; 0.13 +/- 0.10 microg/L) but not in patients with other brain lesions.

CONCLUSIONS

S100beta was correlated directly with the extent and temporal sequence of hyperosmotic BBBD, further suggesting that S100beta is a marker of BBB function. Elevated S100beta levels may indicate the presence of radiologically detectable BBB leakage. Larger prospective studies may better determine the true specificity of S100beta as a marker for BBB function and as an early detection or follow-up marker of brain tumors.

[Multiple sclerosis: clinical and laboratorial correlation]

The clinical and demographic characteristics of 86 Brazilian patients with clinically definite multiple sclerosis (MS) were compared to the cerebrospinal fluid (CSF) findings. The disease course was relapsing-remitting in 71% and chronic progressive in 29% of the cases. The IgG index was increased in 76% in the chronic progressive status and 46% and 49% during the bout and remission, respectively (p < 0.005). Only 36% of the MS patients using corticosteroids had increased IgG index, in comparison to the 64% of the patients without immunosupressive treatment. Oligoclonal IgG bands were detected in the CSF of 77% and 88% of the MS corticosteroids users and non-users, respectively. The quantitative study of intrathecal synthesis of IgG contributes to demonstrate the immunological differences between the two forms of MS, the relapsing-remitting and the chronic progressive. The treatment with corticosteroids decreases quantitatively the intrathecal synthesis of IgG but not the presence of oligoclonal bands.

Biological markers in body fluids for activity and progression in multiple sclerosis

Reliable biological markers in body fluids for disease activity and progression are important for our understanding of the pathophysiology and therapeutic decisions in various subtypes of multiple sclerosis. Sampling from body fluids such as cerebrospinal fluid, blood, and urine constitutes the problem that the local immuno-inflammatory process takes place in the central nervous system whereas the disease activity is only to some extent reflected in the systemic immune compartment. Promising results have been obtained in studies of adhesion molecules, pro-inflammatory cytokines, co-stimulatory molecules and neopterin as markers of disease activity in relapsing-remitting multiple sclerosis. However, these results apply to groups of patients but not necessarily to individual patients. Currently no single body fluid marker is sufficiently correlated to disease activity to be used in the individual patient in monitoring disease activity, progression, or therapeutic effects.

Composite cerebrospinal fluid score in relapsing-remitting and secondary progressive multiple sclerosis

We investigated whether cerebrospinal fluid (CSF) analysis may differentiate between relapsing-remitting (RR) and secondary progressive (SP) multiple sclerosis (MS). In 17 RR and 16 SP patients we determined: albumine CSF/PB ratio; mononuclear cell (MNC) number, CD4+, CD8+, and B1+ subsets, CD4+/CD8+ ratio; IgG, IgG index, IgM, IgM index, complement components C3 and C4, and C3 and C4 indexes; myelin basic protein; neuron-specific enolase (NSE); S100; and lactate. For each parameter the statistical distance was calculated. Then, using linear discriminant analysis, we computed a discriminant score, including only variables with a P value less than or equal to 0.15: albumin CSF/PB ratio, MNC number, IgM, IgM index, C3, C4, NSE, S100, and lactate. The discriminant score allocated all 17 RR patients to the RR group and 15 of 16 SP patients to the SP group. We conclude that RR and SP MS patients differ with respect to CSF profile and that in individual patients a composite CSF score may differentiate between RR and SP MS.

Body fluid markers to monitor multiple sclerosis: the assays and the challenges

The need for reliable markers of disease activity in multiple sclerosis (MS) to better guide basic research, diagnosis, treatment, and monitoring of therapy is well-recognized. A recent European Charcot Foundation Symposium (Body fluid markers for course and activity of disease in multiple sclerosis (Madrid, Spain, October 2-4, 1997) organized by the European Charcot Foundation and the Fundación Española de Esclerosis Múltiple (the Spanish Multiple Sclerosis Foundation) brought together experts in the field to review the state of the art for the technology measuring markers in body fluids. An array of different approaches was presented to measure a wide diversity of classic and novel marker molecules, including cytokines, adhesion molecules, myelin compounds, and free antibody light chains, in either blood, urine, or cerebrospinal fluid. Here, recent progress in these approaches is assessed in the context of distinct pathophysiological stages of the disease, the requirements which such molecules and assays should ideally meet, and the practical and conceptual challenges which they face. Recommendations for further improvements are described.