Interleukin-6 levels in the cerebrospinal fluid and serum of patients with Guillain-Barré syndrome and chronic inflammatory demyelinating polyradiculoneuropathy

Cytokines and chemokines in patients with chronic inflammatory demyelinating polyradiculoneuropathy and multifocal motor neuropathy: A systematic review

Advances in the understanding of cytokines have revolutionized mechanistic treatments for chronic inflammatory and autoimmune diseases, as exemplified by rheumatoid arthritis. We conducted a systematic literature review on the role of cytokines and chemokines in chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) and multifocal motor neuropathy (MMN). Ovid Medline, EMBASE and Web of Science were searched until August 31, 2022 for human studies investigating cytokines levels in CIDP or MMN. Fifty-five articles on 1061 CIDP patients and 86 MMN patients were included, with a median of 18 patients per study (range 3-71). Studies differed in the inclusion criteria, type of assay, manufacturer, control subjects, and tested biological material. Only a minority of studies reported data on disease activity. Interleukin (IL)-6, IL-17, CXCL10, and tumor necrosis factor alpha (TNF-α), were elevated in CIDP compared to controls in most of the studies. IL-6 and TNF-α levels are also correlated with disability. In MMN patients, IL-1Ra was elevated in the majority of the reports. While acknowledging the challenges in comparing studies and the various limitations of the studies, including small patient numbers, particularly in MMN, our review suggests that IL-6, IL-17, CXCL10, and TNF-α might play a role in CIDP pathogenesis. Larger studies are needed in MMN.

COVID-19-associated serum and cerebrospinal fluid cytokines in post- versus para-infectious SARS-CoV-2-related Guillain-Barré syndrome

INTRODUCTION

Guillain-Barré syndrome associated with Coronavirus-2-related severe acute respiratory syndrome (COV-GBS) occurs as para- or post-infectious forms, depending on the timing of disease onset. In these two forms, we aimed to compare the cerebrospinal fluid (CSF) and serum proinflammatory cytokine profiles to evaluate differences that could possibly have co-pathogenic relevance.

MATERIALS AND METHODS

We studied a retrospective cohort of 26 patients with either post-COV-GBS (n = 15), with disease onset occurring > 7 days after SARS-CoV-2 infection, or para-COV-GBS (n = 11), with disease onset 7 days or less. TNF-α, IL-6, and IL-8 were measured in the serum with SimplePlex™ Ella™ immunoassay. In addition to the para-/post-COV-GBS patients, serum levels of these cytokines were determined in those with non-COVID-associated-GBS (NC-GBS; n = 43), paucisymptomatic SARS-CoV-2 infection without GBS (COVID, n = 20), and in healthy volunteers (HV; n = 12). CSF cytokine levels were measured in patients with para-/post-COV-GBS, in those with NC-GBS (n = 29), or with Alzheimer's disease (AD; n = 24).

RESULTS

Serum/CSF cytokine levels did not differ in para- vs post-COV-GBS. We found that SARS-CoV-2 infection raises the serum levels of TNF-α, IL-6, and IL-8, as well as an increase of IL-6 (in serum and CSF) and IL-8 (in CSF) in either NC-GBS or COV-GBS than controls. CSF and serum cytokine levels resulted independent one with another.

CONCLUSIONS

The change of cytokines linked to SARS-CoV-2 in COV-GBS appears to be driven by viral infection, although it has unique characteristics in GBS as such and does not account for cases with para- or post-infectious onset.

Disease activity in chronic inflammatory demyelinating polyneuropathy: association between circulating B-cell subsets, cytokine levels, and clinical outcomes

Chronic inflammatory demyelinating polyneuropathy (CIDP), a common and treatable autoimmune neuropathy, is frequently misdiagnosed. The aim of this study is to evaluate the relationship between immunological markers and clinical outcome measures in a mixed cohort of patients with typical CIDP and CIDP variants at different disease stages. Twenty-three typical, 16 multifocal and five distal CIDP patients were included. Twenty-five sex and age-matched healthy controls and 12 patients with Charcot-Marie-Tooth type 1A (CMT1A) disease served as controls. Peripheral B-cell populations were analyzed by flow cytometry. IL6, IL10, TNFA mRNA and mir-21, mir-146a, and mir-155-5p expression levels were evaluated by real-time polymerase chain reaction in peripheral blood mononuclear cells (PBMC) and/or skin biopsy specimens. Results were then assessed for a possible association with clinical disability scores and intraepidermal nerve fiber densities (IENFD) in the distal leg. We detected a significant reduction in naive B cells (P ≤ 0.001), plasma cells (P ≤ 0.001) and regulatory B cells (P < 0.05), and an elevation in switched memory B cells (P ≤ 0.001) in CIDP compared to healthy controls. CMT1A and CIDP patients had comparable B-cell subset distribution. CIDP cases had significantly higher TNFA and IL10 gene expression levels in PBMC compared to healthy controls (P < 0.05 and P ≤ 0.01, respectively). IENFDs in the distal leg showed a moderate negative correlation with switched memory B-cell ratios (r = -0.51, P < 0.05) and a moderate positive correlation with plasma cell ratios (r = 0.46, P < 0.05). INCAT sum scores showed a moderate positive correlation with IL6 gene expression levels in PBMC (r = 0.54, P < 0.05). Altered B-cell homeostasis and IL10 and TNFA gene expression levels imply chronic antigen exposure and overactivity in the humoral immune system, and seem to be a common pathological pathway in both typical CIDP and CIDP variants.

Characteristic cerebrospinal fluid findings in immune checkpoint inhibitor-related peripheral neuropathy: A case report

Although immune checkpoint inhibitors (ICIs) are widely used to treat unresectable malignant tumors, they can cause undesirable side effects called immune-related adverse events, including neurological toxicities. Here, we describe a case of ICI-related peripheral neuropathy (irPN) with characteristic cerebrospinal fluid (CSF) findings. In addition to pleocytosis and increased protein levels, the present case showed increased levels of CSF soluble interleukin-2 receptor (sIL-2R), IL-6, and IL-10, suggesting activated T cell-related autoimmunity. We believe that CSF cytokines and sIL-2R could be novel biomarkers of irPN.

Repurposing MS immunotherapies for CIDP and other autoimmune neuropathies: unfulfilled promise or efficient strategy?

Despite advances in the treatment of chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) and other common autoimmune neuropathies (AN), still-many patients with these diseases do not respond satisfactorily to the available treatments. Repurposing of disease-modifying therapies (DMTs) from other autoimmune conditions, particularly multiple sclerosis (MS) and neuromyelitis optica spectrum disorders (NMOSD), is a promising strategy that may accelerate the establishment of novel treatment choices for AN. This approach appears attractive due to homologies in the pathogenesis of these diseases and the extensive post-marketing experience that has been gathered from treating MS and NMOSD patients. The idea is also strengthened by a number of studies that explored the efficacy of DMTs in animal models of AN but also in some CIDP patients. We here review the available preclinical and clinical data of approved MS therapeutics in terms of their applicability to AN, especially CIDP. Promising therapeutic approaches appear to be B cell-directed and complement-targeting strategies, such as anti-CD20/anti-CD19 agents, Bruton's tyrosine kinase inhibitors and anti-C5 agents, as they exert their effects in the periphery. This is a major advantage because, in contrast to MS, their action in the periphery is sufficient to exert significant immunomodulation.

Systemic inflammatory markers in patients with polyneuropathies

Introduction

In patients with peripheral neuropathies (PNP), neuropathic pain is present in 50% of the cases, independent of the etiology. The pathophysiology of pain is poorly understood, and inflammatory processes have been found to be involved in neuro-degeneration, -regeneration and pain. While previous studies have found a local upregulation of inflammatory mediators in patients with PNP, there is a high variability described in the cytokines present systemically in sera and cerebrospinal fluid (CSF). We hypothesized that the development of PNP and neuropathic pain is associated with enhanced systemic inflammation.

Methods

To test our hypothesis, we performed a comprehensive analysis of the protein, lipid and gene expression of different pro- and anti-inflammatory markers in blood and CSF from patients with PNP and controls.

Results

While we found differences between PNP and controls in specific cytokines or lipids, such as CCL2 or oleoylcarnitine, PNP patients and controls did not present major differences in systemic inflammatory markers in general. IL-10 and CCL2 levels were related to measures of axonal damage and neuropathic pain. Lastly, we describe a strong interaction between inflammation and neurodegeneration at the nerve roots in a specific subgroup of PNP patients with blood-CSF barrier dysfunction.

Conclusion

In patients with PNP systemic inflammatory, markers in blood or CSF do not differ from controls in general, but specific cytokines or lipids do. Our findings further highlight the importance of CSF analysis in patients with peripheral neuropathies.

COVID-19 and Guillain-Barré syndrome: A single-center prospective case series with a 1-year follow-up

Single reports of Guillain-Barré syndrome (GBS) have been reported worldwide during the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic. While case reports are likely to be biased toward uncommon clinical presentations, systematic assessment of prospective series can highlight the true clinical features and spectrum. In this prospective, observational study, we included all consecutive patients who developed GBS. In patients with SARS-CoV-2 infection as antecedent, the time-gap between the infection and GBS onset had to be ≤30 days. The referral was a neurological University Research Hospital, in the Italian Region more severely involved by the pandemic, and hospitalizing both COVID+ and non-COVID neurological diseases. Clinical, laboratory, cerebrospinal fluid, and electromyographic features of GBS diagnosed between March 2020 and March 2021 were compared to a retrospective series of GBS diagnosed between February 2019 and February 2020 (control population). Nasopharyngeal swab was still positive at GBS onset in 50% of patients. Mild-to-moderate COVID-related pneumonia, as assessed by X-ray (6 patients) or X-ray plus computerized tomography (2 patients) co-occurred in 6 of 10 patients. GBS diagnosed during the pandemic period, including 10 COVID-GBS and 10 non-COVID-GBS, had higher disability on admission (P = .032) compared to the GBS diagnosed between February 2019 and 2020, possibly related to later hospital referral in the pandemic context. Compared to non-COVID-GBS (n = 10) prospectively diagnosed in the same period (March 2020-2021), post-COVID-GBS (n = 10) had a higher disability score on admission (P = .028), lower sum Medical Research Council score (P = .022) and lymphopenia (P = .025), while there were no differences in GBS subtype/variant, severity of peripheral involvement, prognosis and response to treatment. Cerebrospinal fluid search for SARS-CoV-2 RNA and antiganglioside antibodies were negative in all COVID+ patients. Temporal clustering of cases, coinciding with the waves of the pandemic, and concomitant reduction of the incidence of COVID-negative GBSs may indicate a role for SARS-CoV-2 infection in the development of GBS, although the association may simply be related to a bystander effect of systemic inflammation; lack of prevalence of specific GBS subtypes in post-COVID-GBS also support this view. GBS features and prognosis are not substantially different compared to non-COVID-GBS.

The Role of the Complement System in Chronic Inflammatory Demyelinating Polyneuropathy: Implications for Complement-Targeted Therapies

Chronic inflammatory demyelinating polyneuropathy (CIDP) is the most common, heterogeneous, immune-mediated neuropathy, characterized by predominant demyelination of motor and sensory nerves. CIDP follows a relapsing-remitting or a progressive course and causes substantial disability. The pathogenesis of CIDP involves a complex interplay of multiple aberrant immune responses, creating a pro-inflammatory environment, subsequently inflicting damage on the myelin sheath. Though the exact triggers are unclear, diverse immune mechanisms encompassing cellular and humoral pathways are implicated. The complement system appears to play a role in promoting macrophage-mediated demyelination. Complement deposition in sural nerve biopsies, as well as signs of increased complement activation in serum and CSF of patients with CIDP, suggest complement involvement in CIDP pathogenesis. Here, we present a comprehensive overview of the preclinical and clinical evidence supporting the potential role of the complement system in CIDP. This understanding furnishes a strong rationale for targeting the complement system to develop new therapies that could serve the unmet needs of patients affected by CIDP, particularly in those refractory to standard therapies.

Impact of Neurofascin on Chronic Inflammatory Demyelinating Polyneuropathy via Changing the Node of Ranvier Function: A Review

The effective conduction of action potential in the peripheral nervous system depends on the structural and functional integrity of the node of Ranvier and paranode. Neurofascin (NF) plays an important role in the conduction of action potential in a saltatory manner. Two subtypes of NF, NF186, and NF155, are involved in the structure of the node of Ranvier. In patients with chronic inflammatory demyelinating polyneuropathy (CIDP), anti-NF antibodies are produced when immunomodulatory dysfunction occurs, which interferes with the conduction of action potential and is considered the main pathogenic factor of CIDP. In this study, we describe the assembling mechanism and anatomical structure of the node of Ranvier and the necessary cell adhesion molecules for its physiological function. The main points of this study are that we summarized the recent studies on the role of anti-NF antibodies in the changes in the node of Ranvier function and its impact on clinical manifestations and analyzed the possible mechanisms underlying the pathogenesis of CIDP.

Expression analysis of cytokine transcripts in inflammatory demyelinating polyradiculoneuropathy

Inflammatory demyelinating polyradiculoneuropathies are a group of peripheral nerve system disorders in which immune reactions are dysregulated. Cytokines have noticeable roles in the regulation of these responses. We compared transcript levels of nine cytokine coding genes namely IL-1B, IL-2, IL-4, IL-6, IL-8, IL-17A, IFN-G, TGF-B and TNF-A in the peripheral blood of patients with acute and chronic kinds of this condition (AIDP and CIDP) and healthy persons. Expression of IL-17A was significantly lower in female AIDP cases compared with female controls (Expression Ratio = 0.02, P value = 0.02). Expression of this cytokine was higher in female CIDP cases compared with female AIDP cases (Expression ratio = 65.69, P value = 0.02). Moreover, expression of IL-6 tended to be diminished in female AIDP cases compared with normal females (Expression Ratio = 0.06, P value = 0.05). Expression of TGF-B was lower in female AIDP cases compared with female controls (Expression Ratio = 0.06, P value = 0.01). Transcript amounts of IL-1B were lower in whole CIDP cases compared with whole controls and in female AIDP cases compared with female controls (Expression Ratios = 0.09 and 0.00; P values = 0.04 and 0.01, respectively). Expression of this gene was considerably increased in female CIDP cases compared with female AIDP cases (Expression Ratio = 764.10, P value = 0.02). Finally, expression of this gene was lower in total cases compared with total controls (Expression ratio = 0.19, P value = 0.03). Diagnostic power of IL-4 was estimated to be 0.7 in differentiating between CIDP cases and controls. IL-1B had the diagnostic power of 0.72 in distinguishing between ADP cases and controls. Finally, TNF-A had the diagnostic power of 0.71 in differentiating between AIDP cases and CIDP cases. The current results suggest the possible role of these cytokines in the pathogenesis of inflammatory demyelinating polyradiculoneuropathies.

The immune response and aging in chronic inflammatory demyelinating polyradiculoneuropathy

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) consists of various autoimmune subtypes in which the peripheral nervous system (PNS) is attacked. CIDP can follow a relapsing-remitting or progressive course where the resultant demyelination caused by immune cells (e.g., T cells, macrophages) and antibodies can lead to disability in patients. Importantly, the age of CIDP patients has a role in their symptomology and specific variants have been associated with differing ages of onset. Furthermore, older patients have a decreased frequency of functional recovery after CIDP insult. This may be related to perturbations in immune cell populations that could exacerbate the disease with increasing age. In the present review, the immune profile of typical CIDP will be discussed followed by inferences into the potential role of relevant aging immune cell populations. Atypical variants will also be briefly reviewed followed by an examination of the available studies on the immunology underlying them.

Papilledema in Chronic Inflammatory Demyelinating Polyradiculoneuropathy (CIDP): A Pediatric Case and Review of the Literature

OBJECTIVE

To analyze the available literature on papilledema in chronic inflammatory demyelinating polyradiculoneuropathy (CIDP), report the first detailed pediatric case, and explore the underlying pathophysiology.

METHODS

First, we conducted a comprehensive literature review of all cases of papilledema in CIDP. Next, we reviewed each case, incorporating only those including cerebrospinal fluid analysis into the results. Finally, we present our pediatric patient.

RESULTS

Our literature review yielded a total of 9 adult and no pediatric cases. Cerebrospinal fluid protein and opening pressures were elevated in all cases. They were also elevated in our pediatric case.

CONCLUSION

Prolonged periods of active immune-mediated inflammation is likely a cause of papilledema in adult CIDP, and possibly also in our pediatric case.

Evidence of altered Th17 pathway signatures in the cerebrospinal fluid of patients with Guillain Barré Syndrome

Data indexing the contribution of various immuno-inflammatory components in the cerebrospinal fluid (CSF) towards the pathophysiology of Guillain Barré Syndrome (GBS) are limited. Th17 pathway plays crucial role in many immune mediated disorders of the nervous system. This study was aimed at exploring the role of Th17 pathway related cytokines in the CSF of patients with GBS. Levels of multiple key cytokines of Th17 pathway in CSF of patients with GBS (N = 37) and controls (N = 37) were examined in this prospective study using Bio-plex Pro Human Th17 cytokine assays in a Multiplex Suspension Array platform. The findings were correlated with clinical features and electrophysiological subtypes. Three key cytokines of Th17 pathway (IL-6, IL-17A and IL-22) were significantly elevated in CSF of patients with GBS as compared to controls. There was a positive correlation between the levels of IL-6 and IL-17A as well as between the levels of IL-17A and IL-22 in the CSF of patients with GBS. The CSF levels of IL-6 and IL-22 were negatively correlated with the duration of symptoms of GBS. None of the studied cytokines correlated with functional disability scores at admission to hospital or with the electrophysiological subtypes. Identification of Th17 pathway signatures in CSF sheds more insights into the pathogenic role of Th17 cells in GBS. These findings complement the contemporary knowledge and tender further support towards the involvement of Th17 pathway in GBS.

Serum levels of inflammatory cytokines in patients with idiopathic carpal tunnel syndrome

Objectives: Carpal tunnel syndrome (CTS) is a disorder caused by median nerve pressure inside the carpal tunnel in the wrist area. Recent evidences have demonstrated a role of cytokines in CTS. It is still controversial whether idiopathic CTS is an inflammatory or non-inflammatory disorder. Accordingly, the purpose of the current research was to assess serum levels of inflammatory cytokines in patients with idiopathic carpal tunnel syndrome in comparison with healthy participants.Methods: This case-control research was performed on 40 female patients with idiopathic carpal tunnel syndrome and 40 healthy controls. After identifying the participants, the serum levels of four cytokines (TNF-α, IL-2, IL-4, IL-6, and IL-10) were calculated by ELIZA method. SPSS statistical analysis was performed after entering data. p-values ≤ 0.05 was deliberated statistically significant.Results: The mean age was 45.07 ± 8.52 years in the patient group and 45.32 ± 8.42 years in the control group. The concentration of TNFα, IL1, IL6 and IL10 was 3.84 ± 0.44, 3.20 ± 0.71, 3.37 ± 1.26 and 6.21 ± 3.38 in patient group. The current study results demonstrated that there was no statistically significant difference among the case and control groups.Conclusions: This study showed that, serum levels of inflammatory cytokines (IL1, IL6, IL10 and TNFα) had no meaningful changes in patients with carpal tunnel syndrome and the role of these inflammatory mediators in this disease is still unclear.

Study of interleukin-6 and interleukin-8 levels in patients with neurological manifestations of dengue

Context:

Pro-inflammatory markers play a key role in the pathogenesis of various Flavivirus infection.

Aim:

In this study, we evaluated the role of these markers in neurological manifestations of dengue.

Settings and Designs:

Consecutive dengue cases with different neurological manifestations who presented between August 2012 and July 2014 were studied in hospital-based case–control study.

Materials and Methods:

Interleukin (IL-6) and IL-8 level were measured in serum and cerebrospinal fluid (CSF) of dengue cases with different neurological manifestations and also in age- and sex-matched controls. Level was analyzed with various parameters and outcomes.

Statistical Analysis:

Statistical analysis was done using SPSS version 16.0 by applying appropriate statistical methods. P < 0.05 considered statistically significant.

Results:

Out of the 40 enrolled cases of dengue with neurological manifestations, 29 had central nervous system and 11 had peripheral nervous system (CNS/PNS) manifestations. In CNS group, both IL-6 and IL-8 (CSF and serum) were significantly elevated (P < 0.001), whereas CSF IL-6 (P = 0.008), serum IL-6 (P = 0.001), and serum IL-8 (P = 0.005) were significantly elevated in PNS group. CSF IL-6, serum IL-6, and IL-8 were significantly elevated in poor outcome patients in CNS group (P < 0.05). CSF IL-6 and IL-8 were significantly elevated in CSF dengue positive cases as compared to CSF negative patients (P < 0.05). Cytokine level was not significantly correlated with neuroimaging abnormality in CNS group. Nine patients died and the remainder recovered.

Conclusion:

Elevated level of IL-6 and IL-8 is associated with different neurological manifestations and poor outcome, but whether they are contributing to neuropathogenesis or simply a correlate of severe disease remains to be determined.

Increased IP-10 production by blood-nerve barrier in multifocal acquired demyelinating sensory and motor neuropathy and multifocal motor neuropathy

OBJECTIVE

Dysfunction of the blood-nerve barrier (BNB) plays important roles in chronic inflammatory demyelinating polyneuropathy (CIDP) and multifocal motor neuropathy (MMN). The aim of the present study was to identify the candidate cytokines/chemokines that cause the breakdown of the BNB using sera from patients with CIDP and MMN.

METHODS

We determined the levels of 27 cytokines and chemokines in human peripheral nerve microvascular endothelial cells (PnMECs) after exposure to sera obtained from patients with CIDP variants (typical CIDP and multifocal acquired demyelinating sensory and motor neuropathy [MADSAM]), MMN and amyotrophic lateral sclerosis (ALS), and healthy controls (HC), using a multiplexed fluorescent bead-based immunoassay system.

RESULTS

The induced protein (IP)10 level in the cells in both the MADSAM and MMN groups was markedly increased in comparison with the typical CIDP, ALS and HC groups. The other cytokines, including granulocyte colony-stimulating factor,vascular endothelial growth factor (VEGF) and interleukin-7, were also significantly upregulated in the MADSAM group. The increase of IP-10 produced by PnMECs was correlated with the presence of conduction block in both the MADSAM and MMN groups.

CONCLUSION

The autocrine secretion of IP-10 induced by patient sera in PnMECs was markedly upregulated in both the MADSAM and MMN groups. The overproduction of IP-10 by PnMECs leads to the focal breakdown of the BNB and may help to mediate the transfer of pathogenic T cells across the BNB, thereby resulting in the appearance of conduction block in electrophysiological studies of patients with MADSAM and MMN.

Elevated resistin levels may regulate high mobility group box 1 expression in Guillain-Barré syndrome

Interactions among cytokines have important roles in the inflammatory processes underlying Guillain-Barré syndrome (GBS). Resistin and high mobility group box 1 (HMGB1) are involved in many inflammatory processes. This study examined 51 GBS patients, and found that serum resistin levels were elevated in 51 patients with GBS and correlated with HMGB1 levels. In vitro, resistin induced the release of HMGB1, interleukin (IL)-1β, and IL-6 in THP-1 macrophages. This process was dependent on activation of p38 mitogen-activated protein kinase and NF-κB signaling pathways. These results suggest that signaling between resistin and HMGB1 might be a potential therapeutic target in GBS.

Diagnostic insights into chronic-inflammatory demyelinating polyneuropathies

Chronic inflammatory demyelinating polyneuropathy (CIDP) is a rare immune-mediated neuropathy with demyelination of nerve fibers as leading morphological feature. The course of disease can be chronic progressive or remitting relapsing. Whereas for acute immune-mediated neuropathies several serological markers have been identified and used successfully in clinical routine, the serological diagnosis of chronic variants such as CIDP has not yet been evolved satisfactory. The typical CIDP and its various atypical variants are characterized by a certain diversity of clinical phenotype and response to treatment. Thus, diagnostic markers could aid in the differential diagnosis of CIDP variants and stratification of patients for a better treatment response. Most patients respond well to a causal therapy including steroids, intravenous immunoglobulins and plasmapheresis. Apart from electrophysiological and morphological markers, several autoantibodies have been reported as candidate markers for CIDP, including antibodies against glycolipids or paranodal/nodal molecules. The present review provides a summary of the progress in autoantibody testing in CIDP and its possible implication on the stratification of the CIDP variants and treatment response.

Immune dysregulation in patients with carpal tunnel syndrome

Peripheral immunity plays a key role in maintaining homeostasis and conferring crucial neuroprotective effects on the injured nervous system, while at the same time may contribute to increased vulnerability to neuropathic pain. Little is known about the reciprocal relationship between entrapment neuropathy and peripheral immunity. This study investigated immune profile in patients with carpal tunnel syndrome (CTS), the most prevalent entrapment neuropathy. All patients exhibited neurophysiological abnormalities in the median nerve, with the majority reporting neuropathic pain symptoms. We found a significant increase in serum CCL5, CXCL8, CXCL10 and VEGF, and in CD4+ central and effector memory T cells in CTS patients, as compared to healthy controls. CCL5 and VEGF were identified as having the highest power to discriminate between patients and controls. Interestingly, and contrary to the prevailing view of CCL5 as a pro-nociceptive factor, the level of circulating CCL5 was inversely correlated with neuropathic pain intensity and median nerve motor latency. In contrast, the level of central memory T cells was positively associated with abnormal neurophysiological findings. These results suggest that entrapment neuropathy is associated with adaptive changes in the homeostasis of memory T cells and an increase in systemic inflammatory modulating cytokines/chemokines, which potentially regulate neuropathic symptoms.

Increased serum concentrations of transforming growth factor-β1 (TGF-β1) in patients with Guillain-Barré syndrome

BACKGROUND

Guillain-Barré syndrome (GBS) is an acquired demyelinating peripheral neuropathy. It has shown that macrophage activation contribute to the pathogenesis of GBS. Therefore macrophage-mediated factors could be the potential markers for disease diagnosis and status of GBS.

METHODS

We measured serum concentrations of 4 macrophage-mediated factors, including interleukin-6 (IL-6), transforming growth factor-β1 (TGF-β1), vascular cell adhesion protein 1 (VCAM-1) and vascular endothelial growth factor (VEGF), in 23 chronic inflammatory demyelinating polyradiculoneuropathy (CIDP), 28 GBS, 11 Miller-Fisher syndrome (MFS), 40 multiple sclerosis (MS), and 12 Alzheimer's disease (AD) patients, as well as 15 healthy controls.

RESULTS

Serum TGF-β1 concentration of GBS patients (35.94±2.55ng/ml) was significantly higher compared with CIDP (25.46±1.40ng/ml, P<0.001), MFS (25.32±2.31ng/ml, P=0.010), MS (21.35±0.90ng/ml, P<0.001) and AD patients (22.92±1.82ng/ml, P<0.001), as well as healthy controls (23.12±1.67ng/ml, P<0.001). A positive correlation between serum TGF-β1 concentrations and Hughes' functional grading scales was observed in GBS patients. Serum concentrations of IL-6, VCAM-1 and VEGF were similar between the studied groups.

CONCLUSION

The high serum concentrations of TGF-β1 and the correlation between serum TGF-β1 concentration and disease severity highlight the potential of TGF-β1 as a biomarker of GBS.

Human Endogenous Retrovirus and Neuroinflammation in Chronic Inflammatory Demyelinating Polyradiculoneuropathy

BACKGROUND

Human endogenous retroviruses HERV-W encode a pro-inflammatory protein, named MSRV-Env from its original identification in Multiple Sclerosis. Though not detected in various neurological controls, MSRV-Env was found in patients with chronic inflammatory demyelinating polyradiculoneuropathies (CIDPs). This study investigated the expression of MSRV in CIDP and evaluated relevant MSRV-Env pathogenic effects.

METHODS

50 CIDP patients, 19 other neurological controls (ONDs) and 65 healthy blood donors (HBDs) were recruited from two different countries. MSRV-env and -pol transcripts, IL6 and CXCL10 levels were quantified from blood samples. MSRV-Env immunohistology was performed in distal sensory nerves from CIDP and neurological controls biopsies. MSRV-Env pathogenic effects and mode of action were assayed in cultured primary human Schwann cells (HSCs).

FINDINGS

In both cohorts, MSRV-env and -pol transcripts, IL6 positivity prevalence and CXCL10 levels were significantly elevated in CIDP patients when compared to HBDs and ONDs (statistically significant in all comparisons). MSRV-Env protein was detected in Schwann cells in 5/7 CIDP biopsies. HSC exposed to or transfected with MSRV-env presented a strong increase of IL6 and CXCL10 transcripts and protein secretion. These pathogenic effects on HSC were inhibited by GNbAC1, a highly specific and neutralizing humanized monoclonal antibody targeting MSRV-Env.

INTERPRETATION

The present study showed that MSRV-Env may trigger the release of critical immune mediators proposed as instrumental factors involved in the pathophysiology of CIDP. Significant MSRV-Env expression was detected in a significant proportion of patients with CIDP, in which it may play a role according to its presently observed effects on Schwann cells along with previously known effects on immune cells. Experimental results also suggest that a biomarker-driven therapeutic strategy targeting this protein with a neutralizing antibody such as GNbAC1 may offer new perspectives for treating CIDP patients with positive detection of MSRV-Env expression.

FUNDING

Geneuro-Innovation, France.

Inflammatory neuropathies: pathology, molecular markers and targets for specific therapeutic intervention

Inflammatory neuropathies encompass groups of heterogeneous disorders characterized by pathogenic immune-mediated hematogenous leukocyte infiltration of peripheral nerves, nerve roots or both, with resultant demyelination or axonal degeneration or both. Inflammatory neuropathies may be divided into three major disease categories: Guillain-Barré syndrome (particularly the acute inflammatory demyelinating polyradiculoneuropathy variant), chronic inflammatory demyelinating polyradiculoneuropathy and nonsystemic vasculitic neuropathy (or peripheral nerve vasculitis). Despite major advances in molecular biology, pathology and genetics, the pathogenesis of these disorders remains elusive. There is insufficient knowledge on the mechanisms of hematogenous leukocyte trafficking into the peripheral nervous system to guide the development of specific molecular therapies for immune-mediated inflammatory neuropathies compared to disorders such as psoriasis, inflammatory bowel disease, rheumatoid arthritis or multiple sclerosis. The recent isolation and characterization of human endoneurial endothelial cells that form the blood-nerve barrier provides an opportunity to elucidate leukocyte-endothelial cell interactions critical to the pathogenesis of inflammatory neuropathies at the interface between the systemic circulation and peripheral nerve endoneurium. This review discusses our current knowledge of the classic pathological features of inflammatory neuropathies, attempts at molecular classification and genetic determinants, the utilization of in vitro and in vivo animal models to determine pathogenic mechanisms at the interface between the systemic circulation and the peripheral nervous system relevant to these disorders and prospects for future potential molecular pathology biomarkers and targets for specific therapeutic intervention.

Variant Guillain-Barré Syndrome in a Patient with Non-Hodgkin's Lymphoma

We report a 72-year-old female patient with diffuse large B cell non-Hodgkin's lymphoma (NHL) with previous treatment with standard chemotherapy presenting as an acute, ascending, sensorimotor polyneuropathy. Nerve conduction studies and lumbar puncture supported a rare, but ominous, axonal variant of Guillain-Barré Syndrome (GBS) known as acute motor and sensory axonal neuropathy (AMSAN), which is distinguished from the more common, acute demyelinating forms of GBS. Previous reports have largely focused on toxicities secondary to chemo- or radiotherapy as a major contributor to the development of acute neuropathies in malignancy. Clinicians should also be mindful of direct neoplastic invasion or, less commonly, paraneoplastic phenomenon, as alternative mechanisms, the latter possibly reflecting immune dysregulation in particularly aggressive lymphomas. At the time of writing, this is the first report in the literature of an axonal variant of GBS in a patient with diffuse large B cell NHL. A discussion regarding common and uncommon neuropathies in haematological malignancies is made, with a brief review of the anecdotal evidence supporting a paraneoplastic association with GBS or its variant forms in the setting of lymphoma.

Differential gene expression of cytokines and neurotrophic factors in nerve and skin of patients with peripheral neuropathies

Pathophysiologically relevant alterations in cytokine and neurotrophic factor levels have been reported in neuropathy subtypes. We characterized gene expression profiles of pro- and anti-inflammatory cytokines and neurotrophic factors in nerve and skin samples of patients with neuropathies of different etiologies. We prospectively studied 133 patients with neuropathies and compared data between subtypes and with healthy controls. All patients underwent sural nerve and/or skin punch biopsy at the lateral thigh and lower leg; controls received skin punch biopsies. Gene expression of pro- and anti-inflammatory cytokines (IL-1β, IL-2, IL-6, TNF, IL-10), neurotrophic factors (BDNF, NGF, NT3, TrkA), and erythropoietin with the erythropoietin receptor (Epo, EpoR) was analyzed. Sural nerve gene expression of the investigated cytokines and neurotrophic factors did not differ between neuropathies of different etiologies; however, IL-6 (p < 0.01) and IL-10 (p < 0.05) expression was higher in painful compared to painless neuropathies. Skin IL-6 and IL-10 gene expression was increased in patients compared to controls (p < 0.05), and IL-10 expression was higher in lower leg skin of patients with non-inflammatory neuropathies compared to inflammatory neuropathies (p < 0.05). Proximal and distal skin neurotrophic factor and Epo gene expression of patients with neuropathies was reduced compared to controls (NGF, NT3, Epo; p < 0.05). Neuropathies are associated with an increase in cytokine expression and a decrease in neurotrophic factor expression including nerve and skin.

Circulating Th17, Th22, and Th1 cells are elevated in the Guillain-Barré syndrome and downregulated by IVIg treatments

The Guillain-Barré syndrome (GBS) is considered a T helper 1 (Th1) cells-mediated acute inflammatory peripheral neuropathy. However, some changes in GBS could not be explained completely by Th1 cells pathogenic role. Recently, Th17 cells have been identified and can mediate tissue inflammation and autoimmune response. Therefore, a study on the role of Th17 and Th22 cells and their cytokines in GBS is necessary for exploring the pathogenesis of GBS. Here, we detected the frequency of Th1, Th17, and Th22 cells by using 4-color flow cytometry and we detected the plasma levels of IL-17 and IL-22 by ELISA in GBS patients, relapsing-remitting multiple sclerosis patients at the acute phase of relapse, viral encephalitis or meningitis patients and healthy controls. Our data showed that the frequency of circulating Th1, Th17, and Th22 cells was significantly increased in GBS patients. The plasma levels of IL-17 and IL-22 in GBS and relapsing-remitting multiple sclerosis at the acute phase of relapse were also markedly elevated. Enhanced circulating Th22 cells were correlated with GBS severity. Intravenous immunoglobulin therapy downregulated Th17, and Th22 cells and the plasma levels of IL-17 and IL-22 in GBS patients. Th17 and Th22 cells may be involved in the pathogenesis of GBS, and intravenous immunoglobulin mediates therapeutic effects by downregulating these cells and their cytokines.

Recent developments and future directions in Guillain-Barré syndrome

Guillain-Barré syndrome (GBS) encompasses a spectrum of acquired neuropathic conditions characterized by inflammatory demyelinating or axonal peripheral neuropathy with acute onset. Clinical and experimental studies in the past years have led to substantial progress in epidemiology, pathogenesis of GBS variants, and identification of prognostic factors relevant to treatment. In this review we provide an overview and critical assessment of the most recent developments and future directions in GBS research.

Proinflammatory cytokines in serum and cerebrospinal fluid of CIDP patients

INTRODUCTION

Little is known about the role of cytokines in chronic inflammatory demyelinating polyradiculoneuropathy (CIDP). Interleukin (IL)-12 and IL-15 are the major growth and differentiation factors for Th-1 cells and IL-17 is a marker of Th-17 cell expansion and activation, a high proinflammatory new subset of T cells that induce severe autoimmunity.

PATIENTS AND METHODS

We measured by enzyme-like immunosorbent assay serum and cerebrospinal fluid (CSF) levels of IL-15, IL-12, and IL-17 in 24 patients with CIDP and 12 patients with other non-inflammatory neurological disorders and serum levels in 16 healthy subjects.

RESULTS

We found a positive association of CSF IL-12 (P = 0·012) with CIDP presence (P<0·001).

CONCLUSIONS

Our findings suggest that IL-12 may be involved as potential marker of immune activation in CIDP. The increase in its levels in CSF may be a marker of initiation of Th-1 cell-mediated immunity.

Advances in the diagnosis, pathogenesis and treatment of CIDP

Chronic inflammatory demyelinating polyneuropathy (CIDP) is the most common chronic autoimmune neuropathy. Despite clinical challenges in diagnosis-owing in part to the existence of disease variants, and different views on how many electrophysiological abnormalities are needed to document demyelination-consensus criteria seem to have been reached for research or clinical practice. Current standard of care involves corticosteroids, intravenous immunoglobulin (IVIg) and/or plasmapheresis, which provide short-term benefits. Maintenance therapy with IVIg can induce sustained remission, increase quality of life and prevent further axonal loss, but caution is needed to avoid overtreatment. Commonly used immunosuppressive drugs offer minimal benefit, necessitating the development of new therapies for treatment-refractory patients. Advances in our understanding of the underlying immunopathology in CIDP have identified new targets for future therapeutic efforts, including T cells, B cells, and transmigration and transduction molecules. New biomarkers and scoring systems represent emerging tools with the potential to predict therapeutic responses and identify patients with active disease for enrollment into clinical trials. This Review highlights the recent advances in diagnosing CIDP, provides an update on the immunopathology including new target antigens, and discusses current treatments, ongoing challenges and future therapeutic directions.

Distinct cytokine patterns associated with different forms of chronic dysimmune neuropathy

To better understand the presumed immune system dysregulation of chronic dysimmune neuropathy (CDN) patients, we designed a study to evaluate the levels of pro- and anti-inflammatory cytokines in the most common forms of CDN: chronic inflammatory demyelinating polyneuropathy (CIDP), and anti-myelin-associated glycoprotein (MAG)-related polyneuropathy (MAGnp). Sixteen patients fulfilled diagnostic criteria for CIDP, 14 were diagnosed with MAGnp, and 36 were classified as exhibiting "chronic idiopathic polyneuropathy" (CIP). Cytokine production in mitogen-stimulated peripheral blood mononuclear cells (PBMCs) was analyzed by flow cytometry. CIDP and MAGnp patients were compared with CIP patients, those with monoclonal gammopathy without polyneuropathy (MGUS), and healthy controls (HC). We observed an increase in pro-inflammatory cytokines in the CIDP group, whereas interleukin-10 (IL-10) was augmented in the MAGnp patients. These distinctive immune alterations may represent a biological tool in differential diagnosis and future therapeutic approaches.

TLR4-mediated sensing of Campylobacter jejuni by dendritic cells is determined by sialylation

In Guillain-Barré syndrome (GBS), ganglioside mimicry of Campylobacter jejuni lipo-oligosaccharide (LOS) drives the production of cross-reactive Abs to peripheral nerve gangliosides. We determined whether sialic acid residues in C. jejuni LOS modulate dendritic cell (DC) activation and subsequent B cell proliferation as a possible mechanism for the aberrant humoral immune response in GBS. Highly purified sialylated LOS of C. jejuni isolates from three GBS patients induced human DC maturation and secretion of inflammatory cytokines that were inhibited by anti-TLR4 neutralizing Abs. The extent of TLR4 signaling and DC activation was greater with LOS of the wild type isolates than with nonsialylated LOS of the corresponding sialyltransferase gene knockout (cst-II mutant) strains, indicating that sialylation boosts the DC response to C. jejuni LOS. Supernatants of LOS-activated DCs induced B cell proliferation after cross-linking of surface Igs in the absence of T cells. Lower B cell proliferation indices were found with DC supernatants after DC stimulation with cst-II mutant or neuraminidase desialylated LOS. This study showed that sialylation of C. jejuni LOS enhances human DC activation and subsequent B cell proliferation, which may contribute to the development of cross-reactive anti-ganglioside Abs found in GBS patients following C. jejuni infection.

Chronic inflammatory demyelinating polyradiculoneuropathy: diagnostic and therapeutic challenges for a treatable condition

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) is a chronic neuropathy of supposed immune origin. Understanding of its pathophysiology has recently improved, although its causes remain unclear. The classic presentation of CIDP includes sensory and motor symptoms in the distal and proximal segments of the four limbs with areflexia, evolving over more than 8 weeks. Raised protein concentrations in CSF and heterogeneous slowing of nerve conduction are typical of the condition. In addition to this usual phenotype, distribution of symptoms, disease course, and disability can be heterogeneous, leading to underdiagnosis of the disorder. Diagnosis is sometimes challenging and can require use of imaging and nerve biopsy. Steroids and intravenous immunoglobulin are effective, and plasma exchange can be helpful as rescue therapy. The usefulness of immunosuppressants needs to be established. The identification of specific diagnostic markers and new therapeutic strategies with conventional or targeted immunotherapy are needed to improve the outlook for patients with CIDP.

Lipopolysaccharide-induced inflammatory cytokine production by Schwann's cells dependent upon TLR4 expression

Signaling of Toll-like receptor-4 (TLR4) through its cognate ligand endotoxin appears critical in tissue inflammation associated with bacterial infection. We found that anti-GM1 antibody (Ab) enhances TLR4 expression in Schwann's cells (SCs) in vivo and in vitro. The anti-GM1 Ab-treated SC also showed increased release of pro-inflammation cytokines IL-1beta and TNF-alpha after incubation with lipopolysaccharide (LPS). Furthermore, down-regulation of TLR4 expression using antisense oligonucleotides targeted to TLR4 mRNA suppressed cytokine production in LPS stimulated cultures. These findings suggest that elevation of TLR4 expression increases sensitivity of SC to LPS and production of inflammatory mediators that may be responsible for peripheral nerve dysfunction.

Status of immune mediators in painful neuropathies

Peripheral neuropathies of identical etiology can be painful or painless. The reason for this difference in clinical presentation is as yet unknown; however, immune mediators, particularly cytokines, may play a role. Cytokines are proteins that are produced by immune and nonimmune cells and are categorized as pro- and anti-inflammatory. The role of cytokines in the induction and maintenance of pain has been well established in animal models. Proinflammatory cytokines are mostly algesic, whereas anti-inflammatory cytokines have analgesic properties. Clinical research also gives evidence for the involvement of cytokines in painful and painless neuropathies. A proinflammatory cytokine profile seems to be associated with pain in peripheral neuropathies of different etiologies and in other painful disorders such as the complex regional pain syndrome. Specifically, an imbalance between pro- and anti-inflammatory cytokines may contribute to pain generation. A better understanding of the underlying pathophysiology may open new opportunities for the treatment of pain.

Reduced levels of interleukin-1 receptor antagonist in the cerebrospinal fluid in patients with West syndrome

We measured the levels of pro- and anti-inflammatory cytokines in the cerebrospinal fluid (CSF) of 24 patients with West syndrome to clarify whether inflammatory cytokines were involved in the pathophysiology of West syndrome. There was no significant elevation of any of the three pro-inflammatory cytokines, interleukin (IL)-1beta, IL-6, and tumor necrosis factor-alpha, in patients with West syndrome as compared with those in controls. However, level of anti-inflammatory cytokine, IL-1 receptor antagonist was significantly decreased in the CSF of patients with West syndrome. Further study is needed to elucidate whether an immune system disturbance is involved in the pathophysiology of West syndrome.

Cardiac myxoma presenting with sensory neuropathy

A 51-year-old man was admitted for burning dysesthesias over the soles. Neurologic examination showed a pansensory loss over both feet associated with weakness of toes dorsiflexion. Motor conduction study of the sural nerve showed a significant reduction of nerve conduction velocity (21.4 m/s) suggesting a demyelinating neuropathy. In the following days he was referred to the cardiologist because of the sudden onset of a rapid atrial tachycardia, which was terminated by adenosine. Echocardiography showed a left atrial mass arising from the atrial septum consistent with the diagnosis of cardiac myxoma. The patient underwent cardiac surgery to remove the tumor, which was confirmed a myxoma by pathology. In the days following cardiac mass removal, neurological symptoms progressively disappeared in the absence of anti-inflammatory and steroid therapy and control motor conduction study showed complete normalization of nerve conduction velocity (54.5 m/s). Peripheral demyelinating neuropathy represented the first clinical presentation of cardiac myxoma in our patient and should be included among the possible paraneoplastic manifestations of this cardiac tumor.

Interleukin-1beta: a bridge between inflammation and excitotoxicity?

Interleukin-1 (IL-1) is a proinflammatory cytokine released by many cell types that acts in both an autocrine and/or paracrine fashion. While IL-1 is best described as an important mediator of the peripheral immune response during infection and inflammation, increasing evidence implicates IL-1 signaling in the pathogenesis of several neurological disorders. The biochemical pathway(s) by which this cytokine contributes to brain injury remain(s) largely unidentified. Herein, we review the evidence that demonstrates the contribution of IL-1beta to the pathogenesis of both acute and chronic neurological disorders. Further, we highlight data that leads us to propose IL-1beta as the missing mechanistic link between a potential beneficial inflammatory response and detrimental glutamate excitotoxicity.

Investigation of possible cytokine induction in peripheral blood mononuclear cells by heat-stable serotypes of Campylobacter jejuni

Several Campylobacter jejuni heat-stable (HS) serotypes have been associated with the autoimmune Guillain-Barre neurological syndrome (GBS). In order to examine the possible involvement of cytokines in this phenomenon, the levels of three pro-inflammatory cytokines (interleukin (IL)-2sRa, IL-6 and interferon (IFN)-gamma) and one anti-inflammatory cytokine (IL-10) were measured in peripheral blood mononuclear cells after induction by different C. jejuni serotypes. No differences were found for IL-6, IFN-gamma and IL-10, but the non-sialylated serotype HS:3 was associated with decreased production of IL-2sRa. The results raise the possibility that absence of sialylation might be associated with the inability to induce inflammatory factors such as cytokines.

Th1 shift in CIDP versus Th2 shift in vasculitic neuropathy in CSF

To investigate the intra- and extracellular levels of various cytokines and chemokines in CSF in chronic inflammatory demyelinating polyneuropathy (CIDP) and vasculitic neuropathy (VN), 16 cytokines, IL-1beta, IL-2, IL-4, IL-5, IL-6, IL-7, IL-8, IL-10, IL-12 (p70), IL-13, IL-17, IFN-gamma, TNF-alpha, G-CSF, MCP-1 and MIP-1beta, were measured in CSF supernatant by a multiplexed fluorescent bead-based immunoassay and intracellular production of IFN-gamma and IL-4 in CSF CD4+ T cells were simultaneously measured by flow cytometry in 14 patients with CIDP, 8 patients with VN and 25 patients with other noninflammatory neurologic diseases (OND). In the CSF supernatant, a significant increase of IL-17, IL-8 and IL-6, and a significant decrease of IL-4, IL-5 and IL-7 levels were detected in pretreated CIDP as compared with OND. A significant increase of IL-6, IL-8 and IL-10 levels was found in pretreated VN. Both IL-17 and IL-8 levels correlated strongly with CSF protein levels in CIDP, although the correlation of IL-6 levels was weak. In CSF CD4+ T cells, IFN-gamma+ IL-4- cell percentages were markedly elevated in CIDP compared with OND, but not in VN, resulting in a significant increase of intracellular IFN-gamma/IL-4 ratio in CIDP, even in the absence of CSF pleocytosis. The nonresponders to intravenous immunoglobulins (IVIGs) showed a significantly lower IFN-gamma- IL-4+ CD4+ T cell percentage, and tended to have a higher intracellular IFN-gamma/IL-4 ratio than the responders in CSF. Marked upregulation of Th1 cytokine, IL-17, and downregulation of Th2 cytokines, together with infiltration of IFN-gamma-producing CD4+ T cells are useful markers for CIDP, while several Th2 cytokines are upregulated in VN in CSF.

Soluble interleukin-6 receptor (sIL-6R) in cerebrospinal fluid of patients with inflammatory and non inflammatory neurological diseases

IL-6 acts on target cells via the ligand-binding protein interleukin-6 receptor (IL-6R) and the affinity-converting and signal-transducing glycoprotein 130 (gp130). Soluble interleukin-6 receptor (sIL-6R) has an agonistic role because the soluble complex (IL-6/sIL-6R) can activate cells that do not express IL-6R and an antagonistic role as it enhances the inhibitory activity of sgp130. Soluble forms of both receptors, sIL-6R and sgp130, regulate the action of IL-6. sIL-6R was measured by a sensitive enzyme-linked immunosorbent assay in paired sera and cerebrospinal fluid (CSF) from 46 patients with inflammatory neurological diseases (IND), 45 patients with relapsing-remitting multiple sclerosis (RR-MS), 13 patients with primary progressive multiple sclerosis (PP-MS), 17 patients with other non inflammatory neurological diseases (NIND) and 13 mentally healthy individuals--healthy controls (HC). Patients with RR-MS had CSF sIL-6R levels comparable to those from patients with IND, but higher than patients with NIND and HC. A positive correlation between the CSF/serum albumin (QAlb) and CSF sIL-6R levels was observed in IND but not in RR-MS patients indicating that CSF sIL-6R levels in IND patients could be influenced by serum sIL-6R and blood brain barrier (BBB) permeability properties. RR-MS patients had higher values of [CSF/serum sIL-6R:CSF/serum albumin] (sIL-6R index) than IND patients suggesting that in multiple sclerosis (MS), the increase in CSF sIL-6R could be due to intrathecal synthesis of sIL-6R. The finding of increased CSF sIL-6R concentrations (>979 pg/ml) with sIL-6R index (>4.66), in correlation with positive oligoclonal bands in RR-MS patients, suggests that values of sIL-6R index > 4.66 indicate intrathecal increase of sIL-6R and might be used as an indicator of neuroimmunoregulatory and inflammatory processes in the central nervous system (CNS).