IL-17 and IL-22 in cerebrospinal fluid and plasma are elevated in Guillain-Barré syndrome

Increased IL-22 in cerebrospinal fluid of neuro-behçet's disease patients

Remitting-Relapsing Multiple Sclerosis (RRMS) and Neuro-Behçet Disease (NBD) are two chronic neuro-inflammatory disorders leading to brain damage and disability in young adults. Herein, we investigated in these patients the cytokine response by beads-based multiplex assays during the early stages of these disorders. Cytokine investigations were carried out on treatment-naive patients suffering from RRMS and NBD recruited at the first episode of clinical relapse. Our findings demonstrate that Cerebrospinal Fluid (CSF) cells from NBD patients, but not RRMS, secrete significant high levels of IL-22 which is associated with elevated IL-22 mRNA expression. We also observed an increase in IL-22 levels in the definite NBD subgroup as compared to the probable NBD one, indicating a clear relationship between elevated IL-22 levels and diagnostic certainty. Interestingly, we found no correlation of IL-22 secretion between CSF and serum arguing about intrathecal release of IL-22 in the CNS of NBD patients. Moreover, we showed by correlogram analysis that this cytokine doesn't correlate with IL-17A, IL-17F and IL-21 suggesting that this cytokine is secreted by Th22 cells and not by Th17 cells in the CSF of NBD patients. Finally, we found elevated levels of IL-6 and a positive correlation between IL and 6 and IL-22 in the CSF of NBD. In conclusion, these results suggest that IL-6 contributes to the production of IL-22 by T cells leading to the exacerbation of inflammation and damage within the CNS of NBD patients.

Extensive cytokine biomarker analysis in serum of Guillain-Barré syndrome patients

Guillain-Barré syndrome (GBS) is an acute idiopathic polyneuropathy which is related to infection and immune mechanism. The exact pathogenesis of the disease is unknown and treatment is limited. Thus, the purpose of the study is to identify biomarkers of GBS serum and elucidate their involvement in the underlying pathogenesis of GBS that could help to treat GBS more accurately. Antibody array technology was used to detect the expression levels of 440 proteins in serum of 5 GBS group and 5 healthy control group. Sixty-seven differentially expressed proteins (DEPs) were identified by antibody array, among which FoLR1, Legumain, ErbB4, IL-1α, MIP-1α and IGF-2 were down-regulated, while 61 proteins were up-regulated. Bioinformatics analysis indicated that most DEPs were associated with leukocytes, among which IL-1α, SDF-1b, B7-1, CD40, CTLA4, IL-9, MIP-1α and CD40L were in the center of protein-protein interaction (PPI) network. Subsequently, the ability of these DEPs to distinguish GBS from healthy control was further evaluated. CD23 was identified by means of Random Forests Analysis (RFA) and verified by enzyme-linked immunosorbent assay (ELISA). The ROC curve result of CD23 respectively displayed that its sensitivity, specificity and AUC were 0.818, 0.800 and 0.824. We speculate that activation of leukocyte proliferation and migration in circulating blood might be associated with inflammatory recruitment of peripheral nerves, leading to the occurrence and development of GBS, but this conclusion still requires deeper confirmation. More importantly, central proteins may play a pivotal role in the pathogenesis of GBS. In addition, we detected IL-1α, IL-9, and CD23 in the serum of GBS patients for the first time, which may be promising biomarkers for the treatment of GBS.

IL-22 Promotes Neural Stem Cell Self-Renewal in the Adult Brain

Mainly known for its role in immune defense and inflammation, interleukin 22 (IL-22) has emerged over the past decade as a cytokine involved in the adaptation of stem/progenitor cell activity for tissue homeostasis and repair. IL-22 is present in the brain, which harbors neural stem cells (NSC) in specific niches of which the ventricular-subventricular zone (V-SVZ) is the most important. In this study, we examined a possible effect of IL-22 on NSC in the adult mouse brain. We demonstrate that the IL-22 receptor is expressed in the V-SVZ, mainly in NSC characterized by their SOX2 expression. Addition of IL-22 to V-VSZ cell cultures resulted in an increase in NSC self-renewal, associated with a shift in NSC division mode towards symmetric proliferative divisions at the expense of differentiative divisions. Conversely, loss of IL-22 in knockout mice led to a decrease in neurosphere yield, suggesting a reduction in the NSC population, which was confirmed by the decrease in cells retaining BrdU labeling in IL-22 knockout mice. Our study supports that IL-22 is involved in the development and/or maintenance of V-VSZ NSC and opens new avenues to further investigate the role of IL-22 in NSC biology in health and disease.

Role of Th17 and IL-17 Cytokines on Inflammatory and Auto-immune Diseases

BACKGROUND

The IL-17 (interleukin 17) family consists of six structurally related pro-inflammatory cytokines, namely IL-17A to IL-17F. These cytokines have garnered significant scientific interest due to their pivotal role in the pathogenesis of various diseases. Notably, a specific subset of T-cells expresses IL-17 family members, highlighting their importance in immune responses against microbial infections.

INTRODUCTION

IL-17 cytokines play a critical role in host defense mechanisms by inducing cytokines and chemokines, recruiting neutrophils, modifying T-cell differentiation, and stimulating the production of antimicrobial proteins. Maintaining an appropriate balance of IL-17 is vital for overall health. However, dysregulated production of IL-17A and other members can lead to the pathogenesis of numerous inflammatory and autoimmune diseases.

METHOD

This review provides a comprehensive overview of the IL-17 family and its involvement in several inflammatory and autoimmune diseases. Relevant literature and research studies were analyzed to compile the data presented in this review.

RESULTS

IL-17 cytokines, particularly IL-17A, have been implicated in the development of various inflammatory and autoimmune disorders, including multiple sclerosis, Hashimoto's thyroiditis, systemic lupus erythematosus, pyoderma gangrenosum, autoimmune hepatic disorders, rheumatoid arthritis, psoriasis, psoriatic arthritis, ankylosing spondylitis, osteoarthritis, and graft-versus-host disease. Understanding the role of IL-17 in these diseases is crucial for developing targeted therapeutic strategies.

CONCLUSION

The significant involvement of IL-17 cytokines in inflammatory and autoimmune diseases underscores their potential as therapeutic targets. Current treatments utilizing antibodies against IL-17 cytokines and IL-17RA receptors have shown promise in managing these conditions. This review consolidates the understanding of IL-17 family members and their roles, providing valuable insights for the development of novel immunomodulators to effectively treat inflammatory and autoimmune diseases.

CCL21 contributes to Th17 cell migration in neuroinflammation in obese mice following lead exposure

Obesity and lead exposure can independently cause neuroinflammation, which is associated with neurodegenerative diseases. Although Th17 cells play critical roles in inflammatory diseases of the central nervous system, few studies have evaluated their role in neuroinflammation in the background of obesity and lead exposure. In this study, the mechanism underlying inflammatory injury was evaluated in a mouse model of high fat diet-induced obesity following lead exposure. Neuroinflammation was aggravated in mice with obesity following lead exposure, and this was accompanied by increases in Th17 cells in the brain and IL-17A and IL-22 secretion. An antibody array using Z310, a choroid plexus epithelium cell line, revealed that CCL21 was the most highly altered chemokine. CCL21 expression was higher in the choroid plexus of obese mice treated with lead than in mice with obesity or lead treatment alone and was higher in Z310 cells treated with lead and palmitic acid. CCL21 knockout reduced chemotaxis. Our findings suggest that lead exposure can aggravate inflammation in brain tissues of obese mice, possibly by the CCL21-mediated regulation of the passage of Th17 cells through the blood-cerebrospinal fluid barrier. Our findings provide new insights into the mechanism underlying the combined effects of lead and obesity.

IL-22 inhibits bleomycin-induced pulmonary fibrosis in association with inhibition of IL-17A in mice

BACKGROUND

Interstitial lung disease, a common extra-articular complication of connective tissue disease, is characterized by progressive and irreversible pulmonary inflammation and fibrosis, which causes significant mortality. IL-22 shows a potential in regulating chronic inflammation and possibly plays an anti-fibrotic role by protecting epithelial cells. However, the detailed effects and underlying mechanisms are still unclear. In this study, we explored the impact of IL-22 on pulmonary fibrosis both in vivo and in vitro.

METHODS

To induce pulmonary fibrosis, wild-type mice and IL-22 knockout mice were intratracheally injected with bleomycin followed by treatments with recombinant IL-22 or IL-17A neutralizing antibody. We investigated the role of IL-22 on bleomycin-induced pulmonary fibrosis and the mechanism in the possible interaction between IL-22 and IL-17A. Fibrosis-related genes were detected using RT-qPCR, western blot, and immunofluorescence. Inflammatory and fibrotic changes were assessed based on histological features. We also used A549 human alveolar epithelial cells, NIH/3T3 mouse fibroblast cells, and primary mouse lung fibroblasts to study the impact of IL-22 on fibrosis in vitro.

RESULTS

IL-22 knockout mice showed aggravated pulmonary fibrosis compared with wild-type mice, and injection of recombinant IL-22 decreased the severe fibrotic manifestations in IL-22 knockout mice. In cell culture assays, IL-22 decreased protein levels of Collagen I in A549 cells, NIH/3T3 cells, and primary mouse lung fibroblasts. IL-22 also reduced the protein level of Collagen I in NIH/3T3 cells which were co-cultured with T cells. Mechanistically, IL-22 reduced the Th17 cell proportion and IL-17A mRNA level in lung tissues, and treatment with an IL-17A neutralizing antibody alleviated the severe pulmonary fibrosis in IL-22 knockout mice. The IL-17A neutralizing antibody also reduced Collagen I expression in NIH/3T3 cells in vitro. Knockdown of IL-17A with siRNAs or administration of IL-22 in NIH/3T3 cells and MLFs decreased expression of Collagen I, an effect blocked by concurrent use of recombinant IL-17A.

CONCLUSIONS

IL-22 mediated an anti-fibrogenesis effect in the bleomycin-induced pulmonary fibrosis model and this effect was associated with inhibition of IL-17A.

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 Endocannabinoid System: A Potential Target for the Treatment of Various Diseases

The Endocannabinoid System (ECS) is primarily responsible for maintaining homeostasis, a balance in internal environment (temperature, mood, and immune system) and energy input and output in living, biological systems. In addition to regulating physiological processes, the ECS directly influences anxiety, feeding behaviour/appetite, emotional behaviour, depression, nervous functions, neurogenesis, neuroprotection, reward, cognition, learning, memory, pain sensation, fertility, pregnancy, and pre-and post-natal development. The ECS is also involved in several pathophysiological diseases such as cancer, cardiovascular diseases, and neurodegenerative diseases. In recent years, genetic and pharmacological manipulation of the ECS has gained significant interest in medicine, research, and drug discovery and development. The distribution of the components of the ECS system throughout the body, and the physiological/pathophysiological role of the ECS-signalling pathways in many diseases, all offer promising opportunities for the development of novel cannabinergic, cannabimimetic, and cannabinoid-based therapeutic drugs that genetically or pharmacologically modulate the ECS via inhibition of metabolic pathways and/or agonism or antagonism of the receptors of the ECS. This modulation results in the differential expression/activity of the components of the ECS that may be beneficial in the treatment of a number of diseases. This manuscript in-depth review will investigate the potential of the ECS in the treatment of various diseases, and to put forth the suggestion that many of these secondary metabolites of Cannabis sativa L. (hereafter referred to as "C. sativa L." or "medical cannabis"), may also have potential as lead compounds in the development of cannabinoid-based pharmaceuticals for a variety of diseases.

Neutrophil-to-lymphocyte and platelet-to-lymphocyte ratios as inflammation markers in patients with papilledema due to idiopathic intracranial hypertension

Purpose:

The aim of this study was to investigate the role of inflammation in the pathogenesis of idiopathic intracranial hypertension (IIH) using the neutrophil-to-lymphocyte ratio (NLR) and platelet-to-lymphocyte ratio (PLR) as inflammation markers.

Methods:

The files of 33 IIH patients and 33 controls were screened for this retrospective study. For each patient, the NLR and PLR values were calculated using a single fasting blood sample. For both eyes, papilledema (PE) grades, best-corrected visual acuity (BCVA), retinal nerve fiber layer thickness (RNFLT), and ganglion cell layer thickness (GCLT) measurements were recorded along with the demographic data, including body mass index (BMI), and complete neurological and ophthalmological findings. Comparisons between the two groups and between the IIH patients with and without PE were made. The associations of NLR and PLR with all other parameters were analyzed independently from age, gender, and BMI.

Results:

NLR and PLR were higher in patients with IIH than controls (P < 0.05). They were also higher in patients with PE (P < 0.05) in the IIH group. NLR and PLR were found to be associated with BCVA (P < 0.001 and P = 0.023, respectively), global RNFLT (P = 0.004 and 0.012, respectively), RNFLT of the temporal quadrant (P < 0.001 and P = 0.042, respectively) and PE grade (P < 0.001 and P = 0.035, respectively).

Conclusion:

The NLR and PLR values and their associations with BCVA, RNFLT, and PE support the hypothesis that inflammation is a very important component of the pathogenesis of IIH.

SARS-CoV-2 Infection and Guillain-Barré Syndrome: A Review on Potential Pathogenic Mechanisms

Since December 2019, the world has been facing an outbreak of a new disease called coronavirus disease 2019 (COVID-19). The COVID-19 pandemic is caused by a novel beta-coronavirus named severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The SARS-CoV-2 infection mainly affects the respiratory system. Recently, there have been some reports of extra-respiratory symptoms such as neurological manifestations in COVID-19. According to the increasing reports of Guillain-Barré syndrome following COVID-19, we mainly focused on SARS-CoV-2 infection and Guillain-Barré syndrome in this review. We tried to explain the possibility of a relationship between SARS-CoV-2 infection and Guillain-Barré syndrome and potential pathogenic mechanisms based on current and past knowledge.

The therapeutic effects of ginkgolides in Guillain-Barré syndrome and experimental autoimmune neuritis

BACKGROUND

Guillain-Barré syndrome (GBS) is an acquired immune-mediated inflammatory peripheral neuropathy. The immune regulation of ginkgolides have been revealed in recent years. We herein investigate the potential therapeutic effects of ginkgolides both on GBS and its animal model, experimental autoimmune neuritis (EAN).

METHODS

EAN in C57BL/6 mice induced by subcutaneous injection with peripheral nerve myelin P0 protein peptide 180-199 (P0 peptide) were treated with ginkgolides at three different doses. GBS patients were randomly divided into two groups, the experimental group and the control group. The experimental group were treated with ginkgolides as soon as diagnosed.

RESULTS

Our data indicated that ginkgolides administration daily ameliorated the score of EAN and delayed the peak of disease in EAN mice. Ginkgolides also down-regulated the proportions of T helper (Th) 17 cells in EAN spleens. Furthermore, we also found that administration of ginkgolides significantly decreased the levels of interferon (IFN)-γ and interleukin-12 (IL)-12 in GBS patients.

CONCLUSIONS

Our results suggested that ginkgolides ameliorated the clinical score of EAN through down-regulating the proportions of Th 17 cells. Ginkgolides also suppressed inflammation response by decreasing pro-inflammatory cytokines IFN-γ and IL-12, suggesting ginkgolides had potential therapeutic effects on GBS patients and EAN in the future.

The role of inflammatory mediators in epilepsy: Focus on developmental and epileptic encephalopathies and therapeutic implications

In recent years, there has been an increasing interest in the potential involvement of neuroinflammation in the pathogenesis of epilepsy. Specifically, the role of innate immunity (that includes cytokines and chemokines) has been extensively investigated either in animal models of epilepsy and in clinical settings. Developmental and epileptic encephalopathies (DEE) are a heterogeneous group of epileptic disorders, in which uncontrolled epileptic activity results in cognitive, motor and behavioral impairment. By definition, epilepsy in DEE is poorly controlled by common antiepileptic drugs but may respond to alternative treatments, including steroids and immunomodulatory drugs. In this review, we will focus on how cytokines and chemokines play a role in the pathogenesis of DEE and why expanding our knowledge about the role of neuroinflammation in DEE may be crucial to develop new and effective targeted therapeutic strategies to prevent seizure recurrence and developmental regression.

The Neuroimmunology of Guillain-Barré Syndrome and the Potential Role of an Aging Immune System

Guillain-Barré syndrome (GBS) is a paralyzing autoimmune condition affecting the peripheral nervous system (PNS). Within GBS there are several variants affecting different aspects of the peripheral nerve. In general, there appears to be a role for T cells, macrophages, B cells, and complement in initiating and perpetuating attacks on gangliosides of Schwann cells and axons. Of note, GBS has an increased prevalence and severity with increasing age. In addition, there are alterations in immune cell functioning that may play a role in differences in GBS with age alongside general age-related declines in reparative processes (e.g., delayed de-differentiation of Schwann cells and decline in phagocytic ability of macrophages). The present review will explore the immune response in GBS as well as in animal models of several variants of the disorder. In addition, the potential involvement of an aging immune system in contributing to the increased prevalence and severity of GBS with age will be theorized.

Altered serum levels of IL-36 cytokines (IL-36α, IL-36β, IL-36γ, and IL-36Ra) and their potential roles in Guillain-Barré syndrome

Guillain-Barré syndrome (GBS) is an acute autoimmune neurological disorder mainly involving the peripheral nerves. Currently, various cytokines have been shown to be involved in the pathogenesis of GBS. Because of their similar biological structures, interleukin (IL)-36α, IL-36β, IL-36γ, and IL-36 receptor antagonist (Ra) were all renamed and collectively called IL-36 cytokines. The roles of IL-36 cytokines in GBS currently remain unclear.Forty-two patients with GBS and 32 healthy volunteers were included in our study. Serum IL-36α, β, γ, and interleukin-36 receptor antagonist (IL-36Ra) levels of patients with GBS in the acute and remission phases and healthy volunteers were measured by enzyme-linked immunosorbent assay (ELISA). In addition, we examined the serum levels of other inflammatory factors that have been shown to be involved in GBS pathogenesis, represented by IL-17 and tumor necrosis factor-α (TNF-α). Furthermore, the correlations between the serum levels of IL-36 cytokines and different clinical data or the serum levels of other inflammatory factors in GBS patients were analyzed.Significantly higher serum IL-36α and IL-36γ levels were measured in the acute phase than in the remission phase and in healthy control (HC) subjects (P < .05), while lower serum IL-36Ra levels were measured in the acute phase than in the remission phase and in HC subjects (P < .05). Serum IL-36α and IL-36γ levels were positively correlated with GBS disability scale scores (GDSs), while serum IL-36Ra levels were negatively correlated with GDSs. Correlation analyses among inflammatory factors showed that serum IL-36α and IL-36γ levels in GBS patients were positively correlated with serum IL-17 and TNF-α levels, while serum IL-36Ra levels were negatively correlated with the levels of these 2 inflammatory factors. Similar results were observed in cerebrospinal fluid (CSF), IL-36α and IL-36γ levels in CSF were positively correlated with GDSs, while IL-36Ra levels in CSF were negatively correlated with GDSs. Additionally, the serum and CSF levels of IL-36α and IL-36γ in the axonal subtype of GBS patients were higher than those in the demyelination subtype.Based on our findings, IL-36 cytokines may be involved in the pathogenesis of GBS and some of these cytokines may help predict the disease severity and other clinical characteristics of GBS.

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.

Interleukin-22 Polymorphisms in Plasmodium falciparum-Infected Malaria Patients

Background and Objectives. Malaria infection, caused by Plasmodium falciparum, is the most lethal and frequently culminates in severe clinical complications. Interleukin-22 (IL-22) has been implicated in several diseases including malaria. The objective of this study was to investigate the role of IL-22 gene polymorphisms in P. falciparum infection. Material and Methods. Ten single-nucleotide polymorphisms (SNPs), rs976748, rs1179246, rs2046068, rs1182844, rs2227508, rs2227513, rs2227478, rs2227481, rs2227491, and rs2227483, of IL-22 gene were genotyped through PCR-based assays of 250 P. falciparum infection. IL-22 gene promoter activity.

RESULTS

We found that the rs2227481 TT genotype (odds ratio 0.254, confidence interval = 0.097-0.663, P. P. falciparum infection. P. P. P. P.

CONCLUSION

The study suggests that IL-22 polymorphisms in rs2227481 and rs2227483 could contribute to protection against P. falciparum infection. IL-22 gene promoter activity.

Cerebrospinal fluid dynamics modulation by diet and cytokines in rats

Background

Idiopathic intracranial hypertension (IIH) is a neurological disorder characterised by raised cerebrospinal fluid (CSF) pressure in the absence of any intracranial pathology. IIH mainly affects women with obesity between the ages of 15 and 45. Two possible mechanisms that could explain the increased CSF pressure in IIH are excessive CSF production by the choroid plexus (CP) epithelium or impaired CSF drainage from the brain. However, the molecular mechanisms controlling these mechanisms in IIH remain to be determined.

Methods

In vivo ventriculo-cisternal perfusion (VCP) and variable rate infusion (VRI) techniques were used to assess changes in rates of CSF secretion and resistance to CSF drainage in female and male Wistar rats fed either a control (C) or high-fat (HF) diet (under anaesthesia with 20 μl/100 g medetomidine, 50 μl/100 g ketamine i.p). In addition, CSF secretion and drainage were assessed in female rats following treatment with inflammatory mediators known to be elevated in the CSF of IIH patients: C–C motif chemokine ligand 2 (CCL2), interleukin (IL)-17 (IL-17), IL-6, IL-1β, tumour necrosis factor-α (TNF-α), as well as glucocorticoid hydrocortisone (HC).

Results

Female rats fed the HF diet had greater CSF secretion compared to those on control diet (3.18 ± 0.12 μl/min HF, 1.49 ± 0.15 μl/min control). Increased CSF secretion was seen in both groups following HC treatment (by 132% in controls and 114% in HF) but only in control rats following TNF-α treatment (137% increase). The resistance to CSF drainage was not different between control and HF fed female rats (6.13 ± 0.44 mmH₂O min/μl controls, and 7.09 ± 0.26 mmH₂O min/μl HF). and when treated with CCL2, both groups displayed an increase in resistance to CSF drainage of 141% (controls) and 139% (HF) indicating lower levels of CSF drainage.

Conclusions

Weight loss and therapies targeting HC, TNF-α and CCL2, whether separately or in combination, may be beneficial to modulate rates of CSF secretion and/or resistance to CSF drainage pathways, both factors likely contributing to the raised intracranial pressure (ICP) observed in female IIH patients with obesity.

Soluble CD146, a cerebrospinal fluid marker for neuroinflammation, promotes blood-brain barrier dysfunction

The blood-brain barrier (BBB) dysfunction is an initial event of various neuroinflammatory diseases. However, the absence of reliable markers and mechanisms for BBB damage greatly limits the diagnosis and treatment of neuroinflammatory diseases. Soluble CD146 (sCD146) is mainly derived from vascular endothelial cells (ECs) and highly elevated in inflammatory settings. Based on a small cohort, our previous study showed that sCD146 is elevated in the cerebrospinal fluid (CSF) of multiple sclerosis (MS), which is accompanied with BBB damage. Nevertheless, whether sCD146 monitors and regulates the BBB dysfunction remains unknown.

Methods: Coupled serum and CSF samples from patients with or without neuroinflammatory diseases were collected via multicenter collaborations. sCD146 was measured by sandwich ELISA using anti-CD146 antibodies AA1 and AA98, both of which were generated in our laboratory. The correlations between sCD146 and other clinical parameters or inflammatory factors were analyzed by Spearman's correlation coefficient analysis. The role of sCD146 on BBB function was examined in an in vitro BBB model.

Results: Between July 20, 2011, and February 31, 2017, we collected coupled serum and CSF samples from 823 patients, of which 562 (68.3%) had neuroinflammatory diseases, 44 (5.3%) had remitting MS, and 217 (26.4%) had non-inflammatory neurological diseases (NIND). We found that sCD146 in CSF, but not in serum, is abnormally elevated in neuroinflammatory diseases (37.3 ± 13.3 ng/mL) compared with NIND (4.7 ± 2.9 ng/mL) and remitting MS (4.6 ± 3.5 ng/mL). Abnormally elevated CSF sCD146 is significantly correlated with the hyperpermeability-related clinical parameters of BBB and neuroinflammation-related factors. Moreover, CSF sCD146 shows higher sensitivity and specificity for evaluating BBB damage. Using an in vitro BBB model, we found that sCD146 impairs BBB function by promoting BBB permeability via an association with integrin αvβ1. Blocking integrin αvβ1 significantly attenuates sCD146-induced hyperpermeability of the BBB.

Conclusion: Our study provides convincing evidence that CSF sCD146 is a sensitive marker of BBB damage and neuroinflammation. Furthermore, sCD146 is actively involved in BBB dysfunction.

Th17 cells and their cytokines serve as potential therapeutic target in experimental autoimmune neuritis

BACKGROUND

Accumulating evidence has pointed that T helper 17 cells and their cytokines are pathogenic in Guillain-Barré syndrome (GBS). However, little is known concerning the IL-17 expression change trend during the whole course of disease, and whether drugs specially targeting Th17 cells or their cytokines have potential effects on experimental autoimmune neuritis (EAN) is uncertain.

METHODS

We explored the IL-17 and receptor-related orphan receptor-gamma-t (RORγt) expression change trends in EAN rats to identify the stage of effect of Th17 pathway in EAN, and further, we investigated the effect of RORγt inhibitors by assessing clinical score, histological staining, and IL-17 and RORγt expression change trends in serum and tissues.

RESULTS

The expression level of IL-17 and RORγt in serum and tissues increased with the progression of the disease in the EAN group and decreased after the disease reaching its peak. RORγt-IN-1 treatment strikingly reduced the neurological deficits by ameliorating inflammatory cell infiltration, deceased the serum IL-17 and RORγt levels, and further downregulated the expression of IL-17 and RORγt mRNA in spleen, lymphnodes, and sciatic nerve.

CONCLUSIONS

Th17 cells and their cytokines are closely associated with the onset of GBS and the novel RORγt inhibitors may be prospective strategies in treating GBS.

Roles of Neuropeptide Y in Neurodegenerative and Neuroimmune Diseases

Neuropeptide Y (NPY) is a neurotransmitter or neuromodulator that mainly exists in the nervous system. It plays a neuroprotective role in organisms and widely participates in the regulation of various physiological processes in vivo. Studies in both humans and animal models have been revealed that NPY levels are altered in some neurodegenerative and neuroimmune disorders. NPY plays various roles in these diseases, such as exerting a neuroprotective effect, increasing trophic support, decreasing excitotoxicity, regulating calcium homeostasis, and attenuating neuroinflammation. In this review, we will focus on the roles of NPY in the pathological mechanisms of neurodegenerative and neuroimmune diseases, highlighting NPY as a potential therapeutic target in these diseases.

Alopecia areata is characterized by dysregulation in systemic type 17 and type 2 cytokines, which may contribute to disease-associated psychological morbidity

BACKGROUND

Alopecia areata (AA) is a common autoimmune disease, causing patchy hair loss that can progress to involve the entire scalp (totalis) or body (universalis). CD8⁺ NKG2D⁺ T cells dominate hair follicle pathogenesis, but the specific mechanisms driving hair loss are not fully understood.

OBJECTIVES

To provide a detailed insight into the systemic cytokine signature associated with AA, and to assess the association between cytokines and depression.

METHODS

We conducted multiplex analysis of plasma cytokines from patients with AA, patients with psoriatic arthritis (PsA) and healthy controls. We used the Hospital Anxiety and Depression Scale (HADS) to assess the occurrence of depression and anxiety in our cohort.

RESULTS

Our analysis identified a systemic inflammatory signature associated with AA, characterized by elevated levels of interleukin (IL)-17A, IL-17F, IL-21 and IL-23 indicative of a type 17 immune response. Circulating levels of the type 2 cytokines IL-33, IL-31 and IL-17E (IL-25) were also significantly increased in AA. In comparison with PsA, AA was associated with higher levels of IL-17F, IL-17E and IL-23. We hypothesized that circulating inflammatory cytokines may contribute to wider comorbidities associated with AA. Our assessment of psychiatric comorbidity in AA using HADS scores showed that 18% and 51% of people with AA experienced symptoms of depression and anxiety, respectively. Using linear regression modelling, we identified that levels of IL-22 and IL-17E are positively and significantly associated with depression.

CONCLUSIONS

Our data highlight changes in both type 17 and type 2 cytokines among people with AA, suggesting that complex systemic cytokine profiles may contribute both to the pathogenesis of AA and to the associated depression. What's already known about this topic? NKG2D⁺ CD8⁺ T cells cause hair loss in alopecia areata (AA) but the immunological mechanisms underlying the disease are not fully understood. AA is associated with changes in levels of interleukin (IL)-6, tumour necrosis factor-α, IL-1β and type 17 cytokines. Psychiatric comorbidity is common among people with AA. What does this study add? People with AA have increased plasma levels of the type 2 cytokines IL-33, IL-31 and IL-17E (IL-25), in addition to the type 17 cytokines IL-17A, IL-21, IL-23 and IL-17F. Levels of IL-17E and IL-22 positively predict depression score. What is the translational message? AA is associated with increased levels of multiple inflammatory cytokines, implicating both type 17- and type 2 immune pathways. Our data indicate that therapeutic strategies for treating AA may need to address the underlying type 17- and type 2 immune dysregulation, rather than focusing narrowly on the CD8⁺ T-cell response. An immunological mechanism might contribute directly to the depression observed in people with AA.

Peripheral Blood and Cerebrospinal Fluid Cytokine Levels in Guillain Barré Syndrome: A Systematic Review and Meta-Analysis

Background: Guillain Barré Syndrome (GBS) is an autoimmune disorder caused by the immune-mediated damage of the peripheral nervous system. Increasing evidence suggests that inflammatory cytokines are important mediators for the onset and progression of GBS. A number of clinical studies have demonstrated elevated levels of T helper-1 (Th1-), Th2-, and Th17-related cytokines in patients with GBS; however, the results were inconsistent across studies.

Methods: We performed a systematic review and a meta-analysis of studies comparing the levels of inflammatory cytokines in the cerebrospinal fluid and peripheral blood between patients with GBS and healthy individuals, using Comprehensive Meta-Analysis Version 2 software. A database search identified 30 studies comprising 1,302 patients with GBS and 1,073 healthy controls.

Results: The random-effects meta-analysis demonstrated that peripheral blood tumor necrosis factor-α (Hedges g, 1.544; 95% confidence interval (CI), 0.923–2.165; p < 0.001), interleukin-1β (IL-1β; Hedges g, 0.678; 95% CI, 0.183–1.172; p = 0.007), IL-6 (Hedges g, 0.630; 95% CI, 0.100–1.160; p = 0.02), IL-4 (Hedges g, 0.822; 95% CI, 0.220–1.423; p = 0.007), IL-17 (Hedges g, 1.452; 95% CI, 0.331–2.573; p = 0.011), interferon-γ (Hedges g, 1.104; 95% CI, 0.490–1.719; p < 0.001), and C-reactive protein (Hedges g, 0.909; 95% CI, 0.453–1.365; p < 0.001) levels were significantly increased in patients with GBS when compared with healthy controls. Contrastingly, the blood IL-10 and transforming growth factor-β levels were not significantly associated with GBS. Furthermore, the meta-analysis found that cerebrospinal fluid IL-17 levels were significantly associated with GBS (Hedges g, 1.882; 95% CI, 0.104–3.661; p = 0.038).

Conclusion: Altogether, our results clarified the circulating inflammatory cytokine profile in patients with GBS, and revealed that Th1-, Th2-, and Th17-related cytokines were highly elevated in the GBS patients, suggesting the potential use of these cytokines as biomarkers for GBS.

Immune Cell Profiling of the Cerebrospinal Fluid Provides Pathogenetic Insights Into Inflammatory Neuropathies

Objective: Utilize immune cell profiles in the cerebrospinal fluid (CSF) to advance the understanding and potentially support the diagnosis of inflammatory neuropathies.

Methods: We analyzed CSF cell flow cytometry data of patients with definite Guillain-Barré syndrome (GBS, n = 26) and chronic inflammatory demyelinating polyneuropathy (CIDP, n = 32) based on established diagnostic criteria in comparison to controls with relapsing-remitting multiple sclerosis (RRMS, n = 49) and idiopathic intracranial hypertension (IIH, n = 63).

Results: Flow cytometry revealed disease-specific changes of CSF cell composition with a significant increase of NKT cells and CD8+ T cells in CIDP, NK cells in GBS, and B cells and plasma cells in MS in comparison to IIH controls. Principal component analysis demonstrated distinct CSF immune cells pattern in inflammatory neuropathies vs. RRMS. Systematic receiver operator curve (ROC) analysis identified NKT cells as the best parameter to distinguish GBS from CIDP. Composite scores combing several of the CSF parameters differentiated inflammatory neuropathies from IIH and GBS from CIDP with high confidence. Applying a novel dimension reduction technique, we observed an intra-disease heterogeneity of inflammatory neuropathies.

Conclusion: Inflammatory neuropathies display disease- and subtype-specific alterations of CSF cell composition. The increase of NKT cells and CD8+ T cells in CIDP and NK cells in GBS, suggests a central role of cytotoxic cell types in inflammatory neuropathies varying between acute and chronic subtypes. Composite scores constructed from multi-dimensional CSF parameters establish potential novel diagnostic tools. Intra-disease heterogeneity suggests distinct disease mechanisms in subgroups of inflammatory neuropathies.

Sulfatides ameliorate experimental autoimmune neuritis by suppressing Th1/Th17 cells

Sulfatides have immunomodulatory functions, and play protective roles in multiple autoimmune diseases. In the present study, we showed that sulfatides ameliorated experimental autoimmune neuritis in Lewis rats induced with bovine peripheral myelin, which was associated with decreased proportions of Th1 and Th17 cells. Furthermore, compared control group, cells from sulfatide-treated rats exhibited lower potential in proliferation and IL-17 secretion in the presence of BPM or ConA in vitro. Moreover, sulfatides also reduced the proportions of NK and NKT cells. In summary, our study indicated that sulfatides might become a new therapeutic agent in Guillain-Barré syndrome in the future.

Expression and significance of interleukin-17 and interleukin-22 in the serum and the lower esophageal sphincter of patients with achalasia

Background/Aim

: We studied the expression of interleukin-17 and interleukin-22 in the serum and the lower esophageal sphincter (LES) in healthy individuals and in patients diagnosed with achalasia (AC) to gain a better understanding of the etiopathogenesis of AC.

Patients and Methods

Our study comprised 14 randomly selected patients with AC who underwent peroral endoscopic myotomy and 14 randomly selected healthy individuals who served as controls. Venous blood samples were evaluated in all study subjects to detect the expression of interleukin-17 and interleukin-22 in the serum using an enzyme-linked immunosorbent assay. Immunohistochemistry studies were performed to evaluate LES myofilaments obtained from both groups, as well as from 12 patients diagnosed with a subendothelial non-invasive tumor and who had undergone submucosal tunneling endoscopic resection, to assess the expression of interleukin-17 and interleukin-22 in LES myofilaments.

Results

Compared with that in the control group, the expression of interleukin-17 and interleukin-22 in the serum and LES, in patients with AC, was significantly increased and was positively correlated.

Conclusion

Interleukin-17 and interleukin-22 are upregulated in the serum and LES in patients with AC, suggesting that both interleukin-17 and interleukin-22 are involved in the pathogenesis of AC, and that AC may be an immune-mediated inflammatory disease.

Comprehensive cytokine profiling provides evidence for a multi-lineage Th responses in Guillain Barré Syndrome

Guillain Barré Syndrome (GBS) is one of the commonest acquired immune-mediated neuropathies, often preceded by infections. Although cellular immune responses are shown to substantially account for the pathophysiology of GBS, the precise mechanistic basis of risk and disease course remains enigmatic till date. Cytokines are best known for their abilities to drive cellular immunity and inflammation through their co-ordinated actions. Data obtained from clinical and animal model studies suggest important implications of some of the cytokines in the progression and recovery of GBS. However, these studies were performed on few cytokines and small set of GBS patients, thereby lacking a complete understanding of the patterns of association of cytokines representing Th1, Th2, and Th17 responses with GBS. We studied 65 well-characterized GBS patients and 73 age- and sex-matched healthy controls. A panel of 15 cytokines representing Th1, Th2 and Th17 pathways was assayed using Multiplex Suspension Array platform. Plasma levels of five cytokines were found to be altered in GBS patients compared to healthy control subjects: (i) IL-1β exhibited reduced levels, and (ii) IFN-γ, IL-4, IL-21 and IL-33 were elevated in GBS patients. The most important finding of this study was up-regulated expression of IL-21 and IL-33 in patients with GBS. Given the role of IL-33 as an alarmin, the elevated level of this cytokine provides important indication about a much broader role of cytokines in GBS. This study also provides evidence towards a multi-lineage Th cells (Th1, Th2 and Th17) associated cytokine responses in the pathophysiology of GBS.

Advances in Biomarker-Guided Therapy for Pediatric- and Adult-Onset Neuroinflammatory Disorders: Targeting Chemokines/Cytokines

The concept and recognized components of “neuroinflammation” are expanding at the intersection of neurobiology and immunobiology. Chemokines (CKs), no longer merely necessary for immune cell trafficking and positioning, have multiple physiologic, developmental, and modulatory functionalities in the central nervous system (CNS) through neuron–glia interactions and other mechanisms affecting neurotransmission. They issue the “help me” cry of neurons and astrocytes in response to CNS injury, engaging invading lymphoid cells (T cells and B cells) and myeloid cells (dendritic cells, monocytes, and neutrophils) (adaptive immunity), as well as microglia and macrophages (innate immunity), in a cascade of events, some beneficial (reparative), others destructive (excitotoxic). Human cerebrospinal fluid (CSF) studies have been instrumental in revealing soluble immunobiomarkers involved in immune dysregulation, their dichotomous effects, and the cells—often subtype specific—that produce them. CKs/cytokines continue to be attractive targets for the pharmaceutical industry with varying therapeutic success. This review summarizes the developing armamentarium, complexities of not compromising surveillance/physiologic functions, and insights on applicable strategies for neuroinflammatory disorders. The main approach has been using a designer monoclonal antibody to bind directly to the chemo/cytokine. Another approach is soluble receptors to bind the chemo/cytokine molecule (receptor ligand). Recombinant fusion proteins combine a key component of the receptor with IgG1. An additional approach is small molecule antagonists (protein therapeutics, binding proteins, and protein antagonists). CK neutralizing molecules (“neutraligands”) that are not receptor antagonists, high-affinity neuroligands (“decoy molecules”), as well as neutralizing “nanobodies” (single-domain camelid antibody fragment) are being developed. Simultaneous, more precise targeting of more than one cytokine is possible using bispecific agents (fusion antibodies). It is also possible to inhibit part of a signaling cascade to spare protective cytokine effects. “Fusokines” (fusion of two cytokines or a cytokine and CK) allow greater synergistic bioactivity than individual cytokines. Another promising approach is experimental targeting of the NLRP3 inflammasome, amply expressed in the CNS and a key contributor to neuroinflammation. Serendipitous discovery is not to be discounted. Filling in knowledge gaps between pediatric- and adult-onset neuroinflammation by systematic collection of CSF data on CKs/cytokines in temporal and clinical contexts and incorporating immunobiomarkers in clinical trials is a challenge hereby set forth for clinicians and researchers.

Novel pathomechanisms in inflammatory neuropathies

Inflammatory neuropathies are rare autoimmune-mediated disorders affecting the peripheral nervous system. Considerable progress has recently been made in understanding pathomechanisms of these disorders which will be essential for developing novel diagnostic and therapeutic strategies in the future. Here, we summarize our current understanding of antigenic targets and the relevance of new immunological concepts for inflammatory neuropathies. In addition, we provide an overview of available animal models of acute and chronic variants and how new diagnostic tools such as magnetic resonance imaging and novel therapeutic candidates will benefit patients with inflammatory neuropathies in the future. This review thus illustrates the gap between pre-clinical and clinical findings and aims to outline future directions of development.

IL-22 Impedes the Proliferation of Schwann cells: Transcriptome Sequencing and Bioinformatics Analysis

Schwann cells (SCs) proliferation is crucial for nerve regeneration following nerve injury. This study aims to investigate effects of interleukin-22 (IL-22) on SCs proliferation in vitro, as well as the corresponding mechanism. Rat SCs were treated with 100 ng/ml rat IL-22 for 48 h, and cell proliferation and apoptosis were detected using fluorescent staining and flow cytometry. After transcriptome sequencing, raw reads were filtered and mapped to reference genome rn5. Then, differentially expressed genes (DEGs) and long non-coding RNAs (DElncRNAs) between IL-22 and control groups were identified (tool: Cuffdiff). Functional and pathway enrichment analyses were performed (tool: GOFunction), and protein-protein interaction (PPI) network was constructed (tool: STRING and Cytoscape). Furthermore, Pearson's correlations between DEGs and DElncRNAs were analyzed, and regulatory network of DEGs, DElncRNAs, and transcription factors (TFs) was constructed. IL-22 significantly inhibited proliferation (p value < 0.05) and promoted apoptosis of Schwann cells. Totally, 932 DEGs and 118 DElncRNAs were identified, among which Ccl2 and Ccna2 were hub genes in PPI network. Up-regulated DEGs were enriched in apoptosis related terms, whereas down-regulated DEGs were enriched in proliferation related terms. DElncRNAs like NONRATT023505, NONRATG020400, and NONRATT022748 were correlated with multiple DEGs enriched in cell cycle and division. Moreover, up-regulated TFs Egr1, Cebpd, and Atf4 play crucial roles in regulatory network, and NONRATG020400-Cebpd-Ccl2, NONRATT023505/NONRATT022748-Atf4-Ccna2, and NONRATT022748-Egr1-Id1/Aldoc/Eno2/F3/Serpine1 regulatory pathways were identified in SCs after IL-22 treatment. IL-22 might influence SCs proliferation and apoptosis via regulating lncRNA-TF-gene pathways in SCs. However, more studies are required to confirm these results.

Pathological analysis of children with childhood central nervous system infection based on changes in chemokines and interleukin-17 family cytokines in cerebrospinal fluid

BACKGROUND

In this study, the pathologies of acute meningitis and encephalopathy were investigated, and biomarkers useful as prognostic indices were searched for.

METHODS

The subjects were 31 children with meningitis, 30 with encephalopathy, and 12 with convulsions following gastroenteritis. Control group consisted of 24 children with non-central nervous system infection. Cerebrospinal fluid cytokine analysis was performed.

RESULTS

Chemokines significantly increased in the bacterial meningitis group compared with those in viral meningitis and encephalopathy groups. On comparison of interleukin(IL)-17, it increased in cases with status epilepticus in influenza-associated encephalopathy group. In the rotavirus encephalopathy and convulsions following gastroenteritis groups, IL-17 particularly increased in the convulsions following gastroenteritis group. IL-8 increased in all cases irrespective of the causative virus.

CONCLUSIONS

In the encephalopathy group, IL-8 may serve as a neurological prognostic index. IL-17 was increased in the convulsions following gastroenteritis group, particularly in cases with status epilepticus, suggesting its involvement as a convulsion-related factor.

IL-22, GM-CSF and IL-17 in peripheral CD4+ T cell subpopulations during multiple sclerosis relapses and remission. Impact of corticosteroid therapy

Multiple sclerosis (MS) is thought to be a Th17-mediated dysimmune disease of the central nervous system. However, recent publications have questioned the pathogenicity of IL-17 per se and rather suggest the implication of other Th17-related inflammatory mediators. Therefore, we studied the expression of GM-CSF, IL-22, IL-24, IL-26 and CD39 in peripheral blood mononuclear cells (PBMCs) from MS patients during relapses, remission and following corticosteroid treatment. We performed qPCR to measure mRNA levels from ex vivo or in vitro-stimulated PBMCs. Cytokine levels were determined by ELISA. We used flow cytometry to assess GM-CSF+, IL-22+ and CD39+ cells in relationship to IL-17+ CD4+ T cells. Our results showed that IL-22 mRNA and IL-22+CD4+ lymphocytes are increased in circulating cells of relapsing MS patients compared to remitting patients while GM-CSF was unchanged. We have further shown that 12.9, 39 and 12.4% of Th17 cells from MS patients during relapses expressed IL-22, GM-CSF and CD39 respectively. No changes in these proportions were found in stable MS patients. However, the majority of GM-CSF+ or IL-22+ T cells did not co-express IL-17. GM-CSF mRNA, but not IL-22 mRNA, was dramatically decreased ex vivo by ivMP. Our results contribute to a better characterisation of Th17, Th22 and ThGM-CSF cells in the setting of MS and according to disease activity.

A Functional IL22 Polymorphism (rs2227473) Is Associated with Predisposition to Childhood Cerebral Malaria

Cerebral malaria (CM) is a severe complication of Plasmodium falciparum infection. This encephalopathy is characterized by coma and is thought to result from mechanical microvessel obstruction and an excessive activation of immune cells leading to pathological inflammation and blood-brain barrier alterations. IL-22 contributes to both chronic inflammatory and infectious diseases, and may have protective or pathogenic effects, depending on the tissue and disease state. We evaluated whether polymorphisms (n = 46) of IL22 and IL22RA2 were associated with CM in children from Nigeria and Mali. Two SNPs of IL22, rs1012356 (P = 0.016, OR = 2.12) and rs2227476 (P = 0.007, OR = 2.08) were independently associated with CM in a sample of 115 Nigerian children with CM and 160 controls. The association with rs2227476 (P = 0.01) was replicated in 240 nuclear families with one affected child from Mali. SNP rs2227473, in linkage disequilibrium with rs2227476, was also associated with CM in the combined cohort for these two populations, (P = 0.004, OR = 1.55). SNP rs2227473 is located within a putative binding site for the aryl hydrocarbon receptor, a master regulator of IL-22 production. Individuals carrying the aggravating T allele of rs2227473 produced significantly more IL-22 than those without this allele. Overall, these findings suggest that IL-22 is involved in the pathogenesis of CM.

Quantitative proteomics reveals Piccolo as a candidate serological correlate of recovery from Guillain-Barré syndrome

Guillain-Barré syndrome (GBS) is an autoimmune-mediated peripheral neuropathy of unknown cause. However, about a quarter of GBS patients have suffered a recent bacterial or viral infection, and axonal forms of the disease are especially common in these patients. Proteomics is a good methodological approach for the discovery of disease biomarkers. Until recently, most proteomics studies of GBS and other neurodegenerative diseases have focused on the analysis of the cerebrospinal fluid (CSF). However, serum represents an attractive alternative to CSF because it is easier to sample and has potential for biomarker discovery. The goal of this research was the identification of serum biomarkers associated with recovery from GBS. To address this objective, a quantitative proteomics approach was used to characterize differences in the serum proteome between a GBS patient and her healthy identical twin in order to lessen variations due to differences in genetic background, and with additional serum samples collected from unrelated GBS (N = 3) and Spinal Cord Injury (SCI) (N = 3) patients with similar medications. Proteomics results were then validated by ELISA using sera from additional GBS patients (N = 5) and healthy individuals (N = 3). All GBS and SCI patients were recovering from the acute phase of the disease. The results showed that Piccolo, a protein that is essential in the maintenance of active zone structure, constitutes a potential serological correlate of recovery from GBS. These results provided the first evidence for the Piccolo´s putative role in GBS, suggesting a candidate target for developing a serological marker of disease recovery.

Circulating memory T follicular helper subsets, Tfh2 and Tfh17, participate in the pathogenesis of Guillain-Barré syndrome

Circulating memory T follicular helper subsets, Tfh2 and Tfh17 are found to be aberrantly regulated in many autoimmune diseases. However, their roles in the pathogenesis of GBS are still unclear. This study examined the phenotype, distribution, clinical relevance and potential function of Tfh2 and Tfh17 in 36 GBS patients (including 24 AMAN and 12 AIDP patients). We found that the absolute counts of total memory Tfh cells were significantly increased in AMAN, while no significant difference in AIDP compared with HC. Furthermore, the levels of the three subsets of memory Tfh cells, Tfh1, Tfh2 and Tfh17, were differentially altered in AMAN. The absolute counts of Tfh1, Tfh2 and Tfh17 were all increased to a higher level in AMAN. The ratio of (Tfh2+Tfh17)/Tfh1 and the percentages of ICOS⁺ cells in Tfh2 and Tfh17 cells were greater in AMAN when compared to AIDP and HC, and the former had a positive correlation with the severity of both AMAN and AIDP. Conversely, the percentages of PD1⁺ cells in Tfh2 and Tfh17 cells were lower in AMAN than in HC. Therefore, circulating memory Tfh2 and Tfh17 cells might promote the autoantibody-related immune response and serve as useful markers to evaluate the progression of AMAN.

Exploring the role of interleukin-22 in neurological and autoimmune disorders

Interleukin-22 (IL-22) is a member of the IL-10 cytokine family that has recently gained attention in regard to its recognized pathogenic role in neurological and autoimmune disorders. The pathological involvement of IL-22 has been linked to Th17 cells that are involved in its production. Its biological activity results from its ability to bind to a heterodimeric receptor consisting of IL-22 receptor 1 (IL-22R1) and IL-10R2. Emerging evidence has identified IL-22 involvement in neurological diseases and autoimmune disorders such as Guillain-Barré Syndrome (GBS), multiple sclerosis (MS), Alzheimer's disease (AD), encephalitis, inflammatory myopathies, myasthenia gravis (MG), systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), Sjogren's syndrome (SS), psoriasis and Crohn's disease (CD). However, the biological activity of IL-22 is variable resulting in protective or pathogenic effects in different disease states. As such, the development of therapeutic targeting strategies to modify the biological activity of IL-22 is being explored as a promising interventional approach to treat neurological and autoimmune diseases.

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.

CCL27: Novel Cytokine with Potential Role in Pathogenesis of Multiple Sclerosis

Multiple sclerosis (MS) is an autoimmune and neurodegenerative disease of unknown etiology. Leukocyte infiltration of brain tissue and the subsequent inflammation, demyelination, axonal damage, and formation of sclerotic plaques is a hallmark of MS. Upregulation of proinflammatory cytokines has been suggested to play an essential role in regulating lymphocyte migration in MS. Here we present data on serum cytokine expression in MS cases. Increased serum levels of IL-17 and IL-23 were observed, suggesting activation of the Th17 population of immune effector cells. Additionally, increased levels of IL-22 were observed in the serum of those with acute phase MS. Unexpectedly, we observed an upregulation of the serum chemokine CCL27 in newly diagnosed and acute MS cases. CCL27 is an inflammatory chemokine associated with homing of memory T cells to sites of inflammation. Therefore, its upregulation in association with MS suggests a potential role in disease pathogenesis. Our data supports previous reports showing IL-17 and -23 upregulation in association with MS and potentially identify a previously unknown involvement for CCL27.

Impact of cytokine in type 1 narcolepsy: Role of pandemic H1N1 vaccination ?

Recent advances in the identification of susceptibility genes and environmental exposures (pandemic influenza 2009 vaccination) provide strong support that narcolepsy type 1 is an immune-mediated disease. Considering the limited knowledge regarding the immune mechanisms involved in narcolepsy whether related to flu vaccination or not and the recent progresses in cytokine measurement technology, we assessed 30 cytokines, chemokines and growth factors using the Luminex technology in either peripheral (serum) or central (CSF) compartments in a large population of 90 children and adult patients with narcolepsy type 1 in comparison to 58 non-hypocretin deficient hypersomniacs and 41 healthy controls. Furthermore, we compared their levels in patients with narcolepsy whether exposed to pandemic flu vaccine or not, and analyzed the effect of age, duration of disease and symptom severity. Comparison for sera biomarkers between narcolepsy (n = 84, 54 males, median age: 15.5 years old) and healthy controls (n = 41, 13 males, median age: 20 years old) revealed an increased stimulation of the immune system with high release of several pro- and anti-inflammatory serum cytokines and growth factors with interferon-γ, CCL11, epidermal growth factor, and interleukin-2 receptor being independently associated with narcolepsy. Increased levels of interferon-γ, CCL11, and interleukin-12 were found when close to narcolepsy onset. After several adjustments, only one CSF biomarker differed between narcolepsy (n = 44, 26 males, median age: 15 years old) and non-hypocretin deficient hypersomnias (n = 57, 24 males, median age: 36 years old) with higher CCL 3 levels found in narcolepsy. Comparison for sera biomarkers between patients with narcolepsy who developed the disease post-pandemic flu vaccination (n = 36) to those without vaccination (n = 48) revealed an increased stimulation of the immune system with high release of three cytokines, regulated upon activation normal T-cell expressed and secreted, CXCL10, and CXCL9, being independently and significantly increased in the group exposed to the vaccine. No significant differences were found between narcoleptics whether exposed to flu vaccination or not for CSF biomarkers except for a lower CXCL10 level found in the exposed group. To conclude, we highlighted the role of sera cytokine with pro-inflammatory properties and especially interferon-γ being independently associated with narcolepsy close to disease onset. The activity of the interferon-γ network was also increased in the context of narcolepsy after the pandemic flu vaccination being a potential key player in the immune mechanism that triggers narcolepsy and that coordinates the immune response necessary for resolving vaccination assaults.

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.

Role of cytokines and Toll-like receptors in the immunopathogenesis of Guillain-Barré syndrome

Guillain-Barré syndrome (GBS) is an autoimmune disease of the peripheral nervous system, mostly triggered by an aberrant immune response to an infectious pathogen. Although several infections have been implicated in the pathogenesis of GBS, not all such infected individuals develop this disease. Moreover, infection with a single agent might also lead to different subtypes of GBS emphasizing the role of host factors in the development of GBS. The host factors regulate a broad range of inflammatory processes that are involved in the pathogenesis of autoimmune diseases including GBS. Evidences suggest that systemically and locally released cytokines and their involvement in immune-mediated demyelination and axonal damage of peripheral nerves are important in the pathogenesis of GBS. Toll-like receptors (TLRs) link innate and adaptive immunity through transcription of several proinflammatory cytokines. TLR genes may increase susceptibility to microbial infections; an attenuated immune response towards antigen and downregulation of cytokines occurs due to mutation in the gene. Herein, we discuss the crucial role of host factors such as cytokines and TLRs that activate the immune response and are involved in the pathogenesis of the disease.

Mitigated Tregs and augmented Th17 cells and cytokines are associated with severity of experimental autoimmune neuritis

Experimental autoimmune neuritis (EAN), an animal model of human Guillain-Barré syndrome, has long been considered as a T helper (Th) 1 cell-mediated autoimmune disorder. However, deficiency of IFN-γ, a signature Th1 cytokine, aggravated EAN, with features of elevated production of IL-17A, despite an alleviated systemic Th1 immune response. We hypothesized that Th17 cells and their cytokines might play a pathogenic role in EAN. To further clarify the roles of these Th and regulatory T cell (Treg) cytokines in the pathogenesis of EAN and their interrelationship, we investigated the expression of Th1/Th2/Th17/Treg cytokines in EAN in this study. We found that the levels of Th17 cells and IL-17A in cauda equina (CE)-infiltrating cells and splenic mononuclear cells (MNCs) as well as in serum paralleled the disease evolution, which increased progressively during the initiation stage and reached higher value at the peak of EAN. The same pattern was also noticed for the expression of IL-22. The diverse expression profiles of FoxP3, IL-17 receptors A and C were seen in CE-infiltrating cells and splenic MNCs in EAN. These findings indicate a major pro-inflammatory role of Th17 cells and IL-17A in the pathogenesis of EAN. Therapeutic interventions may be focused upon inhibiting Th17 cells and their cytokines in the early phase of EAN, so as to delay and suppress clinical signs of the disease, which has relevance for future studies on pathogenesis and treatment of GBS in humans.

Interleukin-17 impedes Schwann cell-mediated myelination

Background

Pro-inflammatory cytokines are known to have deleterious effects on Schwann cells (SCs). Interleukin 17 (IL-17) is a potent pro-inflammatory cytokine that exhibits relevant effects during inflammation in the peripheral nervous system (PNS), and IL-17-secreting cells have been reported within the endoneurium in proximity to the SCs.

Methods

Here, we analyzed the effects of IL-17 on myelination and the immunological properties of SCs. Dorsal root ganglia (DRG) co-cultures containing neurons and SCs from BL6 mice were used to define the impact of IL-17 on myelination and on SC differentiation; primary SCs were analyzed for RNA and protein expression to define the putative immunological alignment of the SCs.

Results

SCs were found to functionally express the IL-17 receptors A and B. In DRG cultures, stimulation with IL-17 resulted in reduced myelin synthesis, while pro-myelin gene expression was suppressed at the mRNA level. Neuronal outgrowth and SC viability, as well as structural myelin formation, remained unaffected. Co-cultures exhibited SC-relevant pro-inflammatory markers, such as matrix metalloproteinase 9 and SCs significantly increased the expression of the major histocompatibility complex (MHC) I and exhibited a slight, nonsignificant increase in expression of MHCII, and a transporter associated with antigen presentation (TAP) II molecules relevant for antigen processing and presentation.

Conclusions

IL-17 may act as a myelin-suppressive mediator in the peripheral nerve, directly propagating SC-mediated demyelination, paralleled by an inflammatory alignment of the SCs. Further analyses are warranted to elucidate the role of IL-17 during inflammation in the PNS in vivo, which could be useful in the development of target therapies.