BAFF Index and CXCL13 levels in the cerebrospinal fluid associate respectively with intrathecal IgG synthesis and cortical atrophy in multiple sclerosis at clinical onset

Blood-brain barrier damage associates with glia-related cytokines in the cerebrospinal fluid of patients with Multiple Sclerosis

BACKGROUND

The presence of Blood-Brain Barrier (BBB) dysfunction is defined by albumin quotient (QALB) and characterize a group of Multiple Sclerosis (MS) patients at clinical onset. We evaluated the concentration in cerebrospinal fluid (CSF) of 87 cytokines, to better characterize the CSF inflammatory pattern in presence of BBB damage.

MATERIALS AND METHOD

In an exploratory cohort, CSF cytokines were evaluated by means of Multiplex technology (Bio-Plex Pro-Human Cytokine, GF and Diabetes 27-Plex Panel, Bio-Plex Pro-Human Chemokines 40-Plex Panel, Bio-Plex Pro-Human Inflammation Assays 37-Plex Panel) in a cohort of Other Not Inflammatory Neurological Disorders (ONIND) and in cohort of patients with MS, stratified according to BBB damage into QALB+ and QALB- MS patients. In the validation cohort, we evaluated the relevant molecules in a cohort of MS patients, stratified again into QALB+ and QALB-, including also Neurofilament Light (NfL) and Chitinase 3-like 1 (CHI3L1) CSF concentration.

RESULTS

While MIP-1α, CXCL-13, and CCL-22 CSF concentrations were higher in both MS groups compared to ONIND, in QALB+ MS CSF concentrations of CXCL-9 (17.85 ± 4.69 pg/mL), CXCL-10 (476.5 ± 324.3 pg/mL), and IL-16 (96.08 ± 86.17 pg/mL) were higher than in QALB- MS (8.98 ± 5368 pg/mL, p < 0.005, 281.0 ± 180.9 pg/mL, p < 0.05, and 47.35 ± 36.87 pg/mL, p < 0.005, respectively) and ONIND (8.98 ± 5368 pg/mlL, p < 0.005, 281.0 ± 180.9 pg/mL, p < 0.005, and 47.35 ± 36.87 pg/mL, p < 0.001, respectively). A strong correlation was observed between CXCL-9 and CXCL-10 in all MS groups (all r>0.75, all p < 0.001). In the validation cohort again CXCL-10 CSF concentration were higher in QALB+ MS than in QALB- MS (94.25 ± 64.75 vs 153.8 ± 99.52, p < 0.05), while no difference was observed in serum. CSF NfL (1642 ± 1963 vs 3231 ± 3492 pg/mL, p < 0.05) and CHI3L1 (183.9 ± 86.62 vs 262 ± 137.5 ng/mL, p < 0.05) were increased in QALB+ MS.

CONCLUSIONS

BBB damage in MS is linked to a specific CSF cytokines pattern (CXCL-9, CXCL-10, IL-16), that are also involved in astrocyte-microglia interaction. To what extent their continuous production in the CNS may mark a more severe disease course merits to be investigated.

B cell activating factor levels are linked to distinct B cell markers in multiple sclerosis and following B cell depletion and repopulation

Recent studies have highlighted the important role of B cells in the pathogenesis of multiple sclerosis (MS). B cell activating factor (BAFF) and A proliferation inducing ligand (APRIL) play a major role in B cell survival and homeostasis. Here, we studied the association of BAFF and APRIL with B cell immune markers in MS and following B cell depletion and repopulation. We found that BAFF but not APRIL was significantly higher in plasma in untreated MS compared to controls. BAFF increased after rituximab treatment and decreased again during repopulation displaying an inverse correlation with B cell numbers, and more specifically switched memory B cell numbers. Cerebrospinal fluid BAFF inversely correlated with IgG index. BAFF displayed an inverse association to anti-EBV-CA antibodies. In summary, our study identified immune cells and factors that might regulate or be regulated by BAFF and APRIL levels in MS, and during B cell depletion and repopulation.

Bruton tyrosine kinase inhibitors: can they be optimized for the treatment of neuroinflammatory disorders?

INTRODUCTION

Bruton's tyrosine kinase (BTK) is a multifaceted player of the immune system which has been involved in the survival of hematological malignancies but also in the pathogenesis of immune-mediated diseases. Oral BTK inhibitors (BTKi) have become a cornerstone for the treatment of patients with B-cell malignancies, and are under investigation for several immune-mediated diseases.

AREAS COVERED

We reviewed the biology of BTK and emerging data on BTKi in patients with neuroinflammatory disorders of both the peripheral and central nervous system.

EXPERT OPINION

We support the use of BTKi in relapsed/refractory patients with multiple sclerosis and anti-MAG antibody neuropathies. However, other immune-mediated neuroinflammatory disorders are likely to benefit from BTKi. Whether BTKi will improve the response rates than conventional therapies in previously untreated patients is unknown and will be assessed within future clinical trials. Furthermore, the availability of more selective BTKi, with less adverse events, will improve patients' tolerability and expand our treatment landscape.

Bruton tyrosine kinase inhibitors for multiple sclerosis

Current therapies for multiple sclerosis (MS) reduce both relapses and relapse-associated worsening of disability, which is assumed to be mainly associated with transient infiltration of peripheral immune cells into the central nervous system (CNS). However, approved therapies are less effective at slowing disability accumulation in patients with MS, in part owing to their lack of relevant effects on CNS-compartmentalized inflammation, which has been proposed to drive disability. Bruton tyrosine kinase (BTK) is an intracellular signalling molecule involved in the regulation of maturation, survival, migration and activation of B cells and microglia. As CNS-compartmentalized B cells and microglia are considered central to the immunopathogenesis of progressive MS, treatment with CNS-penetrant BTK inhibitors might curtail disease progression by targeting immune cells on both sides of the blood-brain barrier. Five BTK inhibitors that differ in selectivity, strength of inhibition, binding mechanisms and ability to modulate immune cells within the CNS are currently under investigation in clinical trials as a treatment for MS. This Review describes the role of BTK in various immune cells implicated in MS, provides an overview of preclinical data on BTK inhibitors and discusses the (largely preliminary) data from clinical trials.

Protein biomarkers in multiple sclerosis

This review aimed to elucidate protein biomarkers in body fluids, such as blood and cerebrospinal fluid (CSF), to identify those that may be used for early diagnosis of multiple sclerosis (MS), prediction of disease activity, and monitoring of treatment response among MS patients. The potential biomarkers elucidated in this review include neurofilament proteins (NFs), glial fibrillary acidic protein (GFAP), leptin, brain-derived neurotrophic factor (BDNF), chitinase-3-like protein 1 (CHI3L1), C-X-C motif chemokine 13 (CXCL13), and osteopontin (OPN), with each biomarker playing a different role in MS. GFAP, leptin, and CHI3L1 levels were increased in MS patient groups compared to the control group. NFs are the most studied proteins in the MS field, and significant correlations with disease activity, future progression, and treatment outcomes are evident. GFAP CSF level shows a different pattern by MS subtype. Increased concentration of CHI3L1 in the blood/CSF of clinically isolated syndrome (CIS) is an independent predictive factor of conversion to definite MS. BDNF may be affected by chronic progression of MS. CHI3L1 has potential as a biomarker for early diagnosis of MS and prediction of disability progression, while CXCL13 has potential as a biomarker of prognosis of CIS and reflects MS disease activity. OPN was an indicator of disease severity. A periodic detailed patient evaluation should be performed for MS patients, and broadly and easily accessible biomarkers with higher sensitivity and specificity in clinical settings should be identified.

High levels of kappa free light chain synthesis predict cognitive decline in relapsing-remitting multiple sclerosis

Background

Evolving evidence suggests that measurement of cerebrospinal fluid (CSF) kappa free light chain (KFLC) synthesis has high diagnostic sensitivity and specificity for multiple sclerosis (MS), but its prognostic ability is less investigated. The usefulness of KFLC in predicting cognitive impairment (CI) is still unknown.

Methods

In a monocentric longitudinal retrospecitve cohort study, KFLC-index ([CSF KFLC/serum KFLC]/[CSF albumin/serum albumin]) measured by latex-enhanced immunonephelometry was prospectively determined as part of the diagnostic workup in patients with early relapsing-remitting MS (RRMS, n=77). The ability of KFLC-index to predict information processing speed (IPS) worsening as assessed with the symbol digit modalities test (SDMT) was investigated in univariable and multivariable models.

Results

In patients with KFLC-index>100 (n=31), 11 subjects (35.5%) showed reduced SDMT scores by ≥8 points at follow-up (mean follow-up time 7.3 ± 2.6 years), compared with their baseline scores (p=0.01). Baseline KFLC-index>100 was strongly associated with a higher hazard of SDMT score reduction at follow-up (adjusted hazard ratio 10.5, 95% confidence interval 2.2-50.8, p=0.003; median time to SDMT reduction 7 years).

Conclusion

Intrathecal KFLC synthesis has become an attractive diagnostic tool for MS. We show for the first time that in a real-world setting of early RRMS, KFLC-index predicted cognitive decline. Whether this predictive ability of KFLC-index also concerns other cognitive domains than IPS, warrants further investigations.

CSF CXCL13 and Chitinase 3-like-1 Levels Predict Disease Course in Relapsing Multiple Sclerosis

Several biomarkers from multiple sclerosis (MS) patients' biological fluids have been considered to support diagnosis, predict disease course, and evaluate treatment response. In this study, we assessed the CSF concentration of selected molecules implicated in the MS pathological process. To investigate the diagnostic and prognostic significance of CSF concentration of target candidate biomarkers in both relapsing (RMS, n = 107) and progressive (PMS, n = 18) MS patients and in other inflammatory (OIND, n = 10) and non-inflammatory (ONIND, n = 15) neurological disorders. We measured the CSF concentration of APRIL, BAFF, CHI3L1, CCL-2, CXCL-8, CXCL-10, CXCL-12, CXCL-13 through a Luminex Assay. MS patients were prospectively evaluated, and clinical and radiological activity were recorded. CHI3L1 and CXCL13 CSF levels were significantly higher in both MS groups compared to control groups, while CCL2, BAFF, and APRIL concentrations were lower in RMS patients compared to PMS and OIND. Considering RMS patients with a single demyelinating event, higher concentrations of CHI3L1, CXCL10, CXCL12, and CXCL13 were recorded in patients who converted to clinically defined MS(CDMS). RMS patients in the CXCL13 and CHI3L1 high concentration group had a significantly higher risk of relapse (HR 12.61 and 4.57), MRI activity (HR 7.04 and 2.46), and of any evidence of disease activity (HR 12.13 and 2.90) during follow-up. CSF CXCL13 and CHI3L1 levels represent very good prognostic biomarkers in RMS patients, and therefore can be helpful in the treatment choice. Higher CSF concentrations of neuro-inflammatory biomarkers were associated with a higher risk of conversion to CDMS in patients with a first clinical demyelinating event. Differential CSF BAFF and APRIL levels between RMS and PMS suggest a different modulation of B-cells pathways in the different phases of the disease.

Epstein-Barr virus infection, B-cell dysfunction and other risk factors converge in gut-associated lymphoid tissue to drive the immunopathogenesis of multiple sclerosis: a hypothesis

Multiple sclerosis is associated with Epstein-Barr virus (EBV) infection, B-cell dysfunction, gut dysbiosis, and environmental and genetic risk factors, including female sex. A disease model incorporating all these factors remains elusive. Here, we hypothesise that EBV-infected memory B cells (MBCs) migrate to gut-associated lymphoid tissue (GALT) through EBV-induced expression of LPAM-1, where they are subsequently activated by gut microbes and/or their products resulting in EBV reactivation and compartmentalised anti-EBV immune responses. These responses involve marginal zone (MZ) B cells that activate CD4⁺ T-cell responses, via HLA-DRB1, which promote downstream B-cell differentiation towards CD11c⁺/T-bet⁺ MBCs, as well as conventional MBCs. Intrinsic expression of low-affinity B-cell receptors (BCRs) by MZ B cells and CD11c⁺/T-bet⁺ MBCs promotes polyreactive BCR/antibody responses against EBV proteins (e.g. EBNA-1) that cross-react with central nervous system (CNS) autoantigens (e.g. GlialCAM). EBV protein/autoantigen-specific CD11c⁺/T-bet⁺ MBCs migrate to the meningeal immune system and CNS, facilitated by their expression of CXCR3, and induce cytotoxic CD8⁺ T-cell responses against CNS autoantigens amplified by BAFF, released from EBV-infected MBCs. An increased abundance of circulating IgA⁺ MBCs, observed in MS patients, might also reflect GALT-derived immune responses, including disease-enhancing IgA antibody responses against EBV and gut microbiota-specific regulatory IgA⁺ plasma cells. Female sex increases MZ B-cell and CD11c⁺/T-bet⁺ MBC activity while environmental risk factors affect gut dysbiosis. Thus, EBV infection, B-cell dysfunction and other risk factors converge in GALT to generate aberrant B-cell responses that drive pathogenic T-cell responses in the CNS.

Intrathecal B cell-related markers for an optimized biological investigation of multiple sclerosis patients

In multiple sclerosis (MS) disease, the importance of the intrathecal B cell response classically revealed as IgG oligoclonal bands (OCB) in cerebrospinal fluid (CSF) was reaffirmed again in the recently revised diagnostic criteria. We aimed to optimize Laboratory investigation by testing the performance of new B cell-related molecules in CSF (Ig free light chains (FLCκ and λ) and CXCL13 (B-Cell Attracting chemokine1)) for MS diagnosis. 320 paired (CSF-serum) samples were collected from 160 patients with MS (n = 82) and non-MS diseases (n = 78). All patients benefited from IgG index determination, OCB detection, CSF CXCL13 and FLC (κ and λ) measurement in CSF and serum for metrics calculation (κ/λ ratio, FLC-related indexes, and κFLC-intrathecal fraction (IF)). CXCL13 and FLC metrics in CSF were higher in patients with MS and positive OCB. As expected, κFLC metrics—in particular, κFLC index and κFLC IF—had the highest accuracy for MS diagnosis. κ index showed the best performance (sensitivity 83% and specificity 91.7%) at a cut-off of 14.9. Most of the FLC-related parameters were positively correlated with IgG index and the level of CXCL13. In conclusion, the quantitative, standardizable, and technically simple CSF FLCκ metrics seem to be reliable for MS diagnosis, but could not replace OCB detection. CXCL13 appears to be an effective parameter reflecting the intrathecal B cell response. An optimized way for CSF testing combining the conventional and the new B cell-related parameters is proposed in this study.

Hyper-Reflecting Foci in Multiple Sclerosis Retina Associate With Macrophage/Microglia-Derived Cytokines in Cerebrospinal Fluid

Background

Increasing evidence suggests that retinal hyper-reflecting foci (HRF) might be clusters of activated and proliferating microglia. Since microglia are widespread activated in multiple sclerosis (MS) brain, its evaluation in retina may help to understand and monitor MS-related pathology.

Aim

This study aims at investigating the association of HRF with cerebrospinal fluid (CSF) cytokines and MRI parameters in relapsing–remitting MS (RRMS).

Methods

Nineteen RRMS at clinical onset and 15 non-inflammatory neurological disorders (NIND) underwent brain 3T MRI and CSF examination. Optical coherence tomography (OCT) analysis, including HRF count, was performed on RRMS patients. Sixty-nine cytokines/chemokines were analyzed in the CSF by multiplex technology.

Results

In RRMS, HRF count in the ganglion cell layer (GCL) was associated with IL-1Ra, IL-9, IL-15, IFN-γ, and G-CSF. Moreover, in RRMS patients CSF concentrations of IL-1Ra and G-CSF associated with global cortical thickness. The HRF count in the inner nuclear layer (INL) correlated with IL-22, IL-34, IL-35, CXCL-2, CXCL-10, and CXCL-13, and multivariate analysis confirmed a strong association (r²: 0.47) with both CXCL-2 (β: -0.965, p = 0.0052) and CXCL-13 (β: 0.241, p = 0.018). This latter cytokine increased in RRMS with high HRF count compared with NIND and RRMS with low HRF count. Finally, the CXCL-13/CXCL-2 ratio strongly associated with HRF count (r: 0.8, p < 0.005) and cortical lesion volume (r: 0.5, p < 0.05).

Conclusions

The association of HRF with intrathecally produced monocyte/microglia-derived cytokines confirms their microglial origin and indicates they are worth further evaluating as markers of activated microglia.

CXCL13 expressed on inflamed cerebral blood vessels recruit IL-21 producing TFH cells to damage neurons following stroke

BACKGROUND

Ischemic stroke is a leading cause of mortality worldwide, largely due to the inflammatory response to brain ischemia during post-stroke reperfusion. Despite ongoing intensive research, there have not been any clinically approved drugs targeting the inflammatory component to stroke. Preclinical studies have identified T cells as pro-inflammatory mediators of ischemic brain damage, yet mechanisms that regulate the infiltration and phenotype of these cells are lacking. Further understanding of how T cells migrate to the ischemic brain and facilitate neuronal death during brain ischemia can reveal novel targets for post-stroke intervention.

METHODS

To identify the population of T cells that produce IL-21 and contribute to stroke, we performed transient middle cerebral artery occlusion (tMCAO) in mice and performed flow cytometry on brain tissue. We also utilized immunohistochemistry in both mouse and human brain sections to identify cell types and inflammatory mediators related to stroke-induced IL-21 signaling. To mechanistically demonstrate our findings, we employed pharmacological inhibitor anti-CXCL13 and performed histological analyses to evaluate its effects on brain infarct damage. Finally, to evaluate cellular mechanisms of stroke, we exposed mouse primary neurons to oxygen glucose deprivation (OGD) conditions with or without IL-21 and measured cell viability, caspase activity and JAK/STAT signaling.

RESULTS

Flow cytometry on brains from mice following tMCAO identified a novel population of cells IL-21 producing CXCR5+ CD4+ ICOS-1+ T follicular helper cells (TFH) in the ischemic brain early after injury. We observed augmented expression of CXCL13 on inflamed brain vascular cells and demonstrated that inhibition of CXCL13 protects mice from tMCAO by restricting the migration and influence of IL-21 producing TFH cells in the ischemic brain. We also illustrate that neurons express IL-21R in the peri-infarct regions of both mice and human stroke tissue in vivo. Lastly, we found that IL-21 acts on mouse primary ischemic neurons to activate the JAK/STAT pathway and induce caspase 3/7-mediated apoptosis in vitro.

CONCLUSION

These findings identify a novel mechanism for how pro-inflammatory T cells are recruited to the ischemic brain to propagate stroke damage and provide a potential new therapeutic target for stroke.

Evolution of Anti-B Cell Therapeutics in Autoimmune Neurological Diseases

B cells have an ever-increasing role in the etiopathology of a number of autoimmune neurological disorders, acting as antigen-presenting cells facilitating antibody production but also as sensors, coordinators, and regulators of the immune response. In particular, B cells can regulate the T cell activation process through their participation in antigen presentation, production of proinflammatory cytokines (bystander activation or suppression), and contribution to ectopic lymphoid aggregates. Such an important interplay between B and T cells makes therapeutic depletion of B cells an attractive treatment strategy. The last decade, anti-B cell therapies using monoclonal antibodies against B cell surface molecules have evolved into a rational approach for successfully treating autoimmune neurological disorders, even when T cells seem to be the main effector cells. The paper summarizes basic aspects of B cell biology, discusses the roles of B cells in neurological autoimmunities, and highlights how the currently available or under development anti-B cell therapeutics exert their action in the wide spectrum and immunologically diverse neurological disorders. The efficacy of the various anti-B cell therapies and practical issues on induction and maintenance therapy is specifically detailed for the treatment of patients with multiple sclerosis, neuromyelitis-spectrum disorders, autoimmune encephalitis and hyperexcitability CNS disorders, autoimmune neuropathies, myasthenia gravis, and inflammatory myopathies. The success of anti-B cell therapies in inducing long-term remission in IgG4 neuroautoimmunities is also highlighted pointing out potential biomarkers for follow-up infusions.

Emerging Biomarkers of Multiple Sclerosis in the Blood and the CSF: A Focus on Neurofilaments and Therapeutic Considerations

INTRODUCTION

Multiple Sclerosis (MS) is the most common immune-mediated chronic neurodegenerative disease of the central nervous system (CNS) affecting young people. This is due to the permanent disability, cognitive impairment, and the enormous detrimental impact MS can exert on a patient's health-related quality of life. It is of great importance to recognise it in time and commence adequate treatment at an early stage. The currently used disease-modifying therapies (DMT) aim to reduce disease activity and thus halt disability development, which in current clinical practice are monitored by clinical and imaging parameters but not by biomarkers found in blood and/or the cerebrospinal fluid (CSF). Both clinical and radiological measures routinely used to monitor disease activity lack information on the fundamental pathophysiological features and mechanisms of MS. Furthermore, they lag behind the disease process itself. By the time a clinical relapse becomes evident or a new lesion appears on the MRI scan, potentially irreversible damage has already occurred in the CNS. In recent years, several biomarkers that previously have been linked to other neurological and immunological diseases have received increased attention in MS. Additionally, other novel, potential biomarkers with prognostic and diagnostic properties have been detected in the CSF and blood of MS patients.

AREAS COVERED

In this review, we summarise the most up-to-date knowledge and research conducted on the already known and most promising new biomarker candidates found in the CSF and blood of MS patients.

DISCUSSION

the current diagnostic criteria of MS relies on three pillars: MRI imaging, clinical events, and the presence of oligoclonal bands in the CSF (which was reinstated into the diagnostic criteria by the most recent revision). Even though the most recent McDonald criteria made the diagnosis of MS faster than the prior iteration, it is still not an infallible diagnostic toolset, especially at the very early stage of the clinically isolated syndrome. Together with the gold standard MRI and clinical measures, ancillary blood and CSF biomarkers may not just improve diagnostic accuracy and speed but very well may become agents to monitor therapeutic efficacy and make even more personalised treatment in MS a reality in the near future. The major disadvantage of these biomarkers in the past has been the need to obtain CSF to measure them. However, the recent advances in extremely sensitive immunoassays made their measurement possible from peripheral blood even when present only in minuscule concentrations. This should mark the beginning of a new biomarker research and utilisation era in MS.

Novel contributors to B cell activation during inflammatory CNS demyelination; An oNGOing process

Over the past two decades, the development of targeted immunotherapeutics for relapsing-remitting multiple sclerosis has been successfully orchestrated through the efficacious modulation of neuroinflammatory outcomes demonstrated in the experimental autoimmune encephalomyelitis (EAE) model. In this model, the focus of developing immunomodulatory therapeutics has been demonstrated through their effectiveness in modifying the pro-inflammatory Th1 and Th17-dependent neuropathological outcomes of demyelination, oligodendrocytopathy and axonal dystrophy. However, recent successful preclinical and clinical trials have advocated for the significance of B cell-dependent immunopathogenic responses and has led to the development of novel biologicals that target specific B cell phenotypes. In this context, a new molecule, B-cell activating factor (BAFF), has emerged as a positive regulator of B cell survival and differentiation functioning through various signaling pathways and potentiating the activity of various receptor complexes through pleiotropic means. One possible cognate receptor for BAFF includes the Nogo receptor (NgR) and its homologs, previously established as potent inhibitors of axonal regeneration during central nervous system (CNS) injury and disease. In this review we provide current evidence for BAFF-dependent signaling through the NgR multimeric complex, elucidating their association within the CNS compartment and underlying the importance of these potential pathogenic molecular regulators as possible therapeutic targets to limit relapse rates and potentially MS progression.

The Correlation Among the Immunoglobulin G Synthesis Rate, IgG Index and Albumin Quotient in Guillain-Barré Syndrome and Chronic Inflammatory Demyelinating Polyradiculoneuropathy: A Retrospective Case–Control Study

Background: The immunoglobulin G synthesis rate (IgG SR) and immunoglobulin G (IgG) index are indicators of abnormal intrathecal humoural immune responses, and the albumin quotient (QALB) is an indicator used to evaluate the completeness of the blood-cerebrospinal fluid barrier (BCB). No systematic reports regarding differences in Guillain-Barré syndrome (GBS) and chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) are available. We assessed differences in the IgG SR, IgG index and QALB between GBS and CIDP patients in a Chinese cohort.

Methods: A total of 234 patients were retrospectively enrolled in this study, and 167 clinically confirmed GBS and CIDP patients were selected. Meanwhile, 67 non-GBS and non-CIDP patients requiring cerebrospinal fluid (CSF) examination were enrolled as the control group. The IgG SR, IgG index and QALB were calculated using formulas. The relevant clinical data were subjected to statistical analysis.

Results: Among the GBS and CIDP study groups and the control group, the QALB had the highest positive rate (80.00%) in the CIDP group (P < 0.01). The QALB stratification analysis showed that the ranges of 10 < QALB ≤ 30 were dominant in the GBS and CIDP groups, and the positive rate of CIDP was higher than that of GBS. Furthermore, a QALB ≤ 7 was dominant in the control group, and a QALB > 30 was dominant in the CIDP group. In receiver operating characteristic (ROC) curve analysis with the CIDP group as the trial group and the GBS group as the control group, the differences in the QALB were statistically significant (P < 0.01). To achieve a high specificity of 98~99%, the diagnostic cut-off value for the QALB was above 57.37 (sensitivity: 9.33%) or below 0.60 (sensitivity: 4.35%). Multivariate logistic regression analysis showed that the CIDP patients had a QALB higher than 57.37, and compared with that in the GBS patients, the difference in the QALB was statistically significant (P < 0.01).

Conclusion: QALB elevation was associated with CIDP, while QALB values above 57.37 or below 0.60 had high specificity in differentiating between GBS and CIDP. In CIDP, the BCB is generally moderately to severely damaged; in GBS, the BCB is generally moderately damaged.

The blood biomarkers puzzle - A review of protein biomarkers in neurodegenerative diseases

Neurodegenerative diseases are heterogeneous in their cause and clinical presentation making clinical assessment and disease monitoring challenging. Because of this, there is an urgent need for objective tools such as fluid biomarkers able to quantitate different aspects of the disease. In the last decade, technological improvements and awareness of the importance of biorepositories led to the discovery of an evolving number of fluid biomarkers covering the main characteristics of neurodegenerative diseases such as neurodegeneration, protein aggregates and inflammation. The ability to quantitate each aspect of the disease at a high definition enables a more precise stratification of the patients at inclusion in clinical trials, hence reducing the noise that may hamper the detection of therapeutical efficacy and allowing for smaller but likewise powered studies, which particularly improves the ability to start clinical trials for rare neurological diseases. Moreover, the use of fluid biomarkers has the potential to support a targeted therapeutical intervention, as it is now emerging for the treatment of amyloid-beta deposition in patients suffering from Alzheimer's disease. Here we review the knowledge that evolved from the measurement of fluid biomarker proteins in neurodegenerative conditions.

A comprehensive review on the role of chemokines in the pathogenesis of multiple sclerosis

Multiple sclerosis (MS) as a chronic inflammatory disorder of the central nervous system (CNS) is thought to be caused by the abnormal induction of immune responses. Chemokines as molecules that can engage leukocytes into the location of inflammation, actively participate in the pathogenesis of MS. Several members of this family of chemo attractants have been shown to be dysregulated in the peripheral blood, cerebrospinal fluid or CNS lesions of MS patients. Studies in animal models of MS particularly experimental autoimmune encephalomyelitis have indicated the critical roles of chemokines in the pathophysiology of MS. In the current review, we summarize the data regarding the role of CCL2, CCL3, CCL4, CCL11, CCL20, CXCL1, CXCL2, CXCL8, CXCL10, CXCL12 and CXCL13 in the pathogenesis of MS.

Regulation of neuroinflammation by B cells and plasma cells

The remarkable success of anti-CD20 B cell depletion therapies in reducing the burden of multiple sclerosis (MS) disease has prompted significant interest in how B cells contribute to neuroinflammation. Most focus has been on identifying pathogenic CD20⁺ B cells. However, an increasing number of studies have also identified regulatory functions of B lineage cells, particularly the production of IL-10, as being associated with disease remission in anti-CD20-treated MS patients. Moreover, IL-10-producing B cells have been linked to the attenuation of inflammation in experimental autoimmune encephalomyelitis (EAE), the animal model of MS. In addition to IL-10-producing B cells, antibody-producing plasma cells (PCs) have also been implicated in suppressing neuroinflammation. This review will examine regulatory roles for B cells and PCs in MS and EAE. In addition, we speculate on the involvement of regulatory PCs and the cytokine BAFF in the context of anti-CD20 treatment. Lastly, we explore how the microbiota could influence anti-inflammatory B cell behavior. A better understanding of the contributions of different B cell subsets to the regulation of neuroinflammation, and factors that impact the development, maintenance, and migration of such subsets, will be important for rationalizing next-generation B cell-directed therapies for the treatment of MS.

The BAFF / APRIL system as therapeutic target in multiple sclerosis

INTRODUCTION

The complex system of BAFF (B-cell-activating factor of the TNF family) and APRIL (A proliferation-inducing ligand) has been studied in animal models of autoimmune diseases such as those resembling human systemic lupus erythematosus and Sjogren's syndrome and multiple sclerosis (MS). Accumulating evidence suggests that BAFF and APRIL have a physiological role in B cell immunity regulation, however inappropriate production of these factors may represent a key event which disrupts immune tolerance which is associated with systemic autoimmune diseases.

AREAS COVERED

We provide an update on the latest studies of the BAFF/APRIL system in multiple sclerosis, as well as on related clinical trials.

EXPERT OPINION

Experimental and clinical evidence suggests that increased BAFF levels may interfere directly and indirectly with B cell immunity; this can lead to breakdown of immune tolerance, the production of autoantibodies and continuous local intracerebral inflammation and brain tissue destruction. A more comprehensive understanding of the cell/molecular mechanism immune reactions specifically regulated by BAFF/APRIL in MS would better elucidate the specific cell phenotype targeted by actual anti-BAFF/APRIL therapies; this may enable the identification of either specific biomarkers of MS subgroups that would benefit of anti-BAFF/APRIL treatments or new targets of MS-specific anti-BAFF/APRIL therapies.

Aggressive multiple sclerosis (1): Towards a definition of the phenotype

While the major phenotypes of multiple sclerosis (MS) and relapsing-remitting, primary and secondary progressive MS have been well characterized, a subgroup of patients with an active, aggressive disease course and rapid disability accumulation remains difficult to define and there is no consensus about their management and treatment. The current lack of an accepted definition and treatment guidelines for aggressive MS triggered a 2018 focused workshop of the European Committee for Treatment and Research in Multiple Sclerosis (ECTRIMS) on aggressive MS. The aim of the workshop was to discuss approaches on how to describe and define the disease phenotype and its treatments. Unfortunately, it was not possible to come to consensus on a definition because of unavailable data correlating severe disease with imaging and molecular biomarkers. However, the workshop highlighted the need for future research needed to define this disease subtype while also focusing on its treatment and management. Here, we review previous attempts to define aggressive MS and present characteristics that might, with additional research, eventually help characterize it. A companion paper summarizes data regarding treatment and management.

Wide Cytokine Analysis in Cerebrospinal Fluid at Diagnosis Identified CCL-3 as a Possible Prognostic Factor for Multiple Sclerosis

Background: Apart from IgG oligoclonal bands, no other biomarker has, to date, been validated for diagnostic and/or prognostic purposes in multiple sclerosis (MS). Aim: To investigate a wide panel of cytokines and chemokines in the cerebrospinal fluid (CSF) of relapsing-remitting MS (RRMS) patients and evaluate their association with clinical and magnetic resonance imaging (MRI) parameters, as well as their predictive clinical value. Methods: Fifty-one RRMS at clinical onset and 17 other not inflammatory neurological disorders (ONINDs) underwent brain MRI (including 3D-T1, 3D-FLAIR, and 3-DIR sequences) and CSF examination. Eighty-seven cytokines and chemokines were analyzed in CSF by Multiplex technology. Results: Compared to ONIND, CXCL-10, CXCL-11, CXCL-13, CCL-1, CCL-2, CCL-3, CCL-22, IL-16, and BAFF were significantly (p < 0.05) increased in RRMS CSF. However, only CCL-3 was associated with both MS diagnosis and IgGOB detection. Based on a 95%CI in ONIND (cut-off value: 0.798 pg/ml) and ROC analysis (cut-off value: 0.495 pg/ml), RRMS patients were stratified in CCL-3^high (>0.736 pg/mL), CCL-3^medium, and CCL-3^low (<0.495 pg/ml). Survival analysis disclosed a strong association between high CCL-3 values and disease reactivation (OR = 4.9, 95%CI: 1.8-13.3, p < 0.005) in the following 2 years. Conclusions: CCL-3 deserves further investigation as a candidate prognostic biomarker for RRMS.

Decoding intrathecal immunoglobulins and B cells in the CNS: their synthesis, function, and regulation

The discovery of an active lymphatic system in the meninges (dura mater) has opened up a wide range of possibilities for the role of CNS immunoglobulins in brain development in early fetal life or during infancy. The antibody-dependent and -independent functions of B cells in the immunopathogenesis of multiple sclerosis are not new to immunologists, yet their role in other neurodegenerative disorders such as Alzheimer's and Parkinson's disease is incompletely understood. Deep cervical lymph nodes have emerged as a candidate site for autosensitization against CNS antigens and have been shown to provide the right kind of milieu for the dynamic interaction of antigen-presenting cells, B cells, and T cells. The presence of different B cells in the lymph nodes and the production of natural autoantibodies by B-1 cells have definitely unlocked another piece of the puzzle. At a time when CD19 and CD20 monoclonal antibodies have shown remarkable results in ameliorating the relapse and progression of multiple sclerosis, it is imperative to dissect out the diversity in B cell populations inside the CNS to identify new targets to improve current treatment regimens for neurodegenerative diseases. This review highlights the origin, migration, function, and regulation of B cells and the production of intrathecal immunoglobulins considering the previous and current findings and taking into account the differences between a healthy state and the changes that occur during an inflammatory or autoimmune response.

Cerebrospinal Fluid Analysis in Multiple Sclerosis Diagnosis: An Update

Multiple sclerosis (MS) is an immune-mediated demyelinating disease of the central nervous system (CNS) with brain neurodegeneration. MS patients present heterogeneous clinical manifestations in which both genetic and environmental factors are involved. The diagnosis is very complex due to the high heterogeneity of the pathophysiology of the disease. The diagnostic criteria have been modified several times over the years. Basically, they include clinical symptoms, presence of typical lesions detected by magnetic resonance imaging (MRI), and laboratory findings. The analysis of cerebrospinal fluid (CSF) allows an evaluation of inflammatory processes circumscribed to the CNS and reflects changes in the immunological pattern due to the progression of the pathology, being fundamental in the diagnosis and monitoring of MS. The detection of the oligoclonal bands (OCBs) in both CSF and serum is recognized as the “gold standard” for laboratory diagnosis of MS, though presents analytical limitations. Indeed, current protocols for OCBs assay are time-consuming and require an operator-dependent interpretation. In recent years, the quantification of free light chain (FLC) in CSF has emerged to assist clinicians in the diagnosis of MS. This article reviews the current knowledge on CSF biomarkers used in the diagnosis of MS, in particular on the validated assays and on the alternative biomarkers of intrathecal synthesis.

Targeting Microglia and Macrophages: A Potential Treatment Strategy for Multiple Sclerosis

Multiple sclerosis (MS) is a chronic inflammatory neurodegenerative disease of the central nervous system (CNS). The early stage is characterized by relapses and the later stage, by progressive disability. Results from experimental and clinical investigations have demonstrated that microglia and macrophages play a key part in the disease course. These cells actively initiate immune infiltration and the demyelination cascade during the early phase of the disease; however, they promote remyelination and alleviate disease in later stages. This review aims to provide a comprehensive overview of the existing knowledge regarding the neuromodulatory function of macrophages and microglia in the healthy and injured CNS, and it discusses the feasibility of harnessing microglia and macrophage physiology to treat MS. The review encourages further investigations into macrophage-targeted therapy, as well as macrophage-based drug delivery, for realizing efficient treatment strategies for MS.

MRI phenotypes in MS: Longitudinal changes and miRNA signatures

Objective

To classify and immunologically characterize persons with MS based on brain lesions and atrophy and their associated microRNA profiles.

Methods

Cerebral T2-hyperintense lesion volume (T2LV) and brain parenchymal fraction (BPF) were quantified and used to define MRI phenotypes as follows: type I: low T2LV, low atrophy; type II: high T2LV, low atrophy; type III: low T2LV, high atrophy; type IV: high T2LV, high atrophy, in a large cross-sectional cohort (n = 1,088) and a subset with 5-year lngitudinal follow-up (n = 153). Serum miRNAs were assessed on a third MS cohort with 2-year MRI phenotype stability (n = 98).

Results

One-third of the patients had lesion-atrophy dissociation (types II or III) in both the cross-sectional and longitudinal cohorts. At 5 years, all phenotypes had progressive atrophy (p < 0.001), disproportionally in type II (BPF -2.28%). Only type IV worsened in physical disability. Types I and II showed a 5-year MRI phenotype conversion rate of 33% and 46%, whereas III and IV had >90% stability. Type II switched primarily to IV (91%); type I switched primarily to II (47%) or III (37%). Baseline higher age (p = 0.006) and lower BPF (p < 0.001) predicted 5-year phenotype conversion. Each MRI phenotype demonstrated an miRNA signature whose underlying biology implicates blood-brain barrier pathology: hsa.miR.22.3p, hsa.miR.361.5p, and hsa.miR.345.5p were the most valid differentiators of MRI phenotypes.

Conclusions

MRI-defined MS phenotypes show high conversion rates characterized by the continuation of either predominant neurodegeneration or inflammation and support the partial independence of these 2 measures. MicroRNA signatures of these phenotypes suggest a role for blood-brain barrier integrity.

Uveitis and Multiple Sclerosis: Potential Common Causal Mutations

Uveitis, defined as inflammation of the uveal tract of the eye, is a leading cause of blindness and visual impairment throughout the world. The etiology of uveitis is complex, and autoimmunity plays a major role in its pathogenesis. Intermediate uveitis (IU), a subtype of ocular inflammation, has been associated with systemic autoimmune disorders, specifically with multiple sclerosis (MS). This article reports a rare three-generation family with several members affected by IU (four siblings) and comorbid MS (two siblings fulfilling MS diagnostic criteria and a third sibling presenting some neurological symptoms). Based on the clinical findings, we captured and sequenced whole exomes of seven pedigree members (affected and unaffected). Using a recessive model of transmission with full penetrance, we applied genetic linkage analysis to define minimal critical regions (MCRs) in suggestive or nominal regions of linkage. In these MCRs, we defined functional (some pathogenic), novel, and rare mutations that segregated as homozygous in affected and heterozygous in unaffected family members. The genes harboring these mutations, including DGKI, TNFRSF10A, GNGT1, CPAMD8, and BAFF, which are expressed in both eye and brain tissues and/or are related to autoimmune diseases, provide new avenues to evaluate the inherited causes of these devastating autoimmune conditions.

Relation of intrathecal oligoclonal band production to inflammatory mediator and immunotherapy response in 208 children with OMS

In 208 children with opsoclonus-myoclonus syndrome (OMS), CSF IgG oligoclonal bands (OCB) and 22 immunomarkers in CSF and 21 in serum/blood were measured. In 36 untreated OMS, 58% were OCB(+), whereas 55% of treated OMS were OCB(-). OCB positivity or negativity did not alter concentrations or frequencies of immunomarkers. The phenotypes of OCB(+) and OCB(-) patients were not distinctive. CSF B cells were expanded in untreated OMS regardless of OCB positivity. These data reveal a much higher frequency of OCB positivity in untreated OMS than previously realized and a disconnect between intrathecal OCB and inflammatory mediator production.

Up-regulation of chemokine CXCL13 in systemic candidiasis

Candida albicans is the leading cause of healthcare associated bloodstream infections. Chemokine CXCL13 is well-known involved in inflammation, but its role in candidemia has not been assessed. Our study firstly demonstrated that serum CXCL13 levels were significantly elevated in candidemic patients compared with bacteremic patients and control subjects by ELISA, and CXCL13 concentrations were positively and significantly correlated with clinical Sequential Organ Failure Assessment (SOFA) scores and several laboratory parameters in patients. Moreover, ROC curve analysis showed the diagnostic efficiency of CXCL13 was superior to CRP and PCT. To further study the role of CXCL13, a mouse model was established. Importantly, the data showed the dramatically elevated levels of CXCL13 in mice serum and infected kidney, were significantly correlated with renal fungal burden and pathology scores. In conclusion, our results indicated that CXCL13 had strong potential as a novel biomarker of diagnosis and prognosis for candidemia.