Soluble CD27 is an intrathecal biomarker of T-cell-mediated lesion activity in multiple sclerosis.

OBJECTIVE: Soluble CD27 is a promising cerebrospinal fluid inflammatory biomarker in multiple sclerosis. In this study, we investigate relevant immune and neuro-pathological features of soluble CD27 in multiple sclerosis. METHODS: Protein levels of soluble CD27 were correlated to inflammatory cell subpopulations and inflammatory cytokines and chemokines detected in cerebrospinal fluid of 137 patients with multiple sclerosis and 47 patients with inflammatory and non-inflammatory neurological disease from three independent cohorts. Production of soluble CD27 was investigated in cell cultures of activated T and B cells and CD27-knockout T cells. In a study including matched cerebrospinal fluid and post-mortem brain tissues of patients with multiple sclerosis and control cases, levels of soluble CD27 were correlated with perivascular and meningeal infiltrates and with neuropathological features. RESULTS: We demonstrate that soluble CD27 favours the differentiation of interferon-γ-producing T cells and is released through a secretory mechanism activated by TCR engagement and regulated by neutral sphingomyelinase. We also show that the levels of soluble CD27 correlate with the representation of inflammatory T cell subsets in the CSF of patients with relapsing-remitting multiple sclerosis and with the magnitude of perivascular and meningeal CD27 + CD4 + and CD8 + T cell infiltrates in post-mortem central nervous system tissue, defining a subgroup of patients with extensive active inflammatory lesions. INTERPRETATION: Our results demonstrate that soluble CD27 is a biomarker of disease activity, potentially informative for personalized treatment and monitoring of treatment outcomes.

Serum biomarker levels predict disability progression in patients with primary progressive multiple sclerosis.

BACKGROUND: We aimed to investigate the potential of serum biomarker levels to predict disability progression in a multicentric real-world cohort of patients with primary progressive multiple sclerosis (PPMS). METHODS: A total of 141 patients with PPMS from 18 European MS centres were included. Disability progression was investigated using change in Expanded Disability Status Scale (EDSS) score over three time intervals: baseline to 2 years, 6 years and to the last follow-up. Serum levels of neurofilament light chain (sNfL), glial fibrillar acidic protein (sGFAP) and chitinase 3-like 1 (sCHI3L1) were measured using single-molecule array assays at baseline. Correlations between biomarker levels, and between biomarkers and age were quantified using Spearman's r. Univariable and multivariable linear models were performed to assess associations between biomarker levels and EDSS change over the different time periods. RESULTS: Median (IQR) age of patients was 52.9 (46.4-58.5) years, and 58 (41.1%) were men. Median follow-up time was 9.1 (7.0-12.6) years. Only 8 (5.7%) patients received treatment during follow-up. sNfL and sGFAP levels were moderately correlated (r=0.43) and both weakly correlated with sCHI3L1 levels (r=0.19 and r=0.17, respectively). In multivariable analyses, levels of the three biomarkers were associated with EDSS changes across all time periods. However, when analysis was restricted to non-inflammatory patients according to clinical and radiological parameters (n=64), only sCHI3L1 levels remained associated with future EDSS change. CONCLUSIONS: Levels of sNfL, sGFAP and sCHI3L1 are prognostic biomarkers associated with disability progression in patients with PPMS, being CHI3L1 findings less dependent on the inflammatory component associated with disease progression.

Cerebrospinal fluid kappa free light chains for the diagnosis of multiple sclerosis: A systematic review and meta-analysis.

BACKGROUND: Intrathecal immunoglobulin-G synthesis is a hallmark of multiple sclerosis (MS), which can be detected by oligoclonal IgG bands (OCB) or by κ-free light chains (κ-FLC) in cerebrospinal fluid. OBJECTIVE: To perform a systematic review and meta-analysis to evaluate whether κ-FLC index has similar diagnostic value to identify patients with clinically isolated syndrome (CIS) or MS compared to OCB, and to determine κ-FLC index cut-off. METHODS: PubMed was searched for studies that assessed diagnostic sensitivity and specificity of κ-FLC index and OCB to discriminate CIS/MS patients from control subjects. Two reviewers following preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines performed study eligibility assessment and data extraction. Findings from studies were analyzed with bivariate mixed models. RESULTS: A total of 32 studies were included in the meta-analysis to evaluate diagnostic value of κ-FLC index. Sensitivity and specificity ranged from 52% to 100% (weighted average: 88%) and 69% to 100% (89%) for κ-FLC index and from 37% to 100% (85%) and 74% to 100% (92%) for OCB. Mean difference of sensitivity and specificity between κ-FLC index and OCB was 2 and -4 percentage points. Diagnostic accuracy determined by mixed models revealed no significant difference between κ-FLC index and OCB. A discriminatory cut-off for κ-FLC index was determined at 6.1. CONCLUSION: The findings indicate that κ-FLC index has similar diagnostic accuracy in MS as OCB.

Severe Acute Respiratory Syndrome Coronavirus 2 Spreads to Lymph Nodes and Strongly Expands CD4+ Effector Memory RA Cells in a Patient With Mild Coronavirus Disease 2019.

A woman with mild coronavirus disease 2019 developed cervical adenopathy, being diagnosed of Epstein-Barr virus infectious mononucleosis. We performed fine needle aspiration, and demonstrate that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is found in lymph nodes even in mild disease along with a strong expansion of terminally differentiated effector memory CD4+ T cells, a cell population that is practically absent in lymph nodes.

Oligoclonal IgM bands in the cerebrospinal fluid of patients with relapsing MS to inform long-term MS disability.

BACKGROUND: Prognostic markers are needed to guide multiple sclerosis (MS) management in the context of large availability of disease-modifying drugs (DMDs). OBJECTIVE: To investigate the role of cerebrospinal fluid (CSF) markers to inform long-term MS outcomes. METHODS: Demographic features, IgM index, oligoclonal IgM bands (OCMB), lipid-specific OCMB, CSF neurofilament light chain protein levels, expanded disability status scale (EDSS), relapses and DMD use over the study period and peripapillary retinal nerve fiber layer (pRNFL) and ganglion cell plus inner plexiform layer (GCIPL) thicknesses in non-optic neuritis eyes (end of follow-up) were collected from relapsing MS (RMS) patients with CSF obtained ⩽2 years after MS onset prospectively followed at the Hospital Clinic of Barcelona. We assessed associations between CSF markers and MS outcomes using multivariable models. RESULTS: A total of 89 patients (71 females; median 32.9 years of age) followed over a median of 9.6 years were included. OCMB were associated with a 33% increase in the annualized relapse rate (ARR; p = 0.06), higher odds for high-efficacy DMDs use (OR = 4.8; 95% CI = (1.5, 16.1)), thinner pRNFL (ß = -4.4; 95% CI = (-8.6, -0.2)) and GCIPL (ß = -2.9; 95% CI = (-5.9, +0.05)), and higher rates to EDSS ⩾ 3.0 (HR = 4.4; 95% CI = (1.6, 11.8)) and EDSS ⩾ 4.0 (HR = 5.4; 95% CI = (1.1, 27.1)). No overall associations were found for other CSF markers. CONCLUSION: The presence of OCMB was associated with unfavorable long-term outcomes. OCMB should be determined in RMS to inform long-term prognosis.

Phenotypic and Ig Repertoire Analyses Indicate a Common Origin of IgD-CD27- Double Negative B Cells in Healthy Individuals and Multiple Sclerosis Patients.

IgD-CD27- double negative (DN) B cells with proinflammatory characteristics are abnormally elevated in a proportion of multiple sclerosis (MS) patients. In this study, the origin and selection characteristics of DN B cells were studied in MS patients and healthy controls (HC). Expression of developmental markers on peripheral blood DN, IgD-CD27+ class-switched memory (CSM) and IgD+CD27- naive B cells of HC (n = 48) and MS patients (n = 96) was determined by flow cytometry. High-throughput adaptive immune receptor repertoire sequencing was performed on peripheral blood DN and CSM B cells of HC and MS patients (n = 3 each). DN B cells from HC and MS patients showed similar phenotypic and Ig repertoire characteristics. Phenotypic analysis indicated a mature state of DN B cells by low CD5, CD10, and CD38 expression. However, the frequency of CD95+ and IgA+ cells was lower in DN versus CSM B cells. DN B cells are Ag experienced, as shown by somatic hypermutation of their Ig genes in adaptive immune receptor repertoire sequencing, although they showed a lower mutation load than CSM B cells. Shared clones were found between DN and CSM B cells, although >95% of the clones were unique to each population, and differences in V(D)J usage and CDR3 physicochemical properties were found. Thus, DN B cells arise in HC and MS patients via a common developmental pathway that is probably linked to immune aging. However, DN and CSM B cells develop through unique differentiation pathways, with most DN B cells representing an earlier maturation state.

NLRP3 inflammasome as prognostic factor and therapeutic target in primary progressive multiple sclerosis patients.

Primary progressive multiple sclerosis is a poorly understood disease entity with no specific prognostic biomarkers and scarce therapeutic options. We aimed to identify disease activity biomarkers in multiple sclerosis by performing an RNA sequencing approach in peripheral blood mononuclear cells from a discovery cohort of 44 untreated patients with multiple sclerosis belonging to different clinical forms and activity phases of the disease, and 12 healthy control subjects. A validation cohort of 58 patients with multiple sclerosis and 26 healthy control subjects was included in the study to replicate the RNA sequencing findings. The RNA sequencing revealed an interleukin 1 beta (IL1B) signature in patients with primary progressive multiple sclerosis. Subsequent immunophenotyping pointed to blood monocytes as responsible for the IL1B signature observed in this group of patients. Functional experiments at baseline measuring apoptosis-associated speck-like protein containing a CARD (ASC) speck formation showed that the NOD-leucine rich repeat and pyrin containing protein 3 (NLRP3) inflammasome was overactive in monocytes from patients with primary progressive multiple sclerosis, and canonical NLRP3 inflammasome activation with a combination of ATP plus lipopolysaccharide was associated with increased IL1B production in this group of patients. Primary progressive multiple sclerosis patients with high IL1B gene expression levels in peripheral blood mononuclear cells progressed significantly faster compared to patients with low IL1B levels based on the time to reach an EDSS of 6.0 and the Multiple Sclerosis Severity Score. In agreement with peripheral blood findings, both NLRP3 and IL1B expression in brain tissue from patients with primary progressive multiple sclerosis was mainly restricted to cells of myeloid lineage. Treatment of mice with a specific NLRP3 inflammasome inhibitor attenuated established experimental autoimmune encephalomyelitis disease severity and improved CNS histopathology. NLRP3 inflammasome-specific inhibition was also effective in reducing axonal damage in a model of lipopolysaccharide-neuroinflammation using organotypic cerebellar cultures. Altogether, these results point to a role of IL1B and the NLRP3 inflammasome as prognostic biomarker and potential therapeutic target, respectively, in patients with primary progressive multiple sclerosis.

Neurofilament light chain and oligoclonal bands are prognostic biomarkers in radiologically isolated syndrome.

The prognostic role of cerebrospinal fluid molecular biomarkers determined in early pathogenic stages of multiple sclerosis has yet to be defined. In the present study, we aimed to investigate the prognostic value of chitinase 3 like 1 (CHI3L1), neurofilament light chain, and oligoclonal bands for conversion to clinically isolated syndrome and to multiple sclerosis in 75 patients with radiologically isolated syndrome. Cerebrospinal fluid levels of CHI3L1 and neurofilament light chain were measured by enzyme-linked immunosorbent assay. Uni- and multivariable Cox regression models including as covariates age at diagnosis of radiologically isolated syndrome, number of brain lesions, sex and treatment were used to investigate associations between cerebrospinal fluid CHI3L1 and neurofilament light chain levels and time to conversion to clinically isolated syndrome and multiple sclerosis. Neurofilament light chain levels and oligoclonal bands were independent risk factors for the development of clinically isolated syndrome (hazard ratio = 1.02, P = 0.019, and hazard ratio = 14.7, P = 0.012, respectively) and multiple sclerosis (hazard ratio = 1.03, P = 0.003, and hazard ratio = 8.9, P = 0.046, respectively). The best cut-off to classify cerebrospinal fluid neurofilament light chain levels into high and low was 619 ng/l, and high neurofilament light chain levels were associated with a trend to shorter time to clinically isolated syndrome (P = 0.079) and significant shorter time to multiple sclerosis (P = 0.017). Similarly, patients with radiologically isolated syndrome presenting positive oligoclonal bands converted faster to clinically isolated syndrome and multiple sclerosis (P = 0.005 and P = 0.008, respectively). The effects of high neurofilament light chain levels shortening time to clinically isolated syndrome and multiple sclerosis were more pronounced in radiologically isolated syndrome patients with ≥37 years compared to younger patients. Cerebrospinal fluid CHI3L1 levels did not influence conversion to clinically isolated syndrome and multiple sclerosis in radiologically isolated syndrome patients. Overall, these findings suggest that cerebrospinal neurofilament light chain levels and oligoclonal bands are independent predictors of clinical conversion in patients with radiologically isolated syndrome. The association with a faster development of multiple sclerosis reinforces the importance of cerebrospinal fluid analysis in patients with radiologically isolated syndrome.

MRI phenotypes with high neurodegeneration are associated with peripheral blood B-cell changes.

Little is known about the mechanisms leading to neurodegeneration in multiple sclerosis (MS) and the role of peripheral blood cells in this neurodegenerative component. We aimed to correlate brain radiological phenotypes defined by high and low neurodegeneration with gene expression profiling of peripheral blood mononuclear cells (PBMC) from MS patients. Magnetic resonance imaging (MRI) scans from 64 patients with relapsing-remitting MS (RRMS) were classified into radiological phenotypes characterized by low (N = 27) and high (N = 37) neurodegeneration according to the number of contrast-enhancing lesions, the relative volume of non-enhancing black holes on T1-weighted images, and the brain parenchymal fraction. Gene expression profiling was determined in PBMC using microarrays, and validation of selected genes was performed by polymerase chain reaction (PCR). B-cell immunophenotyping was conducted by flow cytometry. Microarray analysis revealed the B-cell specific genes FCRL1, FCRL2, FCRL5 (Fc receptor-like 1, 2 and 5 respectively), and CD22 as the top differentially expressed genes between patients with high and low neurodegeneration. Levels for these genes were significantly down-regulated in PBMC from patients with MRI phenotypes characterized by high neurodegeneration and microarray findings were validated by PCR. In patients with high neurodegeneration, immunophenotyping showed a significant increase in the expression of the B-cell activation markers CD80 in naïve B cells (CD45+/CD19+/CD27-/IgD+), unswitched memory B cells (CD45+/CD19+/CD27+/IgD+), and switched memory B cells (CD45+/CD19+/CD27+/IgD-), and CD86 in naïve and switched memory B cells. These results suggest that RRMS patients with radiological phenotypes showing high neurodegeneration have changes in B cells characterized by down-regulation of B-cell-specific genes and increased activation status.

Circulating EZH2-positive T cells are decreased in multiple sclerosis patients.

BACKGROUND: Recent studies in experimental autoimmune encephalomyelitis, an animal model of multiple sclerosis (MS), suggest an involvement of the histone methyltransferase enhancer of zeste 2 polycomb repressive complex 2 subunit (EZH2) in important processes such as cell adhesion and migration. METHODS: Here, we aimed to expand these initial observations by investigating the role of EZH2 in MS. mRNA expression levels for EZH2 were measured by real-time PCR in peripheral blood mononuclear cells (PBMC) from 121 MS patients (62 untreated and 59 receiving treatment) and 24 healthy controls. RESULTS: EZH2 expression levels were decreased in PBMC from untreated patients compared to that from controls, and treatment significantly upregulated EZH2 expression. Expression of miR-124 was increased in MS patients compared to controls. Blood immunophenotyping revealed EZH2 expression mostly restricted to CD4+ and CD8+ T cells, and circulating EZH2+ CD4+ and CD8+ T cells were decreased in untreated MS patients compared to controls. CD8+ T cells expressing EZH2 exhibited a predominant central memory phenotype, whereas EZH2+ CD4+ T cells were of effector memory nature, and both T cell subsets produced TNF-α. EZH2+ T cells were enriched in the cerebrospinal fluid compartment compared to blood and were found in chronic active lesions from MS patients. EZH2 inhibition and microarray analysis in PBMC was associated with significant downregulation of key T cell adhesion molecules. CONCLUSION: These findings suggest a role of EZH2 in the migration of T cells in MS patients. The observation of TNF-α expression by CD4+ and CD8+ T cells expressing EZH2 warrants additional studies to explore more in depth the pathogenic potential of EZH2+-positive cells in MS.

Exome sequencing study in patients with multiple sclerosis reveals variants associated with disease course.

BACKGROUND: It remains unclear whether disease course in multiple sclerosis (MS) is influenced by genetic polymorphisms. Here, we aimed to identify genetic variants associated with benign and aggressive disease courses in MS patients. METHODS: MS patients were classified into benign and aggressive phenotypes according to clinical criteria. We performed exome sequencing in a discovery cohort, which included 20 MS patients, 10 with benign and 10 with aggressive disease course, and genotyping in 2 independent validation cohorts. The first validation cohort encompassed 194 MS patients, 107 with benign and 87 with aggressive phenotypes. The second validation cohort comprised 257 patients, of whom 224 patients had benign phenotypes and 33 aggressive disease courses. Brain immunohistochemistries were performed using disease course associated genes antibodies. RESULTS: By means of single-nucleotide polymorphism (SNP) detection and comparison of allele frequencies between patients with benign and aggressive phenotypes, a total of 16 SNPs were selected for validation from the exome sequencing data in the discovery cohort. Meta-analysis of genotyping results in two validation cohorts revealed two polymorphisms, rs28469012 and rs10894768, significantly associated with disease course. SNP rs28469012 is located in CPXM2 (carboxypeptidase X, M14 family, member 2) and was associated with aggressive disease course (uncorrected p value < 0.05). SNP rs10894768, which is positioned in IGSF9B (immunoglobulin superfamily member 9B) was associated with benign phenotype (uncorrected p value < 0.05). In addition, a trend for association with benign phenotype was observed for a third SNP, rs10423927, in NLRP9 (NLR family pyrin domain containing 9). Brain immunohistochemistries in chronic active lesions from MS patients revealed expression of IGSF9B in astrocytes and macrophages/microglial cells, and expression of CPXM2 and NLRP9 restricted to brain macrophages/microglia. CONCLUSIONS: Genetic variants located in CPXM2, IGSF9B, and NLRP9 have the potential to modulate disease course in MS patients and may be used as disease activity biomarkers to identify patients with divergent disease courses. Altogether, the reported results from this study support the influence of genetic factors in MS disease course and may help to better understand the complex molecular mechanisms underlying disease pathogenesis.

Optimal response to dimethyl fumarate associates in MS with a shift from an inflammatory to a tolerogenic blood cell profile.

BACKGROUND: The precise mechanism of action of dimethyl fumarate (DMF) treatment in MS remains unknown. OBJECTIVE: To identify the changes in the blood lymphocyte profile of MS patients predicting no evidence of disease activity (NEDA) status after DMF treatment. METHODS: We studied blood lymphocyte subsets of 64 MS patients treated with DMF at baseline and after 6 months of treatment by flow cytometry. NEDA (41 patients) or ongoing disease activity (ODA, 23 patients) were monitored after a year of follow-up. RESULTS: During treatment, all patients experienced an increase in the naive T cells and a decrease in effector memory ones. However, only NEDA patients showed a significant reduction in central memory CD4+ and CD8+ T cells, memory B cells, CD4+ T cells producing interferon (IFN)-gamma, CD8+ T cells producing tumor necrosis factor-alpha (TNF-alpha), and IFN-gamma and B cells producing TNF-alpha. Additionally, they had an increase in regulatory CD56bright cells not observed in ODA group. After treatment, there was a negative correlation between CD56bright cells and CD8+ T cells producing IFN-gamma and TNF-alpha. CONCLUSION: A pro-tolerogenic shift in the blood leukocyte profile associates with an optimal response to DMF in MS.

NLRP3 polymorphisms and response to interferon-beta in multiple sclerosis patients.

We aimed to investigate whether NLR family, pyrin domain containing 3 (NLRP3) polymorphisms are associated with the response to interferon-beta (IFNß) in multiple sclerosis (MS) patients. A total of 14 NLRP3 polymorphisms were genotyped in a cohort of 665 relapsing-remitting MS patients recruited across 5 centers and classified into responders and non-responders according to clinical-radiological criteria after 1 year of IFNß treatment. A meta-analysis failed to demonstrate significant associations between the response to IFNß and NLRP3 polymorphisms. These findings do not support a role of polymorphisms located in the NLRP3 gene and the response to IFNß in MS patients.

Decreased soluble IFN-ß receptor (sIFNAR2) in multiple sclerosis patients: A potential serum diagnostic biomarker.

BACKGROUND: The soluble isoform of the interferon-ß (IFN-ß) receptor (sIFNAR2) could modulate the activity of both endogenous and systemically administered IFN-ß. Previously, we described lower serum sIFNAR2 levels in untreated multiple sclerosis (MS) than in healthy controls (HCs). OBJECTIVE: To assess sIFNAR2 levels in a new cohort of MS patients and HCs, as well as in patients with clinically isolated syndrome (CIS) and with other inflammatory neurological disorders (OIND) and to assess its ability as a diagnostic biomarker. METHODS: The cross-sectional study included 148 MS (84 treatment naive and 64 treated), 87 CIS, 42 OIND, and 96 HCs. Longitudinal study included 94 MS pretreatment and after 1 year of therapy with IFN-ß, glatiramer acetate (GA), or natalizumab. sIFNAR2 serum levels were measured by a quantitative ELISA developed and validated in our laboratory. RESULTS: Naive MS and CIS patients showed significantly lower sIFNAR2 levels than HCs and OIND patients. The sensitivity and specificity to discriminate between MS and OIND, for a sIFNAR2 cutoff value of 122.02 ng/mL, were 70.1%, and 79.4%, respectively. sIFNAR2 increased significantly in IFN-ß-treated patients during the first year of therapy in contrast to GA- and natalizumab-treated patients who showed non-significant changes. CONCLUSION: The results suggest that sIFNAR2 could be a potential diagnostic biomarker for MS.

Lipid-specific immunoglobulin M bands in cerebrospinal fluid are associated with a reduced risk of developing progressive multifocal leukoencephalopathy during treatment with natalizumab.

OBJECTIVE: Progressive multifocal leukoencephalopathy (PML) is a serious side effect associated with natalizumab treatment in multiple sclerosis (MS). PML risk increases in individuals seropositive for anti-John Cunningham virus (JC) antibodies, with prolonged duration of natalizumab treatment, and with prior exposure to immunosuppressants. We explored whether the presence of lipid-specific immunoglobulin M oligoclonal bands in cerebrospinal fluid (CSF; IgM bands), a recognized marker of highly inflammatory MS, may identify individuals better able to counteract the potential immunosuppressive effect of natalizumab and hence be associated with a reduced risk of developing PML. METHODS: We studied 24 MS patients who developed PML and another 343 who did not suffer this opportunistic infection during natalizumab treatment. Patients were recruited at 25 university hospitals. IgM bands were studied by isoelectric focusing and immunodetection. CSF lymphocyte counts were explored in 151 MS patients recruited at Ramon y Cajal Hospital in Madrid, Spain. RESULTS: IgM bands were independently associated with decreased PML risk (odds ratio [OR] = 45.9, 95% confidence interval [CI] = 5.9-339.3, p < 0.0001) in patients treated with natalizumab. They were also associated with significantly higher CSF CD4, CD8, and B-cell numbers. Patients positive for IgM bands and anti-JC antibodies had similar levels of reduced PML risk to those who were anti-JC negative (OR = 1.55, 95% CI = 0.09-25.2, p = 1.0). Higher risk was observed in patients positive for anti-JC antibodies and negative for IgM bands (19% of the total cohort, OR = 59.71, 95% CI = 13.6-262.2). INTERPRETATION: The presence of IgM bands reflects a process that may diminish the risk of PML by counteracting the excess of immunosuppression that may occur during natalizumab therapy.

Adaptive natural killer cell response to cytomegalovirus and disability progression in multiple sclerosis.

BACKGROUND: Human cytomegalovirus (HCMV) causes a highly prevalent infection which may have a multifaceted impact on chronic inflammatory disorders. However, its potential influence in multiple sclerosis (MS) remains controversial. The HCMV-host interaction may induce an adaptive reconfiguration of the natural killer (NK) cell compartment, whose hallmark is a persistent expansion of peripheral NKG2C+ NK-cells. OBJECTIVE: The purpose of this study was to evaluate whether the HCMV-driven NKG2C+ NK-cell expansion is related to the MS clinical course. METHODS: Multicentre analysis of NKG2C expression and genotype according to HCMV serostatus and time of assignment of irreversible disability scores in 246 MS patients prospectively followed up in our institutions. RESULTS: NKG2C expression was unrelated to disease-modifying drugs, remained stable under steady-state conditions, and was higher in HCMV(+) NKG2C(+/+) homozygous individuals. NKG2C+ NK-cell expansion in HCMV(+) patients, as compared to HCMV(+) or HCMV(-) patients with lower NKG2C+ NK-cells proportions, conferred a lower risk of progression in Cox regression analysis (Expanded Disability Status Scale (EDSS)>3.0, hazard ratio (HR)=0.33, 95% confidence interval (CI) 0.15-0.71, p=0.005; EDSS>5.5, HR=0.23, 95% CI 0.07-0.74, p=0.014). Neither HCMV serostatus nor NKG2C genotype appeared to be related to disability progression. CONCLUSIONS: HCMV may exert a beneficial influence on MS, decreasing the risk of disability progression in those patients displaying a virus-driven NKG2C+ NK-cell expansion.

Sperm-associated antigen 16 is a novel target of the humoral autoimmune response in multiple sclerosis.

We have previously identified eight novel autoantibody targets in the cerebrospinal fluid of multiple sclerosis (MS) patients, including sperm-associated Ag 16 (SPAG16). In the current study, we further investigated the autoantibody response against SPAG16-a protein with unknown function in the CNS-and its expression in MS pathology. Using isoelectric focusing, we detected SPAG16-specific oligoclonal bands in the cerebrospinal fluid of 5 of 23 MS patients (22%). Analysis of the anti-SPAG16 Ab reactivity in the plasma of a total of 531 donors using ELISA demonstrated significantly elevated anti-SPAG16 Ab levels (p = 0.002) in 32 of 153 MS patients (21%) compared with all other control groups with 95% specificity for the disease. To investigate the pathologic relevance of anti-SPAG16 Abs in vivo, anti-SPAG16 Abs were injected in mice with experimental autoimmune encephalomyelitis, resulting in a significant disease exacerbation. Finally, we demonstrated a consistent upregulation of SPAG16 in MS brain and experimental autoimmune encephalomyelitis spinal cord lesions, more specifically in reactive astrocytes. We conclude that SPAG16 is a novel autoantibody target in a subgroup of MS patients and in combination with other diagnostic criteria, elevated levels of anti-SPAG16 Abs could be used as a biomarker for diagnosis. Furthermore, the pathologic relevance of anti-SPAG16 Abs was shown in vivo.

Chitinase 3-like 1: prognostic biomarker in clinically isolated syndromes.

Chitinase 3-like 1 (CHI3L1) has been proposed as a biomarker associated with the conversion to clinically definite multiple sclerosis in patients with clinically isolated syndromes, based on the finding of increased cerebrospinal fluid CHI3L1 levels in clinically isolated syndrome patients who later converted to multiple sclerosis compared to those who remained as clinically isolated syndrome. Here, we aimed to validate CHI3L1 as a prognostic biomarker in a large cohort of patients with clinically isolated syndrome. This is a longitudinal cohort study of clinically isolated syndrome patients with clinical, magnetic resonance imaging, and cerebrospinal fluid data prospectively acquired. A total of 813 cerebrospinal fluid samples from patients with clinically isolated syndrome were recruited from 15 European multiple sclerosis centres. Cerebrospinal fluid CHI3L1 levels were measured by enzyme-linked immunosorbent assay. Multivariable Cox regression models were used to investigate the association between cerebrospinal fluid CHI3L1 levels and time to conversion to multiple sclerosis and time to reach Expanded Disability Status Scale 3.0. CHI3L1 levels were higher in patients who converted to clinically definite multiple sclerosis compared to patients who continued as clinically isolated syndrome (P = 8.1 × 10(-11)). In the Cox regression analysis, CHI3L1 levels were a risk factor for conversion to multiple sclerosis (hazard ratio = 1.7; P = 1.1 × 10(-5) using Poser criteria; hazard ratio = 1.6; P = 3.7 × 10(-6) for McDonald criteria) independent of other covariates such as brain magnetic resonance imaging abnormalities and presence of cerebrospinal fluid oligoclonal bands, and were the only significant independent risk factor associated with the development of disability (hazard ratio = 3.8; P = 2.5 × 10(-8)). High CHI3L1 levels were associated with shorter time to multiple sclerosis (P = 3.2 × 10(-9) using Poser criteria; P = 5.6 × 10(-11) for McDonald criteria) and more rapid development of disability (P = 1.8 × 10(-10)). These findings validate cerebrospinal fluid CHI3L1 as a biomarker associated with the conversion to multiple sclerosis and development of disability and reinforce the prognostic role of CHI3L1 in patients with clinically isolated syndrome. We propose that determining cerebrospinal fluid chitinase 3-like 1 levels at the time of a clinically isolated syndrome event will help identify those patients with worse disease prognosis.

Immunoglobulin M oligoclonal bands: biomarker of targetable inflammation in primary progressive multiple sclerosis.

OBJECTIVE: To identify a biomarker distinguishing patients who, despite a primary progressive multiple sclerosis (PPMS) clinical course, may nonetheless benefit from immune therapy. METHODS: The presence or absence of both immunoglobulin (Ig) G and IgM oligoclonal bands (OCB) was blindly examined in paired cerebrospinal fluid (CSF) and serum samples from a large PPMS patient cohort, and related to clinical and imaging evidence of focal inflammatory disease activity. RESULTS: Using both cross-sectional samples and serial sampling in a subgroup of patients followed prospectively as part of the placebo-controlled OLYMPUS study of rituximab in PPMS, we found that the presence of CSF-restricted IgM OCB (but not of IgG OCB) is associated with an active inflammatory disease phenotype in PPMS patients. This finding was confirmed in an independent, multicenter validation cohort. INTERPRETATION: The presence of CSF IgM OCB may be a biomarker for a subset of PPMS patients with more active inflammatory disease, who may benefit from immune-directed treatments.

Intrathecal somatic hypermutation of IgM in multiple sclerosis and neuroinflammation.

Intrathecal oligoclonal bands of the cerebrospinal fluid are considered the most important immunological biomarkers of multiple sclerosis. They typically consist of clonally expanded IgG antibodies that underwent affinity maturation during sustained stimulation by largely unknown antigens. In addition, ∼40% of patients with multiple sclerosis have oligoclonal bands that consist of expanded IgM antibodies. We investigated the molecular composition of IgM- and IgG-chains from cerebrospinal fluid of 12 patients with multiple sclerosis, seven patients with other neurological diseases, and eight healthy control subjects by high-throughput deep-sequencing and single-cell PCR. Further, we studied the expression of activation-induced cytidine deaminase, the key enzyme for affinity maturation of antibodies, in cerebrospinal fluid samples of 16 patients. From the cerebrospinal fluid of two multiple sclerosis patients we isolated single B cells and investigated the co-expression of antibody chains with activation-induced cytidine deaminase. In striking contrast to IgM-chains from peripheral blood, IgM-chains from cerebrospinal fluid of patients with multiple sclerosis or neuroborreliosis showed a high degree of somatic hypermutation. We found a high content of mutations that caused amino acid exchanges as compared to silent mutations. In addition, more mutations were found in the complementarity determining regions of the IgM-chains, which interact with yet unknown antigens, as compared to framework regions. Both observations provide evidence for antigen-driven affinity maturation. Furthermore, single B cells from the cerebrospinal fluid of patients with multiple sclerosis co-expressed somatically hypermutated IgM-chains and activation-induced cytidine deaminase, an enzyme that is crucial for somatic hypermutation and class switch recombination of antibodies and is normally expressed during activation of B cells in germinal centres. Clonal tracking of particular IgM(+) B cells allowed us to relate unmutated ancestor clones in blood to hypermutated offspring clones in CSF. Unexpectedly, however, we found no evidence for intrathecal isotype switching from IgM to IgG. Our data suggest that the intrathecal milieu sustains a germinal centre-like reaction with clonal expansion and extensive accumulation of somatic hypermutation in IgM-producing B cells.