Short-chain fatty acids during pregnancy in multiple sclerosis: A prospective cohort study

BACKGROUND AND PURPOSE

Short-chain fatty acids (SCFAs) can have pro- or anti-inflammatory properties, but their relationship with multiple sclerosis (MS) relapses during pregnancy remains unknown. This study aimed to explore SCFA profiles in MS patients during pregnancy and to assess their association with the appearance of relapses during pregnancy and postpartum.

METHODS

We prospectively included 53 pregnant MS patients and 21 healthy control women. Patients were evaluated during pregnancy and puerperium. SCFAs were measured by liquid chromatography-mass spectrometry.

RESULTS

Sixteen patients (32%) had relapses during pregnancy or puerperium, and 37 (68%) did not. All MS patients showed significant increases in acetate levels during pregnancy and the postpartum period compared to non-MS women. However, propionate and butyrate values were associated with disease activity. Their values were higher in nonrelapsing patients and remained similar to the control group in relapsing patients. The variable that best identified active patients was the propionate/acetate ratio. Ratios of <0.36 during the first trimester were associated with higher inflammatory activity (odds ratio = 165, 95% confidence interval = 10.2-239.4, p < 0.01). Most nonrelapsing patients showed values of >0.36, which were similar to those in healthy pregnant women.

CONCLUSIONS

Low propionate/acetate ratio values during the first trimester of gestation identified MS patients at risk of relapses during pregnancy and the postpartum period.

Identification of the Immunological Changes Appearing in the CSF During the Early Immunosenescence Process Occurring in Multiple Sclerosis

Patients with multiple sclerosis (MS) suffer with age an early immunosenescence process, which influence the treatment response and increase the risk of infections. We explored whether lipid-specific oligoclonal IgM bands (LS-OCMB) associated with highly inflammatory MS modify the immunological profile induced by age in MS. This cross-sectional study included 263 MS patients who were classified according to the presence (M+, n=72) and absence (M-, n=191) of LS-OCMB. CSF cellular subsets and molecules implicated in immunosenescence were explored. In M- patients, aging induced remarkable decreases in absolute CSF counts of CD4+ and CD8+ T lymphocytes, including Th1 and Th17 cells, and of B cells, including those secreting TNF-alpha. It also increased serum anti-CMV IgG antibody titers (indicative of immunosenescence) and CSF CHI3L1 levels (related to astrocyte activation). In contrast, M+ patients showed an age-associated increase of TIM-3 (a biomarker of T cell exhaustion) and increased values of CHI3L1, independently of age. Finally, in both groups, age induced an increase in CSF levels of PD-L1 (an inductor of T cell tolerance) and activin A (part of the senescence-associated secretome and related to inflammaging). These changes were independent of the disease duration. Finally, this resulted in augmented disability. In summary, all MS patients experience with age a modest induction of T-cell tolerance and an activation of the innate immunity, resulting in increased disability. Additionally, M- patients show clear decreases in CSF lymphocyte numbers, which could increase the risk of infections. Thus, age and immunological status are important for tailoring effective therapies in MS.

Barcoded viral tracing of single-cell interactions in central nervous system inflammation

Cell-cell interactions control the physiology and pathology of the central nervous system (CNS). To study astrocyte cell interactions in vivo, we developed rabies barcode interaction detection followed by sequencing (RABID-seq), which combines barcoded viral tracing and single-cell RNA sequencing (scRNA-seq). Using RABID-seq, we identified axon guidance molecules as candidate mediators of microglia-astrocyte interactions that promote CNS pathology in experimental autoimmune encephalomyelitis (EAE) and, potentially, multiple sclerosis (MS). In vivo cell-specific genetic perturbation EAE studies, in vitro systems, and the analysis of MS scRNA-seq datasets and CNS tissue established that Sema4D and Ephrin-B3 expressed in microglia control astrocyte responses via PlexinB2 and EphB3, respectively. Furthermore, a CNS-penetrant EphB3 inhibitor suppressed astrocyte and microglia proinflammatory responses and ameliorated EAE. In summary, RABID-seq identified microglia-astrocyte interactions and candidate therapeutic targets.

New Algorithms Improving PML Risk Stratification in MS Patients Treated With Natalizumab

Overview: We assessed the role of age and disease activity as new factors contributing to establish the risk of progressive multifocal leucoencephalopathy in multiple sclerosis patients treated with natalizumab in 36 University Hospitals in Europe. We performed the study in 1,307 multiple sclerosis patients (70.8% anti-John Cunninghan virus positive antibodies) treated with natalizumab for a median time of 3.28 years. Epidemiological, clinical, and laboratory variables were collected. Lipid-specific IgM oligoclonal band status was available in 277 patients. Factors associated with progressive multifocal leucoencephalopathy onset were explored by uni- and multivariate logistic regression. Results: Thirty-five patients developed progressive multifocal leucoencephalopathy. The multivariate analysis identified anti-John Cunninghan virus antibody indices and relapse rate as the best predictors for the onset of this serious opportunistic infection in the whole cohort. They allowed to stratify progressive multifocal leucoencephalopathy risk before natalizumab initiation in individual patients [area under the curve (AUC) = 0.85]. The risk ranged from <1/3,300 in patients with anti-John Cunninghan virus antibody indices <0.9 and relapse rate >0.5, to 1/50 in the opposite case. In patients with lipid-specific IgM oligoclonal bands assessment, age at natalizumab onset, anti-John Cunninghan virus antibody indices, and lipid-specific IgM oligoclonal band status predicted progressive multifocal leucoencephalopathy risk (AUC = 0.92). The absence of lipid-specific IgM oligoclonal bands was the best individual predictor (OR = 40.94). The individual risk ranged from <1/10,000 in patients younger than 45 years at natalizumab initiation, who showed anti John Cunningham virus antibody indices <0.9 and lipid-specific IgM oligoclonal bands to 1/33 in the opposite case. Conclusions: In a perspective of personalized medicine, disease activity, anti-lipid specific IgM oligoclonal bands, anti Jonh Cunninghan virus antibody levels, and age can help tailor natalizumab therapy in multiple sclerosis patients, as predictors of progressive multifocal leucoencephalopathy.

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.

Possible role of HLA class-I genotype in SARS-CoV-2 infection and progression: A pilot study in a cohort of Covid-19 Spanish patients

Human Leukocyte Antigen (HLA) includes a large set of genes with important actions in immune response against viral infection. Numerous studies have revealed the existence of significant associations between certain HLA alleles and the susceptibility and prognosis of different infectious diseases. In this pilot study we analyse the binding affinity between 66 class I HLA alleles and SARS-CoV-2 viral peptides, and its association with the severity of the disease. A total of 45 Spanish patients with mild, moderate and severe SARS-CoV-2 infection were typed for HLA class I; after that, we analysed if an in silico model of HLA I-viral peptide binding affinity and classical HLA supertypes could be correlated to the severity of the disease. Our results suggest that patients with mild disease present Class I HLA molecules with a higher theoretical capacity for binding SARS-Cov-2 peptides and showed greater heterozygosity when comparing them with moderate and severe groups. In this regard, identifying HLA-SARS-CoV-2 peptides binding differences between individuals would help to clarify the heterogeneity of clinical responses to the disease and will also be useful to guide a personalized treatment according to its particular risk.

Targeted resequencing reveals rare variants enrichment in multiple sclerosis susceptibility genes

Although genome-wide association studies have identified a number of common variants associated with multiple sclerosis (MS) susceptibility, little is known about the relevance of rare variants. Here, we aimed to explore the role of rare variants in 14 MS risk genes (FCRL1, RGS1, TIMMDC1, HHEX, CXCR5, LTBR, TSFM, GALC, TRAF3, STAT3, TNFSF14, IFI30, CD40, and CYP24A1) by targeted resequencing in an Iberian population of 524 MS cases and 546 healthy controls. Four rare variants-enriched regions within CYP24A1, FCRL1, RGS1, and TRAF3 were identified as significantly associated with MS. Functional studies revealed significantly decreased regulator of G protein signaling 1 (RGS1) gene expression levels in peripheral blood mononuclear cells from MS patients with RGS1 rare variants compared to noncarriers, whereas no significant differences in gene expression were observed for CYP24A1, FCRL1, and TRAF3 between rare variants carriers and noncarriers. Immunophenotyping showed significant decrease in RGS1 expression in peripheral blood B lymphocytes from MS patients with RGS1 rare variants relative to noncarriers. Lastly, peripheral blood mononuclear cell from MS patients carrying RGS1 rare variants showed significantly lower induction of RGS1 gene expression by interferon-β compared to MS patients lacking RGS1 variants. The presence of rare variants in RGS1 reinforce the ideas of high genetic heterogeneity and a role of rare variants in MS pathogenesis.

Neurofilament light chain levels in pregnant multiple sclerosis patients: a prospective cohort study

BACKGROUND AND PURPOSE

Neurofilament light chain is a cytoskeletal protein of neurons. Its levels are increasingly recognized as measures of neuroaxonal damage. The aim of this study was to explore serum neurofilament light chain (sNfL) levels in multiple sclerosis (MS) patients and healthy controls during pregnancy and puerperium.

METHODS

This was a prospective, longitudinal, single-center study. sNfL concentration was assessed using a highly sensitive single-molecule array during pregnancy and in puerperium, in a cohort of 39 pregnant patients with relapsing multiple sclerosis (P-MS). Twenty-one healthy pregnant women (HPW) served as a control group. Eight P-MS suffered relapses during pregnancy (P-MS-R) in the first or second trimesters.

RESULTS

No differences in pregnancy and delivery data were observed between P-MS and HPW. P-MS showed higher sNfL values than HPW in the first trimester, independently of the presence (P = 0.002) or not (P = 0.02) of relapses during pregnancy. However, in the third trimester, only P-MS-R showed higher sNfL values than HPW (P = 0.001). These differences extended to the puerperium, where P-MS-R showed higher sNfL values than those with no relapses during gestation (P = 0.02).

CONCLUSION

These data strongly suggest that sNfL levels reflect MS activity during pregnancy. Additionally, the absence of relapses during pregnancy may have a beneficial effect on neurodegeneration during puerperium.

Teriflunomide induces a tolerogenic bias in blood immune cells of MS patients

Objectives

Teriflunomide, a disease‐modifying treatment approved for multiple sclerosis (MS), inhibits reversibly dihydroorotate dehydrogenase, an enzyme involved in de novo pyrimidine biosynthesis and down‐regulates proliferation of activated lymphocytes. We aimed to study the impact of this drug in the lymphocyte profiles of MS patients.

Methods

Fifty‐five patients with relapsing‐remitting MS who initiated teriflunomide treatment were included in the study. We studied peripheral blood mononuclear cells obtained before and 6 months after treatment initiation and explored effector, memory, and regulatory cells by flow cytometry. Wilcoxon matched pair tests were used to assess differences between basal and 6 months after treatment results. P‐values were corrected with Bonferroni test.

Results

When explored T and B cell subsets, we observed a decrease in the percentages of terminally differentiated CD4+ T cells (P = 0.001) and plasmablasts (P < 0.0001) after 6 months of treatment. These results were confirmed with the total cell number. When studied immunomodulatory cells, we observed a clear increase of monocytes expressing programmed death‐ligand 1 (PD‐L1) (P = 0.005), which correlated negatively with all effector CD8+ T cell subsets. We also observed an increase in the percentage of CD8+ T cells (P = 0.028) and monocytes (P = 0.04) producing IL‐10.

Conclusions

Teriflunomide induces a specific reduction in effector T and B cells that have shown to play a role in MS course and an increase in immunomodulatory cells. Particularly, this drug induces the expression of PD‐L1, a molecule involved in tolerance to autoantigens, which can contribute to inhibit the abnormal immune response taking place in MS.

Clinical usefulness of prognostic biomarkers in optic neuritis

BACKGROUND AND PURPOSE

Different biological and radiological biomarkers predict clinical conversion to multiple sclerosis (MS) after a clinically isolated syndrome (CIS). The aim was to explore their role in predicting the outcome of patients with optic neuritis (ON), a CIS considered to have a benign prognosis.

METHODS

Sixty-eight consecutive ON patients were followed prospectively. Magnetic resonance imaging (MRI) and cerebrospinal fluid studies including oligoclonal immunoglobulin G (IgG) bands (OCGBs), lipid-specific oligoclonal IgM bands (LS-OCMBs) and neurofilament light chain quantification were performed at disease onset. Conversion to clinically definite MS (CDMS) was monitored.

RESULTS

The mean time of follow-up of our series was 46.4 months. Twenty-five patients (36.7%) developed CDMS during follow-up. Neurofilament light chain levels did not predict clinical conversion. By contrast, an abnormal MRI increased the risk of CDMS [hazard ratio (HR) 12.5, P = 0.013]. The clearest association was found in patients with more than three T2 lesions. OCGBs also predicted the onset of CDMS (HR 21.3, P = 0.003) and LS-OCMBs were associated with a shorter time to CDMS (HR = 116.6, P < 0.001).

CONCLUSIONS

Magnetic resonance imaging and OCGBs predicted conversion to CDMS after an ON episode. In addition, LS-OCMBs identified the ON patients more likely to develop MS early. These results, applicable to the everyday clinical setting, may be of interest for therapeutic decisions.