Effect of alemtuzumab over sNfL and sGFAP levels in multiple sclerosis.

Introduction: Alemtuzumab is a highly effective pulsed immune reconstitution therapy for multiple sclerosis (MS). Aim: To evaluate serum neurofilament light chain (sNfL) and serum glial fibrillary acidic protein (sGFAP) in patients with relapsing-remitting MS who have been treated with Alemtuzumab over the course of 2 years. Methods: This prospective study involved MS patients treated with Alemtuzumab at a referral MS center. Both sNfL and sGFAP were analyzed at baseline and then again at 6, 12, and 24 months post-treatment using the single molecule array (SiMoA) technique. We also recruited matched healthy controls (HCs) for comparison. Results: The study included 46 patients (with a median age of 34.2 [Interquartile range (IQR), 28.7-42.3] years, 27 of which were women [58%]) and 76 HCs. No differences in demographic characteristics were observed between patients and HC. The median disease duration was 6.22 (IQR, 1.56-10.13) years. The median annualized relapse rate before treatment was 2 (IQR, 1-3). At baseline, sNfL and sGFAP levels were higher in MS patients (median of 18.8 [IQR, 10.7-52.7] pg/ml and 158.9 [IQR, 126.9-255.5] pg/ml, respectively) when compared to HC (6.11 [IQR, 2.03-8.54] pg/ml and 91.0 [72.6-109] pg/ml, respectively) (p<0.001 for both comparisons). The data indicates that 80% of patients had high (≥10 pg/ml) sNfL values at baseline. We observed a significant decrease in sNfL levels at 6 (65%, p = 0.02), 12 (70.8%, p<0.001), and 24 (78.1%, p<0.001) months. sNfL reached similar levels to HC only after 24 months of Alemtuzumab treatment. During the follow-up period, no changes were identified in the sGFAP values. Conclusion: Alemtuzumab leads to the normalization of sNfL values in MS patients after 2 years of treatment, with no apparent effect on sGFAP values.

Patients with multiple sclerosis who develop immunogenicity to interferon-beta have distinct transcriptomic and proteomic signatures prior to treatment which are associated with disease severity.

Anti-drug antibodies (ADA) reduce the efficacy of immunotherapies in multiple sclerosis (MS) and are associated with increased disease progression risk. Blood biomarkers predicting immunogenicity to biopharmaceuticals represent an unmet clinical need. Patients with relapsing remitting (RR)MS were recruited before (baseline), three, and 12 (M12) months after commencing interferon-beta treatment. Neutralising ADA-status was determined at M12, and patients were stratified at baseline according to their M12 ADA-status (ADA-positive/ADA-negative). Patients stratified as ADA-positive were characterised by an early dampened response to interferon-beta (prior to serum ADA detection) and distinct proinflammatory transcriptomic/proteomic peripheral blood signatures enriched for 'immune response activation' including phosphoinositide 3-kinase-γ and NFκB-signalling pathways both at baseline and throughout the treatment course, compared to ADA-negative patients. These immunogenicity-associated proinflammatory signatures significantly overlapped with signatures of MS disease severity. Thus, whole blood molecular profiling is a promising tool for prediction of ADA-development in RRMS and could provide insight into mechanisms of immunogenicity.

Serum Concentrations of Chemokines CCL20, CXCL8 and CXCL10 in Relapsing-Remitting Multiple Sclerosis and Their Association with Presence of Antibodies against Epstein-Barr Virus.

Epstein-Barr virus (EBV) infection and various chemokines, including CCL20, CXCL8 and CXCL10 are considered to participate in the pathogenesis of multiple sclerosis (MS), and several studies point to a direct regulatory effect of EBV on the expression of these chemokines. In our study we hypothesized that serum concentrations of CCL20, CXCL8 and CXCL0 are induced in patients with relapsing-remitting MS (RRMS) in comparison to healthy individuals, and that they are associated with EBV infection. Serum concentrations of CXCL8 and CXCL10 were lower in RRMS patients in relapse in comparison to healthy controls. Although potential effects of corticosteroid therapy introduced in a subgroup of RRMS patients prior to sampling were excluded by subgroup comparison, this possibility has to be considered while interpreting the results. We found an inverse association between serum concentrations of CXCL8 and anti-Epstein-Barr Virus Nuclear Antigen (EBNA) IgG and decreased expression of CXCL8 in peripheral blood mononuclear cells (PBMC) in relapse compared to remission. Lower serum concentrations of CXCL8 and CXCL10 in RRMS patients and decreased peripheral production of CXCL8 in relapse may indicate compensatory anti-inflammatory counter-regulation in MS.

A pilot study of monocytes in relapsing remitting multiple sclerosis: Correlation with disease activity.

Background: Numerous immune cells are involved in developing multiple sclerosis (MS). Monocytes are believed to be the first to enter the brain and initiate inflammation. The role of monocyte subtypes in MS needs to be better understood. Objective: The current study aims to investigate the presence of different subsets of monocytes in relapsing-remitting MS (RRMS) Egyptian patients and their correlation with disease activity. Methods: This study included 44 RRMS patients (22 patients in relapse, 22 patients in remission), diagnosed according to the 2017 MacDonalds criteria, and 44 matched healthy controls. Personal and medical histories were taken from the patients, and the Expanded Disability Status Scale (EDSS) was used to evaluate the degree of impairment. Characterization of peripheral blood monocyte subsets was done by flow cytometry for all participants. Results: The percentage of classical, intermediate, and non-classical monocyte subsets showed a significant increase in RRMS patients than controls with p-values of 0.029, 0.049, and 0.043, respectively. In the RRMS patients, there were no statistically significant correlations (p-values >0.05) between the EDSS scores, the duration of disease, and number of relapses in the past year and the percentages of the various monocyte subsets. Furthermore, there were no significant differences in the percentage of each monocyte subset between RRMS patients in remission and those experiencing a relapse (p-values >0.05). However, patients with evidence of activity in magnetic resonance imaging (MRI) had a significantly high percentage of non-classical monocytes with a p-value of 0.002. Conclusion: In RRMS patients, the three monocyte subsets (classical, non-classical and intermediate) increase significantly regardless of the disease activity. This increase denotes the vital role of monocytes and innate immunity in MS pathology, especially the non-classical monocyte subset. These findings suggest that monocytes might be a promising MS therapeutic target.

Immunologic analysis of CSF in patients with de novo diagnosed RRMS. The role of chemokines in the early phase of the disease.

OBJECTIVES: Multiple sclerosis (MS) is a chronic CNS autoimmune disease characterized by demyelination and neurodegeneration. Chemokines regulate leukocyte migration and inflammation in MS. In the present study, we evaluated selected chemokine levels in the cerebrospinal fluid of patients with multiple sclerosis diagnosed de novo compared to healthy controls. METHODS: We measured EOTAXIN, IP-10, MCP-1, MIP-1a, MIP-1b and RANTES in the cerebrospinal fluid of 118 patients with de novo RRMS and 112 controls, analyzing correlations with time from symptom onset to diagnosis and changes in MRI. RESULTS: Higher levels of EOTAXIN, IP-10, MIP-1B and RANTES, and lower MCP-1 were observed in MS patients compared to controls. MIP-1A did not show statistical significance. EOTAXIN and IP-10 concentrations increased with time. RANTES concentration correlated positively with T2 changes in MRI of the cervical spine, and EOTAXIN concentration correlated negatively with gadolinium (Gd+) changes in the cervical spine. There was no correlation with changes in the thoracic spine or brain. CONCLUSIONS: Chemokines play a significant role in the early phase of MS by influencing inflammatory activity. They may represent potential therapeutic targets for the treatment of this disease.

[The role of dopamine receptors in the modulation of mononuclear phagocytes in multiple sclerosis]. / Rol' retseptorov dofamina v modulyatsii mononuklearnykh fagotsitov pri rasseyannom skleroze.

OBJECTIVE: To investigate the role of dopamine receptor D1DR and D2DR in the production of cytokines interleukin-6 (IL-6) and IL-1ß by monocytes and macrophages in patients with relapsing-remitting multiple sclerosis (MS). MATERIAL AND METHODS: Ten patients with relapsing-remitting MS and 10 healthy subjects were examined. The level of IL-6 and IL-1ß production was assessed in culture supernatants obtained from CD14+ monocytes or macrophages stimulated with interferon-γ (IFN-γ) and lipopolysaccharide (LPS). To study the role of dopamine receptors in the regulation of CD14+ monocytes or macrophages, samples of cells were incubated in the presence of specific D1DR or D2DR antagonists, after which IFN-γ/LPS were added to the cultures. Levels of cytokines in culture supernatants were measured by enzyme-linked immunosorbent assay. RESULTS: The production of IL-6 and IL-1ß by CD14+ monocytes and macrophages was comparable between the groups. Blockade of D1DR suppressed cytokine production by CD14+ monocytes and macrophages in both groups. In contrast, blockade of D2DR increased the production of cytokines by CD14+ monocytes and did not affect cytokine production by macrophages in both groups. CONCLUSIONS: Targeting of dopaminergic receptors could be considered as an additional mechanism of immunomodulation in MS with both pro- and anti-inflammatory effects on cells of the innate immune system.

Case report: tumefactive demyelinating lesions after the second cycle of alemtuzumab in multiple sclerosis; immune cell profile and biomarkers.

Objective: We present a case of multiple tumefactive demyelinating lesions (TDLs) emerging 24 months after the second cycle of alemtuzumab treatment. Methods: A woman with relapsing-remitting multiple sclerosis (MS) discontinued fingolimod treatment due to gestational desire, which resulted in a severe disease exacerbation. Alemtuzumab was initiated, accompanied by regular clinical, radiological, and immunological monitoring. Results: She relapsed prior to the second cycle, exhibiting 12 T1Gd+ lesions, and peripheral blood showed an increase in B-cells and a decrease in T-cells. At 24 months following the second cycle, she developed cognitive impairment and multiple T1Gd+ lesions, including TDLs, were evident on the brain MRI. We found not only an increase in B-cells but also in Th1 central memory cells. Th1/Th17 cells increased 3 months before the detection of TDLs. Conclusions: TDLs can appear 24 months after the second cycle of alemtuzumab treatment in MS. The increase in Th1/Th17 cells could be a candidate biomarker for TDLs in alemtuzumab-treated MS patients.

CLADIN- CLADribine and INnate immune response in multiple sclerosis - A phase IV prospective study.

Cladribine (Mavenclad®) is an oral treatment for relapsing remitting MS (RRMS), but its mechanism of action and its effects on innate immune responses in unknown. This study is a prospective Phase IV study of 41 patients with RRMS, and aims to investigate the mechanism of action of cladribine on peripheral monocytes, and its impact on the P2X7 receptor. There was a significant reduction in monocyte count in vivo at week 1 post cladribine administration, and the subset of cells being most impacted were the CD14lo CD16+ 'non-classical' monocytes. Of the 14 cytokines measured in serum, CCL2 levels increased at week 1. In vitro, cladrabine induced a reduction in P2X7R pore as well as channel activity. This study demonstrates a novel mechanism of action for cladribine. It calls for studying potential benefits of cladribine in progressive forms of MS and other neurodegenerative diseases where innate immune related inflammation is implicated in disease pathogenesis.

Hyper-reflective foci changes in RRMS under natalizumab therapy.

Introduction: Microglia (MG) is suggested to play an immunopathological role of in Multiple Sclerosis (MS). Since hyper-reflective foci (HRF) might mark MG activation, in vivo analysis by Optic Coherence Tomography (OCT) in MS patients under disease modifying therapies may help to clarify MS immunopathology as well as drug's mechanism of intrathecal action. Objective: To analyze HRF in patients treated with Natalizumab (NTZ), a high efficacy therapy for MS. Materials and methods: The effect of NTZ on the retina of 36 Relapsing-Remitting MS patients was investigated in a prospective, single-center study. OCT was performed immediately before the first infusion and then between infusion 3 and 4, infusion 6 and 7, infusion 11 and 13. Peripapillary and macular scans were acquired, evaluating peripapillary RNFL thickness, macular volumes (vertical scans), and HRF count (horizontal scan) in Ganglion Cell Layer (GCL), Inner Plexiform Layer (IPL) and Inner Nuclear Layer (INL). Clinical examination was performed every six months. Results: HRF count significantly increased under NTZ therapy (p<0.001) in both GCL (18.85 ± 6.93 at baseline, 28.24 ± 9.55 after 12 months) and IPL (25.73 ± 7.03 at baseline, 33.21 ± 8.50 after 12 months) but remained stable in INL (33.65 ± 7.76 at baseline, 36.06 ± 6.86 after 12 months, p=0.87), while no relevant modification of pRNFL and macular volumes were observed during the study. EDSS remained stable and no clinical relapse was observed between month 6 and 12. Conclusion: In RRMS NTZ affects HRF count in GCL and IPL, but not in INL, suggesting that NTZ does not impact on some aspects of MS immunopathology.

20S constitutive proteasome, 20S immunoproteasome, and cathepsin S are high-sensitivity and independent markers of immunological activity in relapsing-remitting type of multiple sclerosis.

Research on the markers of autoimmune response in multiple sclerosis (MS) is still of great importance. The aim of our study was the evaluation of plasma 20S constitutive proteasome, 20S immunoproteasome, and cathepsin S concentrations as potential biomarkers of a relapsing-remitting type of MS (RRMS). Surface plasmon resonance imaging (SPRI) biosensors were used for the evaluation of protein concentrations. Plasma 20S constitutive proteasome, 20S immunoproteasome, and cathepsin S concentrations were significantly higher in RRMS patients compared to the control group. All three parameters were characterized by excellent usefulness in differentiating MS patients from healthy individuals (AUC equal to or close to 1.000). The plasma concentration of analyzed parameters was not correlated with severity of disability in the course of RRMS (EDSS value), the number of years from the first MS symptoms, the number of years from MS diagnosis, or the number of relapses within the 24-month observational period. Our study has shown that plasma concentrations of 20S constitutive proteasome, 20S immunoproteasome, and cathepsin S have promising potential in differentiating RRMS patients from healthy individuals. All of the analyzed parameters were found to be independent of the time of MS relapse and the severity of neurological symptoms. Hence, their potential as highly sensitive and independent circulating markers of RRMS suggests a stronger association with immunological activity (inflammatory processes) than with the severity of the disease.

Altered lymphocyte profiles and herpes zoster infections in patients with multiple sclerosis on natalizumab.

Cases of herpes zoster (HZ) in patients with MS on natalizumab (NTZ) have been documented. In this study, we assessed lymphocyte subsets in NTZ-treated patients with HZ compared to matched controls without HZ. Twenty unvaccinated patients developed HZ while on NTZ for an incidence rate of 12.3 per 1000 patient-years. These patients had lower CD8+% and higher CD4+:CD8+ ratios (p ⩽ 0.01) than non-HZ matched controls. Two patients with relapsing-remitting MS developed HZ twice while on NTZ. These findings underscore the importance of pre-NTZ HZ vaccination due to potential HZ risk.

Transcriptional network analysis of peripheral blood leukocyte subsets in multiple sclerosis identifies a pathogenic role for a cytotoxicity-associated gene network in myeloid cells.

Multiple sclerosis (MS) is an autoimmune disease of the central nervous system affecting predominantly adults. It is a complex disease associated with both environmental and genetic risk factors. Although over 230 risk single-nucleotide polymorphisms have been associated with MS, all are common human variants. The mechanisms by which they increase the risk of MS, however, remain elusive. We hypothesized that a complex genetic phenotype such as MS could be driven by coordinated expression of genes controlled by transcriptional regulatory networks. We, therefore, constructed a gene coexpression network from microarray expression analyses of five purified peripheral blood leukocyte subsets of 76 patients with relapsing remitting MS and 104 healthy controls. These analyses identified a major network (or module) of expressed genes associated with MS that play key roles in cell-mediated cytotoxicity which was downregulated in monocytes of patients with MS. Manipulation of the module gene expression was achieved in vitro through small interfering RNA gene knockdown of identified drivers. In a mouse model, network gene knockdown modulated the autoimmune inflammatory MS model disease-experimental autoimmune encephalomyelitis. This research implicates a cytotoxicity-associated gene network in myeloid cells in the pathogenesis of MS.

A two-years real-word study with fingolimod: early predictors of efficacy and an association between EBNA-1 IgG titers and multiple sclerosis progression.

Background: Although fingolimod, a sphingosine 1-phosphate receptor agonist, has shown to be an effective treatment reducing relapse rate and also slowing down the disability progression in relapsing-remitting multiple sclerosis (RRMS) patients, it is important to quickly identify those suboptimal responders. Objective: The main objective was to assess different clinical, radiological, genetic and environmental factors as possible early predictors of response in MS patients treated with fingolimod for 24 months. The secondary objective was to analyze the possible contribution of the environmental factors analyzed to the progression and activity of the disease along the 2-years of follow-up. Methods: A retrospective study with 151 patients diagnosed with MS, under fingolimod treatment for 24 months, with serum samples at initiation and six months later, and with clinical and radiological data at initiation and 24 months later, were included in the study. Clinical and radiological variables were collected to establish NEDA-3 (no evidence of disease activity: patients without relapses, disability progression and new T2 lesions or Gd+ lesions) and EDA (evidence of disease activity: patients with relapses and/or progression and/or new T2 lesions or gadolinium-positive [Gd+] lesions) conditions. Human leukocyte antigen II (HLA-II), EBNA-1 IgG and VCA IgG from Epstein-Barr virus (EBV) and antibody titers against Human herpesvirus 6A/B (HHV-6A/B) were also analyzed. Results: A total of 151 MS patients fulfilled the inclusion criteria: 27.8% was NEDA-3 (37.5% among those previously treated with high efficacy therapies >24 months). The following early predictors were statistically significantly associated with NEDA-3 condition: sex (male; p=0.002), age at baseline (older; p=0.009), relapses 2-years before fingolimod initiation ≤1 (p=0.010), and absence of Gd+ lesions at baseline (p=0.006). Regarding the possible contribution of the environmental factors included in the study to the activity or the progression of the disease, we only found that EBNA-1 IgG titers decreased in 20.0% of PIRA (progression independent from relapse activity) patients vs. 73.3% of RAW (relapse-associated worsening) patients (p=0.006; O.R. = 11.0). Conclusion: MS patients that are male, older, and with a low clinical and radiological activity at fingolimod initiation have a greater probability to reach NEDA-3 condition after two years with this therapy. An intriguing association of EBV with the progression of the disease has also been described, but it should be further study in a larger cohort to confirm these results.

Heightened Epstein-Barr virus immunity and potential cross-reactivities in multiple sclerosis.

BACKGROUND: Epstein-Barr virus (EBV) is a likely prerequisite for multiple sclerosis (MS) but the underlying mechanisms are unknown. We investigated antibody and T cell responses to EBV in persons with MS (pwMS), healthy EBV-seropositive controls (HC) and post-infectious mononucleosis (POST-IM) individuals up to 6 months after disease resolution. The ability of EBV-specific T cell responses to target antigens from the central nervous system (CNS) was also investigated. METHODS: Untreated persons with relapsing-remitting MS, POST-IM individuals and HC were, as far as possible, matched for gender, age and HLA-DRB1*15:01. EBV load was determined by qPCR, and IgG responses to key EBV antigens were determined by ELISA, immunofluorescence and Western blot, and tetanus toxoid antibody responses by multiplex bead array. EBV-specific T cell responses were determined ex vivo by intracellular cytokine staining (ICS) and cross-reactivity of in vitro-expanded responses probed against 9 novel Modified Vaccinia Ankara (MVA) viruses expressing candidate CNS autoantigens. RESULTS: EBV load in peripheral blood mononuclear cells (PBMC) was unchanged in pwMS compared to HC. Serologically, while tetanus toxoid responses were unchanged between groups, IgG responses to EBNA1 and virus capsid antigen (VCA) were significantly elevated (EBNA1 p = 0.0079, VCA p = 0.0298) but, importantly, IgG responses to EBNA2 and the EBNA3 family antigens were also more frequently detected in pwMS (EBNA2 p = 0.042 and EBNA3 p = 0.005). In ex vivo assays, T cell responses to autologous EBV-transformed B cells and to EBNA1 were largely unchanged numerically, but significantly increased IL-2 production was observed in response to certain stimuli in pwMS. EBV-specific polyclonal T cell lines from both MS and HC showed high levels of autoantigen recognition by ICS, and several neuronal proteins emerged as common targets including MOG, MBP, PLP and MOBP. DISCUSSION: Elevated serum EBV-specific antibody responses in the MS group were found to extend beyond EBNA1, suggesting a larger dysregulation of EBV-specific antibody responses than previously recognised. Differences in T cell responses to EBV were more difficult to discern, however stimulating EBV-expanded polyclonal T cell lines with 9 candidate CNS autoantigens revealed a high level of autoreactivity and indicate a far-reaching ability of the virus-induced T cell compartment to damage the CNS.

Alterations of Thymus-Derived Tregs in Multiple Sclerosis.

BACKGROUND AND OBJECTIVES: Multiple sclerosis (MS) is considered a prototypic autoimmune disease of the CNS. It is the leading cause of chronic neurologic disability in young adults. Proinflammatory B cells and autoreactive T cells both play important roles in its pathogenesis. We aimed to study alterations of regulatory T cells (Tregs), which likely also contribute to the disease, but their involvement is less clear. METHODS: By combining multiple experimental approaches, we examined the Treg compartments in 41 patients with relapsing-remitting MS and 17 healthy donors. RESULTS: Patients with MS showed a reduced frequency of CD4+ T cells and Foxp3+ Tregs and age-dependent alterations of Treg subsets. Treg suppressive function was compromised in patients, who were treated with natalizumab, while it was unaffected in untreated and anti-CD20-treated patients. The changes in natalizumab-treated patients included increased proinflammatory cytokines and an altered transcriptome in thymus-derived (t)-Tregs, but not in peripheral (p)-Tregs. DISCUSSION: Treg dysfunction in patients with MS might be related to an altered transcriptome of t-Tregs and a proinflammatory environment. Our findings contribute to a better understanding of Tregs and their subtypes in MS.

The role of dopamine in the modulation of monocyte-induced Th17- and Th1-immune response in multiple sclerosis.

Multiple sclerosis (MS) is a chronic inflammatory demyelinating disease of the central nervous system (CNS) with autoimmune mechanism of development. The investigation of neuroimmune interaction is one of the most developing directions in MS pathogenesis study. Catecholamines are direct mediators of this interaction and can be involved in the pathogenesis of MS by modulating cells of both innate and adaptive immune systems. The aim of this study was to investigate the influence of dopamine and norepinephrine on the ability of monocytes of patients with relapsing-remitting MS, to induce Th17- and Th1-immune response, which play a crucial role in the autoimmunity of the CNS. We found, that both dopamine and norepinephrine modulate the production of Th17- (IL-23, IL-1ß, and IL-6) and Th1-promoting (IL-12p70) cytokines by activated peripheral blood mononuclear cells or CD14+ monocytes in patients with MS and in healthy subjects. We also found the inhibitory effect of dopamine and norepinephrine on monocyte-induced production of IL-17 and IFN-γ by autologous CD4+ T-cells in both groups. Finally, the multidirectional role of D1- and D2-like dopaminergic receptors in the modulatory effect of dopamine on the ability of CD14+ monocytes to activate CD4+ T-cells was established, expanding the potential role of dopamine in the neuroimmune interaction.

Memory B cell-guided extended interval dosing of ocrelizumab in multiple sclerosis.

BACKGROUND: Ocrelizumab (OCR) is an anti-CD20 monoclonal antibody approved for the treatment of relapsing-remitting and primary-progressive multiple sclerosis (MS). We aimed to evaluate the effectiveness of an individualized OCR extended interval dosing (EID), after switching from standard interval dosing (SID). METHODS: This was a retrospective, observational, single-centre study including MS patients regularly followed at the Neurocenter of Southern Switzerland. After a cumulative OCR dose ⩾1200 mg, stable patients were switched to EID (OCR infusions following CD19+ 27+ memory B cell repopulation). RESULTS: A total of 128 patients were included in the study, and 113 (88.3%) were switched to EID with a median interval of 9.9 (8.8-11.8) months between infusions. No clinical relapses occurred; 2 (1.8%) patients experienced disability worsening. Three (2.7%) and 2 (1.8%) patients experienced new T2 brain and spinal lesions, respectively. There was a mild decrease in IgG and IgM concentrations during both SID and EID OCR regimens (ß = -0.23, p = 0.001 and ß = -0.07, p < 0.001, respectively). CONCLUSION: Switch to personalized dosing of OCR based on CD19+ 27+ memory B cell repopulation led to a great extension of the interval between infusions, with maintained clinical and radiological efficacy. Given the potential advantages in terms of safety and health costs, EID OCR regimens should be further investigated.

Intact natalizumab pharmacokinetics is impacted by endogenous IgG4 concentration.

BACKGROUND: Natalizumab (NAT) pharmacokinetics and pharmacodynamics are complicated by arm exchange with endogenous IgG4, resulting in a mixture of a more potent intact, bivalent form and a less potent, functionally monovalent form. Total NAT and endogenous IgG4 concentrations vary considerably across patients. This study assessed the concentration of intact NAT, and how it relates to total NAT and endogenous IgG4 levels in blood and saliva. METHODS: Paired serum and saliva samples from a small cohort of relapsing-remitting multiple sclerosis patients were measured for levels of intact NAT, total NAT, IgG and IgG4. RESULTS: Intact NAT concentration was dependent on both total NAT and endogenous IgG4 levels. Low endogenous IgG4 led to a higher ratio of intact NAT to total NAT, while the opposite was observed in subjects with high endogenous IgG4. Serum and saliva measurements show good concordance. CONCLUSIONS: Intact NAT concentration is influenced by both NAT pharmacokinetics and endogenous IgG4 levels. Patients with low IgG4 levels can have high concentrations of intact NAT even with lower levels of total NAT, which may explain cases of NAT-associated progressive multifocal leukoencephalopathy (PML) in such patients. Monitoring both forms of NAT could better guide dosing, maximizing drug efficacy and safety.

Association of B-cell activating factor gene variants with serum anti-JCV antibody positivity in male patients with multiple sclerosis under natalizumab treatment: Implications for progressive multifocal leukoencephalopathy risk stratification.

INTRODUCTION: Progressive multifocal leukoencephalopathy (PML) is a potentially life-threatening complication among Multiple Sclerosis (MS) patients under natalizumab treatment, with serum anti-JCV antibody titers being used for stratification risk. Given the critical role of interferon (IFN)/B-cell activating factor (BAFF) axis in humoral immune responses against viruses, we explored whether it is involved in the generation of serum anti-JCV antibodies among these patients. METHODS: 162 consecutive patients with relapsing-remitting MS under natalizumab treatment were included. Serum anti-JCV antibodies were measured at baseline, as well as 12 and 24 months after treatment initiation. Type I and II IFN-inducible genes and BAFF expression were quantitated in peripheral blood by qRT-PCR. Moreover, BAFF rs9514828, rs1041569, and rs9514827 gene variants were assessed by RFLP-PCR. RESULTS: While type I and II IFN inducible gene expression were not associated with anti-JCV serum titers, the latter were significantly correlated with BAFF gene expression. Of interest, the TTT haplotype of the studied BAFF variants was more frequently detected in male, but not female anti-JCV (+) MS patients compared to anti-JCV (-) counterparts at baseline, as well as at 12 months and 24 months of natalizumab treatment. Measures of clinical validity/utility for the BAFF TTT haplotype showed 88% specificity, 45%, positive predictive value, and sensitivity of 70% for the discrimination of anti-JCV (+) male MS patients after 24 months of treatment. CONCLUSIONS: Our study suggests an implication of the BAFF axis in the production of serum anti-JCV antibodies. Additionally, the BAFF TTT haplotype derived from the rs9514828, rs1041569, and rs9514827 variants may represent a novel risk factor for anti-JCV seropositivity and indirectly for PML development among male MS patients treated with natalizumab.

Effects of anti-CD20 therapy on circulating and intrathecal follicular helper T cell subsets in multiple sclerosis.

Follicular helper T (Tfh) cells and their interplay with B cells likely contribute to the pathogenesis of relapsing-remitting multiple sclerosis (RRMS). Tfh cells are enriched in cerebrospinal fluid (CSF) in RRMS, but effects of anti-CD20 therapy are unknown. We investigated Tfh cells in controls, untreated and anti-CD20-treated patients with RRMS using flow cytometry. CSF Tfh cells were increased in untreated patients. Compared to paired blood samples, CD25- Tfh cells were enriched in CSF in RRMS, but not in controls. Contrast-enhancing brain MRI lesions and IgG index correlated with CSF CD25- Tfh cell frequency in untreated patients with RRMS. Anti-CD20 therapy reduced the numbers of circulating PD1+ Tfh cells and CD25- Tfh cells, and the frequency of CSF CD25- Tfh cells. The study suggests that CD25- Tfh cells are recruited to the CSF in RRMS, associated with focal inflammation, and are reduced by anti-CD20 therapy.