If confirmed in a bigger cohort of patients, analysis of percentages of minor lymphocyte subpopulations in peripheral blood of patients with RRMS prior and after +1 month of treatment might predict clinical response to fingolimod.

Literature suggests that oxidative stress (OS) may be involved in the pathogenesis of multiple sclerosis (MS), in which the immune system is known to play a key role. However, to date, the OS in peripheral lymphocytes and its contribution to the disease remain unknown. The aim of the present study was to explore the influence of OS in peripheral lymphocytes of MS patients. To that end, a cross-sectional, observational pilot study was conducted [n = 58: 34 MS and 24 healthy subjects (control group)]. We have measured superoxide production and protein mitochondrial complex levels in peripheral blood mononuclear cells (PBMCs) isolated from MS patients and control. Lactate levels and the antioxidant capacity were determined in plasma. We adjusted the comparisons between study groups by age, sex and cell count according to case. Results demonstrated that PBMCs, specifically T cells, from MS patients exhibited significantly increased superoxide anion production compared to control group (p = 0.027 and p = 0.041, respectively). Increased superoxide production in PBMCs was maintained after the adjustment (p = 0.044). Regarding mitochondrial proteins, we observe a significant decrease in the representative protein content of the mitochondrial respiratory chain complexes I-V in PBMCs of MS patients (p = 0.002, p = 0.037, p = 0.03, p = 0.044, and p = 0.051, respectively), which was maintained for complexes I, III, and V after the adjustment (p = 0.026; p = 0.033; p = 0.033, respectively). In MS patients, a trend toward increased plasma lactate concentration was detected [8.04 mg lactate/dL (5.25, 9.49) in the control group, 11.36 mg lactate/dL (5.41, 14.81) in MS patients] that was statistically significant after the adjustment (p = 0.013). This might be indicative of compromised mitochondrial function. Finally, antioxidant capacity was also decreased in plasma from MS patients, both before (p = 0.027) and after adjusting for sex and age (p = 0.006). Our findings demonstrate that PBMCs of MS patients show impaired mitochondrial redox status and deficient antioxidant capacity. These results demonstrate for the first time the existence of mitochondrial alterations in the cells immune cells of MS patients already at the peripheral level.

Multiple sclerosis (MS) is a complex multifactorial neuropathology. Although its etiology remains unclear, it has been demonstrated that the immune system attacks myelin, leading to demyelination and axonal damage. The involvement of lipids as one of the main components of myelin sheaths in MS and other demyelinating diseases has been postulated. However, it is still a matter of debate whether specific alteration patterns exist over the disease course. Here, using a lipidomic approach, we demonstrated that, at the time of diagnosis, the cerebrospinal fluid of MS patients presented differences in 155 lipid species, 47 of which were identified. An initial hierarchical clusterization was used to classify MS patients based on the presence of 25 lipids. When a supervised method was applied in order to refine this classification, a lipidomic signature was obtained. This signature was composed of 15 molecules belonging to five different lipid families including fatty acids (FAs). An FA-targeted approach revealed differences in two members of this family: 18:3n3 and 20:0 (arachidic acid). These results reveal a CSF lipidomic signature in MS patients at the time of diagnosis that might be considered as a potential diagnostic tool.

A risk for developing progressive multifocal leukoencephalopathy is a major barrier to natalizumab use. Extended dosing intervals have been proposed as a way to maintain therapeutic efficacy and reduce progressive multifocal leukoencephalopathy incidence. This is the first reported case of progressive multifocal leukoencephalopathy in a patient using an extended dosing regimen (300 mg/6 weeks). A close clinical and imaging monitoring allowed early detection, which is a major prognostic factor. A favorable outcome was seen with a therapy comprising plasma exchange therapy, mirtazapine, mefloquine and cidofovir. Further studies will be needed to assess the potential role of extended dosing intervals to improve prognosis in patients receiving natalizumab and also to measure its impact clinically and/or radiologically.

Background: Disease-modifying therapies (DMTs) used to treat multiple sclerosis (MS) alter the immune system and therefore increase the risk of infection. There is growing concern about the impact of COVID-19 on patients with MS (pwMS), especially those treated with DMTs. Methods: This is a single-center prospective observational study based on data from the Esclerosis Múltiple y COVID-19 (EMCOVID-19) study. Demographic characteristics, MS history, laboratory data and SARS-CoV-2 serology, and symptoms of COVID-19 in pwMS treated with any DTM were extracted. The relationship among demographics, MS status, DMT, and COVID-19 was evaluated. Results: A total of 259 pwMS were included. The administration of interferon was significantly associated with the presence of SARS-CoV-2 antibodies (26.4% vs. 10.7%, p = 0.006). Although patients taking interferon were significantly older (49.1 vs. 43.5, p = 0.003), the association of interferon with the presence of SARS-CoV-2 antibodies was still significant in the multivariate analysis (OR 2.99 (1.38; 6.36), p = 0.006). Conclusions: According to our data, pwMS present a higher risk of COVID-19 infection compared with results obtained from the general population. There is no evidence of a worse COVID-19 outcome in pwMS. DMTs did not significantly change the frequency of COVID-19, except for interferon; however, these findings must be interpreted with caution given the small sample of pwMS taking each DMT.