Background and purpose: Information regarding multiple sclerosis (MS) patients with the 2019 novel coronavirus disease (COVID‐19) is scarce. The study objective was to describe the incidence and characteristics of MS patients with COVID‐19, to identify susceptibility and severity risk factors and to assess the proportion of positive severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) serologies according to disease‐modifying treatments.Methods: This was a retrospective study of an MS cohort analysing data collected between February and May 2020. Cases were identified through an email survey and clinical visits. The relationship of demographic and MS characteristics with COVID‐19 and of the disease‐modifying treatments with SARS‐CoV‐2 serostatus were examined.Results: Data from 48 suspected cases out of 758 valid respondents and from 45 COVID‐19 cases identified through clinical visits were collected. Incidence was 6.3%. Nineteen (20.3%) patients were hospitalized and two (2.2%) died. Multivariable models determined that age (odds ratio [OR] per 10 years 0.53, 95% confidence interval [CI] 0.34–0.85), contact with a confirmed case (OR 197.02, 95% CI 56.36–688.79), residence in Barcelona (OR 2.23, 95% CI 1.03–4.80), MS duration (OR per 5 years 1.41, 95% CI 1.09–1.83) and time on anti‐CD20 treatment (OR per 2 years 3.48, 95% CI 1.44–8.45) were independent factors for presenting COVID‐19 and age (OR per 10 years 2.71, 95% CI 1.13–6.53) for a severe COVID‐19. Out of the 79 (84.9%) with serological test, 45.6% generated antibodies, but only 17.6% of those on anti‐CD20 therapies. Lymphopaenia or immunoglobulin levels did not relate to COVID‐19.Conclusions: Multiple sclerosis patients present similar incidence, risk factors and outcomes for COVID‐19 as the general population. Patients treated with an anti‐CD20 therapy for a longer period of time might be at a higher risk of COVID‐19 and less than 20% generate an antibody response. Only age was related to severity.

Intrathecal production of kappa free light chains (KFLC) occurs in multiple sclerosis and can be measured using the KFLC index. KFLC index values can be determined more easily than oligoclonal bands (OB) detection and seem more sensitive than the immunoglobulin (Ig)G index to diagnose multiple sclerosis. We assessed the value of OB, KFLC index cut-offs 5.9, 6.6, and 10.61, and IgG index to diagnose multiple sclerosis with prospectively acquired data from a clinically isolated syndrome (CIS) inception cohort. We selected patients with sufficient data to determine OB positivity, MRI dissemination in space (DIS) and time (DIT), IgG index, and sufficient quantities of paired CSF and blood samples to determine KFLC indexes (n = 214). We used Kendall´s Tau coefficient to estimate concordance; calculated the number of additional diagnoses when adding each positive index to DIS and positive OB; performed survival analyses for OB and each index with the outcomes second attack and 2017 MRI DIS and DIT; and estimated the diagnostic properties of OB and the different indexes for the abovementioned outcomes at five years. OB were positive in 138 patients (64.5%), KFLC-5.9 in 136 (63.6%), KFLC-6.6 in 135 (63.1%), KFLC-10.61 in 126 (58.9%) and IgG index in 101 (47.2%). The highest concordance was between OB and KFLC-6.6 (τ=0.727) followed by OB and KFLC-5.9 (τ=0.716). Combining DIS plus OB or KFLC-5.9 increased the number of diagnosed patients by 11 (5.1%), with KFLC-6.6 by 10 (4.7%), with KFLC-10.61 by 9 (4.2%), and with IgG index by 3 (1.4%). Patients with positive OB or indexes reached second attack and MRI DIS and DIT faster than patients with negative results (P < 0.0001 except IgG index in second attack: P = 0.016). In multivariable Cox models [aHR (95% CI)], the risk for second attack was very similar between KFLC-5.9 [2.0 (0.9-4.3), P = 0.068] and KFLC-6.6 [2.1 (1.1-4.2), P = 0.035]. The highest risk for MRI DIS and DIT was demonstrated with KFLC-5.9 [4.9 (2.5-9.6), P < 0.0001], followed by KFLC-6.6 [3.4 (1.9-6.3), P < 0.0001]. KFLC-5.9 and KFLC-6.6 had a slightly higher diagnostic accuracy than OB for second attack (70.5, 71.1, and 67.8) and MRI DIS and DIT (85.7, 85.1, and 81.0). KFLC indexes 5.9 and 6.6 performed slightly better than OB to assess multiple sclerosis risk and in terms of diagnostic accuracy. Given the concordance between OB and these indexes, we suggest using DIS plus positive OB or positive KFLC index as a modified criterion to diagnose multiple sclerosis.

Background: Early diagnosis and treatment of multiple sclerosis (MS) is crucial to avoid future disability. The factors that influence diagnostic delay in low prevalence settings have been poorly studied. Objectives: To evaluate the factors associated with a delayed diagnosis of MS after the symptomatic onset. Methods: Clinical records of confirmed MS patients were reviewed. Diagnostic delay was calculated by subtracting the date of onset from the date of diagnosis and categorized as early and delayed, when below and above than 1 year. Logistic regression was performed to evaluate the likelihood of a delayed diagnosis according to age at first symptom, gender, type of the first symptom, progressive vs relapsing onset, diagnostic criteria prevailing at the time of symptom onset, comorbidities, and family history of MS. Results: Data of 525 (95.6%) from a cohort of 549 patients were analyzed. About 69.1% were women. The mean age was 43.2 years. About 86.3% had relapsing-remitting MS. The mean overall diagnostic delay was 3.07 years. About 45.7% of the patients had a delayed diagnosis, and it was dependent on the symptom and the diagnostic criteria prevailing at the onset. Multivariate logistic regression showed onset during the Schumacher (OR = 10.03 [95%CI 1.30–77.1], p = 0.027) and Poser (OR = 4.26 [95%CI 1.25–15.15], p = 0.021) years were associated with delayed MS diagnosis. Conclusions: MS onset before the McDonald diagnostic criteria era is associated with delayed diagnosis.

Background and Objectives Information about humoral and cellular responses to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and antibody persistence in convalescent (COVID-19) patients with multiple sclerosis (PwMS) is scarce. The objectives of this study were to investigate factors influencing humoral and cellular responses to SARS-CoV-2 and its persistence in convalescent COVID-19 PwMS. Methods This is a retrospective study of confirmed COVID-19 convalescent PwMS identified between February 2020 and May 2021 by SARS-CoV-2 antibody testing. We examined relationships between demographics, MS characteristics, disease-modifying therapy (DMT), and humoral (immunoglobulin G against spike and nucleocapsid proteins) and cellular (interferon-gamma [IFN-γ]) responses to SARS-CoV-2. Results A total of 121 (83.45%) of 145 PwMS were seropositive, and 25/42 (59.5%) presented a cellular response up to 13.1 months after COVID-19. Anti–CD20-treated patients had lower antibody titers than those under other DMTs (p < 0.001), but severe COVID-19 and a longer time from last infusion increased the likelihood of producing a humoral response. IFN-γ levels did not differ among DMT. Five of 7 (71.4%) anti-–CD20-treated seronegative patients had a cellular response. The humoral response persisted for more than 6 months in 41/56(81.13%) PwMS. In multivariate analysis, seropositivity decreased due to anti-CD20 therapy (OR 0.08 [95% CI 0.01–0.55]) and increased in males (OR 3.59 [1.02–12.68]), whereas the cellular response decreased in those with progressive disease (OR 0.04 [0.001–0.88]). No factors were associated with antibody persistence. Discussion Humoral and cellular responses to SARS-CoV-2 are present in COVID-19 convalescent PwMS up to 13.10 months after COVID-19. The humoral response decreases under anti-CD20 treatment, although the cellular response can be detected in anti–CD20-treated patients, even in the absence of antibodies.

Background: The effect of disease-modifying therapies on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccine response is unclear. Objectives: We aim to determine the immunological responses to SARS-CoV-2 in multiple sclerosis (MS) and anti-CD20-treated patients with other autoimmune diseases (AID). Methods: Humoral and cellular responses we determined before and 30-90 days after vaccination in patients with MS and anti-CD20-treated patients with other AID in two Catalan centers. Results: 457 patients were enrolled. Findings showed that humoral response decreased under anti-CD20s or sphingosine 1-phosphate receptor modulators (S1PRM) and with longer treatment duration and increased after 4.5 months from the last anti-CD20 infusion. Cellular response decreased in S1PRM-treated. Patients on anti-CD20 can present cellular responses even in the absence of antibodies. Conclusion: Anti-CD20s and S1PRM modify the immunological responses to SARS-CoV-2 vaccines.

Mitochondrial encephalopathy, lactic acidosis, and stroke-like symptoms (MELAS) and MIDD (maternally-inherited diabetes mellitus and deafness) are caused by A3243G transfer RNA mutations that affect mitochondrial function. Hearing loss and early onset diabetes mellitus constitute the main MIDD phenotype. Regarding the ophthalmologic manifestations of MIDD, we hypothesized that decreased vestibulo-ocular reflex (VOR) gain in patients with MIDD may contribute to impaired dynamic visual acuity.Neuro-ophthalmologic, neuroimaging, and neuro-otologic evaluations were performed in 2 nonrelated patients with MIDD who complained of oscillopsia with head movement. We obtained quantitative recording of the horizontal and the vertical VOR, using the video head impulse test device.In the 2 patients, we detected visual, ocular motor, and vestibular abnormalities. Decreased VOR gain in the planes of all 3 semicircular canals and impaired dynamic visual acuity was demonstrated in both cases.MIDD patients are primarily recognized by their advanced hearing loss or deafness, early onset diabetes mellitus, and lactic acidosis. Decreased vision in these patients relates primarily to peri-macular retinal atrophy. In addition, loss of vestibular function causes poor dynamic visual acuity. Both patients, in their late fifties, had evidence of progressive central and peripheral nervous system dysfunction.