Multiple sclerosis following SARS-CoV-2 infection

Multiple Sclerosis Onset before and after COVID-19 Vaccination: Can HLA Haplotype Be Determinant?

A few cases of multiple sclerosis (MS) onset after COVID-19 vaccination have been reported, although the evidence is insufficient to establish causality. The aim of this study is to compare cases of newly diagnosed relapsing-remitting MS before and after the outbreak of the COVID-19 pandemic and the impact of COVID-19 vaccination. Potential environmental and genetic predisposing factors were also investigated, as well as clinical patterns. This is a single-centre retrospective cohort study including all patients who presented with relapsing-remitting MS onset between January 2018 and July 2022. Data on COVID-19 vaccination administration, dose, and type were collected. HLA-DRB1 genotyping was performed in three subgroups. A total of 266 patients received a new diagnosis of relapsing-remitting MS in our centre, 143 before the COVID-19 pandemic (until and including March 2020), and 123 during the COVID-19 era (from April 2020). The mean number of new MS onset cases per year was not different before and during the COVID-19 era and neither were baseline patients' characteristics, type of onset, clinical recovery, or radiological patterns. Fourteen (11.4%) patients who subsequently received a new diagnosis of MS had a history of COVID-19 vaccination within one month before symptoms onset. Patients' characteristics, type of onset, clinical recovery, and radiological patterns did not differ from those of patients with non-vaccine-related new diagnoses of MS. The allele frequencies of HLA-DRB1*15 were 17.6% and 22.2% in patients with non-vaccine-related disease onset before and during the COVID-19 era, respectively, while no case of HLA-DRB1*15 was identified among patients with a new diagnosis of MS post-COVID-19 vaccine. In contrast, HLA-DRB1*08+ or HLA-DRB1*10+ MS patients were present only in this subgroup. Although a causal link between COVID-19 vaccination and relapsing-remitting MS cannot be detected, it is interesting to note and speculate about the peculiarities and heterogeneities underlying disease mechanisms of MS, where the interactions of genetics and the environment could be crucial also for the follow-up and the evaluation of therapeutic options.

COVID-19 neuroimaging update: pathophysiology, acute findings, and post-acute developments

COVID-19 has prominent effects on the nervous system with important manifestations on neuroimaging. In this review, we discuss the neuroimaging appearance of acute COVID-19 that became evident during the early stages of the pandemic. We highlight the underlying pathophysiology mediating nervous system effects and neuroimaging appearances including systemic inflammatory response such as cytokine storm, coagulopathy, and para/post-infections immune mediated phenomena. We also discuss the nervous system manifestations of COVID-19 and the role of imaging as the pandemic has evolved over time, including related to the development of vaccines and the emergence of post-acute sequalae such as long COVID.

Visual evoked potential abnormalities in patients with COVID-19

OBJECTIVE

It has been suggested that diseases that may cause visual evoked potential abnormality, such as optic neuritis, may be associated with the coronavirus disease 2019. This study aimed to find out whether there are visual evoked potential abnormalities in coronavirus disease 2019 patients using pattern reversal visual evoked potential and flash visual evoked potential.

METHODS

Patients with a history of coronavirus disease 2019 (coronavirus disease 2019 patients) and controls were included in this prospective case-control study. This study was conducted in the Clinical Neurophysiology Laboratory of Adana City Training and Research Hospital. Individuals without visual impairment were included. Coronavirus disease 2019 patients were required to have clinical features consistent with previous acute infection and a positive nose swab polymerase chain reaction test. Visual evoked potential was applied to coronavirus disease 2019 patients between July 2020 and July 2021. Controls consisted of patients without a history of chronic disease who underwent a visual evoked potential study between June 2017 and June 2018 due to headache or dizziness. Pattern reversal visual evoked potential and flash visual evoked potential were applied to all participants. N75, P100, and N135 waves obtained from pattern reversal visual evoked potential and P1, N1, P2, N2, P3, and N3 waves obtained from flash visual evoked potential were analyzed.

RESULTS

A total of 44 coronavirus disease 2019 patients and 40 controls were included in the study. Age and gender were not different between the two groups. Pattern reversal visual evoked potential parameters were not different between the two groups. Right P2 latency was 114.4±21.1 and 105.5±14.7 ms in coronavirus disease 2019 patients and controls, respectively (p=0.031). Patients with P100 and P2 wave abnormalities were 6 (13.6%) and 13 (29.6%), respectively.

CONCLUSION

This study showed that there may be visual evoked potential abnormalities in coronavirus disease 2019 patients.

Outcomes of COVID-19 disease and its effect on disability in patients with multiple sclerosis and other allied demyelinating disorders

BACKGROUND

Coronavirus disease of 2019 (COVID-19) pandemic has posed challenges for clinicians with respect to questions regarding vulnerability of patients with chronic autoimmune diseases like Multiple Sclerosis (MS) and other demyelinating central nervous system (CNS) disorders.

OBJECTIVES

We assessed outcomes of COVID-19 disease among patients with CNS demyelinating disorders and its effect on neurological disability.

METHODS

This was an electronic survey in which a structured questionnaire was distributed to patients registered with neuroimmunology and MS clinics at All India Institute of Medical Sciences, New Delhi, India. The patients were enquired for their primary disease characteristics, occurrence and course of COVID-19 infection and its effect on their underlying disability, if any. Patients visiting clinics in person were also assessed and data from both sources was pooled.

RESULTS

61 patients with these disorders reported to have contracted COVID-19 infection (mean age- 35.60+10.28 years, females-75.4%, MS-85.2%). None of them suffered from severe/critical COVID-19 despite heterogeneity of disease modifying therapy (DMT) use. DMTs were not associated with increased risk of lymphopenia during illness. 3.3% patients reported fresh relapse and 16.4% had worsening of their neurological disability during/after COVID-19 infection with half of them not attaining their baseline status on follow-up. None of demographic or biochemical parameters were predictive of this neurological worsening.

CONCLUSION

Our study suggests that patients with these disorders might not be at heightened risk of severe COVID-19. Adverse effect of COVID-19 infection on neurological disability needs further exploration.

Nervous system-related tropism of SARS-CoV-2 and autoimmunity in COVID-19 infection

The effects of SARS-CoV-2 in COVID-19 on the nervous system are incompletely understood. SARS-CoV-2 can infect endothelial cells, neurons, astrocytes, and oligodendrocytes with consequences for the host. There are indications that infection of these CNS-resident cells may result in long-term effects, including emergence of neurodegenerative diseases. Indirect effects of infection with SARS-CoV-2 relate to the induction of autoimmune disease involving molecular mimicry or/and bystander activation of T- and B cells and emergence of autoantibodies against various self-antigens. Data obtained in preclinical models of coronavirus-induced disease gives important clues for the understanding of nervous system-related assault of SARS-CoV-2. The pathophysiology of long-COVID syndrome and post-COVID syndrome in which autoimmunity and immune dysregulation might be the driving forces are still incompletely understood. A better understanding of nervous-system-related immunity in COVID-19 might support the development of therapeutic approaches. In this review, the current understanding of SARS-CoV-2 tropism for the nervous system, the associated immune responses, and diseases are summarized. The data indicates that there is viral tropism of SARS-CoV-2 in the nervous system resulting in various disease conditions. Prevention of SARS-CoV-2 infection by means of vaccination is currently the best strategy for the prevention of subsequent tissue damage involving the nervous system.

Transgenic mouse models support a protective role of type I IFN response in SARS-CoV-2 infection-related lung immunopathology and neuroinvasion

Type I interferon (IFN-I) response is the first line of host defense against invading viruses. In the absence of definite mouse models, the role of IFN-I in SARS-CoV-2 infection remains perplexing. Here, we develop two mouse models, one with constitutively high IFN-I response (hACE2; Irgm1-/-) and the other with dampened IFN-I response (hACE2; Ifnar1-/-), to comprehend the role of IFN-I response. We report that hACE2; Irgm1-/- mice are resistant to lethal SARS-CoV-2 infection. In contrast, a severe SARS-CoV-2 infection along with immune cell infiltration, cytokine storm, and enhanced pathology is observed in the lungs and brain of hACE2; Ifnar1-/- mice. The hACE2; Irgm1-/-Ifnar1-/- double-knockout mice display loss of the protective phenotype observed in hACE2; Irgm1-/- mice, suggesting that heightened IFN-I response accounts for the observed immunity. Taking the results together, we demonstrate that IFN-I protects from lethal SARS-CoV-2 infection, and Irgm1 (IRGM) could be an excellent therapeutic target against SARS-CoV-2.

Prevalence of serum MOG antibody and AQP4 antibody in optic neuritis after SARS-CoV-2 infection

Purpose

To evaluate the prevalence of serum myelin oligodendrocyte glycoprotein antibody (MOG-Ab) and aquaporin-4 antibody (AQP4-Ab) in optic neuritis (ON) patients after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection by cell-based indirect immunofluorescence assay (CBA).

Methods

In this prospective case series study, 35 patients clinically diagnosed as ON and laboratory-confirmed SARS-CoV-2 infection from 8 December 2022 to 8 February 2023 were included. All patients' clinical and laboratory data were collected and analyzed.

Results

The mean age of the 35 patients (46 eyes) was 38.2 years (ranging from 6 to 69 years), and 17 cases were female patients. Thirty-three and two cases showed positive SARS-CoV-2 RNA test results before or shortly after ON onset, respectively. ON occurred unilaterally in 24 cases and bilaterally in 11 cases. Ophthalmic examination revealed swollen optic disc in 37 eyes, normal optic disc in 6 eyes, and temporally or wholly paled optic disc in 3 eyes. CBA revealed seropositive MOG-Ab in 10 cases and AQP4-Ab in 2 cases, respectively, of which 2 AQP4-Ab-seropositive cases and 1 MOG-Ab-seropositive case had a past medical history of ON. Most ON patients showed a rapid and dramatic response to pulse steroid therapy. The median of BCVA at the onset and at the last follow-up was 20/500 (ranging from light perception to 20/20) and 20/67 (ranging from counting fingers to 20/20), respectively.

Conclusion

Serum MOG-Ab and AQP4-Ab were detected in 28.6% (10/35) and 5.7% (2/35) ON cases after SARS-CoV-2 infection. SARS-CoV-2 infection may trigger an onset or a relapse of ON, as well as the production of MOG-Ab.

Optimisation of SARS-CoV-2 peptide stimulation and measurement of cytokine output by intracellular flow cytometry and bio-plex analysis

Our study was conducted to optimise a peptide stimulation and an intracellular cytokine staining protocol, alongside Bio-Plex supernatant analysis, for use in patients who had previously contracted SARS-CoV-2 or received vaccination against this virus in a clinical laboratory setting. Peripheral Blood Mononuclear Cell extraction and cryopreservation allowed for cells to be stored long term and enhanced logistical processing of samples. Viability and functionality of cells were analysed by flow cytometric methodology using viability staining monoclonal antibodies conjugated to fluorochromes. Antibiotics and Benzonase Nuclease did not impact lymphocyte viability and so cell culture conditions were optimised in terms of retaining viability and functionality. Optimisation of peptide stimulation with Influenza and SARS-CoV-2 peptide pools was conducted through stimulation experiments assessing peptide concentration, peptide stimulation time and enrichment studies to increase precursor frequency. Cytokine output was measured by flow cytometry and Bio-Plex methodologies, with positive cytokine readings predominantly detected in the cell culture supernatant. Analysis of both intracellular and extracellular compartments allowed for detection of cytokines and established the retained cellular functionality post cryopreservation. These results also indicated that our peptide stimulation method can generate antigen-specific T lymphocytes upon exposure to SARS-CoV-2 peptide pools. Moreover, the measurement of specific cytokines could be applied to an array of conditions, such as chronic inflammatory diseases, but to also offer an alternative method of measuring vaccine responses. This platform is easily adaptable and can remain relevant alongside changing vaccine composition, thus ensuring its applicability to future vaccination programmes.

Changes in Reaction Time, Balance and Neuroplasticity after Exercise with a Face Mask in Male Adults with Mild COVID-19 Symptoms

This study compared physiological, perceptual and neuroprotective hormone and metabolite responses and changes in coordination as an effect of aerobic exercise with and without a face mask in people with mild symptoms of COVID-19. Forty men took part in this study. Half declared mild symptoms of SARS-CoV-2 infection in the 6 months before the study (Declared) and the other half did not (Non-declared). In a random order, with a 7-day interval, they performed a 30-min walk on a treadmill at a speed of 6 km/h wearing a surgical face mask (Masked) and without it (Unmasked). The heart rate, heart rate variability, oxygen saturation, lactate concentration and rate of perceived exertion were recorded. The reaction time and balance were measured before and after the exercise. The concentrations of brain-derived neurotrophic factor, testosterone, cortisol, epinephrine and antibodies in the blood serum were determined. Physiological and perceptual responses, reaction times, and balance did not differ between the tested conditions. Three-way RM-ANOVA with post hoc Bonferroni analysis revealed lower post-exercise cortisol concentrations in the Masked and Unmasked conditions in both groups (p ≤ 0.001). Asymptomatic infection with this virus is prevalent, and mild COVID-19 causes similar responses to aerobic exercise with a surgical face mask and does not lead to impaired coordination.

Central nervous system complications in SARS-CoV-2-infected patients

OBJECTIVE

To investigate the clinical manifestations, treatment and prognosis of COVID-19-associated central nervous system (CNS) complications.

METHODS

In this single-centre observation study, we recruited patients with COVID-19-associated CNS complications at the neurology inpatient department of the Eighth Affiliated Hospital, Sun Yat-Sen University (Futian, Shenzhen) from Dec 2022 to Feb 2023. Patients were analysed for demographics, clinical manifestations, cerebrospinal fluid properties, electroencephalographic features, neuroimaging characteristics, and treatment outcome. All patients were followed-up at 1 and 2 months after discharge until Apr 2023.

RESULTS

Of the 12 patients with COVID-19-associated CNS complications, the CNS symptoms occur between 0 days and 4 weeks after SARS-CoV-2 infection. The most common CNS symptoms were memory deficits (4/12, 33%), Unresponsiveness (4/12, 33%), mental and behavioural disorders (4/12, 33%). Seven of 12 cases can be categorized as probable SARS-CoV-2 encephalitis, and 5 cases can be described as brainstem encephalitis, acute disseminated encephalomyelitis, optic neuritis, multiple sclerosis or tremor probably associated with SARS-CoV-2 infection. Six patients received antiviral therapy, and 11 patients received glucocorticoid therapy, of which 3 patients received human immunoglobulin synchronously. Nine patients recovered well, two patients had residual neurological dysfunction, and one patient passed away from complications associated with tumor.

CONCLUSION

In this observational study, we found that the inflammatory or immune-related complications were relatively common manifestations of COVID-19-associated CNS complications, including different phenotypes of encephalitis and CNS inflammatory demyelinating diseases. Most patients recovered well, but a few patients had significant neurological dysfunctions remaining.

Impaired immune response against SARS-CoV-2 infection is the major factor indirectly altering reproductive function in COVID-19 patients: a narrative review

Coronavirus disease 2019 (COVID-19) is an infectious disease affecting multiple systems and organs, including the reproductive system. SARS-CoV-2, the virus that causes COVID-19, can damage reproductive organs through direct (angiotensin converting enzyme-2, ACE-2) and indirect mechanisms. The immune system plays an essential role in the homeostasis and function of the male and female reproductive systems. Therefore, an altered immune response related to infectious and inflammatory diseases can affect reproductive function and fertility in both males and females. This narrative review discussed the dysregulation of innate and adaptive systems induced by SARS-CoV-2 infection. We reviewed the evidence showing that this altered immune response in COVID-19 patients is the major indirect mechanism leading to adverse reproduction outcomes in these patients. We summarized studies reporting the long-term effect of SARS-CoV-2 infection on women's reproductive function and proposed the chronic inflammation and chronic autoimmunity characterizing long COVID as potential underlying mechanisms. Further studies are needed to clarify the role of autoimmunity and chronic inflammation (long COVID) in altered female reproduction function in COVID-19.

Molecular mimicry and autoimmunity in the time of COVID-19

Infectious diseases are commonly implicated as potential initiators of autoimmune diseases (ADs) and represent the most commonly known factor in the development of autoimmunity in susceptible individuals. Epidemiological data and animal studies on multiple ADs suggest that molecular mimicry is one of the likely mechanisms for the loss of peripheral tolerance and the development of clinical disease. Besides molecular mimicry, other mechanisms such as defects in central tolerance, nonspecific bystander activation, epitope-determinant spreading, and/or constant antigenic stimuli, may also contribute for breach of tolerance and to the development of ADs. Linear peptide homology is not the only mechanism by which molecular mimicry is established. Peptide modeling (i.e., 3D structure), molecular docking analyses, and affinity estimation for HLAs are emerging as critical strategies when studying the links of molecular mimicry in the development of autoimmunity. In the current pandemic, several reports have confirmed an influence of SARS-CoV-2 on subsequent autoimmunity. Bioinformatic and experimental evidence support the potential role of molecular mimicry. Peptide dimensional analysis requires more research and will be increasingly important for designing and distributing vaccines and better understanding the role of environmental factors related to autoimmunity.

Risk of autoimmune diseases following COVID-19 and the potential protective effect from vaccination: a population-based cohort study

Background

Case reports suggest that SARS-CoV-2 infection could lead to immune dysregulation and trigger autoimmunity while COVID-19 vaccination is effective against severe COVID-19 outcomes. We aim to examine the association between COVID-19 and development of autoimmune diseases (ADs), and the potential protective effect of COVID-19 vaccination on such an association.

Methods

A retrospective cohort study was conducted in Hong Kong between 1 April 2020 and 15 November 2022. COVID-19 was confirmed by positive polymerase chain reaction or rapid antigen test. Cox proportional hazard regression with inverse probability of treatment weighting was applied to estimate the risk of incident ADs following COVID-19. COVID-19 vaccinated population was compared against COVID-19 unvaccinated population to examine the protective effect of COVID-19 vaccination on new ADs.

Findings

The study included 1,028,721 COVID-19 and 3,168,467 non-COVID individuals. Compared with non-COVID controls, patients with COVID-19 presented an increased risk of developing pernicious anaemia [adjusted Hazard Ratio (aHR): 1.72; 95% Confidence Interval (CI): 1.12-2.64]; spondyloarthritis [aHR: 1.32 (95% CI: 1.03-1.69)]; rheumatoid arthritis [aHR: 1.29 (95% CI: 1.09-1.54)]; other autoimmune arthritis [aHR: 1.43 (95% CI: 1.33-1.54)]; psoriasis [aHR: 1.42 (95% CI: 1.13-1.78)]; pemphigoid [aHR: 2.39 (95% CI: 1.83-3.11)]; Graves' disease [aHR: 1.30 (95% CI: 1.10-1.54)]; anti-phospholipid antibody syndrome [aHR: 2.12 (95% CI: 1.47-3.05)]; immune mediated thrombocytopenia [aHR: 2.1 (95% CI: 1.82-2.43)]; multiple sclerosis [aHR: 2.66 (95% CI: 1.17-6.05)]; vasculitis [aHR: 1.46 (95% CI: 1.04-2.04)]. Among COVID-19 patients, completion of two doses of COVID-19 vaccine shows a decreased risk of pemphigoid, Graves' disease, anti-phospholipid antibody syndrome, immune-mediated thrombocytopenia, systemic lupus erythematosus and other autoimmune arthritis.

Interpretation

Our findings suggested that COVID-19 is associated with an increased risk of developing various ADs and the risk could be attenuated by COVID-19 vaccination. Future studies investigating pathology and mechanisms would be valuable to interpreting our findings.

Funding

Supported by RGC Collaborative Research Fund (C7154-20GF).

Neurological manifestations of SARS-CoV-2: complexity, mechanism and associated disorders

BACKGROUND

Coronaviruses such as Severe Acute Respiratory Syndrome coronavirus (SARS), Middle Eastern Respiratory Syndrome (MERS) and Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) are associated with critical illnesses, including severe respiratory disorders. SARS-CoV-2 is the causative agent of the deadly COVID-19 illness, which has spread globally as a pandemic. SARS-CoV-2 may enter the human body through olfactory lobes and interact with the angiotensin-converting enzyme2 (ACE2) receptor, further facilitating cell binding and entry into the cells. Reports have shown that the virus can pass through the blood-brain barrier (BBB) and enter the central nervous system (CNS), resulting in various disorders. Cell entry by SARS-CoV-2 largely relies on TMPRSS2 and cathepsin L, which activate S protein. TMPRSS2 is found on the cell surface of respiratory, gastrointestinal and urogenital epithelium, while cathepsin-L is a part of endosomes.

AIM

The current review aims to provide information on how SARS-CoV-2 infection affects brain function.. Furthermore, CNS disorders associated with SARS-CoV-2 infection, including ischemic stroke, cerebral venous thrombosis, Guillain-Barré syndrome, multiple sclerosis, meningitis, and encephalitis, are discussed. The many probable mechanisms and paths involved in developing cerebrovascular problems in COVID patients are thoroughly detailed.

MAIN BODY

There have been reports that the SARS-CoV-2 virus can cross the blood-brain barrier (BBB) and enter the central nervous system (CNS), where it could cause a various illnesses. Patients suffering from COVID-19 experience a range of neurological complications, including sleep disorders, viral encephalitis, headaches, dysgeusia, and cognitive impairment. The presence of SARS-CoV-2 in the cerebrospinal fluid (CSF) of COVID-19 patients has been reported. Health experts also reported its presence in cortical neurons and human brain organoids. The possible mechanism of virus infiltration into the brain can be neurotropic, direct infiltration and cytokine storm-based pathways. The olfactory lobes could also be the primary pathway for the entrance of SARS-CoV-2 into the brain.

CONCLUSIONS

SARS-CoV-2 can lead to neurological complications, such as cerebrovascular manifestations, motor movement complications, and cognitive decline. COVID-19 infection can result in cerebrovascular symptoms and diseases, such as strokes and thrombosis. The virus can affect the neural system, disrupt cognitive function and cause neurological disorders. To combat the epidemic, it is crucial to repurpose drugs currently in use quickly and develop novel therapeutics.

COVID-19 infection: a possible induction factor for development of autoimmune diseases?

Following the global spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, the importance of investigation of the pathogenesis and immunological characteristics of COVID-19 became quite clear. Currently, there are reports indicating that COVID-19 is able to induce autoimmune responses. Abnormal immune reactions are a cornerstone in the pathogenicity of both conditions. Detection of autoantibodies in COVID-19 patients may suggest a link between COVID-19 and autoimmunity. In this study, we focused on the similarities and possible differences between COVID-19 and autoimmune disorders to explore the relationship between them. Comparing the pathogenicity of SARS-CoV-2 infection with autoimmune conditions revealed significant immunological properties of COVID-19 including the presence of several autoantibodies, autoimmunity-related cytokines, and cellular activities that could be useful in future clinical studies aiming at managing this pandemic.

Neurologic and Neuromuscular Sequelae of COVID-19

It is known that there can be neurologic complications related to acute infection with SARS-CoV-2, the virus that causes COVID-19. Currently, there is a growing body of evidence that postacute sequelae of SARS-CoV-2 infection can manifest as neurologic sequelae as a result of direct neuroinvasion, autoimmunity, and possibly lead to chronic neurodegenerative processes. Certain complications can be associated with worse prognosis, lower functional outcome, and higher mortality. This article provides an overview of the known pathophysiology, symptoms presentation, complications and treatment approaches of the post-acute neurologic and neuromuscular sequelae of SARS-CoV-2 infection.

The Potential Role of SARS-CoV-2 Infection and Vaccines in Multiple Sclerosis Onset and Reactivation: A Case Series and Literature Review

The recent SARS-CoV-2 pandemic and related vaccines have raised several issues. Among them, the potential role of the viral infection (COVID-19) or anti-SARS-CoV-2 vaccines as causal factors of dysimmune CNS disorders, as well as the safety and efficacy of vaccines in patients affected by such diseases and on immune-active treatments have been analyzed. The aim is to better understand the relationship between SARS-CoV-2 infection/vaccines with dysimmune CNS diseases by describing 12 cases of multiple sclerosis/myelitis onset or reactivation after exposure to SARS-CoV-2 infection/vaccines and reviewing all published case reports or case series in which MS onset or reactivation was temporally associated with either COVID-19 (8 case reports, 3 case series) or anti-SARS-CoV-2 vaccines (13 case reports, 6 case series). All the cases share a temporal association between viral/vaccine exposure and symptoms onset. This finding, together with direct or immune-based mechanisms described both during COVID-19 and MS, claims in favor of a role for SARS-CoV-2 infection/vaccines in unmasking dysimmune CNS disorders. The most common clinical presentations involve the optic nerve, brainstem and spinal cord. The preferential tropism of the virus together with the presence of some host-related genetic/immune factors might predispose to the involvement of specific CNS districts.

Neuro-Ophthalmic Visual Impairment in the Setting of COVID-19

We set out to describe in detail the afferent neuro-ophthalmological complications that have been reported in association with coronavirus disease 2019 (COVID-19) infection. We describe and elaborate on mechanisms of disease, including para-infectious inflammation, hypercoagulability, endothelial damage, and direct neurotropic viral invasion. Despite global vaccination programs, new variants of COVID-19 continue to pose an international threat, and patients with rare neuro-ophthalmic complications are likely to continue to present for care.Afferent complications from COVID-19 include homonymous visual field loss, with or without higher cortical visual syndromes, resulting from stroke, intracerebral hemorrhage, or posterior reversible leukoencephalopathy. Optic neuritis has frequently been reported, sometimes along with acute disseminated encephalomyelopathy, often in association with either myelin oligodendrocyte glycoprotein antibodies (MOG-IgG) or less commonly aquaporin-4 seropositivity or in newly diagnosed multiple sclerosis. Ischemic optic neuropathy has rarely been reported. Papilledema, resulting either from venous sinus thrombosis or idiopathic intracranial hypertension in the setting of COVID-19, has also been described.Observed afferent neuro-ophthalmic associations need to be confirmed though larger comparative studies. Meanwhile, the range of possible complications should be recognized by neurologists and ophthalmologists alike, to facilitate faster diagnosis and treatment of both COVID-19 and its neuro-ophthalmic manifestations.

Central Nervous System Neuroimmunologic Complications of COVID-19

Autoimmune disorders of the central nervous system following COVID-19 infection include multiple sclerosis (MS), neuromyelitis optica spectrum disorder, myelin oligodendrocyte glycoprotein antibody-associated disease, autoimmune encephalitis, acute disseminated encephalomyelitis, and other less common neuroimmunologic disorders. In general, these disorders are rare and likely represent postinfectious phenomena rather than direct consequences of the SARS-CoV-2 virus itself. The impact of COVID-19 infection on patients with preexisting neuroinflammatory disorders depends on both the disorder and disease-modifying therapy use. Patients with MS do not have an increased risk for severe COVID-19, though patients on anti-CD20 therapies may have worse clinical outcomes and attenuated humoral response to vaccination. Data are limited for other neuroinflammatory disorders, but known risk factors such as older age and medical comorbidities likely play a role. Prophylaxis and treatment for COVID-19 should be considered in patients with preexisting neuroinflammatory disorders at high risk for developing severe COVID-19.

The Heart–Brain Interplay in Multiple Sclerosis from Pathophysiology to Clinical Practice: A Narrative Review

Multiple sclerosis (MS) is a chronic neurological disorder characterized by inflammation in the central nervous system (CNS) that leads to neurodegeneration. The clinical course is highly variable, but its prevalence is rising worldwide, partly thanks to novel disease-modifying therapies. Additionally, the lifespan of people with MS is increasing, and for this reason, it is fundamental to have a multidisciplinary approach to MS. MS may be associated with cardiovascular diseases (CVD), but there is scarce attention on this issue. In particular, CNS is essential in regulating the autonomic system and heart activity. Moreover, cardiovascular risk factors show a higher prevalence in MS patients. On the other hand, conditions like Takotsubo syndrome are rare complications of MS. The parallelism between MS and myocarditis is also interesting. Finally, cardiac toxicity represents a not infrequent adverse reaction to MS drugs. This narrative review aims to provide an overview of cardiovascular complications in MS and their management to prompt further clinical and pre-clinical research on this topic.

Sudden Death Associated With Possible Flare-Ups of Multiple Sclerosis After COVID-19 Vaccination and Infection: A Case Report and Literature Review

We present an autopsy case of a 19-year-old man with a history of epilepsy whose unwitnessed sudden death occurred unexpectedly in the night. About 4 years before death, he was diagnosed with unilateral optic neuritis (ON). Demyelinating disease was suspected, but he was lost to follow up after the recovery. Six months before death, he received a second dose of mRNA coronavirus disease 2019 (COVID-19) vaccine. Three months before death, he experienced epileptic seizures for the first time. Seventeen days before death, he was infected with COVID-19, which showed self-limited course under home isolation. Several days before death, he complained of seizures again at night. Autopsy revealed multifocal gray-tan discoloration in the cerebrum. Histologically, the lesions consisted of active and inactive demyelinated plaques in the perivenous area of the white matter. Perivascular lymphocytic infiltration and microglial cell proliferation were observed in both white matter and cortex. The other major organs including heart and lung were unremarkable. Based on the antemortem history and postmortem findings, the cause of death was determined to be multiple sclerosis with suspected exacerbation. The direct or indirect involvement of cortex and deep gray matter by exacerbated multiple sclerosis may explain the occurrence of seizures. Considering the absence of other structural abnormalities except the inflammatory demyelination of the cerebrum, fatal arrhythmia or laryngospasm in the terminal epileptic seizure may explain his sudden unexpected death in the benign circumstances. In this case, the onset of seizure was preceded by COVID-19 vaccination, and the exacerbation of seizure was preceded by COVID-19 infection, respectively. Literature reporting first manifestation or relapse of multiple sclerosis temporally associated with COVID-19 vaccination or infection are reviewed.

COVID-19: A trigger of autoimmune diseases

The SARS-coronavirus-2 (SARS-CoV-2) that causes coronavirus disease 2019 (COVID-19), has spread worldwide and caused a global health emergency. SARS-CoV-2 is a coronaviridae virus that infects target cells by interacting with the plasma membrane-expressed angiotensin-converting enzyme 2 (ACE2) via the S1 component of the S protein. Effective host immune response to SARS-CoV-2 infection, which includes both innate and adaptive immunity, is critical for virus management and elimination. The intensity and outcome of COVID-19 may be related to an overabundance of pro-inflammatory cytokines, which results in a "cytokine storm" and acute respiratory distress syndrome. After SARS-CoV-2 infection, the immune system's hyperactivity and production of autoantibodies may result in autoimmune diseases such as autoimmune hemolytic anemia, autoimmune thrombocytopenia, Guillain-Barré syndrome, vasculitis, multiple sclerosis, pro-thrombotic state, and diffuse coagulopathy, as well as certain autoinflammatory conditions such as Kawasaki disease in children. We have reviewed the association between COVID-19 and autoimmune disorders in this article.

Multiple sclerosis (MS) and neuromyelitis optica spectrum disorder (NMOSD) following COVID-19 vaccines: A systematic review

BACKGROUND

The global COVID-19 pandemic began in March 2019, and given the number of casualties and adverse effects on the economy, society, and all aspects of the health system, efforts have been made to develop vaccines from the beginning of the pandemic. Numerous vaccines against COVID-19 infection have been developed in several technologies and have spread rapidly. There have been reported multiple complications of the COVID-19 vaccines as with other vaccines. A number of studies have reported multiple sclerosis (MS ) and neuromyelitis optica spectrum disorder (NMOSD) as complications of COVID-19 vaccines.

METHODS

First, we found 954 studies from 4 databases (PubMed, Embase, Scopus, and Web of Science) from inception to March 1^st, 2022. Next, duplicate articles were eliminated, and 476 studies remained. Then 412 studies were removed according to inclusion and exclusion criteria. After obtaining the full text of 64 articles, 12 studies were selected finally.

RESULTS

The data were extracted from included studies in a table. Our data includes demographic data, comorbidities, vaccines information and side effects, NMOSD and MS symptoms, laboratory and cerebrospinal fluid (CSF) findings, magnetic resonance imaging (MRI) results, treatment, and outcome of all cases.

CONCLUSION

MS and NMOSD are two neuroinflammatory disorders that arise in the CNS. Cases of MS and NMOSD have been reported following COVID-19 vaccination. Nevertheless, more studies with more subjects are needed to assess any possible relationship between the COVID-19 vaccine and central nervous system demyelination.

Newly Diagnosed Tumefactive Demyelinating Lesion and Multiple Sclerosis After COVID-19 Infection

Introduction

To describe the parainfectious or postinfectious effects of COVID-19 infection on the first demyelinating presentation of Multiple Sclerosis and tumefactive demyelinating lesion (TDL) developing with Longitudinally Extensive Transverse Myelitis (LETM).

Methods

We present six patients who presented with a first CNS demyelination event or whose demyelinating lesions had aggravated after COVID-19 infection between May and December 2020. Nasopharyngeal swab SARS-CoV-2 PCR positivity was detected in five cases and cerebrospinal fluid (CSF) PCR was positive in one. The symptoms, neurological signs, radiological and CSF findings of the cases were examined.

Results

A 24-year-old woman presented with LETM aggravated by COVID-19, accompanied by a newly developed open-ring enhanced TDL. Four patients were diagnosed with the first presentation of MS, and one presented with clinically isolated syndrome according to the McDonald 2017 criteria. The interval between SARS-CoV-2 infection and the onset of clinical symptoms ranged from 4-93 days. All of the cases present with pyramidal or brain stem findings and have high brain and/or spinal MRI load. This suggests the moderate activity of CNS demyelinating disease after COVID-19 infection.

Conclusions

Based on this case series, all these first demyelinating events suggested that COVID-19 infection might trigger or exacerbate CNS demyelinating disease. SARS-CoV-2 plays a role in the clinical onset of Multiple Sclerosis. Active delayed demyelination developed within the first three months. This can be explained by COVID-triggered neuroimmune response that had been latent, and the initiation of the active disease process began with triggering or aggravation of the lesions in MRI. Multiple Sclerosis should be maintained during the COVID-19 pandemic.

Autoimmunity and Immunodeficiency in Severe SARS-CoV-2 Infection and Prolonged COVID-19

SARS-CoV-2 causes the complex and heterogeneous illness known as COVID-19. The disease primarily affects the respiratory system but can quickly become systemic, harming multiple organs and leading to long-lasting sequelae in some patients. Most infected individuals are asymptomatic or present mild symptoms. Antibodies, complement, and immune cells can efficiently eliminate the virus. However, 20% of individuals develop severe respiratory illness and multiple organ failure. Virus replication has been described in several organs in patients who died from COVID-19, suggesting a compromised immune response. Immunodeficiency and autoimmunity are responsible for this impairment and facilitate viral escape. Mutations in IFN signal transduction and T cell activation are responsible for the inadequate response in young individuals. Autoantibodies are accountable for secondary immunodeficiency in patients with severe infection or prolonged COVID-19. Antibodies against cytokines (interferons α, γ and ω, IL1β, IL6, IL10, IL-17, IL21), chemokines, complement, nuclear proteins and DNA, anticardiolipin, and several extracellular proteins have been reported. The type and titer of autoantibodies depend on age and gender. Organ-specific autoantibodies have been described in prolonged COVID-19. Their role in the disease is under study. Autoimmunity and immunodeficiency should be screened as risk factors for severe or prolonged COVID-19.

Central nervous system (CNS) inflammatory demyelinating diseases (IDDs) associated with COVID-19: A case series and review

BACKGROUND

Over the past two years, SARS-CoV-2 has frequently been documented with various post and para-infectious complications, including cerebrovascular, neuromuscular, and some demyelinating conditions such as acute disseminated encephalomyelitis (ADEM). We report two rare neurological manifestations post-COVID-19 infection; multiple sclerosis (MS) and myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD). Further, we reviewed other CNS inflammatory demyelinating diseases (IDDs) associated with SARS-CoV-2, including optic neuritis (ON) and neuromyelitis optica spectrum disorders (NMOSD).

METHODS

A descriptive analysis and literature search of Google Scholar and PubMed was conducted by two independent reviewers from December 1st, 2019, to March 30th, 2022, and included all the case studies of MS, MOGAD, NMOSD, and ON associated with COVID-19 infection.

CASE PRESENTATIONS

Case 1 (MS) was a 24-year-old female with paresthesia and bilateral weakness one week after COVID-19 symptom onset who showed demyelinating plaques and 12 isolated oligoclonal bands (OCBs). Case 2 (MOGAD) was a 41-year-old male with encephalomyelitis 16 days after COVID-19, who later developed MOG-antibody-associated optic neuritis.

RESULTS

Out of 18 cases, NMOSD was the most common post-COVID manifestation (7, 39%), followed by MOGAD (5, 28%), MS (4, 22%), and isolated ON (2, 11%). The median duration between the onset of COVID-19 symptom onset and neurological symptoms was 14 days. 61% of these were male, with a mean age of 35 years. IVMP was the treatment of choice, and nearly all patients made a full recovery, with zero fatalities.

CONCLUSIONS

Although these neurological sequelae are few, physicians must be cognizant of their underlying pathophysiology and associated clinical and neuro-diagnostic findings when treating COVID-19 patients with atypical presentations.

Initial clinical presentation of multiple sclerosis with concurrent COVID-19 infection: Case report and literature review

The Article Abstract is not available.

COVID-19 and the risk of CNS demyelinating diseases: A systematic review

Background

Viral infections are a proposed possible cause of inflammatory central nervous system (CNS) demyelinating diseases, including multiple sclerosis (MS), neuromyelitis optica spectrum disorder (NMOSD), and myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD). During the past 2 years, CNS demyelinating events associated with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection have been reported, but causality is unclear.

Objective

To investigate the relationship between CNS demyelinating disease development and exacerbation with antecedent and/or concurrent SARS-CoV-2 infection.

Methods

A systematic literature review of all publications describing either a new diagnosis or relapse of CNS demyelinating diseases (MS, NMOSD, MOGAD) in association with SARS-CoV-2 infection was performed utilizing PRISMA guidelines. Descriptive statistics were used for data analysis, using a case analysis approach.

Results

Sixty-seven articles met the inclusion criteria for the study. Most of the reported cases of NMOSD (n = 13, 72.2% of reported cases) and MOGAD (n = 27, 96.5% of reported cases) were of new disease onset, presenting with typical clinical and radiographic features of these conditions, respectively. In contrast, reported MS cases varied amongst newly diagnosed cases (n = 10, 10.5% of reported cases), relapses (n = 63, 66.4%) and pseudo-relapses (n = 22, 23.2%). The median duration between COVID-19 infection and demyelinating event onset was 11.5 days (range 0–90 days) in NMOSD, 6 days (range−7 to +45 days) in MOGAD, and 13.5 days (range−21 to +180 days) in MS. Most cases received high-dose corticosteroids with a good clinical outcome.

Conclusion

Based upon available literature, the rate of CNS demyelinating events occurring in the setting of preceding or concurrent SARS-CoV-2 infection is relatively low considering the prevalence of SARS-CoV-2 infection. The clinical outcomes of new onset or relapsing MS, NMOSD, or MOGAD associated with antecedent or concurrent infection were mostly favorable. Larger prospective epidemiological studies are needed to better delineate the impact of COVID-19 on CNS demyelinating diseases.

SARS-CoV-2 infection in multiple sclerosis patients: interaction with treatments, adjuvant therapies, and vaccines against COVID-19

The SARS-CoV-2 pandemic has raised particular concern for people with Multiple Sclerosis, as these people are believed to be at increased risk of infection, especially those being treated with disease-modifying therapies. Therefore, the objective of this review was to describe how COVID-19 affects people who suffer from Multiple Sclerosis, evaluating the risk they have of suffering an infection by this virus, according to the therapy to which they are subjected as well as the immune response of these patients both to infection and vaccines and the neurological consequences that the virus can have in the long term. The results regarding the increased risk of infection due to treatment are contradictory. B-cell depletion therapies may cause patients to have a lower probability of generating a detectable neutralizing antibody titer. However, more studies are needed to help understand how this virus works, paying special attention to long COVID and the neurological symptoms that it causes.

[A case of polyneuropathy after COVID-19 vaccine]

A 43-year-old-woman developed paresthesia, weakness of limbs, dysphagia and deep sensory impairment 12 days after vaccination of Pfizer COVID-19 vaccine. Her deep tendon reflexes were absent and cerebrospinal fluid showed normal cell counts and protein level. Anti-ganglioside antibodies were negative, and F wave frequency was decreased in nerve conduction studies. We diagnosed her as immune mediated polyneuropathy caused by COVID-19 vaccine, and plasma exchange improved her symptoms. Compared with Guillain-Barré syndrome and polyneuropathy following COVID-19 infection and COVID-19 vaccination, deep sensory impairment was the most characteristic of this case. We supposed that non-antigen specific mechanism played an important role in the pathogenesis of this case.

A Systematic Review on Neurological Aspects of COVID-19: Exploring the Relationship Between COVID-19-Related Olfactory Dysfunction and Neuroinvasion

Objectives

To identify neurological aspects of Coronavirus disease 2019 (COVID-19) and to investigate COVID-19 infected patients with and without olfactory dysfunction in relation to polymerase chain reaction (PCR) assay results for severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) in the cerebrospinal fluid (CSF).

Methods

PubMed and EMBASE databases were searched until March 26, 2021, for observational studies with COVID-19 patients that had performed CSF PCR assay due to the neurologic symptom and reported anosmia status.

Results

Initially, 2,387 studies were identified;167 studies performed SARS-CoV-2 CSF PCR assay, of which our review comprised 45 observational studies that conducted CSF PCR assay for SARS-CoV-2 in 101 patients and reported anosmia status in 55 of 101 patients. Central and peripheral neurological manifestations observed in COVID-19 patients were diverse. The most common neurological diagnoses were Guillain-Barré syndrome (GBS) and its variants (24%), followed by encephalopathy (21%). The SARS-CoV-2 PCR assay was positive in only four CSF samples, of which two patients had olfactory dysfunction while the others did not.

Conclusions

The neurological spectrum of COVID-19 is diverse, and direct neuroinvasion of SARS-CoV-2 is rare. The neuroprotection against SARS-CoV-2 in COVID-19 patients with anosmia is controversial, as an equal number of patients with and without olfactory dysfunction had positive CSF PCR results for SARS-CoV-2 in our study, and further studies are required to provide more insight into this topic.

Acute disseminated encephalomyelitis (ADEM) following SARS-CoV-2 infection: A case report from Iran

The new coronavirus disease 2019 (COVID-19) outbreak has rapidly spread throughout the world, becoming a serious public health problem. COVID-19, in addition to respiratory symptoms, has neurotropic characteristics that can impact the nervous system. We present a 22-year-old female who developed diplopia and numbness of her limbs eight days after affecting by COVID-19 and she showed a left-sided outward gaze palsy without any history of previous a specific illness or medication. Supratentorial, infratentorial, and cervical cord enhancing plaques confirmed an acute demyelinating process in favor of Acute disseminated encephalomyelitis (ADEM). Her oligoclonal bands (OCB) were positive as well. As a result, a provisional diagnosis of ADEM was made. Her condition improved dramatically after starting corticosteroids and rituximab.

K18- and CAG-hACE2 Transgenic Mouse Models and SARS-CoV-2: Implications for Neurodegeneration Research

COVID-19, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is a global pandemic that might lead to very serious consequences. Notably, mental status change, brain confusion, and smell and taste disorders along with neurological complaints have been reported in patients infected with SARS-CoV-2. Furthermore, human brain tissue autopsies from COVID-19 patients show the presence of SARS-CoV-2 neuroinvasion, which correlates with the manifestation of meningitis, encephalitis, leukocyte infiltration, and neuronal damage. The olfactory mucosa has been suggested as a way of entry into the brain. SARS-CoV-2 infection is also known to provoke a hyper-inflammatory reaction with an exponential increase in the production of pro-inflammatory cytokines leading to systemic responses, even in the absence of direct infection of brain cells. Angiotensin-converting enzyme 2 (ACE2), the entry receptor of SARS-CoV-2, has been extensively demonstrated to be present in the periphery, neurons, and glial cells in different brain regions. To dissect the details of neurological complications and develop therapies helping COVID-19 survivors regain pre-infection quality of life, the development of robust clinical models is highly warranted. Several human angiotensin-converting enzyme 2 (hACE2) transgenic mouse models have been developed and used for antiviral drug screening and vaccine development, as well as for better understanding of the molecular pathogenetic mechanisms of SARS-CoV-2 infection. In this review, we summarize recent results from the studies involving two such mouse models, namely K18- and CAG-hACE2 transgenics, to evaluate the direct and indirect impact of SARS-CoV-2 infection on the central nervous system.

Frequency of Neurological Diseases After COVID-19, Influenza A/B and Bacterial Pneumonia

Introduction

COVID-19 might affect the incidence of specific neurological diseases, but it is unknown if this differs from the risk following other infections. Here, we characterized the frequency of neurodegenerative, cerebrovascular, and immune-mediated neurological diseases after COVID-19 compared to individuals without COVID-19 and those with other respiratory tract infections.

Methods

This population-based cohort study utilized electronic health records covering ~50% of Denmark's population (n = 2,972,192). Between 02/2020 and 11/2021, we included individuals tested for COVID-19 or diagnosed with community-acquired bacterial pneumonia in hospital-based facilities. Additionally, we included individuals tested for influenza in the corresponding pre-pandemic period between 02/ 2018 and 11/2019. We stratified cohorts for in- and outpatient status, age, sex, and comorbidities.

Results

In total, 919,731 individuals were tested for COVID-19, of whom 43,375 tested positive (35,362 outpatients, 8,013 inpatients). Compared to COVID-negative outpatients, COVID-19 positive outpatients had an increased RR of Alzheimer's disease (RR = 3.5; 95%CI: 2.2–5.5) and Parkinson's disease (RR = 2.6; 95%CI: 1.7–4.0), ischemic stroke (RR = 2.7; 95%CI: 2.3–3.2) and intracerebral hemorrhage (RR = 4.8; 95%CI: 1.8–12.9). However, when comparing to other respiratory tract infections, only the RR for ischemic stroke was increased among inpatients with COVID-19 when comparing to inpatients with influenza (RR = 1.7; 95%CI: 1.2–2.4) and only for those >80 years of age when comparing to inpatients with bacterial pneumonia (RR = 2.7; 95%CI: 1.2–6.2). Frequencies of multiple sclerosis, myasthenia gravis, Guillain-Barré syndrome and narcolepsy did not differ after COVID-19, influenza and bacterial pneumonia.

Conclusion

The risk of neurodegenerative and cerebrovascular, but not neuroimmune, disorders was increased among COVID-19 positive outpatients compared to COVID-negative outpatients. However, except for ischemic stroke, most neurological disorders were not more frequent after COVID-19 than after other respiratory infections.

Melatonin and multiple sclerosis: antioxidant, anti-inflammatory and immunomodulator mechanism of action

BACKGROUND

Melatonin is an indole hormone secreted primarily by the pineal gland that showing anti-oxidant, anti-inflammatory and anti-apoptotic capacity. It can play an important role in the pathophysiological mechanisms of various diseases. In this regard, different studies have shown that there is a relationship between Melatonin and Multiple Sclerosis (MS). MS is a chronic immune-mediated disease of the Central Nervous System.

AIM

The objective of this review was to evaluate the mechanisms of action of melatonin on oxidative stress, inflammation and intestinal dysbiosis caused by MS, as well as its interaction with different hormones and factors that can influence the pathophysiology of the disease.

RESULTS

Melatonin causes a significant increase in the levels of catalase, superoxide dismutase, glutathione peroxidase, glutathione and can counteract and inhibit the effects of the NLRP3 inflammasome, which would also be beneficial during SARS-CoV-2 infection. In addition, melatonin increases antimicrobial peptides, especially Reg3β, which could be useful in controlling the microbiota.

CONCLUSION

Melatonin could exert a beneficial effect in people suffering from MS, running as a promising candidate for the treatment of this disease. However, more research in human is needed to help understand the possible interaction between melatonin and certain sex hormones, such as estrogens, to know the potential therapeutic efficacy in both men and women.

Bioinformatics approach reveals the critical role of the NOD-like receptor signaling pathway in COVID-19-associated multiple sclerosis syndrome

Multiple sclerosis (MS) is a kind of central nervous system (CNS) autoimmune disease, which mainly damages nerves, the brain, and the spinal cord. Recently, several clinical cases reported the relativity between Coronavirus Disease 2019 (COVID-19) and the development of MS, but the mechanism of how COVID-19 affects the occurrence of MS was still not clear. It is bioinformatics technology that we use to explore the potential association at the gene level. The genetic information related to the two diseases was collected from the DisGNET platform for functional protein network analysis and used STRING to identify the complete gene set. The protein–protein interaction (PPI) network was analyzed by STRING. Finally, in the GEO database, we selected peripheral blood mononuclear cell (PBMC) RNA sequencing data (GSE164805, GSE21942) from COVID-19 patients and MS patients to verify the potential cross mechanism between the two diseases. The similar gene set of immune or inflammation existed between the patients with COVID-19 and ones with MS, including L2RA, IFNG, IL1B, NLRP3, and TNF. Interaction network analysis among proteins revealed that IL1B, P2RX7, IFNB1, IFNB1, TNF, and CASP1 enhanced the network connectivity between the combined gene set of COVID-19 and MS associated with NOD-like receptor (NLR) signaling. The involvement of NLR signaling in both diseases was further confirmed by comparing peripheral blood monocyte samples from COVID-19 and MS patients. Activation of NLR signaling was found in both COVID-19 and MS. The PBMC samples analyses also indicated the involvement of the NLR signaling pathway. Taken together, our data analyses revealed that the NLR signaling pathway might play a critical role in the COVID-19-related MS.

SARS-CoV-2 and Multiple Sclerosis: Potential for Disease Exacerbation

While the respiratory tract is the primary route of entry for SARS-CoV-2, evidence shows that the virus also impacts the central nervous system. Intriguingly, case reports have documented SARS-CoV-2 patients presenting with demyelinating lesions in the brain, spinal cord, and optic nerve, suggesting possible implications in neuroimmune disorders such as multiple sclerosis (MS) and other related neuroimmune disorders. However, the cellular mechanisms underpinning these observations remain poorly defined. The goal of this paper was to review the literature to date regarding possible links between SARS-CoV-2 infection and neuroimmune demyelinating diseases such as MS and its related disorders, with the aim of positing a hypothesis for disease exacerbation. The literature suggests that SARS-CoV, SARS-CoV-2, and orthologous murine coronaviruses invade the CNS via the olfactory bulb, spreading to connected structures via retrograde transport. We hypothesize that a glial inflammatory response may contribute to damaged oligodendrocytes and blood brain barrier (BBB) breakdown, allowing a second route for CNS invasion and lymphocyte infiltration. Potential for molecular mimicry and the stimulation of autoreactive T cells against myelin is also described. It is imperative that further studies on SARS-CoV-2 neuroinvasion address the adverse effects of the virus on myelin and exacerbation of MS symptoms, as nearly 3 million people suffer from MS worldwide.

SARS-CoV-2-related Myelin Oligodendrocyte Glycoprotein Antibody-associated Disease: A Case Report and Literature Review

We herein report a case of myelin oligodendrocyte glycoprotein (MOG) antibody-associated disease after severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. A 24-year-old woman developed unilateral optic neuritis 3 weeks after contracting coronavirus disease 2019 (COVID-19), followed by intracranial demyelinating lesions and myelitis. Since serum anti-MOG antibody was positive, we diagnosed MOG antibody-associated disease. Immunotherapy with steroids resulted in the rapid improvement of neurological symptoms. This is a suggestive case, as there are no reports of MOG antibody-associated disease with multiple neurological lesions occurring after COVID-19. The response to immunotherapy was favorable. This case suggests that it is important to measure anti-MOG antibodies in patients who develop inflammatory neurological disease after COVID-19.

Impact of immunotherapies on COVID-19 outcomes in multiple sclerosis patients

INTRODUCTION

SARS-CoV-2 pandemic has led the scientific community to maximize efforts to prevent infections and disease severity in patients with multiple sclerosis (pwMS). We analyze the impact of immunotherapies on COVID-19 outcomes in pwMS, providing our interpretation of data.

AREAS COVERED

Infections, hospitalizations, intensive care unit admissions and death rates in COVID-19 pwMS are comparable to general population. Severity of disability, MS clinical phenotype, age and comorbidities, along with the use of intravenous methylprednisolone and anti-CD20 treatments, are risk factors for COVID-19 severity. Disease modifying treatments (DMTs) can be safely started and continued during the pandemic. Benefit-risk evaluation is mandatory when managing second-line therapies, to balance risk of worse COVID-19 outcomes and MS reactivation. COVID-19 vaccination is safe in MS and its efficacy could be reduced in fingolimod and ocrelizumab-treated patients.

EXPERT OPINION

Rate of (re)-infection and outcomes with SARS-CoV-2 variants in pwMS and antiviral properties of DMTs need to be further explored. Data on COVID-19 in pregnant MS women, children and elderly pwMS are limited. Evidence on long-term effects of infection is needed. Impact of emerging DMTs on COVID-19 should be investigated. More data and longer follow-up are needed to characterize long-term efficacy and safety profile of vaccinations in pwMS.

SARS-CoV-2 triggering autoimmune diseases

Autoimmunity, hyperstimulation of the immune system, can be caused by a variety of reasons. Viruses are thought to be important environmental elements that contribute to the development of autoimmune antibodies. It seems that viruses cause autoimmunity with mechanisms such as molecular mimicry, bystander activation of T cells, transient immunosuppression, and inflammation, which has also been seen in post-Covid-19 autoimmunity. Infection of respiratory epithelium by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) dysregulates the immune response, triggers both innate and acquired immunity that led to the immune system's hyperactivation, excessive cytokine secretion known as “cytokine storm,” and finally acute respiratory distress syndrome (ARDS) associated with high mortality. Any factor in the body that triggers chronic inflammation can contribute to autoimmune disease, which has been documented during the Covid-19 pandemic. It has been observed that some patients produce autoantibody and autoreactive CD4⁺ and CD8⁺ T cells, leading to the loss of self-tolerance. However, there is a scarcity of evidence defining the precise molecular interaction between the virus and the immune system to elicit autoreactivity. Here, we present a review of the relevant immunological findings in Covid-19 and the current reports of autoimmune disease associated with the disease.

Case report: Multiple sclerosis diagnosis after anterior lumbar interbody fusion and presumed COVID-19 infection

Background:

Multiple sclerosis (MS) is an autoimmune demyelinating disease of the central nervous system that may present with a wide variety of clinical presentations. However, there can be substantial overlap between symptoms from MS and those caused by lumbar spondylosis and/or postviral plexopathies.

Case Description:

A 33-year-old female with a history of an L5-S1 anterior lumbar interbody fusion and exposure to the SARS-CoV-2 virus developed postoperative worsening of her symptoms interpreted as “radiculopathy.” Despite a subsequent L5-S1 fusion, she continued to neurologically deteriorate and was ultimately diagnosed with MS.

Conclusion:

The initial symptoms/signs of MS may mimic lumbar radiculopathy and or postviral plexopathy (i.e., due to recent COVID-19). This report should serve as a warning to future spinal surgeons to better differentiate between radicular and other “complaints,” sufficient to avoid unnecessary repeated spinal surgery.

Autoimmune Encephalitis in COVID-19 Infection: Our Experience and Systematic Review of the Literature

The neurologic complications of COVID-19 infection are frequent in hospitalized patients; a high percentage of them present neurologic manifestations at some point during the course of their disease. Headache, muscle pain, encephalopathy and dizziness are among the most common complications. Encephalitis is an inflammatory condition with many etiologies. There are several forms of encephalitis associated with antibodies against intracellular neuronal proteins, cell surfaces or synaptic proteins, referred to as autoimmune encephalitis. Several case reports published in the literature document autoimmune encephalitis cases triggered by COVID-19 infection. Our paper first presents our experience in this issue and then systematically reviews the literature on autoimmune encephalitis that developed in the background of SARS-CoV-2 infections and also discusses the possible pathophysiological mechanisms of auto-immune-mediated damage to the nervous system. This review contributes to improve the management and prognosis of COVID-19-related autoimmune encephalitis.

Coronaviruses and their relationship with multiple sclerosis: is the prevalence of multiple sclerosis going to increase after the Covid-19 pandemia?

The purpose of this review is to examine whether there is a possible (etiological/triggering) relationship between infection with various Coronaviruses, including Severe Acute Respiratory Syndrome-related Coronavirus-2 (SARS-CoV-2), the virus responsible for the Coronavirus disease-19 (Covid-19) pandemia, and Multiple Sclerosis (MS), and whether an increase of the prevalence of MS after the current Covid-19 pandemia should be expected, examining new and preexisting data. Although the exact pathogenesis of MS remains unknown, environmental agents seem to greatly influence the onset of the disease, with viruses being the most popular candidate. Existing data support this possible etiological relationship between viruses and MS, and experimental studies show that Coronaviruses can actually induce an MS-like demyelinating disease in animal models. Findings in MS patients could also be compatible with this coronaviral MS hypothesis. More importantly, current data from the Covid-19 pandemia show that SARS-CoV-2 can trigger autoimmunity and possibly induce autoimmune diseases, in the Central Nervous System as well, strengthening the viral hypothesis of MS. If we accept that Coronaviruses can induce MS, it is reasonable to expect an increase in the prevalence of MS after the Covid-19 pandemia. This knowledge is of great importance in order to protect the aging groups that are more vulnerable against autoimmune diseases and MS specifically, and to establish proper vaccination and health policies.

Para and Post-COVID-19 CNS Acute Demyelinating Disorders in Children: A Case Series on Expanding the Spectrum of Clinical and Radiological Characteristics

Viral infections can serve as a trigger for variable autoimmune, antibody-mediated demyelinating disorders. There is accumulating evidence that the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus, causing coronavirus disease 2019 (COVID-19) infection and responsible for the current worldwide pandemic, can lead to a cascade of immune-mediated brain and spinal cord demyelinating injuries. However, such observation in the pediatric age group was only reported in very few patients. Thus, the heterogeneous spectrum of this phenomenon in children is still unfolding. We are reporting a case series of five pediatric patients with a variety of acute central nervous system (CNS) demyelinating disorders in the context of acute or recent COVID-19 infection. A 16-year-old female with anti-myelin oligodendrocyte glycoprotein (MOG) disorder, an eight-year-old male with acute disseminated encephalomyelitis (ADEM), a 13-year-old female with neuromyelitis optica spectrum disorder (NMOSD), and two 14 and 13-year-old females with new-onset multiple sclerosis (MS) are reported, all of whom presented acutely following COVID-19 infection. We propose that para and post-infectious CNS demyelinating disorders can potentially follow acute COVID-19 infection in children. Considering SARS-CoV-2 testing as a part of diagnostic workup is possibly useful. Awareness of the presence of this phenomenon can help in the recognition and management of those patients.

Does COVID-19 increase the long-term relapsing-remitting multiple sclerosis clinical activity? A cohort study

Background

Some current evidence is pointing towards an association between COVID-19 and worsening of multiple sclerosis (MS), stressing the importance of preventing COVID-19 among people with MS (pwMS). However, population-based evidence regarding the long-term post-COVID-19 course of relapsing-remitting multiple sclerosis (RRMS) was limited when this study was initiated.

Objective

To detect possible changes in MS clinical disease activity after COVID-19.

Methods

We conducted an observational study from July 2020 until July 2021 in the Isfahan MS clinic, comparing the trends of probable disability progression (PDP) – defined as a three-month sustained increase in expanded disability status scale (EDSS) score – and relapses before and after probable/definitive COVID-19 diagnosis in a cohort of people with RRMS (pwRRMS).

Results

Ninety pwRRMS were identified with definitive COVID-19, 53 of which were included in the final analysis. The PDP rate was significantly (0.06 vs 0.19, P = 0.04), and the relapse rate was insignificantly (0.21 vs 0.30, P = 0.30) lower post-COVID-19, compared to the pre-COVID-19 period. The results were maintained after offsetting by follow-up period in the matched binary logistic model. Survival analysis did not indicate significant difference in PDP-free (Hazard Ratio [HR] [95% CI]: 0.46 [0.12, 1.73], P = 0.25) and relapse-free (HR [95% CI]: 0.69 [0.31, 1.53], P = 0.36) survivals between the pre- and post-COVID-19 periods. Sensitivity analysis resulted similar measurements, although statistical significance was not achieved.

Conclusion

While subject to replication in future research settings, our results did not confirm any increase in the long-term clinical disease activity measures after COVID-19 contraction among pwRRMS.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12883-022-02590-9.