Changes in ganglioside antibody positivity rates during the COVID-19 pandemic

Domingo FG, Longley S, Patel S, Baddam S, Chimakurthy A. Post-COVID-19 Guillain-Barré Syndrome with GM1 and GD1b Antibodies: A Case Study and Literature Review

BACKGROUND The coronavirus disease 2019 (COVID-19) pandemic, caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has led to the emergence of various neurological complications, including Guillain-Barre syndrome (GBS). GBS is an acute, immune-mediated disorder characterized by progressive weakness, sensory deficits, and autonomic dysfunction. Anti-ganglioside antibodies are often seen in GBS; however, they are rarely reported in the setting of COVID-19-related GBS. We present a case of post-COVID-19 GBS with positive GM1 and GD1b antibodies. CASE REPORT An 86-year-old man presented with progressive quadriparesis, sensory deficits, and hyporeflexia 4 weeks after COVID-19 infection. Brain and spine imaging were unremarkable. Cerebrospinal fluid (CSF) analysis revealed albuminocytological dissociation, consistent with acute inflammatory demyelinating polyneuropathy (AIDP). Despite 2 courses of intravenous immunoglobulin (IVIG), the patient showed minimal improvement in muscle strength. Nerve conduction studies (NCS) revealed severe sensorimotor polyneuropathy, with axonal and demyelinating features. Serum testing showed elevated GM1 and GD1b anti-ganglioside antibody titers. CONCLUSIONS Although numerous cases of COVID-19-related GBS have been reported, anti-ganglioside antibody positivity, particularly GM1 and GD1b, is uncommon. The underlying mechanism is presumed to be autoimmune, likely triggered by molecular mimicry. Our case contributes to the evolving understanding of GBS immunology in the context of COVID-19. Although this case report may not alter current GBS management, the co-occurrence of GM1 and GD1b antibodies in post-COVID-19 GBS underscores the need for continued vigilance, immunological profiling, and research into potential prognostic and therapeutic implications.

Analysis of 977 Long COVID Patients Reveals Prevalent Neuropathy and Association with Anti-Ganglioside Antibodies

Background

Long COVID (LC) is a novel condition that is characterized by persistent symptoms that last from months to years following a SARS-CoV-2 infection. While LC symptoms vary widely, neuropathy is one of the most prevalent symptoms and drastically affects patients' quality of life. However, the underlying pathophysiology of LC neuropathy remains poorly understood. Here, we investigated the prevalence and potential mechanisms of LC neuropathy in the largest LC neuropathy cohort to date.

Methods

We conducted an observational study of 977 adults with LC at Dell Medical School. Participants underwent clinical assessments, skin punch biopsy, and comprehensive metabolic, endocrine and immunological profiling. A subset of patients received treatment with intravenous immunoglobulin (IVIG).

Findings

Neuropathic symptoms were reported by 55% (534/977) participants, with skin biopsy confirming small fiber neuropathy in 56.5% (48/85) cases, affecting both epidermal and autonomic nerve fibers. Common risk factors for neuropathy, including metabolic and endocrine disorders, did not fully explain neuropathic symptoms. While general immunological markers (lymphocyte, T cell, and B cell count and C reactive protein were unremarkable, unexpectedly, we detected anti-ganglioside antibodies (AGAs) in 25% of patients with LC neuropathy, a comparable rate to other AGA-associated neuropathies. Longitudinal testing revealed persistent AGA positivity, and multiple elevated AGAs in a subset of patients. In a pilot treatment cohort of eight patients, IVIG treatment resulted in improvement of patient reported neuropathic symptoms.

Interpretation

Our findings reveal a high prevalence of small fiber neuropathy in LC, with evidence suggesting an autoimmune mechanism involving AGAs in one in four LC neuropathy patients. The therapeutic response to IVIG further supports an autoimmune pathophysiology, suggesting potential benefits of immunomodulation in LC neuropathy patients.

The Impact of COVID-19 on the Guillain-Barré Syndrome Incidence

Despite the fact that the global COVID-19 pandemic has officially ended, we continue to feel its effects and discover new correlations between SARS-CoV-2 infection and changes in the organism that have occurred in patients. It has been shown that the disease can be associated with a variety of complications, including disorders of the nervous system such as a characteristic loss of smell and taste, as well as less commonly reported incidents such as cranial polyneuropathy or neuromuscular disorders. Nervous system diseases that are suspected to be related to COVID-19 include Guillain-Barré syndrome, which is frequently caused by viruses. During the course of the disease, autoimmunity destroys peripheral nerves, which despite its rare occurrence, can lead to serious consequences, such as symmetrical muscle weakness and deep reflexes, or even their complete abolition. Since the beginning of the pandemic, case reports suggesting a relationship between these two disease entities have been published, and in some countries, the increasing number of Guillain-Barré syndrome cases have also been reported. This suggests that previous contact with SARS-CoV-2 may have had an impact on their occurrence. This article is a review and summary of the literature that raises awareness of the neurological symptoms' prevalence, including Guillain-Barré syndrome, which may be impacted by the commonly occurring COVID-19 disease or vaccination against it. The aim of this review was to better understand the mechanisms of the virus's action on the nervous system, allowing for better detection and the prevention of its complications.

Site-Specific O-glycosylation of SARS-CoV-2 Spike Protein and Its Impact on Immune and Autoimmune Responses

The world-wide COVID-19 pandemic has promoted a series of alternative vaccination strategies aiming to elicit neutralizing adaptive immunity in the human host. However, restricted efficacies of these vaccines targeting epitopes on the spike (S) protein that is involved in primary viral entry were observed and putatively assigned to viral glycosylation as an effective escape mechanism. Besides the well-recognized N-glycan shield covering SARS-CoV-2 spike (S) proteins, immunization strategies may be hampered by heavy O-glycosylation and variable O-glycosites fluctuating depending on the organ sites of primary infection and those involved in immunization. A further complication associated with viral glycosylation arises from the development of autoimmune antibodies to self-carbohydrates, including O-linked blood group antigens, as structural parts of viral proteins. This outline already emphasizes the importance of viral glycosylation in general and, in particular, highlights the impact of the site-specific O-glycosylation of virions, since this modification is independent of sequons and varies strongly in dependence on cell-specific repertoires of peptidyl-N-acetylgalactosaminyltransferases with their varying site preferences and of glycan core-specific glycosyltransferases. This review summarizes the current knowledge on the viral O-glycosylation of the SARS-CoV-2 spike protein and its impact on virulence and immune modulation in the host.

Reported neurological symptoms after severe acute respiratory syndrome coronavirus type 2 infection: A systematic diagnostic approach

BACKGROUND AND PURPOSE

Following increasing demands of patients with suspected neurological symptoms after infection with severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2), the Department of Neurology at the Medical University of Vienna established a new outpatient clinic to systematically assess, diagnose, and document neurological complaints potentially associated with a prior SARS-CoV-2 infection.

METHODS

The data presented here include prospectively collected 156 outpatients from May 2021 to April 2022. Patients underwent semistandardized interviewing about symptoms with reported onset after SARS-CoV-2 infection, neurological examination, and comprehensive diagnostic workup.

RESULTS

Reported new onset symptoms after infection included fatigue (77.6%), subjective cognitive impairment (72.4%), headache (47.7%), loss of smell and/or taste (43.2%), and sleep disturbances (42.2%). Most patients had a mild coronavirus disease (COVID-19) disease course (84%) and reported comorbidities (71%), of which the most frequent were psychiatric disorders (34%). Frequency of symptoms was not associated with age, sex, or severity of COVID-19 course. A comprehensive diagnostic workup revealed no neurological abnormalities in the clinical examination, or electrophysiological or imaging assessments in the majority of patients (n = 143, 91.7%). Neuropsychological assessment of a subgroup of patients (n = 28, 17.9%) showed that cognitive impairments in executive functions and attention, anxiety, depression, and somatization symptoms were highly common.

CONCLUSIONS

In this systematic registry, we identified fatigue, cognitive impairment, and headache as the most frequently reported persisting complaints after SARS-CoV-2 infection. Structural neurological findings were rare. We also suspect a link between the growing burden of the COVID-19 pandemic on personal lives and the increase in reported neurological and psychiatric complaints.