Zika virus infection and Guillain-Barré syndrome: a review focused on clinical and electrophysiological subtypes

Host caveolin-1 facilitates Zika virus infection by promoting viral RNA replication

Zika virus (ZIKV) has gained notoriety in recent years because there are no targeted therapies or vaccines available so far. Caveolin-1 (Cav-1) in host cells plays crucial functions in the invasion of many viruses. However, its specific involvement in ZIKV infection has remained unclear. Here, we reveal that depleting Cav-1 leads to a substantial reduction in ZIKV RNA levels, protein expression and viral particle production, indicating that ZIKV exploits Cav-1 for its infection. By dissecting each stage of the viral life cycle, we unveil that, unlike its invasion role in many other viruses, Cav-1 depletion selectively impairs ZIKV replication, resulting in altered replication dynamics and reduced strand-specific RNA levels, but does not affect viral entry, maturation and release. These results reveal an unforeseen function of Cav-1 in facilitating ZIKV replication, which provides new insights into the intricate interaction between Cav-1 and ZIKV and underscores Cav-1 as a potential candidate for anti-ZIKV approaches.

COVID-19-associated serum and cerebrospinal fluid cytokines in post- versus para-infectious SARS-CoV-2-related Guillain-Barré syndrome

INTRODUCTION

Guillain-Barré syndrome associated with Coronavirus-2-related severe acute respiratory syndrome (COV-GBS) occurs as para- or post-infectious forms, depending on the timing of disease onset. In these two forms, we aimed to compare the cerebrospinal fluid (CSF) and serum proinflammatory cytokine profiles to evaluate differences that could possibly have co-pathogenic relevance.

MATERIALS AND METHODS

We studied a retrospective cohort of 26 patients with either post-COV-GBS (n = 15), with disease onset occurring > 7 days after SARS-CoV-2 infection, or para-COV-GBS (n = 11), with disease onset 7 days or less. TNF-α, IL-6, and IL-8 were measured in the serum with SimplePlex™ Ella™ immunoassay. In addition to the para-/post-COV-GBS patients, serum levels of these cytokines were determined in those with non-COVID-associated-GBS (NC-GBS; n = 43), paucisymptomatic SARS-CoV-2 infection without GBS (COVID, n = 20), and in healthy volunteers (HV; n = 12). CSF cytokine levels were measured in patients with para-/post-COV-GBS, in those with NC-GBS (n = 29), or with Alzheimer's disease (AD; n = 24).

RESULTS

Serum/CSF cytokine levels did not differ in para- vs post-COV-GBS. We found that SARS-CoV-2 infection raises the serum levels of TNF-α, IL-6, and IL-8, as well as an increase of IL-6 (in serum and CSF) and IL-8 (in CSF) in either NC-GBS or COV-GBS than controls. CSF and serum cytokine levels resulted independent one with another.

CONCLUSIONS

The change of cytokines linked to SARS-CoV-2 in COV-GBS appears to be driven by viral infection, although it has unique characteristics in GBS as such and does not account for cases with para- or post-infectious onset.

Bystander activated CD8+ T cells mediate neuropathology during viral infection via antigen-independent cytotoxicity

Although many viral infections are linked to the development of neurological disorders, the mechanism governing virus-induced neuropathology remains poorly understood, particularly when the virus is not directly neuropathic. Using a mouse model of Zika virus (ZIKV) infection, we found that the severity of neurological disease did not correlate with brain ZIKV titers, but rather with infiltration of bystander activated NKG2D+CD8+ T cells. Antibody depletion of CD8 or blockade of NKG2D prevented ZIKV-associated paralysis, suggesting that CD8+ T cells induce neurological disease independent of TCR signaling. Furthermore, spleen and brain CD8+ T cells exhibited antigen-independent cytotoxicity that correlated with NKG2D expression. Finally, viral infection and inflammation in the brain was necessary but not sufficient to induce neurological damage. We demonstrate that CD8+ T cells mediate virus-induced neuropathology via antigen-independent, NKG2D-mediated cytotoxicity, which may serve as a therapeutic target for treatment of virus-induced neurological disease.

Tropism and immune response of chikungunya and zika viruses: An overview

Zika virus (ZIKV) and chikungunya virus (CHIKV) are two medically important vector-borne viruses responsible for causing significant disease burden in humans, including neurological sequelae/complications. Besides sharing some common clinical features, ZIKV has major shares in causing microcephaly and brain malformations in developing foetus, whereas CHIKV causes chronic joint pain/swelling in infected individuals. Both viruses have a common route of entry to the host body. i.e., dermal site of inoculation through the bite of an infected mosquito and later taken up by different immune cells for further dissemination to other areas of the host body that lead to a range of immune responses via different pathways. The immune responses generated by both viruses have similar characteristics with varying degrees of inflammation and activation of immune cells. However, the overall response of immune cells is not fully explored in the context of ZIKV and CHIKV infection. The knowledge of cellular tropism and the immune response is the key to understanding the mechanisms of viral immunity and pathogenesis, which may allow to develop novel therapeutic strategies for these viral infections. This review aims to discuss recent advancements and identify the knowledge gaps in understanding the mechanism of cellular tropism and immune response of CHIKV and ZIKV.

Metformin restrains ZIKV replication and alleviates virus-induced inflammatory responses in microglia

The re-emergence of Zika virus (ZIKV) remains a major public health threat that has raised worldwide attention. Accumulating evidence suggests that ZIKV can cause serious pathological changes to the human nervous system, including microcephaly in newborns. Recent studies suggest that metformin, an established treatment for diabetes may play a role in viral infection; however, little is known about the interactions between ZIKV infection and metformin administration. Using fluorescent ZIKV by flow cytometry and immunofluorescence imaging, we found that ZIKV can infect microglia in a dose-dependent manner. Metformin diminished ZIKV replication without the alteration of viral entry and phagocytosis. Our study demonstrated that metformin downregulated ZIKV-induced inflammatory response in microglia in a time- and dose-dependent manner. Our RNA-Seq and qRT-PCR analysis found that type I and III interferons (IFN), such as IFNα2, IFNβ1 and IFNλ3 were upregulated in ZIKV-infected cells by metformin treatment, accompanied with the downregulation of GBP4, OAS1, MX1 and ISG15. Together, our results suggest that metformin-mediated modulation in multiple pathways may attribute to restraining ZIKV infection in microglia, which may provide a potential tool to consider for use in unique clinical circumstances.

How viral infections cause neuronal dysfunction: a focus on the role of microglia and astrocytes

In recent decades, a number of infectious viruses have emerged from wildlife or reemerged that pose a serious threat to global health and economies worldwide. Although many of these viruses have a specific target tissue, neurotropic viruses have evolved mechanisms to exploit weaknesses in immune defenses that eventually allow them to reach and infect cells of the central nervous system (CNS). Once in the CNS, these viruses can cause severe neuronal damage, sometimes with long-lasting, life-threatening consequences. Remarkably, the ability to enter the CNS and cause neuronal infection does not appear to determine whether a viral strain causes neurological complications. The cellular mechanisms underlying the neurological consequences of viral infection are not fully understood, but they involve neuroimmune interactions that have so far focused mainly on microglia. As the major immune cells in the brain, reactive microglia play a central role in neuroinflammation by responding directly or indirectly to viruses. Chronic reactivity of microglia leads to functions that are distinct from their beneficial roles under physiological conditions and may result in neuronal damage that contributes to the pathogenesis of various neurological diseases. However, there is increasing evidence that reactive astrocytes also play an important role in the response to viruses. In this review article, we summarize the recent contributions of microglia and astrocytes to the neurological impairments caused by viral infections. By expanding knowledge in this area, therapeutic approaches targeting immunological pathways may reduce the incidence of neurological and neurodegenerative disorders and increase the therapeutic window for neural protection.

Deciphering changes in the incidence of the Guillain-Barré syndrome during the COVID-19 pandemic: a nationwide time-series correlation study

Background

Postinfectious autoimmunity is a hallmark of Guillain-Barré syndrome (GBS), and GBS incidence closely parallels that of its immune triggers. Sociobehavioural interventions implemented during the COVID-19 pandemic have altered the infectious disease landscape.

Methods

This nationwide time-series correlation study analysed GBS incidence, sentinel surveillance and SARS-CoV-2 vaccination data from January 2017 to December 2021 in the National Health Insurance Service and Korean Disease Control and Prevention Agency databases. The incidence of GBS and sentinel gastrointestinal and respiratory infectious diseases during the pandemic (2020-2021) was estimated and compared with both prepandemic (2017-2019) and incidence predicted in a time-series forecasting model. Time-series correlation analysis was used to examine the temporal association between GBS, infectious triggers and SARS-CoV-2 vaccination.

Results

During the pandemic, the total crude cumulative incidence rate was 2.1 per 100 000 population, which is lower than the prepandemic incidence, especially in age groups of less than 60 years. Seasonality was briefly interrupted during the winter of 2021. The majority of respiratory and some gastrointestinal conditions had a lower-than-expected incidence during the pandemic. Compared with the prepandemic state, during the pandemic period a higher number of gastrointestinal pathogens (Escherichia coli, Campylobacter spp., Clostridium perfringens, Yersinia enterocolitica and enteric adenovirus) had significant, moderate-to-strong positive temporal associations with GBS. The temporal association between SARS-CoV-2 infection and GBS was not significant, but SARS-CoV-2 vaccination exhibited a strong positive temporal association with GBS in 2021.

Conclusion

The incidence of GBS and sentinel infectious diseases decreased to below-expected levels during the pandemic, with the former attributable to the decreased incidence of non-COVID-19 respiratory and gastrointestinal infections. The evolving incidence of autoimmune postinfectious phenomena following the pandemic needs attention.

The Innate Defense in the Zika-Infected Placenta

Zika virus (ZIKV) is an arthropod-borne virus that belongs to the Flaviviridae family, genus Flavivirus and was first isolated 1947 in Uganda, Africa, from the serum of a sentinel Rhesus monkey. Since its discovery, the virus was responsible for major outbreaks in several different countries, being linked to severe complications in pregnant women, neonatal birth defects and the congenital zika syndrome. Maternal-fetal transmission of ZIKV can occur in all trimesters of pregnancy, and the role of the placenta and its cells in these cases is yet to be fully understood. The decidua basalis and chorionic villi, maternal-fetal components of the placenta, contain a rich immunological infiltrate composed by Hofbauer cells, mastocytes, dendritic cells and macrophages, primary cells of the innate immune response that have a role that still needs to be better investigated in ZIKV infection. Recent studies have already described several histopathological features and the susceptibility and permissiveness of placenta cells to infection by the Zika virus. In this review, we address some of the current knowledge on the innate immune responses against ZIKV, especially in the placenta.

Guillain-Barré Syndrome Following Zika Virus Infection Is Associated With a Diverse Spectrum of Peripheral Nerve Reactive Antibodies

BACKGROUND AND OBJECTIVES

Recent outbreaks of Zika virus (ZIKV) in South and Central America have highlighted significant neurologic side effects. Concurrence with the inflammatory neuropathy Guillain-Barré syndrome (GBS) is observed in 1:4,000 ZIKV cases. Whether the neurologic symptoms of ZIKV infection are immune mediated is unclear. We used rodent and human live cellular models to screen for anti-peripheral nerve reactive IgG and IgM autoantibodies in the sera of patients with ZIKV with and without GBS.

METHODS

In this study, 52 patients with ZIKV-GBS were compared with 134 ZIKV-infected patients without GBS and 91 non-ZIKV controls. Positive sera were taken forward for target identification by immunoprecipitation and mass spectrometry, and candidate antigens were validated by ELISA and cell-based assays. Autoantibody reactions against glycolipid antigens were also screened on an array.

RESULTS

Overall, IgG antibody reactivities to rat Schwann cells (SCs) (6.5%) and myelinated cocultures (9.6%) were significantly higher, albeit infrequent, in the ZIKV-GBS group compared with all controls. IgM antibody immunoreactivity to dorsal root ganglia neurones (32.3%) and SCs (19.4%) was more frequently observed in the ZIKV-GBS group compared with other controls, whereas IgM reactivity to cocultures was as common in ZIKV and non-ZIKV sera. Strong axonal-binding ZIKV-GBS serum IgG antibodies from 1 patient were confirmed to react with neurofascin 155 and 186. Serum from a ZIKV-infected patient without GBS displayed strong myelin-binding and putative antilipid antigen reaction characteristics. There was, however, no significant association of ZIKV-GBS with any known antiglycolipid antibodies.

DISCUSSION

Autoantibody responses in ZIKV-GBS target heterogeneous peripheral nerve antigens suggesting heterogeneity of the humoral immune response despite a common prodromal infection.

Case Report: Post-COVID-19 Vaccine Recurrence of Guillain–Barré Syndrome Following an Antecedent Parainfectious COVID-19–Related GBS

Guillain–Barré syndrome (GBS) is an autoimmune neurological disorder often preceded by viral illnesses or, more rarely, vaccinations. We report on a unique combination of postcoronavirus disease 2019 (COVID-19) vaccine GBS that occurred months after a parainfectious COVID-19–related GBS. Shortly after manifesting COVID-19 symptoms, a 57-year-old man developed diplopia, right-side facial weakness, and gait instability that, together with electrophysiology and cerebrospinal fluid examinations, led to a diagnosis of post-COVID-19 GBS. The involvement of cranial nerves and IgM seropositivity for ganglioside GD1b were noteworthy. COVID-19 pneumonia, flaccid tetraparesis, and autonomic dysfunction prompted his admission to ICU. He recovered after therapy with intravenous immunoglobulins (IVIg). Six months later, GBS recurred shortly after the first dose of the Pfizer/BioNTech vaccine. Again, the GBS diagnosis was confirmed by cerebrospinal fluid and electrophysiology studies. IgM seropositivity extended to multiple gangliosides, namely for GM3/4, GD1a/b, and GT1b IgM. An IVIg course prompted complete recovery. This case adds to other previously reported observations suggesting a possible causal link between SARS-CoV-2 and GBS. Molecular mimicry and anti-idiotype antibodies might be the underlying mechanisms. Future COVID-19 vaccinations/revaccinations in patients with previous para-/post-COVID-19 GBS deserve a reappraisal, especially if they are seropositive for ganglioside antibodies.

Polyclonal hyper immunoglobulin: A proven treatment and prophylaxis platform for passive immunization to address existing and emerging diseases

Passive immunization with polyclonal hyper immunoglobulin (HIG) therapy represents a proven strategy by transferring immunoglobulins to patients to confer immediate protection against a range of pathogens including infectious agents and toxins. Distinct from active immunization, the protection is passive and the immunoglobulins will clear from the system; therefore, administration of an effective dose must be maintained for prophylaxis or treatment until a natural adaptive immune response is mounted or the pathogen/agent is cleared. The current review provides an overview of this technology, key considerations to address different pathogens, and suggested improvements. The review will reflect on key learnings from development of HIGs in the response to public health threats due to Zika, influenza, and severe acute respiratory syndrome coronavirus 2.

Immunoglobulin and Monoclonal Antibody Therapies in Guillain-Barré Syndrome

Guillain-Barré syndrome (GBS) is an acute autoimmune polyradiculoneuropathy affecting 1-2 subjects per 100,000 every year worldwide. It causes, in its classic form, symmetric weakness in the proximal and distal limb muscles with common involvement of the cranial nerves, particularly facial weakness. Respiratory function is compromised in a case in four. Randomised controlled trials have demonstrated the benefit of therapeutic plasma exchange in hastening time to recovery. Intravenous immunoglobulin was subsequently shown to be as efficacious as plasma exchange in adult subjects. In children, few trials have shown the benefit of intravenous immunoglobulin versus supportive care. Pharmacokinetic studies suggested a relationship between increase in immunoglobulin G level post-infusion and outcome, implying administration of larger doses may be beneficial in subjects with poor prognosis. However, a subsequent trial of a second dose of immunoglobulin in such subjects failed to show improved outcome, while demonstrating a higher risk of thromboembolic side-effects. Monoclonal antibody therapy has more recently been investigated for GBS, after multiple studies in animal models, with different agents and variable postulated mechanisms of action. Eculizumab, a humanised monoclonal antibody against the complement protein C5, was tested in in two randomised, double-blind, placebo-controlled phase 2 trials. Neither showed benefit versus immunoglobulins alone on disability level at 4 weeks, although one study importantly suggested possible, clinically highly relevant, late effects on normalising function. A phase 3 trial is in progress. Preliminary results of a placebo-controlled ongoing study of ANX005, a humanised recombinant antibody against C1q inhibiting the complement cascade, have been promising.

New insights into the recombinant proteins and monoclonal antibodies employed to immunodiagnosis and control of Zika virus infection: A review

An emergent positive-stranded RNA virus, transmitted by mosquitoes with its first case of vertical transmission confirmed in 2015 in Brazil. The Zika virus (ZIKV) fever has received particular attention, mainly related to neurological diseases such as microcephaly in newborns. However, the laboratory diagnosis for ZIKV still faces some challenges due to its cross-reactivity with other flaviviruses, requiring a correct and differential diagnosis, contributing to the good prognosis of patients, especially in pregnant women. Among these, for early diagnosis, the CDC considers the RT-PCR the gold standard, more sensitive and specific, but expensive. Serological tests for the diagnosis of ZIKV can also be found beyond the period when the viral components are detectable in the serum. Inputs to produce more sensitive and specific diagnostic kits and the possibility of viral detection in less invasive samples are among the objectives of recent research on ZIKV. This review outlines recent advances in developing recombinant antigen and antibody-based diagnostic tools for the main flaviviruses in Northeast Brazil, such as ZIKV and Dengue virus (DENV).

Emerging Infection, Vaccination, and Guillain-Barré Syndrome: A Review

Guillain-Barré syndrome (GBS) is an autoimmune disorder of the peripheral nervous system that typically develops within 4 weeks after infection. In addition to conventional infectious diseases with which we are familiar, emerging infectious diseases, such as Zika virus infection and coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), have also been suggested to be associated with GBS. GBS is mainly categorized into a demyelinating subtype known as acute inflammatory demyelinating polyneuropathy (AIDP) and an axonal subtype known as acute motor axonal neuropathy (AMAN). Most patients who develop GBS after Zika virus infection or COVID-19 have AIDP. The concept of molecular mimicry between pathogens and human peripheral nerve components was established through studies of AMAN with anti-ganglioside GM1 antibodies occurring after Campylobacter jejuni infection. Although such mimicry between specific pathogens and myelin or Schwann cell components has not been clearly demonstrated in AIDP, a similarity of Zika virus and SARS-CoV-2 proteins to human proteins has been suggested. With the development of global commerce and travel, emerging infectious diseases will continue to threaten public health. From this viewpoint, the development of vaccines and antiviral drugs is important to prepare for and control emerging infectious diseases. Although a decrease in the number of patients after the 2015-2016 Zika epidemic increased the difficulty in conducting phase 3 trials for Zika virus vaccines, the efficacy and safety of new vaccines have recently been demonstrated for COVID-19. In general, vaccines can decrease the risk of infectious disease by stimulating the immune system, and discussions regarding an increased risk of autoimmune disorders, such as GBS, have been ongoing for many years. However, the risk of GBS is not considered a legitimate reason to limit the administration of currently available vaccines, as only a trivial association or no association with GBS has been demonstrated.

Clinical manifestations and health outcomes associated with Zika virus infections in adults: A systematic review

Background

Zika virus (ZIKV) has generated global interest in the last five years mostly due to its resurgence in the Americas between 2015 and 2016. It was previously thought to be a self-limiting infection causing febrile illness in less than one quarter of those infected. However, a rise in birth defects amongst children born to infected pregnant women, as well as increases in neurological manifestations in adults has been demonstrated. We systemically reviewed the literature to understand clinical manifestations and health outcomes in adults globally.

Methods

This review was registered prospectively with PROPSERO (CRD 42018096558). We systematically searched for studies in six databases from inception to the end of September 2020. There were no language restrictions. Critical appraisal was completed using the Joanna Briggs Institute Critical Appraisal Tools.

Findings

We identified 73 studies globally that reported clinical outcomes in ZIKV-infected adults, of which 55 studies were from the Americas. For further analysis, we considered studies that met 70% of critical appraisal criteria and described subjects with confirmed ZIKV. The most common symptoms included: exanthema (5,456/6,129; 89%), arthralgia (3,809/6,093; 63%), fever (3,787/6,124; 62%), conjunctivitis (2,738/3,283; 45%), myalgia (2,498/5,192; 48%), headache (2,165/4,722; 46%), and diarrhea (337/2,622; 13%). 36/14,335 (0.3%) of infected cases developed neurologic sequelae, of which 75% were Guillain-Barré Syndrome (GBS). Several subjects reported recovery from peak of neurological complications, though some endured chronic disability. Mortality was rare (0.1%) and hospitalization (11%) was often associated with co-morbidities or GBS.

Conclusions

The ZIKV literature in adults was predominantly from the Americas. The most common systemic symptoms were exanthema, fever, arthralgia, and conjunctivitis; GBS was the most prevalent neurological complication. Future ZIKV studies are warranted with standardization of testing and case definitions, consistent co-infection testing, reporting of laboratory abnormalities, separation of adult and pediatric outcomes, and assessing for causation between ZIKV and neurological sequelae.

Interest in Zika virus (ZIKV) has increased in the last decade due to its emergence and rapid spread in the Americas. In this review, we examine ZIKV clinical manifestations and sequelae in adults. Among studies reporting subjects with confirmed ZIKV and critical appraisal scores of at least 70%, symptoms reported include exanthema, fever, arthralgia, conjunctivitis, myalgia, headache, and diarrhea. Neurological sequelae in this group occurred in 0.3% of subjects, of which 75% were Guillain-Barré Syndrome (GBS). Recovery from GBS was variable: some patients returned to health and others endured chronic disability. Mortality was rare (0.1%). Hospitalization (11%) was often associated co-morbidities or GBS; this percentage perhaps reflects studies in which all reported subjects were hospitalized. Synthesizing reported data is challenging given the wide range of case definitions and ZIKV testing practices.

Mass Spectrometry versus Conventional Techniques of Protein Detection: Zika Virus NS3 Protease Activity towards Cellular Proteins

Mass spectrometry (MS) used in proteomic approaches is able to detect hundreds of proteins in a single assay. Although undeniable high analytical power of MS, data acquired sometimes lead to confusing results, especially during a search of very selective, unique interactions in complex biological matrices. Here, we would like to show an example of such confusing data, providing an extensive discussion on the observed phenomenon. Our investigations focus on the interaction between the Zika virus NS3 protease, which is essential for virus replication. This enzyme is known for helping to remodel the microenvironment of the infected cells. Several reports show that this protease can process cellular substrates and thereby modify cellular pathways that are important for the virus. Herein, we explored some of the targets of NS3, clearly shown by proteomic techniques, as processed during infection. Unfortunately, we could not confirm the biological relevance of protein targets for viral infections detected by MS. Thus, although mass spectrometry is highly sensitive and useful in many instances, also being able to show directions where cell/virus interaction occurs, we believe that deep recognition of their biological role is essential to receive complete insight into the investigated process.

A case series of parainfectious Guillain-Barré syndrome linked to influenza A (H1N1) virus infection

Guillain-Barré syndrome (GBS) is an immune-mediated peripheral neuropathy characterized by a typical post-infectious profile. Some post-Zika virus and post-severe acute respiratory syndrome-related coronavirus-2 GBS cases have been reported to occur with very short intervals between the infection and GBS onset. Evaluating 161 GBS patients consecutively admitted to two Italian Regional Hospitals between 2003 and 2019, we found that the only three with an antecedent influenza A (H1N1) virus infection developed GBS within an interval of less than 10 days from the influenza illness. The two of them with a demyelinating subtype promptly recovered without therapy. Overall, the parainfectious cases add heterogeneity to the GBS category, warranting pathogenetic insights.

Emerging infectious diseases, vaccines and Guillain-Barré syndrome

The recent outbreak of Zika virus infection increased the incidence of Guillain–Barré syndrome (GBS). Following the first reported case of GBS after Zika virus infection in 2013, there has been a considerable increase in the incidence of GBS in endemic countries, such as French Polynesia and Latin American countries. The association between coronavirus disease 2019 (COVID‐19), caused by the novel severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2), and GBS is another emerging research hotspot. Electrophysiological studies have suggested that GBS patients associated with Zika virus infection or COVID‐19 tend to manifest acute inflammatory demyelinating polyneuropathy, rather than acute motor axonal neuropathy (AMAN). Causative autoantibodies, such as anti‐ganglioside antibodies in AMAN associated with Campylobacter jejuni infection, have not been identified in GBS associated with these emerging infectious diseases. Nevertheless, recent studies suggested molecular mimicry between these viruses and human proteins related to GBS. Recent studies have shown the efficacy of new vaccines, containing artificial messenger RNA encoding the spike protein of SARS‐CoV‐2, against COVID‐19. These vaccines are now available in many countries and massive vaccination campaigns are currently ongoing. Although there are long‐standing concerns about the increased risk of GBS after inoculation of conventional vaccines, the risk of GBS is not considered a legitimate reason to limit administration of currently available vaccines, because the benefits outweigh the risks.

Anti-glycan antibodies: roles in human disease

Carbohydrate-binding antibodies play diverse and critical roles in human health. Endogenous carbohydrate-binding antibodies that recognize bacterial, fungal, and other microbial carbohydrates prevent systemic infections and help maintain microbiome homeostasis. Anti-glycan antibodies can have both beneficial and detrimental effects. For example, alloantibodies to ABO blood group carbohydrates can help reduce the spread of some infectious diseases, but they also impose limitations for blood transfusions. Antibodies that recognize self-glycans can contribute to autoimmune diseases, such as Guillain-Barre syndrome. In addition to endogenous antibodies that arise through natural processes, a variety of vaccines induce anti-glycan antibodies as a primary mechanism of protection. Some examples of approved carbohydrate-based vaccines that have had a major impact on human health are against pneumococcus, Haemophilus influeanza type b, and Neisseria meningitidis. Monoclonal antibodies specifically targeting pathogen associated or tumor associated carbohydrate antigens (TACAs) are used clinically for both diagnostic and therapeutic purposes. This review aims to highlight some of the well-studied and critically important applications of anti-carbohydrate antibodies.

Macrophages and Autoantibodies in Demyelinating Diseases

Myelin phagocytosis by macrophages has been an essential feature of demyelinating diseases in the central and peripheral nervous systems, including Guillain–Barré syndrome (GBS), chronic inflammatory demyelinating polyneuropathy (CIDP), and multiple sclerosis (MS). The discovery of autoantibodies, including anti-ganglioside GM1 antibodies in the axonal form of GBS, anti-neurofascin 155 and anti-contactin 1 antibodies in typical and distal forms of CIDP, and anti-aquaporin 4 antibodies in neuromyelitis optica, contributed to the understanding of the disease process in a subpopulation of patients conventionally diagnosed with demyelinating diseases. However, patients with these antibodies are now considered to have independent disease entities, including acute motor axonal neuropathy, nodopathy or paranodopathy, and neuromyelitis optica spectrum disorder, because primary lesions in these diseases are distinct from those in conventional demyelinating diseases. Therefore, the mechanisms underlying demyelination caused by macrophages remain unclear. Electron microscopy studies revealed that macrophages destroy myelin as if they are the principal players in the demyelination process. Recent studies suggest that macrophages seem to select specific sites of myelinated fibers, including the nodes of Ranvier, paranodes, and internodes, for the initiation of demyelination in individual cases, indicating that specific components localized to these sites play an important role in the behavior of macrophages that initiate myelin phagocytosis. Along with the search for autoantibodies, the ultrastructural characterization of myelin phagocytosis by macrophages is a crucial step in understanding the pathophysiology of demyelinating diseases and for the future development of targeted therapies.

Guillain-Barré syndrome

Guillain-Barré syndrome is the most common cause of acute flaccid paralysis worldwide. Most patients present with an antecedent illness, most commonly upper respiratory tract infection, before the onset of progressive motor weakness. Several microorganisms have been associated with Guillain-Barré syndrome, most notably Campylobacter jejuni, Zika virus, and in 2020, the severe acute respiratory syndrome coronavirus 2. In C jejuni-related Guillain-Barré syndrome, there is good evidence to support an autoantibody-mediated immune process that is triggered by molecular mimicry between structural components of peripheral nerves and the microorganism. Making a diagnosis of so-called classical Guillain-Barré syndrome is straightforward; however, the existing diagnostic criteria have limitations and can result in some variants of the syndrome being missed. Most patients with Guillain-Barré syndrome do well with immunotherapy, but a substantial proportion are left with disability, and death can occur. Results from the International Guillain-Barré Syndrome Outcome Study suggest that geographical variations exist in Guillain-Barré syndrome, including insufficient access to immunotherapy in low-income countries. There is a need to provide improved access to treatment for all patients with Guillain-Barré syndrome, and to develop effective disease-modifying therapies that can limit the extent of nerve injury. Clinical trials are currently underway to investigate some of the potential therapeutic candidates, including complement inhibitors, which, together with emerging data from large international collaborative studies on the syndrome, will contribute substantially to understanding the many facets of this disease.

Stem-cell-derived human microglia transplanted into mouse brain to study human disease

Microglia are critically involved in complex neurological disorders with a strong genetic component, such as Alzheimer's disease, Parkinson's disease and frontotemporal dementia. Although mouse microglia can recapitulate aspects of human microglia physiology, they do not fully capture the human genetic aspects of disease and do not reproduce all human cell states. Primary cultures of human microglia or microglia derived from human induced pluripotent stem cells (PSCs) are difficult to maintain in brain-relevant cell states in vitro. Here we describe MIGRATE (microglia in vitro generation refined for advanced transplantation experiments, which provides a combined in vitro differentiation and in vivo xenotransplantation protocol to study human microglia in the context of the mouse brain. This article details an accurate, step-by-step workflow that includes in vitro microglia differentiation from human PSCs, transplantation into the mouse brain and quantitative analysis of engraftment. Compared to current differentiation and xenotransplantation protocols, we present an optimized, faster and more efficient approach that yields up to 80% chimerism. To quantitatively assess engraftment efficiency by flow cytometry, access to specialized flow cytometry is required. Alternatively, the percentage of chimerism can be estimated by standard immunohistochemical analysis. The MIGRATE protocol takes ~40 d to complete, from culturing PSCs to engraftment efficiency assessment.

Zika Virus Infection Leads to Demyelination and Axonal Injury in Mature CNS Cultures

Understanding how Zika virus (Flaviviridae; ZIKV) affects neural cells is paramount in comprehending pathologies associated with infection. Whilst the effects of ZIKV in neural development are well documented, impact on the adult nervous system remains obscure. Here, we investigated the effects of ZIKV infection in established mature myelinated central nervous system (CNS) cultures. Infection incurred damage to myelinated fibers, with ZIKV-positive cells appearing when myelin damage was first detected as well as axonal pathology, suggesting the latter was a consequence of oligodendroglia infection. Transcriptome analysis revealed host factors that were upregulated during ZIKV infection. One such factor, CCL5, was validated in vitro as inhibiting myelination. Transferred UV-inactivated media from infected cultures did not damage myelin and axons, suggesting that viral replication is necessary to induce the observed effects. These data show that ZIKV infection affects CNS cells even after myelination-which is critical for saltatory conduction and neuronal function-has taken place. Understanding the targets of this virus across developmental stages including the mature CNS, and the subsequent effects of infection of cell types, is necessary to understand effective time frames for therapeutic intervention.

Burden of Disease of Guillain-Barré Syndrome in Brazil before and during the Zika virus epidemic 2014-2016

OBJECTIVE

To estimate the burden of disease of Guillain-Barré syndrome (GBS) in Brazil in 2014, 1 year before the Zika virus epidemic, and in 2015 and 2016 during the epidemic.

METHODS

The burden of disease of GBS was estimated using the summary measure of population health: Disability Adjusted Life Years (DALY), that combines both mortality (Years of Life Lost YLLs) and morbidity (Years Lived with Disability) components. The study population was composed of GBS hospitalised cases and deaths from the information systems of the Brazilian Unified Health System.

RESULTS

The GBS incidence rate in 2014, 2015 and 2016 was 0.74, 0.96, 1.02/100 000 respectively, and the mortality rate in the same period was 0.08, 0.009 and 0.11/100 000 habitants. The DALYs calculated using the point estimate of GBS disability weight and its values of the confidence interval (0.198 and 0.414) were 5725.90 (5711.79-5742.89) in 2014, 6054.61 (6035.57-6077.54) in 2015 and 7588.49 (7570.20-7610.51) in 2016. The DALYs were high among the male population and in age groups between 20 and 50 years.

CONCLUSIONS

The increase in DALYs in the years 2015 and 2016 compared to 2014 probably resulted from the introduction of ZIKV in Brazil, reinforcing the importance of investments in the prevention of ZIKV infection and in the care of GBS patients.

Guillain-Barré syndrome associated with SARS-CoV-2 infection: A systematic review and individual participant data meta-analysis

Several published reports have described a possible association between Guillain-Barré syndrome (GBS) and severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infection. This systematic review aimed to summarize and meta-analyze the salient features and prognosis of SARS-CoV-2-associated GBS. We searched the PubMed (Medline), Web of Science and Cochrane databases for articles published between 01 January 2020 and 05 August 2020 using SARS-CoV-2 and GBS-related keywords. Data on sociodemographic characteristics, antecedent symptoms, clinical, serological and electrophysiological features, and hospital outcomes were recorded. We included 45 articles from 16 countries reporting 61 patients with SARS-CoV-2-associated GBS. Most (97.7%) articles were from high- and upper-middle-income countries. Forty-two (68.9%) of the patients were male; median (interquartile range) age was 57 (49-70) years. Reverse transcriptase polymerase chain reaction for SARS-CoV-2 was positive in 90.2% of patients. One report of SARS-CoV-2-associated familial GBS was found which affected a father and daughter of a family. Albuminocytological dissociation in cerebrospinal fluid was found in 80.8% of patients. The majority of patients (75.5%) had a demyelinating subtype of GBS. Intravenous immunoglobulin and plasmapheresis were given to 92.7% and 7.3% of patients, respectively. Around two-thirds (65.3%) of patients had a good outcome (GBS-disability score ≤ 2) on discharge from hospital. Two patients died in hospital. SARS-CoV-2-associated GBS mostly resembles the classical presentations of GBS that respond to standard treatments. Extensive surveillance is required in low- and lower-middle-income countries to identify and report similar cases/series. Further large-scale case-control studies are warranted to strengthen the current evidence. PROSPERO Registration Number CRD42020201673.

Abnormal antibodies to self-carbohydrates in SARS-CoV-2 infected patients

SARS-CoV-2 is a deadly virus that is causing the global pandemic coronavirus disease 2019 (COVID-19). Our immune system plays a critical role in preventing, clearing, and treating the virus, but aberrant immune responses can contribute to deleterious symptoms and mortality. Many aspects of immune responses to SARS-CoV-2 are being investigated, but little is known about immune responses to carbohydrates. Since the surface of the virus is heavily glycosylated, pre-existing antibodies to glycans could potentially recognize the virus and influence disease progression. Furthermore, antibody responses to carbohydrates could be induced, affecting disease severity and clinical outcome. In this study, we used a carbohydrate antigen microarray with over 800 individual components to profile serum anti-glycan antibodies in COVID-19 patients and healthy control subjects. In COVID-19 patients, we observed abnormally high IgG and IgM antibodies to numerous self-glycans, including gangliosides, N -linked glycans, LacNAc-containing glycans, blood group H, and sialyl Lewis X. Some of these anti-glycan antibodies are known to play roles in autoimmune diseases and neurological disorders, which may help explain some of the unusual and prolonged symptoms observed in COVID-19 patients. The detection of antibodies to self-glycans has important implications for using convalescent serum to treat patients, developing safe and effective SARS-CoV-2 vaccines, and understanding the risks of infection. In addition, this study provides new insight into the immune responses to SARS-CoV-2 and illustrates the importance of including host and viral carbohydrate antigens when studying immune responses to viruses.

Managing disease outbreaks: The importance of vector mobility and spatially heterogeneous control

Management strategies for control of vector-borne diseases, for example Zika or dengue, include using larvicide and/or adulticide, either through large-scale application by truck or plane or through door-to-door efforts that require obtaining permission to access private property and spray yards. The efficacy of the latter strategy is highly dependent on the compliance of local residents. Here we develop a model for vector-borne disease transmission between mosquitoes and humans in a neighborhood setting, considering a network of houses connected via nearest-neighbor mosquito movement. We incorporate large-scale application of adulticide via aerial spraying through a uniform increase in vector death rates in all sites, and door-to-door application of larval source reduction and adulticide through a decrease in vector emergence rates and an increase in vector death rates in compliant sites only, where control efficacies are directly connected to real-world experimentally measurable control parameters, application frequencies, and control costs. To develop mechanistic insight into the influence of vector motion and compliance clustering on disease controllability, we determine the basic reproduction number R0 for the system, provide analytic results for the extreme cases of no mosquito movement, infinite hopping rates, and utilize degenerate perturbation theory for the case of slow but non-zero hopping rates. We then determine the application frequencies required for each strategy (alone and combined) in order to reduce R0 to unity, along with the associated costs. Cost-optimal strategies are found to depend strongly on mosquito hopping rates, levels of door-to-door compliance, and spatial clustering of compliant houses, and can include aerial spray alone, door-to-door treatment alone, or a combination of both. The optimization scheme developed here provides a flexible tool for disease management planners which translates modeling results into actionable control advice adaptable to system-specific details.

Clinical neurophysiology and cerebrospinal liquor analysis to detect Guillain-Barré syndrome and polyneuritis cranialis in COVID-19 patients: A case series

We report a case series of five patients affected by SARS‐CoV‐2 who developed neurological symptoms, mainly expressing as polyradiculoneuritis and cranial polyneuritis in the 2 months of COVID‐19 pandemic in a city in the northeast of Italy. A diagnosis of Guillain‐Barré syndrome was made on the basis of clinical presentation, cerebrospinal fluid analysis, and electroneurography. In four of them, the therapeutic approach included the administration of intravenous immunoglobulin (0.4 g/kg for 5 days), which resulted in the improvement of neurological symptoms. Clinical neurophysiology revealed the presence of conduction block, absence of F waves, and in two cases a significant decrease in amplitude of compound motor action potential compound muscle action potential (cMAP). Four patients presented a mild facial nerve involvement limited to the muscles of the lower face, with sparing of the forehead muscles associated to ageusia. In one patient, taste assessment showed right‐sided ageusia of the tongue, ipsilateral to the mild facial palsy. In three patients we observed albuminocytological dissociation in the cerebrospinal fluid, and notably, we found an increase of inflammatory mediators such as the interleukin‐8. Peripheral nervous system involvement after infection with COVID‐19 is possible and may include several signs that may be successfully treated with immunoglobulin therapy.

Neurological symptoms may be common in COVID‐19 patients

Neurophysiological assessment is fundamental for a correct diagnosis

Peripheral nervous system involvement is possibile in people with COVID‐19

In these patients, intravenous immunoglobulin administration is a safe and efficient therapy

The Association of Anti-Ganglioside Antibodies in the Pathogenesis and Development of Zika-Associated Guillain-Barré Syndrome

Zika virus (ZIKV) has created major outbreaks all over the Americas and has caused severe neurological complications. The main neurological complications linked to ZIKV are Guillain-Barré syndrome (GBS), encephalitis, myelitis, and microcephaly. We thoroughly searched for published literature on PubMed and found evidence supporting the relationship between ZIKV and GBS. Through April 1, 2020, 429 publications were available on PubMed using the words “Zika associated GBS.” Among these, only four results linked anti-ganglioside antibodies to Zika-associated GBS. So, we expanded our search to other platforms like PubMed Central® (PMC), Google Scholar, and Cochrane, after which we shortlisted 28 studies. These studies include review articles, observational studies, case series, and case reports. The information collected from these articles were mainly based on the outbreaks in Latin America and the results that these patients showed in the course of the disease. It took a lag time of 7-10 days for the patients to develop Zika-associated GBS. We used all the evidence regarding the epidemiology, clinical manifestations, neurological complications, and diagnostic criteria that supported the findings of anti-ganglioside antibodies to ZIKV-associated GBS. Patients were detected with the presence of these antibodies in their urine through the enzyme-linked immunosorbent assay (ELISA) test. But the mechanism by which the ZIKV causes other complications like myelitis and encephalitis is still unknown and yet to be explored to develop treatment and management strategies.

Ultrastructural mechanisms of macrophage-induced demyelination in Guillain-Barré syndrome

OBJECTIVE

To describe the pathological features of Guillain-Barré syndrome focusing on macrophage-associated myelin lesions.

METHODS

Longitudinal sections of sural nerve biopsy specimens from 11 patients with acute inflammatory demyelinating polyneuropathy (AIDP) exhibiting macrophage-associated demyelinating lesions were examined using electron microscopy. A total of 1205 nodes of Ranvier were examined to determine the relationship of the macrophage-associated demyelinating lesions with the nodal regions. Additionally, immunohistochemical and immunofluorescent studies were performed to elucidate the sites of complement deposition.

RESULTS

Overall, 252 macrophage-associated myelin lesions were identified in longitudinal sections. Of these, 40 lesions exhibited complete demyelination with no association with the lamellar structures of myelin. In 183 lesions, macrophage cytoplasm was located at internodes without association with the nodes of Ranvier or paranodes. In particular, these internodal lesions were more frequent in one patient (152 lesions). In the remaining 29 lesions, the involvement of nodal regions was obvious. Lesions involving nodal regions were more frequently observed than those involving internodes in four patients. Invasion of the macrophage cytoplasmic processes into the space between the paranodal myelin terminal loops and the axolemma from the nodes of Ranvier was observed in three of these patients. Immunostaining suggested complement deposition corresponding to putative initial macrophage-associated demyelinating lesions.

CONCLUSIONS

The initial macrophage-associated demyelinating lesions appeared to be located at internodes and at nodal regions. The sites at which the macrophages initiated phagocytosis of myelin might be associated with the location of complement deposition in certain patients with AIDP.

Early Guillain-Barré syndrome in coronavirus disease 2019 (COVID-19): a case report from an Italian COVID-hospital

Guillain-Barré syndrome (GBS) is an acute polyradiculoneuropathy associated with dysimmune processes, often related to a previous infectious exposure. During Italian severe acute respiratory syndrome coronavirus-2 outbreak, a woman presented with a rapidly progressive flaccid paralysis with unilateral facial neuropathy after a few days of mild respiratory symptoms. Coronavirus was detected by nasopharyngeal swab, but there was no evidence of its presence in her cerebrospinal fluid, which confirmed the typical albumin-cytological dissociation of GBS, along with consistent neurophysiological data. Despite immunoglobulin infusions and intensive supportive care, her clinical picture worsened simultaneously both from the respiratory and neurological point of view, as if reflecting different aspects of the same systemic inflammatory response. Similar early complications have already been observed in patients with para-infectious GBS related to Zika virus, but pathological mechanisms have yet to be established.

Militão de Albuquerque MDF. Guillain-Barré syndrome related to Zika virus infection: A systematic review and meta-analysis of the clinical and electrophysiological phenotype

Background

The Zika virus (ZIKV) has been associated with Guillain-Barré syndrome (GBS) in epidemiological studies. Whether ZIKV-associated GBS is related to a specific clinical or electrophysiological phenotype has not been established. To this end, we performed a systematic review and meta-analysis of all published studies on ZIKV-related GBS.

Methods

We searched Pubmed, EMBASE and LILACS, and included all papers, reports or bulletins with full text in English, Spanish or Portuguese, reporting original data of patients with GBS and a suspected, probable or confirmed recent ZIKV infection. Data were extracted according to a predefined protocol, and pooled proportions were calculated.

Results

Thirty-five studies were included (13 single case reports and 22 case series, case-control or cohort studies), reporting on a total of 601 GBS patients with a suspected, probable or confirmed ZIKV infection. Data from 21 studies and 587 cases were available to be summarized. ZIKV infection was confirmed in 21%, probable in 22% and suspected in 57% of cases. ZIKV PCR was positive in 30% (95%CI 15–47) of tested patients. The most common clinical features were: limb weakness 97% (95%CI 93–99), diminished/absent reflexes 96% (95%CI 88–100), sensory symptoms 82% (95%CI 76–88), and facial palsy 51% (95%CI 44–58). Median time between infectious and neurological symptoms was 5–12 days. Most cases had a demyelinating electrophysiological subtype and half of cases were admitted to the Intensive Care Unit (ICU). Heterogeneity between studies was moderate to substantial for most variables.

Conclusions

The clinical phenotype of GBS associated with ZIKV infection reported in literature is generally a sensorimotor demyelinating GBS with frequent facial palsy and a severe disease course often necessitating ICU admittance. Time between infectious and neurological symptoms and negative PCR in most cases suggests a post-infectious disease mechanism. Heterogeneity between studies was considerable and results may be subject to reporting bias. This study was registered on the international Prospective Register of Systematic Reviews (CRD42018081959).

Guillain-Barré syndrome (GBS) is a rare but severe neurological disease, characterized by an acute onset flaccid paralysis. GBS is thought to be caused by an exaggerated immune response to common infections that damages the peripheral nerves. The Zika virus (ZIKV) is the most recent pathogen to be connected to GBS, when large outbreaks of ZIKV infection in French Polynesia and Latin America were followed by an increased incidence of GBS patients. To better understand the clinical features and outcome of ZIKV-related GBS, we have performed a systematic review and meta-analysis of all published studies on GBS related to ZIKV. We identified 35 studies, reporting on a total of 601 patients with GBS and a suspected, probable or confirmed Zika virus infection, and were able to summarize data of 587 patients from 21 studies in a pooled analysis. Our study shows that published cases with ZIKV-related GBS generally have both sensory and motor symptoms, facial palsy, demyelination on electrophysiological examination, and a severe disease course that often necessitates ICU admittance. The relatively long time between infectious and neurologic symptoms and the lack of detection of viral particles in bodily fluids in most patients suggest a post-infectious rather than an infectious pathogenesis. However, these results should be interpreted taking into account the heterogeneity between studies, which was considerable for many variables, and a possible reporting bias of more severe cases. Outbreaks of ZIKV and GBS may appear in the future and our study can help clinicians in diagnosing and managing GBS patients in ZIKV endemic areas, and increases our understanding of the neuropathology of ZIKV.

Human iPSC-derived microglia: A growing toolset to study the brain's innate immune cells

Recent advances in the generation of microglia from human induced pluripotent stem cells (iPSCs) have provided exciting new approaches to examine and decipher the biology of microglia. As these techniques continue to evolve to encompass more complex in situ and in vivo paradigms, so too have they begun to yield novel scientific insight into the genetics and function of human microglia. As such, researchers now have access to a toolset comprised of three unique "flavors" of iPSC-derived microglia: in vitro microglia (iMGs), organoid microglia (oMGs), and xenotransplanted microglia (xMGs). The goal of this review is to discuss the variety of research applications that each of these techniques enables and to highlight recent discoveries that these methods have begun to uncover. By presenting the research paradigms in which each model has been successful, as well as the key benefits and limitations of each approach, it is our hope that this review will help interested researchers to incorporate these techniques into their studies, collectively advancing our understanding of human microglia biology.

An antibiotic depleted microbiome drives severe Campylobacter jejuni-mediated Type 1/17 colitis, Type 2 autoimmunity and neurologic sequelae in a mouse model

The peripheral neuropathy Guillain-Barré Syndrome can follow Campylobacter jejuni infection when outer core lipooligosaccharides induce production of neurotoxic anti-ganglioside antibodies. We hypothesized that gut microbiota depletion with an antibiotic would increase C. jejuni colonization, severity of gastroenteritis, and GBS. Microbiota depletion increased C. jejuni colonization, invasion, and colitis with Type 1/17 T cells in gut lamina propria. It also stimulated Type 1/17 anti-C. jejuni and -antiganglioside-antibodies, Type 2 anti-C. jejuni and -antiganglioside antibodies, and neurologic phenotypes. Results indicate that both C. jejuni strain and gut microbiota affect development of inflammation and GBS and suggest that probiotics following C. jejuni infection may ameliorate inflammation and autoimmune disease.

Zika Virus and Neurologic Disease

Zika virus (ZIKV) is an arthropod-borne virus that belongs to the Flaviviridae family. Although most cases are mild or go undetected, rare severe neurologic effects, including congenital ZIKV syndrome (CZS) and Guillain-Barré syndrome, have been identified. The serious neurologic complications associated with ZIKV prompted the declaration of the public health emergency of international concern by the World Health Organization. Overall, transmission occurred throughout South and Central America as well as the Caribbean, affecting 48 countries and territories from March 2015 to March 2017. Long-term management of CZS requires a comprehensive combination of supportive services throughout early development.

Long-term outcome in neuroZika

Objective

To characterize the full spectrum, relative frequency, and prognosis of the neurologic manifestations in Zika virus (ZIKV) postnatal infection.

Methods

We conducted an observational study in consecutive ZIKV-infected patients presenting with neurologic manifestations during the French West Indies 2016 outbreak.

Results

Eighty-seven patients, including 6 children, were enrolled. Ninety-five percent of all cases required hospitalization. Guillain-Barré syndrome was the most frequent manifestation (46.0%) followed by encephalitis or encephalomyelitis (20.7%), isolated single or multiple cranial nerve palsies (9.2%), other peripheral manifestations (6.9%), and stroke (1.1%). Fourteen patients (16.1%), including one child, developed a mixed disorder involving both the central and peripheral nervous system. Mechanical ventilation was required in 21 cases, all of whom had ZIKV RNA in at least one biological fluid. Two adult patients died due to neuroZika. Clinical follow-up (median 14 months; interquartile range, 13–17 months) was available for 76 patients. Residual disability (modified Rankin Scale score ≥2) was identified in 19 (25.0%) patients; in 6 cases (7.9%), disability was severe (modified Rankin Scale score ≥4). Among patients with ZIKV RNA detected in one biological fluid, the risk of residual disability or death was higher (odds ratio 9.19; confidence interval 1.12–75.22; p = 0.039).

Conclusions

NeuroZika spectrum represents a heterogeneous group of clinical neurologic manifestations. During an outbreak, clinicians should consider neuroZika in patients presenting with cranial nerve palsies and a mixed neurologic disorder. Long-term sequelae are frequent in NeuroZika. ZIKV reverse-transcription PCR status at admission can inform prognosis and should therefore be taken into consideration in the management of hospitalized patients.

Neurological Implications of Zika Virus Infection in Adults

The 2015-2016 epidemic of Zika virus (ZIKV) in the Americas and the Caribbean was associated with an unprecedented burden of neurological disease among adults. Clinically, Guillain-Barre syndrome (GBS) predominated among regions affected by the ZIKV epidemic, but the spectrum of neurological disease in the adults appears broader as cases of encephalopathy, encephalitis, meningitis, myelitis, and seizures have also been reported. A para-infectious temporal profile of ZIKV-associated GBS (ZIKV-GBS) has been described in clinical studies, which may suggest a direct viral neuropathic effect. However, ZIKV neuropathogenesis has not yet been fully understood. Mechanisms for ZIKV-GBS and other neurological syndromes have been hypothesized, such as adaptive viral genetic changes, immunological interactions with other circulating flaviviruses, and host and factors. This review summarizes the current evidence on ZIKV-associated neurological complications in the adults.

Clinical Features of Guillain-Barré Syndrome With vs Without Zika Virus Infection, Puerto Rico, 2016

Importance

The pathophysiologic mechanisms of Guillain-Barré syndrome (GBS) associated with Zika virus (ZIKV) infection may be indicated by differences in clinical features.

Objective

To identify specific clinical features of GBS associated with ZIKV infection.

Design, Setting, and Participants

During the ZIKV epidemic in Puerto Rico, prospective and retrospective strategies were used to identify patients with GBS who had neurologic illness onset in 2016 and were hospitalized at all 57 nonspecialized hospitals and 2 rehabilitation centers in Puerto Rico. Guillain-Barré syndrome diagnosis was confirmed via medical record review using the Brighton Collaboration criteria. Specimens (serum, urine, cerebrospinal fluid, and saliva) from patients with GBS were tested for evidence of ZIKV infection by real-time reverse transcriptase-polymerase chain reaction; serum and cerebrospinal fluid were also tested by IgM enzyme-linked immunosorbent assay. In this analysis of public health surveillance data, a total of 123 confirmed GBS cases were identified, of which 107 had specimens submitted for testing; there were 71 patients with and 36 patients without evidence of ZIKV infection. Follow-up telephone interviews with patients were conducted 6 months after neurologic illness onset; 60 patients with and 27 patients without evidence of ZIKV infection participated.

Main Outcomes and Measures

Acute and long-term clinical characteristics of GBS associated with ZIKV infection.

Results

Of 123 patients with confirmed GBS, the median age was 54 years (age range, 4-88 years), and 68 patients (55.3%) were male. The following clinical features were more frequent among patients with GBS and evidence of ZIKV infection compared with patients with GBS without evidence of ZIKV infection: facial weakness (44 [62.0%] vs 10 [27.8%]; P < .001), dysphagia (38 [53.5%] vs 9 [25.0%]; P = .005), shortness of breath (33 [46.5%] vs 9 [25.0%]; P = .03), facial paresthesia (13 [18.3%] vs 1 [2.8%]; P = .03), elevated levels of protein in cerebrospinal fluid (49 [94.2%] vs 23 [71.9%]; P = .008), admission to the intensive care unit (47 [66.2%] vs 16 [44.4%]; P = .03), and required mechanical ventilation (22 [31.0%] vs 4 [11.1%]; P = .02). Six months after neurologic illness onset, patients with GBS and evidence of ZIKV infection more frequently reported having excessive or inadequate tearing (30 [53.6%] vs 6 [26.1%]; P = .03), difficulty drinking from a cup (10 [17.9%] vs 0; P = .03), and self-reported substantial pain (15 [27.3%] vs 1 [4.3%]; P = .03).

Conclusions and Relevance

In this study, GBS associated with ZIKV infection was found to have higher morbidity during the acute phase and more frequent cranial neuropathy during acute neuropathy and 6 months afterward. Results indicate GBS pathophysiologic mechanisms that may be more common after ZIKV infection.

Point-of-care diagnostic assay for the detection of Zika virus using the recombinase polymerase amplification method

The sudden and explosive expansion of Zika virus (ZIKV) from the African continent through Oceania and culminating in the outbreak in South America has highlighted the importance of new rapid point-of-care diagnostic tools for the control and prevention of transmission. ZIKV infection has devastating consequences, such as neurological congenital malformations in infants born to infected mothers and Guillain-Barré syndrome in adults. Additionally, its potential for transmission through vector bites, as well as from person to person through blood transfusions and sexual contact, are important considerations for prompt diagnosis. Recombinase polymerase amplification (RPA), an isothermal method, was developed as an alternative field-applicable assay to PCR. Here we report the development of a novel ZIKV real-time reverse transcriptase RPA (RT-RPA) assay capable of detecting a range of different ZIKV strains from a variety of geographical locations. The ZIKV RT-RPA was shown to be highly sensitive, being capable of detecting as few as five copies of target nucleic acid per reaction, and suitable for use with a battery-operated portable device. The ZIKV RT-RPA demonstrated 100 % specificity and 83 % sensitivity in clinical samples. Furthermore, we determined that the ZIKV RT-RPA is a versatile assay that can be applied to crude samples, such as saliva and serum, and can be used as a vector surveillance tool on crude mosquito homogenates. Therefore, the developed ZIKV RT-RPA is a useful diagnostic tool that can be transferred to a resource-limited location, eliminating the need for a specialized and sophisticated laboratory environment and highly trained staff.

Postmortem Findings in Patient with Guillain-Barré Syndrome and Zika Virus Infection

Postmortem examination results of a patient with Guillain-Barré syndrome and confirmed Zika virus infection revealed demyelination of the sciatic and cranial IV nerves, providing evidence of the acute demyelinating inflammatory polyneuropathy Guillain-Barré syndrome variant. Lack of evidence of Zika virus in nervous tissue suggests that pathophysiology was antibody mediated without neurotropism.

Neuroimaging Findings of Zika Virus-Associated Neurologic Complications in Adults

When the first suspected cases of neurologic disorders associated with the Zika virus were noticed in Brazil in late 2015, several studies had been conducted to understand the pathophysiology of the disease and its associated complications. In addition to its well-established association with microcephaly in neonates, the Zika virus infection has also been suggested to trigger other severe neurologic complications in adults, such as Guillain-Barré syndrome, radiculomyelitis, and meningoencephalitis. Hence, the Zika virus should be deemed a global threat that can cause devastating neurologic complications among individuals in all age ranges. The aim of this review was to further describe neuroimaging findings of Zika virus infection and associated neurologic complications found in adults.

Identification of CSF biomarkers by proteomics in Guillain-Barré syndrome

The purpose of the present study was to screen for differentially expressed proteins in the cerebrospinal fluid (CSF) of patients with Guillain-Barré syndrome (GBS). The identification of differentially expressed protein can provide new targets for understanding the pathogenic mechanism, early clinical diagnosis, prognosis and for measuring the effectiveness of interventions. We enrolled 50 GBS patients and 50 meningitis patients (control group) to compare protein expression in CSF. The GBS cases included 28 cases of acute inflammatory demyelinating polyneuropathy (AIDP) and 22 cases of acute motor axonal neuropathy (AMAN). We then performed two-dimensional differential in-gel electrophoresis combined with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry to identify the differentially expressed proteins. The expression levels were validated by ELISA, and their accuracy, sensitivity, and specificity in GBS diagnosis were analyzed by the receiver operating characteristic curve. Three differentially expressed proteins were identified, including the upregulated haptoglobin (Hp) and heat shock protein 70 (Hsp70), and downregulated cystatin C. There were no significant differences between the AIDP and AMAN patients in the positive rates and quantitative expression levels of the three differentially expressed proteins. The accuracy of Hp in the diagnosis of GBS was 0.835, sensitivity was 86.7%, and specificity was 88.2%. The accuracy of cystatin C in the diagnosis of GBS was 0.827, sensitivity was 85.5%, and specificity was 89.7%. The accuracy of Hsp70 in the diagnosis of GBS was 0.841, its sensitivity was 87.8%, and its specificity was 92.3%. Hp and Hsp70 are significantly increased, and cystatin C is downregulated in CSF of GBS patients, which provides important biomarkers for early GBS diagnosis, although these proteins cannot distinguish AIDP and AMAN.