Antigenic differences between AS03 adjuvanted influenza A (H1N1) pandemic vaccines: implications for pandemrix-associated narcolepsy risk

Avian Influenza Virus A(H5Nx) and Prepandemic Candidate Vaccines: State of the Art

Avian influenza virus has been long considered the main threat for a future pandemic. Among the possible avian influenza virus subtypes, A(H5N1) clade 2.3.4.4b is becoming enzootic in mammals, representing an alarming step towards a pandemic. In particular, genotype B3.13 has recently caused an outbreak in US dairy cattle. Since pandemic preparedness is largely based on the availability of prepandemic candidate vaccine viruses, in this review we will summarize the current status of the enzootics, and challenges for H5 vaccine manufacturing and delivery.

Downregulation of hypocretin/orexin after H1N1 Pandemrix vaccination of adolescent mice

Narcolepsy type 1 (NT1), characterized by the loss of hypocretin/orexin (HCRT) production in the lateral hypothalamus, has been linked to Pandemrix vaccination during the 2009 H1N1 pandemic, especially in children and adolescents. It is still unknown why this vaccination increased the risk of developing NT1. This study investigated the effects of Pandemrix vaccination during adolescence on Hcrt mRNA expression in mice. Mice received a primary vaccination (50 µL i.m.) during prepubescence and a booster vaccination during peri-adolescence. Hcrt expression was measured at three-time points after the vaccinations. Control groups included both a saline group and an undisturbed group of mice. Hcrt expression was decreased after both Pandemrix and saline injections, but 21 days after the second injection, the saline group no longer showed decreased Hcrt expression, while the Pandemrix group still exhibited a significant reduction of about 60% compared to the undisturbed control group. This finding suggests that Pandemrix vaccination during adolescence influences Hcrt expression in mice into early adulthood. The Hcrt mRNA level did not reach the low levels known to induce NT1 symptoms, instead, our finding supports the multiple-hit hypothesis of NT1 that states that several insults to the HCRT system may be needed to induce NT1 and that Pandemrix could be one such insult.

Regulation of PaRBOH1-mediated ROS production in Norway spruce by Ca2+ binding and phosphorylation

Plant respiratory burst oxidase homologs (RBOHs) are plasma membrane-localized NADPH oxidases that generate superoxide anion radicals, which then dismutate to H₂O₂, into the apoplast using cytoplasmic NADPH as an electron donor. PaRBOH1 is the most highly expressed RBOH gene in developing xylem as well as in a lignin-forming cell culture of Norway spruce (Picea abies L. Karst.). Since no previous information about regulation of gymnosperm RBOHs exist, our aim was to resolve how PaRBOH1 is regulated with a focus on phosphorylation. The N-terminal part of PaRBOH1 was found to contain several putative phosphorylation sites and a four-times repeated motif with similarities to the Botrytis-induced kinase 1 target site in Arabidopsis AtRBOHD. Phosphorylation was indicated for six of the sites in in vitro kinase assays using 15 amino-acid-long peptides for each of the predicted phosphotarget site in the presence of protein extracts of developing xylem. Serine and threonine residues showing positive response in the peptide assays were individually mutated to alanine (kinase-inactive) or to aspartate (phosphomimic), and the wild type PaRBOH1 and the mutated constructs transfected to human kidney embryogenic (HEK293T) cells with a low endogenous level of extracellular ROS production. ROS-producing assays with HEK cells showed that Ca²⁺ and phosphorylation synergistically activate the enzyme and identified several serine and threonine residues that are likely to be phosphorylated including a novel phosphorylation site not characterized in other plant species. These were further investigated with a phosphoproteomic study. Results of Norway spruce, the first gymnosperm species studied in relation to RBOH regulation, show that regulation of RBOH activity is conserved among seed plants.

Narcolepsy and H1N1 influenza immunology a decade later: What have we learned?

In the wake of the A/California/7/2009 H1N1 influenza pandemic vaccination campaigns in 2009-2010, an increased incidence of the chronic sleep-wake disorder narcolepsy was detected in children and adolescents in several European countries. Over the last decade, in-depth epidemiological and immunological studies have been conducted to investigate this association, which have advanced our understanding of the events underpinning the observed risk. Narcolepsy with cataplexy (defined as type-1 narcolepsy, NT1) is characterized by an irreversible and chronic deficiency of hypocretin peptides in the hypothalamus. The multifactorial etiology is thought to include genetic predisposition, head trauma, environmental triggers, and/or infections (including influenza virus infections), and an increased risk was observed following administration of the A/California/7/2009 H1N1 vaccine Pandemrix (GSK). An autoimmune origin of NT1 is broadly assumed. This is based on its strong association with a predisposing allele (the human leucocyte antigen DQB1*0602) carried by the large majority of NT1 patients, and on links with other immune-related genetic markers affecting the risk of NT1. Presently, hypotheses on the underlying potential immunological mechanisms center on molecular mimicry between hypocretin and peptides within the A/California/7/2009 H1N1 virus antigen. This molecular mimicry may instigate a cross-reactive autoimmune response targeting hypocretin-producing neurons. Local CD4⁺ T-cell responses recognizing peptides from hypocretin are thought to play a central role in the response. In this model, cross-reactive DQB1*0602-restricted T cells from the periphery would be activated to cross the blood-brain barrier by rare, and possibly pathogen-instigated, inflammatory processes in the brain. Current hypotheses suggest that activation and expansion of cross-reactive T-cells by H1N1/09 influenza infection could have been amplified following the administration of the adjuvanted vaccine, giving rise to a “two-hit” hypothesis. The collective in silico, in vitro, and preclinical in vivo data from recent and ongoing research have progressively refined the hypothetical model of sequential immunological events, and filled multiple knowledge gaps. Though no definitive conclusions can be drawn, the mechanistical model plausibly explains the increased risk of NT1 observed following the 2009-2010 H1N1 pandemic and subsequent vaccination campaign, as outlined in this review.

Finnish children who experienced narcolepsy after receiving the Pandemrix vaccine during the 2009-2010 H1N1 pandemic demonstrated high level of psychosocial problems

AIM

We assessed psychosocial burdens in children who developed narcolepsy after receiving the Pandemrix H1N1 vaccine during the 2009-2010 pandemic. Parental quality of life was also assessed.

METHODS

This multicentre study covered four of the five Finnish University Hospital Districts, which dealt with about 90% of the paediatric narcolepsy cases after the Pandemrix vaccination. The medical records of children diagnosed from 2010 to 2014 were reviewed. The questionnaires included the Youth Self-Report (YSR), Children's Depression Inventory (CDI), the Child Behaviour Checklist (CBCL) and questions on parental resources, stress and quality of life.

RESULTS

We obtained the medical records of 94 children who were aged 5-17 years at the time of their narcolepsy diagnosis and questionnaire data for 73 of those children. Most children had strong narcolepsy symptoms, and 25% had CDI scores that suggested depression. In addition, 41% had total CBCL problem scores above the clinically significant limit and 48% were anxious, withdrawn and had somatic complaints. Sleep latency was weakly associated with the CBCL total problem score. Half of the children needed psychiatric interventions and parental stress was common.

CONCLUSION

Depression and behavioural problems were common in children with narcolepsy after the Pandemrix vaccination and their parents frequently reported feeling stressed.

Hepsin regulates TGFβ signaling via fibronectin proteolysis

Transforming growth factor‐beta (TGFβ) is a multifunctional cytokine with a well‐established role in mammary gland development and both oncogenic and tumor‐suppressive functions. The extracellular matrix (ECM) indirectly regulates TGFβ activity by acting as a storage compartment of latent‐TGFβ, but how TGFβ is released from the ECM via proteolytic mechanisms remains largely unknown. In this study, we demonstrate that hepsin, a type II transmembrane protease overexpressed in 70% of breast tumors, promotes canonical TGFβ signaling through the release of latent‐TGFβ from the ECM storage compartment. Mammary glands in hepsin CRISPR knockout mice showed reduced TGFβ signaling and increased epithelial branching, accompanied by increased levels of fibronectin and latent‐TGFβ1, while overexpression of hepsin in mammary tumors increased TGFβ signaling. Cell‐free and cell‐based experiments showed that hepsin is capable of direct proteolytic cleavage of fibronectin but not latent‐TGFβ and, importantly, that the ability of hepsin to activate TGFβ signaling is dependent on fibronectin. Altogether, this study demonstrates a role for hepsin as a regulator of the TGFβ pathway in the mammary gland via a novel mechanism involving proteolytic downmodulation of fibronectin.

Safety of Influenza A H1N1pdm09 Vaccines: An Overview of Systematic Reviews

Background

In 2009, a new influenza A H1N1 virus emerged causing a global pandemic. A range of monovalent influenza A H1N1pdm09 vaccines with or without adjuvants were developed. After the mass vaccination campaigns safety concerns related to H1N1pdm09 vaccines were reported. More than a decade later, reported AEFIs are still under scrutiny. We performed a systematic review aiming to synthesize the evidence on the safety of the H1N1pdm09 vaccines on reported outcomes from existing systematic reviews.

Methods

Four electronic databases, PubMed, EMBASE, Epistimonikos and the Cochrane Database of Systematic Reviews were searched for articles on H1N1pdm09 vaccination published from 2009 to January 2021. Systematic reviews assessing short- or long-term adverse events after H1N1pdm09 vaccination were considered for inclusion. Data was extracted from all selected reviews. Outcomes were grouped and results from each included review were presented narratively and in tables.

Results

16 systematic reviews met the inclusion criteria. Reported outcomes were short-term events (3 reviews), fetal/pregnancy outcomes (8 reviews), Guillain-Barré syndrome (GBS) (4 reviews), narcolepsy (2 reviews) demyelinating diseases (1 review based on one study only) and inflammatory bowel disease (IBD) (1 review). Short-term serious adverse events were rare, 3 cases amongst 16725 subjects in 18 randomized controlled trials (0.018%). No deaths were reported. The risks of local events were generally higher for adjuvanted vaccines as compared to unadjuvanted vaccines. Maternal H1N1pdm09 vaccination in any trimester was not associated with an increase in preterm birth, small for gestational age, congenital malformations or fetal death. For GBS, results were conflicting. The main systematic review on narcolepsy found a 5-14-fold increased risk in children, and a 2-7- fold increased risk in adults after vaccination with Pandemrix. The attributable risk of narcolepsy one year after vaccination was 1 case per 18 400 vaccine doses in children/adolescents, and 1 case per 181 000 vaccine doses in adults.

Conclusion

Adjuvanted vaccines had more local but not serious adverse events compared to unadjuvanted vaccines. Vaccination with Pandemrix was strongly associated with narcolepsy, particularly in children. No increased risks of pregnancy outcomes were seen after pandemic vaccination. The findings on GBS were inconclusive.

Update on Influenza Vaccines: Needs and Progress

Influenza is an annual seasonal epidemic, and occasionally pandemic, respiratory disease that causes considerable morbidity and mortality worldwide. Despite the widespread availability of safe and effective vaccines since the 1950s, this virus continues to pose a significant public health threat. Variable and often weak vaccine effectiveness, antigenic drift and shift, and vaccine hesitancy are some of the obstacles that must be overcome to control this disease. In this article, we briefly review current influenza vaccines, address safety concerns and the need for newer influenza vaccines of higher efficacy, and discuss efforts to create broadly protective, universal influenza vaccines.

Role of Placental Glucose Transporters in Determining Fetal Growth

Maternal nutrient availability and its transport through the placenta are crucial for fetal development. Nutrients are transported to the fetus via specific transporters present on the microvillous (MVM) and basal membrane (BM) of the placenta. Glucose is the most abundant nutrient transferred to the fetus and plays a key role in the fetal growth and development. The transfer of glucose across the human placenta is directly proportional to maternal glucose concentrations, and is mediated by glucose transporter family proteins (GLUTs). Maternal glucose concentration influences expression and activity of GLUTs in the MVM (glucose uptake) and BM (glucose delivery). Alteration in the number and function of these transporters may affect the growth and body composition of the fetus. The thin-fat phenotype of the Indian baby (low ponderal index, high adiposity) is proposed as a harbinger of future metabolic risk. We propose that placental function mediated through nutrient transporters contributes to the phenotype of the baby, specifically that glucose transporters will influence neonatal fat. This review discusses the role of various glucose transporters in the placenta in determining fetal growth and body composition, in light of the above hypothesis.

Enhanced influenza A H1N1 T cell epitope recognition and cross-reactivity to protein-O-mannosyltransferase 1 in Pandemrix-associated narcolepsy type 1

Narcolepsy type 1 (NT1) is a chronic neurological disorder having a strong association with HLA-DQB1*0602, thereby suggesting an immunological origin. Increased risk of NT1 has been reported among children or adolescents vaccinated with AS03 adjuvant-supplemented pandemic H1N1 influenza A vaccine, Pandemrix. Here we show that pediatric Pandemrix-associated NT1 patients have enhanced T-cell immunity against the viral epitopes, neuraminidase 175-189 (NA175-189) and nucleoprotein 214-228 (NP214-228), but also respond to a NA175-189-mimic, brain self-epitope, protein-O-mannosyltransferase 1 (POMT1675-689). A pathogenic role of influenza virus-specific T-cells and T-cell cross-reactivity in NT1 are supported by the up-regulation of IFN-γ, perforin 1 and granzyme B, and by the converging selection of T-cell receptor TRAV10/TRAJ17 and TRAV10/TRAJ24 clonotypes, in response to stimulation either with peptide NA175-189 or POMT1675-689. Moreover, anti-POMT1 serum autoantibodies are increased in Pandemrix-vaccinated children or adolescents. These results thus identify POMT1 as a potential autoantigen recognized by T- and B-cells in NT1.

A/H1N1 hemagglutinin antibodies show comparable affinity in vaccine-related Narcolepsy type 1 and control and are unlikely to contribute to pathogenesis

An increased incidence of narcolepsy type 1 (NT1) was observed in Scandinavia following the 2009-2010 influenza Pandemrix vaccination. The association between NT1 and HLA-DQB1*06:02:01 supported the view of the vaccine as an etiological agent. A/H1N1 hemagglutinin (HA) is the main antigenic determinant of the host neutralization antibody response. Using two different immunoassays, the Luciferase Immunoprecipitation System (LIPS) and Radiobinding Assay (RBA), we investigated HA antibody levels and affinity in an exploratory and in a confirmatory cohort of Swedish NT1 patients and healthy controls vaccinated with Pandemrix. HA antibodies were increased in NT1 patients compared to controls in the exploratory (LIPS p = 0.0295, RBA p = 0.0369) but not in the confirmatory cohort (LIPS p = 0.55, RBA p = 0.625). HA antibody affinity, assessed by competition with Pandemrix vaccine, was comparable between patients and controls (LIPS: 48 vs. 39 ng/ml, p = 0.81; RBA: 472 vs. 491 ng/ml, p = 0.65). The LIPS assay also detected higher HA antibody titres as associated with HLA-DQB1*06:02:01 (p = 0.02). Our study shows that following Pandemrix vaccination, HA antibodies levels and affinity were comparable NT1 patients and controls and suggests that HA antibodies are unlikely to play a role in NT1 pathogenesis.

Narcolepsy Type I as an autoimmune disorder

Narcolepsy Type 1 (NT1) is hypothesized to be an autoimmune disease targeting the hypocretin/orexin neurons in the lateral hypothalamus. Ample genetic and epidemiologic evidence point in the direction of a pathogenesis involving the immune system. Many autoantibodies have been detected in blood samples from NT1 patients, but none in a consistent manner. Importantly, T cells directed toward hypocretin/orexin neurons have been detected in samples from NT1 patients. However, it remains to be seen if these potentially autoreactive T cells are also present in the hypothalamus and if they are pathogenic. For this reason, NT1 does still not fully meet the criteria for being classified as a genuine autoimmune disease, even though more and more results are pointing in that direction as will be described in this chapter. The autoimmune hypothesis has led to many attempts at slowing or stopping disease progression with immunomodulatory treatment, but so far the overall results have not been very encouraging. It is clear that more research into the pathogenesis of NT1 is needed to establish the precise role of the immune system in disease development.

Vaccines for COVID-19

Since the emergence of COVID-19, caused by the SARS-CoV-2 virus at the end of 2019, there has been an explosion of vaccine development. By 24 September 2020, a staggering number of vaccines (more than 200) had started preclinical development, of which 43 had entered clinical trials, including some approaches that have not previously been licensed for human vaccines. Vaccines have been widely considered as part of the exit strategy to enable the return to previous patterns of working, schooling and socializing. Importantly, to effectively control the COVID-19 pandemic, production needs to be scaled-up from a small number of preclinical doses to enough filled vials to immunize the world's population, which requires close engagement with manufacturers and regulators. It will require a global effort to control the virus, necessitating equitable access for all countries to effective vaccines. This review explores the immune responses required to protect against SARS-CoV-2 and the potential for vaccine-induced immunopathology. We describe the profile of the different platforms and the advantages and disadvantages of each approach. The review also addresses the critical steps between promising preclinical leads and manufacturing at scale. The issues faced during this pandemic and the platforms being developed to address it will be invaluable for future outbreak control. Nine months after the outbreak began we are at a point where preclinical and early clinical data are being generated for the vaccines; an overview of this important area will help our understanding of the next phases.

Mass Spectrometric Characterization of Narcolepsy-Associated Pandemic 2009 Influenza Vaccines

The onset of narcolepsy, an irreversible sleep disorder, has been associated with 2009 influenza pandemic (pH1N1) infections in China, and with ASO3-adjuvanted pH1N1 vaccinations using Pandemrix in Europe. Intriguingly, however, the increased incidence was only observed following vaccination with Pandemrix but not Arepanrix in Canada. In this study, the mutational burden of actual vaccine lots of Pandemrix (n = 6) and Arepanrix (n = 5) sourced from Canada, and Northern Europe were characterized by mass spectrometry. The four most abundant influenza proteins across both vaccines were nucleoprotein NP, hemagglutinin HA, matrix protein M1, with the exception that Pandemrix harbored a significantly increased proportion of neuraminidase NA (7.5%) as compared to Arepanrix (2.6%). Most significantly, 17 motifs in HA, NP, and M1 harbored mutations, which significantly differed in Pandemrix versus Arepanrix. Among these, a 6-fold higher deamidation of HA146 (p.Asn146Asp) in Arepanrix was found relative to Pandemrix, while NP257 (p.Thr257Ala) and NP424 (p.Thr424Ile) were increased in Pandemrix. DQ0602 binding and tetramer analysis with mutated epitopes were conducted in Pandemrix-vaccinated cases versus controls but were unremarkable. Pandemrix harbored lower mutational burden than Arepanrix, indicating higher similarity to wild-type 2009 pH1N1, which could explain differences in narcolepsy susceptibility amongst the vaccines.

Mimicking myofibrillar protein denaturation in frozen-thawed meat: Effect of pH at high ionic strength

This study aims at providing new insight on protein denaturation in freezing-thawing. Freezing-thawing minced pork reduced water-holding of myofibrils and increased surface hydrophobicity. One additional freezing-thawing cycle at slow freezing rate caused appearance of a 160 kDa myosin-4 fragment in SDS-PAGE, further decreased water-holding of myofibrils and increased surface hydrophobicity. Fresh minced pork was exposed to either high salt (2 M KCl) only or high salt with lower pH to mimic conditions in freezing. Exposure to high salt only increased water-holding of myofibrils and hence did not reproduce myofibrillar protein changes in freezing. Exposure to combinations of lower pHs and high salt decreased water-holding and increased surface hydrophobicity, suggesting myofibrillar protein denaturation occurred by a comparable mechanism as in freezing-thawing. We propose that exposure to decreased pH combined with high solute concentrations in the unfrozen water of frozen meat is the primary cause of myofibrillar protein denaturation in frozen-thawed meat.

Sourdough Fermentation Degrades Wheat Alpha-Amylase/Trypsin Inhibitor (ATI) and Reduces Pro-Inflammatory Activity

The ingestion of gluten-containing foods can cause wheat-related disorders in up to 15% of wheat consuming populations. Besides the role of gluten, α-amylase/trypsin inhibitors (ATI) have recently been identified as inducers of an innate immune response via toll-like receptor 4 in celiac disease and non-celiac wheat sensitivity. ATI are involved in plant self-defense against insects and possibly in grain development. Notably, they are largely resistant to gastrointestinal proteases and heat, and their inflammatory activity affects not only the intestine, but also peripheral organs. The aim of this study was to understand the changes of ATI throughout the sourdough and yeast-fermented bread-making processes. ATI tetramers were isolated, fluorescein-labelled, and added to a mini-dough bread-making system. When the pH decreased below 4.0 in sourdough fermentation, the ATI tetramers were degraded due to the activation of aspartic proteases, whilst in yeast fermentation, ATI tetramers remained intact. The amylase inhibitory activity after sourdough fermentation decreased significantly, while the concentration of free thiol groups increased. The glutathione reductase activity of Fructilactobacillus sanfranciscensis did not contribute to the reduction of ATI tetramers. Compared to the unfermented wheat, sourdough fermentation was able to decrease the release of pro-inflammatory cytokines monocyte chemoattractant protein-1 (MCP-1) and tumor necrosis factor alpha (TNF-α) in quantitative ATI extracts added to the human monocytic cell line THP-1. The current data suggest that sourdough fermentation can degrade ATI structure and bioactivity, and point to strategies to improve product development for wheat sensitivity patients.

The 2009 H1N1 pandemic, vaccine-associated narcolepsy, and the politics of risk and harm

The article traces the emergence of a new type of vaccine injury—vaccine-associated narcolepsy—following immunization with Pandemrix vaccine during the 2009 H1N1 pandemic in Europe. The article highlights the processual nature of vaccine injury: it shows how vaccine-associated narcolepsy emerges gradually as a recognized object through epidemiological and immunological studies as well as patient organizations’ public discourses. The article argues that despite public recognition of injury, vaccine-associated narcolepsy remains an incongruous object characterized by underlying tensions. These tensions take shape in relation to the history of vaccine injury debates, on the one hand, and the connection between vaccine-associated narcolepsy and non-vaccine-related narcolepsy, on the other. The article shows how these underlying tensions enable a range of mutually incompatible framings and mobilizations through which risk, harm, responsibility, and justice are claimed and negotiated.

No evidence of autoimmunity to human OX1 or OX2 orexin receptors in Pandemrix-vaccinated narcoleptic children

Narcolepsy type 1, likely an immune-mediated disease, is characterized by excessive daytime sleepiness and cataplexy. The disease is strongly associated with human leukocyte antigen (HLA) DQB1∗06:02. A significant increase in the incidence of childhood and adolescent narcolepsy was observed after a vaccination campaign with AS03-adjuvanted Pandemrix influenza vaccine in Nordic and several other countries in 2010 and 2011. Previously, it has been suggested that a surface-exposed region of influenza A nucleoprotein, a structural component of the Pandemrix vaccine, shares amino acid residues with the first extracellular domain of the human OX₂ orexin/hypocretin receptor eliciting the development of autoantibodies. Here, we analyzed, whether H1N1pdm09 infection or Pandemrix vaccination contributed to the development of autoantibodies to the orexin precursor protein or the OX₁ or OX₂ receptors. The analysis was based on the presence or absence of autoantibody responses against analyzed proteins. Entire OX₁ and OX₂ receptors or just their extracellular N-termini were transiently expressed in HuH7 cells to determine specific antibody responses in human sera. Based on our immunofluorescence analysis, none of the 56 Pandemrix-vaccinated narcoleptic patients, 28 patients who suffered from a laboratory-confirmed H1N1pdm09 infection or 19 Pandemrix-vaccinated controls showed specific autoantibody responses to prepro-orexin, orexin receptors or the isolated extracellular N-termini of orexin receptors. We also did not find any evidence for cell-mediated immunity against the N-terminal epitopes of OX₂. Our findings do not support the hypothesis that the surface-exposed region of the influenza nucleoprotein A would elicit the development of an immune response against orexin receptors.

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No evidence of humoral immunity against human OX₁ or OX₂ orexin receptors.

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No cross-reactive antibodies between influenza virus NP and orexin receptors.

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No evidence for cell-mediated immunity against the N-terminal epitopes of OX₂.

Cytokines in narcolepsy: A systematic review and meta-analysis

BACKGROUND

Narcolepsy is a sleep disorder characterized by a loss of hypocretin neurons in the hypothalamus. Inflammation is proposed as a mechanism for neurodegeneration in narcolepsy. Numerous studies have investigated peripheral cytokine measures in narcoleptic patients, though the results are not conclusive. The current systematic review and meta-analysis aims to address the question of how do serum/plasma cytokine levels change in narcolepsy.

METHODS

A systematic search of the literature to July 2019, was conducted to identify studies that measured cytokine levels in patients with narcolepsy, compared with those in controls without narcolepsy.

RESULTS

Twelve studies were included in the meta-analysis: ten for interleukin (IL)-6, five for IL-8, three for IL-10, and ten for tumor necrosis factor alpha (TNF-α). Compared with controls, patients with narcolepsy had higher plasma levels of IL-6 (95% CI [0.22, 3.74]; P = 0.03) and TNF-α (95% CI [0.53, 4.18]; P = 0.01), while did not significantly differ in plasma IL-8 (95% CI [-1.64, 2.08]; P = 0.82) and IL-10 (95% CI [-1.29, 0.72]; P = 0.57) as well as serum IL-6 (95% CI [-1.48, 0.32], P = 0.21) and TNF-α (95% CI [-3.14, 0.19], P = 0.08) and CSF IL-8 (95% CI [-1.16, 0.41]; P = 0.35) levels. Patients with narcolepsy exhibited lower CSF IL-6 (95% CI [-0.66, 0.06]; P = 0.02) levels comparing with controls.

CONCLUSIONS

Patients with narcolepsy had elevated plasma levels of IL-6 and TNF-α and lower levels of CSF IL-6 than non-narcoleptic controls. Our results support the role of inflammation in the pathophysiology of narcolepsy. However, plasma levels of IL-8 and IL-10, serum levels of IL-6 and TNF-α and CSF IL-8 did not significantly differ between patients and controls.

Physiology of gangliosides and the role of antiganglioside antibodies in human diseases

Gangliosides are structurally and functionally polymorphic sialic acid containing glycosphingolipids that are widely distributed in the human body. They play important roles in protecting us against immune attacks, yet they can become targets for autoimmunity and act as receptors for microbes, like the influenza viruses, and toxins, such as the cholera toxin. The expression patterns of gangliosides vary in different tissues, during different life periods, as well as in different animals. Antibodies against gangliosides (AGA) can target immune attack e.g., against neuronal cells and neutralize their complement inhibitory activity. AGAs are important especially in acquired demyelinating immune-mediated neuropathies, like Guillain-Barré syndrome (GBS) and its variant, the Miller-Fisher syndrome (MFS). They can emerge in response to different microbial agents and immunological insults. Thereby, they can be involved in a variety of diseases. In addition, antibodies against GM3 were found in the sera of patients vaccinated with Pandemrix®, who developed secondary narcolepsy, strongly supporting the autoimmune etiology of the disease.

Narcolepsy type 1: what have we learned from immunology?

Narcolepsy type 1 is hypothesized to be an autoimmune disease targeting the hypocretin/orexin neurons in the hypothalamus. Ample genetic and epidemiological evidence points in the direction of a pathogenesis involving the immune system, but this is not considered proof of autoimmunity. In fact, it remains a matter of debate how to prove that a given disease is indeed an autoimmune disease. In this review, a set of commonly used criteria for autoimmunity is described and applied to narcolepsy type 1. In favor of the autoimmune hypothesis are data showing that in narcolepsy type 1 a specific adaptive immune response is directed to hypocretin/orexin neurons. Autoreactive T cells and autoantibodies have been detected in blood samples from patients, but it remains to be seen if these T cells or antibodies are in fact present in the hypothalamus. It is also unclear if the autoreactive T cells and/or autoantibodies can transfer the disease to healthy individuals or animals or if immunization with the proposed autoantigens can induce the disease in animal models. Most importantly, it is still controversial whether suppression of the autoimmune response can prevent disease progression. In conclusion, narcolepsy type 1 does still not fully meet the criteria for being classified as a genuine autoimmune disease, but more and more results are pointing in that direction.

Oil-in-water emulsion adjuvants for pediatric influenza vaccines: a systematic review and meta-analysis

Standard inactivated influenza vaccines are poorly immunogenic in immunologically naive healthy young children, who are particularly vulnerable to complications from influenza. For them, there is an unmet need for better influenza vaccines. Oil-in-water emulsion-adjuvanted influenza vaccines are promising candidates, but clinical trials yielded inconsistent results. Here, we meta-analyze randomized controlled trials with efficacy data (3 trials, n = 15,310) and immunogenicity data (17 trials, n = 9062). Compared with non-adjuvanted counterparts, adjuvanted influenza vaccines provide a significantly better protection (weighted estimate for risk ratio of RT-PCR-confirmed influenza: 0.26) and are significantly more immunogenic (weighted estimates for seroprotection rate ratio: 4.6 to 7.9) in healthy immunologically naive young children. Nevertheless, in immunologically non-naive children, adjuvanted and non-adjuvanted vaccines provide similar protection and are similarly immunogenic. These results indicate that oil-in-water emulsion adjuvant improves the efficacy of inactivated influenza vaccines in healthy young children at the first-time seasonal influenza vaccination.

An indirect comparison meta-analysis of AS03 and MF59 adjuvants in pandemic influenza A(H1N1)pdm09 vaccines

BACKGROUND

Although oil-in-water adjuvants improve pandemic influenza vaccine efficacy, AS03 versus MF59 adjuvant comparisons in A(H1N1)pdm09 pandemic vaccines are lacking.

METHODS

We conducted an indirect-comparison meta-analysis extracting published data from randomised controlled trials in literature databases (01/01/2009-09/09/2018), evaluating immunogenicity and safety of AS03- or MF59-adjuvanted vaccines. We conducted comparisons of log-transformed haemagglutination inhibition geometric mean titre ratio (GMTR; primary outcome) of different regimens of each adjuvant versus unadjuvanted counterparts. Then via test of subgroup differences, we indirectly compared different AS03 versus MF59 regimens.

RESULTS

We identified 22 publications with 10,734 participants. In adults, AS03-adjuvanted vaccines (3.75 µg haemagglutinin) achieved superior GMTR versus unadjuvanted vaccines (all four comparisons); MD = 0.56 (95%CI 0.33 to 0.80, p < 0.001) to 1.18 (95%CI 0.72 to 1.65, p < 0.001). MF59 (full-dose)-adjuvanted vaccines (7.5 µg haemagglutinin) were superior to unadjuvanted vaccines (three of four comparisons); MD = 0.47 (95%CI 0.19 to 0.75, p = 0.001) to 0.80 (95%CI 0.44 to 1.16, p < 0.001). Adult indirect comparisons favoured AS03 over MF59 (six of eight comparisons; p < 0.001 to p = 0.088). Paediatric indirect comparisons favoured MF59-adjuvanted vaccines (two of seven comparisons; p = 0.011, 0.079). However, unadjuvanted control group seroconversion rate was lower in MF59 than AS03 studies (p < 0.001 to p = 0.097). There was substantial heterogeneity, and adult AS03 studies had lower risk of bias.

CONCLUSIONS

Despite limited studies, in adults, AS03-adjuvanted vaccines allow antigen sparing versus MF59-adjuvanted and unadjuvanted vaccines, with similar immunogenicity, but higher risk of pain and fatigue (secondary outcomes) than unadjuvanted vaccines. In children, adjuvanted vaccines are also superior, but the better adjuvant is uncertain.

Burden, effectiveness and safety of influenza vaccines in elderly, paediatric and pregnant populations

Vaccination is the most practical means available for preventing influenza. Influenza vaccines require frequent updates to keep pace with antigenic drift of the virus, and the effectiveness, and sometimes the safety, of the vaccine can therefore vary from season to season. Three key populations that the World Health Organization recommends should be prioritized for influenza vaccination are pregnant women, children younger than 5 years of age and the elderly. This review discusses the burden of influenza and the safety and effectiveness profile of influenza vaccines recommended for these groups.

The neurobiological basis of narcolepsy

Narcolepsy is the most common neurological cause of chronic sleepiness. The discovery about 20 years ago that narcolepsy is caused by selective loss of the neurons producing orexins (also known as hypocretins) sparked great advances in the field. Here, we review the current understanding of how orexin neurons regulate sleep-wake behaviour and the consequences of the loss of orexin neurons. We also summarize the developing evidence that narcolepsy is an autoimmune disorder that may be caused by a T cell-mediated attack on the orexin neurons and explain how these new perspectives can inform better therapeutic approaches.

Autoimmunity to hypocretin and molecular mimicry to flu in type 1 narcolepsy

This work shows that the amidated terminal ends of the secreted hypocretin (HCRT) peptides (HCRT_NH2) are autoantigens in type 1 narcolepsy, an autoimmune disorder targeting HCRT neurons. The autoimmune process is usually initiated by influenza A flu infections, and a particular piece of the hemagglutinin (HA) flu protein of the pandemic 2009 H1N1 strain was identified as a likely trigger. This HA epitope has homology with HCRT_NH2 and T cells cross-reactive to both epitopes are involved in the autoimmune process by molecular mimicry. Genes associated with narcolepsy mark the particular HLA heterodimer (DQ0602) involved in presentation of these antigens and modulate expression of the specific T cell receptor segments (TRAJ24 and TRBV4-2) involved in T cell receptor recognition of these antigens, suggesting causality.

Type 1 narcolepsy (T1N) is caused by hypocretin/orexin (HCRT) neuronal loss. Association with the HLA DQB1*06:02/DQA1*01:02 (98% vs. 25%) heterodimer (DQ0602), T cell receptors (TCR) and other immune loci suggest autoimmunity but autoantigens are unknown. Onset is seasonal and associated with influenza A, notably pandemic 2009 H1N1 (pH1N1) infection and vaccination (Pandemrix). Peptides derived from HCRT and influenza A, including pH1N1, were screened for DQ0602 binding and presence of cognate DQ0602 tetramer-peptide–specific CD4⁺ T cells tested in 35 T1N cases and 22 DQ0602 controls. Higher reactivity to influenza pHA_273–287 (pH1N1 specific), PR8 (H1N1 pre-2009 and H2N2)-specific NP_17–31 and C-amidated but not native version of HCRT_54–66 and HCRT_86–97 (HCRT_NH2) were observed in T1N. Single-cell TCR sequencing revealed sharing of CDR3β TRBV4-2-CASSQETQGRNYGYTF in HCRT_NH2 and pHA_273–287-tetramers, suggesting molecular mimicry. This public CDR3β uses TRBV4-2, a segment modulated by T1N-associated SNP rs1008599, suggesting causality. TCR-α/β CDR3 motifs of HCRT_54–66-NH2 and HCRT_86–97-NH2 tetramers were extensively shared: notably public CDR3α, TRAV2-CAVETDSWGKLQF-TRAJ24, that uses TRAJ24, a chain modulated by T1N-associated SNPs rs1154155 and rs1483979. TCR-α/β CDR3 sequences found in pHA_273–287, NP_17–31, and HCRT_NH2 tetramer-positive CD4⁺ cells were also retrieved in single INF-γ–secreting CD4⁺ sorted cells stimulated with Pandemrix, independently confirming these results. Our results provide evidence for autoimmunity and molecular mimicry with flu antigens modulated by genetic components in the pathophysiology of T1N.

Incidence rates of narcolepsy diagnoses in Taiwan, Canada, and Europe: The use of statistical simulation to evaluate methods for the rapid assessment of potential safety issues on a population level in the SOMNIA study

Background & objectives

Vaccine safety signals require investigation, which may be done rapidly at the population level using ecological studies, before embarking on hypothesis-testing studies. Incidence rates were used to assess a signal of narcolepsy following AS03-adjuvanted monovalent pandemic H1N1 (pH1N1) influenza vaccination among children and adolescents in Sweden and Finland in 2010. We explored the utility of ecological data to assess incidence of narcolepsy following exposure to pandemic H1N1 virus or vaccination in 10 sites that used different vaccines, adjuvants, and had varying vaccine coverage.

Methods

We calculated incidence rates of diagnosed narcolepsy for periods defined by influenza virus circulation and vaccination campaign dates, and used Poisson regression to estimate incidence rate ratios (IRRs) comparing the periods during which wild-type virus circulated and after the start of vaccination campaigns vs. the period prior to pH1N1 virus circulation. We used electronic health care data from Sweden, Denmark, the United Kingdom, Canada (3 provinces), Taiwan, Netherlands, and Spain (2 regions) from 2003 to 2013. We investigated interactions between age group and adjuvant in European sites and conducted a simulation study to investigate how vaccine coverage, age, and the interval from onset to diagnosis may impact the ability to detect safety signals.

Results

Incidence rates of narcolepsy varied by age, continent, and period. Only in Taiwan and Sweden were significant time-period-by-age-group interactions observed. Associations were found for children in Taiwan (following pH1N1 virus circulation) and Sweden (following vaccination). Simulations showed that the individual-level relative risk of narcolepsy was underestimated using ecological methods comparing post- vs. pre-vaccination periods; this effect was attenuated with higher vaccine coverage and a shorter interval from disease onset to diagnosis.

Conclusions

Ecological methods can be useful for vaccine safety assessment but the results are influenced by diagnostic delay and vaccine coverage. Because ecological methods assess risk at the population level, these methods should be treated as signal-generating methods and drawing conclusions regarding individual-level risk should be avoided.

Narcolepsy Associated with Pandemrix Vaccine

PURPOSE OF REVIEW

After the connection between AS03-adjuvanted pandemic H1N1 vaccine Pandemrix and narcolepsy was recognized in 2010, research on narcolepsy has been more intensive than ever before. The purpose of this review is to provide the reader with current concepts and recent findings on the Pandemrix-associated narcolepsy.

RECENT FINDINGS

After the Pandemrix vaccination campaign in 2009-2010, the risk of narcolepsy was increased 5- to 14-fold in children and adolescents and 2- to 7-fold in adults. According to observational studies, the risk of narcolepsy was elevated for 2 years after the Pandemrix vaccination. Some confounding factors and potential diagnostic biases may influence the observed narcolepsy risk in some studies, but it is unlikely that they would explain the clearly increased incidence in all the countries where Pandemrix was used. An increased risk of narcolepsy after natural H1N1 infection was reported from China, where pandemic influenza vaccination was not used. There is more and more evidence that narcolepsy is an autoimmune disease. All Pandemrix-associated narcolepsy cases have been positive for HLA class II DQB1*06:02 and novel predisposing genetic factors directly linking to the immune system have been identified. Even though recent studies have identified autoantibodies against multiple neuronal structures and other host proteins and peptides, no specific autoantigens that would explain the disease mechanism in narcolepsy have been identified thus far. There was a marked increase in the incidence of narcolepsy after Pandemrix vaccination, especially in adolescents, but also in young adults and younger children. All vaccine-related cases were of narcolepsy type 1 characterized by hypocretin deficiency in the central nervous system. The disease phenotype and the severity of symptoms varied considerably in children and adolescents suffering from Pandemrix-associated narcolepsy, but they were indistinguishable from the symptoms of idiopathic narcolepsy. Narcolepsy type 1 is most likely an autoimmune disease, but the mechanisms have remained elusive.

Prostaglandin D2 Receptor DP1 Antibodies Predict Vaccine-induced and Spontaneous Narcolepsy Type 1: Large-scale Study of Antibody Profiling

BACKGROUND

Neuropathological findings support an autoimmune etiology as an underlying factor for loss of orexin-producing neurons in spontaneous narcolepsy type 1 (narcolepsy with cataplexy; sNT1) as well as in Pandemrix influenza vaccine-induced narcolepsy type 1 (Pdmx-NT1). The precise molecular target or antigens for the immune response have, however, remained elusive.

METHODS

Here we have performed a comprehensive antigenic repertoire analysis of sera using the next-generation phage display method - mimotope variation analysis (MVA). Samples from 64 children and adolescents were analyzed: 10 with Pdmx-NT1, 6 with sNT1, 16 Pandemrix-vaccinated, 16 H1N1 infected, and 16 unvaccinated healthy individuals. The diagnosis of NT1 was defined by the American Academy of Sleep Medicine international criteria of sleep disorders v3.

FINDINGS

Our data showed that although the immunoprofiles toward vaccination were generally similar in study groups, there were also striking differences in immunoprofiles between sNT1 and Pdmx-NT1 groups as compared with controls. Prominent immune response was observed to a peptide epitope derived from prostaglandin D2 receptor (DP1), as well as peptides homologous to B cell lymphoma 6 protein. Further validation confirmed that these can act as true antigenic targets in discriminating NT1 diseased along with a novel epitope of hemagglutinin of H1N1 to delineate exposure to H1N1.

INTERPRETATION

We propose that DP1 is a novel molecular target of autoimmune response and presents a potential diagnostic biomarker for NT1. DP1 is involved in the regulation of non-rapid eye movement (NREM) sleep and thus alterations in its functions could contribute to the disturbed sleep regulation in NT1 that warrants further studies. Together our results also show that MVA is a helpful method for finding novel peptide antigens to classify human autoimmune diseases, possibly facilitating the design of better therapies.

Pandemrix® vaccination is not associated with increased risk of islet autoimmunity or type 1 diabetes in the TEDDY study children

AIMS/HYPOTHESIS

During the A/H1N1 2009 (A/California/04/2009) pandemic, mass vaccination with a squalene-containing vaccine, Pandemrix®, was performed in Sweden and Finland. The vaccination was found to cause narcolepsy in children and young adults with the HLA-DQ 6.2 haplotype. The aim of this study was to investigate if exposure to Pandemrix® similarly increased the risk of islet autoimmunity or type 1 diabetes.

METHODS

In The Environmental Determinants of Diabetes in the Young (TEDDY) study, children are followed prospectively for the development of islet autoimmunity and type 1 diabetes. In October 2009, when the mass vaccination began, 3401 children at risk for islet autoimmunity and type 1 diabetes were followed in Sweden and Finland. Vaccinations were recorded and autoantibodies against insulin, GAD65 and insulinoma-associated protein 2 were ascertained quarterly before the age of 4 years and semi-annually thereafter.

RESULTS

By 5 August 2010, 2413 of the 3401 (71%) children observed as at risk for an islet autoantibody or type 1 diabetes on 1 October 2009 had been vaccinated with Pandemrix®. By 31 July 2016, 232 children had at least one islet autoantibody before 10 years of age, 148 had multiple islet autoantibodies and 96 had developed type 1 diabetes. The risk of islet autoimmunity was not increased among vaccinated children. The HR (95% CI) for the appearance of at least one islet autoantibody was 0.75 (0.55, 1.03), at least two autoantibodies was 0.85 (0.57, 1.26) and type 1 diabetes was 0.67 (0.42, 1.07). In Finland, but not in Sweden, vaccinated children had a lower risk of islet autoimmunity (0.47 [0.29, 0.75]), multiple autoantibodies (0.50 [0.28, 0.90]) and type 1 diabetes (0.38 [0.20, 0.72]) compared with those who did not receive Pandemrix®. The analyses were adjusted for confounding factors.

CONCLUSIONS/INTERPRETATION

Children with an increased genetic risk for type 1 diabetes who received the Pandemrix® vaccine during the A/H1N1 2009 pandemic had no increased risk of islet autoimmunity, multiple islet autoantibodies or type 1 diabetes. In Finland, the vaccine was associated with a reduced risk of islet autoimmunity and type 1 diabetes.

AS03- and MF59-Adjuvanted Influenza Vaccines in Children

Influenza is a major cause of respiratory disease leading to hospitalization in young children. However, seasonal trivalent influenza vaccines (TIVs) have been shown to be ineffective and poorly immunogenic in this population. The development of live-attenuated influenza vaccines and adjuvanted vaccines are important advances in the prevention of influenza in young children. The oil-in-water emulsions MF59 and adjuvant systems 03 (AS03) have been used as adjuvants in both seasonal adjuvanted trivalent influenza vaccines (ATIVs) and pandemic monovalent influenza vaccines. Compared with non-adjuvanted vaccine responses, these vaccines induce a more robust and persistent antibody response for both homologous and heterologous influenza strains in infants and young children. Evidence of a significant improvement in vaccine efficacy with these adjuvanted vaccines resulted in the use of the monovalent (A/H1N1) AS03-adjuvanted vaccine in children in the 2009 influenza pandemic and the licensure of the seasonal MF59 ATIV for children aged 6 months to 2 years in Canada. The mechanism of action of MF59 and AS03 remains unclear. Adjuvants such as MF59 induce proinflammatory cytokines and chemokines, including CXCL10, but independently of type-1 interferon. This proinflammatory response is associated with improved recruitment, activation and maturation of antigen presenting cells at the injection site. In young children MF59 ATIV produced more homogenous and robust transcriptional responses, more similar to adult-like patterns, than did TIV. Early gene signatures characteristic of the innate immune response, which correlated with antibody titers were also identified. Differences were detected when comparing child and adult responses including opposite trends in gene set enrichment at day 3 postvaccination and, unlike adult data, a lack of correlation between magnitude of plasmablast response at day 7 and antibody titers at day 28 in children. These insights show the utility of novel approaches in understanding new adjuvants and their importance for developing improved influenza vaccines for children.

Absence of anti-hypocretin receptor 2 autoantibodies in post pandemrix narcolepsy cases

Background

A recent publication suggested molecular mimicry of a nucleoprotein (NP) sequence from A/Puerto Rico/8/1934 (PR8) strain, the backbone used in the construction of the reassortant strain X-179A that was used in Pandemrix^® vaccine, and reported on anti-hypocretin (HCRT) receptor 2 (anti-HCRTR2) autoantibodies in narcolepsy, mostly in post Pandemrix^® narcolepsy cases (17 of 20 sera). In this study, we re-examined this hypothesis through mass spectrometry (MS) characterization of Pandemrix^®, and two other pandemic H1N1 (pH1N1)-2009 vaccines, Arepanrix^® and Focetria^®, and analyzed anti-HCRTR2 autoantibodies in narcolepsy patients and controls using three independent strategies.

Methods

MS characterization of Pandemrix^® (2 batches), Arepanrix^® (4 batches) and Focetria^® (1 batch) was conducted with mapping of NP 116I or 116M spectrogram. Two sets of narcolepsy cases and controls were used: 40 post Pandemrix^® narcolepsy (PP-N) cases and 18 age-matched post Pandemrix^® controls (PP-C), and 48 recent (≤6 months) early onset narcolepsy (EO-N) cases and 70 age-matched other controls (O-C). Anti-HCRTR2 autoantibodies were detected using three strategies: (1) Human embryonic kidney (HEK) 293T cells with transient expression of HCRTR2 were stained with human sera and then analyzed by flow cytometer; (2) In vitro translation of [³⁵S]-radiolabelled HCRTR2 was incubated with human sera and immune complexes of autoantibody and [³⁵S]-radiolabelled HCRTR2 were quantified using a radioligand-binding assay; (3) Optical density (OD) at 450 nm (OD450) of human serum immunoglobulin G (IgG) binding to HCRTR2 stably expressed in Chinese hamster ovary (CHO)-K1 cell line was measured using an in-cell enzyme-linked immunosorbent assay (ELISA).

Results

NP 116M mutations were predominantly present in all batches of Pandemrix^®, Arepanrix^® and Focetria^®. The wild-type NP_109-123 (ILYDKEEIRRIWRQA), a mimic to HCRTR2_34-45 (YDDEEFLRYLWR), was not found to bind to DQ0602. Three or four subjects were found positive for anti-HCRTR2 autoantibodies using two strategies or the third one, respectively. None of the post Pandemrix^® narcolepsy cases (0 of 40 sera) was found positive with all three strategies.

Conclusion

Anti-HCRTR2 autoantibody is not a significant biological feature of narcolepsy or of post Pandemrix^® autoimmune responses.

Autoimmunity in narcolepsy

PURPOSE OF REVIEW

Summarize the recent findings in narcolepsy focusing on the environmental and genetic risk factors in disease development.

RECENT FINDINGS

Both genetic and epidemiological evidence point towards an autoimmune mechanism in the destruction of orexin/hypocretin neurons. Recent studies suggest both humoral and cellular immune responses in the disease development.

SUMMARY

Narcolepsy is a severe sleep disorder, in which neurons producing orexin/hypocretin in the hypothalamus are destroyed. The core symptoms of narcolepsy are debilitating, extreme sleepiness, cataplexy, and abnormalities in the structure of sleep. Both genetic and epidemiological evidence point towards an autoimmune mechanism in the destruction of orexin/hypocretin neurons. Importantly, the highest environmental risk is seen with influenza-A infection and immunization. However, how the cells are destroyed is currently unknown. In this review we summarize the disease symptoms, and focus on the immunological findings in narcolepsy. We also discuss the environmental and genetic risk factors as well as propose a model for disease development.

Narcolepsy Type 1 as an Autoimmune Disorder: Evidence, and Implications for Pharmacological Treatment

Narcolepsy type 1 (NT1) is a rare sleep disorder caused by the very specific loss of hypothalamic hypocretin (Hcrt)/orexin neurons. The exact underlying process leading to this destruction is yet unknown, but indirect evidence strongly supports an autoimmune origin. The association with immune-related genetic factors, in particular the strongest association ever reported in a disease with an allele of a human leukocyte antigen (HLA) gene, and with environmental factors (i.e., the H1N1 influenza infection and vaccination during the pandemic in 2009) are in favor of such a hypothesis. The loss of Hcrt neurons is irreversible, and NT1 is currently an incurable and disabling condition. Patients are managed with symptomatic medication, targeting the main symptoms (excessive daytime sleepiness, cataplexy, disturbed nocturnal sleep), and they require a lifelong treatment. Improved diagnostic tools, together with an increased understanding of the pathogenesis of NT1, may lead to new therapeutic and even preventive interventions. One future treatment could include Hcrt replacement, but this neuropeptide does not cross the blood-brain barrier. However, Hcrt receptor agonists may be promising candidates to treat NT1. Another option is immune-based therapies, administered at disease onset, with already some initiatives to slow down or stop the dysimmune process. Whether immune-based therapy could be beneficial in NT1 remains, however, to be proven.

Influenza vaccine use to protect healthy children: A debated topic

At the beginning of this century, a number of studies suggested that in healthy children, particularly those <2years of age, influenza could have a serious and complicated course, as it frequently led to hospitalization and sometimes, albeit rarely, to death. Moreover, pre-schoolers and school-age children were found to be among the most important causes of influenza transmission to the community, as they shed the virus for a longer time than adults and had frequent contact with greater numbers of individuals through day-care and school. These findings led a number of health authorities to modify the official recommendations regarding the use of influenza vaccine in healthy children. Several factors seem to indicate that vaccination against influenza in healthy children of any age and in pregnant women could be effective in preventing the disease in the entire paediatric population and in providing herd immunity in adults and old people as well. The direct advantages of the vaccine seem greater in younger subjects, particularly those <2-3years of age. Vaccination of older children is considered effective by most experts, but high vaccination coverage of these subjects has been difficult to attain. Similar difficulties have been identified for the vaccination of pregnant women. These challenges can be overcome, at least in part, by appropriate information and accurate evaluations of available data. In addition, further studies specifically designed to clarify unresolved problems regarding vaccine use in paediatric and pregnant populations are needed to convince reluctant health authorities. More effective vaccines for younger children as well as improved availability of data regarding the optimal time period for vaccine administration in pregnant women appear relevant in this regard.

Induction of cellular and molecular Immunomodulatory pathways by vitamin E and vitamin C

INTRODUCTION

Vitamins E and C are well known small molecules that have been used to maintain health for decades. Recent studies of the cellular and molecular pathways leading to immunomodulation by these molecules have been of interest, as have their anti-oxidant properties and signal transduction pathways for curing or improving infectious diseases and cancer. Areas covered: Herein, the authors provide a definition and the structural classification of vitamins E and C and how these molecules influence cellular function. The studies include in vitro, ex vivo and in vivo studies in animal models as well as clinical trials. The authors give particular focus to the scientifically factual and putative roles of these molecules in innate and adaptive immunomodulation and prevention or cure of diseases. Expert opinion: The antioxidant properties of vitamins E and C are well studied. However, whether there is a link between their antioxidant and immunomodulation properties is unclear. In addition, there is a strong, albeit putative, prevailing notion that vitamin C can prevent or cure infectious diseases or cancer. Presently, while there is proven evidence that vitamin E possesses immunomodulatory properties that may play a positive role in disease outcomes, this evidence is less available for vitamin C.

Antibody Affinity Against 2009 A/H1N1 Influenza and Pandemrix Vaccine Nucleoproteins Differs Between Childhood Narcolepsy Patients and Controls

Increased narcolepsy incidence was observed in Sweden following the 2009 influenza vaccination with Pandemrix^®. A substitution of the 2009 nucleoprotein for the 1934 variant has been implicated in narcolepsy development. The aims were to determine (a) antibody levels toward wild-type A/H1N1-2009[A/California/04/2009(H1N1)] (NP-CA2009) and Pandemrix-[A/Puerto Rico/8/1934(H1N1)] (NP-PR1934) nucleoproteins in 43 patients and 64 age-matched controls; (b) antibody affinity in reciprocal competitive assays in 11 childhood narcolepsy patients compared with 21 age-matched controls; and (c) antibody levels toward wild-type A/H1N1-2009[A/California/04/2009(H1N1)] (H1N1 NS1), not a component of the Pandemrix vaccine. In vitro transcribed and translated ³⁵S-methionine-labeled H1N1 influenza A virus proteins were used in radiobinding reciprocal competition assays to estimate antibody levels and affinity (Kd). Childhood patients had higher NP-CA2009 (p = 0.0339) and NP-PR1934 (p = 0.0246) antibody levels compared with age-matched controls. These childhood controls had lower NP-CA2009 (p = 0.0221) and NP-PR1934 (p = 0.00619) antibodies compared with controls 13 years or older. In contrast, in patients 13 years or older, the levels of NP-PR1934 (p = 0.279) and NP-CA2009 (p = 0.0644) antibodies did not differ from the older controls. Childhood antibody affinity (Kd) against NP-CA2009 was comparable between controls (68 ng/mL) and patients (74 ng/mL; p = 0.21) with NP-CA2009 and NP-PR1934 displacement (controls: 165 ng/mL; patients: 199 ng/mL; p = 0.48). In contrast, antibody affinity against NP-PR1934 was higher in controls with either NP-PR1934 (controls: 9 ng/mL; patients: 20 ng/mL; p = 0.0031) or NP-CA2009 (controls: 14 ng/mL; patients: 23 ng/mL; p = 0.0048). A/H1N1-NS1 antibodies were detected in 0/43 of the narcolepsy patients compared with 3/64 (4.7%) controls (p = 0.272). Similarly, none (0/11) of the childhood patients and 1/21 (4.8%) of the childhood controls had A/H1N1-NS1 antibodies. The higher antibody affinities against NP-PR1934 in controls suggest better protection against wild-type virus. In contrast, the reduced NP-PR1934 antibody affinities among childhood narcolepsy patients suggest poor protection from the wild-type A/H1N1 virus and possibly increased risk for viral damage.

Incidence of narcolepsy after H1N1 influenza and vaccinations: Systematic review and meta-analysis

An increased incidence of narcolepsy was seen in many countries after the pandemic H1N1 influenza vaccination campaign in 2009-2010. The H1N1 vaccine - narcolepsy connection is based on observational studies that are prone to various biases, e.g., confounding by H1N1 infection, and ascertainment, recall and selection biases. A direct pathogenic link has, however, remained elusive. We conducted a systematic review and meta-analysis to analyze the magnitude of H1N1 vaccination related risk and to examine if there was any association with H1N1 infection itself. We searched all articles from PubMed, Web of Science and Scopus, and other relevant sources reporting the incidence and risk of post-vaccine narcolepsy. In our paper, we show that the risk appears to be limited to only one vaccine (Pandemrix^®). During the first year after vaccination, the relative risk of narcolepsy was increased 5 to 14-fold in children and adolescents and 2 to 7-fold in adults. The vaccine attributable risk in children and adolescents was around 1 per 18,400 vaccine doses. Studies from Finland and Sweden also appear to demonstrate an extended risk of narcolepsy into the second year following vaccination, but such conclusions should be interpreted with a word of caution due to possible biases. Benefits of immunization outweigh the risk of vaccination-associated narcolepsy, which remains a rare disease.

The immunogenetics of narcolepsy associated with A(H1N1)pdm09 vaccination (Pandemrix) supports a potent gene-environment interaction

The influenza A(H1N1)pdm09 vaccination campaign from 2009 to 2010 was associated with a sudden increase in the incidence of narcolepsy in several countries. Narcolepsy with cataplexy is strongly associated with the human leukocyte antigen (HLA) class II DQB1*06:02 allele, and protective associations with the DQB1*06:03 allele have been reported. Several non-HLA gene loci are also associated, such as common variants of the T-cell receptor-α (TRA), the purinergic receptor P2RY11, cathepsin H (CTSH) and TNFSF4/OX40L/CD252. In this retrospective multicenter study, we investigated if these predisposing gene loci were also involved in vaccination-associated narcolepsy. We compared HLA- along with single-nucleotide polymorphism genotypes for non-HLA regions between 42 Pandemrix-vaccinated narcolepsy cases and 1990 population-based controls. The class II gene loci associations supported previous findings. Nominal association (P-value<0.05) with TRA as well as suggestive (P-value<0.1) associations with P2RY11 and CTSH were found. These associations suggest a very strong gene-environment interaction, in which the influenza A(H1N1)pdm09 strain or Pandemrix vaccine can act as potent environmental triggers.

Retrospective multicenter matched case-control study on the risk factors for narcolepsy with special focus on vaccinations (including pandemic influenza vaccination) and infections in Germany

OBJECTIVE

Studies associate pandemic influenza vaccination with narcolepsy. In Germany, a retrospective, multicenter, matched case-control study was performed to identify risk factors for narcolepsy, particularly regarding vaccinations (seasonal and pandemic influenza vaccination) and infections (seasonal and pandemic influenza) and to quantify the detected risks.

METHODS

Patients with excessive daytime sleepiness who had been referred to a sleep center between April 2009 and December 2012 for multiple sleep latency test (MSLT) were eligible. Case report forms were validated according to the criteria for narcolepsy defined by the Brighton Collaboration (BC). Confirmed cases of narcolepsy (BC level of diagnostic certainty 1-4a) were matched with population-based controls by year of birth, gender, and place of residence. A second control group was established including patients in whom narcolepsy was definitely excluded (test-negative controls).

RESULTS

A total of 103 validated cases of narcolepsy were matched with 264 population-based controls. The second control group included 29 test-negative controls. A significantly increased odd ratio (OR) to develop narcolepsy (crude OR [cOR] = 3.9, 95% confidence interval [CI] = 1.8-8.5; adjusted OR [aOR] = 4.5, 95% CI = 2.0-9.9) was detected in individuals immunized with pandemic influenza A/H1N1/v vaccine prior to symptoms onset as compared to nonvaccinated individuals. Using test-negative controls, in individuals immunized with pandemic influenza A/H1N1/v vaccine prior to symptoms onset, a nonsignificantly increased OR of narcolepsy was detected when compared to nonvaccinated individuals (whole study population, BC levels 1-4a: cOR = 1.9, 95% CI = 0.5-6.9; aOR = 1.8, 95% CI = 0.3-10.1).

CONCLUSIONS

The findings of this study support an increased risk for narcolepsy after immunization with pandemic influenza A/H1N1/v vaccine.

Narcolepsy

Narcolepsy is a chronic sleep disorder that has a typical onset in adolescence and is characterized by excessive daytime sleepiness, which can have severe consequences for the patient. Problems faced by patients with narcolepsy include social stigma associated with this disease, difficulties in obtaining an education and keeping a job, a reduced quality of life and socioeconomic consequences. Two subtypes of narcolepsy have been described (narcolepsy type 1 and narcolepsy type 2), both of which have similar clinical profiles, except for the presence of cataplexy, which occurs only in patients with narcolepsy type 1. The pathogenesis of narcolepsy type 1 is hypothesized to be the autoimmune destruction of the hypocretin-producing neurons in the hypothalamus; this hypothesis is supported by immune-related genetic and environmental factors associated with the disease. However, direct evidence in support of the autoimmune hypothesis is currently unavailable. Diagnosis of narcolepsy encompasses clinical, electrophysiological and biological evaluations, but simpler and faster procedures are needed. Several medications are available for the symptomatic treatment of narcolepsy, all of which have quite good efficacy and safety profiles. However, to date, no treatment hinders or slows disease development. Improved diagnostic tools and increased understanding of the pathogenesis of narcolepsy type 1 are needed and might lead to therapeutic or even preventative interventions.

Post Tick-Borne Encephalitis Virus Vaccination Narcolepsy with Cataplexy

STUDY OBJECTIVES

Narcolepsy with cataplexy (NC) is a chronic neurological disorder thought to result from an altered immune response based on a genetic predisposition coupled with environmental factors. Pandemrix vaccination has been reported to increase the risk of narcolepsy. We aimed at identifying other vaccines associated with the onset of narcolepsy.

METHODS

Case series and retrospective database study.

RESULTS

We identified four cases of NC following a tick-borne encephalitis (TBE) vaccination with FSME Immun. Additional four cases could be detected in the database of the Paul-Ehrlich-Institut, Federal Institute for Vaccines and Biomedicines in Germany.

CONCLUSIONS

Our findings implicate TBE vaccination as a potential additional environmental factor for the development of NC and add additional evidence for an immunological mechanism in the pathogenesis of the disease.

The safety of influenza vaccines in children: An Institute for Vaccine Safety white paper

Most influenza vaccines are generally safe, but influenza vaccines can cause rare serious adverse events. Some adverse events, such as fever and febrile seizures, are more common in children than adults. There can be differences in the safety of vaccines in different populations due to underlying differences in genetic predisposition to the adverse event. Live attenuated vaccines have not been studied adequately in children under 2 years of age to determine the risks of adverse events; more studies are needed to address this and several other priority safety issues with all influenza vaccines in children. All vaccines intended for use in children require safety testing in the target age group, especially in young children. Safety of one influenza vaccine in children should not be extrapolated to assumed safety of all influenza vaccines in children. The low rates of adverse events from influenza vaccines should not be a deterrent to the use of influenza vaccines because of the overwhelming evidence of the burden of disease due to influenza in children.

From discovery to licensure, the Adjuvant System story

Adjuvants are substances added to vaccines to improve their immunogenicity. Used for more than 80 years, aluminum, the first adjuvant in human vaccines, proved insufficient to develop vaccines that could protect against new challenging pathogens such as HIV and malaria. New adjuvants and new combinations of adjuvants (Adjuvant Systems) have opened the door to the delivery of improved and new vaccines against re-emerging and difficult pathogens. Adjuvant Systems concept started through serendipity. The access to new developments in technology, microbiology and immunology have been instrumental for the dicephering of what they do and how they do it. This knowledge opens the door to more rational vaccine design with implications for developing new and better vaccines.