Immunocyte single cell analysis of vaccine-induced narcolepsy.

Increased incidence of narcolepsy type 1 (NT1) was observed following Pandemrix®-vaccination, initiated as a preventive measure against the 2009 Influenza pandemic. Here, single cell analysis was conducted to suggest a lower number of CD8+ CD27+ T cells among these patients. These findings provide understanding into the autoimmune pathogenesis of NT1.

Heterogeneity in Estimates of Incidence and Prevalence of Narcolepsy: A Systematic Review and Meta-Regression Analysis.

INTRODUCTION: Narcolepsy is a chronic neurological disorder. The diagnostic criteria of narcolepsy evolve from clinical symptoms to molecular biomarkers, along with the understanding of its clinical nature and pathogenesis. Estimates of incidence and prevalence of narcolepsy vary between studies, while the contribution of changing diagnostic criteria to the variation remains unclear. We aimed to explore sources of heterogeneity in estimates of incidence and prevalence, with a particular focus on diagnostic criteria. METHODS: We searched 5 databases for observational studies on the incidence or prevalence of narcolepsy published before October 14, 2021. Subgroup analyses and meta-regression were used to assess the impact of diagnostic criteria on incidence/prevalence of narcolepsy after adjusting for age-group, region, study period, vaccination status, index date, and type of narcolepsy. RESULTS: Thirty-five studies were selected from 2,833 articles. The estimates of incidence and prevalence were wide-ranging with high heterogeneity (incidence I2 = 99.8%; prevalence I2 = 99.7%), from 0.06 to 6.56 per 100,000 person-years for incidence and from 1.05 to 79.40 per 100,000 population for prevalence, respectively. Totally 10 diagnostic criteria were used, including the 1st revised edition of International Classification of Diseases (ICSD-1), ICSD-2, ICSD-3, the 8th revision of International Classification of Diseases (ICD-8), ICD-9, ICD-10, Brighton collaboration case definition (Brighton), Mayo classification, the Ullanlinna Narcolepsy Scale, and clinical symptoms with the multiple sleep latency test. ICD tended to provide higher estimates of incidence/prevalence than Brighton (incidence odds ratio [OR] 1.38, [95% CI: 1.02, 1.86]; prevalence OR 1.50, [95% CI: 1.04, 2.39]). No significant difference was found in estimates of two rates between ICSD and Brighton. The incidence was higher for children than adults (OR 1.61, [95% CI: 1.25, 2.07]) and for individuals vaccinated with Pandemrix than those unvaccinated (OR 6.49, [95% CI: 3.86, 10.91]). CONCLUSIONS: Estimates of incidence/prevalence of narcolepsy could not be pooled reliably with substantial heterogeneity. Incidence/prevalence studies using ICSD and Brighton provided lower estimates than studies using ICD and other criteria. Diagnostic criteria should be standardized when comparing or pooling the incidence/prevalence to understand the epidemiology of narcolepsy. Future studies are needed to focus on the at-risk population for the etiology investigation of narcolepsy.

Reassessment of the risk of narcolepsy in children in England 8 years after receipt of the AS03-adjuvanted H1N1 pandemic vaccine: A case-coverage study.

BACKGROUND: Early studies of narcolepsy after AS03-adjuvanted pandemic A/H1N12009 vaccine (Pandemrix) could not define the duration of elevated risk post-vaccination nor the risk in children aged under 5 years who may not present until much older. METHODS/FINDINGS: Clinical information and sleep test results, extracted from hospital notes at 3 large pediatric sleep centers in England between September 2017 and June 2018 for narcolepsy cases aged 4-19 years with symptom onset since January 2009, were reviewed by an expert panel to confirm the diagnosis. Vaccination histories were independently obtained from general practitioners (GPs). The odds of vaccination in narcolepsy cases compared with the age-matched English population was calculated after adjustment for clinical conditions that were indications for vaccination. GP questionnaires were returned for 242 of the 244 children with confirmed narcolepsy. Of these 5 were under 5 years, 118 were 5-11 years, and 119 were 12-19 years old at diagnosis; 39 were vaccinated with Pandemrix before onset. The odds ratio (OR) for onset at any time after vaccination was 1.94 (95% confidence interval [CI] 1.30-2.89), The elevated risk period was restricted to onsets within 12 months of vaccination (OR 6.65 [3.44-12.85]) and was highest within the first 6 months. After one year, ORs were not significantly different from 1 up to 8 years after vaccination. The ORs were similar in under five-year-olds and older ages. The estimated attributable risk was 1 in 34,500 doses. Our study is limited by including cases from only 3 sleep centers, who may differ from cases diagnosed in nonparticipating centers, and by imprecision in defining the centers' catchment population. The potential for biased recall of onset shortly after vaccination in cases aware of the association cannot be excluded. CONCLUSIONS: In this study, we found that vaccine-attributable cases have onset of narcolepsy within 12 months of Pandemrix vaccination. The attributable risk is higher than previously estimated in England because of identification of vaccine-attributable cases with late diagnoses. Absence of a compensatory drop in risk 1-8 years after vaccination suggests that Pandemrix does not trigger onsets in those in whom narcolepsy would have occurred later.

Predictors of narcolepsy and hypersomnia due to medical disorder in pediatric craniopharyngioma.

PURPOSE: Several studies describe sleep-wake disturbances in pediatric craniopharyngioma, but none have determined the prevalence or associated predictors of excessive sleepiness in this group after diagnosis and prior to post-operative observation or adjuvant radiotherapy. In this study, we report sleep-wake disturbances in children and adolescents with craniopharyngioma and associated clinical and treatment variables. METHODS: After surgery and prior to radiotherapy or observation, pediatric patients (n = 110) with craniopharyngioma ≥ 3 years old completed a baseline sleep clinic evaluation by a pediatric sleep specialist, polysomnography (PSG) and next-day multiple sleep latency test (MSLT). MSLT was limited to those ≥ 6 years old. Logistic regression models were used to determine the relationship between patient characteristics and the presence and type of hypersomnia. RESULTS: Amongst patients completing PSG and MSLT, 80% had polygraphic evidence of excessive daytime sleepiness. Hypersomnia due to medical condition was diagnosed in 45% and narcolepsy in 35%. Overweight or obese patients were more likely to be diagnosed with hypersomnia (P = 0.012) or narcolepsy (P = 0.009). Grade 2 hypothalamic involvement (HI) at diagnosis was associated with the diagnosis of narcolepsy (P = 0.0008). CONCLUSIONS: This study describes the prevalence and associated predictors of hypersomnia for patients with craniopharyngioma after surgical resection. HI was predictive of narcolepsy diagnosis, and a higher body mass index z-score was associated with hypersomnia due to medical condition and narcolepsy. We recommend that sleep assessment and intervention begin after surgical resection, especially in overweight or obese patients and those with extensive tumors.

Symptomatic Narcolepsy/Cataplexy in a Dog with Brainstem Meningoencephalitis of Unknown Origin.

A 4 yr old, intact female cocker spaniel was presented for investigation of acute, progressive lethargy/hypersomnia; vestibular signs; and cataplexy. A narcolepsy-cataplexy episode with associated hypertension and bradycardia was triggered during examination. There was no evidence of arrhythmia on electrocardiography during the episode. Hematology, serum biochemistry, and thoracic and abdominal imaging were unremarkable. MRI of the brain and cerebrospinal fluid analysis were compatible with meningoencephalitis of unknown origin affecting the mesencephalon, pons and rostral medulla oblongata. The dog was started on immunosuppressive treatment with prednisolone and cytosine arabinoside, which was subsequently switched to cyclosporine. Narcolepsy-cataplexy episodes could initially still be triggered by offering food; however, they gradually became shorter and less frequent until they completely subsided along with all other clinical signs after 3 wk. No relapse occurred over a 32 mo follow-up period from the diagnosis. Repeated MRI revealed marked reduction in the lesion size; cerebrospinal fluid analysis revealed no abnormalities. Although very rare, symptomatic narcolepsy/cataplexy can occur in dogs and can be secondary to brainstem encephalitis. Cardiovascular changes can occur in association with narcolepsy/cataplexy and should be considered when dealing with patients presenting with these specific clinical signs.

Change in risk for narcolepsy over time and impact of definition of onset date following vaccination with AS03 adjuvanted pandemic A/H1N1 influenza vaccine (Pandemrix) during the 2009 H1N1 influenza pandemic.

PURPOSE: To estimate risk for narcolepsy in defined time windows following exposure to adjuvanted A(H1N1) pandemic vaccine (Pandemrix) and impact of different definitions of index date for the narcolepsy diagnosis. METHODS: Vaccine exposure in approximately 30% of the Swedish population in 2009 was linked to information on narcolepsy diagnosis retrieved from the national patient registry. Cases were verified by a systematic chart review. Poisson regression was used to compare incidence in defined time windows following vaccination. RESULTS: Of 266 cases of narcolepsy identified, 25% (66/266) were prevalent cases with symptom onset documented before vaccine exposure. Incident cases had a median time interval between first symptom and the date recorded in the patient registry of 64 weeks (IQR 39-107) when vaccinated (N = 182) and 65 weeks (IQR 51-72) when unvaccinated (N = 16). With first symptom defining index date, the adjusted risk for narcolepsy in younger patients was increased 14 times during the first year after vaccination, three times elevated the second year, but with no detectable increased risk more than 2 years after vaccination exposure. Using the index date from the patient registry, the adjusted increase in risk was about seven times elevated for all three time intervals. CONCLUSIONS: The magnitude of the estimated increased risk for narcolepsy following exposure to the A(H1N1) pandemic vaccine is highly dependent on the method used to determine the index date for disease onset. The sometimes very long and potentially variable interval from first symptom to a health care registry diagnosis complicates estimations of risk.

[False beliefs about vaccines]. / Falsas creencias sobre las vacunas.

Vaccines are an essential tool for the prevention of infectious diseases. However, false ideas and rumours with no scientific foundation about their possible negative effects may dissuade people from being vaccinated, with the consequent risks for the health of the population. The objective of this article is to evaluate the origin and the arguments of some of the most frequent mistaken ideas and rumours about the possible adverse effects of vaccines. Some clearly established adverse effects are presented, as well as false beliefs about various vaccines and potential harm to health. Vaccines, like any drug, can cause adverse effects, but the possible adverse effects of vaccination programs are clearly lower than their individual (vaccinated) and collective benefits (those vaccinated and those who cannot be vaccinated for medical reasons). The possible adverse effects attributable to vaccines should be detected by powerful and well-structured pharmacovigilance systems.

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.

Epidemiology and Pathophysiology of Childhood Narcolepsy.

It is now recognized that there are two types of narcolepsy. Narcolepsy type I or Narcolepsy with cataplexy is caused by the loss of hypocretin or orexin neurons. Narcolepsy type II or narcolepsy without cataplexy has normal hypocretin and the etiology is unknown. Hypocretin is a neuropeptide produced by neurons in the lateral hypothalamus. Both genetic and environmental factors play a crucial role in the pathogenesis of narcolepsy. Most patients with narcolepsy type I and half of patients with narcolepsy type II carry HLA-DQB1*0602. HLA-DQB1*0602 forms a heterodimer with HLA-DQA1*0102 and may act as an antigen presenter to the T cell receptors, resulting in narcolepsy susceptibility. In addition, narcolepsy has been shown to be linked to polymorphisms in other non-HLA genes that may affect immune regulatory function, leading to speculation that autoimmune processes may play a crucial role in the loss of hypocretin neurons. Infections have been proposed as a potential trigger for the autoimmune-mediated mechanism. Several recent studies have shown increased cases of narcolepsy, especially in children and adolescents in relation with H1N1 influenza. The increased cases in Europe seems to be related to a specific type of H1N1 influenza vaccination (Pandemrix), while the increased cases in China are related to influenza infection. The data from the Pediatric Working Group of the Sleep Research Network have shown similar increases of early onset narcolepsy in the United States.

Quality of life and trust among young people with narcolepsy and their families, after the Pandemrix® vaccination: protocol for a case-control study.

BACKGROUND: The extensive vaccination programme against swine flu resulted in an increased incidence of narcolepsy among children and adolescents. There is a need to explore if these young persons' experiences have affected their trust in healthcare, their willingness to participate in future prevention programmes, and their contacts with the healthcare system. The overall aim is to identify factors important for the life-situation of children and adolescents with narcolepsy and their families, and factors that correlate with trust in healthcare. METHODS/DESIGN: Data will be collected via questionnaires from all available children with narcolepsy following the vaccination and their families, as well as a control group of children with diabetes and their families. Longitudinal descriptive interviews will also be conducted with a selection of 20-25 children and their families. Techniques from media research will be used for Internet-based data collection and analysis of information relating to narcolepsy from social media. DISCUSSION: This project will use the situation of young persons with narcolepsy after the swine flu vaccination as a case to build a model that can be used in situations where trust in healthcare is essential. This model will be based on findings from the included studies on how trust is influenced by support, quality of life, burden of disease, impact on family, and use of social media. The model developed in this project will be beneficial in future situations where trust in healthcare is essential, such as new pandemic outbreaks but also for "everyday" adherence to health advice.

Environmental factors in the etiology of type 1 diabetes, celiac disease, and narcolepsy.

The etiology of human leukocyte antigen (HLA)-associated organ-specific autoimmune diseases is incomplete. In type 1 diabetes and celiac disease, the strongest associations are with the HLA-DR3-DQ2 and DR4-DQ8 haplotypes, whereas the DQB1*06:02 allele has a strong negative association. In contrast, narcolepsy, especially as recently triggered by the Pandemrix(®) H1N1 vaccine (GlaxoKlineSmith (GSK), Brentford, Middlesex, UK), did not seem to develop without at least one copy of the latter allele. The overall hypothesis is that the role of these different HLA haplotypes, especially in Finland and Sweden, is related to the immune response to infectious agents that are common in these two populations. The high incidence of both type 1 diabetes and celiac disease in Scandinavia may be the result of the HLA-DR3-DQ2 and DR4-DQ8 haplotypes, and the DQB1*06:02 allele are common because they protected people from succumbing to common infections. The timing of dissecting the autoimmune response is critical to understand the possible role of environmental factors. First, an etiological trigger may be a common virus infecting beta cells or with antigens inducing beta-cell cross reactivity. Second, an autoimmune reaction may ensue, perhaps in response to beta-cell apoptosis or autophagy, resulting in autoantigen-specific T cells and autoantibodies. It is critical in at-risk children to dissect the immune response prior to the appearance of autoantibodies in order to identify cellular reactions in response to environmental factors that are able to induce an HLA-associated immune reaction.

Where are we in our understanding of the association between narcolepsy and one of the 2009 adjuvanted influenza A (H1N1) vaccines?

Evaluating new rare serious vaccine safety signals is difficult and complex work. To further assess the observed increase in narcolepsy cases seen in Europe with the 2009 pandemic H1N1 influenza vaccine, the International Alliance for Biological Standardization (IABS) invited a wide range of experts to a one day meeting in Geneva in October 2015 to present data and to discuss the implications. The presentations covered the following topics: clinical picture of childhood narcolepsy following the 2009 H1N1 pandemic vaccination campaigns; epidemiological studies conducted to assess the risk of narcolepsy, other neurological and immune-related diseases following 2009 pandemic H1N1 influenza vaccine; potential biases influencing the different epidemiological study designs; potential genetic contribution to the development of narcolepsy; potential biological mechanisms for development of narcolepsy in this setting including the role of the virus itself, antigenic differences between the vaccines and differences in AS03-adjuvanted vaccines. The presentations were followed by fulsome roundtable discussions. Members from affected families also attended and made informal comments to round out the day's deliberations. This meeting emphasized the value added in bringing together in a neutral setting a wide range of experts and vaccine producers to discuss such a complex new serious adverse event following immunization.

Post-H1N1 Flu Vaccination Narcolepsy in Switzerland: A Retrospective Survey in the 30 Sleep-Certified Swiss Centers.

Narcolepsy-cataplexy is a sleep-wake disorder and suggested to be immune-mediated, involving genetic and environmental factors. The autoimmune process eventually leads to a loss of hypocretin neurons in the lateral hypothalamus. Epidemiological studies in several countries proved an increased incidence of narcolepsy after H1N1 flu vaccination and infection. This survey in 30 sleep centers in Switzerland led to the identification of 9 H1N1-vaccinated children and adults as newly diagnosed narcolepsy. Clinical features included the abrupt and severe onset of sleepiness, cataplexy and sleep fragmentation.

The Safety of Adjuvanted Vaccines Revisited: Vaccine-Induced Narcolepsy.

Despite the very high benefit-to-risk ratio of vaccines, the fear of negative side effects has discouraged many people from getting vaccinated, resulting in the reemergence of previously controlled diseases such as measles, pertussis and diphtheria. This fear has been amplified more recently by multiple epidemiologic studies that confirmed the link of an AS03-adjuvanted pandemic influenza vaccine (Pandemrix, GlaxoSmithKline Biologicals, Germany) used in Europe during the 2009 H1N1 influenza pandemic [A(H1N1) pdm09] with the development of narcolepsy, a chronic sleep disorder, in children and adolescents. However, public misperceptions of what adjuvants are and why they are used in vaccines has created in some individuals a closed "black box" attitude towards all vaccines. The focus of this review article is to revisit this "black box" using the example of narcolepsy associated with the European AS03-adjuvanted pandemic influenza vaccine.

Sleep assessments for a mild traumatic brain injury trial in a military population.

Baseline sleep characteristics were explored for 71 U.S. military service members with mild traumatic brain injury (mTBI) enrolled in a post-concussive syndrome clinical trial. The Pittsburgh Sleep Quality Index (PSQI), sleep diary, several disorder-specific questionnaires, actigraphy and polysomnographic nap were collected. Almost all (97%) reported ongoing sleep problems. The mean global PSQI score was 13.5 (SD=3.8) and 87% met insomnia criteria. Sleep maintenance efficiency was 79.1% for PSQI, 82.7% for sleep diary and 90.5% for actigraphy; total sleep time was 288, 302 and 400 minutes, respectively. There was no correlation between actigraphy and subjective questionnaires. Overall, 70% met hypersomnia conditions, 70% were at high risk for obstructive sleep apnea (OSA), 32% were symptomatic for restless legs syndrome, and 6% reported cataplexy. Nearly half (44%) reported coexisting insomnia, hypersomnia and high OSA risk. Participants with post-traumatic stress disorder (PTSD) had higher PSQI scores and increased OSA risk. Older participants and those with higher aggression, anxiety or depression also had increased OSA risk. The results confirm poor sleep quality in mTBI with insomnia, hypersomnia, and OSA risk higher than previously reported, and imply sleep disorders in mTBI may be underdiagnosed or exacerbated by comorbid PTSD.

HLA dosage effect in narcolepsy with cataplexy.

Narcolepsy with cataplexy is a sleep disorder caused by the loss of hypocretin-producing neurons in the hypothalamus. It is tightly associated with a specific human leukocyte antigen (HLA)-allele: HLA-DQB1*06:02. Based on this, an autoimmune process has been hypothesized. A functional HLA-DQ molecule consists of a DQα and a DQß chain. HLA-DQB1*06:02 (DQß) has a strong preference for binding to HLA-DQA1*01:02 (DQα), and together they form the functional DQ0602 dimer. A dosage effect would be expected if the HLA-DQ0602 dimer itself is directly involved in the aetiology. An increased expression of the HLA-DQ0602 dimer is expected in individuals homozygous for HLA-DQB1*06:02-DQA1*01:02, but is also hypothesized in individuals heterozygous for HLA-DQB1*06:02 and homozygous for HLA-DQA1*01:02. To study the impact of the expression of the HLA-DQ0602 dimer on narcolepsy susceptibility, 248 Dutch narcolepsy patients and 1272 Dutch control subjects, all of them positive for DQB1*06:02 (heterozygous and homozygous), were HLA-genotyped with attention not only to DQB1 but also to DQA1*01:02. DQB1*06:02-DQA1*01:02 homozygosity was significantly more often seen in patients compared to controls (O.R. 2.29) confirming previous observations. More importantly, a significantly higher prevalence of homozygosity for DQA1*01:02 was found in HLA-DQB1*06:02 heterozygous patients compared to controls (O.R. 2.37, p < 0.001). The latter finding clearly supports a direct role of the HLA-DQ molecule in the development of disease.

A coordinated cross-disciplinary research initiative to address an increased incidence of narcolepsy following the 2009-2010 Pandemrix vaccination programme in Sweden.

In response to the 2009-2010 influenza A(H1N1)pdm09 pandemic, a mass vaccination programme with the AS03-adjuvanted influenza A(H1N1) vaccine Pandemrix was initiated in Sweden. Unexpectedly, there were a number of narcolepsy cases amongst vaccinated children and adolescents reported. In this review, we summarize the results of a joint cross-disciplinary national research effort to investigate the adverse reaction signal from the spontaneous reporting system and to better understand possible causative mechanisms. A three- to fourfold increased risk of narcolepsy in vaccinated children and adolescents was verified by epidemiological studies. Of importance, no risk increase was observed for the other neurological and autoimmune diseases studied. Genetic studies confirmed the association with the allele HLA-DQB1*06:02, which is known to be related to sporadic narcolepsy. Furthermore, a number of studies using cellular and molecular experimental models investigated possible links between influenza vaccination and narcolepsy. Serum analysis, using a peptide microarray platform, showed that individuals who received Pandemrix exhibited a different epitope reactivity pattern to neuraminidase and haemagglutinin, as compared to individuals who were infected with H1N1. Patients with narcolepsy were also found to have increased levels of interferon-gamma production in response to streptococcus-associated antigens. The chain of patient-related events and the study results emerging over time were subjected to intense nationwide media attention. The importance of transparent communication and collaboration with patient representatives to maintain public trust in vaccination programmes is also discussed in the review. Organizational challenges due to this unexpected event delayed the initiation of some of the research projects, still the main objectives of this joint, cross-disciplinary research effort were reached, and important insights were acquired for future, similar situations in which a fast and effective task force may be required to evaluate vaccination-related adverse events.

Autoantibodies against ganglioside GM3 are associated with narcolepsy-cataplexy developing after Pandemrix vaccination against 2009 pandemic H1N1 type influenza virus.

Following the mass vaccinations against pandemic influenza A/H1N1 virus in 2009, a sudden increase in juvenile onset narcolepsy with cataplexy (NC) was detected in several European countries where AS03-adjuvanted Pandemrix vaccine had been used. NC is a chronic neurological disorder characterized by excessive daytime sleepiness and cataplexy. In human NC, the hypocretin-producing neurons in the hypothalamus or the hypocretin signaling pathway are destroyed by an autoimmune reaction. Both genetic (e.g. HLA-DQB1*0602) and environmental risk factors (e.g. Pandemrix) contribute to the disease development, but the underlying and the mediating immunological mechanisms are largely unknown. Influenza virus hemagglutinin is known to bind gangliosides, which serve as host cell virus receptors. Anti-ganglioside antibodies have previously been linked to various neurological disorders, like the Guillain-Barré syndrome which may develop after infection or vaccination. Because of these links we screened sera of NC patients and controls for IgG anti-ganglioside antibodies against 11 human brain gangliosides (GM1, GM2, GM3, GM4, GD1a, GD1b, GD2, GD3, GT1a, GT1b, GQ1b) and a sulfatide by using a line blot assay. Samples from 173 children and adolescents were analyzed: 48 with Pandemrix-associated NC, 20 with NC without Pandemrix association, 57 Pandemrix-vaccinated and 48 unvaccinated healthy children. We found that patients with Pandemrix-associated NC had more frequently (14.6%) anti-GM3 antibodies than vaccinated healthy controls (3.5%) (P = 0.047). Anti-GM3 antibodies were significantly associated with HLA-DQB1*0602 (P = 0.016) both in vaccinated NC patients and controls. In general, anti-ganglioside antibodies were more frequent in vaccinated (18.1%) than in unvaccinated (7.3%) individuals (P = 0.035). Our data suggest that autoimmunity against GM3 is a feature of Pandemrix-associated NC and that autoantibodies against gangliosides were induced by Pandemrix vaccination.

Comparison of Pandemrix and Arepanrix, two pH1N1 AS03-adjuvanted vaccines differentially associated with narcolepsy development.

Narcolepsy onset in children has been associated with the 2009 influenza A H1N1 pandemic and vaccination with Pandemrix. However it was not clearly observed with other adjuvanted pH1N1 vaccines such as Arepanrix or Focetria. Our aim was to characterize the differences between Pandemrix and Arepanrix that might explain the risk for narcolepsy after Pandemrix vaccination using 2D-DIGE and mass spectrometry (MS). We found that Pandemrix (2009 batch) and Arepanrix (2010 batch) showed 5 main viral proteins: hemagglutinin HA1 and HA2 subunits, neuraminidase NA, nucleoprotein NP, and matrix protein MA1 and non-viral proteins from the Gallus gallus growth matrix used in the manufacturing of the vaccines. Latticed patterns of HA1, HA2 and NA indicated charge and molecular weight heterogeneity, a phenomenon likely caused by glycosylation and sulfation. Overall, Pandemrix contained more NP and NA, while Arepanrix displayed a larger diversity of viral and chicken proteins, with the exception of five chicken proteins (PDCD6IP, TSPAN8, H-FABP, HSP and TUB proteins) that were relatively more abundant in Pandemrix. Glycosylation patterns were similar in both vaccines. A higher degree of deamidation and dioxidation was found in Pandemrix, probably reflecting differential degradation across batches. Interestingly, HA1 146N (residue 129N in the mature protein) displayed a 10-fold higher deamidation in Arepanrix versus Pandemrix. In recent vaccine strains and Focetria, 146N is mutated to D which is associated with increased production yields suggesting that 146N deamidation may have also occurred during the manufacturing of Arepanrix. The presence of 146N in large relative amounts in Pandemrix and the wild type virus and in lower relative quantities in Arepanrix or other H1N1 vaccines may have affected predisposition to narcolepsy.