Dengue virus IgG and serotype-specific neutralizing antibody titers measured with standard and mature viruses are associated with protection.

Recent work demonstrates the limitations of the standard dengue virus (DENV) neutralization assay to predict protection against dengue. We perform studies to compare how a commercial IgG ELISA, envelope domain III (EDIII) or non-structural protein 1 (NS1) binding antibodies, and titers from plaque reduction neutralization tests (PRNTs) using reference standard and clinical mature viruses are associated with dengue disease. Healthy children (n = 1,206) in Cebu, Philippines were followed for 5 years. High ELISA values (≥3) were associated with reduced dengue probability relative to naïve children (3% vs. 10%, p = 0.008), but antibody binding EDIII or NS1 from each serotype had no association. High standard and mature geometric mean PRNT titers were associated with reduced dengue disease overall (p < 0.01), and high DENV2 and DENV3 titers in both assays provided protection against the matched serotype (p < 0.02). However, while 52% of dengue cases had standard virus PRNT titers > 100, only 2% of cases had mature virus PRNT titers > 100 (p < 0.001), indicating a lower, more consistent threshold for protection. Each assay may be useful for different purposes as correlates of protection in population and vaccine trials.

Effect of single-dose, live, attenuated dengue vaccine in children with or without previous dengue on risk of subsequent, virologically confirmed dengue in Cebu, the Philippines: a longitudinal, prospective, population-based cohort study.

BACKGROUND: A three-dose dengue vaccine (CYD-TDV) was licensed for use in children aged 9 years and older starting in 2015 in several dengue-endemic countries. In 2016, the Philippine Department of Health implemented a dengue vaccination programme, which was discontinued because of safety concerns. We assessed the relative risk of developing virologically confirmed dengue among children who did or did not receive a single dose of CYD-TDV by previous dengue virus (DENV) infections at baseline classified as none, one, and two or more infections. METHODS: In this longitudinal, prospective, population-based cohort study, we enrolled healthy children (aged 9-14 years) residing in Bogo or Balamban, Cebu, Philippines, between May 2, and June 2, 2017, before a mass dengue vaccination campaign, via the Rural Health Unit in Bogo and three Rural Health Units in Balamban. We collected demographic information and sera for baseline DENV serostatus and conducted active surveillance for acute febrile illness. Children who developed acute febrile illness were identified, clinical data were collected, and blood was drawn for confirmation of dengue by RT-PCR. The primary outcome was the relative risk of developing virologically confirmed dengue among children who received or did not receive a single dose of CYD-TDV by DENV serostatus at baseline. FINDINGS: A single dose of CYD-TDV did not confer protection against virologically confirmed dengue in children who had none or one previous DENV infection at baseline. One dose conferred significant protection against hospital admission for virologically confirmed dengue among participants who had two or more previous DENV infections at baseline during the first 3 years (70%, 95% CI 20-88; p=0·017) and the entire follow-up period (67%, 19-87; p=0·016). INTERPRETATION: The risk of developing virologically confirmed dengue after a single dose of CYD-TDV varied by baseline DENV serostatus. Since the study assessed the effect of only a single dose, the findings cannot inform decisions on vaccination by public health officers. However, the findings have implications for children who receive an incomplete vaccination regimen and these results should prompt more detailed analyses in future trials on dengue vaccines. FUNDING: The Philippine Department of Health, Hanako Foundation, WHO, Swedish International Development Cooperation Agency, International Vaccine Institute, University of North Carolina, and US National Institute of Allergy and Infectious Diseases.

Evidence supports a causal association between allele-specific vitamin D receptor binding and multiple sclerosis among Europeans.

Although evidence exists for a causal association between 25-hydroxyvitamin D (25(OH)D) serum levels, and multiple sclerosis (MS), the role of variation in vitamin D receptor (VDR) binding in MS is unknown. Here, we leveraged previously identified variants associated with allele imbalance in VDR binding (VDR-binding variant; VDR-BV) in ChIP-exo data from calcitriol-stimulated lymphoblastoid cell lines and 25(OH)D serum levels from genome-wide association studies to construct genetic instrumental variables (GIVs). GIVs are composed of one or more genetic variants that serve as proxies for exposures of interest. Here, GIVs for both VDR-BVs and 25(OH)D were used in a two-sample Mendelian Randomization study to investigate the relationship between VDR binding at a locus, 25(OH)D serum levels, and MS risk. Data for 13,598 MS cases and 38,887 controls of European ancestry from Kaiser Permanente Northern California, Swedish MS studies, and the UK Biobank were included. We estimated the association between each VDR-BV GIV and MS. Significant interaction between a VDR-BV GIV and a GIV for serum 25OH(D) was evidence for a causal association between VDR-BVs and MS unbiased by pleiotropy. We observed evidence for associations between two VDR-BVs (rs2881514, rs2531804) and MS after correction for multiple tests. There was evidence of interaction between rs2881514 and a 25(OH)D GIV, providing evidence of a causal association between rs2881514 and MS. This study is the first to demonstrate evidence that variation in VDR binding at a locus contributes to MS risk. Our results are relevant to other autoimmune diseases in which vitamin D plays a role.

Local Ancestry at the Major Histocompatibility Complex Region is Not a Major Contributor to Disease Heterogeneity in a Multiethnic Lupus Cohort.

OBJECTIVE: Systemic lupus erythematosus (SLE) is an autoimmune disease resulting in debilitating clinical manifestations that vary in severity by race and ethnicity with a disproportionate burden in African American, Mestizo, and Asian populations compared with populations of European descent. Differences in global and local genetic ancestry may shed light on the underlying mechanisms contributing to these disparities, including increased prevalence of lupus nephritis, younger age of symptom onset, and presence of autoantibodies. METHODS: A total of 1,139 European, African American, and Mestizos patients with SLE were genotyped using the Affymetrix LAT1 World array. Global ancestry proportions were estimated using ADMIXTURE, and local ancestry was estimated using RFMIXv2.0. We investigated associations between lupus nephritis, age at onset, and autoantibody status with both global and local ancestry proportions within the Major Histocompatibility Complex region. RESULTS: Our results showed small effect sizes that did not meet the threshold for statistical significance for global or local ancestry proportions in either African American or Mestizo patients with SLE who presented with the clinical manifestations of interest compared with those who did not. CONCLUSION: These findings suggest that local genetic ancestry within the Major Histocompatibility Complex region is not a major contributor to these SLE manifestations among patients with SLE from admixed populations.

Dietary fibre confers therapeutic effects in a preclinical model of Huntington's disease.

Huntington's disease (HD) is a neurodegenerative disorder involving psychiatric, cognitive and motor deficits, as well as peripheral symptoms, including gastrointestinal dysfunction. The R6/1 HD mouse model expresses a mutant human huntingtin transgene and has been shown to provide an accurate disease model. Recent evidence of gut microbiome disruption was shown in preclinical and clinical HD. Therefore, we aimed to assess the potential role of gut microbial modulation in the treatment of HD. The R6/1 HD mice and wild-type littermate controls were randomised to receive diets containing different amounts of fibre: high-fibre (10 % fibre), control (5 % fibre), or zero-fibre (0 % fibre), from 6 to 20 weeks of age. We characterized the onset and progression of motor, cognitive and affective deficits, as well as gastrointestinal function and gut morphological changes. Faeces were collected for gut microbiome profiling using 16S rRNA sequencing, at 14 and 20 weeks of age. When compared to the control diet, high-fibre diet improved the performance of HD mice in behavioral tests of cognitive and affective function, as well as the gastrointestinal function of both HD and wild-type mice. While the diets changed the beta diversity of wild-type mice, no statistical significance was observed at 14 or 20 weeks of age within the HD mice. Analysis of Composition of Microbiomes with Bias Correction (ANCOM-BC) models were performed to evaluate microbiota composition, which identified differences, including a decreased relative abundance of the phyla Actinobacteriota, Campylobacterota and Proteobacteria and an increased relative abundance of the families Bacteroidaceae, Oscillospiraceae and Ruminococcaceae in HD mice when compared to wild-type mice after receiving high-fibre diet. PICRUSt2 revealed that high-fibre diet also decreased potentially pathogenic functional pathways in HD. In conclusion, high-fibre intake was effective in enhancing gastrointestinal function, cognition and affective behaviors in HD mice. These findings indicate that dietary fibre interventions may have therapeutic potential in Huntington's disease to delay clinical onset, and have implications for related disorders exhibiting dysfunction of the gut-brain axis.

Homotypic antibodies target novel E glycoprotein domains after natural DENV 3 infection/vaccination.

The envelope (E) glycoprotein is the primary target of type-specific (TS) neutralizing antibodies (nAbs) after infection with any of the four distinct dengue virus serotypes (DENV1-4). nAbs can be elicited to distinct structural E domains (EDs) I, II, or III. However, the relative contribution of these domain-specific antibodies is unclear. To identify the primary DENV3 nAb targets in sera after natural infection or vaccination, chimeric DENV1 recombinant encoding DENV3 EDI, EDII, or EDIII were generated. DENV3 EDII is the principal target of TS polyclonal nAb responses and encodes two or more neutralizing epitopes. In contrast, some were individuals vaccinated with a DENV3 monovalent vaccine-elicited serum TS nAbs targeting each ED in a subject-dependent fashion, with an emphasis on EDI and EDIII. Vaccine responses were also sensitive to DENV3 genotypic variation. This DENV1/3 panel allows the measurement of serum ED TS nAbs, revealing differences in TS nAb immunity after natural infection or vaccination.

Development of the aganglionic colon following surgical rescue in a cell therapy model of Hirschsprung disease in rat.

Patients with Hirschsprung disease lack enteric ganglia in the distal colon and propulsion of colorectal content is substantially impaired. Proposed stem cell therapies to replace neurons require surgical bypass of the aganglionic bowel during re-colonization, but there is inadequate knowledge of the consequences of bypass. We performed bypass surgery in Ednrb-/- Hirschsprung rat pups. Surgically rescued rats failed to thrive, an outcome reversed by supplying electrolyte- and glucose-enriched drinking water. Histologically, the bypassed colon had normal structure, but grew substantially less in diameter than the functional region proximal to the bypass. Extrinsic sympathetic and spinal afferent neurons projected to their normal targets, including arteries and the circular muscle, in aganglionic regions. However, although axons of intrinsic excitatory and inhibitory neurons grew into the aganglionic region, their normally dense innervation of circular muscle was not restored. Large nerve trunks that contained tyrosine hydroxylase (TH)-, calcitonin gene-related peptide (CGRP, encoded by Calca or Calcb)-, neuronal nitric oxide synthase (nNOS or NOS1)-, vasoactive intestinal peptide (VIP)- and tachykinin (encoded by Tac1)-immunoreactive axons occurred in the distal aganglionic region. We conclude that the rescued Ednrb-/- rat provides a good model for the development of cell therapies for the treatment of Hirschsprung disease.

Gene-environment interactions increase the risk of paediatric-onset multiple sclerosis associated with household chemical exposures.

BACKGROUND: We previously reported an association between household chemical exposures and an increased risk of paediatric-onset multiple sclerosis. METHODS: Using a case-control paediatric multiple sclerosis study, gene-environment interaction between exposure to household chemicals and genotypes for risk of paediatric-onset multiple sclerosis was estimated.Genetic risk factors of interest included the two major HLA multiple sclerosis risk factors, the presence of DRB1*15 and the absence of A*02, and multiple sclerosis risk variants within the metabolic pathways of common household toxic chemicals, including IL-6 (rs2069852), BCL-2 (rs2187163) and NFKB1 (rs7665090). RESULTS: 490 paediatric-onset multiple sclerosis cases and 716 controls were included in the analyses. Exposures to insect repellent for ticks or mosquitos (OR 1.47, 95% CI 1.06 to 2.04, p=0.019), weed control products (OR 2.15, 95% CI 1.51 to 3.07, p<0.001) and plant/tree insect or disease control products (OR 3.25, 95% CI 1.92 to 5.49, p<0.001) were associated with increased odds of paediatric-onset multiple sclerosis. There was significant additive interaction between exposure to weed control products and NFKB1 SNP GG (attributable proportions (AP) 0.48, 95% CI 0.10 to 0.87), and exposure to plant or disease control products and absence of HLA-A*02 (AP 0.56; 95% CI 0.03 to 1.08). There was a multiplicative interaction between exposure to weed control products and NFKB1 SNP GG genotype (OR 2.30, 95% CI 1.00 to 5.30) but not for other exposures and risk variants. No interactions were found with IL-6 and BCL-2 SNP GG genotypes. CONCLUSIONS: The presence of gene-environment interactions with household toxins supports their possible causal role in paediatric-onset multiple sclerosis.

Structure and neutralization mechanism of a human antibody targeting a complex Epitope on Zika virus.

We currently have an incomplete understanding of why only a fraction of human antibodies that bind to flaviviruses block infection of cells. Here we define the footprint of a strongly neutralizing human monoclonal antibody (mAb G9E) with Zika virus (ZIKV) by both X-ray crystallography and cryo-electron microscopy. Flavivirus envelope (E) glycoproteins are present as homodimers on the virion surface, and G9E bound to a quaternary structure epitope spanning both E protomers forming a homodimer. As G9E mainly neutralized ZIKV by blocking a step after viral attachment to cells, we tested if the neutralization mechanism of G9E was dependent on the mAb cross-linking E molecules and blocking low-pH triggered conformational changes required for viral membrane fusion. We introduced targeted mutations to the G9E paratope to create recombinant antibodies that bound to the ZIKV envelope without cross-linking E protomers. The G9E paratope mutants that bound to a restricted epitope on one protomer poorly neutralized ZIKV compared to the wild-type mAb, demonstrating that the neutralization mechanism depended on the ability of G9E to cross-link E proteins. In cell-free low pH triggered viral fusion assay, both wild-type G9E, and epitope restricted paratope mutant G9E bound to ZIKV but only the wild-type G9E blocked fusion. We propose that, beyond antibody binding strength, the ability of human antibodies to cross-link E-proteins is a critical determinant of flavivirus neutralization potency.

Identification of Cell-Specific Differential DNA Methylation Associated With Methotrexate Treatment Response in Rheumatoid Arthritis.

OBJECTIVE: We undertook this study to estimate changes in cell-specific DNA methylation (DNAm) associated with methotrexate (MTX) response using whole blood samples collected from rheumatoid arthritis (RA) patients before and after initiation of MTX treatment. METHODS: Patients included in this study were from the Rheumatoid Arthritis Medication Study (n = 66) and the University of California San Francisco Rheumatoid Arthritis study (n = 11). All patients met the American College of Rheumatology RA classification criteria. Blood samples were collected at baseline and following treatment. Disease Activity Scores in 28 joints using the C-reactive protein level were collected at baseline and after 3-6 months of treatment with MTX. Methylation profiles were generated using the Illumina Infinium HumanMethylation450 and MethylationEPIC v1.0 BeadChip arrays using DNA from whole blood. MTX response was defined using the EULAR response criteria (responders showed good/moderate response; nonresponders showed no response). Differentially methylated positions were identified using the Limma software package and Tensor Composition Analysis, which is a method for identifying cell-specific differential DNAm at the CpG level from tissue-level ("bulk") data. Differentially methylated regions were identified using Comb-p software. RESULTS: We found evidence of differential global methylation between treatment response groups. Further, we found patterns of cell-specific differential global methylation associated with MTX response. After correction for multiple testing, 1 differentially methylated position was associated with differential DNAm between responders and nonresponders at baseline in CD4+ T cells, CD8+ T cells, and natural killer cells. Thirty-nine cell-specific differentially methylated regions associated with MTX treatment response were identified. There were no significant findings in analyses of whole blood samples. CONCLUSION: We identified cell-specific changes in DNAm that were associated with MTX treatment response in RA patients. Future studies of DNAm and MTX treatment response should include measurements of DNAm from sorted cells.

Attitudes and practices in the laboratory monitoring of conventional synthetic disease modifying anti-rheumatic drugs by rheumatologists and rheumatology trainees.

OBJECTIVES: There is scant research about laboratory monitoring in people taking conventional synthetic disease-modifying anti-rheumatic drugs (csDMARDs) for rheumatic disease. Our objective was to conduct a scoping study to assess the range of current attitudes and the variation in practice of laboratory monitoring of csDMARDs by rheumatologists and trainees. METHODS: Australian and overseas rheumatologists or trainees were invited through newsletter, Twitter and personal e-mail, to complete an anonymous online survey between 1 February and 22 March 2021. Questions focused on laboratory tests requested by csDMARD prescribed, frequency/pattern of monitoring, influence of additional factors and combination therapy, actions in response to abnormal tests, and attitudes to monitoring frequencies. Results were presented descriptively and analysed using linear and logistic regression. RESULTS: There were 221 valid responses. Most respondents were from Australia (n = 53, 35%) followed by the US (n = 39, 26%), with a slight preponderance of women (n = 84, 56%), ≥ 11 years in rheumatology practice (n = 83, 56%) and in mostly public practice (n = 79, 53%). Respondents had a wide variation in the frequency and scheduling of tests. In general, respondents reported increasing monitoring frequency if patients had numerous comorbidities or if both methotrexate and leflunomide were being taken concurrently. There was a wide variety of responses to abnormal monitoring results and 27 (40%) considered that in general, monitoring tests are performed too frequently. CONCLUSIONS: The results demonstrated a wide variation in the frequency of testing, factors that should influence this, and what responses to abnormal test results are appropriate, indicates a likely lack of evidence and the need to define the risks, benefits and costs of different csDMARD monitoring regimens.

Engineered AAVs for non-invasive gene delivery to rodent and non-human primate nervous systems.

Gene therapy offers great promise in addressing neuropathologies associated with the central and peripheral nervous systems (CNS and PNS). However, genetic access remains difficult, reflecting the critical need for the development of effective and non-invasive gene delivery vectors across species. To that end, we evolved adeno-associated virus serotype 9 (AAV9) capsid in mice and validated two capsids, AAV-MaCPNS1 and AAV-MaCPNS2, across rodent species (mice and rats) and non-human primate (NHP) species (marmosets and rhesus macaques). Intravenous administration of either AAV efficiently transduced the PNS in rodents and both the PNS and CNS in NHPs. Furthermore, we used AAV-MaCPNS1 in mice to systemically deliver the following: (1) the neuronal sensor jGCaMP8s to record calcium signal dynamics in nodose ganglia and (2) the neuronal actuator DREADD to dorsal root ganglia to mediate pain. This conclusively demonstrates the translatability of these two systemic AAVs across four species and their functional utility through proof-of-concept studies in mice.

Development and Implementation of Dried Blood Spot-Based COVID-19 Serological Assays for Epidemiologic Studies.

Serological surveillance studies of infectious diseases provide population-level estimates of infection and antibody prevalence, generating crucial insight into population-level immunity, risk factors leading to infection, and effectiveness of public health measures. These studies traditionally rely on detection of pathogen-specific antibodies in samples derived from venipuncture, an expensive and logistically challenging aspect of serological surveillance. During the COVID-19 pandemic, guidelines implemented to prevent the spread of SARS-CoV-2 infection made collection of venous blood logistically difficult at a time when SARS-CoV-2 serosurveillance was urgently needed. Dried blood spots (DBS) have generated interest as an alternative to venous blood for SARS-CoV-2 serological applications due to their stability, low cost, and ease of collection; DBS samples can be self-generated via fingerprick by community members and mailed at ambient temperatures. Here, we detail the development of four DBS-based SARS-CoV-2 serological methods and demonstrate their implementation in a large serological survey of community members from 12 cities in the East Bay region of the San Francisco metropolitan area using at-home DBS collection. We find that DBS perform similarly to plasma/serum in enzyme-linked immunosorbent assays and commercial SARS-CoV-2 serological assays. In addition, we show that DBS samples can reliably detect antibody responses months postinfection and track antibody kinetics after vaccination. Implementation of DBS enabled collection of valuable serological data from our study population to investigate changes in seroprevalence over an 8-month period. Our work makes a strong argument for the implementation of DBS in serological studies, not just for SARS-CoV-2, but any situation where phlebotomy is inaccessible. IMPORTANCE Estimation of community-level antibody responses to SARS-CoV-2 from infection or vaccination is critical to inform public health responses. Traditional studies of antibodies rely on collection of blood via venipuncture, an invasive procedure not amenable to pandemic-related social-distancing measures. Dried blood spots (DBS) are an alternative to venipuncture, since they can be self-collected by study participants at home and do not require refrigeration for shipment or storage. However, DBS-based assays to measure antibody levels to SARS-CoV-2 have not been widely utilized. Here, we show that DBS are comparable to blood as a sampling method for antibody responses to SARS-CoV-2 infection and vaccination over time measured using four distinct serological assays. The DBS format enabled antibody surveillance in a longitudinal cohort where study participants self-collected samples, ensuring the participants' safety during an ongoing pandemic. Our work demonstrates that DBS are an excellent sampling method for measuring antibody responses whenever venipuncture is impractical.

Surgical method to prevent early death of neonatal rat pups with Hirschsprung disease, thus permitting development of long-term therapeutic approaches.

Hirschsprung disease occurs when children are born with no intrinsic nerve cells in varying lengths of the large intestine. In the most severe cases, neurons are also missing from the distal part of the small intestine. Nerve-mediated relaxation of the aganglionic bowel fails and fecal matter accumulates in the more proximal regions of the intestine. This is life threatening. Perforation of the bowel can ensue, causing sepsis and in some cases, death of the infant. Repopulation of the colon with neural stem cells is a potential therapy, but for this to be successful the patient or experimental animal needs to survive long enough for neural precursors to differentiate and make appropriate connections. We have developed a surgical procedure that can be applied to rats with Hirschsprung disease. A stoma was created to allow the normal bowel to empty and a second stoma leading to the aganglionic bowel was also created. This allowed homozygous mutants that would usually die at less than 3 weeks of age to survive into adulthood. During this time, the rats also required post-operative care of their stomas. The interventions we describe provide an animal model of Hirschsprung disease that is suited to assess the effectiveness of cell therapies in the treatment of this condition.

Feasibility of delivering and evaluating stratified care integrated with telehealth ('Rapid Stratified Telehealth') for patients with low back pain: protocol for a feasibility and pilot randomised controlled trial.

INTRODUCTION: Long waiting time is an important barrier to accessing recommended care for low back pain (LBP) in Australia's public health system. This study describes the protocol for a randomised controlled trial (RCT) that aims to establish the feasibility of delivering and evaluating stratified care integrated with telehealth ('Rapid Stratified Telehealth'), which aims to reduce waiting times for LBP. METHODS AND ANALYSIS: We will conduct a single-centre feasibility and pilot RCT with nested qualitative interviews. Sixty participants with LBP newly referred to a hospital outpatient clinic will be randomised to receive Rapid Stratified Telehealth or usual care. Rapid Stratified Telehealth involves matching the mode and type of care to participants' risk of persistent disabling pain (using the Keele STarT MSK Tool) and presence of potential radiculopathy. 'Low risk' patients are matched to one session of advice over the telephone, 'medium risk' to telehealth physiotherapy plus App-based exercises, 'high risk' to telehealth physiotherapy, App-based exercises, and an online pain education programme, and 'potential radiculopathy' fast tracked to usual in-person care. Primary outcomes include the feasibility of delivering Rapid Stratified Telehealth (ie, acceptability assessed through interviews with clinicians and patients, intervention fidelity, appointment duration, App useability and online pain education programme usage) and evaluating Rapid Stratified Telehealth in a future trial (ie, recruitment rates, consent rates, lost to follow-up and missing data). Secondary outcomes include waiting times, number of appointments, intervention and healthcare costs, clinical outcomes (pain, function, quality of life, satisfaction), healthcare use and adverse events (AEs). Quantitative analyses will be descriptive and inform a future adequately-powered RCT. Interview data will be analysed using thematic analysis. ETHICS AND DISSEMINATION: This study has received approval from the Ethics Review Committee (RPAH Zone: X21-0221). Results will be published in peer-reviewed journals and presented at conferences. TRIAL REGISTRATION NUMBER: ACTRN12621001104842.

Gene-environment interactions increase the risk of pediatric-onset multiple sclerosis associated with ozone pollution.

BACKGROUND: We previously reported a relationship between air pollutants and increased risk of pediatric-onset multiple sclerosis (POMS). Ozone is an air pollutant that may play a role in multiple sclerosis (MS) pathoetiology. CD86 is the only non-HLA gene associated with POMS for which expression on antigen-presenting cells (APCs) is changed in response to ozone exposure. OBJECTIVES: To examine the association between county-level ozone and POMS, and the interactions between ozone pollution, CD86, and HLA-DRB1*15, the strongest genetic variant associated with POMS. METHODS: Cases and controls were enrolled in the Environmental and Genetic Risk Factors for Pediatric MS study of the US Network of Pediatric MS Centers. County-level-modeled ozone data were acquired from the CDC's Environmental Tracking Network. Participants were assigned ozone values based on county of residence. Values were categorized into tertiles based on healthy controls. The association between ozone tertiles and having MS was assessed by logistic regression. Interactions between tertiles of ozone level and the GG genotype of the rs928264 (G/A) single nucleotide polymorphism (SNP) within CD86, and the presence of DRB1*15:01 (DRB1*15) on odds of POMS were evaluated. Models were adjusted for age, sex, genetic ancestry, and mother's education. Additive interaction was estimated using relative excess risk due to interaction (RERI) and attributable proportions (APs) of disease were calculated. RESULTS: A total of 334 POMS cases and 565 controls contributed to the analyses. County-level ozone was associated with increased odds of POMS (odds ratio 2.47, 95% confidence interval (CI): 1.69-3.59 and 1.95, 95% CI: 1.32-2.88 for the upper two tertiles, respectively, compared with the lowest tertile). There was a significant additive interaction between high ozone tertiles and presence of DRB1*15, with a RERI of 2.21 (95% CI: 0.83-3.59) and an AP of 0.56 (95% CI: 0.33-0.79). Additive interaction between high ozone tertiles and the CD86 GG genotype was present, with a RERI of 1.60 (95% CI: 0.14-3.06) and an AP of 0.37 (95% CI: 0.001-0.75) compared to the lowest ozone tertile. AP results indicated that approximately half of the POMS risk in subjects can be attributed to the possible interaction between higher county-level ozone carrying either DRB1*15 or the CD86 GG genotype. CONCLUSIONS: In addition to the association between high county-level ozone and POMS, we report evidence for additive interactions between higher county-level ozone and DRB1*15 and the CD86 GG genotype. Identifying gene-environment interactions may provide mechanistic insight of biological processes at play in MS susceptibility. Our work suggests a possible role of APCs for county-level ozone-induced POMS risk.

Health inequities in SARS-CoV-2 infection, seroprevalence, and COVID-19 vaccination: Results from the East Bay COVID-19 study.

Comprehensive data on transmission mitigation behaviors and both SARS-CoV-2 infection and serostatus are needed from large, community-based cohorts to identify COVID-19 risk factors and the impact of public health measures. We conducted a longitudinal, population-based study in the East Bay Area of Northern California. From July 2020-March 2021, approximately 5,500 adults were recruited and followed over three data collection rounds to investigate the association between geographic and demographic characteristics and transmission mitigation behavior with SARS-CoV-2 prevalence. We estimated the populated-adjusted prevalence of antibodies from SARS-CoV-2 infection and COVID-19 vaccination, and self-reported COVID-19 test positivity. Population-adjusted SARS-CoV-2 seroprevalence was low, increasing from 1.03% (95% CI: 0.50-1.96) in Round 1 (July-September 2020), to 1.37% (95% CI: 0.75-2.39) in Round 2 (October-December 2020), to 2.18% (95% CI: 1.48-3.17) in Round 3 (February-March 2021). Population-adjusted seroprevalence of COVID-19 vaccination was 21.64% (95% CI: 19.20-24.34) in Round 3, with White individuals having 4.35% (95% CI: 0.35-8.32) higher COVID-19 vaccine seroprevalence than individuals identifying as African American or Black, American Indian or Alaskan Native, Asian, Hispanic, two or more races, or other. No evidence for an association between transmission mitigation behavior and seroprevalence was observed. Despite >99% of participants reporting wearing masks individuals identifying as African American or Black, American Indian or Alaskan Native, Asian, Hispanic, two or more races, or other, as well as those in lower-income households, and lower-educated individuals had the highest SARS-CoV-2 seroprevalence and lowest vaccination seroprevalence. Results demonstrate that more effective policies are needed to address these disparities and inequities.

Novel Assay to Measure Seroprevalence of Zika Virus in the Philippines.

Zika virus (ZIKV) is a member of the Flaviviridae family, which includes other clinically notable viruses such as the 4 dengue virus serotypes (DENV-1-4). Distinguishing DENVs from ZIKV using the established serologic assays widely used for monitoring DENV transmission is difficult because of antibody cross-reactivity between these closely related flaviviruses. We describe a modified and improved recombinant envelope domain III-based serologic assay for detecting ZIKV type-specific antibodies in regions with endemic DENV transmission. When the assay was used to measure ZIKV seroprevalence in 2017 among children 9-14 years of age living in a region of the Philippines with endemic DENV transmission, we observed a ZIKV seroprevalence of 18%. Investigators should consider using the ZIKV envelope domain III-based assay, which is simple and readily adaptable for use in standard clinical and public health laboratories, to assess ZIKV seroprevalence in areas with endemic DENV transmission.

Dengue vaccine breakthrough infections reveal properties of neutralizing antibodies linked to protection.

The 4 serotypes of dengue virus (DENV1-4) are mosquito-borne flaviviruses that infect humans. Live attenuated tetravalent DENV vaccines are at different phases of clinical testing. DENV vaccine developers have relied on neutralizing antibodies (NAbs) as a correlate of protection. A leading tetravalent vaccine (Dengvaxia) stimulated NAbs to the 4 DENV serotypes, yet overall vaccine efficacy was low in children who were DENV seronegative at baseline before vaccination. We compared the properties of (a) NAbs induced by WT DENV1 or DENV3 infections, which are strongly correlated with protection from repeat infections, and (b) NAbs induced by Dengvaxia in individuals who subsequently experienced DENV1 or DENV3 breakthrough infections. WT infections induced NAbs that recognized epitopes unique (type specific) to each serotype, whereas the vaccine stimulated qualitatively different NAbs that recognized epitopes conserved (crossreactive) between serotypes. Our results indicate that, among children who were DENV-seronegative at baseline, unbalanced replication of the DENV type 4 vaccine component in the tetravalent vaccine stimulates Abs capable of crossneutralizing DENV1 and DENV3 in vitro, but not protecting in vivo. In DENV-seronegative individuals who are vaccinated, we propose that type-specific NAbs are a better correlate of protection than total levels of NAbs.

Endorsement of the domains of knee and hip osteoarthritis (OA) flare: A report from the OMERACT 2020 inaugural virtual consensus vote from the flares in OA working group.

OBJECTIVE: Towards developing an instrument to measure knee and hip osteoarthritis (KHOA) flare, the Outcome Measures in Rheumatology (OMERACT) Flares in OA Working Group first sought to identify and define relevant domains of flare in KHOA. METHODS: Guided by OMERACT Filter 2.1, candidate domains were identified from data generated in interviews, in English or French, with persons with KHOA and health professionals (HPs) who treat OA. The first and second rounds of an online Delphi process with patients and HPs, including researchers, selected relevant domains. The third round provided agreement on the selected domains and their definitions. At the virtual OMERACT 2020 workshop, the proposed domains and their definitions were discussed in facilitated breakout groups with patients and HPs. Participants then voted, with consensus set at ≥70%. RESULTS: Qualitative interviews characterizing OA flare were completed with 29 persons with KHOA and 16 HPs. Content was analyzed and grouped into nine clusters. These candidate domains were included in two Delphi rounds, completed by 91 patients and 165 HPs then 50 patients and 116 HPs, per round, respectively. This resulted in selecting five relevant domains. A final Delphi round, completed by 38 patients and 89 HPs, provided agreement on these domains and their definitions. The OMERACT virtual vote included 27 patients and 106 HPs. The domains and their definitions were endorsed with ≥98% agreement. Domains include: Pain, Swelling, Stiffness, Psychological aspects, and Impact of symptoms, all defined "during flare". CONCLUSION: Using OMERACT methodology, we have developed five domains of KHOA flare that were highly endorsed by patients and HPs.