Reduced SARS-CoV-2 mRNA vaccine immunogenicity and protection in mice with diet-induced obesity and insulin resistance

BACKGROUND

Obesity and type 2 diabetes mellitus (T2DM) are associated with an increased risk of severe outcomes from infectious diseases, including coronavirus disease 2019. These conditions are also associated with distinct responses to immunization, including an impaired response to widely used severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) mRNA vaccines.

OBJECTIVE

We sought to establish a connection between reduced immunization efficacy via modeling the effects of metabolic diseases on vaccine immunogenicity that is essential for the development of more effective vaccines for this distinct vulnerable population.

METHODS

A murine model of diet-induced obesity and insulin resistance was used to model the effects of comorbid T2DM and obesity on vaccine immunogenicity and protection.

RESULTS

Mice fed a high-fat diet (HFD) developed obesity, hyperinsulinemia, and glucose intolerance. Relative to mice fed a normal diet, HFD mice vaccinated with a SARS-CoV-2 mRNA vaccine exhibited significantly lower anti-spike IgG titers, predominantly in the IgG2c subclass, associated with a lower type 1 response, along with a 3.83-fold decrease in neutralizing titers. Furthermore, enhanced vaccine-induced spike-specific CD8+ T-cell activation and protection from lung infection against SARS-CoV-2 challenge were seen only in mice fed a normal diet but not in HFD mice.

CONCLUSIONS

The study demonstrated impaired immunity following SARS-CoV-2 mRNA immunization in a murine model of comorbid T2DM and obesity, supporting the need for further research into the basis for impaired anti-SARS-CoV-2 immunity in T2DM and investigation of novel approaches to enhance vaccine immunogenicity among those with metabolic diseases.

Precision Vaccinology Approaches for the Development of Adjuvanted Vaccines Targeted to Distinct Vulnerable Populations

Infection persists as one of the leading global causes of morbidity and mortality, with particular burden at the extremes of age and in populations who are immunocompromised or suffer chronic co-morbid diseases. By focusing discovery and innovation efforts to better understand the phenotypic and mechanistic differences in the immune systems of diverse vulnerable populations, emerging research in precision vaccine discovery and development has explored how to optimize immunizations across the lifespan. Here, we focus on two key elements of precision vaccinology, as applied to epidemic/pandemic response and preparedness, including (a) selecting robust combinations of adjuvants and antigens, and (b) coupling these platforms with appropriate formulation systems. In this context, several considerations exist, including the intended goals of immunization (e.g., achieving immunogenicity versus lessening transmission), reducing the likelihood of adverse reactogenicity, and optimizing the route of administration. Each of these considerations is accompanied by several key challenges. On-going innovation in precision vaccinology will expand and target the arsenal of vaccine components for protection of vulnerable populations.

Carbohydrate fatty acid monosulphate: oil-in-water adjuvant enhances SARS-CoV-2 RBD nanoparticle-induced immunogenicity and protection in mice

Development of SARS-CoV-2 vaccines that protect vulnerable populations is a public health priority. Here, we took a systematic and iterative approach by testing several adjuvants and SARS-CoV-2 antigens to identify a combination that elicits antibodies and protection in young and aged mice. While demonstrating superior immunogenicity to soluble receptor-binding domain (RBD), RBD displayed as a protein nanoparticle (RBD-NP) generated limited antibody responses. Comparison of multiple adjuvants including AddaVax, AddaS03, and AS01B in young and aged mice demonstrated that an oil-in-water emulsion containing carbohydrate fatty acid monosulphate derivative (CMS:O/W) most effectively enhanced RBD-NP-induced cross-neutralizing antibodies and protection across age groups. CMS:O/W enhanced antigen retention in the draining lymph node, induced injection site, and lymph node cytokines, with CMS inducing MyD88-dependent Th1 cytokine polarization. Furthermore, CMS and O/W synergistically induced chemokine production from human PBMCs. Overall, CMS:O/W adjuvant may enhance immunogenicity and protection of vulnerable populations against SARS-CoV-2 and other infectious pathogens.

The mRNA vaccine BNT162b2 demonstrates impaired TH1 immunogenicity in human elders in vitro and aged mice in vivo

mRNA vaccines have been key to addressing the SARS-CoV-2 pandemic but have impaired immunogenicity and durability in vulnerable older populations. We evaluated the mRNA vaccine BNT162b2 in human in vitro whole blood assays with supernatants from adult (18-50 years) and elder (≥60 years) participants measured by mass spectrometry and proximity extension assay proteomics. BNT162b2 induced increased expression of soluble proteins in adult blood (e.g., C1S, PSMC6, CPN1), but demonstrated reduced proteins in elder blood (e.g., TPM4, APOF, APOC2, CPN1, and PI16), including 30-85% lower induction of TH1-polarizing cytokines and chemokines (e.g., IFNγ, and CXCL10). Elder TH1 impairment was validated in mice in vivo and associated with impaired humoral and cellular immunogenicity. Our study demonstrates the utility of a human in vitro platform to model age-specific mRNA vaccine activity, highlights impaired TH1 immunogenicity in older adults, and provides rationale for developing enhanced mRNA vaccines with greater immunogenicity in vulnerable populations.

Reduced SARS-CoV-2 mRNA vaccine immunogenicity and protection in mice with diet-induced obesity and insulin resistance

Background

Obesity and Type 2 Diabetes Mellitus (T2DM) are associated with an increased risk of severe outcomes from infectious diseases, including COVID-19. These conditions are also associated with distinct responses to immunization, including an impaired response to widely used SARS-CoV-2 mRNA vaccines.

Objective

To establish a connection between reduced immunization efficacy via modeling the effects of metabolic diseases on vaccine immunogenicity that is essential for the development of more effective vaccines for this distinct vulnerable population.

Methods

We utilized a murine model of diet-induced obesity and insulin resistance to model the effects of comorbid T2DM and obesity on vaccine immunogenicity and protection.

Results

Mice fed a high-fat diet (HFD) developed obesity, hyperinsulinemia, and glucose intolerance. Relative to mice fed a normal diet (ND), HFD mice vaccinated with a SARS-CoV-2 mRNA vaccine exhibited significantly lower anti-spike IgG titers, predominantly in the IgG2c subclass, associated with a lower type 1 response, along with a 3.83-fold decrease in neutralizing titers. Furthermore, enhanced vaccine-induced spike-specific CD8 + T cell activation and protection from lung infection against SARS-CoV-2 challenge were seen only in ND mice but not in HFD mice.

Conclusion

We demonstrate impaired immunity following SARS-CoV-2 mRNA immunization in a murine model of comorbid T2DM and obesity, supporting the need for further research into the basis for impaired anti-SARS-CoV-2 immunity in T2DM and investigation of novel approaches to enhance vaccine immunogenicity among those with metabolic diseases.

Capsule summary

Obesity and type 2 diabetes impair SARS-CoV-2 mRNA vaccine efficacy in a murine model.

Waning effectiveness of SARS-CoV-2 mRNA vaccines in older adults: a rapid review

The U.S. Centers for Disease Control and Prevention (CDC) and other health agencies have recently recommended a booster dose of COVID-19 vaccines for specific vulnerable groups including adults 65 years and older. There is limited evidence whether vaccine effectiveness (VE) in older adults decreases over time, especially against severe COVID-19. We performed a rapid review of published studies available through 4 November 2021 that provide effectiveness data on messenger RNA (mRNA) vaccines approved/licensed in the United States and identified eight eligible studies which evaluated VE in older adults. There is evidence of a decline in VE against both severe acute respiratory syndrome coronavirus 2 infection and severe COVID-19 in older adults among studies which analyzed data up to July-October 2021. Our findings suggest that VE diminishes in older adults, which supports the current recommendation for a booster dose in this population.

Shaping Neonatal Immunization by Tuning the Delivery of Synergistic Adjuvants via Nanocarriers

Adjuvanted nanocarrier-based vaccines hold substantial potential for applications in novel early-life immunization strategies. Here, via mouse and human age-specific in vitro modeling, we identified the combination of a small-molecule STING agonist (2'3'-cyclic GMP-AMP, cGAMP) and a TLR7/8 agonist (CL075) to drive the synergistic activation of neonatal dendritic cells and precision CD4 T-helper (Th) cell expansion via the IL-12/IFNγ axis. We further demonstrate that the vaccination of neonatal mice with quadrivalent influenza recombinant hemagglutinin (rHA) and an admixture of two polymersome (PS) nanocarriers separately encapsulating cGAMP (cGAMP-PS) and CL075 (CL075-PS) drove robust Th1 bias, high frequency of T follicular helper (T_FH) cells, and germinal center (GC) B cells along with the IgG2c-skewed humoral response in vivo. Dual-loaded cGAMP/CL075-PSs did not outperform admixed cGAMP-PS and CL075-PS in vivo. These data validate an optimally designed adjuvantation system via age-selected small-molecule synergy and a multicomponent nanocarrier formulation as an effective approach to induce type 1 immune responses in early life.

mRNA booster vaccination protects aged mice against the SARS-CoV-2 Omicron variant

The SARS-CoV-2 Omicron variant evades vaccine-induced immunity. While a booster dose of ancestral mRNA vaccines effectively elicits neutralizing antibodies against variants, its efficacy against Omicron in older adults, who are at the greatest risk of severe disease, is not fully elucidated. Here, we evaluate multiple longitudinal immunization regimens of mRNA BNT162b2 to assess the effects of a booster dose provided >8 months after the primary immunization series across the murine lifespan, including in aged 21-month-old mice. Boosting dramatically enhances humoral and cell-mediated responses with evidence of Omicron cross-recognition. Furthermore, while younger mice are protected without a booster dose, boosting provides sterilizing immunity against Omicron-induced lung infection in aged 21-month-old mice. Correlational analyses reveal that neutralizing activity against Omicron is strongly associated with protection. Overall, our findings indicate age-dependent vaccine efficacy and demonstrate the potential benefit of mRNA booster immunization to protect vulnerable older populations against SARS-CoV-2 variants.

A longitudinal study in mice reveals that a booster dose of mRNA vaccine BNT162b2 enhances humoral and cell-mediated responses and provides sterilizing immunity against Omicron-induced lung infection in aged animals.

Adjuvant Discovery via a High Throughput Screen using Human Primary Mononuclear Cells

Motivation

Vaccines are a key biomedical intervention to prevent the spread of infectious diseases, but their efficacy can be limited by insufficient immunogenicity and nonuniform reactogenic profiles. Adjuvants are molecules that potentiate vaccine responses by inducing innate immune activation. However, there are a limited number of adjuvants in approved vaccines, and current approaches for preclinical adjuvant discovery and development are inefficient. To enhance adjuvant identification, we developed a protocol based on in vitro screening of human primary leukocytes.

Summary

We describe a methodology utilizing high-throughput and high-content screening for novel adjuvant candidates that was used to screen a library of ~2,500 small molecules via a 384-well quantitative combined cytokine and flow cytometry immunoassay in primary human peripheral blood mononuclear cells (PBMCs) from 4 healthy adult study participants. Hits were identified based on their induction of soluble cytokine (TNF, IFNg and IL-10) secretion and PBMC maturation (CD 80/86, Ox40, and HLA-DR) in at least two of the four donors screened. From an initial set of 197 compounds identified using these biomarkers-an 8.6% hit rate-we downselected to five scaffolds that demonstrated robust efficacy and potency in vitro and evaluated the top hit, vinblastine sulfate, for adjuvanticity in vivo. Vinblastine sulfate significantly enhanced murine humoral responses to recombinant SARS-CoV-2 spike protein, including a four-fold enhancement of IgG titer production when compared to treatment with the spike antigen alone. Overall, we outline a methodology for discovering immunomodulators with adjuvant potential via high-throughput screening of PBMCs in vitro that yielded a lead compound with in vivo adjuvanticity.

Precision Vaccine Adjuvants for Older Adults: A Scoping Review

Older adults, defined as those ≥60 years of age, are a growing population vulnerable to infections including severe acute respiratory syndrome coronavirus 2. Although immunization is a key to protecting this population, immunosenescence can impair responses to vaccines. Adjuvants can increase the immunogenicity of vaccine antigens but have not been systematically compared in older adults. We conducted a scoping review to assess the comparative effectiveness of adjuvants in aged populations. Adjuvants AS01, MF59, AS03, and CpG-oligodeoxynucleotide, included in licensed vaccines, are effective in older human adults. A growing menu of investigational adjuvants, such as Matrix-M and CpG plus alum, showed promising results in early phase clinical trials and preclinical studies. Most studies assessed only 1 or 2 adjuvants and no study has directly compared >3 adjuvants among older adults. Enhanced preclinical approaches enabling direct comparison of multiple adjuvants including human in vitro modeling and age-specific animal models may derisk and accelerate vaccine development for older adults.

Precision Vaccine Development: Cues From Natural Immunity

Traditional vaccine development against infectious diseases has been guided by the overarching aim to generate efficacious vaccines normally indicated by an antibody and/or cellular response that correlates with protection. However, this approach has been shown to be only a partially effective measure, since vaccine- and pathogen-specific immunity may not perfectly overlap. Thus, some vaccine development strategies, normally focused on targeted generation of both antigen specific antibody and T cell responses, resulting in a long-lived heterogenous and stable pool of memory lymphocytes, may benefit from better mimicking the immune response of a natural infection. However, challenges to achieving this goal remain unattended, due to gaps in our understanding of human immunity and full elucidation of infectious pathogenesis. In this review, we describe recent advances in the development of effective vaccines, focusing on how understanding the differences in the immunizing and non-immunizing immune responses to natural infections and corresponding shifts in immune ontogeny are crucial to inform the next generation of infectious disease vaccines.

An adjuvant strategy enabled by modulation of the physical properties of microbial ligands expands antigen immunogenicity

Activation of the innate immune system via pattern recognition receptors (PRRs) is key to generate lasting adaptive immunity. PRRs detect unique chemical patterns associated with invading microorganisms, but whether and how the physical properties of PRR ligands influence the development of the immune response remains unknown. Through the study of fungal mannans, we show that the physical form of PRR ligands dictates the immune response. Soluble mannans are immunosilent in the periphery but elicit a potent pro-inflammatory response in the draining lymph node (dLN). By modulating the physical form of mannans, we developed a formulation that targets both the periphery and the dLN. When combined with viral glycoprotein antigens, this mannan formulation broadens epitope recognition, elicits potent antigen-specific neutralizing antibodies, and confers protection against viral infections of the lung. Thus, the physical properties of microbial ligands determine the outcome of the immune response and can be harnessed for vaccine development.

An aluminum hydroxide:CpG adjuvant enhances protection elicited by a SARS-CoV-2 receptor binding domain vaccine in aged mice

Global deployment of vaccines that can provide protection across several age groups is still urgently needed to end the COVID-19 pandemic, especially in low- and middle-income countries. Although vaccines against SARS-CoV-2 based on mRNA and adenoviral vector technologies have been rapidly developed, additional practical and scalable SARS-CoV-2 vaccines are required to meet global demand. Protein subunit vaccines formulated with appropriate adjuvants represent an approach to address this urgent need. The receptor binding domain (RBD) is a key target of SARS-CoV-2 neutralizing antibodies but is poorly immunogenic. We therefore compared pattern recognition receptor (PRR) agonists alone or formulated with aluminum hydroxide (AH) and benchmarked them against AS01B and AS03-like emulsion-based adjuvants for their potential to enhance RBD immunogenicity in young and aged mice. We found that an AH and CpG adjuvant formulation (AH:CpG) produced an 80-fold increase in anti-RBD neutralizing antibody titers in both age groups relative to AH alone and protected aged mice from the SARS-CoV-2 challenge. The AH:CpG-adjuvanted RBD vaccine elicited neutralizing antibodies against both wild-type SARS-CoV-2 and the B.1.351 (beta) variant at serum concentrations comparable to those induced by the licensed Pfizer-BioNTech BNT162b2 mRNA vaccine. AH:CpG induced similar cytokine and chemokine gene enrichment patterns in the draining lymph nodes of both young adult and aged mice and enhanced cytokine and chemokine production in human mononuclear cells of younger and older adults. These data support further development of AH:CpG-adjuvanted RBD as an affordable vaccine that may be effective across multiple age groups.

The immunoregulatory function of peripheral blood CD71+ erythroid cells in systemic-onset juvenile idiopathic arthritis

CD71⁺ erythroid cells (CECs) are recognized to have an immunoregulatory function via direct cell–cell interaction and soluble mediators. Circulating CECs appear in newborns or patients with hemolytic and cardiopulmonary disorders. To assess the biological role of CECs in systemic inflammation, we studied the gene expression and function in systemic-onset juvenile idiopathic arthritis (SoJIA). Peripheral blood mononuclear cells of SoJIA patients expressed upregulated erythropoiesis-related genes. It represented the largest expansion of CECs during active phase SoJIA among other inflammatory diseases. Despite the opposing roles of erythropoietin and hepcidin in erythropoiesis, both serum levels were in concert with the amounts of SoJIA-driven CECs. Circulating CECs counts in inflammatory diseases were positively correlated with the levels of C-reactive protein, IL-6, IL-18, or soluble TNF receptors. Co-culture with active SoJIA-driven CECs suppressed secretions of IL-1β, IL-6, and IL-8 from healthy donor monocytes. The top upregulated gene in SoJIA-driven CECs was ARG2 compared with CECs from cord blood controls, although cytokine production from monocytes was suppressed by co-culture, even with an arginase inhibitor. CECs are driven to the periphery during the acute phase of SoJIA at higher levels than other inflammatory diseases. Circulating CECs may control excessive inflammation via the immunoregulatory pathways, partly involving arginase-2.

Alum:CpG adjuvant enables SARS-CoV-2 RBD-induced protection in aged mice and synergistic activation of human elder type 1 immunity

Global deployment of vaccines that can provide protection across several age groups is still urgently needed to end the COVID-19 pandemic especially for low- and middle-income countries. While vaccines against SARS-CoV-2 based on mRNA and adenoviral-vector technologies have been rapidly developed, additional practical and scalable SARS-CoV-2 vaccines are needed to meet global demand. In this context, protein subunit vaccines formulated with appropriate adjuvants represent a promising approach to address this urgent need. Receptor-binding domain (RBD) is a key target of neutralizing antibodies (Abs) but is poorly immunogenic. We therefore compared pattern recognition receptor (PRR) agonists, including those activating STING, TLR3, TLR4 and TLR9, alone or formulated with aluminum hydroxide (AH), and benchmarked them to AS01B and AS03-like emulsion-based adjuvants for their potential to enhance RBD immunogenicity in young and aged mice. We found that the AH and CpG adjuvant formulation (AH:CpG) demonstrated the highest enhancement of anti-RBD neutralizing Ab titers in both age groups (∼80-fold over AH), and protected aged mice from the SARS-CoV-2 challenge. Notably, AH:CpG-adjuvanted RBD vaccine elicited neutralizing Abs against both wild-type SARS-CoV-2 and B.1.351 variant at serum concentrations comparable to those induced by the authorized mRNA BNT162b2 vaccine. AH:CpG induced similar cytokine and chemokine gene enrichment patterns in the draining lymph nodes of both young adult and aged mice and synergistically enhanced cytokine and chemokine production in human young adult and elderly mononuclear cells. These data support further development of AH:CpG-adjuvanted RBD as an affordable vaccine that may be effective across multiple age groups.

One Sentence Summary

Alum and CpG enhance SARS-CoV-2 RBD protective immunity, variant neutralization in aged mice and Th1-polarizing cytokine production by human elder leukocytes.

An adjuvant strategy enabled by modulation of the physical properties of fungal mannans elicits pan-coronavirus reactive anti-SARS-CoV-2 Spike antibodies

Activation of the innate immune system via pattern recognition receptors (PRRs) is key to generate long-lasting adaptive immunity. While it is known that PRRs detect unique chemical patterns associated with invading microorganism, if and how the physical properties of PRR ligands influence development of the immune response is largely overlooked. Through the study of fungal mannans we present data that put the physical form of PRR ligands at the center of the process that determines the outcome of the immune response. Soluble mannans are immunosilent in the periphery but elicit a potent pro-inflammatory response in the draining lymph node (dLN). By modulating the physical form of mannans, we developed a formulation that targets both periphery and dLN. When combined with SARS-CoV-2 Spike, this formulation elicits neutralizing anti-SARS-CoV-2 antibodies that cross-react with pathogenic coronaviruses. Thus, the physical properties of fungal ligands can be harnessed for rational adjuvant design and vaccine development.

Detailed analysis of Japanese patients with adenosine deaminase 2 deficiency reveals characteristic elevation of type II interferon signature and STAT1 hyperactivation

BACKGROUND

Deficiency of adenosine deaminase 2 (DADA2) is an autosomal recessive inflammatory disease caused by loss-of-function mutations in both alleles of the ADA2 gene. Most patients with DADA2 exhibit systemic vasculopathy consistent with polyarteritis nodosa, but large phenotypic variability has been reported, and the pathogenesis of DADA2 remains unclear.

OBJECTIVES

This study sought to assess the clinical and genetic characteristics of Japanese patients with DADA2 and to gain insight into the pathogenesis of DADA2 by multi-omics analysis.

METHODS

Clinical and genetic data were collected from 8 Japanese patients with DADA2 diagnosed between 2016 and 2019. ADA2 variants in this cohort were functionally analyzed by in vitro overexpression analysis. PBMCs from 4 patients with DADA2 were subjected to transcriptome and proteome analyses. Patient samples were collected before and after introduction of anti- TNF-α therapies. Transcriptome data were compared with those of normal controls and patients with other autoinflammatory diseases.

RESULTS

Five novel ADA2 variants were identified in these 8 patients and were confirmed pathogenic by in vitro analysis. Anti-TNF-α therapy controlled inflammation in all 8 patients. Transcriptome and proteome analyses showed that upregulation of type II interferon signaling was characteristic of DADA2. Network analysis identified STAT1 as a key regulator and a hub molecule in DADA2 pathogenesis, a finding supported by the hyperactivation of STAT1 in patients' monocytes and B cells after IFN-γ stimulation.

CONCLUSIONS

Type II interferon signaling and STAT1 are associated with the pathogenesis of DADA2.

Overlapping Features in Kawasaki Disease-Related Arthritis and Systemic-Onset Juvenile Idiopathic Arthritis: A Nationwide Study in Japan

Background: Arthritis may occur after the diagnosis of Kawasaki disease (KD). Most cases are self-limiting; however, some patients require prolonged treatment. Method: To characterize KD-related arthritis, 14 patients who required arthritis treatment within 30 days after the diagnosis of KD were recruited from the 23rd KD survey in Japan. Twenty-six additional patients were included from our tertiary center and literature review cohorts. Results: The estimated prevalence of KD-related arthritis in Japan was 48 per 100,000 KD patients. Patients with KD-related arthritis had an older age at onset (52 vs. 28 months, P = 0.002) and higher rate of intravenous immunoglobulin (IVIG) resistance in comparison to those without arthritis (86 vs. 17%, P < 0.001). Among 40 patients, 18 had arthritis in the acute phase KD (continued fever-onset type) and 22 did in the convalescent phase (interval fever-onset type). Both showed a similar rate of complete KD or IVIG response. Interval-type patients required biologics for arthritis control less frequently (5 vs. 39%, P = 0.02) and had a higher 2-year off-treatment rate (100 vs. 43%, P = 0.009) than continued-type ones. Interval-types showed lower serum ferritin and interleukin-18 levels than continued-types. When continued-types were grouped according to whether or not they required biologics (n = 7 and n = 11, respectively), the former subgroup had higher ferritin and interleukin-18 levels (P = 0.01 and 0.02, respectively). A canonical discriminant analysis differentiated interval-type from continued-type with the combination of age, time to arthritis, and the ferritin and matrix metalloproteinase-3 levels. Conclusion: Arthritis requiring treatment is a rare complication of KD. KD-associated arthritis includes interval-type (KD-reactive) and continued-type (true systemic-onset juvenile idiopathic arthritis [JIA] requiring biologics), and overlapping arthritis, suggesting the pathophysiological continuity of autoinflammation between KD and JIA.

Delayed Development of Coronary Artery Aneurysm in Patients with Kawasaki Disease Who Were Clinically Responsive to Immunoglobulin

OBJECTIVE

To clarify the frequency and characteristics of discrepant outcomes of intravenous immunoglobulin (IVIG) between fever and coronary artery aneurysms (CAAs) in patients with Kawasaki disease.

STUDY DESIGN

This study included 325 patients who responded to oral aspirin and IVIG alone. The main outcome was CAA 4 weeks after disease onset. CAA was defined as ≥2.5 of maximum z score (Zmax) representing the highest value of 4 coronary artery branches. Immunoglobulin dosage and sequential changes in Zmax were reviewed to investigate the effects on fever and timing of CAA development. Logistic regression analyses with receiver operating characteristic curves using clinical and laboratory variables including the initial Zmax were performed to identify predictors of CAA at 4 weeks.

RESULTS

CAAs were either persistent or appeared de novo 4 weeks after diagnosis in 13 of 325 patients who responded to a single or repeated IVIG. Four single-dose IVIG-responders developed CAA although they had pretreatment Zmax of <2.0. The 2 single-dose IVIG responders with the greatest pretreatment Zmax (>4.5) developed persistent CAA. Receiver operating characteristic analysis demonstrated Zmax of 2.57 as the cut-off for predicting CAA. Multivariable analyses identified >2.5 Zmax (OR 9.08, 95% CI 1.26-65.3, P = .028, 50% sensitivity, 91% specificity) as the sole risk factor for CAA at 4 weeks in single-dose IVIG responders.

CONCLUSIONS

Delayed development and persistence of CAA in single-dose IVIG responders indicate that some factors other than those responsible for systemic inflammation may contribute to vasculitis in CAA. Baseline Zmax 2.5 aids in predicting CAAs.

Previous antibiotic use and the development of Kawasaki disease: a matched pair case-control study

BACKGROUND

Kawasaki disease (KD) is an acute febrile illness with systemic vasculitides, mostly affecting infants and young children. The etiology of KD is still unclear; however, altered gut microbiota have been recently implicated as a contributing factor for the development of vasculitis.

METHODS

We conducted an age- and gender-matched case-control study on 50 patients and 200 control subjects to search for potential factors leading to intestinal dysbiosis associated with KD. Data were analyzed using conditional multivariable logistic regression.

RESULTS

Previous antibiotic administration was associated with the patients who developed KD (odds ratio [OR] 11.7, 95% confidence interval [CI] 4.7-29.1, P < 0.0001), but not other variables, including breastfeeding and group nursery. In subgroup analyses, cesarean birth was indicated as an associated factor in addition to previous antibiotic administration in infants under 12 months of age (OR: 8.0, 95% CI: 1.8-34.4, P = 0.005), but not in older children.

CONCLUSIONS

The association between previous antibiotic administration and the onset of KD was demonstrated. Antibiotics may contribute to the development of KD by affecting the intestinal microbiota in infants and young children.

Toward precision adjuvants: optimizing science and safety

PURPOSE OF REVIEW

The gradual replacement of inactivated whole cell and live attenuated vaccines with subunit vaccines has generally reduced reactogenicity but in many cases also immunogenicity. Although only used when necessary, adjuvants can be key to vaccine dose/antigen-sparing, broadening immune responses to variable antigens, and enhancing immunogenicity in vulnerable populations with distinct immunity. Licensed vaccines contain an increasing variety of adjuvants, with a growing pipeline of adjuvanted vaccines under development.

RECENT FINDINGS

Most adjuvants, including Alum, Toll-like receptor agonists and oil-in-water emulsions, activate innate immunity thereby altering the quantity and quality of an adaptive immune response. Adjuvants activate leukocytes, and induce mediators (e.g., cytokines, chemokines, and prostaglandin-E2) some of which are biomarkers for reactogenicity, that is, induction of local/systemic side effects. Although there have been safety concerns regarding a hypothetical risk of adjuvants inducing auto-immunity, such associations have not been established. As immune responses vary by population (e.g., age and sex), adjuvant research now incorporates principles of precision medicine. Innovations in adjuvant research include use of human in vitro models, immuno-engineering, novel delivery systems, and systems biology to identify biomarkers of safety and adjuvanticity.

SUMMARY

Adjuvants enhance vaccine immunogenicity and can be associated with reactogenicity. Novel multidisciplinary approaches hold promise to accelerate and de-risk targeted adjuvant discovery and development. VIDEO ABSTRACT: http://links.lww.com/MOP/A53.

Clinical Utility of Highly Purified 10% Liquid Intravenous Immunoglobulin in Kawasaki Disease

Compared with a 5% intravenous immunoglobulin, a 10% intravenous immunoglobulin as the first-line treatment of Kawasaki disease significantly reduced the fever duration (10 vs 13 hours, P = .022) among the responders, and the interval to adjunctive therapy for nonresponders (47 vs 49 hours, P = .035). There were no severe adverse events.

A Nationwide Survey of Pediatric-onset Japanese Encephalitis in Japan

BACKGROUND

Japanese encephalitis (JE) is the leading cause of viral encephalitis with high mortality and morbidity in Asia. In Japan, however, the active recommendation of JE vaccine was retracted in 2005 because of the potential risk of acute disseminated encephalomyelitis. We aimed to determine the recent incidence of childhood-onset JE after the domestic change of vaccination policy in Japan, and to analyze the clinical features of affected children.

METHODS

A retrospective nationwide survey was conducted for pediatric patients with JE in Japan from 1995 to 2015. The national surveillance system was used to identify the pediatric patients with JE. Follow-up questionnaires were sent to analyze their clinical and neuroimaging profiles.

RESULTS

Among a total of 109 patients registered to the national surveillance, 10 (9%) were less than age 15 years. The annual incidence rate of childhood-onset JE was higher during 2005-15 than that during 1995-2004 (4.3 × 10-3 vs 1.1 × 10-3 per 100000, respectively; P = .04). Endemic regions overlapped with prefectures that farmed pigs harboring antibodies against JE virus with high prevalence. Detailed clinical data were collected from 9 patients. None of them died, but 5 of 9 patients (56%) had neurological sequelae after recovery. One patient who was partially vaccinated with 2 doses of JE vaccine fully recovered from a coma. The age of 3 years or less was associated with unfavorable neurological prognosis.

CONCLUSIONS

Our data provide evidence for the importance and prophylactic effect of the JE vaccine in young children in the endemic area.

Effective infliximab therapy for the early regression of coronary artery aneurysm in Kawasaki disease

BACKGROUND

There is limited information available regarding the role of infliximab (IFX) following the acute phase of Kawasaki disease (KD). We aimed to evaluate whether IFX is associated with coronary artery aneurysm (CAA) regression.

METHODS

Between 2005 and 2016, we identified 971 consecutive patients with KD from 3 tertiary institutions, and 49 (5%) with CAAs were enrolled in our study. Patients were divided into 2 groups: 27 who received IFX and 22 who did not. The persistence rate of CAAs was compared between the groups.

RESULTS

Age, sex, and duration of the febrile period did not significantly differ between the groups. The maximum value of C-reactive protein was higher in the IFX- than in the non-IFX group. The maximum z-score of CAAs did not differ between the groups. The 2-, 4- and 6-year cumulative persistence rate of CAA was 24%, 24% and 24% in IFX-group, whereas 67%, 52% and 33% in non-IFX group, respectively (P = 0.03). The median duration of CAA regression was 1.1 vs. 4.6 years. Among those who developed medium- or large-sized CAAs, the 2-, 4- and 6-year cumulative persistence rate of CAA was 33%, 33% and 33% in IFX group, whereas 77%, 51% and 48% in non-IFX group, respectively (P = 0.047). Multivariate logistic regression analysis indicated that the maximum z-score (hazard ratio 0.72, p < 0.001) and response to IFX (hazard ratio 4.56, p = 0.017) were independently related to regression.

CONCLUSION

IFX therapy was observed to be effective for the early improvement of CAAs in patients with intravenous immunoglobulin-resistant KD.

Clarithromycin Plus Intravenous Immunoglobulin Therapy Can Reduce the Relapse Rate of Kawasaki Disease: A Phase 2, Open-Label, Randomized Control Study

Background

We previously reported that biofilms and innate immunity contribute to the pathogenesis of Kawasaki disease. Therefore, we aimed to assess the efficacy of clarithromycin, an antibiofilm agent, in patients with Kawasaki disease.

Methods and Results

We conducted an open‐label, multicenter, randomized, phase 2 trial at 8 hospitals in Japan. Eligible patients included children aged between 4 months and 5 years who were enrolled between days 4 and 8 of illness. Participants were randomly allocated to receive either intravenous immunoglobulin (IVIG) or IVIG plus clarithromycin. The primary end point was the duration of fever after the initiation of IVIG treatment. Eighty‐one eligible patients were randomized. The duration of the fever did not differ between the 2 groups (mean±SD, 34.3±32.4 and 31.1±31.1 hours in the IVIG plus clarithromycin group and the IVIG group, respectively [P=0.66]). The relapse rate of patients in the IVIG plus clarithromycin group was significantly lower than that in the IVIG group (12.5% versus 30.8%, P=0.046). No serious adverse events occurred during the study period. In a post hoc analysis, the patients in the IVIG plus clarithromycin group required significantly shorter mean lengths of hospital stays than those in the IVIG group (8.9 days versus 10.3 days, P=0.049).

Conclusions

Although IVIG plus clarithromycin therapy failed to shorten the duration of fever, it reduced the relapse rate and shortened the duration of hospitalization in patients with Kawasaki disease.

Clinical Trial Registration

URL: http://www.umin.ac.jp/ctr/index.htm. Unique identifier: UMIN000015437.

Polymyxin-B immobilized column-direct hemoperfusion for adolescent toxic shock syndrome

Toxic shock syndrome (TSS) is a critical illness associated with toxin from Staphylococcus aureus. Despite recent advances in critical care, mortality remains high and additional effective therapy is required. We report an adolescent case of TSS successfully treated with direct hemoperfusion using polymyxin-B immobilized fiber (PMX-DHP). The patient with spina bifida also had ischial pressure ulcer, and developed TSS associated with methicillin-resistant S. aureus. Despite conventional treatment, the patient developed refractory shock, which was immediately improved with PMX-DHP. PMX-DHP has been widely used for the treatment of sepsis to remove circulating endotoxins produced by Gram-negative bacteria, but beneficial effects have also been reported for Gram-positive bacterial infection. To our knowledge, this is the first report on PMX-DHP for TSS in an adolescent patient, and we propose that PMX-DHP could be a new treatment strategy for severe TSS in children as well.

A nationwide survey of common viral infections in childhood among patients with primary immunodeficiency diseases

OBJECTIVES

Patients with primary immunodeficiency diseases (PID) are highly susceptible to various microorganisms. However, no population-based studies have been performed among common viral pathogens, such as respiratory syncytial virus (RSV), rotavirus (RV), varicella-zoster virus (VZV) and influenza virus (IV). The objective of this study was to reveal the clinical burden of these four infections among PID patients in Japan.

METHODS

We conducted a nationwide survey by sending questionnaires to 898 hospitals with pediatric departments throughout Japan.

RESULTS

Nine hundred ten PID patients from 621 hospitals were registered (response rate: 69.2%). Fifty-four of the patients were hospitalized due to these viral infections. The durations of hospitalization due to RSV and RV infections differed significantly in the PID patients with and without cellular immunodeficiency (12.0 vs 6.5 days, p = 0.041; and 14.0 vs 6.0 days, p = 0.031, respectively). There was no significant difference in the duration of hospitalization in PID patients with and without cellular immunodeficiency who were hospitalized with IV infections (7.3 vs 6.1 days, p = 0.53).

CONCLUSIONS

Special attention should be paid to PID patients with compromised cellular immunity who present with RSV and RV infection due to their high risk for severe disease.

Activation of Nod1 Signaling Induces Fetal Growth Restriction and Death through Fetal and Maternal Vasculopathy

Intrauterine fetal growth restriction (IUGR) and death (IUFD) are both serious problems in the perinatal medicine. Fetal vasculopathy is currently considered to account for a pathogenic mechanism of IUGR and IUFD. We previously demonstrated that an innate immune receptor, the nucleotide-binding oligomerization domain-1 (Nod1), contributed to the development of vascular inflammations in mice at postnatal stages. However, little is known about the deleterious effects of activated Nod1 signaling on embryonic growth and development. We report that administration of FK565, one of the Nod1 ligands, to pregnant C57BL/6 mice induced IUGR and IUFD. Mass spectrometry analysis revealed that maternally injected FK565 was distributed to the fetal tissues across placenta. In addition, maternal injection of FK565 induced robust increases in the amounts of CCL2, IL-6, and TNF proteins as well as NO in maternal, placental and fetal tissues. Nod1 was highly expressed in fetal vascular tissues, where significantly higher levels of CCL2 and IL-6 mRNAs were induced with maternal injection of FK565 than those in other tissues. Using Nod1-knockout mice, we verified that both maternal and fetal tissues were involved in the development of IUGR and IUFD. Furthermore, FK565 induced upregulation of genes associated with immune response, inflammation, and apoptosis in fetal vascular tissues. Our data thus provided new evidence for the pathogenic role of Nod1 in the development of IUGR and IUFD at the maternal-fetal interface.

Memory B-Cell Pools Predict the Immune Response to Pneumococcal Conjugate Vaccine in Immunocompromised Children

BACKGROUND

The immune responses to pneumococcal conjugate vaccine (PCV) are low in immunocompromised hosts. The effect of memory B cells on the immune response to PCV remains elusive.

METHODS

In this prospective study, 53 children who received 7-valent PCV were enrolled. Antipneumococcal immunoglobulin G (IgG) levels and opsonization index (OI) titers, along with lymphocyte subsets, were investigated in immunocompromised and immunocompetent hosts. Immunocompromised patients comprised 8 hematopoietic stem cell transplant recipients (group A) and 9 immunosuppressive therapy recipients (group B), and controls consisted of 14 children aged >1 year (group C) and 22 infants (group D).

RESULTS

Serotype-specific IgG concentrations and OIs in group A were lower than those in group C. These did not differ among groups B, C, and D. The rates of achieving immunity (defined as an IgG level of 1.0 µg/mL and an OI of 8) in group A were also lower than in group C. Despite the sustained numbers of total T cells and B cells, CD27(+) B-cell and CD4(+) T-cell counts in group A were lower than those in group C. In group B, the immunoglobulin D-expressing CD27(-) B-cell count was only lower than that in group C.

CONCLUSIONS

Circulating numbers of CD27(+) B cells, rather than CD4(+) T cells, may predict the effective PCV responses in immunocompromised children.

Clinical and genetic investigation of 17 Japanese patients with hyperekplexia

AIM

The aim of the study was to determine clinical and genetic characteristics of Japanese patients with hyperekplexia.

METHOD

Clinical courses, responses to antiepileptic drugs, outcomes, and genetic testing were investigated in 17 Japanese patients (nine males, eight females, median age 1y, range birth-45y) with hyperekplexia.

RESULTS

In all patients, muscle stiffness and startle responses appeared soon after birth. Only seven patients were diagnosed with hyperekplexia before 1 year of age. Seven patients had been misdiagnosed with other disorders such as epilepsy and adult-onset anxiety neurosis. Umbilical/inguinal hernias were seen in 10 patients. Life-threatening events were noted in four patients. Clonazepam was the most effective drug. Muscle stiffness completely disappeared in 12 patients before 5 years of age, whereas startle responses resolved in only three patients. Mutations in the GLRA1 and GLRB genes were identified in 16 patients and one patient respectively. In 14 patients, the mutation showed autosomal dominant inheritance; in the other three, inheritance was autosomal recessive. p.R271Q of GLRA1 was the most frequent mutation, found in 10 patients. Novel mutations, p.A272P and p.A384P of GLRA1, were detected. Clinical severity and outcome varied even in the same family.

INTERPRETATION

Early correct diagnosis is essential for prevention of accidental injuries and to provide appropriate treatments for hyperekplexia. Clonazepam is effective, although the time taken for startle responses to resolve varied.

Staphylococcal endocarditis as the first manifestation of heritable protein S deficiency in childhood

A 12-year-old Japanese girl developed infective endocarditis and central nervous system disease. The previously healthy girl showed altered consciousness and abnormal behaviors along with the classical signs of septic emboli. Staphylococcus aureus was isolated from peripheral blood, but not, the pleocytotic cerebrospinal fluid. Diagnostic imaging studies revealed a vegetative structure in the morphologically normal heart, and multiple thromboembolisms in the brain and spleen. Low plasma activity of protein S (12%) and thrombophilic family history allowed the genetic study, demonstrating that she carried a heterozygous mutation of PROS1 (exon 13; 1689C > T, p.R474C). Surgical intervention of the thrombotic fibrous organization and subsequent anticoagulant therapy successfully managed the disease. There are no reports of infective endocarditis in childhood occurring as the first presentation of heritable thrombophilia. Protein S deficiency might be a risk factor for the development or exacerbation of infective endocarditis in children having no pre-existing heart disease.

Development of Kawasaki disease in a patient with PFAPA

Periodic fever, aphthous stomatitis, pharyngitis and cervical adenitis syndrome (PFAPA) is one of the autoinflammatory diseases of unknown etiology characterized by regularly recurrent fever episodes with attacks lasting 3-6 days every 3-8 weeks associated with at least one of the three cardinal clinical signs: aphthous stomatitis, pharyngitis, and cervical adenitis. Kawasaki disease (KD) is an acute, self-limited systemic vasculitis that occurs predominantly in infants and young children. In most KD patients, i.v. immunoglobulin leads to a rapid amelioration of clinical symptoms and significantly decreases the risk of coronary artery aneurysms. Although the etiology of KD is still unknown, it was reported that innate immunity was activated in the patients. Described herein is a patient with PFAPA who developed KD. This is the first report of KD development in a PFAPA patient. The association between KD and PFAPA may represent a genetic predisposition to dysregulated innate immune response.

Neonatal hemophagocytic lymphohistiocytosis associated with a vertical transmission of coxsackievirus B1

Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening syndrome characterized by fever, cytopenias, hepatosplenomegaly, and coagulopathy with the background of hypercytokinemia. Early diagnosis and etoposide therapy are not established for affected newborns. An afebrile infant suffered from apnea 4 days after birth, showing leukocytosis, thrombocytopenia, coagulopathy, and cerebrospinal fluid pleocytosis. Serum levels of ferritin and sIL-2R were high. Bone marrow studies revealed activated/hemophagocytosing macrophages. Coxsackievirus B1 (CB1) was isolated from the throat and stool. Serum anti-CB1 antibody titers were elevated in the patient (4 → 16; 6 → 43 days after birth) and mother (128; 10 days after delivery). Normal expressions of perforin and CD107a precluded inherited HLH. The vertically transmitted CB1-HLH was successfully treated without administration of corticosteroid, cyclosporine, or etoposide. Serum cytokine levels showed dominant expression of monokines (IL-1β/6/8, and TNF-α) but not IFN-γ, which is the central player of inherited HLH. The cytokine profile might represent a unique pathophysiology of enterovirus-driven neonatal HLH.