Cholinergic sensing of allergen exposure by airway epithelium promotes type 2 immunity in the lungs

BACKGROUND

Nonneuronal cells, including epithelial cells, can produce acetylcholine (ACh). Muscarinic ACh receptor antagonists are used clinically to treat asthma and other medical conditions; however, knowledge regarding the roles of ACh in type 2 immunity is limited.

OBJECTIVE

Our aim was to investigate the roles of epithelial ACh in allergic immune responses.

METHODS

Human bronchial epithelial (HBE) cells were cultured with allergen extracts, and their ACh production and IL-33 secretion were studied in vitro. To investigate immune responses in vivo, naive BALB/c mice were treated intranasally with different muscarinic ACh receptor antagonists and then exposed intranasally to allergens.

RESULTS

At steady state, HBE cells expressed cellular components necessary for ACh production, including choline acetyltransferase and organic cation transporters. Exposure to allergens caused HBE cells to rapidly release ACh into the extracellular medium. Pharmacologic or small-interfering RNA-based blocking of ACh production or autocrine action through the M3 muscarinic ACh receptors in HBE cells suppressed allergen-induced ATP release, calcium mobilization, and extracellular secretion of IL-33. When naive mice were exposed to allergens, ACh was quickly released into the airway lumen. A series of clinical M3 muscarinic ACh receptor antagonists inhibited allergen-induced IL-33 secretion and innate type 2 immune response in the mouse airways. In a preclinical murine model of asthma, an ACh receptor antagonist suppressed allergen-induced airway inflammation and airway hyperreactivity.

CONCLUSIONS

ACh is released quickly by airway epithelial cells on allergen exposure, and it plays an important role in type 2 immunity. The epithelial ACh system can be considered a therapeutic target in allergic airway diseases.

Epithelial overexpression of IL-33 induces eosinophilic esophagitis dependent on IL-13

BACKGROUND

Eosinophilic esophagitis (EoE) is an increasingly common inflammatory condition of the esophagus; however, the underlying immunologic mechanisms remain poorly understood. The epithelium-derived cytokine IL-33 is associated with type 2 immune responses and elevated in esophageal biopsy specimens from patients with EoE.

OBJECTIVE

We hypothesized that overexpression of IL-33 by the esophageal epithelium would promote the immunopathology of EoE.

METHODS

We evaluated the functional consequences of esophageal epithelial overexpression of a secreted and active form of IL-33 in a novel transgenic mouse, EoE33. EoE33 mice were analyzed for clinical and immunologic phenotypes. Esophageal contractility was assessed. Epithelial cytokine responses were analyzed in three-dimensional organoids. EoE33 phenotypes were further characterized in ST2-/-, eosinophil-deficient, and IL-13-/- mice. Finally, EoE33 mice were treated with dexamethasone.

RESULTS

EoE33 mice displayed ST2-dependent, EoE-like pathology and failed to thrive. Esophageal tissue remodeling and inflammation included basal zone hyperplasia, eosinophilia, mast cells, and TH2 cells. Marked increases in levels of type 2 cytokines, including IL-13, and molecules associated with immune responses and tissue remodeling were observed. Esophageal organoids suggested reactive epithelial changes. Genetic deletion of IL-13 in EoE33 mice abrogated pathologic changes in vivo. EoE33 mice were responsive to steroids.

CONCLUSIONS

IL-33 overexpression by the esophageal epithelium generated immunopathology and clinical phenotypes resembling human EoE. IL-33 may play a pivotal role in the etiology of EoE by activating the IL-13 pathway. EoE33 mice are a robust experimental platform for mechanistic investigation and translational discovery.

Eosinophil Peroxidase: A Biomarker for Eosinophilic Chronic Rhinosinusitis Agnostic of Polyp Status

OBJECTIVE

To evaluate eosinophil peroxidase (EPX) as a biomarker for tissue levels of eosinophilia, cytokines, and chemokines within chronic rhinosinusitis (CRS).

METHODS

Twenty-eight subjects undergoing sinonasal surgery were prospectively enrolled. Ethmoid tissue was analyzed with an in-house EPX immunoassay and a 48-plex cytokine-chemokine array. Clinical severity was assessed using SNOT-22 and Lund-Mackay scores. Subjects were grouped as follows: controls, polyp status (CRS with [CRSwNP] and without nasal polyps [CRSsNP]), tissue eosinophilia (eosinophilic CRS [eCRS], non-eosinophilic CRS [neCRS]), or combinations thereof (eCRSwNP, eCRSsNP, neCRSsNP). eCRS was defined as >10 eosinophils per high power field (HPF). Subjects without CRS or asthma were enrolled as controls.

RESULTS

EPX was elevated in CRSwNP compared to control (p = 0.007), in eCRS compared to neCRS (p = 0.002), and in eCRSwNP along with eCRSsNP compared to neCRSsNP (p = 0.023, p = 0.015, respectively). eCRS displayed elevated IL-5 compared to neCRS (p = 0.005). No significant differences in EPX or IL-5 were observed between eCRSwNP and eCRSsNP. IL-5 was elevated in eCRSwNP (p = 0.019) compared neCRSsNP. Area under the receiver operator characteristic curve was 0.938 (95% CI, 0.835-1.00) for EPX and tissue eosinophilia, with an optimal cut-point of 470 ng/mL being 100% specific and 81.25% sensitive for tissue eosinophilia. Linear regression revealed a strong correlation between EPX and IL-5 (R2  = 0.64, p < 0.001). Comparing EPX and IL-5, only EPX displayed significant correlation with SNOT-22 (p = 0.04) and Lund-Mackay score (p = 0.004).

CONCLUSION

EPX is associated with tissue eosinophilia in CRS patients regardless of polyp status. EPX correlates with IL-5 and could be potentially considered a biomarker for anti-IL-5 therapies.

LEVEL OF EVIDENCE

3 Laryngoscope, 134:69-78, 2024.

Lung-resident CD69+ST2+ TH2 cells mediate long-term type 2 memory to inhaled antigen in mice

BACKGROUND

Chronic airway diseases such as asthma are characterized by persistent type 2 immunity in the airways. We know little about the mechanisms that explain why type 2 inflammation continues in these diseases.

OBJECTIVE

We used mouse models to investigate the mechanisms involved in long-lasting immune memory.

METHODS

Naive mice were exposed intranasally to ovalbumin (OVA) antigen with Alternaria extract as an adjuvant. Type 2 memory was analyzed by parabiosis model, flow cytometry with in vivo antibody labeling, and intranasal OVA recall challenge. Gene-deficient mice were used to analyze the mechanisms.

RESULTS

In the parabiosis model, mice previously exposed intranasally to OVA with Alternaria showed more robust antigen-specific immune responses and airway inflammation than mice with circulating OVA-specific T cells. After a single airway exposure to OVA with Alternaria, CD69+ST2+ TH2-type T cells, which highly express type 2 cytokine messenger RNA and lack CD62L expression, appeared in lung tissue within 5 days and persisted for at least 84 days. When exposed again to OVA in vivo, these cells produced type 2 cytokines quickly without involving circulating T cells. Development of tissue-resident CD69+ST2+ TH2 cells and long-term memory to an inhaled antigen were abrogated in mice deficient in ST2 or IL-33, but not TSLP receptor.

CONCLUSION

CD69+ST2+ TH2 memory cells develop quickly in lung tissue after initial allergen exposure and persist for a prolonged period. The ST2/IL-33 pathway may play a role in the development of immune memory in lung to certain allergens.

Allergen-induced DNA release by the airway epithelium amplifies type 2 immunity

BACKGROUND

Alternaria alternata and house dust mite exposure evokes IL-33 secretion from the airway epithelium, which functions as an alarmin to stimulate type 2 immunity. Extracellular DNA (eDNA) is also an alarmin that intensifies inflammation in cystic fibrosis, chronic obstructive pulmonary disease, and asthma.

OBJECTIVE

We investigated the mechanisms underlying allergen-evoked DNA mobilization and release from the airway epithelium and determined the role of eDNA in type 2 immunity.

METHODS

Human bronchial epithelial (hBE) cells were used to characterize allergen-induced DNA mobilization and extracellular release using comet assays to measure DNA fragmentation, Qubit double-stranded DNA assays to measure DNA release, and DNA sequencing to determine eDNA composition. Mice were used to investigate the role of eDNA in type 2 immunity.

RESULTS

Alternaria extract rapidly induces mitochondrial and nuclear DNA release from human bronchial epithelial cells, whereas house dust mite extract induces mitochondrial DNA release. Caspase-3 is responsible for nuclear DNA fragmentation and becomes activated after cleavage by furin. Analysis of secreted nuclear DNA showed disproportionally higher amounts of promotor and exon sequences and lower intron and intergenic regions compared to predictions of random DNA fragmentation. In mice, Alternaria-induced type 2 immune responses were blocked by pretreatment with a DNA scavenger. In caspase-3-deficient mice, Alternaria-induced DNA release was suppressed. Furthermore, intranasal administration of mouse genomic DNA with Alternaria amplified secretion of IL-5 and IL-13 into bronchoalveolar lavage fluid while DNA alone had no effect.

CONCLUSION

These findings highlight a novel, allergen-induced mechanism of rapid DNA release that amplifies type 2 immunity in airways.

Impact of the Comprehensive Awareness Modification of Mouth, Chewing and Meal (CAMCAM) Program on the Attitude and Behavior Towards Oral Health and Eating Habits as Well as the Condition of Oral Frailty: A Pilot Study

OBJECTIVES

Preserving sufficient oral function and maintaining aadequate nutrition are essential for preventing physical frailty and the following long-term care. We recently developed the 6-month Comprehensive Awareness Modification of Mouth, Chewing And Meal (CAMCAM) program, in which participants gather monthly to learn about oral health and nutrition while eating a textured lunch together. This study examined whether the CAMCAM program could improve attitude and behavior towards oral health, mastication, and diet as well as ameliorate oral frailty in community-dwelling older adults.

DESIGN

Single-arm pre-post comparison study.

SETTING AND PARTICIPANTS

A total of 271 community-dwelling adults (72.3 ± 5.7 years of age; 159 women [58.7%]) in 4 Japanese municipalities were recruited, of which 249 participants (92%) were assessed at the final evaluation.

INTERVENTION

Participants gathered once a month at community centers to learn about oral health and nutrition while eating a "munchy" textured lunch containing proper nutrition.

MEASUREMENTS

Oral frailty, frailty, and eating behavior were evaluated with the Oral Frailty Index-8 (OFI-8), Kihon checklist (KCL), and CAMCAM checklist, respectively. Participants were divided into Oral frailty (OF) and Robust groups according to OFI-8 scores. The differences in KCL and CAMCAM checklist results between the OF and Robust groups were statistically tested along with changes in scores after the program.

RESULTS

KCL and CAMCAM checklist scores were significantly lower in the OF group at the initial assessment. OFI-8 and KCL findings were significantly improved in the OF group after completing the program (all P <0.05). Regarding the CAMCAM checklist, awareness of chewing improved significantly in the Robust group (P=0.009), with a similar tendency in the OF group (P=0.080).

CONCLUSION

The findings of this pilot study suggest that the CAMCAM program may improve both oral and systemic frailty in addition to attitudes towards chewing, oral health, and meals, especially in individuals with oral frailty. The CAMCAM program merits expansion as a community-based frailty prevention program.

Testing mosses exposed in bags as biointerceptors of airborne radiocaesium after the Fukushima Dai-ichi Nuclear Power Station accident

Eight years after the Fukushima nuclear accident, mosses exposed in bags were used to investigate their ability to accumulate radiocaesium and therefore to act as biointerceptors of ¹³⁴Cs and ¹³⁷Cs in the evacuated area of the Fukushima territory. Bags were filled with 3 widely studied moss species (Sphagnum palustre, Hypnum cupressiforme, and Hypnum plumaeforme) and exposed for 3, 6 or 9 weeks at 5 former residential sites within the Fukushima area and, for comparison, at three background sites located 700 km away. The radiocaesium activity concentrations found in moss bags were evaluated as function of exposure time, site conditions and moss species. In the Fukushima area, the moss bags accumulated ¹³⁷Cs at all exposure sites and in all exposure periods, with S. palustre having the highest ¹³⁷Cs accumulation ability. The ¹³⁷Cs activity concentrations (from 28 to 4700 Bq kg^-1) measured in moss bags increased with the exposure time and were consistent with the decontamination status of each exposure site, highlighting the big potential of moss bags to discriminate among exposure sites. Time dependency of ¹³⁷Cs activity concentrations measured in mosses allowed the calculation of location-specific and species-specific factors, which can be used to predict radiocaesium accumulation trends in future biomonitoring surveys performed in the same area with the same experimental design. Autoradiography and electron microscopy analyses of the moss surfaces revealed a prevalence of soil-derived particulate form of radiocaesium, suggesting the use of moss bags as warning sensors of resuspended particles potentially harmful for local residents.

Physiological microbial exposure transiently inhibits mouse lung ILC2 responses to allergens

Lung group 2 innate lymphoid cells (ILC2s) control the nature of immune responses to airway allergens. Some microbial products, including those that stimulate interferons, block ILC2 activation, but whether this occurs after natural infections or causes durable ILC2 inhibition is unclear. In the present study, we cohoused laboratory and pet store mice as a model of physiological microbial exposure. Laboratory mice cohoused for 2 weeks had impaired ILC2 responses and reduced lung eosinophilia to intranasal allergens, whereas these responses were restored in mice cohoused for ≥2 months. ILC2 inhibition at 2 weeks correlated with increased interferon receptor signaling, which waned by 2 months of cohousing. Reinduction of interferons in 2-month cohoused mice blocked ILC2 activation. These findings suggest that ILC2s respond dynamically to environmental cues and that microbial exposures do not control long-term desensitization of innate type 2 responses to allergens.

Blocking the inhibitory receptor programmed cell death 1 prevents allergic immune response and anaphylaxis in mice

BACKGROUND

Food allergy and acute anaphylaxis can be life-threatening. While T follicular helper (Tfh) cells play a pivotal role in the allergic immune responses, the immunologic mechanisms that regulate the production of antibodies (Abs) that mediate anaphylaxis are not fully understood.

OBJECTIVE

The aim of this study was to investigate the role of the inhibitory receptor programmed cell death protein 1 (PD-1), which is highly expressed on Tfh cells, in allergic immune responses using an animal model of peanut allergy and anaphylaxis.

METHODS

Naive wild-type mice were exposed to peanut flour intranasally and then challenged with peanut extract to induce systemic anaphylaxis. The roles of PD-1 were examined by blocking Abs and using gene-deficient animals. A hapten model and passive cutaneous anaphylaxis were used to characterize allergen-specific Abs.

RESULTS

Treatment with anti-PD-1 enhanced development of Tfh cells and germinal center B cells in mice exposed to peanut flour. Nonetheless, anti-PD-1 or its ligand fully protected mice from developing anaphylaxis. Anti-PD-1 treatment or genetic deficiency of PD-1 in CD4⁺ T cells inhibited production of peanut-specific IgE and increased the levels of IgG. The passive cutaneous anaphylaxis showed that peanut-specific Abs generated in anti-PD-1-treated animals prevented, rather than provoked, anaphylaxis when transferred to naive animals. Anti-PD-1 promoted production of Abs with low affinity for an antigen in the hapten model.

CONCLUSION

Blockade of the pathway between PD-1 and its ligand is protective against allergic immune responses. The direct interaction between Tfh cells and B cells may play a pivotal role in controlling Ab quality and clinical manifestation of allergic diseases.

OP0008 A NOVEL SITE-SPECIFIC PEGYLATED IL-2 WITH POTENT AND TREG-SELECTIVE ACTIVITY IN VIVO

Background

Decreased regulatory T cells (Tregs) and Treg dysfunction are hallmarks of a various autoimmune and inflammatory diseases. While low-dose IL-2 therapy induces Treg expansion in vivo and has clinical benefits in some diseases (e.g., SLE and chronic graft-versus-host disease [GvHD]), there are many concerns about adverse events due to low Treg-selectivity. Furthermore, frequent dosing is needed due to the short half-life.

Objectives

We discovered a novel site-specific PEGylated IL-2 variant, KKC80, with high Treg selectivity and a long half-life in vivo, which overcomes the issues of low-dose IL-2 therapy.

Methods

Based on the co-crystal structure of wild-type IL-2 and its heterotrimeric receptor (PBD ID: 2ERJ), amino acid residues that were to be PEGylation sites were substituted with oAzZLys, an azide-containing lysine derivative. The PEG molecule was site-specifically attached to oAzZLys-incorporated IL-2 by copper-free click chemistry. The binding property to the IL-2 receptors were measured by surface plasmon resonance (SPR). In vitro, Treg selectivity was evaluated by the IL-2-dependent proliferation activity of Tregs and NK cells from human peripheral blood mononuclear cells (PBMCs). In vivo pharmacological activity after the single subcutaneous administration in cynomolgus monkeys was measured by changes in Treg count and Treg activation status in peripheral blood by flow cytometry. Pharmacokinetic parameters were calculated according to serum PEGylated IL-2 concentration. Efficacy in mouse xenogeneic GvHD model using human PBMC-transplanted NOG mice and in monkey DTH model were evaluated.

Results

A novel PEGylated IL-2, KKC80 (human IL-2 desA1/C125S /I129oAzZLys_W-shaped 80 kDa PEG) was discovered by optimizing the PEGylation site and PEG structure based on Treg selectivity and PK. SPR analysis showed that the binding affinity of KKC80 to CD25 was moderately decreased from wild-type IL-2, while binding affinity of KKC80 to IL-2Rβγ was remarkably decreased due to a significant change of the association rate constant. In vitro, wild-type IL-2 activated both Tregs and NK cells in the same concentration range, whereas KKC80 selectively activated Tregs. The Treg selectivity of KKC80 was comparable to another IL-2 mutein, Fc.IL-2 V91K. KKC80, but not Fc.IL-2 V91K, retained its biological activity, even in the presence of a large amount of recombinant soluble CD25, which mimicked the endogenous decoy receptor for IL-2. In monkeys, KKC80 selectively increased peripheral blood Tregs in a dose-dependent manner; the average maximum rate of increase of Treg count in animals treated with 0.01, 0.03, 0.1, 0.3 and 1 mg/kg was 1.5, 3.5, 28, 50 and 154-fold, respectively. In contrast to Tregs, the rates of increase of conventional CD4+ T, CD8+ T and NK cells were low. The Treg increase peaked on day 8 or 11 and lasted for over day 29. KKC80 showed a more sustained upregulation of functional Treg markers (e.g., Foxp3 and CD25) in comparison to Fc.IL-2 V91K. The half-life of KKC80 was calculated as 83.5 to 150 h. At high doses, inflammation-related adverse effects, including increased CRP (≥0.3 mg/kg) and deterioration of general conditions (1 mg/kg) were observed. In the mouse xenogenic GvHD model, KKC80 ameliorated GvHD symptoms and suppressed multiple tissue inflammation markers. Decreased soluble CD25 and IFN-γ were also confirmed, suggesting Treg-mediated anti-inflammatory effect by KKC80 administration were exerted in vivo. In the monkey DTH model, KKC80 suppressed skin inflammation and antibody production.

Conclusion

Among next-generation IL-2 variants, KKC80 showed a best-in-class biological profile for Treg activation. A drastic and sustained increase of Tregs with high Treg-selectivity and anti-inflammatory effects were observed in vivo. These data suggest that in comparison to current IL-2 therapy, KKC80 provides superior therapeutic index and efficacy in patients with autoimmune and inflammatory diseases.

Figure 1.

Disclosure of Interests

Masahiro Ikeda Employee of: Kyowa Kirin Co., Ltd., Shinpei Yamaguchi Employee of: Kyowa Kirin Co., Ltd., Masumi Murakami Employee of: Kyowa Kirin Co., Ltd., Shigeki Takaoka Employee of: Kyowa Kirin Co., Ltd., Yasuko Sakaguchi Employee of: Kyowa Kirin Co., Ltd., Shunki Yasui Employee of: Kyowa Kirin Co., Ltd., Kousuke Iijima Employee of: Kyowa Kirin Co., Ltd., Kenichiro Nanya Employee of: Kyowa Kirin Co., Ltd., Hideyuki Onodera Employee of: Kyowa Kirin Co., Ltd., Toru Amano Employee of: Kyowa Kirin Co., Ltd.

PD-1 blockade in T follicular helper cells protects mice from peanut allergy by promoting production of low-affinity antibodies

Food allergy, such as peanut allergy can cause life-threatening anaphylaxis. While T follicular helper (Tfh) cells play a major role in production of allergen-specific IgE and IgG antibodies, the immunologic mechanisms that regulate the production of antibodies that mediate anaphylaxis are not well understood. While PD-1 is highly expressed on Tfh cells, our knowledge is limited regarding the role of the molecule in Tfh cells. Thus, the objective of this study was to investigate the roles of PD-1 in allergic immune responses using a mouse model of peanut allergy. Naïve wild-type mice were exposed to peanut flour intranasally (i.n.) and then challenged by intraperitoneal (i.p.) injection of peanut extract. The mice exposed i.n. to peanut flour produced peanut-specific IgE and IgG antibodies and developed anaphylaxis when challenged i.p. with peanut extract. PD-1 blockade with anti-PD-1 treatment Tfh and germinal center B cell numbers in mice exposed to peanut flour. Nonetheless, anti-PD-1 or anti-PD-L1 fully protected mice from anaphylaxis. Anti-PD-1 or genetic deficiency of PD-1 in CD4+ T cells reduced and increased levels of peanut-specific IgE and IgG, respectively. Anti-PD-1 promoted production of low-affinity IgE and IgG antibodies with no effect on high-affinity antibodies. By passive cutaneous anaphylaxis, peanut-specific antibodies generated in anti-PD1 treated mice failed to induce anaphylaxis, and plasma from these mice prevented anaphylaxis. Therefore, blockade of the PD-1 pathway is protective against allergic immune responses. The interaction between Tfh cells and B cells may play a pivotal role in controlling antibody quality and clinical manifestation of allergic diseases.

Social Detachment Influenced Muscle Mass and Strength during the COVID-19 Pandemic in Japanese Community-Dwelling Older Women

Social detachment due to coronavirus disease (COVID-19) has caused a decline in physical activity, leading to sarcopenia and frailty in older adults. This study aimed to compare muscle mass, strength, and function values in older women before and after the first wave of the COVID-19 pandemic (April-May 2020). Furthermore, changes in muscle measures across women who experienced different levels of impact on their social participation due to the COVID-19 pandemic were examined. Muscle mass (total, trunk, and appendicular muscle), grip strength, oral motor skills, social interactions (social network and participation), and social support were assessed in 46 Japanese community-dwelling older women (mean, 77.5 y; range 66-93 y) before and after the first wave of the COVID-19 pandemic. Trunk muscle mass significantly decreased after the first wave of the pandemic. When comparing changed values between the enhanced/maintained and reduced group during the pandemic, significant group difference was observed in trunk muscular mass, grip strength, and oral motor skills. Intriguingly, those who enhanced social participation had a positive change of grip strength values, showing that social participation might influence muscle function during the COVID-19 pandemic.

A Mouse Model of the “LEAP” Study Reveals a Role for CTLA-4 in Preventing Peanut Allergy Induced by Environmental Peanut Exposure

BACKGROUND

A human study, Learning Early About Peanut Allergy (LEAP), showed that early introduction of peanut products decreases the prevalence of peanut allergy among children. However, the immunologic mechanisms mediating the protective effects of consuming peanut products are not well understood.

OBJECTIVE

The objective was to develop a mouse model that simulates the LEAP study and investigate the underlying mechanisms for the study observations.

METHODS

Adult naive BALB/c mice were fed a commercial peanut butter product (Skippy) or buffer control and concomitantly exposed to peanut flour through the airway or skin to mimic environmental exposure. The animals were analyzed for anaphylactic reaction and by molecular and immunologic approaches.

RESULTS

After exposure to peanut flour through the airway or skin, naive mice developed peanut allergy, as demonstrated by acute and systemic anaphylaxis in response to challenge with peanut extract. Ingestion of Skippy, however, nearly abolished the increase in peanut-specific IgE and IgG and protected animals from developing anaphylaxis. Skippy-fed mice showed reduced numbers of T follicular helper (Tfh) cells and germinal center B cells in their draining lymph nodes, and single-cell RNA sequencing revealed a CD4⁺ T-cell population expressing cytotoxic T lymphocyte-associated protein 4 (CTLA-4) in these animals. Critically, blocking CTLA-4 with antibody increased levels of peanut-specific antibodies and reversed the protective effects of Skippy.

CONCLUSION

Ingestion of a peanut product protects mice from peanut allergy induced by environmental exposure to peanuts, and the CTLA-4 pathway, which regulates Tfh cell responses, likely plays a pivotal role in this protection.

TRENDS IN THE PREVALENCE OF FRAILTY IN JAPAN: A META-ANALYSIS FROM THE ILSA-J

OBJECTIVE

To examine whether age-specific prevalence of frailty in Japan changed between 2012 and 2017.

DESIGN

This study performed meta-analyses of data collected from 2012 to 2017 using the Integrated Longitudinal Studies on Aging in Japan (ILSA-J), a collection of representative Japanese cohort studies.

SETTING

The ILSA-J studies were conducted on community-living older adults.

PARTICIPANTS

ILSA-J studies were considered eligible for analysis if they assessed physical frailty status and presence of frailty in the sample. Seven studies were analyzed for 2012 (±1 year; n = 10312) and eight studies were analyzed for 2017 (±1 year; n = 7010). Five studies were analyzed for both 2012 and 2017.

MEASUREMENTS

The study assessed the prevalence of frailty and frailty status according to 5 criteria: slowness, weakness, low activity, exhaustion, and weight loss.

RESULTS

The overall prevalence of physical frailty was 7.0% in 2012 and 5.3% in 2017. The prevalence of frailty, especially in people 70 years and older, tended to decrease in 2017 compared to 2012. Slight decreases were found in the prevalence of frailty subitems including weight loss, slowness, exhaustion, and low activity between 2012 and 2017, but change in the prevalence of weakness was weaker than other components.

CONCLUSIONS

The prevalence of physical frailty decreased from 2012 to 2017. There are age- and gender-related variations in the decrease of each component of frailty.

PD-1 regulates affinity maturation of allergen-specific antibodies and severity of peanut allergy in mice

Programmed cell death-1 (PD-1), a member of the CD28 family, is critical for regulation of immune cell activation and maintenance of peripheral tolerance. Blocking antibodies against PD-1 have been used to sustain activation of T cells in cancer immunotherapy. T follicular helper (Tfh) cells play important role in the differentiation and maturation of antigen-specific B cells. Tfh cells highly and constitutively express PD-1; however, our knowledge is limited regarding the role of PD-1 in Tfh cell function and antibody response. We addressed this question by using a Tfh-dependent mouse model of peanut allergy. When naïve BALB/c mice were exposed to peanut flour by inhalation for 4 weeks, they developed peanut allergy as demonstrated by increased plasma levels of peanut-specific IgE and IgG antibodies and manifestation of acute anaphylaxis upon challenge with peanut extract. To examine the roles of PD-1, we administered a PD-1 blocking antibody to the animals during their exposure to peanut flour. Mice administered anti-PD-1 did not develop anaphylaxis even when they were challenged with peanut extract. Anti-PD1 treatment increased the number of Tfh cells and germinal center B cells in draining lymph nodes, and it increased plasma levels of peanut-specific IgG antibodies. Importantly, PD-1 blockade promoted the accumulation of low-affinity antibodies while it maintained the levels of high-affinity antibodies. These findings suggest that quality of allergen-specific antibodies affects the severity of allergic immune responses. Understanding the mechanisms that explain how PD-1 regulates the Tfh-B interaction and affinity maturation of antibodies likely leads to a better understanding of pathophysiology of allergic diseases.

A history of microbial exposures has a temporally limited inhibitory effect on mouse lung ILC2 responses to a fungal allergen

The ability of some microbes and their products to restrain the immune response to allergens has been extensively studied and is a key element of the hygiene hypothesis. However, it is unclear whether a modulated immune response relates to recent microbial exposure, or whether a diverse infectious history promotes sustained changes in reactivity to allergens. Thus, we explored how prior microbial experience in “dirty” mice affected innate immune responses to an airway fungal allergen. Dirty mice were generated by cohousing laboratory mice with pet store mice for at least 60 days to allow for physiological transmission of microbes. Despite changes induced in many immune cell populations, lung type 2 innate lymphoid cell (ILC2) numbers and phenotype were unaltered by cohousing. Short term (4.5 hour) production of the type 2 cytokines IL-5 and IL-13 in response to Alternaria alternata extract was consistently depressed in dirty mice relative to specific pathogen free (SPF) and germ-free animals. This correlated with diminished release of IL-33, an alarmin that activates ILC2, in dirty mice. Nevertheless, at a later timepoint (24 hours) or after repeated Alternaria exposure, the influx of eosinophils, neutrophils and T cells into the lungs was similar in dirty and SPF mice. Our data therefore indicate that a history of robust and diverse microbial exposure delays but ultimately does not restrain development of a type 2 response to airway allergens, in contrast to the established inhibitory effects of acute exposure to certain microbes and their products.

Association of residual gastric acid secretion with persistent symptoms in gastroesophageal reflux disease patients receiving standard-dose proton pump inhibitor therapy

BACKGROUND

Although a third of gastroesophageal reflux disease (GERD) patients are refractory to proton pump inhibitor (PPI) therapy, the underlying mechanism of the refractoriness remains unclear. We compared the level of gastric acid suppression during PPI treatment between responders and non-responders by directly measuring gastric acid secretion in GERD patients taking PPIs.

METHODS

Seventy-five consecutive patients receiving standard-dose PPI therapy for GERD were prospectively recruited, irrespective of persistent GERD symptoms. They were asked about their GERD symptoms using a validated questionnaire, and simultaneously underwent both a routine endoscopic examination and a gastric acid secretory testing using an endoscopic gastrin test. Associations between residual gastric acid secretion during PPI treatment and persistent GERD symptoms were analyzed by a logistic regression analysis.

RESULTS

Overall, 26 of 75 (34.7%) patients were judged to be positive for persistent GERD symptoms. The patients with and without persistent symptoms showed similar gastric acid secretion levels (1.3 [1.3] mEq/10 min vs. 1.4 [2.0] mEq/10 min). Sufficient gastric acid suppression, defined as < 0.6, was not significantly associated with persistent GERD symptoms (odds ratio 1.1, 95% confidence interval 0.40-3.5).

CONCLUSIONS

This study provided solid evidence to support that the gastric acid suppression level during PPI treatment does not differ between patients with and without persistent GERD symptoms. The insignificant role of residual gastric acid in the persistent GERD symptoms suggests that the use of medications other than those that enhance gastric acid inhibitory effects would be an essential approach for the management of PPI-refractory GERD.

Frailty Checkup Supporters' Intentions to Participate in Human-Resource Development and Training Activities

BACKGROUND

Frailty prevention is one of social prescriptions for an aging society. That requires community level intervention.

OBJECTIVES

This study examined frailty checkup supporters' (FCSs') intentions to engage in human-resource development and training activities (i.e., leadership activities) and related factors.

DESIGN

Cross-sectional study.

SETTING

Three municipalities in suburban area, Eastern Japan.

PARTICIPANTS

Forty-five of 59 FCSs completed anonymous self-administered questionnaires.

MEASUREMENTS

Questionnaire sought information regarding their sociodemographic data, their perceptions and experiences of FCS activities, and their intentions to participate in human-resource development and training activities. Participants were divided into a high intention (HI) and low intention group (LI). The two groups were compared using quantitative and qualitative data.

RESULTS

Eleven FCSs reported intending to engage in leader-related activities. Factors associated with FCSs' intentions were finding FCS activities rewarding and the willingness to continue performing FCS activities. The participants who changed their daily activities (p = .041) and perceptions regarding contributing to the community (p = .018) showed significantly higher intention than LI participants. Free description about the changes in perceptions and lifestyles as a consequence of participating in FCS activities were analyzed qualitatively. FCSs who changed their daily activities and perspectives about contributing to the community described positive changes in both the groups. Meanwhile, FCSs who did not change their daily activities and perspectives about contributing to the community described their reason only in the LI group.

CONCLUSIONS

The results might encourage FCSs to participate in training and guidance activities, as they have positive experiences and receive recognition obtained through participation in such activities.

Group 2 Innate Lymphoid Cells Promote Development of T Follicular Helper Cells and Initiate Allergic Sensitization to Peanuts

Peanut allergy is a growing public concern; however, little is known about the immunological mechanism(s) that initiate the disease process. Our knowledge is also limited regarding the role of group 2 innate lymphoid cells (ILC2s) in regulating humoral immunity. To fill these major gaps in our knowledge, we investigated the immunological mechanisms involved in peanut allergen sensitization by using mouse models. To mimic environmental exposure in humans, naive BALB/c mice were exposed to peanut flour by inhalation without any exogenous adjuvants. When exposed to peanut flour, naive mice developed T follicular helper (Tfh) cells in their lung draining lymph nodes and produced IgE Abs to peanuts. Mice deficient in IL-13 showed decreased numbers of Tfh cells and germinal center B cells and produced significantly fewer IgE Abs. IL-13 was necessary and sufficient for induction of CD11c⁺ MHC class II^hi dendritic cells that are implicated in Tfh cell development. Importantly, lung ILC2s served as a predominant early source of IL-13 when naive mice were exposed to peanut flour. Furthermore, mice that are deficient in lung ILC2s by bone marrow transfer from Rora ^sg/sg mice or by genetic manipulation produced significantly fewer IgE Abs to peanuts compared with control mice. These findings suggest lung ILC2s that serve as a rapid source of IL-13 upon allergen exposure play a major role in Tfh cell development, IgE Ab production, and initiation of peanut allergy.

Lung ILC2 responses to Alternaria alternata fungal allergen are blunted in “dirty” mice with physiologically transmitted murine microbes

The objective of this study was to test the hypothesis that the increasing global incidence of allergy and atopy are due in part to improved hygiene and decreased microbial exposure. We have adopted a novel mouse model of normalized microbial exposure to test the impact of immune experience on subsequent responses to airway allergens. In this model, specific pathogen free (SPF) B6 mice are cohoused with mice from pet stores and become “dirty” – many commensals and pathogens are transmitted through cohousing and influence the immune cell populations systemically and in the lungs. We treated mice intranasally with a single dose of A. alternata fungal extract (Alt) and assessed production of type 2 cytokines. IL5 and IL13 levels in the lungs and bronchoalveolar lavage fluid were dramatically elevated by Alt in SPF mice but were not significantly increased by Alt in dirty mice. Type 2 innate lymphoid cells (ILC2) are the cells responsible for IL5 and IL13 after acute Alt treatment, and interestingly the number of lung ILC2 was unaltered by cohousing and their activation status appeared similar in both housing conditions. We treated mice with recombinant IL33, the alarmin released by lung epithelial cells in response to allergens, and the results suggest an impaired response to IL33 by dirty lung ILC2. In a repeated Alt exposure model, ILC2 cells expanded in SPF lungs and recruited eosinophils, neutrophils, and T cells. Most dirty mouse lungs contained these cell populations at steady state but were only modestly recruited with repeated Alt exposure. Lung function experiments are in progress. This study suggests that increased microbial exposure leads to more type-2 associated immune cells in the lungs, however responses to airway allergens are dampened.

Association between Traditional Japanese Diet Washoku and Sarcopenia in Community-Dwelling Older Adults: Findings from the Kashiwa Study

OBJECTIVES

To identify the dietary patterns among community-dwelling Japanese older adults and to explore the association between these patterns and sarcopenia.

DESIGN

Cross-sectional study.

SETTING

Kashiwa city, Chiba prefecture, Japan.

PARTICIPANTS

Community-dwelling older adults (n = 1241) aged 65 years and over who were not eligible for long-term care.

MEASUREMENTS

Dietary intake was assessed using the brief self-administered diet history questionnaire (BDHQ). Dietary patterns were identified using both principal component analysis and the score on the Japanese diet comprising soybeans and soybean products, fish, vegetables, pickles, mushroom, seaweeds, and fruits. Sarcopenia was defined by the Asian Working Group for Sarcopenia (AWGS) criteria. A binary logistic regression analysis was performed with sarcopenia status as the dependent variable after adjusting for economic status, living alone status, BMI, energy intake, multimorbidity, and physical activity.

RESULTS

Participants' mean age was 74.6 years, and 52.1% were male. According to AWGS criteria, 5.1% had sarcopenia. Three dietary patterns were identified from the principal component analysis. Dietary pattern 1 (DP1), showed high loadings for fish, tofu, vegetables, and fruits which are similar to the side dishes in a typical Japanese diet. Dietary pattern 2 (DP2) had high factor loadings for fish, rice, and miso soup which are main dishes in a typical Japanese diet. Dietary pattern 3 (DP3) had a high factor loading for noodles. Men with the lowest tertile of DP1 score had a higher likelihood of being sarcopenic (Adjusted odds ratio (AOR) 3.67, 95% confidence interval (CI) 1.20-11.2). Women with the lowest tertile of DP2 score had a moderate likelihood of being sarcopenic (AOR 2.71, 95%CI 0.99-7.46). Low adherence to Japanese dietary pattern was associated with prevalence of sarcopenia in both genders.

CONCLUSION

Adherence to a dietary pattern high in foods characteristic of a Japanese diet including fish, soybean products, vegetables, and fruits was associated with low prevalence of sarcopenia in both genders.

Living with Family yet Eating Alone is Associated with Frailty in Community-Dwelling Older Adults: The Kashiwa Study

OBJECTIVES

Eating alone is related to depression, nutritional risk, and mortality. These effects are also influenced by living status. However, little is known about the relationship between eating alone despite living with family and frailty. This study explores the relationship of eating alone and living status with frailty in community-dwelling older adults.

DESIGN

Cross-sectional study.

SETTING AND PARTICIPANTS

Kashiwa city, Chiba prefecture, Japan; randomly selected community-dwelling older adults (aged 65 years and over).

MEASUREMENTS

Eating status was assessed by the question, "Do you eat meals with anyone, at least once a day: yes or no?" Frailty was defined by Kihon Checklist (KCL) score 8 or over. Domains of frailty were divided into instrumental activities of daily living (IADL), physical strength, nutrition, eating, socialization, memory, and mood, based on KCL categories. Binary logistic regression analysis was used, adjusting for age, years of education, chronic diseases, number of teeth and cognitive function.

RESULTS

Among the total of 1,914 participants, 49.8% were male, and the overall mean age was 72.9 ± 5.5 years. Of all participants, 56 (5.9%) of men and 112 (11.7%) of women were frail. Older adults who ate alone despite living with others were more likely to be frail (OR 2.49, 95%CI 1.1-5.5 for men and OR 2.16, 95%CI 1.0-4.5 for women). Of particular note, eating and living status were associated with lower physical strength and mood in men, whereas in women these statuses were associated with lower scores for IADL, socialization, memory, and mood.

CONCLUSIONS

Eating alone despite living with others was associated with high frailty in both genders; however, the pathways were different between genders. These results might help yield a simple, fundamental intervention approach to multifaceted frailty, reflecting gender and associated high-risk domains.

Early Life Represents a Vulnerable Time Window for IL-33-Induced Peripheral Lung Pathology

IL-33, an IL-1 family cytokine, is constitutively expressed in mucosal tissues and other organs in healthy humans and animals, and expression levels increase in inflammatory conditions. Although IL-33-mediated promotion of type 2 immune responses has been well established, a gap in our knowledge regarding the functional diversity of this pleiotropic cytokine remains. To address this gap, we developed a new IL-33 transgenic mouse model in which overexpression of full-length IL-33 is induced in lung epithelial cells under conditional control. In adult mice, an ∼3-fold increase in the steady-state IL-33 levels produced no pathologic effects in the lungs. When exposed to airborne allergens, adult transgenic mice released more IL-33 extracellularly and exhibited robust type 2 immune responses. In neonatal transgenic mice, up to postnatal day 14, a similar increase in steady-state IL-33 levels resulted in increased mortality, enlarged alveolar spaces resembling bronchopulmonary dysplasia, and altered expression of genes associated with tissue morphogenesis. Processed 25-kDa IL-33 protein was detected in bronchoalveolar lavage fluids without any exogenous stimuli, and pathologic changes were abolished in mice deficient in the IL-33 receptor ST2. These findings suggest that adult lungs are relatively resistant to IL-33 overexpression unless they encounter environmental insults, whereas developing lungs are highly susceptible, with IL-33 overexpression resulting in detrimental and pathologic outcomes.

Radiologic and Pathologic Features of the Transmantle Sign in Focal Cortical Dysplasia: The T1 Signal Is Useful for Differentiating Subtypes

BACKGROUND AND PURPOSE

The transmantle sign is a characteristic MR imaging finding often seen in focal cortical dysplasia type IIb. The transmantle sign is typically hyperintense on T2WI and FLAIR and hypointense on T1WI. However, in some cases, it shows T1 high signal. We evaluated the imaging and pathologic findings to identify the causes of the T1 high signal in the transmantle sign.

MATERIALS AND METHODS

We retrospectively reviewed the preoperative imaging data of 141 consecutive patients with histologically proved focal cortical dysplasia. We selected 25 patients with focal cortical dysplasia with the transmantle sign and divided them into groups based on the pathologic focal cortical dysplasia subtype and T1 signal of the transmantle sign. We evaluated the clinical, radiologic, and pathologic findings, including the number of balloon cells and dysmorphic neurons and the severity of gliosis or calcifications and compared them among the groups.

RESULTS

Nine of the 25 patients had a T1-high-signal transmantle sign; the other 16 patients did not. All 9 patients with a T1-high-signal transmantle sign were diagnosed as type IIb (group A). Of the 16 patients with no T1-high-signal transmantle sign, 13 were diagnosed as having type IIb (group B), and the other 3 patients, as type IIa (group C). The number of balloon cells was significantly higher in group A than in the other groups, but there were no differences regarding dysmorphic neurons, the severity of gliosis, or calcifications.

CONCLUSIONS

Approximately 6% (9/141) of this patient series had a T1-high-signal transmantle sign, and all were type IIb. The signal may reflect a rich density of balloon cells. This finding could support the differentiation of subtypes, especially type IIb.

Oral tolerance to peanut allergy is mediated by CTLA-4-positive regulatory T cells

Peanut allergies are life-long diseases that cause severe anaphylactic responses to affected individuals. Oral ingestion of peanut products prevents infants from developing peanut allergy. However, little information is currently available regarding the immunologic mechanisms for this protection. Therefore, the goal of this project was to establish an oral tolerance model to peanut allergy in mice and to determine the immunologic mechanisms.

Naïve BALB/c mice that were exposed intranasally (i.n.) to peanut flour (PNf) developed peanut allergy as demonstrated by increased serum levels of IgE antibody as well as acute anaphylactic response when challenged with peanut extract. When mice were fed peanut butter (PNB) prior to i.n PNf exposure, they were protected from developing peanut allergy; these mice showed decreased serum levels of IgE antibody and lacked anaphylactic response. T follicular helper (Tfh) cells and germinal center (GC) B cells were decreased in lung draining lymph nodes of mice fed PNB. Furthermore, scRNSseq revealed 2 distinct CD4+ T cell subpopulations that are increased in those protected mice. CTLA-4, a checkpoint molecule, was highly expressed in one of these subpopulations. Systemic administration of a CTLA-4 blocking antibody to mice fed PNB increased the numbers of Tfh cells and GC B cells and increased serum levels of IgE antibody. Finally, anti-CTLA-4 reversed the clinical efficacy of oral PNB administration, resulting in manifestation of acute anaphylaxis when challenged with peanut extract.

Thus, oral administration of peanut product(s) prevents development of peanut allergy in mice. CTLA4+CD4+ T cells likely play a pivotal role in this process by regulating the development of Tfh cells.