Genetic diversity and differentiation analysis reveals geographical structure characteristics of Dermatophagoides farinae (Acari: Pyroglyphidae).

Dermatophagoides farinae (Acari: Pyroglyphidae) has been reported as one of the major sources of indoor allergens that trigger allergic disease in humans. In this study, the genetic diversity and differentiation of nine geographic populations of D. farinae were investigated by analyzing mitochondrial and nuclear genes (COI, Cytb, COI+Cytb, and ITS). The results showed high genetic diversity across the D. farinae populations. The BX (Benxi) population showed the lowest genetic diversity, possibly due to climatic causes. Significant genetic differentiation was observed among D. farinae populations based on mitochondrial genes. The analysis of molecular variance (AMOVA) results elucidated that the contribution to the rate of variation was primarily from among populations. Phylogenetic analysis and haplotype network based on mitochondrial genes both indicated significant geographic structure among D. farinae populations. The nine geographic populations of D. farinae were divided into two groups with the Qinling Mountains-Huai River Line serving as the boundary for spatial analysis of molecular variance analysis (SAMOVA). However, the Mantel test analysis showed no association between genetic differentiation and geographic distance because of the high level of gene flow among some populations through the transportation of stored food. Overall, these results indicate both significant genetic differentiation among D. farinae populations, but also significant gene exchange between them. Results from the analysis of the nuclear gene ITS differed from the mitochondrial genes due to differences in molecular markers between mitochondrial genes and nuclear genes. These observations improve our understanding of the genetic diversity and structure of D. farinae populations.

Oral Ingestion of Yuzu Seed Oil Suppresses the Development of Atopic Dermatitis-like Skin Lesions in NC/Nga Mice.

Long-term oral ingestion of unheated yuzu seed oil in humans reduces lipid peroxides in the blood. Moreover, yuzu seed oil contains limonin, which can induce antioxidant and anti-inflammatory effects by activating the transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2). Previously, Nrf2 has been shown to reduce atopic dermatitis (AD). Therefore, we hypothesized that ingesting unheated yuzu seed oil can regulate AD through Nrf2. An AD model was established using NC/Nga mice through repeated local exposure to mite antigens. Unheated and purified yuzu seed oil (100 µL/mice) or water (control, 100 µL/mice) was administered orally once a day using a gastric cannula for rodents for 28 days. On day 28, mice in the unheated yuzu seed oil group exhibited significantly lower clinical skin severity scores and ear thickness than those in the purified yuzu seed oil and water groups. Serum histamine levels remained unaltered among the three AD-induced groups. Serum Dermatophagoides farina body (Dfb)-specific immunoglobulin E (IgE) levels were significantly lower in the unheated yuzu seed oil group. Oral ingestion of yuzu seed oil in NC/Nga AD model mice significantly suppressed dermatitis deterioration and decreased serum IgE levels. Clinical trials (n = 41) have already confirmed that unheated yuzu oil is safe for long-term intake, further suggesting its potential use in improving AD symptoms.

Dermatophagoides farinae microRNAs released to external environments via exosomes regulate inflammation-related gene expression in human bronchial epithelial cells.

Background: Dermatophagoides farinae (DFA) is an important species of house dust mites (HDMs) that causes allergic diseases. Previous studies have focused on allergens with protein components to explain the allergic effect of HDMs; however, there is little knowledge on the role of microRNAs (miRNAs) in the allergic effect of HDMs. This study aimed to unravel the new mechanism of dust mite sensitization from the perspective of cross-species transport of extracellular vesicles-encapsulated miRNAs from HDMs. Methods: Small RNA (sRNA) sequencing was performed to detect miRNAs expression profiles from DFA, DFA-derived exosomes and DFA culture supernatants. A quantitative fluorescent real-time PCR (qPCR) assay was used to detect miRNAs expression in dust specimens. BEAS-2B cells endocytosed exosomes were modeled in vitro to detect miRNAs from DFA and the expression of related inflammatory factors. Representative dfa-miR-276-3p and dfa-novel-miR2 were transfected into BEAS-2B cells, and then differentially expressed genes (DEGs) were analyzed by RNA sequencing. Protein-protein interaction (PPI) network analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway and Gene Ontology (GO) terms enrichment analyses were performed on the first 300 nodes of DEGs. Results: sRNA sequencing identified 42 conserved miRNAs and 66 novel miRNAs in DFA, DFA-derived exosomes, and DFA culture supernatants. A homology analysis was performed on the top 18 conserved miRNAs with high expression levels. The presence of dust mites and miRNAs from HDMs in living environment were also validated. Following uptake of DFA-derived exosomes by BEAS-2B cells, exosomes transported miRNAs from DFA to target cells and produced pro-inflammatory effects in corresponding cells. RNA sequencing identified DEGs in dfa-miR-276-3p and dfa-novel-miR2 transfected BEAS-2B cells. GO and KEGG enrichment analyses revealed the role of exosomes with cross-species transporting of DFA miRNAs in inflammatory signaling pathways, such as JAK-STAT signaling pathway, PI3K/AKT signaling pathway and IL-6-mediated signaling pathway. Conclusion: Our findings demonstrate the miRNAs expression profiles in DFA for the first time. The DFA miRNAs are delivered into living environments via exosomes, and engulfed by human bronchial epithelial cells, and cross-species regulation may contribute to inflammation-related processes.

Seroprevalence of Dermatophagoides farinae-specific IgE in dogs with atopic dermatitis in São Paulo, Brazil.

Canine atopic dermatitis (CAD) is a chronic, inflammatory, and pruritic disease of the skin resulting from the loss of the epidermal barrier, sensitization, and exacerbated production of IgE antibodies mainly directed against environmental allergens, especially to house dust mites. To select specific allergen immunotherapies with high efficacy, there are necessary studies with house dust mite allergens to improve both serological and intradermal tests. Therefore, the objective of this study was to evaluate the seroprevalence of IgE against Der f 2, Zen 1, and crude Dermatophagoides farinae allergens in dogs with AD in the State of São Paulo, Brazil. The sera of 85 dogs with clinically confirmed atopic dermatitis from the State of São Paulo (Brazil) was collected. In addition, an indirect ELISA test was conducted to detect allergen-specific serum IgE. IgE seropositivity was observed in 97.5% of the dogs for Der f 2, 95.0% for Zen 1, and 92.5% for the crude mite allergens. Due to this high prevalence of IgE specific to these allergens, we suggest that Der f 2 and Zen 1 can be considered major allergens for dogs in the State of São Paulo.

Effects of low concentrations of ozone gas exposure on percutaneous oxygen saturation and inflammatory responses in a mouse model of Dermatophagoides farinae-induced asthma.

Ozone gas is widely used in hospitals as well as homes to control COVID-19 infection owing to its cost-effectiveness. Safety standard value and the tolerable value of ozone gas are set at 0.05 ppm and 0.1 ppm, respectively, in developed countries; however, this value was principally determined for healthy individuals, and the risks associated with ozone gas inhalation in patients with pulmonary diseases remains unknown. Recently, we demonstrated that 0.1 ppm ozone gas exposure significantly aggravates the symptoms of acute lung injury in mice. In the present study, we further examined the influence of ≤ 0.1 ppm ozone gas exposure on percutaneous oxygen saturation (SpO2) and pro-inflammatory responses in a mouse model of asthma. Female BALB/c mice were subjected to repetitive intranasal sensitization of Dermatophagoides farinae to generate a mouse model of asthma. Inhalation exposure of ozone gas (0.1, 0.03, 0.01 ppm), generated using an ultraviolet lamp, was performed for five consecutive days immediately before the final sacrifice. There were no abnormal findings in control mice exposed to 0.1 ppm ozone; however, 0.1 ppm ozone exposure significantly reduced the SpO2 level in asthmatic mice. Histological evaluation and gene expression analysis revealed that pro-inflammatory cytokine levels were significantly increased in mice exposed to 0.1 ppm ozone, indicating that 0.1 ppm ozone exposure affects the development of asthma symptoms. Notably, 0.03 and 0.01 ppm ozone exposure did not have any effects even in asthmatic mice. Our findings indicate that the tolerable level of ozone gas should be adjusted for individuals based on a history of respiratory disorders.

[Dermatophagoides farinae induces conjunctival epithelial cell damage to promote neutrophil migration and neutrophil extracellular traps formation].

OBJECTIVE: To investigate the mechanisms underlying allergic conjunctivitis caused by conjunctival epithelial cell damage, neutrophil migration and neutrophil extracellular traps (NETs) formation induced by crude extracts of Dermatophagoides farinae mite (CDM). METHODS: Human conjunctival epithelial cells were stimulated with 500, 1 000, 2 000, 4 000 ng/mL, and the expression levels of interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), interferon-γ (IFN-γ) and IL-8 were detected using quantitative real-time PCR (qPCR) assay and enzyme-linked immunosorbent assay (ELISA). The culture supernatant of human conjunctival epithelial cells was collected and co-cultured with neutrophils. Neutrophil migration was measured using Transwell migration assay, and the expression of NETs markers myeloperoxidase (MPO) and citrullinated histone H3 (CitH3) was quantified using immunofluorescence staining. Neutrophils were stimulated with phorbol 12-myristate 13-acetate (PMA), and then NETs were collected for treatment of human conjunctival epithelial cells. Cell apoptosis was detected using flow cytometry, and the levels of IL-6, TNF-α, IFN-γ and IL-8 were measured in the cell culture supernatant using ELISA. RESULTS: Treatment with CDM at concentrations of 2 000 ng/mL and 4 000 ng/mL up-regulated IL-6, TNF-α, IFN-γ and IL-8 expression in human conjunctival epithelial cells. Following treatment with CDM at concentrations of 2 000 ng/mL and 4 000 ng/mL, the culture supernatant of human conjunctival epithelial cells promoted neutrophil migration and induced increases in the staining intensity of MPO and CitH3. In addition, increased NETs triggered the apoptosis of human conjunctival epithelial cells and IL-6, TNF-α, IFN-γ and IL-8 secretion in the culture supernatant of human conjunctival epithelial cells. CONCLUSIONS: CDM induces human conjunctival epithelial cell damages, thereby promoting neutrophil migration and NETs formation, while the release of NETs further aggravates human conjunctival epithelial cell damages.

Rapid visual detection of the allergen Dermatophagoides farinae in house dust by loop-mediated isothermal amplification.

Dermatophagoides farinae is considered to be an important factor causing some allergic diseases, such as urticaria, allergic rhinitis, asthma, and other interrelated diseases. Avoiding exposure to allergens is the most effective way to reduce allergic reactions. In this study, we successfully established a loop-mediated isothermal amplification (LAMP) method for the detection of D. farinae DNA target internal transcribed spacer (ITS) and D. farinae 1 allergen (Der f 1) genes. The turbidity-monitoring system and visual fluorescent reagents were used to verify the test results of LAMP assay. Following optimization of the primers and reaction temperatures, the amplification sensitivity, specificity, and efficiency of the method for detecting D. farinae were assessed. There was no cross-reaction with other arthropod species that are commonly found in indoor environmental dust, such as Dermatophagoides pteronyssinus, Alophagoides ovatus, Periplaneta americana, Anopheles sinensis, and Musca domestica. Furthermore, the sensitivity of LAMP assay for detecting D. farinae DNA was 10 times greater than that of conventional PCR. The positive detection rate by the LAMP method was greater than the conventional PCR for both single D. farinae mites and D. farinae mites in indoor dust. A new type of LAMP method for D. farinae based on the Der f 1 and ITS genes was, therefore, successfully established. This study is the first time to detect the D. farinae allergen using LAMP assay. This assay could be useful as a model for the rapid detection of allergens produced by other house dust mites in the future.

Exosomes Derived from Dermatophagoides farinae Induce Allergic Airway Inflammation.

House dust mites (HDMs) are a major source of indoor allergens that cause airway allergic disease. Dermatophagoides farinae, a predominant species of HDMs in China, has demonstrated pathogenic role in allergic disorders. Exosomes derived from human bronchoalveolar lavage fluid have been strongly associated with allergic respiratory diseases progression. However, the pathogenic role of D. farinae-derived exosomes in allergic airway inflammation has remained unclear until now. Here, D. farinae was stirred overnight in phosphate-buffered saline, and the supernatant was used to extract exosomes by ultracentrifugation. Then, shotgun liquid chromatography-tandem mass spectrometry and small RNA sequencing were performed to identify proteins and microRNAs contained in D. farinae exosomes. Immunoblotting, Western blotting, and enzyme-linked immunosorbent assay demonstrated the specific immunoreactivity of D. farinae-specific serum IgE antibody against D. farinae exosomes, and D. farinae exosomes were found to induce allergic airway inflammation in a mouse model. In addition, D. farinae exosomes invaded 16-HBE bronchial epithelial cells and NR8383 alveolar macrophages to release the inflammation-related cytokines interleukin-33 (IL-33), thymic stromal lymphopoietin, tumor necrosis factor alpha, and IL-6, and comparative transcriptomic analysis of 16-HBE and NR8383 cells revealed that immune pathways and immune cytokines/chemokines were involved in the sensitization of D. farinae exosomes. Taken together, our data demonstrate that D. farinae exosomes are immunogenic and may induce allergic airway inflammation via bronchial epithelial cells and alveolar macrophages. IMPORTANCE Dermatophagoides farinae, a predominant species of house dust mites in China, has displayed pathogenic role in allergic disorders, and exosomes derived from human bronchoalveolar lavage fluid have been strongly associated with allergic respiratory diseases progression. However, the pathogenic role of D. farinae-derived exosomes in allergic airway inflammation has remained unclear until now. This study, for the first time, extracted exosomes from D. farinae, and sequenced their protein cargo and microRNAs using shotgun liquid chromatography-tandem mass spectrometry and small RNA sequencing. D. farinae-derived exosomes trigger allergen-specific immune responses and present satisfactory immunogenicity, as revealed by immunoblotting, Western blotting, and enzyme-linked immunosorbent assay and may induce allergic airway inflammation via bronchial epithelial cells and alveolar macrophages. Our data provide insights into the mechanisms of allergic airway inflammation caused with D. farinae-derived exosomes and the treatment of house dust mite-induced allergic airway inflammation.

Frequent IgE recognition of Blomia tropicalis allergen molecules in asthmatic children and young adults in equatorial Africa.

Background: Asthma is not well investigated in equatorial Africa and little is known about the disease-associated allergen molecules recognized by IgE from patients in this area. The aim was to study the molecular IgE sensitization profile of asthmatic children and young adults in a semi-rural area (Lambaréné) of an equatorial African country (Gabon), to identify the most important allergen molecules associated with allergic asthma in equatorial Africa. Methods: Fifty-nine asthmatic patients, mainly children and few young adults, were studied by skin prick testing to Dermatophagoides pteronyssinus (Der p), D. farinae (Der f), cat, dog, cockroach, grass, Alternaria and peanut. Sera were obtained from a subset of 35 patients, 32 with positive and 3 with negative skin reaction to Der p and tested for IgE reactivity to 176 allergen molecules from different allergen sources by ImmunoCAP ISAC microarray technology and to seven recombinant Blomia tropicalis (Blo t) allergens by IgE dot blot assay. Results: Thirty-three of the 59 patients (56%) were sensitized to Der p and 23 of them (39%) were also sensitized to other allergen sources, whereas 9 patients (15%) were only sensitized to allergen sources other than Der p. IgE serology analyses (n=35) showed high IgE-binding frequencies to the Blo t allergens Blo t 5 (43%), Blo t 21 (43%) and Blo t 2 (40%), whereas the Der p allergens rDer p 2, rDer p 21 and rDer p 5 (34%, 29% and 26%) were less frequently recognized. Only few patients showed IgE reactivity to allergens from other allergen sources, except to allergens containing carbohydrate determinants (CCDs) or to wasp venom allergens (i.e., antigen 5). Conclusion: Our results thus demonstrate that IgE sensitization to mite allergens is very prevalent in asthmatics in Equatorial Africa with B. tropicalis allergen molecules representing the most important ones associated with allergic asthma.

Site-specific tyrosine nitration of group 1 allergens of house dust mite Dermatophagoides farinae (Der f 1) and Dermatophagoides pteronyssinus (Der p 1) in indoor dusts.

Nitration can enhance the allergenicity of proteins. The nitration status of house dust mite (HDM) allergens in indoor dusts, however, remains to be elucidated. In the study, site-specific tyrosine nitration degrees of the two important HDM allergens Der f 1 and Der p 1 in indoor dust samples were investigated by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). The measured concentrations of native and nitrated allergens in the dusts were in the range of 0.86-29 µg g-1 for Der f 1 and from below the detection limit to 29 µg g-1 for Der p 1. Site-specific analysis revealed that all ten tyrosine residues in Der f 1 and Der p 1 were nitrated to different degrees in the investigated samples. The preferred nitration sites were Y56 in Der f 1 and Y37 in Der p 1 with the nitration degrees of 7.6-84% and 17-96% among the detected tyrosine residues, respectively. The measurements reveal high site-specific nitration degrees for tyrosine in Der f 1 and Der p 1 detected in the indoor dust samples. Further investigations are required to find out if the nitration really aggravates the health effects of HDM allergens and if the effects are tyrosine site-dependent.

Production of Dermatophagoides farinae Having Low Bacterial Content Using Ampicillin.

Background: Symbiotic bacteria in house dust mites pose a risk of immunological side effects in the clinical use of immunotherapeutic agents. In this study, we investigated the duration for which the bacterial concentration in Dermatophagoides farinae could be kept low with antibiotic treatment, and whether the allergenic properties of the mite changed under ampicillin treatment. Methods: D. farinae was cultivated in the presence of ampicillin powder in an autoclaved medium for 6 weeks. After subsequent subcultures without ampicillin, the mites were harvested, and the extract was prepared. The amounts of bacteria, lipopolysaccharides (LPS), and two major allergens (Der f 1 and Der f 2) were measured. Human bronchial epithelial cells and mice were treated with the D. farinae extract to assess the allergic airway inflammation. Results: The number of bacteria and level of LPS were reduced by 150-fold and 33-fold, respectively, at least 18 weeks after ampicillin treatment. The concentration of Der f 1 and Der f 2 remained unchanged by ampicillin treatment. The secretion of interleukin (IL)-6 and IL-8 from the human airway epithelial cells decreased when treated with the extract of ampicillin-treated D. farinae compared with that of ampicillin-untreated D. farinae. A mouse asthma model was developed using ampicillin-treated D. farinae. We observed that the level of lung function, airway inflammation, and serum-specific immunoglobulin were not different for the mouse asthma model developed using ampicillin-treated D. farinae than the model developed using ampicillin-untreated D. farinae. Conclusions: We showed that bacterial content in D. farinae was reduced by ampicillin treatment, which was sufficient to induce allergic sensitization and an immune response. This method will be used to develop more controlled allergy immunotherapeutic agents.

Lupeol alleviates atopic dermatitis-like skin inflammation in 2,4-dinitrochlorobenzene/Dermatophagoides farinae extract-induced mice.

BACKGROUND: Atopic dermatitis (AD) is a chronic inflammatory skin disease that affects from children to adults widely, presenting symptoms such as pruritus, erythema, scaling, and dryness. Lupeol, a pentacyclic triterpenoid, has anti-inflammatory and antimicrobial activities. Based on these properties, the therapeutic effects of lupeol on skin disorders have been actively studied. In the present study, we aimed to determine the effectiveness of lupeol on AD. METHODS: We utilized tumor necrosis factor (TNF)-α/interferon (IFN)-γ-stimulated keratinocytes and 2, 4-dinitrochlorobenzene/Dermatophagoides farinae extract (DFE)-induced AD mice to confirm the action. RESULTS: Lupeol inhibited TNF-α/IFN-γ-stimulated keratinocytes activation by reducing the expressions of pro-inflammatory cytokines and chemokines which are mediated by the activation of signaling molecules such as signal transducer and activator of transcription 1, mitogen-activated protein kinases (p38 and ERK), and nuclear factor-κB. Oral administration of lupeol suppressed epidermal and dermal thickening and immune cell infiltration in ear tissue. Immunoglobulin (Ig) E (total and DFE-specific) and IgG2a levels in serum were also reduced by lupeol. The gene expression and protein secretion of T helper (Th) 2 cytokines, Th1 cytokines, and pro-inflammatory cytokine in ear tissue were decreased by lupeol. CONCLUSIONS: These results suggest that lupeol has inhibitory effects on AD-related responses. Therefore, lupeol could be a promising therapeutic agent for AD.

Endogenous Plasmids and Chromosomal Genome Reduction in the Cardinium Endosymbiont of Dermatophagoides farinae.

Cardinium bacteria are well known as endosymbionts that infect a wide range of arthropods and can manipulate host reproduction to promote their vertical transmission. As intracellular bacteria, Cardinium species undergo dramatic genome evolution, especially their chromosomal genome reduction. Although Cardinium plasmids have been reported to harbor important genes, the role of these plasmids in the genome evolution is yet to be fully understood. In this study, 2 genomes of Cardinium endosymbiont bacteria in astigmatic mites were de novo assembled, including the complete circular chromosomal genome of Cardinium sp. DF that was constructed in high quality using high-coverage long-read sequencing data. Intriguingly, 2 circular plasmids were assembled in Cardinium sp. DF and were identified to be endogenous for over 10 homologous genes shared with the chromosomal genome. Comparative genomics analysis illustrated an outline of the genome evolution of Cardinium bacteria, and the in-depth analysis of Cardinium sp. DF shed light on the multiple roles of endogenous plasmids in the molecular process of the chromosomal genome reduction. The endogenous plasmids of Cardinium sp. DF not only harbor massive homologous sequences that enable homologous recombination with the chromosome, but also can provide necessary functional proteins when the coding genes decayed in the chromosomal genome. IMPORTANCE As bacterial endosymbionts, Cardinium typically undergoes genome reduction, but the molecular process is still unclear, such as how plasmids get involved in chromosome reduction. Here, we de novo assembled 2 genomes of Cardinium in astigmatic mites, especially the chromosome of Cardinium sp. DF was assembled in a complete circular DNA using high-coverage long-read sequencing data. In the genome assembly of Cardinium sp. DF, 2 circular endogenous plasmids were identified to share at least 10 homologous genes with the chromosomal genome. In the comparative analysis, we identified a range of genes decayed in the chromosomal genome of Cardinium sp. DF but preserved in the 2 plasmids. Taken together with in-depth analyses, our results unveil that the endogenous plasmids harbor homologous sequences of chromosomal genome and can provide a structural basis of homologous recombination. Overall, this study reveals that endogenous plasmids participate in the ongoing chromosomal genome reduction of Cardinium sp. DF.

Dermatophagoides farinae Extract Induces Interleukin 33-Mediated Atopic Skin Inflammation via Activation of RIP1.

Receptor-interacting protein kinase (RIP) family 1 signaling has complex effects on inflammatory processes and cell death, but little is known concerning allergic skin diseases. We examined the role of RIP1 in Dermatophagoides farinae extract (DFE)-induced atopic dermatitis (AD)-like skin inflammation. RIP1 phosphorylation was increased in HKCs treated with DFE. Nectostatin-1, a selective and potent allosteric inhibitor of RIP1, inhibited AD-like skin inflammation and the expression of histamine, total IgE, DFE-specific IgE, IL-4, IL-5, and IL-13 in an AD-like mouse model. The expression of RIP1 was increased in ear skin tissue from a DFE-induced mouse model with AD-like skin lesions and in the lesional skin of AD patients with high house dust mite sensitization. The expression of IL-33 was down-regulated after RIP1 inhibition, and the levels of IL-33 were increased by over-expression of RIP1 in keratinocytes stimulated with DFE. Nectostatin-1 reduced IL-33 expression in vitro and in the DFE-induced mouse model. These results suggest that RIP1 can be one of the mediators that regulate IL-33-mediated atopic skin inflammation by house dust mites.

Population growth and respiration in the dust mite Dermatophagoides farinae under different temperature and humidity regimes.

Dermatophagoides farinae is an important house dust mite species that causes allergies in humans worldwide. In houses, these mites are commonly found in actively used mattresses and pillows, which provide food (i.e. sloughed skin and microorganisms), moisture, and increased temperature for faster mite development. In mattresses, feeding mites prefer the upper sector, as close as possible to the resting human (temperature 32-36 °C, humidity between 55 and 59%). However, mites that are not actively feeding prefer staying at deeper zones of the mattress. Here, we analyzed mite responses to different temperatures (15-35 °C) and relative humidity (62-94% RH) in terms of their population size growth and respiration (CO2 production) using lab mite cultures. The intrinsic rate of population increase had a single maximum at approximately 28 °C and 85% RH. At 30 °C, there were two respiration peaks at RH 90% (smaller peak) and 65% (larger peak). Therefore, there is a mismatch between the optimal temperature/humidity for the population size increase vs. respiration. We propose preliminary hypotheses explaining the two respiration peaks and suggest that future research should be done to elucidate the nature of these peaks.

Lack of Interference of Oclacitinib with the results of intradermal testing or allergen-specific IgE serology in Dermatophagoides farinae-sensitized beagle dogs.

Canine atopic dermatitis (AD) is associated with increased levels of allergen-specific IgE due to hyper-sensitization to environmental allergens. Intradermal testing (IDT) and allergen-specific IgE serology testing are often used to determine the allergens which elicit an IgE response in animals with a diagnosis of AD. The objective of this study was to determine the effects of oclacitinib on IDT and allergen-specific IgE serology testing using a laboratory model of house-dust mite sensitized Beagle dogs. Twenty-four (24) normal, healthy purpose-bred Beagle dogs were sensitized to house dust mites (HDM, Dermatophagoides farinae) and randomly assigned to placebo-, oclacitinib- (0.4 mg/kg/dose PO), or prednisolone-treated (0.5 mg/kg/dose PO) groups. After 14 days of twice daily dosing, the effects of prednisolone and oclacitinib were compared to placebo using baseline and post-dose IDT and allergen-specific IgE serum measurements. Sensitized dogs had increased circulating HDM-specific IgE for at least two weeks post-sensitization. Prednisolone significantly inhibited the measurable sensitivity of IDT, while oclacitinib did not. Neither prednisolone nor oclacitinib imposed significant effects on allergen-specific IgE serum levels, suggesting oclacitinib may have potential to be used in dogs concurrently undergoing intradermal skin testing and/or allergen-specific IgE serology testing without interference with test results.

Dermatophagoides farinae induces conjunctival epithelial cell damage to promote neutrophil migration and neutrophil extracellular traps formation / 中国血吸虫病防治杂志

OBJECTIVE@#To investigate the mechanisms underlying allergic conjunctivitis caused by conjunctival epithelial cell damage, neutrophil migration and neutrophil extracellular traps (NETs) formation induced by crude extracts of Dermatophagoides farinae mite (CDM).@*METHODS@#Human conjunctival epithelial cells were stimulated with 500, 1 000, 2 000, 4 000 ng/mL, and the expression levels of interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), interferon-γ (IFN-γ) and IL-8 were detected using quantitative real-time PCR (qPCR) assay and enzyme-linked immunosorbent assay (ELISA). The culture supernatant of human conjunctival epithelial cells was collected and co-cultured with neutrophils. Neutrophil migration was measured using Transwell migration assay, and the expression of NETs markers myeloperoxidase (MPO) and citrullinated histone H3 (CitH3) was quantified using immunofluorescence staining. Neutrophils were stimulated with phorbol 12-myristate 13-acetate (PMA), and then NETs were collected for treatment of human conjunctival epithelial cells. Cell apoptosis was detected using flow cytometry, and the levels of IL-6, TNF-α, IFN-γ and IL-8 were measured in the cell culture supernatant using ELISA.@*RESULTS@#Treatment with CDM at concentrations of 2 000 ng/mL and 4 000 ng/mL up-regulated IL-6, TNF-α, IFN-γ and IL-8 expression in human conjunctival epithelial cells. Following treatment with CDM at concentrations of 2 000 ng/mL and 4 000 ng/mL, the culture supernatant of human conjunctival epithelial cells promoted neutrophil migration and induced increases in the staining intensity of MPO and CitH3. In addition, increased NETs triggered the apoptosis of human conjunctival epithelial cells and IL-6, TNF-α, IFN-γ and IL-8 secretion in the culture supernatant of human conjunctival epithelial cells.@*CONCLUSIONS@#CDM induces human conjunctival epithelial cell damages, thereby promoting neutrophil migration and NETs formation, while the release of NETs further aggravates human conjunctival epithelial cell damages.

[Scanning electron microscopic observation of the external morphology of Dermatophagoides farinae at different developmental stages].

OBJECTIVE: To investigate the morphological characteristics of Dermatophagoides farinae at different developmental stages. METHODS: The cultured D. farinae was isolated, and the external morphological features of mites at various developmental stages were observed using scanning electron microscopy (SEM), including egg, larva, nymph and adult stages. RESULTS: The D. farinae egg appeared a long oval shape, and the larval mites had three pairs of legs. The nymph had four pairs of legs and underdeveloped genital pores containing genital setae and anal setae, and adult mites appeared long and oval in shape, with decorative patterns on epidermis, and had four pairs of legs. In male adult mites, remarkable thickening of the leg I and thicker and longer leg III than the leg IV were seen, and ventral genital regions were found between the basal segments of legs III and IV; the anus was surrounded by a circular peri-anal ring, with a pair of anal suckers and anal setae within the ring. In the female adult mites, slender legs III and IV with an equal length were seen, and a "λ-shape" genital hole was observed on the ventral surface, with a crescent-like genital plate in the anterior part, and the anus appeared a longitudinal slit. CONCLUSIONS: An SEM observation of the external morphology of D. farinae provides understandings of the morphological characteristics of D. farinae, which is of great significance for the classification and identification.

Metabolomics analysis reveals molecular linkages for the impact of vitamin D on childhood allergic airway diseases.

BACKGROUND: Several studies have reported the relevance between serum vitamin D and allergic immunoglobulin E (IgE) responses and atopic diseases. However, a metabolomics-based approach to the impacts of vitamin D on allergic reactions remains unclear. METHODS: A total of 111 children completed a 3-year follow-up were enrolled and classified based on longitudinal vitamin D status (≥ 30 ng/ml, n = 54; 20-29.9 ng/ml, n = 41; <20 ng/ml, n = 16). Urinary metabolomic profiling was performed using 1 H-Nuclear magnetic resonance (NMR) spectroscopy at age 3. Integrative analyses of their associations related to vitamin D levels, atopic indices, and allergies were performed, and their roles in functional metabolic pathways were also assessed. RESULTS: Six and five metabolites were identified to be significantly associated with vitamin D status and atopic diseases, respectively (FDR-adjusted p-value <.05). A further correlation analysis revealed that vitamin D-associated 3-hydroxyisobutyric acid and glutamine were positively correlated with atopic disease-associated succinic acid and alanine, respectively. Furthermore, hippuric acid was negatively correlated with atopic disease-associated formic acid, which was positively correlated with vitamin D level (p < .01). Absolute eosinophil count (AEC) was positively correlated with serum D. pteronyssinus- and D. farinae-specific IgE level (p < .01) but negatively correlated with vitamin D level (p < .05). Amino acid metabolisms were significantly associated with vitamin D related to childhood allergies. CONCLUSION: Integrative metabolomic analysis provides the link of vitamin D-associated metabolites with the gut microbiome and immunoallergic reactions related to childhood allergies.

Risk factors for asthma in patients with allergic rhinitis in eastern China.

BACKGROUND: Asthma is one of the most common chronic diseases among children and adults and can lead to a high health and socioeconomic burden. Allergic rhinitis (AR) often precedes the development of asthma. This study aims to clarify the risk factors for cocurrent asthma in patients with AR in eastern China. METHODS: A cross-sectional study of 3739 patients with AR was performed in eastern China. Patients meeting the criteria for AR were evaluated using a skin-prick test (SPT) of 16 common aeroallergens. A logistic regression analysis was used to assess the risk factors of asthma in patients with AR. RESULTS: The prevalence of asthma in patients with AR was 14.23%. The patients sensitive to dust mites (D. farinae and D. pteronyssinus) had the highest prevalence (76.84% and 73.68%). A significant difference was found in sensitization to four types of allergens (D. farinae, D. pteronyssinus, dog dander, Alternaria alternata) in patients with AR with and without asthma. The strongest risk factor for asthma in patients with AR was an allergy to Aspergillus fumigatus (adjusted OR, 2.42; 95% CI, 1.50-3.90), followed by allergy to D. pteronyssinus (adjusted OR, 2.06; 1.30-3.27), and allergy to dog dander (adjusted OR, 1.92; 1.24-2.97). Various risk factors that are independently associated with asthma in patients with AR were found in different age groups. CONCLUSIONS: We observed a difference in risk factors in patients with AR with and without asthma. Clarifying the risk factors for asthma in patients with AR is important and may be beneficial to the optimal interventions of asthma.