Single-Cell RNA Sequencing of the T Helper Cell Response to House Dust Mites Defines a Distinct Gene Expression Signature in Airway Th2 Cells.

Naive CD4+ T cells differentiate into functionally diverse T helper (Th) cell subsets. Th2 cells play a pathogenic role in asthma, yet a clear picture of their transcriptional profile is lacking. We performed single-cell RNA sequencing (scRNA-seq) of T helper cells from lymph node, lung, and airways in the house dust mite (HDM) model of allergic airway disease. scRNA-seq resolved transcriptional profiles of naive CD4+ T, Th1, Th2, regulatory T (Treg) cells, and a CD4+ T cell population responsive to type I interferons. Th2 cells in the airways were enriched for transcription of many genes, including Cd200r1, Il6, Plac8, and Igfbp7, and their mRNA profile was supported by analysis of chromatin accessibility and flow cytometry. Pathways associated with lipid metabolism were enriched in Th2 cells, and experiments with inhibitors of key metabolic pathways supported roles for glucose and lipid metabolism. These findings provide insight into the differentiation of pathogenic Th2 cells in the context of allergy.

Impaired Tumor-Necrosis-Factor-α-driven Dendritic Cell Activation Limits Lipopolysaccharide-Induced Protection from Allergic Inflammation in Infants.

Infants have a higher risk of developing allergic asthma than adults. However, the underlying mechanism remains unknown. We show here that sensitization of mice with house-dust mites (HDMs) in the presence of low-dose lipopolysaccharide (LPS) prevented T helper 2 (Th2) cell allergic responses in adult, but not infant, mice. Mechanistically, adult CD11b+ migratory dendritic cells (mDCs) upregulated the transcription factor T-bet in response to tumor necrosis factor-α (TNF-α), which was rapidly induced after HDM + LPS sensitization. Consequently, adult CD11b+ mDCs produced interleukin-12 (IL-12), which prevented Th2 cell development by promoting T-bet upregulation in responding T cells. Conversely, infants failed to induce TNF-α after HDM + LPS sensitization. Therefore, CD11b+ mDCs failed to upregulate T-bet and did not secrete IL-12 and Th2 cell responses normally developed in infant mice. Thus, the availability of TNF-α dictates the ability of CD11b+ mDCs to suppress allergic Th2-cell responses upon dose-dependent endotoxin sensitization and is a key mediator governing susceptibility to allergic airway inflammation in infant mice.

The Allergen Der p3 from House Dust Mite Stimulates Store-Operated Ca2+ Channels and Mast Cell Migration through PAR4 Receptors.

The house dust mite is the principal source of perennial aeroallergens in man. How these allergens activate innate and adaptive immunity is unclear, and therefore, there are no therapies targeting mite allergens. Here, we show that house dust mite extract activates store-operated Ca2+ channels, a common signaling module in numerous cell types in the lung. Activation of channel pore-forming Orai1 subunits by mite extract requires gating by STIM1 proteins. Although mite extract stimulates both protease-activated receptor type 2 (PAR2) and PAR4 receptors, Ca2+ influx is more tightly coupled to the PAR4 pathway. We identify a major role for the serine protease allergen Der p3 in stimulating Orai1 channels and show that a therapy involving sub-maximal inhibition of both Der p3 and Orai1 channels suppresses mast cell activation to house dust mite. Our results reveal Der p3 as an important aeroallergen that activates Ca2+ channels and suggest a therapeutic strategy for treating mite-induced asthma.

The human MIF polymorphism CATT7 enhances pro-inflammatory macrophage polarization in a clinically relevant model of allergic airway inflammation.

High level expression of the pro-inflammatory cytokine macrophage migration inhibitory factor (MIF) has been associated with severe asthma. The role of MIF and its functional promotor polymorphism in innate immune training is currently unknown. Using novel humanized CATT7 MIF mice, this study is the first to investigate the effect of MIF on bone marrow-derived macrophage (BMDM) memory after house dust mite (HDM) challenge. CATT7 BMDMs demonstrated a significant primed increase in M1 markers following HDM and LPS stimulation, compared to naive mice. This M1 signature was found to be MIF-dependent, as administration of a small molecule MIF inhibitor, SCD-19, blocked the induction of this pro-inflammatory M1-like phenotype in BMDMs from CATT7 mice challenged with HDM. Training naive BMDMs in vitro with HDM for 24 h followed by a rest period and subsequent stimulation with LPS led to significantly increased production of the pro-inflammatory cytokine TNFα in BMDMs from CATT7 mice but not WT mice. Addition of the pan methyltransferase inhibitor MTA before HDM training significantly abrogated this effect in BMDMs from CATT7 mice, suggesting that HDM-induced training is associated with epigenetic remodelling. These findings suggest that trained immunity induced by HDM is under genetic control, playing an important role in asthma patients with the high MIF genotypes (CATT6/7/8).

Perinatal Activation of the Interleukin-33 Pathway Promotes Type 2 Immunity in the Developing Lung.

Allergic disease originates in early life and polymorphisms in interleukin-33 gene (IL33) and IL1RL1, coding for IL-33R and decoy receptor sST2, confer allergy risk. Early life T helper 2 (Th2) cell skewing and allergy susceptibility are often seen as remnants of feto-maternal symbiosis. Here we report that shortly after birth, innate lymphoid type 2 cells (ILC2s), eosinophils, basophils, and mast cells spontaneously accumulated in developing lungs in an IL-33-dependent manner. During the phase of postnatal lung alveolarization, house dust mite exposure further increased IL-33, which boosted cytokine production in ILC2s and activated CD11b+ dendritic cells (DCs). IL-33 suppressed IL-12p35 and induced OX40L in neonatal DCs, thus promoting Th2 cell skewing. Decoy sST2 had a strong preventive effect on asthma in the neonatal period, less so in adulthood. Thus, enhanced neonatal Th2 cell skewing to inhaled allergens results from postnatal hyperactivity of the IL-33 axis during a period of maximal lung remodeling.

Structural analysis of human IgE monoclonal antibody epitopes on dust mite allergen Der p 2.

BACKGROUND: Human IgE (hIgE) mAbs against major mite allergen Der p 2 developed using human hybridoma technology were used for IgE epitope mapping and analysis of epitopes associated with the hIgE repertoire. OBJECTIVE: We sought to elucidate the new hIgE mAb 4C8 epitope on Der p 2 and compare it to the hIgE mAb 2F10 epitope in the context of the allergenic structure of Der p 2. METHODS: X-ray crystallography was used to determine the epitope of anti-Der p 2 hIgE mAb 4C8. Epitope mutants created by targeted mutagenesis were analyzed by immunoassays and in vivo using a human high-affinity IgE receptor (FcεRIα)-transgenic mouse model of passive systemic anaphylaxis. RESULTS: The structure of recombinant Der p 2 with hIgE mAb 4C8 Fab was determined at 3.05 Å. The newly identified epitope region does not overlap with the hIgE mAb 2F10 epitope or the region recognized by 3 overlapping hIgE mAbs (1B8, 5D10, and 2G1). Compared with wild-type Der p 2, single or double 4C8 and 2F10 epitope mutants bound less IgE antibodies from allergic patients by as much as 93%. Human FcεRIα-transgenic mice sensitized by hIgE mAbs, which were susceptible to anaphylaxis when challenged with wild-type Der p 2, could no longer cross-link FcεRI to induce anaphylaxis when challenged with the epitope mutants. CONCLUSIONS: These data establish the structural basis of allergenicity of 2 hIgE mAb nonoverlapping epitopes on Der p 2, which appear to make important contributions to the hIgE repertoire against Der p 2 and provide molecular targets for future design of allergy therapeutics.

Accurate determination of house dust mite sensitization in asthma and allergic rhinitis through cytometric detection of Der p 1 and Der p 2 binding on basophils (CytoBas).

BACKGROUND: House dust mite (HDM) is the most common allergen trigger globally for allergic rhinitis and atopic asthma. OBJECTIVES: To expedite accurate confirmation of allergen sensitization, we designed fluorescent allergen tetramers to directly stain specific IgE on basophils to detect specific allergen sensitization using the flow cytometric CytoBas assay. METHODS: Recombinant proteins of major HDM allergens (component), Der f 1, Der p 1, and Der p 2 were biotinylated and conjugated with fluorochrome streptavidins as tetramers. Blood samples from 64 patients who are HDM-allergic and 26 controls that are non-HDM-sensitized were incubated with allergen tetramers for evaluation of basophil binding (CytoBas) and activation (BAT) with flow cytometry. RESULTS: The tetramers effectively bound and activated basophils from patients who are allergic but not from controls who are nonsensitized. CytoBas with Der p 1 as a single allergen had comparable sensitivity and specificity (92% and 100%) to BAT (91% and 100%) in detecting allergen sensitization, as did CytoBas with Der p 2 (95% and 96%) to BAT (95% and 87%). A positive staining for Der p 1 and/or Der p 2 in CytoBas was 100% sensitive and 96% specific for HDM allergy. CONCLUSIONS: CytoBas has diagnostic accuracy for group 1 and group 2 HDM allergens that is comparable to BAT, but with additional advantages of multiple allergen components in a single tube and no requirement for in vitro basophil activation. These findings endorse a single, multiplex CytoBas assay for accurate and component-resolved diagnosis of aeroallergen sensitization in patients with allergic asthma and/or rhinitis.

MIF is essential to the establishment of house dust mite-induced airway inflammation and tissue remodeling in mice.

Macrophage migration inhibitory factor (MIF) is present in high amounts in the BALF and serum of asthmatic patients, contributing to the pathogenesis of experimental asthma induced by OVA in mice. Whether MIF contributes to the physiopathology on a more complex and relevant asthma model has not been characterized. Mif-deficient (Mif-/- ) or WT mice treated with anti-MIF antibody were challenged multiple times using house dust mite (HDM) extract by the intranasal route. HDM-challenged Mif-/- mice presented decreased airway hyperresponsiveness, lung infiltration of eosinophils, mucus hypersecretion, and subepithelial fibrosis compared to HDM-challenged WT mice. Amounts of IL-4, IL-5, and IL-13 were decreased in the lungs of Mif-/- mice upon HDM challenges, but the increase of CCL11 was preserved, compared to HDM-challenged WT mice. We also observed increased numbers of group 2 innate lymphoid cells and Th2 cells in the BALF and mediastinal LNs (mLN)-induced challenged by HDM of WT mice, but not in HDM-challenged Mif-/- mice. Anti-MIF treatment abrogated the airway infiltration of eosinophils, mucus hypersecretion, and subepithelial fibrosis in the lungs of HDM-challenged mice. In conclusion, MIF ablation prevents the pathologic hallmarks of asthma in HDM-challenged mice, reinforcing the promising target of MIF for asthma therapy.

Structural homology of mite profilins to plant profilins is not indicative of allergic cross-reactivity.

Structural and allergenic characterization of mite profilins has not been previously pursued to a similar extent as plant profilins. Here, we describe structures of profilins originating from Tyrophagus putrescentiae (registered allergen Tyr p 36.0101) and Dermatophagoides pteronyssinus (here termed Der p profilin), which are the first structures of profilins from Arachnida. Additionally, the thermal stabilities of mite and plant profilins are compared, suggesting that the high number of cysteine residues in mite profilins may play a role in their increased stability. We also examine the cross-reactivity of plant and mite profilins as well as investigate the relevance of these profilins in mite inhalant allergy. Despite their high structural similarity to other profilins, mite profilins have low sequence identity with plant and human profilins. Subsequently, these mite profilins most likely do not display cross-reactivity with plant profilins. At the same time the profilins have highly conserved poly(l-proline) and actin binding sites.

Tolerability of sublingual versus vestibular allergy immunotherapy tablet administration: A randomized pilot study.

BACKGROUND: Local application site reactions are common with sublingual allergy immunotherapy (AIT)-tablets for the treatment of allergic rhinitis/conjunctivitis (AR/C) and occasionally lead to treatment discontinuation. Because of the lower mast cell density in the vestibular mucosa than the sublingual area, vestibular AIT-tablet administration may result in fewer adverse events (AEs). This pilot study evaluated the tolerability of the vestibular administration route of AIT-tablets compared with the sublingual route in adult subjects with AR/C. METHODS: Adults (n = 164) aged 18-65 years with AR/C treated with daily birch pollen, grass pollen, ragweed pollen or house dust mite AIT in tablet form were randomized 1:1 to vestibular or sublingual administration for 28 days, followed by 28 days of sublingual administration only. The primary endpoint was the severity (mild, moderate, severe) of local treatment-related adverse events (TRAEs) during the first 28 days of treatment. RESULTS: During the first 28 days, the percentage of subjects in the vestibular and sublingual groups reporting mild TRAEs were 55.6% versus 50.6%, respectively; moderate TRAEs were 27.2% versus 30.1%; and severe TRAEs were 12.3% versus 6.0% (p = .16). In the vestibular group, 95.1% of the subjects experienced at least one TRAE during the first period versus 81.9% in the sublingual group (p = .01) and discontinuation rates due to AEs were higher (12.3% vs. 3.6%). CONCLUSION: The frequencies of subjects experiencing severe TRAEs, at least one TRAE, and discontinuations due to AEs at the initiation of AIT-tablets were numerically higher with vestibular administration than sublingual administration. Sublingual administration should remain the standard of care for subjects treated with AIT-tablets for AR/C.

Efficacy of 300 IR house dust mite immunotherapy as a function of disease activity: Tertile analysis in clinical trials.

BACKGROUND: The symptoms of house dust mite (HDM)-induced allergic rhinitis (AR) vary with changes in exposure related to the weather or the domestic environment. In allergen immunotherapy (AIT) studies, a certain level of AR disease activity is necessary to demonstrate treatment efficacy; the latter can be underestimated if a substantial proportion of the patient population is weakly symptomatic. OBJECTIVE: To better estimate the real treatment effect of a HDM sublingual AIT (SLIT) tablet, we analysed the results of natural field studies in detail by applying a tertile approach. METHODS: We used data from three randomised, controlled trials (RCT) in a total of 2585 patients with AR treated with the 300 index of reactivity (IR) HDM SLIT-tablet or placebo. The study centres were grouped into tertiles according to the level of combined symptom and medication scores in patients in the placebo group. In each tertile, the difference between SLIT and placebo was assessed through an analysis of covariance. RESULTS: In the three RCTs, combined scores were found to be similar in the SLIT and placebo groups in the low tertiles. The treatment effect of the 300 IR HDM tablet increased in the medium and high tertiles, with notably significant differences versus placebo in the highest tertile and greater (ranging from -21% to -39%) than in the entire study population (-13% to -20%). The positive relationship between treatment efficacy and the combined score in each tertile was independent of the RCT and the score used. CONCLUSION AND CLINICAL RELEVANCE: Application of the tertile approach to AIT studies in a field in which many variables interact strongly might provide more accurate and meaningful measurements of efficacy and benefit for patients, better reflecting their real-life condition.

Mesenchymal stromal cells dampen trained immunity in house dust mite-primed macrophages expressing human macrophage migration inhibitory factor polymorphism.

BACKGROUND: Trained immunity results in long-term immunological memory, provoking a faster and greater immune response when innate immune cells encounter a secondary, often heterologous, stimulus. We have previously shown that house dust mite (HDM)-induced innate training is amplified in mice expressing the human macrophage migration inhibitory factor (MIF) CATT7 functional polymorphism. AIM: This study investigated the ability of mesenchymal stromal cells (MSCs) to modulate MIF-driven trained immunity both in vitro and in vivo. METHODS: Compared with wild-type mice, in vivo HDM-primed bone marrow-derived macrophages (BMDMs) from CATT7 mice expressed significantly higher levels of M1-associated genes following lipopolysaccharide stimulation ex vivo. Co-cultures of CATT7 BMDMs with MSCs suppressed this HDM-primed effect, with tumor necrosis factor alpha (TNF-α) being significantly decreased in a cyclooxygenase 2 (COX-2)-dependent manner. Interestingly, interleukin 6 (IL-6) was suppressed by MSCs independently of COX-2. In an in vitro training assay, MSCs significantly abrogated the enhanced production of pro-inflammatory cytokines by HDM-trained CATT7 BMDMs when co-cultured at the time of HDM stimulus on day 0, displaying their therapeutic efficacy in modulating an overzealous human MIF-dependent immune response. Utilizing an in vivo model of HDM-induced trained immunity, MSCs administered systemically on day 10 and day 11 suppressed this trained phenomenon by significantly reducing TNF-α and reducing IL-6 and C-C motif chemokine ligand 17 (CCL17) production. CONCLUSIONS: This novel study elucidates how MSCs can attenuate an MIF-driven, HDM-trained response in CATT7 mice in a model of allergic airway inflammation.

House dust mite SCIT reduces asthma risk and significantly improves long-term rhinitis and asthma control-A RWE study.

BACKGROUND: The German Therapy Allergen Ordinance (TAO) triggered an ongoing upheaval in the market for house dust mite (HDM) allergen immunotherapy (AIT) products. Three HDM subcutaneous AIT (SCIT) products hold approval in Germany and therefore will be available after the scheduled completion of the TAO procedure in 2026. In general, data from clinical trials on the long-term effectiveness of HDM AIT are rare. We evaluated real-world data (RWD) in a retrospective, observational cohort study based on a longitudinal claims database including 60% of all German statutory healthcare prescriptions to show the long-term effectiveness of one of these products in daily life. Aim of this analysis was to provide a per product analysis on effectiveness of mite AIT as it is demanded by international guidelines on AIT. METHODS: Subjects between 5 and 70 years receiving their first (index) prescription of SCIT with a native HDM product (SCIT group) between 2009 and 2013 were included. The exactly 3:1 matched control group received prescriptions for only symptomatic AR medication (non-AIT group); the evaluation period for up to 6 years of follow-up ended in February 2017. Study endpoints were the progression of allergic rhinitis (AR) and asthma, asthma occurrence and time to the onset of asthma after at least 2 treatment years. RESULTS: In total, 892 subjects (608 adults and 284 children/adolescents) were included in the SCIT group and 2676 subjects (1824 adults and 852 children/adolescents) in the non-AIT group. During the follow-up period after at least 2 years of SCIT, the number of prescriptions in the SCIT group was reduced by 62.8% (p < .0001) for AR medication and by 42.4% for asthma medication (p = .0003). New-onset asthma risk was significantly reduced in the SCIT vs non-AIT group by 27.0% (p = .0212). The asthma-preventive effect of SCIT occurred 15 months after start of the treatment. In the SCIT group, the time to onset of asthma was prolonged compared to the non-AIT group (p = .0010). CONCLUSION: In this first product based RWD analysis on SCIT with a native HDM product, patients aged 5 to 70 years benefited from AIT in the long term in terms of reduced progression of AR and asthma after at least 2 years of treatment. The effects seemed to last for up to 6 years after treatment termination. A significantly reduced risk of asthma onset was observed, starting after 15 months of treatment.

Blockade of MIF biological activity ameliorates house dust mite-induced allergic airway inflammation in humanized MIF mice.

Macrophage migration inhibitory factor (MIF) expression is controlled by a functional promoter polymorphism, where the number of tetranucleotide repeats (CATTn ) corresponds to the level of MIF expression. To examine the role of this polymorphism in a pre-clinical model of allergic asthma, novel humanized MIF mice with increasing CATT repeats (CATT5 and CATT7 ) were used to generate a physiologically relevant scale of airway inflammation following house dust mite (HDM) challenge. CATT7 mice expressing high levels of human MIF developed an aggressive asthma phenotype following HDM challenge with significantly elevated levels of immune cell infiltration, production of inflammatory mediators, goblet cell hyperplasia, subepithelial collagen deposition, and airway resistance compared to wild-type controls. Importantly the potent MIF inhibitor SCD-19 significantly mitigated the pathophysiology observed in CATT7 mice after HDM challenge, demonstrating the fundamental role of endogenous human MIF expression in the severity of airway inflammation in vivo. Up to now, there are limited reproducible in vivo models of asthma airway remodeling. Current asthma medications are focused on reducing the acute inflammatory response but have limited effects on airway remodeling. Here, we present a reproducible pre-clinical model that capitulates asthma airway remodeling and suggests that in addition to having pro-inflammatory effects MIF may play a role in driving airway remodeling.

Efficacy and safety of subcutaneous immunotherapy combined with omalizumab in children with dust mite-induced asthma.

OBJECTIVE: To evaluate the benefits of combining omalizumab with specific immunotherapy (SCIT) in the treatment of children with bronchial asthma. METHODS: In this study, 83 children with asthma were treated at the Allergy Department of Qingdao University from January 2019 to February 2020. Participants were divided into three groups: SCIT, combination (omalizumab + SCIT), and control (standard asthma medications). We assessed Asthma Control Questionnaire (ACQ) scores, Visual Analogue Scale (VAS) scores, and lung function at baseline, 24 wk, and 48 wk. Additionally, asthma medication scores were compared at 24 and 48 wk. Adverse reactions were monitored in both the SCIT and combination groups. RESULTS: The combination group demonstrated lower ACQ scores at both 24 and 48 wk, and improved VAS scores at 48 wk compared to the other groups. Additionally, lung function parameters (FEV1 and FEF50) showed significant improvement in the combination group. Reduced asthma medication scores were noted in the combination group at 24 and 48 wk. Local adverse reactions were fewer in the combination group, and no systemic adverse reactions were reported. CONCLUSION: Combining omalizumab with SCIT provides quicker asthma control, lowers medication requirements, and enhances lung function with fewer adverse effects, making it a safe and effective treatment for children with bronchial asthma.

Tropical high altitude and severe asthma in adults: house dust mite sensitization and phenotypic distribution.

BACKGROUND: There is a lack of information on house dust mite (HDM) sensitization and phenotype distribution in patients with severe asthma (SA) living permanently at high-altitude (HA) in tropical regions, which may be different. OBJECTIVE: The aim of this study was to characterize adults with SA in a tropical high altitude city (2,640 m): Bogotá, Colombia. MATERIAL AND METHODS: This observational cross-sectional study included severe asthmatic outpatients (n = 129) referred to the ASMAIRE program of the Fundación Neumológica Colombiana in Bogotá (2,640 m). Clinical history, spirometry, total IgE, blood eosinophils, and skin prick test (SPT), including HDM allergens, were performed. Phenotype definitions: Allergic/atopic (AA): IgE ≥100 IU/mL and/or at least one positive SPT; eosinophilic (EOS): blood eosinophils ≥300 cells/µL; type 2-high: AA and/or EOS phenotype; type 2-low: non-AA/non-EOS phenotype (IgE <100 IU/mL, negative SPT, and blood eosinophils <300 cells/µL). RESULTS: A total of 129 adults with SA were included, 79.8% female. Phenotype distribution: AA: 61.2%; EOS: 37.2%; type 2-high: 72.1%; type 2-low: 27.9%. Among AA patients, HDM sensitization was present in 87% and 34.9% were non-eosinophilic. There was a significant overlap between the phenotypes. CONCLUSIONS: In contrast to non-tropical high-altitude regions, we found a high frequency of HDM sensitization in patients with AA phenotype living in a tropical high-altitude city. We also found a discrete lower frequency of EOS phenotype with no other significant differences in the phenotypic distribution compared to that described at low altitudes. We propose that tropical location may modify the effect of high altitude on HDM concentrations and allergenicity.

House dust mite allergen Der f 2 drives IL-6 and GM-CSF expression in airway epithelial cells via p38 MAPK/NF-κB signaling.

OBJECTIVE: Der f 2, a major allergen derived from Dermatophagoides farinae, is a leading cause of allergic asthma. IL-6 and GM-CSF play essential roles in the exacerbation of asthma. However, the mechanical act by which Der f 2 mediates the expression of IL-6, IL-8, and GM-CSF in airway epithelial cells remains incompletely elucidated. Herein, we aimed to explore the effect of Der f 2 on IL-6 and GM-CSF expression in the human airway epithelial cell BEAS-2B and A549. METHODS: Recombinant Der f 2 (rDf2) was acquired using Pichia pastoris. BEAS-2B and A549 cells were used as cell model. The expression of genes and proteins and the involvement of the signaling cascade were assessed using RT-PCR, quantitative real-time PCR (qPCR), Western blotting, and ELISA, respectively. RESULTS: Our findings showed that rDf2 significantly induced mRNA expression and protein production of IL-6 and GM-CSF in BEAS-2B and A549 cells. In contrast, rDf2 did not influence IL-8 expression or production in both cells. Mechanistic studies revealed that rDf2 triggered activation of the p38 MAPK and JNK. Inhibition of p38, but not JNK, significantly attenuated rDf2-induced IL-6 and GM-CSF expression and production. CONCLUSION: This study demonstrates that Der f 2 promotes the expression and production of the pro-inflammatory cytokines IL-6 and GM-CSF in airway epithelial cells via activation of the p38 signaling pathway. These findings provide insights into the molecular mechanisms that Der f 2 may exacerbate airway inflammation.

Human macrophage migration inhibitory factor potentiates mesenchymal stromal cell efficacy in a clinically relevant model of allergic asthma.

Current asthma therapies focus on reducing symptoms but fail to restore existing structural damage. Mesenchymal stromal cell (MSC) administration can ameliorate airway inflammation and reverse airway remodeling. However, differences in patient disease microenvironments seem to influence MSC therapeutic effects. A polymorphic CATT tetranucleotide repeat at position 794 of the human macrophage migration inhibitory factor (hMIF) gene has been associated with increased susceptibility to and severity of asthma. We investigated the efficacy of human MSCs in high- vs. low-hMIF environments and the impact of MIF pre-licensing of MSCs using humanized MIF mice in a clinically relevant house dust mite (HDM) model of allergic asthma. MSCs significantly attenuated airway inflammation and airway remodeling in high-MIF-expressing CATT7 mice but not in CATT5 or wild-type littermates. Differences in efficacy were correlated with increased MSC retention in the lungs of CATT7 mice. MIF licensing potentiated MSC anti-inflammatory effects at a previously ineffective dose. Mechanistically, MIF binding to CD74 expressed on MSCs leads to upregulation of cyclooxygenase 2 (COX-2) expression. Blockade of CD74 or COX-2 function in MSCs prior to administration attenuated the efficacy of MIF-licensed MSCs in vivo. These findings suggest that MSC administration may be more efficacious in severe asthma patients with high MIF genotypes (CATT6/7/8).

Frequency of Euroglyphus maynei sensitization in respiratory allergies: a real-life study with bioinformatic analysis and geographical exploration of allergen prevalence.

BACKGROUND: Dermatophagoides pteronyssinus and Dermatophagoides farinae belong to the family Pyroglyphidae (subfamily: "Dermatophagoidinae") and have the respective allergenic proteins of Der p1, Der p2, and Der p23 and Der f1 and Der f2. Euroglyphus maynei, belongs to the family Pyroglyphidae (subfamily: "Pyroglyphinae") and its main allergenic protein is Eur m1, a source of sensitization. Sensitization to D. pteronyssinus and D. farinae is assessed through skin tests, while sensitization to E. maynei is assessed less frequently. OBJECTIVE: This experimental work aims to analyze the prevalence of sensitization to E. maynei in patients with respiratory allergies treated at M. Albanesi Allergy and Immunology Unit in Bari, Italy, and the sequence homology of major allergenic proteins of E. maynei with D. farinae and D. pteronyssinus was analyzed. METHODS: In this real-life study, 65 patients were enrolled. In particular, patients with respiratory allergy were subjected to skin prick tests for common respiratory allergens, including Euroglyphus maynei. The sequence homology analysis was performed between the major allergenic proteins of E. maynei and those of D. pteronyssinus and D. farinae. RESULTS: Sensitization to E. maynei accounts for 41.5% of patients. All patients with E. maynei sensitization had concomitant sensitization to D. farinae and D. pteronyssinus. The analysis of sequence homology of Der p1 and Der f1 proteins with the sequence of Eur m1 protein demonstrated an identity of 84.4% and 86%, respectively. CONCLUSIONS: Nearly 50% of house dust mites-sensitized patients have a concomitant sensitization to E. maynei. The cross-sensitization could be due to Der f1, Der p1, and Eur m1 similarity.

Short-term and long-term efficacy of sublingual immunotherapy in different courses for house dust mite-induced allergic rhinitis.

PURPOSE: Sublingual immunotherapy (SLIT) has been proven to be an effective and safe treatment for patients with house dust mite (HDM)-induced allergic rhinitis (AR) to achieve short-term and long-term efficacy. This study aimed to investigate the relationship between SLIT duration and long-term efficacy. MATERIALS AND METHODS: This study involved 134 patients who underwent SLIT between 2019 and 2021 (in the 2-year group), between 2018 and 2021(in the 3-year group), or between 2017 and 2021 (in the 4-year group). The total nasal symptoms score (TNSS), total medication score (TMS), visual analogue scale (VAS), the Mini Rhinoconjunctivitis Quality of Life Questionnaire (MiniRQLQ) and adverse events (AEs) were assessed at baseline, after treatment (2021) and one year after the treatment completion (2022). The correlation between MiniRQLQ and other indicators was also analyzed. RESULTS: After SLIT, patients in all three groups showed significant improvements in TNSS, TMS, VAS and MiniRQLQ scores (all p < 0.001). These improvements were sustained even one year after SLIT. Patients who received 3-4 years of SLIT showed significant improvement compared with those who received 2 years of SLIT in all clinical outcomes (all p < 0.01). The analysis showed positive correlations between the MiniRQLQ and TNSS, TMS, and VAS (all p < 0.001). No significant difference was observed in the AE rate in all three groups (p > 0.05). CONCLUSION: Different duration of HDM SLIT could generate various short-term and long-term clinical efficacy. The MiniRQLQ could be applied to evaluate SLIT efficacy in clinical practice.