Monitoring and stopping Hymenoptera venom immunotherapy: Contribution of IgE blocking activity.

Background: Hymenoptera venom allergy is a public health issue and has an undeniable impact on quality of life. Allergen immunotherapy (AIT) has shown long-term efficacy in this severe and potentially lethal allergy. However, no biomarker can predict the effectiveness of this treatment. Objectives: We evaluated the contribution of IgE blocking activity, a functional biomarker carried out in our center using flow cytometry, to predict the efficacy of AIT. Methods: This retrospective study from 1985 to 2022 describes in detail the demographic, clinical, and biological characteristics of patients who benefited from AIT with Hymenoptera venom at the University Hospital of Limoges. The outcome measure used was the presence of anaphylactic reaction (grade I to IV according to Ring and Messmer) in case of a new sting after discontinuation of AIT. Results: Our study, mainly composed of patients allergic to Vespula wasp venom, did not emphasize the interest of IgE blocking activity in the prediction of a relapse after a new sting. However, this inhibition showed a significant correlation with the amount of IgG4 antibodies. Conclusion: There is no biomarker that can help make the decision of stopping AIT. However, low levels of IgE blocking activity may suggest a likelihood of relapse. Serum IgG4, in correlation with IgE blocking activity, could be useful for monitoring treatment response. Additional studies are necessary to gain a thorough understanding of the composition of inhibitory antibodies.

Application of PLGA-PEG-PLGA Nanoparticles to Percutaneous Immunotherapy for Food Allergy.

Compared with oral or injection administration, percutaneous immunotherapy presents a promising treatment modality for food allergies, providing low invasiveness and safety. This study investigated the efficacy of percutaneous immunotherapy using hen egg lysozyme (HEL)-loaded PLGA-PEG-PLGA nanoparticles (NPs), as an antigen model protein derived from egg white, compared with that of HEL-loaded chitosan hydroxypropyltrimonium chloride (CS)-modified PLGA NPs used in previous research. The intradermal retention of HEL in excised mouse skin was measured using Franz cells, which revealed a 2.1-fold higher retention with PLGA-PEG-PLGA NPs than that with CS-modified PLGA NPs. Observation of skin penetration pathways using fluorescein-4-isothiocyanate (FITC)-labeled HEL demonstrated successful delivery of HEL deep into the hair follicles with PLGA-PEG-PLGA NPs. These findings suggest that after NPs delivery into the skin, PEG prevents protein adhesion and NPs aggregation, facilitating stable delivery deep into the skin. Subsequently, in vivo percutaneous administration experiments in mice, with concurrent iontophoresis, demonstrated a significant increase in serum IgG1 antibody production with PLGA-PEG-PLGA NPs compared with that with CS-PLGA NPs after eight weeks of administration. Furthermore, serum IgE production in each NP administration group significantly decreased compared with that by subcutaneous administration of HEL solution. These results suggest that the combination of PLGA-PEG-PLGA NPs and iontophoresis is an effective percutaneous immunotherapy for food allergies.

IL-10: the master immunomodulatory cytokine in allergen immunotherapy.

INTRODUCTION: Allergen immunotherapy (AIT) is the only disease-modifying treatment for patients with IgE-mediated allergic diseases. Successful AIT can induce long-term immune tolerance to the common allergen, which provides clinical benefits for years after discontinuation. The cytokine interleukin (IL)-10, as a key anti-inflammatory mediator with strong immunoregulatory functions, has drawn increasing attention over the past decades. AREAS COVERED: After an extensive search of PubMed, EMBASE, and Web of Science databases, covering articles published from 1989 to 2024, our review aims to emphasize the key common information from previous reviews on the crucial involvement of IL-10 in allergen immunotherapy (AIT) induced immunological tolerance. In this review, we discuss the regulation of IL-10 expression and the molecular pathways associated with IL-10 function. We also further summarize mechanisms of immune tolerance induced by AIT, especially the indispensable role of IL-10 in AIT. EXPERT OPINION: IL-10 plays an indispensable role in immune tolerance induced by AIT. Understanding the importance of the role of IL-10 in AIT would help us comprehend the mechanisms thoroughly and develop targeted therapeutics for allergic diseases.

Allergen immunotherapy effectiveness in specific nasal reactivity of children with local allergic rhinitis.

Summary: Background. Allergen immunotherapy (AIT) is the only disease-modifying treatment in allergy. Its efficacy has been demonstrated in the treatment of Local Allergic Rhinitis (LAR) in adults. This study intends to evaluate the effectiveness of AIT in specific nasal reactivity of paediatric patients with LAR. Methods. Patients diagnosed with LAR to Dermatophagoides pteronyssinus (Dp) were submitted to subcutaneous AIT (SCIT) (depigmented-polymerized Dp allergen extracts) for 3 years. Nasal allergen challenge (NACs) with Dp extract were performed before and 3 years after AIT. NAC response was assessed with peak nasal inspiratory flow (PNIF) and symptom score of Lebel. NACs were considered positive when there was a flow decrease of ≥ 20% in PNIF and a score of symptoms ≥ 3 points. Demographic data and NAC results were analysed. Results. We included 32 paediatric patients (mean age 9.9±3.08 years, 18 female) and 10 adult patients, (mean age 30.4±12.2 years, 7 female). The symptom score obtained at the 1st minute, 5th minute, 15th minute and 30th minute in response to NAC, were reduced after AIT. The nasal inspiratory flow decrease induced by NAC was also reduced after AIT.  This reduction in nasal reactivity was observed in paediatric and in adult patients, both with statistical significance. Conclusions. AIT induced a decrease in Dp-nasal specific reactivity in children with LAR. This decline of nasal response to allergen exposure, after AIT treatment, emphasis the interest of this therapeutic approach in LAR, even in paediatric patients.

A retrospective analysis of the clinical efficacy in patients treated with Alternaria alternata and Dermatophagoides farinae immunotherapy.

Background: The clinical efficacy of allergen-specific immunotherapy (AIT) for Alternaria alternata (A. alt) and Dermatophagoides farinae (Der f) extracts remains largely unknown in China. We sought to retrospectively evaluate the efficacy caused by AIT agents manufactured in China of patients who are sensitized to A. alt and Der f. Methods: Patients aged 5-27 years with asthma and perennial allergic rhinitis (AR), and AIT with A. alt and Der f were recruited, and then classified into two groups: A. alt-AIT (n = 31) and A. alt + Der f-AIT group (n = 39). All data were gathered retrospectively, including biological parameters, pulmonary function, and symptom and medication scores. Results: 70 patients who underwent A. alt and Der f AIT were enrolled. A significant improvement was observed in the values of FEV1% (P < 0.0001) and MEF 25 (P = 0.023) of lung function. Both the rhinitis symptoms and combined symptoms and medication scores for asthma decreased after AIT (by 45.3% and 80.3%, respectively, P < 0.0001 for each). Nearly 67% improvement rate (P < 0.0001) occurred in rhinoconjunctivitis quality of life, and a great increase existed in Asthma Control Test (ACT) score (P < 0.0001) after at least 1 year AIT, although there were no significant changes between these two groups. Besides, no significance was displayed in specific IgE to different allergens. Conclusion: AIT with A. alt and Der f extracts had clinical efficacy for many patients in China, with a reduction of symptom and medication scores, and great improvement in spirometry function.

Current perspective on allergen immunotherapy for food allergies.

Food allergies are an increasing global problem and societal issue. In addition to the potential for severe allergic reactions from accidental ingestion, food allergies impose a significant burden on the quality of life, nutrition, cost of living, and social activities of both those afflicted and their caregivers. Strict avoidance of allergens and use of emergency medications to treat allergic reactions are the traditional management and treatment strategies; however, significant progress has been made in recent years toward better treatment of food allergies. Many clinical trials on food allergen immunotherapy (oral, epicutaneous, and sublingual) have revealed its efficacy in increasing reaction thresholds and desensitization. These positive results led to the first FDA approval of peanut oral immunotherapy (OIT). However, safer and more effective approaches are required, and adjunct treatments and allergen modifications are being considered. More than 100 facilities in Japan conduct OIT, and numerous studies on it have been reported. Unlike in Europe and the US, stepwise oral food challenges with dietary guidance are conducted separately from the OIT. This review describes the current perspectives on allergen immunotherapy for the treatment of food allergies, focusing on evidence from Japan.

Sequential model for predicting patient adherence in subcutaneous immunotherapy for allergic rhinitis.

Objective: Subcutaneous Immunotherapy (SCIT) is the long-lasting causal treatment of allergic rhinitis (AR). How to enhance the adherence of patients to maximize the benefit of allergen immunotherapy (AIT) plays a crucial role in the management of AIT. This study aims to leverage novel machine learning models to precisely predict the risk of non-adherence of AR patients and related local symptom scores in 3 years SCIT. Methods: The research develops and analyzes two models, sequential latent-variable model (SLVM) of Stochastic Latent Actor-Critic (SLAC) and Long Short-Term Memory (LSTM). SLVM is a probabilistic model that captures the dynamics of patient adherence, while LSTM is a type of recurrent neural network designed to handle time-series data by maintaining long-term dependencies. These models were evaluated based on scoring and adherence prediction capabilities. Results: Excluding the biased samples at the first time step, the predictive adherence accuracy of the SLAC models is from 60% to 72%, and for LSTM models, it is 66%-84%, varying according to the time steps. The range of Root Mean Square Error (RMSE) for SLAC models is between 0.93 and 2.22, while for LSTM models it is between 1.09 and 1.77. Notably, these RMSEs are significantly lower than the random prediction error of 4.55. Conclusion: We creatively apply sequential models in the long-term management of SCIT with promising accuracy in the prediction of SCIT nonadherence in AR patients. While LSTM outperforms SLAC in adherence prediction, SLAC excels in score prediction for patients undergoing SCIT for AR. The state-action-based SLAC adds flexibility, presenting a novel and effective approach for managing long-term AIT.

The evidence for commercial house dust mite immunotherapy products: A pragmatic systematic review with narrative synthesis.

House dust mite (HDM) allergen immunotherapy (AIT) has an established role in the treatment of perennial allergic rhinitis (AR) and allergic asthma (AA) triggered by HDM sensitization. We aimed to identify all double-blind, randomized, placebo-controlled trials of HDM AIT for the treatment of AR and AA in humans and to summarize the evidence for AIT products that are currently manufactured and available for clinical use. A total of 56 eligible double-blind, randomized, placebo-controlled trials of HDM AIT for the treatment of AA and/or AR in humans fit the inclusion criteria and investigated a total of 14 commercial AIT products; together, the 56 studies enrolled a total of 14,619 patients. Of the 56 studies, 39 studies investigated the current manufacturer-recommended maintenance dose (MRMD) of the product, and 17 investigated other doses. We identified 39 studies (12,539 patients randomized) for 8 sublingual immunotherapy (SLIT) products and 17 studies (2,080 patients randomized) for subcutaneous immunotherapy products. For AR, 3 products, the ALK 12 standardized-quality (SQ-HDM) SLIT tablet, the ALK 6 SQ-HDM tablet, and the SG 300 index of reactivity SLIT tablet, had both dose-finding studies (DFSs) and phase III definitive studies (DSs) to demonstrate efficacy of the MRMD of the product. For AA, 2 products, the ALK 12 SQ-HDM SLIT tablet and the ALK 6 SQ-HDM tablet, had both DFSs and DSs for the MRMD. No subcutaneous immunotherapy product had a paired DFS and DS supporting the MRMD. A total of 30 studies of products no longer commercially manufactured were excluded. This study will help to inform clinical care and product selection for the treatment of HDM-induced AR and AA.

Individualized sublingual immunotherapy with dynamic maintenance dose ascending for house dust mite-induced allergic rhinitis.

BACKGROUND: Precision dosing in sublingual immunotherapy (SLIT) has become a hotspot gradually, yet no standardized dose adjustment pattern for house dust mite (HDM)-SLIT. This study aims to investigate the clinical feasibility of the dynamic maintenance dose ascending regimen for individualized SLIT. METHODS: A total of 258 allergic rhinitis (AR) patients treated with HDM-SLIT were included in this retrospective study. Patients were divided into the regular dose (RD) group (n = 101) and the high dose (HD) group (n = 157) according to different maintenance dosages of SLIT. In the RD group, patients received the fixed dose recommended by the manufacturer. In the HD group, patients received a maximum tolerance dose determined by dynamic dose ascending. The clinical efficacy was evaluated by combined symptom and medication score (CSMS) and visual analogue scale score (VAS) at the baseline, 0.5-year, 1-year, and 2-year. The safety was evaluated by adverse events (AEs). RESULTS: Significant reductions of CSMS and VAS at 0.5-year, 1-year, and 2-year were observed in both the RD group and the HD group compared to the baseline (P < 0.05). In addition, greater improvements in these clinical parameters from 0.5- to 2-year were found in the HD group compared to the RD group (P < 0.05). For subgroup analysis in the HD group, no significant differences in CSMS and VAS were observed among subgroups of patients <14 years old and patients ≥14 years old (P > 0.05). No serious AEs in the two groups and no significant differences were observed between the AE incidence rate of the RD group and HD group during the incremental and maintenance phases. CONCLUSIONS: The 2-year HDM-SLIT with dynamic maintenance dose ascending regimen offers an "optimal" treatment for AR patients while maintaining safety. This study introduced a pattern for individualized dose adjustment in clinical practice, offering potential benefits for AR patients.

Management of Allergic Rhinitis in the United Arab Emirates: Expert Consensus Recommendations on Allergen Immunotherapy.

Allergic rhinitis (AR) is a chronic inflammatory condition of the upper airways caused by a type I hypersensitivity reaction triggered by environmental allergens. AR is associated with significant morbidity and affects patients' quality of life, emotional well-being, productivity, and cognitive functioning. As AR prevalence and morbidity have increased significantly worldwide, similar observations have been noted in the United Arab Emirates (UAE) with AR becoming a potential public health issue. Management of AR in the UAE is mainly provided by non-allergy specialists relying on first-line treatments such as intranasal steroids and antihistamines, with often suboptimal and short-term efficacy. Allergen Immunotherapy (AIT) is the only currently available disease-modifying treatment option in the form of either subcutaneous or sublingual allergen immunotherapy that has been proven to have long-term benefits. This article aims to provide recommendations regarding the use of AIT for managing AR in the UAE, considering both the current landscape in the Emirati healthcare system and local experience.

Allergen immunotherapy adverse events in adults with respiratory allergies-data from ADER: An EAACI task force report.

BACKGROUND: Registries can yield important insights on allergen immunotherapy (AIT) outcomes in daily clinical practice. However, systematic recordings of adverse events (AE) due to AIT in real-life are lacking. METHODS: The Allergen Immunotherapy Adverse Events Registry (ADER) is a prospective, multicenter registry on real-life AIT safety. Data on adults (>18 years old) with respiratory allergies receiving AIT with mites, pollens, epithelia, and/or molds were retrieved and analyzed from ADER. The frequency, characteristics and risk factors of AE were investigated. The MedDRA terminology was used to record AE. RESULTS: A total of 1545 individuals with a mean age of 33 ± 10 years receiving 1815 AIT courses (n = 1060 sublingual (SLIT); n = 755 subcutaneous (SCIT)) in centers from eight countries were included. Patients had allergic rhinitis (65%) or, asthma only (3.7%) or rhinitis with asthma (31.2%). Grass was the most frequent specific sensitizer (60.7%), followed by mites (45.5%), birch pollen (20.6%), epithelia (16.1%), and molds (8%). There were 296 AE recorded in 115 patients (7.4%). A higher frequency of AE occurred during up-dosing (59%) compared to maintenance. Severe reactions were rare (0.2%), all in the context of SCIT. After 6 weeks of maintenance only one moderate AE was recorded. The most frequently reported symptoms were from the respiratory system and the skin. Having asthma, doing SCIT, AIT with mugwort, cat, or birch were associated with higher risk for AE while the use of allergoids induced lower risk. CONCLUSION: In real life clinical practice, AIT-associated AE occur in a minority of patients, while severe reactions are rare. The presence of asthma and use of SCIT are risk factors, while the use of modified allergens lowers the risk.

Whence and wherefore IgE?

Despite the near ubiquitous presence of Ig-based antibodies in vertebrates, IgE is unique to mammals. How and why it emerged remains mysterious. IgE expression is greatly constrained compared to other IgH isotypes. While other IgH isotypes are relatively abundant, soluble IgE has a truncated half-life, and IgE plasma cells are mostly short-lived. Despite its rarity, IgE is consequential and can trigger life-threatening anaphylaxis. IgE production reflects a dynamic steady state with IgG memory B cells feeding short-lived IgE production. Emerging evidence suggests that IgE may also potentially be produced in longer-lived plasma cells as well, perhaps as an aberrancy stemming from its evolutionary roots from an antibody isotype that likely functioned more like IgG. As a late derivative of an ancient systemic antibody system, the benefits of IgE in mammals likely stems from the antibody system's adaptive recognition and response capability. However, the tendency for massive, systemic, and long-lived production, common to IgH isotypes like IgG, were likely not a good fit for IgE. The evolutionary derivation of IgE from an antibody system that for millions of years was good at antigen de-sensitization to now functioning as a highly specialized antigen-sensitization function required heavy restrictions on antibody production-insufficiency of which may contribute to allergic disease.

Allergen immunotherapy in asthma.

Allergen immunotherapy (AIT), including SCIT and SLIT, is a treatment that involves the administration of allergens to which patients with allergic diseases have been sensitized. HDM-SCIT for asthma is indicated in cases of HDM-sensitized allergic asthma with normal lung function. HDM-SCIT improves asthma symptoms and AHR, and decreases the medication dose. Importantly, AIT can improve other allergic diseases complicated by asthma, such as allergic rhinitis, which can also contribute to the improvement of asthma symptoms. Several studies have suggested that HDM-SLIT also attenuates the risk of asthma exacerbations, and improves lung function in asthma cases with allergic rhinitis. Furthermore, AIT can modify the natural course of allergic diseases, including asthma. For example, the effects of AIT are maintained for at least several years after treatment discontinuation. AIT can prevent the onset of asthma when introduced in allergic rhinitis, and can also inhibit or reduce new allergen sensitizations. Recent data have suggested that AIT may suppress non-targeted allergen-induced immune responses in addition to targeted allergen-induced responses, and suppress infections of the lower respiratory tract by enhancing IFN responses.

A human monoclonal antibody based immunoenzymetric assay to measure Fel d 1 concentrations in cat hair and pelt allergenic extracts.

In the United States, 19 allergen extracts of different specificities are standardized, which means that their potencies are determined in comparison to a US reference standard. For cat allergen extracts, potency is determined by measuring Fel d 1 content expressed in in Fel d 1 units, and with a unitage that correlates with skin test reactions (bioequivalent allergy units or BAU). Currently, Fel d 1 content is measured with a radial immunodiffusion (RID) assay that uses polyclonal sheep antisera to detect the allergenic protein by producing a white precipitin line in agar gel. However, the RID is considered cumbersome, and the polyclonal sera may qualitatively vary among animals and may recognize epitopes irrelevant to human allergic disease. In this report, we describe a quantitative two-site immunoenzymetric assay (IEMA) for Fel d 1 that uses immobilized capture and soluble biotin-labeled detection Fel d 1-specific human IgE monoclonal antibodies (mAb) that have been class-switched to IgG4. Together, they sandwich Fel d 1 molecules from extracts. Using purified natural Fel d 1 as a calibrator, the historically reported ∼4 micrograms Fel d 1/Fel d 1 unit assignment was directly measured in this mAb-based IEMA at 3.12 ± 0.24 micrograms of Fel d 1 per Fel d 1 unit. This IEMA appears to be equivalent to RID in the measurement of biological potencies of commercial cat hair and cat pelt extracts marketed in the United States.

Transition between subcutaneous and sublingual allergen immunotherapy: Recommendations of the Brazilian Association of Allergy and Immunology (ASBAI).

The use of allergen immunotherapy (AIT) in Brazil has specific regional conditions owing to the pattern of allergen sensitization, as well as to genetic, socioeconomic, and cultural characteristics. This review article aims to discuss the clinical practice of AIT by the subcutaneous or sublingual route in Brazil, addressing the possibilities of transition between these forms of administration. A systematic review using the PubMed and Cochrane databases was performed, and the websites of major allergy and immunology organizations were consulted. Knowledge of the mechanism of action of subcutaneous immunotherapy and sublingual immunotherapy, together with Brazilian real-life experience, allowed us to establish recommendations regarding switching routes of AIT administration in selected cases. Careful analysis of each clinical situation is necessary to perform the transition between subcutaneous and sublingual allergen immunotherapy.

House dust mite immunotherapy: A real-world, prescription data-based analysis.

BACKGROUND: House dust mite (HDM) sensitisation can contribute to the development of allergic rhinoconjunctivitis (AR) or allergic asthma (AA). As treatment, allergen immunotherapy (AIT) is a promising approach, since it aims building immunotolerance against allergens, therewith establishing long-term efficacy. The evaluation of AIT has been investigated in many randomised controlled trials, whereas few real-world evidence studies are available. METHODS: We used data from the longitudinal prescription data base IQVIA™ LRx. Data on initial AIT prescriptions against HDM from January 2009 to December 2013 was analysed regarding treatment (subcutaneous AIT with either depigmented polymerised allergen extract [dSCIT] or other allergens [oSCIT], or sublingual immunotherapy [SLIT]) and treatment duration. Treatment groups were compared with a control group of AR patients not receiving AIT. Data on symptomatic medication was collected until February 2017 and progression of AR and AA was compared. RESULTS: Data of 7260 patients with AIT prescriptions and of 21,780 control patients was analysed. AIT was associated with a significant decrease of AR medication intake compared with control (dSCIT: -34.0%, p < 0.0001; oSCIT: -25.7%, p < 0.0001; SLIT: -37.7%, p = 0.0026). In asthmatics, SCIT was associated with a significant decrease of asthma medication compared with control (dSCIT: -45.2%, p < 0.0001; oSCIT: -32.9%, p < 0.0001). Further, a significantly reduced likelihood for onset of asthma medication was demonstrated in patients treated with SCIT compared with controls (dSCIT OR: 0.759, p = 0.0476; oSCIT OR: 0.815, p = 0.0339). CONCLUSION: Real-world data analyses indicate that AIT, particularly given via a subcutaneous route, reduces the need of medication against AR and AA and might delay the onset of asthma medication in patients with AR.

Vitamin D and allergic diseases.

In recent years, the relationship between vitamin D and allergic diseases has received widespread attention. As a fat-soluble vitamin, vitamin D plays a crucial role in regulating the immune system and may influence the onset and progression of diseases such as atopic dermatitis, allergic rhinitis, and asthma. To understand the underlying mechanisms, we have summarized the current research on the association between vitamin D and allergic diseases. We also discuss the impact of vitamin D on the immune system and its role in the course of allergic diseases, particularly focusing on how vitamin D supplementation affects the treatment outcomes of these conditions. We aim to provide a theoretical basis and practical guidance for optimizing the management and treatment of allergic diseases by modulating vitamin D levels.

Patient compliance to sublingual immunotherapy for mite-induced allergic rhinitis: A retrospective study.

Background: Compliance to sublingual immunotherapy (SLIT) is generally low, resulting in reduced short- and long-term clinical efficacy. Compliance is a critical factor determining the success of allergic rhinitis (AR) treatment. Objective: To analyze the compliance of patients with house dust mite (HDM)-induced AR to SLIT and the impact of coronavirus disease 2019 (COVID-19) on compliance. Methods: The clinical data of 3117 patients with HDM-induced AR who started SLIT between July 2018 and April 2022 were retrospectively reviewed. We assessed the reasons for non-compliance and the changes in non-compliance during the COVID-19 pandemic compared to the pre-pandemic period. Results: Of 3117 patients, 507 (16.27%) patients (ages, 5-67 years) were identified as non-compliant. The most common reason for non-compliance was poor efficacy (27.22%). The non-compliance rate was highest during 24-36 months of SLIT (28.13%, 153/544), followed by 12-24 months (7.02%, 91/1296). Non-compliance was significantly higher in adolescents/adults than in children (P = 0.000). Although the generalized linear model analysis indicated that compliance was affected by the COVID-19 pandemic during 3-6 months of SLIT, the overall compliance to SLIT was not significantly affected by the pandemic, according to the Kaplan-Meier survival analysis. Conclusions: The non-compliance rate of SLIT in this study was low, and poor efficacy was the most common reason for non-compliance. The compliance of adolescents/adults was lower than that of children. The COVID-19 pandemic did not significantly impact compliance to SLIT, which is an appropriate strategy for the home treatment of AR patients during major public health events.

Efficacy and safety of sublingual immunotherapy using house dust mite tablet for 1-4 years old children with perennial allergic rhinitis.

BACKGROUND: Sublingual immunotherapy (SLIT) for perennial allergic rhinitis (AR) has not been extensively studied in preschoolers. We investigated the efficacy and safety of house dust mite (HDM) SLIT-tablet for children aged 1-4 years. METHODS: Children aged 1-4 years with AR were divided into SLIT (n = 22) and control (n = 12) groups based on their guardians' preferences. The SLIT group received a daily dose of 10,000 JAU of HDM SLIT-tablet for 12 months, whereas the control group received symptomatic treatment only. RESULTS: The baseline median age was 41 and 34 months in the SLIT and control groups, respectively, and the median AR symptom score was 4 for both groups. Compared with baseline, the AR symptom score had decreased significantly in the SLIT group after 12 months (score: 3, p = .002), whereas it tended to increase in the control group (score: 6, p = .08). Adverse reactions to SLIT were mild and occurred in eight patients (36%). In the SLIT group, Dermatophagoides (D.) farinae-specific IgE (sIgE) levels increased during the first 6 months and decreased to baseline levels at 12 months. In the control group, D. farinae-sIgE levels had increased significantly at 12 months compared to baseline (p = .01). D. farinae-specific IgG4 and HDM IgE-blocking factor levels were significantly increased at 12 months compared to baseline in the SLIT group only (p < .001). A lower wheezing frequency was seen in the SLIT group (0.3%) compared to the control group (0.7%). CONCLUSION: This pilot study demonstrated the efficacy, safety, and immunomodulatory effects of HDM SLIT-tablet in preschoolers with AR.