The efficacy and safety of sublingual immunotherapy in children and adult patients with allergic rhinitis

Increased Nasal Blimp1 + Treg Cells After Sublingual Immunotherapy Reflect the Efficacy of Treatment in Allergic Rhinitis

INTRODUCTION

Allergen-specific immunotherapy (AIT) plays a pivotal role in altering the immune status and tissue responses in allergic rhinitis (AR). This study focuses on the impact of sublingual immunotherapy (SLIT) involving dust mite drops, exploring the modulation of regulatory T cells (Treg) and their specific marker, BLIMP1, in the nasal mucosa.

METHODS

Immune cells were isolated from nasal lavage fluid of patients with AR undergoing SLIT (n = 94). Treg cells were analyzed for BLIMP1 expression, and chemokine levels associated with Treg recruitment were assessed using Luminex assay. Patients were categorized on the basis of SLIT efficacy and followed for changes after discontinuation.

RESULTS

SLIT induced a significant increase in nasal Treg cells (7.09 ± 2.59% vs. 0.75 ± 0.27%, P < 0.0001). BLIMP1 expression in Treg cells notably increased after SLIT (0.36 ± 0.22% to 16.86 ± 5.74%, P < 0.0001). Ineffective SLIT cases exhibited lower levels of nasal Treg and Blimp1 + Treg cells (both P < 0.0001). Receiver operating characteristic (ROC) analysis confirmed their potential as efficacy predictors (AUC = 0.908 and 0.968, respectively). SLIT discontinuation led to a significant reduction in Treg and Blimp1 + Treg cells (P < 0.001), emphasizing their maintenance during treatment. Pro-inflammatory cytokines decreased (P < 0.001), while CCL2 associated with Treg recruitment increased (P = 0.0015).

CONCLUSION

Elevated nasal Blimp1 + Treg cells serve as a predictive biomarker for SLIT responsiveness in pediatric AR. Their influence on immunotherapy effectiveness contributes to a nuanced understanding of SLIT mechanisms, allowing for disease stratification and personalized treatment plans. This study offers scientific support for predicting SLIT efficacy, enhancing the prospects of improved treatment outcomes in AR.

Allergen immunotherapy in China

Allergen immunotherapy (AIT) is an etiological treatment strategy that involves administering escalating doses of clinically relevant allergens to desensitize the immune system. It has shown encouraging results in reducing allergy symptoms and enhancing patients' quality of life. In this review, we offer a thorough overview of AIT in China, examining its efficacy, safety, current practices, and prospects. We further underscore the progress made in AIT research and clinical applications, as well as the distinct challenges and opportunities that China faces in this area.

Chinese Guideline on Allergen Immunotherapy for Allergic Rhinitis: The 2022 Update

In the last few decades, there has been a progressive increase in the prevalence of allergic rhinitis (AR) in China, where it now affects approximately 250 million people. AR prevention and treatment include allergen avoidance, pharmacotherapy, allergen immunotherapy (AIT), and patient education, among which AIT is the only curative intervention. AIT targets the disease etiology and may potentially modify the immune system as well as induce allergen-specific immune tolerance in patients with AR. In 2017, a team of experts from the Chinese Society of Allergy (CSA) and the Chinese Allergic Rhinitis Collaborative Research Group (C2AR2G) produced the first English version of Chinese AIT guidelines for AR. Since then, there has been considerable progress in basic research of and clinical practice for AIT, especially regarding the role of follicular regulatory T (TFR) cells in the pathogenesis of AR and the use of allergen-specific immunoglobulin E (sIgE) in nasal secretions for the diagnosis of AR. Additionally, potential biomarkers, including TFR cells, sIgG4, and sIgE, have been used to monitor the incidence and progression of AR. Moreover, there has been a novel understanding of AIT during the coronavirus disease 2019 pandemic. Hence, there was an urgent need to update the AIT guideline for AR by a team of experts from CSA and C2AR2G. This document aims to serve as professional reference material on AIT for AR treatment in China, thus improving the development of AIT across the world.

Dropouts From Sublingual Immunotherapy and the Transition to Subcutaneous Immunotherapy in House Dust Mite-Sensitized Allergic Rhinitis Patients

Purpose: Both subcutaneous immunotherapy (SCIT) and sublingual immunotherapy (SLIT) are effective in reducing symptoms and medication scores and inducing long-term efficacy in patients with allergic rhinitis (AR). However, SLIT has been associated with poor patient adherence. This study investigates the factors impacting dropout rates from SLIT in house dust mite (HDM)-sensitized AR patients.

Methods: A retrospective study was performed to analyze dropout rates and reasons in AR patients receiving Dermatophagoides farinae (Der f) SLIT with a follow-up period of 2 years.

Results: A total of 719 HDM-sensitized AR patients received Der f-SLIT. Dropout rates increased with time and most occurred after 1 year of SLIT. By month 24, 654 (91%) patients had discontinued SLIT. The dropout rates by month 24 were 100, 90.1, and 91.1% in children <5 years old, children aged 5–18 years old, and adults ≥ 18 years old, respectively. Combination with allergic asthma and mono- or multi-sensitization to other aeroallergens did not affect the dropout rates. The most common self-reported reasons for dropouts were refusal of continuation, dissatisfaction with the efficacy, transition to SCIT, and adverse effects. Refusal of continuation increased with age, whereas transition to SCIT decreased with age. Ninety-seven cases transitioned from SLIT to SCIT, and the transition rates increased with time. Comorbid allergic asthma did not affect the transition rates. However, multi-sensitization was associated with a slightly higher rate of transition to SCIT. The most common reason for the transition was dissatisfaction with the efficacy (54.6%), which was only reported by patients older than 5 years. For children who began SLIT at younger than 5 years old, the most common reason (81.2%) for transition was age reaching 5 years.

Conclusions: HDM-SLIT has a very high dropout rate, which is mainly due to refusal of continuation and dissatisfaction with the efficacy. Transitioning from SLIT to SCIT may help keep these patients on AIT and thus increase adherence and long-term efficacy.

A Retrospective Cohort Study of Sublingual Immunotherapy with Standardized Dermatophagoides farinae Drops for Allergic Rhinitis

INTRODUCTION

To evaluate the efficacy and safety of sublingual immunotherapy (SLIT) with standardized Dermatophagoides farinae (Df) drops in monosensitized and polysensitized patients with allergic rhinitis (AR) and to analyze the adverse events (AEs).

METHODS

A retrospective analysis was performed using data for 68 patients with AR who received SLIT. The patients were divided into a monosensitized group (36 cases) and a polysensitized group (32 cases) based on serum-specific IgE test results. In the two groups of patients, total nasal symptoms score (TNSS), total medication score (TMS), visual analog scale (VAS) score, and AEs before treatment and at 1, 3, 6, and 12 months of treatment were evaluated.

RESULTS

Compared with that before treatment, the TNSS, TMS, and VAS score in the monosensitized and polysensitized groups all decreased significantly at 3, 6, and 12 months of SLIT (all P < 0.05). There were no significant differences in treatment efficacy indicators between the two groups at all treatment time points (all P > 0.05). In terms of safety, compared with 1 month after initiating SLIT, the incidence of AEs in the monosensitized and polysensitized groups at 6 and 12 months of treatment significantly decreased (all P < 0.05). There was a statistically significant decrease in the incidence of AEs in both groups at 6 months compared with 3 months of treatment (χ² = 1.92 and 5.85, respectively, all P < 0.05). The difference in incidence of AEs between the monosensitized and polysensitized groups was not statistically significant at any treatment time point (all P > 0.05). AEs in all patients were local mild reactions; no serious AEs were found.

CONCLUSION

SLIT with standardized Df drops has similar efficacy and safety for monosensitized and polysensitized patients with AR. AEs mostly occurred during the first 3 months of SLIT in both the monosensitized and polysensitized groups, and the incidence of AEs gradually decreased as the course of treatment extended.

Efficacy and adherence of sublingual immunotherapy in patients aged 60 to 75 years old with house dust mite-induced allergic rhinitis

PURPOSE

This study aimed to evaluate the efficacy and adherence of sublingual immunotherapy (SLIT) for house dust mite (HDM)-induced allergic rhinitis (AR) patients over 60 years old.

MATERIALS AND METHODS

Eighty-six AR patients aged 60-75 years old were randomly divided in the control and treatment group as 1:1 ratio. The control group was treated with standard pharmacotherapy while the treatment group was treated with SLIT plus pharmacotherapy on demand. Patients adherence, combined symptom and medication score (CSMS), visual analog scale (VAS), and presence of adverse events were evaluated in the baseline and after 6-months, 12-months and 24-months treatment.

RESULTS

Twenty-five (58.1%) subjects in the treatment group and 20 (46.5%) subjects in the control group completed the study (P > 0.05). The major reasons for premature cessation were out of touch and relieved symptoms. At the same time, CSMS and VAS of the patients over 60 years old in both groups significantly decreased from baseline to any post-baseline time point (all P < 0.05). The comparison of CSMS and VAS between the two groups revealed statistically significant differences in favor of the SLIT group at month 24 (P < 0.05), whereas no differences at month 6 and month 12 (all P > 0.05).

CONCLUSION

41.9% of the patients dropped out within 2 years of SLIT treatment and the major reasons for premature cessation were out of touch and relieved symptoms. This study suggested that SLIT plus pharmacotherapy provided a greater clinical benefit than pharmacotherapy alone at two years.

Enhanced Efficacy of Dust Mite Sublingual Immunotherapy in Low-Response Allergic Rhinitis Patients after Dose Increment at 6 Months: A Prospective Study

BACKGROUND

Several studies have suggested that sublingual immunotherapy (SLIT) involves a dose-response relationship and inadequate dosage might not achieve a favorable clinical effect.

OBJECTIVE

The aim of this prospective study was to investigate the efficacy and safety of increasing SLIT dosage at 6 months in patients with house dust mite-induced allergic rhinitis (AR) who had low response to treatment.

METHODS

A total of 157 AR participants aged 4-60 years were enrolled and received SLIT with Dermatophagoides farinae drops. After 6 months of SLIT, patients were interviewed and then classified into a high-response (HR) group and a low-response (LR) group based on the combined symptom and medication score (CSMS) reduction rate. Patients with a CSMS reduction rate over 50% were defined as HR and continued the original dose, while patients with a CSMS reduction rate ranging from 20 to 50% were defined as LR and received an increased dose (percentage of dosage increment, 33.33% for patients aged <14 years and 50% for patients aged ≥14 years). Patients with a CSMS reduction rate below 20% were considered nonresponse (NR) and recommended to withdraw from SLIT. CSMS, visual analog scale (VAS), and adverse events were assessed at 0.5, 1, 2, and 3 years during the 3-year treatment.

RESULTS

A total of 54 and 56 patients completed the treatment in the HR and LR groups, respectively. The CSMS and VAS of both groups decreased significantly at 6 months (p < 0.05). Significant differences between the two groups were found in CSMS and VAS at 6 months and 1 year (p < 0.05), but not in later follow-ups (p > 0.05). The improvement of adults in the LR group was significantly lower than that of children at 6 months (p < 0.05), but there was no difference in later follow-ups (p > 0.05). There was no difference in CSMS or VAS in patients with monosensitization and polysensitization in the same treatment group at 1 year and in subsequent visits (p> 0.05). Overall, 47 patients withdrew from this study due to NR (n = 22) and other reasons (n = 25).

CONCLUSIONS

Six months might be a critical time point for efficacy assessment and dosage adjustment for AR patients after SLIT. In patients with low response, dosage enhancement within a certain range may enhance the effectiveness of SLIT.

Risk Factors for Safety of Allergen-Specific Sublingual Immunotherapy in Children with Allergic Rhinitis

A good compliance often attributes to good efficacy and safety of sublingual immunotherapy (SLIT). However, few studies have been conducted on the safety of SLIT treatment in children. We aimed to confirm the pretreatment parameters to predict the safety in children who underwent SLIT. 601 children with allergic rhinitis (AR) treated with SLIT were enrolled in this study. Baseline clinical information and laboratory parameters were collected. The clinical response and adverse events (AEs) were recorded and evaluated. A multivariate logistic regression model was established to confirm the predictors for AEs. The AEs were reported in 75 children (13.8%). The serum-specific IgE (s-IgE) level was significantly correlated with the occurrence of AEs by multivariate logistic regression analysis. Our receiver operating characteristic (ROC) analysis of the serum s-IgE levels &#x3e;21.6 IU/mL had the best sensitivity (83.7%) and specificity (76.7%) to predict safety. The serum s-IgE level was significantly correlated with safety of SLIT in children, which may be helpful for patient selection before SLIT.

Principles of Allergen Immunotherapy and Its Clinical Application in China: Contrasts and Comparisons with the USA

Allergen immunotherapy (AIT) for allergic rhinitis (AR), asthma, and other allergic diseases has developed quickly. House dust mite (HDM), Artemisia (wormwood), Humulus japonicus (Japanese hop), Alternaria alternata, and Cladosporium herbarum are the five most common inhalant allergens in China. AIT has been performed in China for over 60 years. With the support of the Chinese Medical Association (CMA) and the Chinese Medical Doctors Association (CMDA), the Chinese College of Allergy and Asthma (CCAA) was established in 2016 as a specialized branch of CDMA and is the main certification authority for AIT. Chinese allergists and scientists have made tremendous progress in the development of AIT. There have been many publications by Chinese allergists and scientists worldwide encompassing original research studies, systematic reviews, case studies, and clinical trials. Currently, conventional subcutaneous immunotherapy (SCIT) is the preferred AIT in China, but sublingual immunotherapy (SLIT) is beginning to gain recognition. An increasing number of clinical trials have been conducted to investigate the clinical efficacy and side effects of SLIT and SCIT. In China, HDM is the only commercial standardized allergen extracts in clinical use, whereas the others are crude allergen extracts. Besides standardized allergen extracts, other forms of hypoallergenic extracts are still being investigated and developed in China. Immunotherapy in China is similar to that in the USA in which allergen extracts can be mixed for SCIT. However, allergen extracts cannot be mixed for SCIT in Europe.

Sublingual immunotherapy of house dust mite respiratory allergy in China

Sublingual immunotherapy (SLIT) has been widely used for the treatment of allergic respiratory diseases, but many problems remain unsolved. Currently available data suggest that SLIT is very effective in children and adults with IgE-mediated respiratory diseases. Most allergists in China generally believe that SLIT is suitable for allergic rhinitis and asthma due to its safety and tolerability. SLIT for three years is suitable for patients to acquire stable therapeutic effects, and the efficacy of single-allergen SLIT for polysensitized patients has also been confirmed. Nevertheless, there are still several factors restricting its application in China, such as the uncertainty of its long-term effects and the prevention of new sensitizations onset, the risk of asthma attacks, the low public awareness of SLIT and poor compliance by patients. This is a narrative review of current evidence on SLIT coming from China.

The efficacy of sublingual immunotherapy for allergic diseases in Asia

Sublingual immunotherapy (SLIT) has been proven to be safe and effective from an abundance of Western literature, but data from Asia is less complete. This review aims to examine the basic science, safety and efficacy of SLIT in Asian patients, and to determine future research needs in Asia. We performed a literature search on PUBMED, Scopus, and Cochrane Library database for articles on SLIT originating from Asian countries through Nov 2017. There were 18 randomized, double-blind, placebo-controlled trials, of which 9 involved solely paediatric subjects. Overall, sublingual immunotherapy is safe and is efficacious in Asian populations in allergic rhinitis (AR) and asthma. House dust-mite SLIT is effective in both mono- and polysensitized AR patients. Efficacy of SLIT is comparable to subcutaneous immunotherapy. Data on long term efficacy is lacking. A disproportionate majority of research originates from China and Japan, reflecting an asymmetry of access to SLIT within Asia. Significant disparities exist in the development of the allergy speciality, prescription patterns of SLIT, and pharmacological potencies of different SLIT products within and between Asian nations. We conclude that current available evidence suggests SLIT is efficacious in Asians but data quality of evidence is hampered by non-placebo controlled studies with methodological limitations. More data is needed in South and Southeast Asian populations. Future efforts may be directed towards improving access to SLIT in developing countries, standardization of SLIT dosage, and evaluating long term clinical outcomes.