Mechanisms in AIT: Insights 2021

Purified Free Mannan Promotes Tolerogenic Responses in Peanut-Stimulated Human Dendritic Cells

INTRODUCTION

IgE-mediated peanut allergy is an important public health problem of increasing prevalence leading to anaphylactic reactions both in children and adults. Allergen-specific oral immunotherapy (OIT) is the single treatment with the potential capacity to modify the course of the disease, but it still faces some drawbacks in terms of efficacy, safety, patients' adherence, and cost. Alternative strategies, including the use of novel adjuvants, to overcome such limitations are highly demanded. The main aim of this study was to search for potential novel adjuvants for peanut OIT by assessing the capacity of free purified mannan and different toll-like receptor ligands (TLR-Ls) to immunomodulate the responses of human monocyte-derived dendritic cells (hmoDCs) to peanut allergens.

METHODS

Monocytes were isolated from PBMCs of healthy donors and differentiated into hmoDCs. Flow cytometry, ELISA, coculture, and suppression assay were performed to assess the effects of TLR-Ls, mannan, and crude peanut extract (CPE) in hmoDCs.

RESULTS

Purified free mannan increased the expression levels of HLA-DR, CD86, CD83, and PD-L1 and induced a higher IL-10/IL-6 cytokine ratio in hmoDCs compared to the stimulation with different TLR-Ls. Mannan significantly increased the expression of HLA-DR, the maturation marker CD83, the tolerogenic marker PD-L1, as well as the production of IL-10, IL-6, and TNF-α in CPE-stimulated hmoDCs. Supporting these tolerogenic properties, mannan also significantly increased the frequency of FOXP3+ regulatory T cells generated by CPE-treated hmoDCs with functional suppressive capacity.

CONCLUSIONS

We uncover that purified free mannan induces tolerogenic responses in human DCs stimulated with peanut allergens, suggesting mannan as a suitable potential novel adjuvant to be exploited in the context of OIT for peanut allergy.

The Role of Regulatory T Cells in Allergic Diseases: Collegium Internationale Allergologicum (CIA) Update 2024

BACKGROUND

Allergy represents a major health problem of increasing prevalence worldwide with a high socioeconomic impact. Our knowledge on the molecular mechanisms underlying allergic diseases and their treatments has significantly improved over the last years. The generation of allergen-specific regulatory T cells (Tregs) is crucial in the induction of healthy immune responses to allergens, preventing the development and worsening of allergic diseases.

SUMMARY

In the last decades, intensive research has focused on the study of the molecular mechanisms involved in Treg development and Treg-mediated suppression. These mechanisms are essential for the induction of sustained tolerance by allergen-specific immunotherapy (AIT) after treatment discontinuation. Compelling experimental evidence demonstrated altered suppressive capacity of Tregs in patients suffering from allergic rhinitis, allergic asthma, food allergy, or atopic dermatitis, as well as the restoration of their numbers and functionality after successful AIT.

KEY MESSAGE

The better understanding of the molecular mechanisms involved in Treg generation during allergen tolerance induction might well contribute to the development of novel strategies for the prevention and treatment of allergic diseases.

The long-term efficacy of intra-cervical lymphatic immunotherapy on adults with allergic rhinitis: A randomized controlled study

BACKGROUND

The efficacy and safety of the novel immunotherapy method, intra-cervical lymphatic immunotherapy (ICLIT), need to be investigated. Comparing it with subcutaneous immunotherapy (SCIT), we clarified the long-term efficacy and safety of intra-cervical lymphatic immunotherapy on allergic rhinitis (AR), and investigated the improvement of clinical efficacy of the booster injection at 1 year after ICLIT treatment.

METHODS

Ninety adult patients with dust mite allergy were randomly divided into 3 groups: 30 in the SCIT group, 30 in the ILCLIT group, and 30 in ICLIT booster group. Changes in total symptom score (TSS), nasal symptom score (TNSS), ocular symptom score (TOSS) and total medication score (TMS) were evaluated in the three groups. Adverse reactions were recorded, and serum dust mite specific IgE (sIgE) and specific IgG4 were assessed in the ICLIT group and ICLIT booster group.

RESULTS

TSS, TNSS, TOSS, and TMS scores were significantly lower in the three groups at 36 months after treatment (p < 0. 05). And at 36 months the ICLIT-booster group showed results similar to SCIT and superior to ICLIT (p < 0. 05). Serum specific IgE decreased in all three groups at 12 and 36 months after treatment, p < 0.01. The ICLIT group and the ICLIT booster group showed a significant increase in sIgG4, p < 0.01. None of the patients in the three groups had any serious systemic adverse effects during the 3-year follow-up.

CONCLUSION

The ICLIT treatment is effective and safe on AR. One booster injection of allergens at 1 year can greatly improve its long-term efficacy.

TRIAL REGISTRY

Clinical trial registration number: ChiCTR1800017130.

Advancements in Allergen Immunotherapy for the Treatment of Atopic Dermatitis

Atopic dermatitis (AD) is a chronic inflammatory skin condition that affects individuals of all age groups, manifesting as a spectrum of symptoms varying from mild to severe. Allergen immunotherapy (AIT) involves the administration of allergen extracts and has emerged as a potential treatment strategy for modifying immune responses. Its pathogenesis involves epidermal barrier dysfunction, microbiome imbalance, immune dysregulation, and environmental factors. Existing treatment strategies encompass topical steroids to systemic agents, while AIT is under investigation as a potential immune-modifying alternative. Several studies have shown reductions in the severity scoring of atopic dermatitis (SCORAD) scores, daily rescue medication use, and visual analog scale (VAS) scores following AIT. Biomarker changes include increased IgG4 levels and decreased eosinophil counts. This review provides valuable insights for future research and clinical practice, exploring AIT as a viable option for the management of AD.

Long-term benefit after allergen immunotherapy to HDM in elderly patients with allergic rhinitis

Introduction

Allergen immunotherapy (AIT) is an effective therapy for allergic rhinitis and may have long-term benefits. However, these benefits have not been strictly defined for older people.

Aim

The evaluation of the effectiveness of AIT in patients over 60 with allergic rhinitis and house dust mites (HDM) allergy over a period of 7 years was performed.

Material and methods

Patients after three years of HDM-AIT were observed to assess the sustained clinical effect of treatment. The average adjusted symptom score (AAdSS) and sIgG4 were monitored for 7 years after sublingual (SLIT) and injection AIT (SCIT).

Results

After 3 years of HDM-AIT, a significant clinical effect was observed in the group after SLIT and SCIT based on AAdSS compared to the baseline and the placebo group (p < 0.05). After 7 years of follow-up, there was a sustained trend of decrease in clinical symptoms in desensitized patients relative to placebo. Serum sIgG4 was constantly present in all desensitized patients.

Conclusions

AIT may be beneficial for treating seniors with allergic rhinitis and allergies to house dust mites.

Post-COVID mRNA-vaccine IgG4 shift: worrisome?

COVID-19 vaccines play a key role in ending the pandemic. Unraveling the immunological phenomena involved in offering protective immunity is the cornerstone of achieving such success. This perspective evaluates the possible mechanisms and implications of IgG4 production in response to mRNA-based COVID-19 vaccines.