Intralymphatic immunotherapy with birch and grass pollen extracts. A randomized double-blind placebo-controlled clinical trial

Full consideration of the pollen exposure effect in clinical trial design for pollen-induced allergic rhinitis

INTRODUCTION

Allergic rhinitis (AR) is global health concern with an increasing prevalence. Among them, pollen-induced AR (PIAR) exhibits more severe and intense symptoms, decreased quality of life, prominent local inflammation, and is thus more challenging to control. Due to the difficulties in disease control, in recent years, an increasing number of treatment methods, including pharmacotherapy, allergen-specific immunotherapy, and newly developed biologics, have focused on PIAR. It has been shown that the pollen exposure has a significant impact on the symptoms of PIAR and the efficacy of intervention. From this perspective, clinical trials for PIAR need to take full account of pollen exposure, especially when assessing efficacy.

AREAS COVERED

This review summarized the effect of pollen exposure on PIAR, including immune responses, symptoms and clinic visits. Current definitions for the pollen season (PS) and the peak pollen season (PPS) are discussed. Based on the previous PIAR-related clinical studies and the available recommendations for clinical trial design, a detailed account of trial protocols which fully considered pollen exposure is provided.

EXPERT OPINION

Pollen exposure has a significant impact on PIAR. With fully considering the pollen exposure in the clinical trial design for PIAR, future protocols for PIAR-related studies may be more objective and better harmonized and, therefore, comparable.

Role of allergen immunotherapy and biologics in allergic diseases

The rise in the prevalence of allergic diseases has become a global health burden. Allergic diseases are a group of immune-mediated disorders characterized by IgE-mediated conditions resulting from a type 2 helper T cell (Th2)-skewed immune response. This review aims to comprehensively summarize recent research on the roles of allergen immunotherapy (AIT) and biologics in allergic diseases. Specifically, we review the mechanisms of AIT and biologics in modulating innate and adaptive immunity involved in allergic disease pathogenesis, as well as their safety and efficacy in the treatment of allergic diseases. We also discuss current new AIT strategies such as recombinant allergen-based vaccines and allergen extract nanoencapsulation. Further research is needed to understand immune tolerance mechanisms beyond the Th2 pathway and to characterize immunological changes in responders and nonresponders to AIT or biologics. This additional research may uncover new targets for monitoring treatment responses and developing personalized treatment strategies for allergic diseases.

Mechanism and clinical evidence of immunotherapy in allergic rhinitis

Allergic rhinitis is a common upper airway disease caused by hypersensitivity to various aeroallergens. It causes increased inflammation throughout the body and may be complicated by other otolaryngological pathologies such as chronic hyperplastic eosinophilic sinusitis, nasal polyposis, and serous otitis media. Allergic rhinitis is an IgE-mediated disease and immunotherapy can be a possible approach for patients to limit the use of antihistamines and corticosteroids. There is evidence that allergen immunotherapy can prevent the development of new sensitizations and reduce the risk of later development of asthma in patients with allergic rhinitis. However, some patients do not benefit from this approach and the efficacy of immunotherapy in reducing the severity and relapse of symptoms is still a matter of debate. This review highlights new aspects of allergic rhinitis with a particular focus on the impact of sexual dimorphism on the disease manifestation and efficacy to the allergen specific immunotherapy.