Clinical efficacy and tolerability of a steady dosage schedule of local nasal immunotherapy. Results of preseasonal treatment in grass pollen rhinitis

LNIT-Local nasal immunotherapy in allergic rhinitis: revisited evidence and perspectives

PURPOSE OF REVIEW

Allergen immunotherapy (AIT) is a personalized treatment approach for the allergic airway disease. The most common routes of administration are subcutaneous and sublingual. Local nasal immunotherapy (LNIT) presents another alternative route for allergen desensitization. Nasal mucosa is the first entry site of pathogens and numerous lymphoid organs are located in this area, making LNIT a favorable method for triggering immune tolerance. LNIT has shown promising results in reducing symptoms and medication use in allergic rhinitis patients. Over time, difficulties in dosing adjustments have made this method less popular. Recent advances in intranasal drug delivery systems warrant re-examination of LNIT as a viable option for the treatment of the allergic airway disease.

RECENT FINDINGS

The scope of the review includes evidences of LNIT in human trials including comparison with placebo and conventional method of immunotherapy. Recent articles regarding the mechanism of LNIT and the challenges of intranasal drug delivery are reviewed. Advances in the LNIT delivery system which have overcome previous limitations demonstrate promising effects.

SUMMARY

LNIT presents a judicious alternative for noninjection AIT. The evidences from previous clinical trials and the novel improvement of drug delivery system will lead into the future allergen vaccine production.

Local nasal immunotherapy for allergic rhinitis: A systematic review and meta-analysis

INTRODUCTION

Local nasal immunotherapy (LNIT), an alternative noninjection immunotherapy method, is theoretically an efficient method for inducing immunotolerance directly in the affected organ. LNIT is more convenient and less invasive than injection immunotherapy, with fewer systemic reactions. The development of adjuvants to overcome LNIT's limitations raises the possibility of it being an alternative allergen immunotherapy.

OBJECTIVES

To evaluate the clinical and immunological efficacy and safety of LNIT for patients with allergic rhinitis.

METHODS

A systematic search for randomized controlled trials comparing LNIT and placebo was performed using OVID Medline and Embase. Outcomes were total nasal symptom score (TNSS), symptom-medication score (SMS), medication score, immunological assessment, and nasal provocation threshold. Data were pooled for meta-analysis.

RESULTS

A total of 20 studies with 698 participants were included. The LNIT group had greater posttreatment improvement in TNSS, SMS, and medication score than control (TNSS: standardized mean difference [SMD], -1.37 [95% confidence interval [CI], -2.04 to -0.69]; SMS: SMD, -1.55 [95% CI, -2.83 to -0.28]; and medication score: SMD, -1.09 [95% CI, -1.35 to -0.83]). Immunological assessments showed no significant differences in serum-specific IgE (mean difference [MD], 6.35; 95% CI, -4.62 to 17.31), nasal IgE (MD, -0.59; 95% CI, -1.99 to 0.81), or nasal eosinophil cationic protein (MD, 7.63; 95% CI, -18.65 to 33.91). Only serum IgG significantly increased with LNIT (MD, 0.45; 95% CI, 0.20, 0.70). Posttreatment, nasal provocation threshold was higher with LNIT (MD, 27.30; 95% CI, 10.13-44.46). No significant adverse events were reported.

CONCLUSIONS

LNIT is a safe alternative allergen immunotherapy route without significant adverse events. It improves clinical symptoms, reduces medication usage, and increases the nasal provocation threshold.

The effect of local nasal immunotherapy in allergic rhinitis: using strips of the allergen dermatophagoides pteronyssinus

Local nasal immunotherapy (LNIT) has been reported to be effective for mite-induced allergic rhinitis. However, its compliance is poor due to persistent nasal reactions and difficult application. The main objective of this study was to develop a Dermatophagoides pteronyssinus (Der p)-coated strip for self-application and to evaluate its clinical efficacy. Randomized, double-blind, placebo-controlled trials were carried out to evaluate the efficacy and compliance of LNIT. A total of 35 patients with allergic rhinitis from the allergy clinic were recruited to receive four months of LNIT. Clinical efficacy was evaluated by the symptoms of sneezing, rhinorrhea and nasal stuffiness. Local and systemic effects were evaluated by measuring histamine and eosinophil cationic protein (ECP) in nasal discharge and allergen-specific IgG1, IgG4 and IgE in sera. LNIT with Der p-coated strips could reduce nasal symptoms and modulate the serum levels of Der p-specific IgG1, IgG4 and IgE. The secretion of both histamine and ECP was reduced within four months after treatment. When the symptomatic and immunological changes were compared between active treatment and placebo groups, the improvements were greater in the active treatment groups for all three symptom scores. There were no severe adverse events except nasal response persisting within the first month in some cases. LNIT with a steady dose of Der p-coated strips can be self-administered at home without any systemic reactions. Both local and systemic immune responses were observed after LNIT. This therapeutic modality may serve as a good alternative treatment for allergic rhinitis.

Local nasal specific immunotherapy for allergic rhinitis

The possibility of producing local hyposensitization by administering allergens via mucosal routes was envisaged at the beginning of 1900, and local nasal immunotherapy has been extensively studied since the 1970s. Presently, there are 21 randomized controlled trials being conducted with the most common allergens, consistently showing the clinical efficacy of local nasal immunotherapy for rhinitis. Other advantages are that it has an optimal safety profile and can be self-administered at home by the patient. Moreover, there are several data from animal models and from humans that confirm the immunomodulatory effect of intranasally administered antigens. On the other hand, local nasal immunotherapy seems to be effective only on rhinitis symptoms and requires a particular technique of administration. For these reasons, its clinical use is progressively declining in favour of the sublingual route although nasal immunotherapy is validated in official documents and remains a viable alternative to injection.

Production of salivary immunoglobulin A and suppression of Dermatophagoides pteronyssinus-induced airway inflammation by local nasal immunotherapy

BACKGROUND

Local nasal immunotherapy (LNIT) is an effective immunotherapeutic modality, especially when targeting a single immunodominant peptide from an allergen. However, the working mechanisms of LNIT are poorly understood. We hypothesized that LNIT with a mixture of group 2 allergens of Dermatophagoides pteronyssinus (Der p 2) protein and fungal immunomodulatory peptide (FIP) would generate suppression of Der p-induced airway inflammation through immunoglobulin (Ig) A secretion in the airways.

METHOD

Mice were sensitized with recombinant Der p 2 (rDer p 2) and Der p followed by LNIT with rDer p 2 in conjunction with FIP. After intratracheal challenge with rDer p 2 and Der p, the airway inflammation was determined by analyzing the cell subpopulation and cytokine concentration in the bronchoalveolar lavage fluid. The allergen-specific IgE, IgG2a and IgG in the sera and IgA in the saliva were measured by ELISA.

RESULTS

LNIT with rDer p 2 in conjunction with FIP could downregulate the lymphocyte infiltration in both rDer p 2- and Der p-induced airway inflammation. Both total and specific IgA in the saliva were increased after LNIT. Serum levels of IL-4, IL-10 and specific IgE were reduced and the specific IgG2a and IgG increased after LNIT. After LNIT, there was a reduction of airway hypersensitivity at 30 min after allergen challenge in the rDer p 2-and Der p-sensitized mice, with a significant decrease only in rDer p 2-sensitized mice.

CONCLUSION

LNIT with rDer p 2 in conjunction with FIP was not only able to suppress rDer p 2-induced airway inflammation but also generate suppression of Der p-induced airway inflammation. The simultaneous reduction of IL-4 and IL-10 indicated that IL-10-producing cells were not activated by LNIT. The increment of IgA in the airway might play a role in the prevention of airway inflammation.

Sublingual immunotherapy: an update

PURPOSE OF REVIEW

Sublingual immunotherapy is now officially accepted as a viable alternative to the traditional subcutaneous route, and it is widely used especially in European countries. Despite the large amount of experimental evidence on the safety and efficacy of the method, some concerns still exist, and several aspects need to be clarified: magnitude of the efficacy, adherence, long-lasting effect and others. Recently published studies have provided answers to some of these points.

RECENT FINDINGS

The most recent studies have shown that sublingual immunotherapy exerts a long-lasting effect up to 5 years after discontinuation and that it is able to prevent the onset of new sensitizations. Moreover, when systematically assessed, the adherence to treatment is quite satisfactory, despite the treatment being self-administered. In addition, evidence has been provided that sublingual immunotherapy is effective in treating allergic conjunctivitis, and a metaanalysis has confirmed its efficacy in rhinitis. Moreover, some studies have addressed the possibility of simplifying the schedule of administration by shortening the build-up phase.

SUMMARY

More and more new data on sublingual immunotherapy are rapidly appearing in the international literature. These data confirm the clinical value of this treatment and show that it is comparable to subcutaneous immunotherapy from several points of view.

Efficacy of local nasal immunotherapy for Dp2-induced airway inflammation in mice: Using Dp2 peptide and fungal immunomodulatory peptide

BACKGROUND

Local nasal immunotherapy (LNIT) is an effective immunotherapy. Peptides derived from the group 2 allergen of Dermatophagoides pteronyssinus, Dp2 28-40 and Dp2 28-40A, and fungal immunomodulatory peptide (FIP) have been shown to act as T(H)1 potential and response-inducing adjuvant. LNIT by the use of Dp2 peptides in conjunction with FIP were investigated.

OBJECTIVE

We sought to determine whether Dp2-induced airway inflammation in mice could be downregulated by Dp2 peptides or a mixture of Dp2 peptides with FIP.

METHOD

Mice were sensitized with rDp2 followed by LNIT with Dp2 peptides, FIP, or FIP and a mixture of Dp2 peptides. After intratracheal challenge with rDp2, the airway inflammation and hyperresponsiveness were determined by bronchoalveolar lavage fluid (BALF) analysis and methacholine challenge.

RESULTS

Both Dp2 peptides and FIP were able to inhibit rDp2-induced airway inflammation and airway hyperresponsiveness. An increase in IFN-gamma and a decrease in IL-5 in BALF and sera were found after LNIT with Dp2 peptides, FIP, and mixtures of both. Serum levels of TGF-beta were reduced after LNIT with FIP and Dp2 28-40. Penh values were significantly decreased after methacholine challenge in both the early and late phase.

CONCLUSIONS

LNIT with allergen-derived peptides and FIP can produce an anti-inflammatory effect on allergen-induced airway inflammation. LNIT with selected peptides and FIP might be a good alternative therapy for allergic airway disease.

Noninjection routes for immunotherapy

Allergen specific immunotherapy, together with drugs and allergen avoidance, is a cornerstone in the management of respiratory allergy. The traditional subcutaneous route is burdened with the risk of severe adverse events; therefore, safer routes of administration (noninjection or local routes) have been investigated and developed. Controlled trials failed to demonstrate the clinical efficacy and the safety of oral and bronchial administration, and these routes have been abandoned. Local nasal immunotherapy proved effective and safe in 17 of 18 controlled trials; thus it is considered a viable route of immunotherapy. Nevertheless, nasal immunotherapy is effective in rhinitis only and requires a particular administration technique; therefore its use is slowly declining. The sublingual route is supported by numerous controlled trials showing its efficacy in asthma and rhinitis in adults and children. The safety profile, assessed in clinical trials and postmarketing surveillance studies, is satisfactory; the most frequent side effects are gastrointestinal complaints, which can be easily managed by proper dose adjusting. Sublingual immunotherapy is now accepted by the World Health Organization as a valid alternative to the subcutaneous route also in children. Although the long-lasting efficacy has been recently documented for the sublingual route, several points still need to be elucidated, including mechanisms of action, optimal dosage, cost-effectiveness, and adherence.

Atopic diseases and upper respiratory infections

This article reviews information on the topics of asthma, allergic rhinitis, atopic dermatitis, food allergy, and upper respiratory infections. The asthma section includes a review of inhaled steroids and their potential side effects. New findings on the pathogenesis, triggers, and therapies of atopic dermatitis and new insights into food hypersensitivity reactions are presented. Recent publications in the areas of allergic rhinoconjunctivitis and upper respiratory infections are also reviewed.