Bilateral nasal allergen provocation monitored with acoustic rhinometry. Assessment of both nasal passages and the side reacting with greater congestion: relation to the nasal cycle

Numerical simulation of the influence of nasal cycle on nasal airflow

To study the characteristics of nasal airflow in the presence of nasal cycle by computational fluid dynamics. CT scan data of a healthy Chinese individual was used to construct a three-dimensional model of the nasal cavity to be used as simulation domain. A sinusoidal airflow velocity is set at the nasal cavity entrance to reproduce the breathing pattern of a healthy human. There was a significant difference in the cross-sectional area between the two sides of the nasal cavity. Particularly, the decongested side is characterized by a larger cross-section area, and consequently, by a larger volume with respect to the congested side. The airflow velocity, pressure, and nasal resistance were higher on the congested narrow side. The temperature regulation ability on the congested narrow side was stronger than that on the decongested wider side. During the nasal cycle, there are differences in the nasal cavity function between the congested and decongested sides. Therefore, when evaluating the impact of various factors on nasal cavity function, the nasal cycle should be considered.

First-in-human phase 2 trial with mite allergoids coupled to mannan in subcutaneous and sublingual immunotherapy

BACKGROUND

Polymerized allergens conjugated to non-oxidized mannan (PM-allergoids) are novel vaccines targeting dendritic cells (DCs). Previous experimental data indicate that PM-allergoids are readily taken up by DCs and induce Treg cells. This first-in-human study was aimed to evaluate safety and to find the optimal dose of house dust mite PM-allergoid (PM-HDM) administered subcutaneously (SC) or sublingually (SL).

METHODS

In a randomized, double-blind, double-dummy, placebo-controlled trial, 196 subjects received placebo or PM-HDM at 500, 1000, 3000, or 5000 mannan-conjugated therapeutic units (mTU)/mL in 9-arm groups for 4 months. All subjects received 5 SC doses (0.5 ml each) every 30 days plus 0.2 ml SL daily. The primary efficacy outcome was the improvement of titrated nasal provocation tests (NPT) with D. pteronyssinus at baseline and at the end of the study. All adverse events and reactions were recorded and assessed. Secondary outcomes were the combination of symptom and medication scores (CSMS) and serological markers.

RESULTS

No moderate or severe adverse reactions were reported. Subjects improving the NPT after treatment ranged from 45% to 62% in active SC, 44% to 61% in active SL and 16% in placebo groups. Statistical differences between placebo and active groups were all significant above 500 mTU, being the highest with 3000 mTU SL (p = 0.004) and 5000 mTU SC (p = 0.011). CSMS improvement over placebo reached 70% (p < 0.001) in active 3000 mTU SC and 40% (p = 0.015) in 5000 mTU SL groups.

CONCLUSIONS

PM-HDM immunotherapy was safe and successful in achieving primary and secondary clinical outcomes in SC and SL at either 3000 or 5000 mTU/ml.

Precision Medicine in Mite Allergic Rhinitis

It is well-known that a correct diagnosis is necessary for effective treatment. In the case of allergic rhinitis due to mites, imprecise diagnosis with effective but improvable methods means that in many cases an optimal result is not reached in patients. The diagnosis of allergic rhinitis due to mite sensitization have to require more homogeneously reproducible diagnostic tests that try to encompass many more of the protein antigens contained in them. With the few proteins that the problem has usually focused on, there is no they would cover many of the clinically relevant allergens in a large proportion of patients. In this mini-review we try to highlight the importance of having good allergenic sources and briefly gather information on various allergenic proteins included in mites that could be clinically relevant. All this to try to get closer to a more accurate diagnosis. We are also talking about two diagnostic tools that are clearly out of use and that should be promoted in the consultations to obtain an even greater and better outcome in patients.

Nasal challenges in allergen immunotherapy trials

PURPOSE OF REVIEW

The nasal allergen challenge (NAC) model can be a valuable diagnostic tool for allergic rhinitis. Alongside its clinical use, NACs can be used as primary and secondary endpoints in studies evaluating allergen immunotherapy (AIT) products for allergic rhinitis treatment. This review will discuss the technical aspects of the NAC model and provide a summary of recent studies using NACs to assess existing and new AIT treatments.

RECENT FINDINGS

Over the last 2 years, both titrated and single-dose nasal challenge protocols have been used to evaluate immunotherapies targeting grass, birch, house dust mite, and cat allergens. Early efficacy and dose-finding trials showed improvements in allergic symptoms and nasal tolerance to allergens after AIT treatment with standardized extracts or modified forms of whole allergen. NACs were also used in two proof-of-concept studies to illustrate the efficacy of intralymphatic immunotherapy with two concomitant allergens and subcutaneous immunotherapy with Fel d 1-specific IgG-blocking antibodies.

SUMMARY

Along with existing therapies, nasal challenges are useful in evaluating AIT treatments in the very early stages of clinical development. However, because of the variety in challenge techniques and symptom assessments available, special attention must be placed in the protocol design in order to compare the study results with existing NAC publications.

EAACI Position paper on the standardization of nasal allergen challenges

Nasal allergen challenge (NAC) is an important tool to diagnose allergic rhinitis. In daily clinical routine, experimentally, or when measuring therapeutic success clinically, nasal allergen challenge is fundamental. It is further one of the key diagnostic tools when initiating specific allergen immunotherapy. So far, national recommendations offered guidance on its execution; however, international divergence left many questions unanswered. These differences in the literature caused EAACI to initiate a task force to answer unmet needs and find a consensus in executing nasal allergen challenge. On the basis of a systematic review containing nasal allergen challenges of the past years, task force members reviewed evidence, discussed open issues, and studied variations of several subjective and objective assessment parameters to propose a standardized way of a nasal allergen challenge procedure in clinical practice. Besides an update on indications, contraindications, and preparations for the test procedure, main recommendations are a bilaterally challenge with standardized allergens, with a spray device offering 0.1 mL per nostril. A systematic catalogue for positivity criteria is given for the variety of established subjective and objective assessment methods as well as a schedule for the challenge procedure. The task force recommends a unified protocol for NAC for daily clinical practice, aiming at eliminating the previous difficulty of comparing NAC results due to unmet needs.

Nonspecific Hyper-reactivity and Localized Allergy

Objective

Disagreement between results of skin prick test (SPT) and nasal provocation tests (NPT) causes difficulty in differential diagnosis of allergic rhinitis (AR) and nonallergic rhinitis (NAR). We hypothesized this discrepancy could be due to the nonspecific hyper-reactivity (NHR) and localized allergy of the nasal cavity.

Study Design

Prospective pilot.

Setting

Academic tertiary rhinologic practice.

Subjects and Methods

Sixty patients with AR and 62 with NAR were enrolled. We categorized patients according to results of SPT and NPT. We compared: (1) the clinical characteristics and severity of the disease, (2) change of minimal cross-sectional area (MCA) and total nasal volume (TNV) after normal saline (NS) challenge, and (3) change of nasal symptoms and acoustic parameters after intranasal house dust mite (HDM) challenge between groups.

Results

Patients in groups A (SPT[+]/NPT[+]) and C (SPT[–]/NPT[+]) complained of more persistent discomfort than those in groups B (SPT[+]/NPT[–]) and D (SPT[–]/NPT[–]). The proportion of moderate to severe symptoms was significantly higher in groups A, B, and C compared to group D. After NS challenge, MCA/TNV showed a significantly greater decrease in groups A (MCA: 27.6% ± 21.3%, TNV: 24.6% ± 16.4%) and C (MCA: 31.2% ± 24.0%, TNV: 24.1% ± 23.4%) compared to groups B (MCA: 0.1% ± 13.2%, TNV: 3.9% ± 13.5%) and D (MCA: 2.1% ± 12.1%, TNV: 2.0% ± 17.2%) ( P < .05). After HDM challenge, groups A/B showed a greater decrease in MCA (Group A: 62.4% ± 16.1%, Group B: 6.4% ± 11.3%) compared to groups C/D (Group C: 45.5% ± 14.4%, Group D: –3.0% ± 9.5%).

Conclusion

NHR and/or localized allergy should be considered in patients with rhinitis whose SPT and NPT results are not in agreement.

Evaluation of acoustic rhinometry in a nasal provocation test with allergic rhinitis

Objective

The nasal provocation test is not widely available due to lack of standardized methods and related research. We evaluated the clinical utility of the nasal provocation test using acoustic rhinometry.

Study Design

All patients underwent skin tests and were graded according to severity of reaction.

Methods

We performed nasal provocation tests using acoustic rhinometry in patients with allergic rhinitis from January 2003 to December 2006. A total of 836 patients participated in our study. The mean age was 36 years and the male:female ratio was 5:4.

Results

The mean nasal volume was 10.86 cm3 and the mean minimal cross-sectional area (MCA) was 0.66 cm3 before the study. Relationship between the severity of the reaction and change in mean nasal volume and MCA was statistically significant. The relationship between the severity of the reaction against the antigen and the severity of clinical symptoms was also statistically significant.

Conclusion

The nasal provocation test can be helpful in evaluating the severity of allergic rhinitis. However, we must be careful in interpreting the results alone.

Acoustic rhinometry in the practice of allergy

OBJECTIVE

To provide a comprehensive practical overview of the use of acoustic rhinometry in the practice of allergy.

DATA SOURCES

An all-inclusive PubMed search was conducted for articles on acoustic rhinometry that were published in peer-reviewed journals, between 1989 and 2006, using the keywords acoustic rhinometry, allergic rhinitis, and nasal provocation testing.

STUDY SELECTION

The expert opinion of the authors was used to select studies for inclusion in this review.

RESULTS

Acoustic rhinometry is a sound-based technique used to measure nasal cavity area and volume. It has been validated by comparison to measurements with computed tomography and magnetic resonance imaging. Acoustic rhinometry requires minimal patient cooperation and may be used in adults, children, and infants. It is used by medical practitioners to diagnose and evaluate therapeutic responses in conditions such as rhinitis and to measure nasal dimensions during allergen provocation testing. Acoustic rhinometry also provides a visual reflection of the nasal response to therapy, which may be useful in increasing compliance to prescribed medications.

CONCLUSIONS

Acoustic rhinometry is a safe, noninvasive, objective, and validated measure of nasal obstruction that appears to be of practical use in the diagnosis and management of inflammatory diseases of the upper airways.

Acoustic rhinometry in nasal provocation test in perennial allergic rhinitis

Acoustic rhinometry is one method to evaluate nasal geometry by an acoustic reflection technique. The aim of this study was to investigate the changes in acoustic rhinometry after nasal provocation in patients with exclusively perennial allergic rhinitis. In 19 patients, acoustic rhinometry and active anterior rhinomanometry were performed before and after nasal provocation test. There was a statistically significant nasal flow reduction measured by active anterior rhinomanometry after nasal provocation (p < 0.05) and a median symptom score of four points, both indicating a positive response to nasal provocation. On the other hand, there was no statistically significant change in the values of acoustic rhinometry after nasal provocation (p > 0.05). In patients with exclusively perennial allergic rhinitis, acoustic rhinometry does not seem to significantly change after nasal provocation. In contrast, active anterior rhinomanometry values decreased significantly after nasal provocation. The presented results indicate that acoustic rhinometry does not seem to be a diagnostic method superior to active anterior rhinomanometry in this context.

The effect of allergen provocation on the nasal cycle estimated by acoustic rhinometry

CONCLUSION

The overall duration and reciprocity of the nasal cycle were not changed after allergen provocation. The duration of immediate response was 38 min, but the amplitude of the nasal cycle was increased significantly after allergen provocation.

OBJECTIVE

Nasal airflow is asymmetrical and subjected to spontaneous reciprocal changes which are referred to as the nasal cycle. Limited information is available on how this is affected by allergens. The purpose of this study was to evaluate the effects of allergen provocation on the nasal cycle.

MATERIALS AND METHODS

This study was performed on 25 patients with allergic rhinitis and 25 subjects in a control group with no symptoms of allergic rhinitis. Acoustic rhinometry was used to test patients before and after allergen provocation. The patients underwent acoustic rhinometry at 15-min intervals for evaluation of nasal cycle and 3-min intervals for immediate response.

RESULTS

With the allergic patients, 21 of the 25 patients (84.0%) showed a nasal cycle and they still had a nasal cycle after the allergen provocation. In the study on the changes in the immediate responses, the average recovery time was 38 min and the reduction rate of the non-patent side was higher than that of the patent side. Also, the average period of the nasal cycle was 153 min before the allergen provocation and 140 min on average after the allergen provocation; there were no statistical differences. The amplitude of each nasal cycle increased after allergen provocation and the difference had statistical meaning.

Acoustic rhinometry: should we be using it?

PURPOSE OF THE REVIEW

The purpose of this review is to examine the role of acoustic rhinometry in clinical practice. Although acoustic rhinometry was first described for clinical use in 1989, it is not in common use today. Should we be using it? Yes. I think we should be using it more often. This review provides an update of the new standard for interpretation and expanded clinical uses.

RECENT FINDINGS

The most significant advances in the past year in this area have been the publication of standards for its clinical use. In addition, the repertoire of clinical problems that can be analyzed objectively with acoustic rhinometry has expanded to include turbinoplasty, sleep disorders, more types of cosmetic/reconstructive procedures, sinus surgery, vasomotor rhinitis, maxillofacial expansion procedures, and aspirin and methacholine challenge. (Its ability for pediatric disorders, such as adenoidectomy, has been reaffirmed.) Some case examples are included to demonstrate the utility of acoustic rhinometry for 'mixed' pathology.

SUMMARY

Acoustic rhinometry is a rapid, objective, painless, noninvasive technique for assessing nasal airway obstruction. Recently, standards have been developed that aid its expansion for clinical use. Expanded clinical applications include sleep disorders, cosmetic/reconstructive and maxillofacial disorders, sinus and turbinate procedures, and pediatrics. Acoustic rhinometry should be utilized to improve our ability to practice evidence-based medicine in rhinology.