Neural aspects of allergic rhinitis

Endoscopic vidian and vidian-branch neurectomy for refractory allergic rhinitis: A systematic review

BACKGROUND

Endoscopic vidian neurectomy is expected to provide good therapeutic relief in patients with allergic rhinitis (AR) being refractory to medication therapy or conservative surgery. However, the evidence bases for its benefit remain debatable. In this study, we conducted a systematic review and meta-analysis to clarify the therapeutic role of various forms of vidian neurectomy in refractory AR.

METHOD

Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines were used to conduct a systematic review of primary studies that reported original patient data for endoscopic vidian neurectomy (EVN) and vidian-branch neurectomy, which includes selective vidian neurectomy (SVN) and posterior nasal neurectomy (PNN). The primary outcome was patient-reported outcome measures (PROMs), including the Rhinoconjunctivitis Quality of Life Questionnaire (RQLQ) and Visual Analog Scale (VAS), to assess an improvement in nasal symptom severity and quality of patient's life. The incidence of surgical complications and other objective outcomes were considered secondary outcomes.

RESULTS

This review included 24 clinical studies involving 1677 patients with refractory AR, of which 510 patients in six studies had combined chronic rhinosinusitis with nasal polyps (CRSwNP) and 95 patients in one study had combined asthma. Postoperative PROMs were significantly better than preoperatively in almost all patients who underwent vidianp (RQLQ: standardized mean difference [SMD] = 2.66, 95% confidence interval [CI] = 2.40-2.92, p < 0.001; VAS: SMD = 5.15, 95% CI = 4.29-6.02, p < 0.001) or vidian-branch neurectomy (RQLQ in PNN: SMD = 3.29, 95% CI = 2.45-4.13, p < 0.001; VAS in PNN: SMD = 4.38, 95% CI = 3.41-5.34, p < 0.001), and were generally better than in the conservative treatment group. Dividing with 18 months as the cutoff point, a subgroup analysis of the follow-up period was conducted, and the results showed that both long-term and short-term postoperative patients had considerably reduced symptoms compared to the preoperative period. The two surgical procedures, SVN and PNN, attributed to vidian-branch neurectomy have extremely few complications. However, EVN is more likely to cause dry eyes and palatal numbness, with no other serious complications. In patients with AR and CRSwNP, vidian or selective vidian neurectomy combined with functional endoscopic sinus surgery (FESS) is more effective than conventional FESS (RQLQ: SMD = 2.17, 95% CI = 1.66-2.69, p < 0.001; VAS: SMD = 6.42, 95% CI = 4.78-8.06, p < 0.001). For patients who have both AR and asthma, SVN with pharyngeal branch excision is a potential treatment option.

CONCLUSION

EVN and vidian-branch neurectomy (including SVN and PNN) are effective treatments, but the former has a higher risk of complications. Additionally, vidian-branch neurectomy with FESS is beneficial for patients with mixed CRSwNP. SVN is a potential approach for patients with coexisting AR and asthma.

International consensus statement on allergy and rhinology: Allergic rhinitis - 2023

BACKGROUND

In the 5 years that have passed since the publication of the 2018 International Consensus Statement on Allergy and Rhinology: Allergic Rhinitis (ICAR-Allergic Rhinitis 2018), the literature has expanded substantially. The ICAR-Allergic Rhinitis 2023 update presents 144 individual topics on allergic rhinitis (AR), expanded by over 40 topics from the 2018 document. Originally presented topics from 2018 have also been reviewed and updated. The executive summary highlights key evidence-based findings and recommendation from the full document.

METHODS

ICAR-Allergic Rhinitis 2023 employed established evidence-based review with recommendation (EBRR) methodology to individually evaluate each topic. Stepwise iterative peer review and consensus was performed for each topic. The final document was then collated and includes the results of this work.

RESULTS

ICAR-Allergic Rhinitis 2023 includes 10 major content areas and 144 individual topics related to AR. For a substantial proportion of topics included, an aggregate grade of evidence is presented, which is determined by collating the levels of evidence for each available study identified in the literature. For topics in which a diagnostic or therapeutic intervention is considered, a recommendation summary is presented, which considers the aggregate grade of evidence, benefit, harm, and cost.

CONCLUSION

The ICAR-Allergic Rhinitis 2023 update provides a comprehensive evaluation of AR and the currently available evidence. It is this evidence that contributes to our current knowledge base and recommendations for patient evaluation and treatment.

Adhesion Promotes Allergic Rhinitis CD4+IL4+ T Cell Differentiation via ICAM1 and E-Selectin

BACKGROUND

Neuroimmune communication plays an important role in allergic inflammation, but the neuroimmune regulation of allergic rhinitis remains unclear.

OBJECTIVE

The goal of this study was to investigate the role of CD4-positive T lymphocyte (CD4+ T cells) adhesion to D-U87 neuron-like cells in mediating allergic rhinitis CD4+ T cell differentiation.

METHODS

D-U87 neuron-like cells were derived from the human glioblastoma U87 cell line. CD4+ T cells were isolated from human peripheral blood using a magnetic separation technique. In vitro coculture of D-U87 neuron-like cells and CD4+ T cells was established. The number of adherent CD4+ T cells was counted using a fluorescence microscope. The percentages of CD4+IFNγ+ and CD4+IL4+ T cells and the levels of IFNγ and IL4 cytokines in the supernatant were measured by flow cytometry.

RESULTS

The results showed that the number of adherent CD4+ T cells in patients with allergic rhinitis was significantly higher than that in healthy controls. In allergic rhinitis, the percentage of CD4+IL4+ T cells was significantly increased in the adherent group compared with that in the nonadherent group. Moreover, blocking ICAM1 and E-selectin decreased the number of adherent CD4+ T cells and the percentage of CD4+IL4+ T cells in allergic rhinitis.

CONCLUSION

Adhesion contributes to CD4+IL4+ T cell differentiation in the in vitro coculture system of D-U87 neuron-like cells and allergic rhinitis CD4+ T cells, which may provide new insights into therapeutic strategies for allergic rhinitis.

Diode laser-assisted inferior turbinoplasty in resistant cases of allergic rhinitis: a clinical and histopathological study

Chronic nasal obstruction owed to inferior nasal turbinate hypertrophy is one of the most common problems encountered in rhinology. When medical management fails, surgical reduction of hyperplastic inferior nasal turbinate is often used. Diode laser is appropriate for the use in the nasal turbinate. This study was designed to define the histopathologic changes in the inferior turbinate post diode laser turbinoplasty and evaluate the outcome in patients having allergic inferior turbinate hypertrophy that has not responded to the medical treatment. A prospective single-cohort study was carried out. Under general anesthesia, 18 patients underwent inferior turbinoplasty using diode laser 980 nm in the contact mode submucosally under guidance of a 4-mm nasal endoscope 0°. Inferior turbinate mucosa biopsy specimens were taken at the time of surgery, and after 3 months, they were histopathologically examined with assessment of the patients' symptoms. At 3 months postoperatively, histopathologic assessment demonstrated marked structural changes in diode laser-treated inferior turbinates including the predominance of fibrous tissue with diminution of seromucinous glands, venous sinusoids, and inflammatory cell infiltrate. Concurrently, 16 patients (89%) had no nasal obstruction, 15 patients (83%) had moderate-to-good improvement of rhinorrhea, whereas 13 patients (72%) had moderate-to-good improvement of sneezing. Diode laser produces histopathologic changes in the inferior turbinate soft tissues, providing excellent ablation of the soft tissue with controllable performance and good hemostasis. Therefore, it is a safe, minimally invasive, and effective procedure in relieving nasal obstruction secondary to inferior turbinate hypertrophy as well as other symptoms of allergic rhinitis.

Latent Myofascial Trigger Points Injection Reduced the Severity of Persistent, Moderate to Severe Allergic Rhinitis: A Randomized Controlled Trial

Background: Myofascial trigger points (MTrPs) injection has been effectively used for the management of chronic painful diseases. Latent MTrPs can induce autonomic nerve phenomena. In our clinic, we observed that allergic rhinitis (AR) symptoms significantly improved when latent MTrPs injection was performed for migraine. Objective: To compare the efficacy and safety between latent MTrPs injection and sublingual immunotherapy (SLIT) in patients with persistent, moderate to severe AR. Methods: This randomized controlled trial was conducted with 112 patients with AR. Patients were randomized to receive SLIT (n = 56) or latent MTrPs injection. Total nasal symptom score (TNSS, n = 56), nasal symptoms, medication days, and adverse events were evaluated during the 9 months follow-up period after treatment in both groups. Results: Latent MTrPs injection significantly reduced TNSS to a greater level from baseline (from 8.36 ± 1.96 to 4.43 ± 2.18) than SLIT (from 8.66 ± 2.31 to 7.80 ± 2.47) at week 1 (P < 0.001), and sustained the improvement in symptoms throughout to month 9. Latent MTrPs showed statistically significant differences vs. SLIT for the TNSS reduction both at month 2 (6.59 ± 2.37 vs. 2.64 ± 2.38; p < 0.001) and month 3 (4.59 ± 2.77 vs. 2.62 ± 2.43; p <0.001). Latent MTrPs also showed a better improvement in the onset time of efficacy compared with SLIT. Adverse reactions were few and non-serious in both treatment groups. Conclusions: Latent MTrPs injection significantly improved symptoms and decreased symptom-relieving medication use in patients with AR and was well tolerated. Clinical Trials Registration: Chinese Clinical Trial Registry, ChiCTR1900020590. Registered 9 January 2019, http://www.chictr.org.cn/index.aspx.

Cholinergic neuron-like D-U87 cells promote polarization of allergic rhinitis T-helper 2 cells

BACKGROUND

Parasympathetic nerve hypersensitivity contributes to the severity of allergic rhinitis (AR), but the precise mechanism underlying neuroimmune regulation in patients with AR remains unclear. This study investigated the effect of cholinergic nerve inhibition on AR CD4⁺ T-helper (Th)2-cell polarization and the underlying regulatory mechanism in vitro.

METHODS

An in-vitro neuroimmune coculture model of D-U87 cells and CD4⁺ T cells was established. D-U87 cells with cholinergic neuron characteristics were used as cholinergic neuron models. CD4⁺ T cells were derived from peripheral blood monocytes from AR patients (n = 60) and control subjects (n = 40). Th1- and Th2-cell percentages were measured by flow cytometry. Proteins involved in related signaling pathways were analyzed by protein chip assay and Western blotting.

RESULTS

The Th2-cell percentage among CD4⁺ T cells from AR patients was significantly increased after coculture with D-U87 cells and was decreased by ipratropium bromide (IB) treatment. In contrast, the Th1-cell percentage among control CD4⁺ T cells was significantly increased after coculture with D-U87 cells, but was unaltered by IB treatment. Furthermore, phosphorylated Akt (p-Akt) protein levels increased in CD4⁺ T cells from both controls and AR patients after coculture with D-U87 cells and decreased after IB treatment. However, higher p-Akt levels were observed in cells from AR patients than in cells from control subjects. Moreover, Akt inhibition decreased Th2-cell percentage in AR patients.

CONCLUSION

In-vitro cholinergic nerve inhibition with IB decreased AR CD4⁺ T-cell polarization into Th2 cells partially through an Akt-dependent mechanism.

Gastrin-Releasing Peptide Is Involved in the Establishment of Allergic Rhinitis in Mice

OBJECTIVE

Gastrin-releasing peptide (GRP) is a neuropeptide that targets transmembrane-type receptors. Its role in allergic rhinitis (AR) has yet to be investigated. The present study utilized the nasal mucosa of AR model mice to examine GRP and GRP receptor (GRPR) expression levels, localization, and other factors to evaluate their role in AR pathology.

STUDY DESIGN

In vivo study in an animal model.

METHODS

GRP and GRPR expression levels were examined in three different AR models established in BALB/c mice. In addition, a GRPR antagonist (RC-3095) was administered to AR mice to investigate its effect. The distribution of GRPR expression on mast cells in the nasal mucosa with AR was examined. Finally, we investigated the inhibitory effect of RC-3095 on allergy symptoms induced by histamine.

RESULTS

GRP and GRPR were highly expressed in the nasal mucosal epithelium and interstitial tissues surrounding the nasal glands in AR groups according to immunostaining. GRP and GRPR expression as determined by western blotting increased in the nasal mucosa as the degree of nasal sensitization increased. In addition, the average counts of sneezing and nasal rubbing after treatment in the AR + RC-3095 group were significantly lower than those in the AR + nasal saline group. Mast cells often colocalized with GRPR around nasal glands. Moreover, RC-3095 was effective in reducing sneezing induced by histamine.

CONCLUSION

The GRP-GRPR system is likely to be involved in allergic inflammation. This system may represent a novel therapeutic target for refractory AR.

LEVEL OF EVIDENCE

NA. Laryngoscope, E377-E384, 2018.

Effect of acupuncture on house dust mite specific IgE, substance P, and symptoms in persistent allergic rhinitis

BACKGROUND

Clinical evidence suggests that acupuncture improves symptoms in persistent allergic rhinitis, but the physiologic basis of these improvements is not well understood.

OBJECTIVE

A randomized, sham-controlled trial of acupuncture for persistent allergic rhinitis in adults investigated possible modulation of mucosal immune responses.

METHODS

A total of 151 individuals were randomized into real and sham acupuncture groups (who received twice-weekly treatments for 8 weeks) and a no acupuncture group. Various cytokines, neurotrophins, proinflammatory neuropeptides, and immunoglobulins were measured in saliva or plasma from baseline to 4-week follow-up.

RESULTS

Statistically significant reduction in allergen specific IgE for house dust mite was seen only in the real acupuncture group, from 18.87 kU/L (95% CI, 10.16-27.58 kU/L) to 17.82 kU/L (95% CI, 9.81-25.83 kU/L) (P = .04). A mean (SE) statistically significant down-regulation was also seen in proinflammatory neuropeptide substance P (SP) 18 to 24 hours after the first treatment from 408.74 (299.12) pg/mL to 90.77 (22.54) pg/mL (P = .04). No significant changes were seen in the other neuropeptides, neurotrophins, or cytokines tested. Nasal obstruction, nasal itch, sneezing, runny nose, eye itch, and unrefreshed sleep improved significantly in the real acupuncture group (postnasal drip and sinus pain did not) and continued to improve up to 4-week follow-up.

CONCLUSION

Acupuncture modulated mucosal immune response in the upper airway in adults with persistent allergic rhinitis. This modulation appears to be associated with down-regulation of allergen specific IgE for house dust mite, which this study is the first to report. Improvements in nasal itch, eye itch, and sneezing after acupuncture are suggestive of down-regulation of transient receptor potential vanilloid 1.

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry Identifier: ACTRN 12610001052022.

Local Effect of Neurotrophin-3 in Neuronal Inflammation of Allergic Rhinitis: Preliminary Report

BACKGROUND

Allergic rhinitis is a common inflammatory nasal mucosal disease characterized by sneezing, watery nasal discharge, nasal obstruction and itching. Although allergen-specific antibodies play a main role in the allergic airway inflammation, neuronal inflammation may also contribute to the symptoms of allergic rhinitis. Neuronal inflammation is primarily caused by the stimulation of sensory nerve endings with histamine. It has been shown that neurotrophins may also have a role in allergic reactions and neuronal inflammation. Nerve growth factor, neurotrophin 3 (NT-3), neurotrophin 4/5 and brain-derived neurotrophic factor are members of the neurotrophin family. Although nerve growth factor and brain-derived neurotrophic factor are well studied in allergic rhinitis patients, the exact role of Neurotrophin-3 is not known.

AIMS

To investigate the possible roles of neurotrophin-3 in allergic rhinitis patients.

STUDY DESIGN

Case-control study.

METHODS

Neurotrophin-3 levels were studied in the inferior turbinate and serum samples of 20 allergic rhinitis and 13 control patients. Neurotrophin-3 staining of nasal tissues was evaluated by immunohistochemistry and ELISA was used for the determination of serum Neurotrophin-3 levels.

RESULTS

Neurotrophin-3 staining scores were statistically higher in the study group than in the control patients (p=0.001). Regarding serum Neurotrophin-3 levels, no statistically significant difference could be determined between allergic rhinitis and control patients (p=0.156). When comparing the serum NT-3 levels with tissue staining scores, there were no statistically significant differences in the allergic rhinitis and control groups (p=0.254 for allergic rhinitis and p=0.624 for control groups).

CONCLUSION

We suggest that Neurotrophin-3 might affect the nasal mucosa locally without being released into the systemic circulation in allergic rhinitis patients.

Effect of the TRPV1 antagonist SB-705498 on the nasal parasympathetic reflex response in the ovalbumin sensitized guinea pig

BACKGROUND AND PURPOSE

Nasal sensory nerves play an important role in symptoms associated with rhinitis triggered by environmental stimuli. Here, we propose that TRPV1 is pivotal in nasal sensory nerve activation and assess the potential of SB-705498 as an intranasal therapy for rhinitis.

EXPERIMENTAL APPROACH

The inhibitory effect of SB-705498 on capsaicin-induced currents in guinea pig trigeminal ganglion cells innervating nasal mucosa was investigated using patch clamp electrophysiology. A guinea pig model of rhinitis was developed using intranasal challenge of capsaicin and hypertonic saline to elicit nasal secretory parasympathetic reflex responses, quantified using MRI. The inhibitory effect of SB-705498, duration of action and potency comparing oral versus intranasal route of administration were examined.

KEY RESULTS

SB-705498 concentration-dependently inhibited capsaicin-induced currents in isolated trigeminal ganglion cells (pIC50 7.2). In vivo, capsaicin ipsilateral nasal challenge (0.03-1 mM) elicited concentration-dependent increases in contralateral intranasal fluid secretion. Ten per cent hypertonic saline initiated a similar response. Atropine inhibited responses to either challenge. SB-705498 inhibited capsaicin-induced responses by ∼50% at 10 mg·kg⁻¹ (oral), non-micronized 10 mg·mL⁻¹ or 1 mg·mL⁻¹ micronized SB-705498 (intranasal) suspension. Ten milligram per millilitre intranasal SB-705498, dosed 24 h prior to capsaicin challenge produced a 52% reduction in secretory response. SB-705498 (10 mg·mL⁻¹, intranasal) inhibited 10% hypertonic saline responses by 70%.

CONCLUSIONS AND IMPLICATIONS

The paper reports the development of a guinea pig model of rhinitis. SB-705498 inhibits capsaicin-induced trigeminal currents and capsaicin-induced contralateral nasal secretions via oral and intranasal routes; efficacy was optimized using particle-reduced SB-705498. We propose that TRPV1 is pivotal in initiating symptoms of rhinitis.

Kinetic oscillation stimulation as treatment of non-allergic rhinitis: an RCT study

CONCLUSION

Kinetic oscillation stimulation (KOS) of nasal mucosa at low frequency seems to be a possibly effective and safe short-term treatment of non-allergic nasal stuffiness.

OBJECTIVE

To assess the relief of rhinitis symptoms, especially stuffiness, by comparing active treatment, i.e. KOS at low frequency of the nasal mucosa, with placebo.

METHODS

Patients were randomized to active or placebo treatment in this double-blinded parallel design study. Treatment with an inflatable oscillating catheter was administered on day 0, and symptom scores (stuffiness, secretion, and itching) were graded daily until day 14. An overall grading of symptoms from 1 week before treatment and during 14 days thereafter was made at day 14. Eighty-six patients (52 with non-allergic perennial rhinitis, NAR; 34 with rhinitis medicamentosa, RM) were randomized, and 71 were evaluated (active treatment, n = 35; placebo, n = 36).

RESULTS

Patients with either NAR or RM who received active treatment reported reduced symptom scores by some measures, e.g. median RQSS stuffiness measure fell from 2 to 1 on a scale from 0 to 3 during the week following treatment. No significant effect was observed for patients treated with placebo. Mild side effects were reported.

Coordination of breathing with nonrespiratory activities

Many articles in this section of Comprehensive Physiology are concerned with the development and function of a central pattern generator (CPG) for the control of breathing in vertebrate animals. The action of the respiratory CPG is extensively modified by cortical and other descending influences as well as by feedback from peripheral sensory systems. The central nervous system also incorporates other CPGs, which orchestrate a wide variety of discrete and repetitive, voluntary and involuntary movements. The coordination of breathing with these other activities requires interaction and coordination between the respiratory CPG and those governing the nonrespiratory activities. Most of these interactions are complex and poorly understood. They seem to involve both conventional synaptic crosstalk between groups of neurons and fluid identity of neurons as belonging to one CPG or another: neurons that normally participate in breathing may be temporarily borrowed or hijacked by a competing or interrupting activity. This review explores the control of breathing as it is influenced by many activities that are generally considered to be nonrespiratory. The mechanistic detail varies greatly among topics, reflecting the wide variety of pertinent experiments.

Brazilian Academy of Rhinology position paper on topical intranasal therapy

This documents aims at educating those who treat sinonasal diseases - both general practitioners and specialists - about topical nasal treatments. By means of scientific evidence reviews, the Brazilian Academy of Rhinology provides its practical and updated guidelines on the most utilized topical nasal medication, except for the drugs that have topical antibiotics in their formulas.

The anti-inflammatory effects of acupuncture and their relevance to allergic rhinitis: a narrative review and proposed model

Classical literature indicates that acupuncture has been used for millennia to treat numerous inflammatory conditions, including allergic rhinitis. Recent research has examined some of the mechanisms underpinning acupuncture's anti-inflammatory effects which include mediation by sympathetic and parasympathetic pathways. The hypothalamus-pituitary-adrenal (HPA) axis has been reported to mediate the antioedema effects of acupuncture, but not antihyperalgesic actions during inflammation. Other reported anti-inflammatory effects of acupuncture include an antihistamine action and downregulation of proinflammatory cytokines (such as TNF-α, IL-1β, IL-6, and IL-10), proinflammatory neuropeptides (such as SP, CGRP, and VIP), and neurotrophins (such as NGF and BDNF) which can enhance and prolong inflammatory response. Acupuncture has been reported to suppress the expression of COX-1, COX-2, and iNOS during experimentally induced inflammation. Downregulation of the expression and sensitivity of the transient receptor potential vallinoid 1 (TRPV1) after acupuncture has been reported. In summary, acupuncture may exert anti-inflammatory effects through a complex neuro-endocrino-immunological network of actions. Many of these generic anti-inflammatory effects of acupuncture are of direct relevance to allergic rhinitis; however, more research is needed to elucidate specifically how immune mechanisms might be modulated by acupuncture in allergic rhinitis, and to this end a proposed model is offered to guide further research.

Heart rate variability analysis in patients with allergic rhinitis

BACKGROUND

Very few studies investigate the role of the autonomic nervous system in allergic rhinitis. In this study, we evaluated the autonomic nervous system in allergic rhinitis patients using heart rate variability (HRV) analysis.

METHODS

Eleven patients with allergic rhinitis and 13 healthy controls, aged between 19 and 40 years old, were enrolled in the study. Diagnosis of allergic rhinitis was based on clinical history, symptoms, and positive Phadiatop test. Electrocardiographic recordings on the sitting and supine positions were obtained for HRV analysis.

RESULTS

In the supine position, there were no significant statistical differences in very-low-frequency power (VLF, ≤0.04 Hz), low-frequency power (LF, 0.04-0.15 Hz), high-frequency power (HF, 0.15-0.40 Hz), and the ratio of LF to HF (LF/HF) between the patient and control groups. The mean RR intervals significantly increased, while LF% and LF/HF significantly decreased in the patient group in the sitting position. Moreover, mean RR intervals, LF, and LF/HF, which were significantly different between the two positions in the control group, did not show a significant change with the posture change in the patient group.

CONCLUSION

These suggest that patients with allergic rhinitis may have poor sympathetic modulation in the sitting position. Autonomic dysfunction may therefore play a role in the pathophysiology of allergic rhinitis.

Autonomic neural control of the airways

The airways and lungs are innervated by both sympathetic and parasympathetic nerves. Cholinergic parasympathetic innervation is well conserved in the airways while the distribution of noncholinergic parasympathetic and adrenergic sympathetic nerves varies considerably amongst species. Autonomic nerve function is regulated primarily through reflexes initiated upon bronchopulmonary vagal afferent nerves. Central regulation of autonomic tone is poorly described but some key elements have been defined.

Occupational rhinitis induced by capsaicin

Capsaicin is the spice component of red pepper. It can be easily inhaled, inducing a reproducible cough and provokes a secretory response from the human nasal mucosa. To date, there has been no report of occupational rhinitis (OR) caused by capsaicin. We report the case of a 44-year-old female mill worker who developed occupational rhinitis after 4 years of exposure to capsaicin. She developed nasal congestion, rhinorrhea, and itchy nose, which were all aggravated upon exposure at the workplace. The patient had negative responses to all common inhalant allergens, including capsaicin, by skin prick tests. The nasal provocation test with capsaicin showed that the nasal symptom score and eosinophil count increased 10 minutes after the provocation and decreased after 1 to 3 hours; no significant response was noted to house dust mite allergen. The patient's work-related rhinitis improved 1 month after she relocated and started pharmacological treatment. To our knowledge, this is the first case of OR caused by capsaicin exposure in the workplace. We provide evidence suggesting that OR may be mediated by a non-immunological mechanism.

New developments in the use of histamine and histamine receptors

Histamine and the histamine receptors are important regulators of a plethora of biological processes, including immediate hypersensitivity reactions and acid secretion in the stomach. In these roles, antihistamines have found widespread therapeutic applications, while the last receptor to be discovered, the H4 histamine receptor, has become a major target of novel therapeutics. Recent studies involving human genetic variance and the development of mice lacking specific receptors or the ability to generate histamine have shown roles for the histamine pathway that extend well beyond the established roles. These include identification of previously unappreciated mechanisms through which histamine regulates inflammation in allergy, as well as roles in autoimmunity, infection, and pain. As a result, antihistamines may have wider applications in the future than previously predicted.

Management of rhinitis: allergic and non-allergic

RHINITIS IS A GLOBAL PROBLEM AND IS DEFINED AS THE PRESENCE OF AT LEAST ONE OF THE FOLLOWING: congestion, rhinorrhea, sneezing, nasal itching, and nasal obstruction. The two major classifications are allergic and nonallergic rhinitis (NAR). Allergic rhinitis occurs when an allergen is the trigger for the nasal symptoms. NAR is when obstruction and rhinorrhea occurs in relation to nonallergic, noninfectious triggers such as change in the weather, exposure to caustic odors or cigarette smoke, barometric pressure differences, etc. There is a lack of concomitant allergic disease, determined by negative skin prick test for relevant allergens and/or negative allergen-specific antibody tests. Both are highly prevalent diseases that have a significant economic burden on society and negative impact on patient quality of life. Treatment of allergic rhinitis includes allergen avoidance, antihistamines (oral and intranasal), intranasal corticosteroids, intranasal cromones, leukotriene receptor antagonists, and immunotherapy. Occasional systemic corticosteroids and decongestants (oral and topical) are also used. NAR has 8 major subtypes which includes nonallergic rhinopathy (previously known as vasomotor rhinitis), nonallergic rhinitis with eosinophilia, atrophic rhinitis, senile rhinitis, gustatory rhinitis, drug-induced rhinitis, hormonal-induced rhinitis, and cerebral spinal fluid leak. The mainstay of treatment for NAR are intranasal corticosteroids. Topical antihistamines have also been found to be efficacious. Topical anticholinergics such as ipratropium bromide (0.03%) nasal spray are effective in treating rhinorrhea symptoms. Adjunct therapy includes decongestants and nasal saline. Investigational therapies in the treatment of NAR discussed include capsaicin, silver nitrate, and acupuncture.

Capsaicin-induced vasodilatation in human nasal vasculature is mediated by modulation of cyclooxygenase-2 activity and abrogated by sulprostone

Extensively based on evidence gained from experimental animal models, the transient receptor potential vanilloid receptor type 1 (TRPV1)-activator capsaicin is regarded as a valuable tool in the research on neurogenic inflammation. Although capsaicin-related drugs gained renewed interest as a therapeutic tool, there is also controversy as whether neurogenic inflammation actually takes place in humans. In this study, we verified the involvement of capsaicin in vascular responses that are regarded to be implicated in the cascade of neurogenic inflammatory mechanisms. By means of ex vivo functional experiments on human nasal mucosal vascular beds, the effect and mechanism of action of capsaicin was assessed in the absence and presence of various agents that interfere with potentially related transduction pathways. Ten micromolars of capsaicin induced vasodilatations that were reduced by the selective EP(1) prostanoid receptor antagonist SC19220 (10 μM) and almost abolished by the selective COX-2 inhibitor NS398 (1 μM) and the EP(1/3) receptor agonist sulprostone (0.1-10 nM), but not affected by the TRPV1-antagonists capsazepine (5 μM), the neurokinin NK(1) receptor antagonist GR20517A (1 μM), and the calcitonin-gene-related peptide (CGRP) receptor antagonist CGRP8-37 (100 nM). Spontaneously released PGE(2) and PGD(2) levels were significantly reduced in the presence of capsaicin. In conclusion, capsaicin-at concentrations clinically applied or under investigation for diverse disease backgrounds-induces a vasodilatory response in human nasal mucosa via a mechanism involving TRPV1-independent reduction of PGE(2) production by modulation of COX-2 enzymatic activity. These vasodilatations can be suppressed by the EP(1/3) receptor agonist sulprostone at subnanomolar concentrations.

Role of muscarinic receptor activation in regulating immune cell activity in nasal mucosa

BACKGROUND

The prevalence of airway inflammatory disorders keeps rising; its pathogenic mechanism is still not fully understood.

OBJECTIVE

The present study aimed to investigate the role of muscarinic receptor (M receptor) in regulating the immune cell activity in nasal mucosa by using surgical removed nasal mucosa from patients with nasal polyposis (NP) as a study platform.

METHODS

Human nasal mucosal sample was collected from inferior turbinectomy of 86 patients with NP or/and allergic rhinitis. Expression of tumor necrosis factor alpha (TNF-alpha), M receptor, OX40 ligand was measured in nasal mucosa by enzyme-linked immunosorbent assay, flow cytometry, and Western blotting assay.

RESULTS

When compared with non-NP (nNP) nasal mucosa, contents of TNF-alpha and TNF-alpha+ cells markedly increased in NP nasal mucosa; immune staining colocalized M3 receptor+ and TNF-alpha+ cells in NP nasal mucosa; exposure of isolated CD4+ T cells to methacholine induced the release of TNF-alpha. We also found CD11c+/M3 receptor+ cells in NP nasal mucosa. Methacholine increased the expression of OX40L in dendritic cells. Staphylococcal (S) aureus and S. enterotoxin B (SEB) were detected in NP nasal mucosa. Exposure of dendritic cells or naïve CD4+ T cells to SEB initiated the expression of M3 receptor at mRNA and protein levels.

CONCLUSIONS

The present data demonstrate that parasympathetic activity has the capacity to activate dendritic cells to release OX40 ligand, the latter induces CD4+ T cells to produce IL-4 and TNF-alpha that may further contribute to the pathogenesis of NP.

Sneeze reflex: facts and fiction

Sneezing is a protective reflex, and is sometimes a sign of various medical conditions. Sneezing has been a remarkable sign throughout the history. In Asia and Europe, superstitions regarding sneezing extend through a wide range of races and countries, and it has an ominous significance. Although sneezing is a protective reflex response, little else is known about it. A sneeze (or sternutation) is expulsion of air from the lungs through the nose and mouth, most commonly caused by the irritation of the nasal mucosa. Sneezing can further be triggered through sudden exposure to bright light, a particularly full stomach and physical stimulants of the trigeminal nerve, as a result of central nervous system pathologies such as epilepsy, posterior inferior cerebellar artery syndrome or as a symptom of psychogenic pathologies. In this first comprehensive review of the sneeze reflex in the English literature, we aim to review the pathophysiology, etiology, diagnosis, treatment and complications of sneezing.

Important research questions in allergy and related diseases: nonallergic rhinitis: a GA2LEN paper

Nonallergic rhinitis (NAR) can be defined as a chronic nasal inflammation which is not caused by systemic IgE-dependent mechanisms. It is common and probably affects far more than 200 million people worldwide. Both children and adults are affected. However, its exact prevalence is unknown and its phenotypes need to be evaluated using appropriate methods to better understand its pathophysiology, diagnosis and management. It is important to differentiate between infectious rhinitis, allergic/NAR and chronic rhinosinusitis, as management differs for each of these cases. Characterization of the phenotype, mechanisms and management of NAR represents one of the major unmet needs in allergic and nonallergic diseases. Studies on children and adults are required in order to appreciate the prevalence, phenotype, severity and co-morbidities of NAR. These studies should compare allergic and NAR and consider different age group populations including elderly subjects. Mechanistic studies should be carried out to better understand the disease(s) and risk factors and to guide towards an improved diagnosis and therapy. These studies need to take the heterogeneity of NAR into account. It is likely that neuronal mechanisms, T cells, innate immunity and possibly auto-immune responses all play a role in NAR and may also contribute to the symptoms of allergic rhinitis.