Tryptase and histamine as markers to evaluate mast cell activation during the responses to nasal challenge with allergen, cold, dry air, and hyperosmolar solutions

Learned cautions regarding antibody testing in mast cell activation syndrome

OBJECTIVES

To describe patterns observed in antibody titer trendlines in patients with mast cell activation syndrome (MCAS, a prevalent but underrecognized chronic multisystem inflammatory disorder of great clinical heterogeneity) and offer clinical lessons learned from such pattern recognition.

METHODS

The available records of 104 MCAS patients drawn from the authors' practices were reviewed, including all antibody tests therein.

RESULTS

All patients had positive/elevated antibodies of various sorts at various points, but for most of the antibodies which were found to be positive at least some points, the diseases classically associated with those antibodies were not present, marking such antibodies as clinically insignificant mimickers (likely consequent to inflammatory effects of MCAS on the immune system itself driving spurious/random antibody production) rather than "on-target" and pathogenic antibodies reflecting true disease warranting treatment. We also observed two distinct patterns in trendlines of the titers of the mimickers vs. the trendline pattern expected in a true case of an antibody-associated disease (AAD).

CONCLUSIONS

Our observations suggest most positive antibody tests in MCAS patients represent detection of clinically insignificant mimicking antibodies. As such, to reduce incorrect diagnoses of AADs and inappropriate treatment in MCAS patients, caution is warranted in interpreting positive antibody tests in these patients. Except in clinically urgent/emergent situations, patience in determining the trendline of a positive antibody in an MCAS patient, and more carefully assessing whether the AAD is truly present, is to be preferred.

Human C1q Tumor Necrosis Factor 8 (CTRP8) defines a novel tryptase+ mast cell subpopulation in the prostate cancer microenvironment

The adipokine C1q Tumor Necrosis Factor 8 (CTRP8) is the least known member of the 15 CTRP proteins and a ligand of the relaxin receptor RXFP1. We previously demonstrated the ability of the CTRP8-RXFP1 interaction to promote motility, matrix invasion, and drug resistance. The lack of specific tools to detect CTRP8 protein severely limits our knowledge on CTRP8 biological functions in normal and tumor tissues. Here, we have generated and characterized the first specific antiserum to human CTRP8 which identified CTRP8 as a novel marker of tryptase+ mast cells (MC_T) in normal human tissues and in the prostate cancer (PC) microenvironment. Using human PC tissue microarrays composed of neoplastic and corresponding tumor-adjacent prostate tissues, we have identified a significantly higher number of CTRP8+ MC_T in the peritumor versus intratumor compartment of PC tissues of Gleason scores 6 and 7. Higher numbers of CTRP8+ MC_T correlated with the clinical parameter of biochemical recurrence. We showed that the human MC line ROSA^{KIT WT} expressed RXFP1 transcripts and responded to CTRP8 treatment with a small but significant increase in cell proliferation. Like the cognate RXFP1 ligand RLN-2 and the small molecule RXFP1 agonist ML-290, CTRP8 reduced degranulation of ROSA^{KIT WT} MC stimulated by the Ca²⁺-ionophore A14187. In conclusion, this is the first report to identify the RXFP1 agonist CTRP8 as a novel marker of MC_T and autocrine/paracrine oncogenic factor within the PC microenvironment.

Mast Cells Trigger Disturbed Bone Healing in Osteoporotic Mice

Mast cells are important tissue-resident sensor and effector immune cells but also play a major role in osteoporosis development. Mast cells are increased in numbers in the bone marrow of postmenopausal osteoporotic patients, and mast cell-deficient mice are protected from ovariectomy (OVX)-induced bone loss. In this study, we showed that mast cell-deficient Mcpt5-Cre R-DTA mice were protected from OVX-induced disturbed fracture healing, indicating a critical role for mast cells in the pathomechanisms of impaired bone repair under estrogen-deficient conditions. We revealed that mast cells trigger the fracture-induced inflammatory response by releasing inflammatory mediators, including interleukin-6, midkine (Mdk), and C-X-C motif chemokine ligand 10 (CXCL10), and promote neutrophil infiltration into the fracture site in OVX mice. Furthermore, mast cells were responsible for reduced osteoblast and increased osteoclast activities in OVX mice callus, as well as increased receptor activator of NF-κB ligand serum levels in OVX mice. Additional in vitro studies with human cells showed that mast cells stimulate osteoclastogenesis by releasing the osteoclastogenic mediators Mdk and CXCL10 in an estrogen-dependent manner, which was mediated via the estrogen receptor alpha on mast cells. In conclusion, mast cells negatively affect the healing of bone fractures under estrogen-deficient conditions. Hence, targeting mast cells might provide a therapeutic strategy to improve disturbed bone repair in postmenopausal osteoporosis. © 2021 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Comparison of allergens and symptoms in patients with allergic rhinitis between 1990s and 2010s

Background

The prevalence of allergic rhinitis (AR), an environment- and lifestyle-dependent condition, has been constantly increasing in Korea. Although the environment and lifestyle of the Korean people have recently undergone rapid changes, corresponding changes in the characteristics of AR patients have not been well documented. Therefore, we aimed to outline the changes in allergens and clinical manifestations of AR in Korean patients from the 1990s and 2010s.

Methods

We reviewed 1447 and 3388 AR patients who visited the same tertiary hospital in the 1990s and 2010s, respectively. All patients were diagnosed with AR based on the presence of characteristic symptoms, positive skin prick test results, and answered a symptom questionnaire at the time of visit. We compared differences in the allergens and results of the symptom questionnaire between the two sets of patients.

Results

When compared with the 1990s, the rate of sensitization to house dust mites, cockroaches, Aspergillus, Alternaria, and tree pollen significantly increased and that to cat fur significantly decreased in patients from the 2010s (all P < 0.05). Male predominance was observed with two peaks in the age distribution of patients from the 2010s. The proportion of patients with moderate-to-severe nasal obstruction and itching of the nose/eye increased (each P < 0.05) and that of patients with minor symptoms such as olfactory disturbances, cough, sore throat, and fatigue also increased (all P < 0.01) in the 2010s.

Conclusions

Allergen reactivity and type and symptom severity in Korean AR patients significantly varied between the 1990s and 2010s. Our results may therefore be helpful for patient counseling and management.

Incidence of the Acute Symptom of Chronic Periodontal Disease in Patients Undergoing Supportive Periodontal Therapy: A 5-Year Study Evaluating Climate Variables

Although patients under supportive periodontal therapy (SPT) have a stable periodontal condition, the acute symptom of chronic periodontal disease occasionally occurs without a clear reason. Therefore, in the present study, to obtain a better understanding of this relationship in patients undergoing SPT, we hypothesized that the acute symptom of chronic periodontal disease might be affected by climate factors. We conducted a questionnaire study and carried out oral examinations on patients undergoing SPT who had been diagnosed as having the acute symptom of chronic periodontal disease. We collected climate data from the local climate office in Okayama city, Japan. We predicted parameters that affect the acute symptom of chronic periodontal disease with unidentified cause and divided patients into high and low groups in terms of climate predictors. Then we defined the cut-off values of parameters showing significant differences in the incidence of the acute symptom of chronic periodontal disease. The incidence of the acute symptom of chronic periodontal disease with unidentified cause was significantly different when the cases were classified according to the maximum hourly decrease in barometric pressure (1.5 and 1.9 hPa) (p = 0.04 and p = 0.03, respectively). This suggests that climate variables could be predictors of the acute symptom of chronic periodontal disease. Therefore, gaining a better understanding of these factors could help periodontal patients undergoing SPT prepare to avoid the acute symptom of chronic periodontal disease.

Immunological response to bacterial infection in a pelagic tunicate: Inflammation in the salp Thalia democratica

Thaliaceans are pelagic tunicates that play a key role in trophic chains of the oceans. In the field of tunicate immunity, a notable gap is the lack of data on their inflammatory response. The common salp, Thalia democratica, possesses scant immunocytes, represented by a phagocytic line (hyaline amebocytes) and a mast cell-like line (granular cells). We aimed to provide the first investigation of defense reactions upon exposure to a large amount of bacteria (Bacillus clausii). We detected (i) bacterial phagocytosis by hyaline amebocytes, (ii) degradation of phagocytizing hyaline amebocytes in the tunic after transcellular diapedesis from the hemocoel, and (iii) release of heparin, histamine, and TNF-α by granular cells. Cell degranulation and phagocytosis occurred in epidermal cells lining the hemocoel, and an excess of mucus was observed in the post-branchial gut, causing a functional inhibition of cilia and microvilli. These findings indicate multi-step events comparable to an inflammation involving responses at both tissue and organismal levels.

The association between local meteorological changes and exacerbation of acute wheezing in Kandy, Sri Lanka

BACKGROUND

Severe wheezing is a common medical emergency. Past studies have demonstrated associations between exacerbation of wheezing and meteorological factors and atmospheric pollution. There are no past studies from Sri Lanka that analyzed correlation between daily multiple meteorological variables and exacerbation of wheezing.

OBJECTIVES

To determine the correlations between daily counts of patients nebulized at the Outpatient Department (OPD) of Teaching Hospital - Kandy (THK) and local meteorological variables, and to explore the utility of that information.

DESIGN

We considered daily counts of patients nebulized at the OPD of THK as an indicator of exacerbations of wheezing in the population catered to by this hospital. We determined the correlations between daily counts of patients nebulized at OPD and the following meteorological variables for four years: daily rainfall, minimum temperature, maximum temperature, diurnal temperature range, difference between maximum temperature and the temperature at 1800 hours, daytime humidity, nighttime humidity, barometric pressure and visibility. We utilized wavelet time series method for data analysis.

RESULTS

All nine meteorological parameters studied were correlated with the daily counts of patients nebulized with average lag periods ranging from 5 to 15 days. Peaks of daily rainfall, maximum temperature, diurnal temperature range, difference between maximum temperature and the temperature at 1800 hours and daytime humidity were followed by peaks of counts of patients nebulized (positive correlations). Troughs of minimum temperature, nighttime humidity, barometric pressure and visibility were followed by peaks of patients nebulized (negative correlations).

CONCLUSIONS

The THK shall expect more patients with acute wheezing after extremes of weather. Minimum temperature has been consistently correlated with the exacerbation of respiratory symptoms in the past studies in other countries as well. Hence, prescribing the inhalation of more drugs on unusually cold days (prophylactically) may help prevent acute exacerbation of wheezing in patients on treatment for asthma and COPD.

β-eudesmol suppresses allergic reactions via inhibiting mast cell degranulation

The regulatory effect of β-eudesmol, which is an active constituent of Pyeongwee-San (KMP6), is evaluated for allergic reactions induced by mast cell degranulation. Phorbol 12-myristate 13-acetate (PMA) plus calcium ionophore A23187-stimulated human mast cell line, HMC-1 cells, and compound 48/80-stimulated rat peritoneal mast cells (RPMCs) are used as the in vitro models; mice models of systemic anaphylaxis, ear swelling, and IgE-dependent passive cutaneous anaphylaxis (PCA) are used as the in vivo allergic models. The results demonstrate that β-eudesmol suppressed the histamine and tryptase releases from the PMA plus calcium ionophore A23187-stimulated HMC-1 cells. β-eudesmol inhibits the expression and activity of histidine decarboxylase in the activated HMC-1 cells. In addition, β-eudesmol inhibits the levels of histamine and tryptase released from the compound 48/80-stimulated RPMCs. Furthermore, β-eudesmol decreases the intracellular calcium level in the activated RPMCs. β-eudesmol also decreases the compound 48/80-induced mortality and ear swelling response. β-eudesmol suppresses the serum levels of histamine, IgE, interleukin (IL)-1β, IL-4, IL-5, IL-6, IL-13, and vascular endothelial growth factor (VEGF) under PCA mice as well as PCA reactions. Therefore, the results from this study indicate the potential of β-eudesmol as an anti-allergic drug with respect to its pharmacological properties against mast cell-mediated allergic reactions.

Effect of malonaldehyde cross-linking on the ability of shrimp tropomyosin to elicit the release of inflammatory mediators and cytokines from activated RBL-2H3 cells

BACKGROUND

Malonaldehyde, the primary by-product of lipid peroxidation in food, modifies the structural and functional properties of proteins by cross-linking. The aim of this study was to investigate the effect of malonaldehyde on the allergenicity of shrimp tropomyosin.

RESULTS

RBL-2H3 cells, a model of type I allergic reactions, were sensitised with sera from patients allergic to shrimp, and were stimulated with native and cross-linked tropomyosin. Release of inflammatory mediators such as β-hexosaminidase, histamine, tryptase, cysteinyl leukotriene, and prostaglandin D2 was clearly suppressed in a manner that depended on the extent of tropomyosin cross-linking. Release of interleukin-4 (IL-4) and IL-13 was similarly decreased. Notably, cells sensitised with one patient's serum released IL-4 at comparable levels in response to native and cross-linked tropomyosin.

CONCLUSION

Cross-linking strongly modulates the ability of shrimp tropomyosin to induce release of inflammatory cytokines and mediators from activated RBL-2H3 cells. © 2016 Society of Chemical Industry.

Rapid allergen inactivation using atmospheric pressure cold plasma

Allergies have become a global problem, and effective control is greatly needed. Here, the inactivation effects of the atmospheric pressure cold plasma (APCP) on aerosolized allergens including Der p 1, Der f 1, Asp f 1, Alt a 1, and Can f 1 as well as those from indoor and outdoor environments were investigated. The effectiveness of the APCP treatment was further studied using blood sera from the allergen sensitized humans. In addition, the allergen samples were also analyzed using sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Results revealed that the APCP was highly effective in reducing the allergenicity of both lab-prepared and environmental allergen aerosols. The airborne reductions were shown to range from 30% for Der p 1 to 80% for Can f 1 allergen for 0.12 s exposure. Allergnicity tests showed that the APCP treated Asp f 1 allergens caused 50% less binding with IgEs in the blood sera compared to the control. The observed allergenicity loss was due to hydroxyl radicals produced by the plasma device. The results from SDS-PAGE showed that the plasma treatment resulted in decreased size of the Asp f 1 allergen. The developed technology holds great promise in combating the allergic diseases.

Differential diagnosis in allergy

The otolaryngic allergist must be able to distinguish between common nonallergic diagnoses that present very similarly to allergic conditions. This article describes a few of the vast myriad of conditions that must be ruled out before a diagnosis of allergy may be made. After reading this article clinicians will be able to identify various conditions, which will enhance their ability to appropriately make correct decisions for prompt and efficient management of their patients with allergic or nonallergic diseases of the head and neck.

Mast cells drive mesenteric afferent signalling during acute intestinal ischaemia

Acute intestinal ischaemia stimulates visceral afferent nerves but the mechanisms responsible for this excitation are not fully understood. Mast cells may participate in this process as they are known to signal to mesenteric afferents during intestinal anaphylaxis and contribute to early inflammation and neuronal damage in response to cerebral ischaemia. We therefore hypothesised that mast cells are early responders to acute intestinal ischaemia and their activation initiates rapid signalling to the CNS via the excitation of mesenteric afferents. Primary afferent firing was recorded from a mesenteric nerve bundle supplying a segment of jejunum in anaesthetized adult rats. Acute focal ischaemia was produced by clamping theme senteric vessels for 8 min, and reperfusion followed removal of the vessel clip. Two episodes of ischaemia–reperfusion (I–R) separated by a 30 min interval were performed. Drugs or their vehicles were administered 10 min before the 2nd I–R episode. Ischaemia caused a reproducible, intense and biphasic afferent firing that was temporally dissociated from the concomitantly triggered complex pattern of intestinal motor activity. The L-type calcium channel blocker, nifedipine, significantly attenuated this afferent firing by a mechanism independent of its action on intestinal tone. Ischaemia-induced afferent firing was also abrogated by the mast cell stabilizer, doxantrazole, and the H1 histamine receptor antagonist, pyrilamine. In contrast, the nicotinic receptor antagonist, hexamethonium, and the N-type calcium channel toxin, ω-conotoxin GVIA, each reduced the ischaemia-evoked motor inhibition but not the concurrent afferent discharge. Similarly, the cyclooxygenase inhibitor, naproxen, had no effect on the ischaemic afferent response but reduced the intestinal tone shortly from the onset of ischaemia to the early period of reperfusion. These data support a critical role for mast cell-derived histamine in the direct chemoexcitation of mesenteric afferents during acute intestinal ischaemia, whereas enteric reflex mechanisms and cyclooxygenase products contribute primarily to ischaemia-induced changes in intestinal motility. Therefore, targeting mast cells may provide benefits in patients with abdominal pain resulting from an ischaemic insult to the gastrointestinal tract.

Exposure assessment in Beijing, China: biological agents, ultrafine particles, and lead

In this study, air samples were taken using a BioSampler and gelatin filters from six sites in Beijing: office, hospital, student dormitory, train station, subway, and a commercial street. Dust samples were also collected using a surface sampler from the same environments. Limulus amoebocyte lysate (LAL) and Glucatell assays were used to quantify sample endotoxin and (1,3)-β-d-glucan concentration levels, respectively. Enzyme-linked immunosorbent assay (ELISA) was used to measure the dust mite allergens (Der p 1 and Der f 1). Ultrafine particle and lead concentrations in these sampling sites were also measured using P-Trak and atomic absorption spectrometer, respectively. Analysis of variance (ANOVA) and linear regression analysis were used to analyze the concentration data. Higher culturable bacteria (12,639 CFU/m3) and fungi (1,806 CFU/m3) concentrations were observed for the train station and the subway system, respectively. For the rest of sampling sites, their concentrations were comparable to those found in western countries, ranging from 990 to 2,276 CFU/m3 for bacteria, and from 119 to 269 CFU/m3 for fungi. ANOVA analysis indicated that there were statistically significant differences between the culturable bacterial and fungal concentration levels obtained for different sites (p value=0.0001 and 0.0047). As for dust allergens, endotoxin, and (1,3)-β-D-glucan, their concentrations also seemed to be comparable to those found in the developed countries. Airborne allergen concentrations ranged from 16 to 68 ng/m3. The dust-borne allergen concentration was observed to range from 0.063 to 0.327 ng/mg. As for endotoxin, the highest airborne concentration of 25.24 ng/m3 was observed for the commercial street, and others ranged from 0.0427 to 0.1259 ng/m3. And dust-borne endotoxin concentration ranged from 58.83 to 6,427.4 ng/mg. For (1,3)-β-D-glucan, the airborne concentration ranged from 0.02 to 1.2 ng/m3. Linear regression analyses showed that there existed poor correlations between those in airborne and dust-borne states (R2=0.002~0.43). In our study, the lowest ultrafine particle concentration about 5,203 pt/cm3 was observed in office and the highest was observed at the train station, up to 32,783 pt/cm3. Lead concentration was shown to range from 80 to 170 ng/mg with the highest also observed at the train station. The information provided in this work can be used to learn the general situation of relevant health risks in Beijing. And the results here suggested that when characterizing exposure both airborne and dust-borne as well as the environments should be considered.

Autism spectrum disorders and allergy: observation from a pediatric allergy/immunology clinic

IgE-mediated allergic diseases (e.g., allergic rhinoconjunctivitis, atopic asthma and food allergy) are prevalent (up to 30%) in the general population and are increasing in developed countries. In infants and young children, non-IgE-mediated food allergy is also prevalent. In addition to easily recognized organ-specific symptoms, allergic diseases can cause neuropsychiatric symptoms, such as irritability and hyperactivity, in otherwise healthy individuals. This is also likely to occur in children with autism spectrum disorder (ASD). Moreover, the discomfort and pain associated with allergic diseases could aggravate behavioral symptoms in ASD children. Allergic conditions are easily treatable; however, ASD children may be underdiagnosed and/or undertreated for allergic and other common childhood diseases, in part due to their impaired communication skills. Practicing physicians should be aware of the potential impact of allergic diseases on behavioral symptoms and cognitive activity in ASD children. However, they also need to be aware that certain symptoms often attributed to 'allergy' by caregivers may not be immune mediated and should understand that behavioral symptoms can also be affected by many non-IgE-mediated causes.

Effects of omalizumab on basophil and mast cell responses using an intranasal cat allergen challenge

BACKGROUND

Omalizumab treatment suppresses FcepsilonRI expression faster on blood basophils than skin mast cells.

OBJECTIVE

We used omalizumab to elucidate the relative contributions of basophil versus mast cell FcepsilonRI activation in a nasal allergen challenge (NAC) model.

METHODS

Eighteen subjects with cat allergy were enrolled in a 3.5-month, double-blind, randomized (3.5:1), placebo-controlled trial of omalizumab using standard dosing. At baseline, subjects underwent NAC with lavage for prostaglandin D(2) measurement, skin prick test titration (SPTT), and blood sampling for basophil histamine release (BHR) and basophil IgE/FcepsilonRI measurements. Basophil studies were repeated at day 3 and then weekly until cat allergen-induced BHR was <20% of baseline or until day 45. Baseline visit procedures were repeated after the BHR reduction (midstudy NAC) and at the treatment period's completion (final NAC).

RESULTS

Subjects treated with omalizumab who completed all NACs (n = 12) demonstrated significant mean reduction in BHR to an optimal dose of cat allergen by midstudy NAC compared with baseline (74% decrease; P = .001). In addition, these subjects demonstrated significant decreases in mean combined nasal symptom scores (50% decrease; P = .007) and total sneeze counts (59% decrease; P = .01) by midstudy NAC relative to baseline NAC. In contrast, measures of mast cell response (SPTT and nasal lavage prostaglandin D(2)) were only significantly reduced by the final NAC. Subjects on placebo (n = 4) did not experience a shift in basophil, NAC symptom, or mast cell measures.

CONCLUSION

Reduction in nasal symptom scores occurred when the basophil, but not mast cell, response was reduced on omalizumab, implicating a role for basophils in the acute NAC response.

The effects of the nasal antihistamines olopatadine and azelastine in nasal allergen provocation

BACKGROUND

Olopatadine, an antihistamine used in allergic conjunctivitis, is under development as a nasal preparation for the treatment of allergic rhinitis.

OBJECTIVES

To evaluate the efficacy of olopatadine in suppressing symptoms and biomarkers of the immediate reaction induced by nasal allergen provocation and to compare olopatadine with azelastine in the same model.

METHODS

The study was approved by the Johns Hopkins University institutional review board, and all subjects gave written consent. We studied 20 asymptomatic subjects with seasonal allergic rhinitis. The study had 2 randomized, double-blind, placebo-controlled, crossover phases that evaluated 2 concentrations of olopatadine, 0.1% and 0.2%. In a third exploratory phase, olopatadine, 0.1%, was compared with topical azelastine, 0.1%, in a patient-masked design. Efficacy variables were the allergen-induced sneezes, other clinical symptoms, and the levels of histamine, tryptase, albumin, lysozyme, and cysteinyl-leukotrienes (third study only) in nasal lavage fluids.

RESULTS

Both concentrations of olopatadine produced significant inhibition of all nasal symptoms, compared with placebo. Olopatadine, 0.1%, inhibited lysozyme levels, but olopatadine, 0.2%, inhibited histamine, albumin, and lysozyme. The effects of olopatadine, 0.1%, were comparable to those of azelastine, 0.1%.

CONCLUSIONS

Olopatadine, at 0.1% and 0.2% concentrations, was effective in suppressing allergen-induced nasal symptoms. At 0.2%, olopatadine provided evidence suggestive of inhibition of mast cell degranulation.

Experimental activation of mast cells and their pharmacological modulation

The activation of mast cells is of pivotal importance in the pathogenesis of allergic conditions. Mast cell activation can provoke rapid increases in microvascular permeability, induce bronchoconstriction after blood flow, stimulate the recruitment and activation of other inflammatory cells, and has come to be associated with the processes of tissue remodeling and fibrosis. Such changes may be mediated by the release of a range of potent mediators of inflammation: preformed in secretory granules, or newly generated, or both. There are major differences in the responsiveness to various stimuli and to pharmacological agents for mast cells from different body compartments. A method is presented here for the purification of mast cells from enzymatically dispersed human tissues. The methods described for the experimental activation of mast cells can be readily adapted to studies with cell lines or mast cells obtained through long-term culture.

Upper airways reactions to cold air

Cold air-induced rhinitis is a common complaint of individuals with chronic allergic or nonallergic rhinitis and those with no chronic nasal disease. It is characterized by rhinorrhea, nasal congestion, and nasal burning that appear within minutes of exposure to cold air and dissipate soon after exposure is terminated. The symptoms of cold-air rhinitis are reproduced experimentally with nasal cold-air provocation. This procedure has shown that nasal mast cell activation and sensory nerve stimulation are associated with the development of nasal symptoms. Sensory nerve activation generates a cholinergic reflex that leads to rhinorrhea; therefore, anticholinergic agents are highly effective in treating cold-air rhinitis. Experimental data suggest that individuals with nasal cold-air sensitivity may have reduced ability to compensate for the water loss that occurs during exposure to cold air. Therefore, the symptoms of cold air-induced rhinitis may reflect the activation of compensatory mechanisms to restore mucosal homeostasis.

The mast cell and allergic diseases: role in pathogenesis and implications for therapy

Mast cells have long been recognized for their role in the genesis of allergic inflammation; and more recently for their participation in innate and acquired immune responses. Mast cells reside within tissues including the skin and mucosal membranes, which interface with the external environment; as well as being found within vascularized tissues next to nerves, blood vessels and glandular structures. Mast cells have the capability of reacting both within minutes and over hours to specific stimuli, with local and systemic effects. Mast cells express the high affinity IgE receptor (FcepsilonRI) and upon aggregation of FcepsilonRI by allergen-specific IgE, mast cells release and generate biologically active preformed and newly synthesized mediators which are involved in many aspects of allergic inflammation. While mast cells have been well documented to be essential for acute allergic reactions, more recently the importance of mast cells in reacting through pattern recognition receptors in innate immune responses has become recognized. Moreover, as our molecular understanding of the mast cell has evolved, novel targets for modulation have been identified with promising therapeutic potential.

Lower respiratory tract complications during nasal provocation: nonspecific stimulant or specific allergen?

BACKGROUND

Allergic rhinitis (AR) is an allergic inflammatory disease in which allergen exposure leads to the appearance of symptoms in sensitized individuals because of histamine liberation from nasal mucosal mast cells. Comorbidity of this disease with allergic asthma is common. Therefore, the one airway one disease theory has been put forward. Lower respiratory tract provocation tests with both nonspecific (methacholine) and specific stimulants (allergen) have yielded positive results in nonasthmatic patients with AR. However, not enough research is available to demonstrate whether there is a response in the lower respiratory tract during nasal provocation tests (NPTs) performed to evaluate only nasal airway in these patients.

OBJECTIVES

To determine if the lower respiratory tract was affected as a result of NPTs with nonspecific and specific stimulants in nonasthmatic patients with AR and to determine the frequency of lower respiratory tract obstruction due to NPT with nonspecific and specific stimulants.

METHODS

Thirty-six participants were enrolled in the study between November 2005 and January 2006 (18 AR patients and 18 healthy control subjects). Patients underwent 2 sessions of NPT. The first session was performed with nasal methacholine as a nonspecific stimulant, and the second session was performed with nasal Olea europaea extract as a specific stimulant. The control group underwent only nonspecific nasal provocation with methacholine. Basal nasal opening and nasal pressures were evaluated spirometrically by rhinomanometric measurements and basal respiratory function tests in both groups before methacholine nasal provocation. Whether or not nasal provocation was achieved, spirometric measurements were performed in all patients and controls after NPTs.

RESULTS

NPTs with methacholine resulted in a similar frequency of nasal provocation in the patient and control groups (P = .63). However, the mean methacholine dose was lower in patients with AR (P = .049). There was a decrease in parameters of asthma, including the ratio of forced expiratory volume in 1 second to forced vital capacity (P = .04), peak expiratory flow (P = .01), and forced expiratory flow between 25% and 75% (P = .004), as a result of NPTs with methacholine in the patient group. However, NPTs with allergen did not cause a change in lower respiratory tract obstruction criteria.

CONCLUSIONS

Lower respiratory tract obstruction can occur after NPTs with nonspecific stimulants; therefore, tests performed with specific allergens can be regarded as safer.

Stronger nasal responsiveness to cold air in individuals with rhinitis and asthma, compared with rhinitis alone

BACKGROUND

We have previously proposed that, compared with rhinitis alone, the constellation of upper and lower airway allergic disease is a manifestation of a more severe form of a syndrome affecting the entire airway. If this is correct, not only the lower, but also the upper airways of patients with asthma and rhinitis should demonstrate more abnormalities compared with patients with rhinitis alone, including higher sensitivity to irritant factors. Objective To test the hypothesis that, a previously well-studied natural nasal stimulus, cold, dry air (CDA), produces a stronger response in subjects with allergic rhinitis (AR) and asthma compared with subjects with AR alone.

METHODS

We performed nasal provocation with CDA on 24 individuals with asthma and rhinitis and 17 with rhinitis alone. Prior to and after the challenge, nasal symptoms were recorded using visual analogue scales and nasal lavages were performed to determine histamine and lysozyme levels.

RESULTS

The two groups reacted differently to CDA: after the challenge, patients with rhinitis and asthma reported significantly higher scores for nasal congestion, rhinorrhea and lacrimation. Also in this group, significant increases in histamine and in lysozyme levels in nasal lavage fluids were induced by CDA. In subjects with rhinitis alone, CDA failed to increase histamine or lysozyme levels above baseline. The CDA-induced change from baseline in histamine was significantly higher in the patients with rhinitis and asthma, compared with the rhinitis-only group.

CONCLUSION

Patients with AR and asthma have stronger nasal responsiveness to CDA compared with patients with rhinitis alone. This observation is consistent with the notion that compared with rhinitis alone, the presence of asthma and rhinitis signifies a higher degree of functional abnormality of the entire airway.

Activation of the kallikrein-kinin system and release of new kinins through alternative cleavage of kininogens by microbial and human cell proteinases

Kinins are released from kininogens through the activation of the Hageman factor-prekallikrein system or by tissue kallikrein. These peptides exert various biological activities, such as vascular permeability increase, smooth muscle contraction, pain sensation and induction of hypotension. In many instances kinins are thought to be involved in the pathophysiology of various diseases. Recent studies have revealed that microbial and human cell proteinases activate Hageman factor and/or prekallikrein, or directly release kinin from kininogens. This review discusses the activation of the kinin-release system by mast-cell tryptase and microbial proteinases, including gingipains, which are cysteine proteinases from Porphyromonas gingivalis , the major pathogen of periodontal disease. Each enzyme is evaluated in the context of its association to allergy and infectious diseases, respectively. Furthermore, a novel system of kinin generation directly from kininogens by the concerted action of two proteinases is described. An interesting example of this system with implications to bacterial pathogenicity is the release of kinins from kininogens by neutrophil elastase and a synergistic action of cysteine proteinases from Staphylococcus aureus . This alternative production of kinins by proteinases present in diseased sites indicates a significant contribution of proteinases other than kallikreins in kinin generation. Therefore kinin receptor antagonists and proteinase inhibitors may be useful as therapeutic agents.

Open-label evaluation of azelastine nasal spray in patients with seasonal allergic rhinitis and nonallergic vasomotor rhinitis

OBJECTIVE

The objective of the study was to evaluate the effectiveness of azelastine (Astelin) nasal spray, a topical second-generation antihistamine, in the treatment of symptoms of seasonal allergic rhinitis, seasonal allergic rhinitis with nonallergic triggers (mixed rhinitis), and nonallergic vasomotor rhinitis.

RESEARCH DESIGN AND METHODS

A total of 2343 primary care physicians, allergists, ENT specialists, and other health professionals participated in this 2-week, open-label evaluation of azelastine nasal spray. Data were collected through a physician questionnaire that included patient demographics, rhinitis diagnosis, medication history, and inclusion/exclusion criteria; and two patient questionnaires that included symptom history, response to previous rhinitis medications, symptom control, and level of satisfaction with azelastine nasal spray. A completed physician questionnaire and two completed patient questionnaires were required for each patient to be included in the analysis. Patients who qualified for enrollment were given open-label azelastine nasal spray and instructed to administer 2 sprays per nostril twice daily for 2 weeks.

RESULTS

A total of 1225 health professionals enrolled 7864 patients into the study. Completed physician and patient questionnaires were returned by 1081 health professionals and 5073 patients, 4364 of whom used azelastine nasal spray as their only rhinitis medication during the 2-week study period. The patients were predominantly caucasian (82.6%) and female (61.1%), with a mean age of 50 years. The majority had a diagnosis of mixed rhinitis (51.5%), followed by seasonal allergic rhinitis (32.3%), and nonallergic (vasomotor) rhinitis (16.2%). After 2 weeks of treatment, the percentage of patients reporting some control or complete control of individual symptoms ranged from 78% for postnasal drip in patients with nonallergic vasomotor rhinitis to 90% for sneezing in patients with seasonal allergic rhinitis. More than 85% of patients who reported difficulty sleeping or impairment of daytime activities due to rhinitis symptoms had improvement in these parameters. Azelastine nasal spray was well tolerated, the discontinuation rate due to adverse events was 2.3%.

CONCLUSIONS

Azelastine nasal spray was reported to control all rhinitis symptoms, including nasal congestion, regardless of rhinitis diagnosis during the 2-week study period. Patients with seasonal allergic rhinitis and patients with seasonal allergic rhinitis plus nonallergic triggers were identified as patient types most likely to respond to azelastine nasal spray.

Inflammatory mediators in nasal lavage among school-age children from urban and rural areas in São Paulo, Brazil

CONTEXT

Some studies have shown that inflammatory processes in the nasal air passages may reflect or affect those in the lower airways. We decided to indirectly assess the inflammatory status of the nasal airways in two groups of children with different sensitization rates to aeroallergens.

OBJECTIVE

To compare the inflammatory activity in the nasal airways, through the determination of mediators in nasal lavage fluid in two distinct populations.

TYPE OF STUDY

Cross-sectional study.

SETTING

Two public elementary schools, one in an urban setting and the other in a rural setting of the State of São Paulo, Brazil.

METHODS

Two groups of 40 elementary school children with different sensitization rates to aeroallergens were formed. Samples of nasal lavage fluid were assessed for eosinophil cationic protein (ECP) and tryptase. Non-parametric tests were used for statistical analysis.

RESULTS

Significantly higher levels of ECP were observed among students living in the urban area than those in the rural area (p < 0.05). No significant difference in the tryptase levels was observed. Also, the urban children who were sensitized to aeroallergens presented higher levels of ECP in nasal mucosa than the non-sensitized children, while this difference was not observed among the rural children.

DISCUSSION

The lack of mast cell activity and increased eosinophil degranulation revealed a chronic inflammatory state in the nasal air passages. The higher eosinophil activity in the urban area, coinciding with higher sensitization to aeroallergens, suggests that there must be some factors in the urban area that can modulate airway inflammation by influencing the activation of inflammatory cells.

CONCLUSION

Our findings showed that there was no difference in the concentrations of tryptase in nasal lavage fluids between the two studied groups. However, the children from the urban area presented with higher concentrations of eosinophil cationic protein than did those from the rural area. Also, the urban children who were sensitized to aeroallergens presented with greater concentrations of eosinophil cationic protein in nasal mucosa than the non-sensitized children, while this difference was not observed among the rural children.

Treatment of nonallergic perennial rhinitis

Nonallergic perennial rhinitis (also commonly referred to as vasomotor rhinitis) is a chronic non-IgE-mediated condition that is characterized by symptoms which are similar to those seen in allergic rhinitis, but which persist for over nine months each year. Although treatment of vasomotor rhinitis involves the use of either intranasal corticosteroids or antihistamines, the corticosteroids are generally not effective in treatment of all the symptoms of vasomotor rhinitis and have generally been shown to be effective in patients with eosinophilia. With the exception of azelastine, the only topical antihistamine to be approved by the FDA for the treatment of nonallergic rhinitis, the antihistamines have also produced inconsistent results. While clinical studies of azelastine have demonstrated that this drug is highly efficacious in the treatment of all the symptoms of vasomotor rhinitis, mechanistic studies have demonstrated that azelastine has potent anti-inflammatory effects (in particular attenuation of the expression and synthesis of pro-inflammatory cytokines, leukotrienes, and cell adhesion molecules), which are likely to contribute to its clinical efficacy. Furthermore, pharamacokinetic studies have suggested that since azelastine has a more rapid onset of action, compared to most other antihistamines and intranasal corticosteroids, then azelastine nasal spray may be considered as primary therapy for patients with symptoms of both allergic and/or vasomotor (nonallergic perennial) rhinitis.

A review of experimental studies on diesel exhaust particles and nasal epithelium alterations

The aim of the present review is to summarize biological events in nasal epithelium after short-term exposure to diesel exhaust particles (DEP). Therefore human, animal, and in vitro studies carried out since 1987 are reviewed. Short-term exposure results included qualitative alterations characterized by immediate nasal hyperresponsiveness, antioxidant responses, marked epithelial inflammation, and a specific humoral response. In addition, studies on combined DEP/allergen challenge reported that, besides their intrinsic deleterious properties, DEP produced adjuvant-like effects on the immediate and late-phase response to allergen challenge, since they are able to mimic effects occurring after allergen challenge. DEP act deeply in nasal epithelium by (1) directing cytokine gene expression toward a Th2 profile, (2) enhancing local antigen-specific immunoglobulin E (IgE) production, and (3) driving in vivo isotype switch to IgE. Furthermore, DEP can induce in allergic subjects sensitization to a neoallergen, sensitization that did not occur with exposure to the neoantigen alone. Particulate pollutants such as DEP, encountered in urban areas, are therefore thought to be contributing causal factors to the exaggerated sensitization to allergens in subjects with appropriate genetic predisposition, sensitization that they might not otherwise have experienced. These findings add weight to the hypothesis that DEP are involved in the increased prevalence of airway allergic diseases.

Modulation of tryptase secretion from human colon mast cells by histamine

AIM: To investigate the ability of histamine to modulate tryptase release from human colon mast cells and the potential mechanisms.

METHODS: Enzymatically dispersed cells from human colons were challenged with histamine, anti-IgE or calcium ionophore A23187 (CI), and the cell supernatants after challenge were collected. Tryptase release was determined with a sandwich ELISA procedure.

RESULTS: Histamine at concentrations from 1 ng/mL was able to induce a “bell” shape dose related release of tryptase from colon mast cells. The maximum release of tryptase was approximately 3.5 fold more than spontaneous release. As little as 10 ng/mL histamine showed a similar potency to 10 μg/mL anti-IgE in induction of tryptase release. Histamine induced release of tryptase initiated at 10 s when histamine (100 ng/mL) was added to cells, gradually increased thereafter, and completed at 5 min. Both pertussis toxin or metabolic inhibitors were able to inhibit histamine induced tryptase release. When histamine and anti-IgE were added to colon mast cells at the same time, the quantity of tryptase released was similar to that induced by anti-IgE alone. The similar results were observed with CI. However, when various concentrations of histamine were incubated with cells for 20 min before adding anti-IgE or CI, the quantity of tryptase released was similar to that was induced by histamine alone.

CONCLUSION: Histamine is a potent activator of human colon mast cells, which represents a novel and pivotal self-amplification mechanism of mast cell degranulation.

Modulation of tryptase secretion from human colon mast cells by histamine

AIM: To investigate the ability of histamine to modulate tryptase release from human colon mast cells and the potential mechanisms.

METHODS: Enzymatically dispersed cells from human colons were challenged with histamine, anti-IgE or calcium ionophore A23187 (CI), and the cell supernatants after challenge were collected. Tryptase release was determined with a sandwich ELISA procedure.

RESULTS: Histamine at concentrations from 1 ng/mL was able to induce a “bell” shape dose related release of tryptase from colon mast cells. The maximum release of tryptase was approximately 3.5 fold more than spontaneous release. As little as 10 ng/mL histamine showed a similar potency to 10 μg/mL anti-IgE in induction of tryptase release. Histamine induced release of tryptase initiated at 10 s when histamine (100 ng/mL) was added to cells, gradually increased thereafter, and completed at 5 min. Both pertussis toxin or metabolic inhibitors were able to inhibit histamine induced tryptase release. When histamine and anti-IgE were added to colon mast cells at the same time, the quantity of tryptase released was similar to that induced by anti-IgE alone. The similar results were observed with CI. However, when various concentrations of histamine were incubated with cells for 20 min before adding anti-IgE or CI, the quantity of tryptase released was similar to that was induced by histamine alone.

CONCLUSION: Histamine is a potent activator of human colon mast cells, which represents a novel and pivotal self-amplification mechanism of mast cell degranulation.

Analysis of transient and reversible effects of poly-L-arginine on the in vivo nasal absorption of FITC-dextran in rats

We have investigated whether poly-L-arginine, with a mean molecular weights of 8.9 and 45.5 kDa (poly-L-Arg (10) and poly-L-Arg (50)), can induce transient and reversible effects involving enhancement of the nasal absorption of fluorescein isothiocyanate-labeled dextran (MW 4.4 kDa, FD-4) and determined the main pathway for the increased transport of FD-4 in rats in vivo. Pre-administration and repeated administration studies were conducted involving the selection of different time intervals between intranasal administration of poly-L-Arg and administration of FD-4, with and without poly-L-Arg, to characterize these transient and reversible effects. The degradation of poly-L-Args in a diluted nasal drip was determined from the fluorescence of degraded poly-L-Arg-fluorescamine products. In the pre-administration study, poly-L-Arg exhibited a transient effect on the increased nasal FD-4 absorption depending on its molecular weight, associated with the degradation rate of poly-L-Arg in mucus. In the repeated administration study, additional poly-L-Arg produced similarly enhanced FD-4 absorption. Confocal laser scanning microscopy showed that fluorescence of FD-4 after co-administration of poly-L-Arg (50) was confined mainly to the paracellular spaces. In conclusion, poly-L-Arg exhibited molecular weight-dependent transient and reversible effects on the enhancement of nasal FD-4 absorption paracellularly in rats in vivo. The enzymatic degradation of poly-L-Arg is one of the key determinants of the transient effect on in vivo enhanced absorption of FD-4.

Update on nonallergic rhinitis

BACKGROUND

Although nonallergic rhinitis is a well recognized entity, its incidence and therapy have not been definitively studied. Recent epidemiologic studies and treatment trials have furthered our knowledge regarding the frequency of occurrence of this disorder and effective treatment modalities.

OBJECTIVE

To review and put into perspective recent advances in our knowledge regarding the incidence and significance as well as therapy of chronic nonallergic rhinitis. In addition, based upon these data, to propose a classification of this disorder.

DATA SOURCES

The MEDLINE database and the results of a national survey of allergists (National Rhinitis Task Force) conducted in 15 allergy practices involving 975 patients.

CONCLUSIONS

Nonallergic rhinitis is a common disease that probably affects as many as 17 million Americans. Of equal importance is that, based on available data, approximately 22 million people suffer with a combination of nonallergic rhinitis and allergic diseases (mixed rhinitis). Both nonallergic and mixed rhinitis occur more frequently in adults than in children, may be more common in female patients than in male patients, and are more likely to be perennial than seasonal. Agents demonstrating efficacy (based on controlled trials or having approval by the FDA) for the therapy of nonallergic rhinitis are azelastine and topical nasal steroids.

Allergic rhinitis: not purely a histamine-related disease

Allergic rhinitis is an inflammatory disorder of the nasal mucosa typified by the symptoms of nasal itch, sneeze, anterior nasal secretions, and nasal blockage. These symptoms arise from the interaction between mediators and neural, vascular, and glandular structures within the nose. Nasal itch, sneezes, and rhinorrhoea are predominantly neural in origin, while nasal obstruction is predominantly vascular. Nasal biopsy studies show accumulation of eosinophils within the lamina propria and epithelium and an increase in tissue and cell surface basophils in both seasonal and perennial allergic rhinitis. These cells are in an activated state. Within the epithelium, increased numbers of mast cells, T cells and Langerhans' cells, which induce T-cell activation, are found. The accumulation of these cells can be linked to chemokine and cytokine generation by the epithelial cells themselves. Thus, the tissue cell recruitment is orchestrated by activated mast cells, T cells, and epithelial cells, with the recruited tissue eosinophils also contributing to their persistence at this site through autocrine mechanisms. Mast cells generate an array of mediators including histamine, tryptase, leukotrienes, and prostaglandins. Histamine is also generated by basophils. Eosinophils and basophils contribute to the leukotriene synthesis within the tissue. Histamine nasal insufflation induces nasal itch, sneeze, and rhinorrhoea as well as nasal blockage, thereby reproducing all the symptoms of allergic rhinitis. These effects are primarily mediated by H1-receptors, and H1-receptor antagonists are a prominent treatment. Antagonism of histamine at these receptors reduces symptoms by about 40-50%, with the greatest effect on the neurally mediated responses. Thus, histamine is a major mediator of allergic rhinitis, but not the sole contributor. Nasal insufflation with leukotrienes, prostaglandins, or kinins is associated with the development of nasal blockage. These mediators act primarily on the nasal vasculature and, in this respect, leukotrienes are potent mediators. Leukotrienes also induce plasma protein exudation, which contributes to the anterior nasal secretions. Studies with combination products have suggested that modifying the effects of both leukotrienes and histamine has complementary effects in relieving nasal symptoms, indicating that both these mediators are relevant to disease expression.

Efficacy of azelastine nasal spray in the treatment of vasomotor (perennial nonallergic) rhinitis

BACKGROUND

Azelastine hydrochloride is an antihistamine with anti-inflammatory properties that is available in the United States in a nasal spray formulation for the treatment of seasonal allergic rhinitis. Vasomotor (perennial nonallergic) rhinitis (VMR) is a noninfectious, chronic rhinitis usually not associated with inflammatory cell infiltration.

OBJECTIVE

Two multicenter, randomized, double-blind, placebo-controlled, parallel-group clinical trials were conducted to determine whether patients with symptoms of VMR (rhinorrhea, sneezing, postnasal drip, and nasal congestion) could be effectively treated with azelastine nasal spray.

METHODS

All of the patients who participated in the trials had a diagnosis of VMR, symptoms for at least 1 year, negative skin tests for a mixed panel of seasonal and perennial allergens, and a nasal cytology examination negative for eosinophils. After a 1-week, single-blind, placebo lead-in period, patients who met the symptom severity qualification criteria were randomized to receive either azelastine nasal spray (two sprays per nostril twice daily, 1.1 mg/day) or placebo nasal spray for 21 days. Patients recorded the severity of their VMR symptoms on diary cards each morning and evening of the trial using a four-point symptom rating scale (0 = none to 3 = severe). The primary efficacy variable was the overall reduction from baseline in the total vasomotor rhinitis symptom score (TVRSS) over the 21-day, double-blind treatment period.

RESULTS

In both studies, azelastine nasal spray significantly (study 1, P = .002; study 2, P = .005) reduced the TVRSS from baseline when compared with placebo. Significant improvement was observed within the first week and improvement in all symptoms favored treatment with azelastine nasal spray. No serious or unexpected adverse events were reported in either study. Bitter taste (19% vs 2%) was the only adverse experience that occurred with a statistically significantly greater incidence in the azelastine group than in the placebo group.

CONCLUSIONS

This is the first demonstration of the efficacy of an antihistamine in the therapy of VMR in two double-blind, placebo-controlled clinical trials.

Diesel exhaust particles directly induce activated mast cells to degranulate and increase histamine levels and symptom severity

BACKGROUND

The ability of combustion products, such as diesel exhaust particles (DEPs), to modulate the immune system has now been firmly established. DEPs can synergize with allergen at the human upper respiratory mucosa to enhance allergen-specific IgE production, initiate a T(H)2 cytokine environment, and even promote primary allergic sensitization. Experiments suggest that these effects result from the initial activation of mast cells to produce IL-4.

OBJECTIVE

We sought to demonstrate that in vivo mast cell activation by DEPs plus allergen will also affect the release of classic mast cell mediators and consequently enhance the immediate-phase response.

METHODS

Dust mite-sensitive subjects were challenged intranasally with allergen, and symptom scores and histamine levels in nasal wash samples were compared after prechallenge with 0.3 mg of DEPs.

RESULTS

If the subjects were first sprayed with DEPs, mean symptom scores rose from 3.7 to 9.9; additionally, only one fifth of the amount of intranasal dust mite allergen was required to induce clinical symptoms. DEPs alone had no effect. The changes in symptoms correlated with histamine levels measured in nasal lavage specimens from these subjects. Although challenge with DEPs alone did not induce histamine release, challenge with both DEPs and allergen resulted in 3-fold higher histamine concentrations than those seen with allergen alone. In contrast, carbon black particles (elemental carbon devoid of chemicals) had no effect. The role of chemicals was confirmed because degranulation of a murine mast cell line by FcepsilonRI cross-linking was increased significantly (by 72%) by the soluble organic chemicals extracted from DEPs.

CONCLUSIONS

Overall, these results suggest that exposure to DEPs can enhance the severity of clinical symptoms to allergen by enhancing mast cell degranulation.

Nasal hyperosmolar challenge with a dry powder of mannitol in patients with allergic rhinitis. Evidence for epithelial cell involvement

BACKGROUND

The responses to airway hyperosmolar challenges probably involve various inflammatory mediators. However, it is not fully understood which cell type/types are the source of these mediators. Potential cell types include mast cell, epithelial cell and the sensory c-fibre nerve cell.

OBJECTIVE

To clarify which cell types are involved with the mediator response to hyperosmolarity in the human airway.

METHODS

Ten healthy subjects, 11 patients with nonactive allergic rhinitis, and nine with active allergic rhinitis were challenged intranasally with mannitol powder, and with sham provocation, on separate days. Symptoms were assessed by visual analogue scales and nasal patency by measuring the nasal peak inspiratory flow (nPIF). Nasal lavage fluid levels of alpha(2)-macroglobulin (an index of plasma extravasation), substance P (an index of sensory nerve cell activation), tryptase (an index of mast cell activation) and 15-hydroxyeicosatetraenoic acid (15-HETE, an index of epithelial cell activation) were analysed.

RESULTS

Immediate, although transient burning was the most prominent symptom in all groups whereas only the patients with active rhinitis experienced a fall in nPIF. Mannitol significantly increased the nasal lavage fluid 15-HETE levels in the allergic patients (P < 0.01 vs the sham challenge), but not in the healthy subjects. The increase in 15-HETE correlated with nasal symptoms for itching (r(s) = 0.65, P = 0.019) and burning (r(s) = 0.72, P = 0.009). Detectable levels of tryptase was found only in five allergic subjects. Lavage levels of substance P and alpha(2)-macroglobulin did not not change.

CONCLUSION

Epithelial cell seems to be involved with the mediator response to airway hyperosmolar challenge. The roles of sensory c-fibre nerve cell and mast cell remained less clear.

Mast cell tryptase in dermal neurogenic inflammation

BACKGROUND

Mast cell activation has been assumed to play a role in dermal neurogenic inflammation: C fibre-derived neuropeptides activating mast cells and releasing histamine, which in turn would activate C fibres.

OBJECTIVE

To test this hypothesis mast cell tryptase (MCT) was measured inside the axon reflex flare area. Axon reflexes were elicited by histamine or compound 48/80, a polyanionic mast cell-degranulating substance. The time course of plasma extravasation and release of histamine and MCT from dermal mast cells in neurogenic inflammation was measured in vivo by intradermal microdialysis in humans.

METHODS

Single hollow plasmapheresis fibres (pore cutoff size: 3000 kDa) were inserted intracutaneously at the volar forearm and perfused with Ringer's solution (4 microL/min) with one microdialysis fibre located at the planned stimulation site and a second inside the axon reflex area. Neurogenic inflammation was induced by intraprobe delivery of either histamine or the mast cell-degranulating agent compound 48/80. Mediator release was measured at the stimulation sites and inside the arising axon reflex flare area.

RESULTS

Mast cell degranulation induced marked plasma protein extravasation (PPE 0.25 +/- 0.04-1.31 +/- 0.6 mg/mL; pre- and post-stimulation, mean +/- sem, n = 7) and release of histamine (2.0 +/- 0.9-38.7 +/- 1.4 ng/mL) and MCT (9.84 +/- 2.4-92.2 +/- 21.6 ng/mL). Interestingly, in addition to increasing PPE (0.33 +/- 0. 11-1.85 +/- 0.9 mg/mL), histamine also induced a slight but significant increase in MCT (11.3 +/- 3.0-12.4 +/- 2.3 ng/mL). No evidence for mast cell activation was observed inside the axon reflex areas, where PPE (0.34 +/- 0.03-0.25 +/- 0.02 mg/mL), histamine (1.64 +/- 0.5-1.46 +/- 0.4 ng/mL) and MCT concentration (11.6 +/- 3.1-7.6 +/- 1.7 ng/mL) gradually decreased.

CONCLUSION

It is concluded that dermal neurogenic inflammation does not degranulate mast cells.

Histamine release upon adenosine 5'-monophosphate (AMP) nasal provocation in allergic subjects

BACKGROUND

Nasal provocation with adenosine 5'-monophosphate (AMP) elicits nasal symptoms in subjects with rhinitis. Histamine released from mast cells may play a part in AMP induced nasal responses.

METHODS

Symptoms of rhinitis were recorded and histamine release in the fluid obtained by nasal lavage after AMP, guanosine 5'-monophosphate (GMP), and placebo instillations was measured in nine subjects with allergic rhinitis and nine non-allergic controls in a double blind, randomised, placebo controlled study.

RESULTS

No symptoms or significant increases in histamine were observed after GMP and placebo challenge. Significantly higher levels of histamine were seen in the nasal lavage fluids of allergic subjects following AMP challenge than in nonallergic controls, the median (range) histamine concentration increasing from the baseline value of 1.62 (0.44-6.99) ng/ml to 6.45 (0.81-16.17) ng/ml at three minutes. No increase in histamine levels was seen in the non-allergic subjects in whom the median histamine concentration was 1.13 (0.29-4.25) ng/ml at baseline and 0.97 (0.31-5.89) ng/ml three minutes after AMP challenge.

CONCLUSIONS

AMP elicits an immediate rise in histamine levels in the nasal lavage fluid of allergic subjects compared with non-allergic individuals. These findings indicate that the exaggerated nasal response to adenosine may reflect mast cell priming in vivo, thus supporting its application as a potential new marker of allergic inflammation.

The kinin system in rhinitis and asthma

The past decade has seen renewed interest in the potential role of kinins in airway diseases. The correlation between kinin generation and symptoms of inflammation, together with the demonstration that administration of kinins to the airway mucosa can induce relevant symptoms, provides strong circumstantial support for a role of kinins in the pathogenesis of airway diseases, such as allergic and viral rhinitis and asthma. Definitive studies of the effects of blockade of kinin actions on symptomatic responses, however, are still needed. The effects of kinins in the airways, and the mechanisms by which they exert their actions clearly vary depending on the presence of inflammation in the airways. Although a growing body of evidence implicates activation of sensory nerves as an important component of kinin effects in inflamed airways, the components of inflammation that modify the response of these sensory nerves, the mechanisms by which neuronal responsiveness alters, and the degree of selectivity of neuronal activation to bradykinin are all topics that require further delineation.

A novel mechanism for bradykinin production at inflammatory sites. Diverse effects of a mixture of neutrophil elastase and mast cell tryptase versus tissue and plasma kallikreins on native and oxidized kininogens

Coprocessing of kininogens by a mixture of human mast cell tryptase and neutrophil elastase was explored as a potential substitute for the kallikrein-dependent pathway for kinin generation during inflammation. Tryptase easily excised bradykinin from the synthetic heptadecapeptide, ISLMKRPPGFSPFRSSR, but was unable to produce significant amounts of kinin by proteolysis of kininogens. However, a mixture of tryptase and elastase released bradykinin from each protein with a yield comparable to that of human plasma kallikrein. Significantly, neither plasma nor tissue kallikrein was able to effectively process N-chlorosuccinimide-oxidized high molecular weight kininogen, an effect attributed to the oxidation of a methionine residue upstream from the N terminus of the kinin domain. In support of these results the model heptadecapetide, ISL(MO)KRPPGFSPFRSSR, was also resistant to hydrolysis by either kallikrein. In contrast, the release of bradykinin from oxidized peptide or protein substrates by the tryptase/elastase mixture was not altered. Because kininogen modification may occur at inflammatory sites, as a result of the oxidative burst of recruited neutrophils and macrophages, these results suggest an alternative pathway for kinin production and the necessity for the novel utilization of two specific proteinases known to be released from these cells during inflammatory episodes.

Intranasal salmeterol inhibits allergen-induced vascular permeability but not mast cell activation or cellular infiltration

BACKGROUND

Salmeterol is a long-acting beta2-adrenergic agonist that is widely used in the treatment of asthma. It has been suggested that non-bronchodilator actions of salmeterol may contribute to its efficacy.

OBJECTIVE

To further evaluate the potential non-bronchodilator actions of salmeterol in vivo, using a model of nasal challenge with allergen.

METHODS

Twelve asymptomatic subjects with seasonal allergic rhinitis participated in a randomized, double-blind, placebo-controlled crossover trial of the effects of a single dose of 100 microg of salmeterol on the response to allergen challenge. Sneezing and symptom scores, and levels of histamine and albumin in nasal lavages, were measured throughout the protocol. Concentrations of tryptase, prostaglandin D2 and lysozyme were measured during the acute allergic response, while levels of IL-3, IL-5 and IL-8 were measured at later time points. Numbers of eosinophils and of total white blood cells were also recorded.

RESULTS

Salmeterol did not affect sneezing or symptom scores at any point. During the immediate response to allergen challenge, mast cell activation, reflected by concentrations of histamine, tryptase and prostaglandin D2, and serous glandular secretion, assessed by measurements of lysozyme, were unaffected by salmeterol treatment but vascular permeability, reflected by concentrations of albumin in nasal lavages, was significantly reduced. At later time points, salmeterol had no effect on levels of histamine or albumin and did not affect cellular infiltration. Concentrations of IL-3, IL-5 and IL-8 were not increased by allergen challenge in these subjects, so the effects of salmeterol could not be evaluated.

CONCLUSIONS

Treatment with a single dose of salmeterol had no effect on activation of mast cells or cellular infiltration but inhibited vascular permeability. The ability of salmeterol to inhibit antigen-induced vascular permeability may contribute to its therapeutic efficacy in asthma.

Subjective and objective assessments in patients with seasonal allergic rhinitis: effects of therapy with mometasone furoate nasal spray

BACKGROUND

Efficacy of topical nasal steroid therapy for allergic rhinitis is usually evaluated by patient and clinician assessments of subjective symptom changes in diaries and at clinical interviews.

OBJECTIVE

We sought to complement the subjective measures with objective measures of nasal cytology, biochemistry, and function.

METHODS

In this double-blind, randomized study patients with seasonal allergic rhinitis (SAR) 12 years of age or older received 200 microg mometasone furoate nasal spray (n = 80) or placebo spray (n = 41) once daily for 2 weeks. Subjective assessments by clinician and patient comprised symptom/sign scores and overall therapeutic response evaluations. Objective measures included nasal cytology, nasal biochemistry, nasal airway resistance (NAR), mucociliary clearance, and olfactory functions.

RESULTS

Mometasone furoate produced a significantly greater decrease than placebo in subjective measures of SAR for total symptom score (-46% vs -30%, p < 0.05), total nasal score (-47% vs -30%, p < 0.024), individual nasal symptom scores, and overall therapeutic response. The objective measures of eosinophil, basophil, and neutrophil counts and mucociliary clearance were significantly better in mometasone furoate- than in placebo-treated patients. Similarly, within-treatment statistically significant improvements were produced by mometasone furoate but not by placebo sprays for levels of eosinophilic cationic protein, tryptase and albumin, NAR, and odor identification. Significant positive correlations were found between NAR and nasal stuffiness and between eosinophils, basophils, and neutrophils and both eosinophilic cationic protein and albumin.

CONCLUSION

Subjective measures of SAR were significantly improved in the mometasone furoate group by comparison with placebo-treated patients. Objective assessments supported the subjective findings because within-treatment measures were frequently significantly improved after mometasone furoate treatment but not after placebo treatment.