The kinetics of allergen-induced eotaxin level in nasal lavage fluid: its key role in eosinophil recruitment in nasal mucosa

Eotaxin (CCL11) is a potent eosinophil chemoattractant belonging to the C-C chemokine. To evaluate the role of eotaxin in eosinophilic inflammation in nasal mucosa, we investigated the levels of eosinophil chemoattractants in nasal lavage fluids obtained after antigen challenge, compared with eosinophil counts and eosinophil protein X (EPX) levels. In subjects with allergic rhinitis, allergen challenge led to parallel increases in eosinophil counts, levels of EPX, and eotaxin concentrations in nasal lavage fluid. The levels of eotaxin in lavage samples showed strong correlation with lavage levels of eosinophil counts and EPX. Normal subjects had few, if any, eosinophils and EPX as well as the measured parameters in their nasal lavage fluids before and after antigen challenge. In our experiments of eosinophil endothelial transmigration (TEM) assay using the nasal microvascular endothelial cells, eotaxin showed the most potent effect among various eosinophil chemoattractants. In addition, treatment of eosinophils with anti-CCR-3 mAb significantly blocked eosinophil TEM induced by homogenate of nasal mucosa. These results indicate that eotaxin has an important role in eosinophil-dependent inflammation in nasal mucosa and suggest that blocking eotaxin or CCR-3 might be useful for new therapeutic tools of allergic rhinitis.

Prevention of allergic inflammation by a novel prostaglandin receptor antagonist, S-5751

Prostaglandin (PG) D2, the major cyclooxygenase metabolite generated from immunologically stimulated mast cells, is thought to contribute to the pathogenesis of allergic diseases due to its various inflammatory effects. However, since no DP receptor antagonist has been developed as an antiallergic drug, the role of PGD2 in the pathogenesis of allergic diseases remains uncertain. Here, we report the in vivo efficacy of our newly established DP receptor antagonist, S-5751 [((Z)-7-[(1R,2R,3S,5S)-2-(5-hydroxy benzo[b]thiophen-3-ylcarbonylamino)-10-norpinan-3-yl]hept-5- enoic acid)], using various allergic inflammation guinea pig models. In allergic rhinitis models, oral administration of S-5751 dramatically inhibited not only early nasal responses, as assessed by sneezing, mucosal plasma exudation, and nasal blockage, but also late responses such as mucosal plasma exudation and eosinophil infiltration. Even when S-5751 was administered after recovery from the early responses, these late phase responses were almost completely suppressed. In addition, S-5751 alleviated allergen-induced plasma exudation in the conjunctiva in an allergic conjunctivitis model and antigen-induced eosinophil infiltration into the lung in an asthma model. These findings provide evidence for the crucial role of PGD2 as a mediator of allergic inflammation in guinea pigs and suggest that DP receptor antagonists may be useful in the treatment of allergic diseases triggered by mast cell activation.

Measurement of inflammatory mediators of mast cells and eosinophils in native nasal lavage fluid in nasal polyposis

BACKGROUND

Nasal polyposis (NP) often coexists with asthma, rhinitis and sinusitis. Polyp histology typically shows chronic, eosinophilic inflammation. The inflammatory cell infiltrate generally includes eosinophils, lymphocytes, plasma cells and mast cells.

OBJECTIVE

To gain insight into the natural history of NP, we analysed mediator levels and leukocyte values in nasal fluids and eosinophil cationic protein (ECP), total IgE levels and eosinophils in the blood in several groups of both allergic and non-allergic patients with nasal polyps and in patients with allergic rhinitis (AR).

METHODS

Thirty-two patients with nasal polyps entered the study. As a control group, we studied 55 patients with AR, i.e. 20 patients with seasonal AR to grass pollen, 24 with AR sensitive to Parietaria and 11 with AR sensitive to house dust mite (HDM). Eighteen patients with nasal polyps were also allergic patients (8 were sensitive to Parietaria and 10 were sensitive to HDM), whereas 14 were non-allergic patients. Tryptase and histamine values were assayed in nasal fluids, whereas total IgE was determined in serum. ECP values were assayed both in nasal fluids and serum. Eosinophils were quantified both in the blood and nasal fluids.

RESULTS

Tryptase levels were significantly higher in the nasal lavages from patients with NP than in those from patients without NP (4.7 vs. 3.5 U/l, p < 0.001) and correlated with symptom scores (r(s) = 0.42, p < 0.0001). The median levels of histamine in nasal fluids from patients with NP were also significantly higher than those observed in patients without NP (50.0 vs. 21.3 ng/ml, p < 0.001), but did not correlate with symptom scores. Finally, the median levels of ECP in nasal fluids from patients with NP were significantly higher than those observed in patients without NP (38.1 vs. 16.1 ng/ml, p < 0.001) and correlated with symptom scores (r(s) = 0.38, p < 0.001). Analysis of variance showed that, among the variables studied, the presence of nasal polyps was the factor responsible for the higher levels of tryptase, histamine and ECP in nasal fluids. With regard to leukocyte counts in nasal fluids, no significant differences were observed between rhinitis patients with NP and those without NP. With regard to serum ECP and serum total IgE, no significant differences were detected between the two groups under study. Blood eosinophil levels in patients with NP were significantly higher than those observed in patients without NP (5.8 vs. 5.6, p = 0.002). Analysis of variance showed that both the presence of nasal polyps and the type of sensitisation were important. Considering the total symptom scores, no significant differences were observed between rhinitis patients with NP and those without NP.

CONCLUSIONS

The present findings are consistent with the view that chronic eosinophil mucosal inflammatory disease in NP involves a self-sustaining mechanism, i.e. local release of inflammatory mediators, independent of allergen stimulation of nasal mucosa. Increased release of inflammatory mediators contributes to the development of nasal polyps, determining oedema and an increased recruitment of inflammatory cells. Besides eosinophils, mast cells also play a key role in this process.

Perforin hyperreleasability and depletion in cytotoxic T cells from patients with exacerbated atopic dermatitis and asymptomatic rhinoconjunctivitis allergica

BACKGROUND

As a plasma membrane pore-forming protein, perforin is essential for T-cell cytotoxicity mediated by lytic granules. Recent studies on the immune system of perforin knockout mice demonstrated striking similarities to the immunopathology of atopic diseases.

OBJECTIVE

We sought to investigate the perforin system of atopic patients.

METHODS

Monoclonal antibodies were used to characterize perforin-positive PBMCs of patients with exacerbated atopic dermatitis (AD) and asymptomatic rhinoconjunctivitis allergica (RCA) by means of immunoflow cytometry. In addition, a perforin release assay was developed to quantify the velocity of ionomycin and phorbol 12-myristate 13-acetate-induced secretion of lytic granules.

RESULTS

In atopic patients significantly fewer lymphocytes contained perforin-positive lytic granules compared with those of healthy control subjects (patients with AD: 14% +/- 5%, n = 13, P <.0001; patients with RCA: 24% +/- 5%, n = 9, P <.01; healthy control subjects: 33% +/- 11%, n = 13). Of all CD8(hi+) cytotoxic T lymphocytes (CTLs), only 18% +/- 9% and 17% +/- 12% were perforin-positive in patients with AD and RCA, respectively, compared with 44% +/- 13% in control subjects (P <.0001). In addition, perforin-positive CD8(hi+) CTLs of atopic patients released their perforin twice as fast and more completely than control CTLs. This means that 50% of initially perforin-positive CD8(hi+) CTLs from patients with AD and RCA released their perforin completely within 32 +/- 16 and 36 +/- 19 minutes, respectively, and an over 85% release was reached within 113 +/- 41 and 118 +/- 60 minutes, respectively. In CTLs of healthy control subjects, however, it took 64 +/- 40 minutes to achieve a 50% release of lytic granules, and an 85% depletion was not reached in 60% of healthy control subjects, even after 180 minutes.

CONCLUSION

The perforin hyperreleasability explains, at least in part, the decreased percentage of perforin-positive CD8(hi+) CTLs in atopic patients. These distortions in the system of lytic granules of atopic patients may contribute to the functional defects observed in T-cell cytotoxicity in vivo and in vitro in patients with AD and RCA.

Receiver operating characteristics curve analysis of cutaneous skin test reactions to predict hay fever and asthma symptoms in the Normative Aging Study

BACKGROUND

We used receiver operating characteristic (ROC) curves to determine optimal cutoff values and to evaluate the ability of ragweed, mixed grasses, mixed trees, and house-dust antigens to predict symptoms of hay fever and asthma.

METHODS

Between 1984 and 1993, 1386 members of the Normative Aging Study cohort had at least one examination that included evaluation of cutaneous hypersensitivity to common aeroallergens by skin prick testing. Standard questionnaires based on the American Thoracic Society DLD-78 questionnaire obtained information on respiratory symptoms, illness, and smoking habits.

RESULTS

Ragweed was the best univariate predictor for both hay fever and asthma symptoms: the area under the ROC curve for hay fever was 0.71 (95%) CI 0.67-0.74); for asthma, it was 0.65 (95% CI 0.55-0.75). For hay fever, dichotomizing the average reaction to four antigens at 2 mm gave a sensitivity of 56% and a specificity of 83%; at 3 mm, the sensitivity was 38% and specificity 92%. For asthma, dichotomizing the skin test reaction at 2 mm gave a sensitivity ranging from 30% for reaction to mixed grasses to 56% for the ragweed antigen reaction.

CONCLUSIONS

Although in this older population skin test reactivities did not predict current asthma symptoms with high sensitivity, our results support the use of cutoff values of 2 or 3 mm as commonly used in studies of hay fever symptoms.

Current controversies: sinus disease and the lower airways

This review explores the literature dealing with the relation between the upper and lower airways, including the possible link between chronic sinus disease and asthma, and between chronic sinus disease and cough. Imaging studies, microbiology, epidemiology, animal studies, and effects of treatment are discussed. Available studies do not prove that upper airway disease directly causes lower airway pathology. Allergic rhinitis causing nasal blockage needs treatment, as does symptomatic sinus disease. Where there is concurrent disease of the upper and lower airways, both conditions need to be treated adequately. Further research is required to establish the relation between upper and lower airways, and animal models may help to unravel the mechanisms and impact of treatment. Randomized, blinded, controlled trials are needed in both children and adults to assess therapies of chronic sinusitis and the response of asthma.

Absence of nasal mucosal atrophy with fluticasone aqueous nasal spray

OBJECTIVE

To evaluate whether 1 year of continuous treatment with intranasal fluticasone propionate would lead to atrophy in the nasal mucosa compared with an active control, oral terfenadine.

DESIGN

Prospective, randomized, multicenter, open-label, parallel-group study.

SETTING

Two tertiary care academic institutions.

PATIENTS

Seventy-five subjects older than 18 years with perennial allergic rhinitis.

INTERVENTIONS

Patients received either fluticasone propionate aqueous nasal spray, 200 microg once daily, or terfenadine, 60 mg twice daily, for 1 year. Nasal biopsy specimens were obtained before and after 1 year of treatment and were evaluated for evidence of atrophy.

MAIN OUTCOME MEASURES

Epithelial and collagen layer thickness of the nasal mucosa as assessed by light microscopy and the presence and degree of edema, and regularity of collagen fibrils as assessed by electron microscopy. Analyses were performed without knowledge of subject identity or treatment assignment.

RESULTS

Neither fluticasone nor terfenadine treatment led to atrophy in the nasal mucosa by clinical or histologic observation. No significant changes from baseline were observed for any assessment of atrophy. In contrast to what would have been expected if atrophy were to occur, mean epithelial layer thickness in the fluticasone group significantly increased compared with terfenadine treatment (P = .03).

CONCLUSIONS

Treatment with intranasal fluticasone for 1 year increases the thickness of the nasal epithelium as compared with a year's treatment with terfenadine and does not lead to atrophy in the nasal mucosa. The increased thickness in the fluticasone treatment may represent repair from epithelial damage caused by chronic allergic inflammation.

Paediatric issues relating to the pharmacotherapy of allergic rhinitis

The prevalence of allergic rhinitis in children has risen significantly over the last two decades. Important comorbidities like asthma have grown in parallel due to a complex mix of environmental and genetic factors. These conditions have similar allergic inflammatory mechanisms, which raises the possibility of treating both conditions by targeting shared inflammatory mediators pharmacologically. The first line treatment for paediatric allergic rhinitis is a topical nasal corticosteroid or a non-sedating antihistamine. Available intranasal corticosteroids show superior symptom control to second-generation antihistamines. However, most topical steroids and non-sedating antihistamines have equivalent clinical efficacy within their respective classes, so the choice of agent depends on safety and tolerability. Ideally, topical nasal steroids should exhibit high local receptor binding affinity and low systemic bioavailability, allied with a lack of long-term growth suppression in children and adolescents. Regular use of topical steroids is advisable, but intermittent and prophylactic use is also effective. Second-generation antihistamines are effective and some have no adverse cardiac or sedative effects. Non-sedating antihistamine treatment can ameliorate rhinitis-induced decrements in learning. alpha-Adrenergic nasal decongestants provide short-term benefit, but topical agents can cause rebound symptoms. Prophylactic treatment with chromones is safe and effective, but multiple daily dosing is needed. Ipratroprium bromide nasal spray is useful as an intermittent therapy for mild disease or as add-on treatment, but its effect is limited to the control of rhinorrhoea. Children with allergic rhinitis should receive pharmacotherapy if allergen avoidance measures are ineffective, ideally with a topical intranasal steroid or a second-generation antihistamine.

Cytokine expression in the lower airways of nonasthmatic subjects with allergic rhinitis: influence of natural allergen exposure

BACKGROUND

Natural exposure to pollen provokes an increase in airway responsiveness in nonasthmatic subjects with seasonal allergic rhinitis. This natural exposure may induce inflammatory cell recruitment and cytokine release, leading to lower airway inflammation.

OBJECTIVE

The aim of this study was to characterize lower airway inflammation in nonasthmatic pollen-sensitive subjects.

METHODS

We performed immunohistochemical tests on bronchial biopsy specimens from subjects with rhinitis who had no past or current history of asthma to evaluate cytokine expression and inflammatory cell numbers and activation both in and out of the pollen season.

RESULTS

The number of CD4(+), CD8(+), and CD45RO(+) lymphocyte subpopulations were significantly higher during the pollen season compared with the out-of-season period (P <.04). Furthermore, EG1(+) cells tended to increase after natural pollen exposure (P =.06). The number of IL-5(+) cells increased significantly after natural exposure to pollen compared with out-of-season numbers (P <.01). This increase in IL-5 expression was correlated with the numbers of CD3(+), CD4(+), CD45RO(+), and EG1(+) cells. The numbers of tryptase-positive, IFN-gamma(+), and IL-4(+) cells did not change after natural exposure.

CONCLUSION

This study showed that natural pollen exposure was associated with an increase in lymphocyte numbers, eosinophil recruitment, and IL-5 expression in the bronchial mucosa of nonasthmatic subjects with allergic rhinitis.

Basophil and eosinophil accumulation and mast cell degranulation in the nasal mucosa of patients with hay fever after local allergen provocation

BACKGROUND

Basophils and mast cells have certain similarities and are believed to be important in upper and lower respiratory allergy.

OBJECTIVE

We sought to apply immunohistology to investigate the distribution and numbers of mast cells and basophils in the nasal mucosa after allergen provocation.

METHODS

Allergen challenge with grass pollen was performed in 9 patients with seasonal allergic rhinitis out of the hay fever season. Nasal biopsy specimens were taken before and approximately 1 hour, 24 hours, and 1 week after intranasal allergen provocation. We determined relative numbers and their phenotypic characteristics by using mAbs specific for tryptase, chymase, IgE, eosinophils (BMK-13), and a new mAb against basophils (BB1) by using immunohistochemistry in frozen sections.

RESULTS

In the nasal mucosa at baseline, practically no basophils were found in the epithelium. A significant increase in numbers was found in the epithelium and lamina propria of the nasal mucosa in the early phase as early as 1 hour after allergen provocation. At 24 hours and 1 week after allergen provocation, a significant increase in basophil numbers was found in the lamina propria only. The proportion of mast cells staining for chymase in the lamina propria decreased from a median of 38% (range, 0%-82%) to 14% (range, 0%-78%) within 1 hour of allergen provocation. The proportion of mast cells staining for chymase increased from 1% (range, 0%-86%) at baseline to 21% (range, 3%-85%) within 1 hour of allergen provocation. One week after provocation, mast cells returned to baseline numbers. A definite tissue eosinophilia was observed after allergen provocation.

CONCLUSION

Basophil numbers are increased in the epithelium and lamina propria of the nasal mucosa of subjects with rhinitis after allergen challenge, with influx already apparent at 1 hour. Moreover, changes in mast cell percentages and numbers were observed within 1 hour of allergen provocation.

Piecemeal degranulation of peripheral blood eosinophils: a study of allergic subjects during and out of the pollen season

The variability of serum and plasma levels of eosinophil granule proteins in different clinical conditions, interpreted as the result of different patterns of cytokine priming, suggests a selective mobilization of granule proteins. Inasmuch as piecemeal degranulation (PM) is the mechanism proposed for the differential release of eosinophil granule proteins, we decided to investigate whether blood eosinophils from allergic subjects show characteristics of PM during natural allergen challenge. Eosinophils from three birch-sensitive subjects were studied before and during the pollen season. Electron microscopy analysis showed that during the season, eosinophils presented morphologic features of PM. By immunogold labeling, eosinophil cationic protein (ECP) was detected not only in normal specific granules but also in the cytoplasm, in the vicinity of partially lucent specific granules. These results were confirmed by subcellular fractionation, where the amount of ECP associated with compartments containing small vesicles increased 2-fold during the pollen season. A study of the distribution of ECP, eosinophil peroxidase, and hexosaminidase in eosinophils of different densities showed that the profile of each of these proteins differed depending on cell density. All of these proteins decreased in the specific granule of hypodense cells and increased in other cell compartments. We conclude that allergen exposure causes PM of the peripheral blood eosinophils of allergic subjects, and that the density of these cells reflects the degree of degranulation. Our results provide novel information for the understanding of the selective mobilization of granule proteins into the circulation.

Involvement of eosinophils in the early-phase allergic reaction in a guinea pig rhinitis model

BACKGROUND

Eosinophils are found in the nasal lavage fluid (NLF) and nasal biopsies of patients with allergic rhinitis after a nasal antigen challenge, and associated not only with a late-phase allergic reaction (LPR) but also an early phase allergic reaction (EPR). Numerous studies have been carried out to clarify the participation of eosinophils in LPR or airway hyperresponsiveness. However, there has been no published report describing in detail the role of eosinophils during EPR. To better understand the involvement of eosinophils in EPR, we studied the effects of repeated antigen challenges on nasal airway responsiveness and eosinophilic inflammation in EPR using a guinea pig rhinitis model.

METHODS

Nasal airway responsiveness was measured as the nasal airway resistance (NAR) after nasal antigen provocation. Eosinophilic inflammation during EPR was assessed by nasal lavage and histopathological examination using two groups of animals: those in group 1 were subjected to a sensitization pretreatment only, and those in group 2 were subjected to a pretreatment of sensitization followed by repeated nasal challenges.

RESULTS

Repeated antigen challenges induced nasal hyperresponsiveness as indicated by a decrease in the antigen provocation dose and a significant increase in NAR. Furthermore, significant increases in eosinophil counts, eosinophil peroxidase (EPO) activity and protein content in NLF during EPR were observed following antigen provocation in group 2. There were significant correlations between the levels of these parameters, and albumin was the most prevalent of the proteins in NLF. Histopathological examination showed that the degree of eosinophil infiltration into the lamina propria of the nasal mucosa of the animals in group 2 was significantly and apparently higher than in group 1. Particularly, epithelial disruption and mucosal edema were significantly elevated after antigen provocation in group 2.

CONCLUSIONS

These results suggest that chronic eosinophil accumulation is induced by repeated antigen challenges in the nasal tissue, and that once antigen provocation occurs, eosinophils in the tissue are activated and responsible for the amplification of EPR such as vascular permeability and mucosal edema.

Upregulation of the transcription factor GATA-3 in upper airway mucosa after in vivo and in vitro allergen challenge

BACKGROUND

Allergic rhinitis is a complex upper airways disorder characterized by the infiltration of eosinophils and T(H2)-type T lymphocytes. GATA-3 is a novel transcription factor recently shown to regulate IL-5 and, possibly, IL-4 gene expression. We previously reported that GATA-3 is increased within the bronchial mucosa of allergic asthmatic subjects compared with control subjects.

OBJECTIVE

In the present study we set out to determine whether there is also an increased number of cells expressing GATA-3 messenger (m)RNA within the nasal mucosa of patients with allergic rhinitis.

METHODS

Inferior turbinate biopsy specimens were obtained from patients with allergic rhinitis and nonatopic control subjects before and after local allergen provocation in vivo. To assess the contribution of resident cells expressing GATA-3 mRNA, we also performed isolated explant studies in which nasal mucosal tissue from subjects with allergic rhinitis and nonatopic control subjects was cultured in allergen-treated medium. The presence of mRNA coding for GATA-3, IL-5, IL-4, IL-13, and GM-CSF was assessed by using in situ hybridization.

RESULTS

The number of GATA-3 mRNA(+) cells was increased after local allergen provocation in vivo (increase in GATA-3 mRNA(+) cells [mean +/- SEM]: subjects with allergic rhinitis, 11.3 +/- 8.7; control subjects, 1.2 +/- 4.1; P <.05) and in explanted nasal mucosa in vitro (subjects with allergic rhinitis, 10. 2 +/- 3.8; control subjects, 2.7 +/- 4.4; P <.05). The gene expression of GATA-3 was significantly correlated to the numbers of IL-5 (r = 0.87) and GM-CSF (r = 0.79) mRNA(+) cells but not with IL-4 or IL-13 mRNA(+) cells.

CONCLUSION

In summary, the expression of the transcription factor GATA-3 was increased after allergen challenge, and this was evident in the absence of de novo inflammatory cell recruitment. GATA-3 may be a potential target in the treatment of allergic diseases, such as rhinitis.

No increased skin reactivity in subjects with allergic rhinitis during the active phase of the disease

Data on skin reactivity in patients with respiratory atopy without atopic dermatitis are scarce and controversial. Our purpose was to assess whether skin reactivity in patients with seasonal allergic rhinitis varies according to the phase of the disease and the possible release of inflammatory mediators acting on the skin during the pollen season. The volar forearm skin of eleven patients with seasonal allergic rhinitis without atopic dermatitis was challenged with a single exposure to sodium lauryl sulfate. The skin response was evaluated instrumentally over 72 h by transepidermal water loss, capacitance and echogenicity measurements for the assessment of skin damage and the inflammatory response. Tests were performed in winter and repeated in spring in seasonal allergic rhinitis patients, when they showed respiratory symptoms. Fifteen subjects with atopic dermatitis underwent the same experimental procedure in winter as a control population. Baseline and postexposure values were similar both in winter and in spring in seasonal allergic rhinitis patients. After sodium lauryl sulfate challenge, atopic dermatitis patients showed a higher degree of skin barrier damage and inflammation compared to patients with seasonal allergic rhinitis. These findings suggest that subjects with seasonal allergic rhinitis without atopic dermatitis have normal epidermal barrier function and normal skin reactivity during both the inactive and the active phase of the disease. Inflammatory mediators possibly released by mucous membranes during active allergic rhinitis do not influence skin barrier function.

Local production and detection of (specific) IgE in nasal B-cells and plasma cells of allergic rhinitis patients

Allergic diseases are characterized by allergic complaints in the shock organ and specific immunoglobulin (Ig)E in serum. Literature data indicate that the nasal mucosa itself could produce at least a large part of the specific IgE in allergic rhinitis patients. In order to investigate this hypothesis, nasal mucosal biopsies from the inferior turbinate were taken from symptomatic grass pollen allergic rhinitis patients, symptomatic house dust mite allergic rhinitis patients and nonallergic healthy controls, confirmed by radioallergosorbent test and skin-prick test. Immunohistochemical double-staining was performed for B-cells (CD19) with IgE, plasma cells (CD138) with IgE and plasma cells with biotinylated allergens. Significantly more IgE-positive B-cells and IgE-positive plasma cells were found in the nasal mucosa of allergic patients than in that of nonallergic controls. Double staining with biotinylated allergens and plasma cells showed allergen-positive plasma cells in the nasal mucosa of allergic patients and no allergen-positive plasma cells in the nasal mucosa of nonallergic patients. Blocking experiments using polyclonal antibodies directed against IgE showed a significant reduction in the number of allergen-positive cells in contrast to experiments using polyclonal antibodies directed against IgG, IgA or IgM. This study describes new evidence that specific immunoglobulin E is produced locally in the nasal mucosa in patients with seasonal allergic rhinitis and perennial allergic rhinitis, but not in nonallergic controls.

Epithelial changes in seasonal allergic rhinitis throughout the year: evidence of coexistent air pollution and local secretory IgA deficiency?

To determine possible epithelial changes in seasonal allergic rhinitis, we examined epithelial cells in cytology swab preparations of 38 non-smoking patients, exclusively sensitized to grass pollen, throughout the year, and surgical material of 8 patients. Cytologically, we found a marked goblet cell hyperplasia during the period of grass pollen exposure, while meta- and dysplasia were found throughout the year. Immunohistochemically, a lack of secretroy IgA in the altered epithelium was detected. These results were not obtained in the control group of 60 healthy non-smokers. Since we have recently found the same epithelial changes of meta- and dysplasia in smokers, these findings may point to non-specific toxic damage of the nasal epithelium possibly caused by other air pollutants. The altered epithelium may lead to an impairment of the local secretory IgA defence system and thereby to an increased allergen uptake.

Molecular pathology of allergic disease. II: Upper airway disease

Allergic upper airway diseases such as allergic rhinitis and chronic sinusitis are an increasing problem. Although the pathogenesis remains elusive, an individual's genetic predisposition as well as exposure to the allergen are currently considered factors in their development. Clinical symptoms of sneezing, rhinorrhea, and congestion are primarily a consequence of granulocyte release of chemical mediators such as histamine, prostanoids, and leukotrienes as well as the infiltration of inflammatory cells. Observations subsequent to allergen provocation are comparable to natural exposure and as such much of our understanding of allergic responses is derived from this model. A prominence of CD4(+) T cells and eosinophils, synthesis and release of T(H)2 cytokines, and the coordinate expression of chemokines and adhesion molecules are all characteristic of the allergic response observed in rhinitis and sinusitis. Corticosteroids and immunotherapy target these inflammatory processes and have been observed to successfully reduce and shift the predominantly T(H)2 environment toward T(H)1 cytokine expression. As our understanding of the pathophysiologic features of allergic upper airway disease improves, as well as the relationship between their development and that of lower airway disease, new strategies of diagnosis and treatment will allow for more effective modulation of the allergic process and associated morbidity.

Minimal persistent inflammation is also present in patients with seasonal allergic rhinitis

BACKGROUND

The allergic reaction is characterized by an inflammatory response, which is correlated to the allergen exposure, and is detectable in mite allergic patients, even when symptoms are absent.

OBJECTIVE

The study was aimed at assessing the presence of inflammation in patients with pollen allergy during a long observation period.

METHODS

Six patients, sensitized only to Betula alba, were enrolled. Evaluated parameters were (1) nasal symptoms, (2) inflammatory markers (ie, neutrophil and eosinophil number and intercellular adhesion molecule-1 expression on nasal epithelial cells), and (3) pollen count. Patients were examined during the pollen season every 4 days for 40 days and were observed 3 times after the pollen season.

RESULTS

A significant inflammatory reaction was evident throughout the pollen season, even during the days with a low pollen count and low or absent symptoms.

CONCLUSIONS

The results of this study indicate that the global therapeutic strategy for allergic rhinitis should be revised and targeted to inflammatory phenomena rather than to symptoms alone.

Evaluation of acoustic rhinometry in a nasal provocation test with allergen

BACKGROUND

The objective was to validate acoustic rhinometry (AR) in a nasal challenge with allergen.

METHODS

Nasal response to allergen provocation was based on clinical and symptom scores, cross-sectional changes of the nasal mucosa as measured by AR with the Rhinoklack system, and peak nasal inspiratory flow (PNIF), in atopic and nonatopic volunteers.

RESULTS

After allergen challenge, mean variation in minimal cross-sectional area (deltaMCA), as measured by AR, or in peak nasal inspiratory flow (deltaPNIF) in nonatopic volunteers, was -0.4+/-14.3% and 5.2+/-15.7%, respectively, compared to baseline. This allowed the determination of a reaction threshold of -29% for deltaMCA and of -26% for deltaPNIF. All but one of the 30 atopic patients reached the AR reaction threshold, whereas all patients reached the PNIF reaction threshold. AR and PNIF closely correlated with clinical and symptom scores for nasal congestion, since there was no significant difference at reaction threshold between both methods.

CONCLUSIONS

In an allergen provocation test, AR appears to be as specific and sensitive as peak nasal inspiratory flow, with the advantage of being independent of the patient's active cooperation. Discrepancies between both methods emphasize the role of nasal cavity anatomy in measuring nasal congestion by AR.

Allergen-induced eosinophil cytolysis is a primary mechanism for granule protein release in human upper airways

Cytotoxic eosinophil granule proteins are considered important in the pathogenesis of allergic airway diseases such as rhinitis and asthma. To explore the cellular mechanisms behind eosinophil granule release in human allergic airways, 16 symptom-free patients with seasonal allergic rhinitis were challenged daily with allergen during 1 wk. Nasal lavage samples and biopsies, obtained before and 24 h after the last allergen exposure, were processed for immunohistochemical and electron microscopic analysis. The allergen challenges produced nasal symptoms, marked tissue eosinophilia, and an increase in lavage fluid levels of eosinophil cationic protein (ECP). The nasal mucosa areas with intense extracellular immunoreactivity for ECP were associated with abundant free eosinophil granules. Electron microscopy confirmed the free granules and revealed that all mucosal eosinophils were involved in granule release, either by cytolysis (33%) or piecemeal degranulation (PMD) (67%). Resting or apoptotic eosinophils were not observed. Cytolytic eosinophils had less signs of intracellular granule release (p < 0. 001) and a higher content of intact granules (p < 0.001) compared with viable eosinophils in the same tissue. This study demonstrates eosinophil cytolysis (ECL) as a distinct mechanism for granule mediator release in human allergic airway mucosa. The nature and extent of the ECL and its product (i.e., protein-laden extracellular granules) indicate that allergen-induced cytolysis is a primary and major mechanism for the release of eosinophil proteins in human allergic airway inflammation in vivo.

Monocyte chemotactic proteins in allergen-induced inflammation in the nasal mucosa: effect of topical corticosteroids

BACKGROUND

Human allergen-induced rhinitis is associated with the recruitment and activation of inflammatory cells, particularly eosinophils and CD4(+) T cells, in the nasal mucosa. Chemokines are inflammatory mediators capable of attracting specific inflammatory cell populations. Monocyte chemotactic proteins (MCPs), a subfamily of CC chemokines, have been shown to induce chemotactic activity particularly in eosinophils, T cells, and monocytes under in vitro assay conditions.

OBJECTIVE

To assess the contribution of MCPs in the recruitment of inflammatory cells in vivo, we investigated the allergen-induced late response in subjects with allergic rhinitis.

METHODS

Patients were randomized to receive a 6-week treatment with either topical corticosteroid (n = 6) or a matched placebo (n = 6). Nasal inferior turbinate biopsy specimens were obtained from all subjects before and during allergen-induced late responses. By using immunocytochemistry, tissue sections were examined for the presence of MCP-1, MCP-3, and MCP-4 and for the phenotype of infiltrating cells within the nasal mucosa. In addition, double sequential immunocytochemistry was used to confirm the phenotype of MCP-immunoreactive positive cells. Furthermore, the effect of topical corticosteroids on the expression of MCPs and on the cellular infiltrate was also examined.

RESULTS

MCP-1, MCP-3, and MCP-4 were expressed in all the baseline samples, with prominent staining observed within the nasal epithelium. Biopsy specimens taken after challenge exhibited significant upregulation in the expression of MCP-3 and MCP-4 (P <.001). On the other hand, this increase in response to allergen was reduced in patients pretreated with topical corticosteroids. Colocalization experiments revealed that the majority of MCP+ cells in the subepithelium were macrophages, followed by T cells and eosinophils.

CONCLUSION

Our results demonstrate that allergen-induced rhinitis is associated with an increased expression of MCP-3 and MCP-4, which may be closely related to the influx of inflammatory cells and may thus contribute to the pathogenesis of allergic rhinitis.

Basophil histamine release, IgE, eosinophil counts, ECP, and EPX are related to the severity of symptoms in seasonal allergic rhinitis

BACKGROUND

Serum specific IgE, basophil histamine release, and blood eosinophil parameters are associated with allergic rhinitis, but investigations of the relationship to the severity of allergic symptoms are few and conflicting. Our study aimed to investigate the seasonal changes in the following laboratory tests: specific IgE, basophil histamine release, eosinophil counts, and serum and plasma eosinophil cationic protein (ECP) and eosinophil protein X (EPX), and to analyze, in detail, the relationship of each individual test to the severity of symptoms in rhinitis patients allergic to both birch and grass pollen.

METHODS

The above tests were performed on blood samples obtained from 49 allergic rhinitis patients during the birch-pollen season, during the grass-pollen season, and after the seasons. Symptom-medication diaries were filled in during both pollen seasons. We used partial least square (PLS) analysis to establish an optimal statistical link between the symptom score and medication and the laboratory tests, in an investigator-independent way.

RESULTS

Increases in specific IgE, basophil histamine release, eosinophil counts, serum ECP and EPX, and plasma EPX were observed from the birch-pollen season to the grass-pollen season, followed by a decrease from the grass-pollen season to after the pollen seasons, except for the specific IgE. No seasonal changes in plasma ECP and total IgE were seen. The PLS analysis found a relationship between symptom score and medication and the aggregate laboratory tests (F-test value 40.2, correlation 0.34 for the cumulative relation). However, the variation in laboratory tests could explain only half of the total variation in symptoms and less than a quarter of the total variation in medication. The symptom score and, to a minor degree, medication were especially correlated with the basophil histamine-release results, with a decreasing relevance of specific IgE, eosinophil counts, total IgE, serum and plasma EPX, and serum ECP. Plasma ECP was not related to the symptom score and medication.

CONCLUSIONS

A significant relationship between the severity of allergic rhinitis and various allergic inflammatory markers was found but could account for only a minor part of the variation in the patients' evaluation of their disease.

Lung air spaces: MR imaging evaluation with hyperpolarized 3He gas

Thirty-two magnetic resonance imaging examinations of the lungs were performed in 16 subjects after inhalation of 1-2 L of helium 3 gas that was laser polarized to 10%-25%. The distribution of the gas was generally uniform, with visualization of the fissures in most cases. Ventilation defects were demonstrated in smokers and in a subject with allergies. The technique has potential for evaluating small airways disease.

Increase in IL-8, IL-10, IL-13, and RANTES mRNA levels (in situ hybridization) in the nasal mucosa after nasal allergen provocation

BACKGROUND

Allergic inflammation is regulated by the local production and release of several cytokines.

OBJECTIVES

This study was designed to assess the changes in mRNA cytokine-positive cells after allergen provocation and to compare these cytokines with tissue eosinophilia as a marker of allergic inflammation.

METHODS

A grass pollen allergen provocation study was conducted in autumn, out of the hay fever season. Nasal mucosal biopsy specimens were taken before provocation and 1 hour, 24 hours, and 1 week after allergen provocation. Eosinophils and mRNA-positive cells (in situ hybridization for IL-2, IL-3, IL-4, IL-5, IL-6, IL-8, IL-10, IL-13, IFN-gamma, RANTES, and TNF-alpha) were assessed in the biopsy specimens.

RESULTS

After allergen provocation, an increase in cell number was found for eosinophils and cells expressing mRNA for the chemokines IL-8 and RANTES and for the TH2 cytokines IL-10 and IL-13. Significant correlations were found between eosinophils and RANTES and eosinophils and IFN-gamma in the early phase and between eosinophils and IL-5 and eosinophils and RANTES in the late phase. The increase in eosinophils and IL-10 and IL-13 mRNA-positive cells could still be observed 1 week after allergen provocation.

CONCLUSIONS

Nasal allergen provocation induced significant tissue eosinophilia and a significant increase in IL-8, IL-13, and RANTES mRNA-positive cells. A significant increase in eosinophils and IL-10 and IL-13 mRNA-positive cells compared with baseline can still be observed 1 week after a single allergen provocation.