The Role of Thymidine Phosphorylase in the Pathogenesis of Allergic Rhinitis

The activity and distribution of thymidine phosphorylase (TP) in the nasal mucosa of patients with nasal allergy was examined and compared with those in healthy subjects. TP activity was analyzed by spectrophotometry and expression was examined by immunoblotting and immunohistochemical staining using a monoclonal antibody specific to TP. The expression level of TP detected by immunoblotting showed a correlation with the activity detected by spectrophotometry. In nasal mucosa obtained from patients with nasal allergy, the level of TP was significantly higher than that from normal subjects. Eosinophils, basal cells in mucosal epithelium and fibroblasts in nasal mucosa obtained from patients with nasal allergy were stained with anti-TP monoclonal antibody. Strong staining of eosinophils present in nasal discharge was observed. The present results indicate that an increased number of TP-expressing cells, especially eosinophils in nasal mucosa, might be associated with the pathogenesis of nasal allergy.     

白介素12基因治疗对变应性鼻炎小鼠嗜酸粒细胞及白介素5的影响

目的 探讨经鼻局部给予脂质体包裹的白细胞介素(interleukin,IL)12基因治疗对变应性鼻炎(allergic rhinitis,AR)小鼠模型鼻黏膜、外周血和骨髓中嗜酸粒细胞(eosinophils,EOS)的调节作用及相关因子IL-5的影响.方法 采用6～8周雄性BALB/C小鼠,随机分成AR组、基因治疗组和健康对照组,每组12只.卵清蛋白(ovalbumin,OVA)致敏激发建立AR模型,治疗组激发前经鼻给予脂质体包裹的pGEG.m IL-12,对照组用生理盐水代替.三组分别用HE染色计数鼻黏膜中EOS的数量,用瑞氏染色计数骨髓涂片中EOS数,以流式细胞仪检测外周血中的EOS数;免疫组化染色检测鼻黏膜和骨髓中IL-5的表达,以ELISA方法检测血清中的IL-5含量.采用单因素方差分析进行统计学处理.结果 三组小鼠中,各检测指标在各组之间的差异均有统计学意义(P值均<0.01).两两比较发现,基因治疗组鼻黏膜EOS数为(4.6±2.6)个/高倍镜视野,低于AR组的(26.5±9.8)个/高倍镜视野,差异有统计学意义(P<0.05);IL-5阳性细胞数[(3.0±1.3)个/高倍镜视野]也低于AR组[(17.6±6.4)个/高倍镜视野],差异有统计学意义(P<0.05);骨髓涂片中EOS(0.040±0.029)低于AR组(0.086±0.014),差异有统计学意义(P<0.05),IL-5阳性细胞数(0.035±0.012)也低于AR组(0.083±0.025),差异有统计学意义(P<0.05).基因治疗组外周血中EOS(0.124±0.031)低于AR组(0.184±0.079),差异有统计学意义(P<0.05),IL-5[(29.51±6.68)pg/ml]也低于AR组[(56.58±16.80)pg/ml],差异有统计学意义(P<0.05).结论 经鼻局部给予脂质体包裹的pGEG.m IL-12能够通过降低骨髓、外周血和鼻黏膜中IL-5的表达,进而减少骨髓、外周血和鼻黏膜中EOS的数量,IL-12基因治疗可能为呼吸道变应性炎症开辟一种新的治疗途径.     

Monoclonal antibody-detectable carbohydrate epitopes of human nasal secretions are differentially expressed in tissue and diseases

To study the differential carbohydrate expression of airway secretions, we have produced a series of monoclonal antibodies that recognize human nasal secretory cell products. Mice were immunized with purified nasal secretion from patients with chronic sinusitis (CS) and hybridomas were selected by ELISA and immunohistochemical staining of the maxillary sinus mucosa from patients with CS. Eighteen antibodies were obtained. Antibody HCS 18 reacted with epithelial goblet cells, antibody HCS 4, 5, 6, and 16 stained submucosal gland cells, and antibody HCS 13 and 15 reacted with epithelial goblet cells, submucosal gland cells, and endothelial cells of vessels. The other eleven antibodies recognized epithelial goblet cells and submucosal gland cells. Cross-reactivity of these antibodies with secretory cells in other organs and in other species was determined and the different staining pattern was observed between upper and lower airway tissue, suggesting that secretory products from upper and lower airways may be different. Reactivity of the antibodies with nasal secretory cells was also examined in patients with perennial allergic rhinitis (AR) and normal subjects. Antibody HCS 18 weakly reacted with nasal glands in the tissue from CS and AR patients, but minimally reacted with gland cells in normal tissue. Antibody HCS 1 and 7 partially lost their reactivity with nasal epithelium of inferior turbinate from normal subjects and AR patients. These antibodies may be useful to study nasal secretions.     

Cytolysis of eosinophils in nasal secretions

It is still unknown how eosinophils degranulate in nasal mucus. Currently, cytolysis is being reevaluated as the mode of degranulation of eosinophils in allergic nasal mucosa. To examine whether eosinophils migrating to the nasal mucus degranulate by cytolysis, we sampled nasal mucus from 9 patients with nasal allergy and observed it under electron and light microscopes. Both intact and necrotic eosinophils were observed in the nasal mucus. Although the total eosinophil count in the nasal mucus was not correlated with the frequency of sneezes, there was a significant correlation (p = .0025) between the rate of eosinophil lysis and the frequency of sneezes. Whereas extracellular release of eosinophil peroxidase was not detected from the eosinophils with intact cell membranes, large quantities of eosinophil peroxidase were found outside the eosinophils with injured cell membranes. We concluded that eosinophils migrating to the nasal mucus degranulate mainly by cytolysis, and that granular proteins released from the necrotic eosinophils into the nasal mucus are one of the important factors causing hypersensitivity in the nasal mucosa.     

NARES: a model of inflammation caused by activated eosinophils?

Twenty patients were selected on the basis of perennial rhinitis, the absence of allergy and with an eosinophil count higher than 20% of total leucocytes in nasal secretions (NARES). Nasal endoscopy with biopsies from the middle turbinate and sinus CT were performed. Biopsies were processed for histological examination and for immunofluorescence. The clinical progress during treatment was scrutinized. An acute congestive aspect of the nasal mucosa was noted in 4 cases, and micropolyposis in 9 cases. Sinus CT showed opacity of the ethmoidal cells in 87% of cases (maxillary sinuses: 75%; frontal sinus: 46%; sphenoidal sinus: 31%). An eosinophilic infiltrate of the nasal mucosa was constituted in 9 cases: In 6 cases, the cells expressed the Fc epsilon RII receptor, recognized by the monoclonal antibody Bb10. Anti-H1 drugs usually failed to result in a clinical improvement and local eosinophilia was not changed. Local corticoids were more effective but not sufficient in some cases, so that oral corticotherapy was needed. Ethmoidectomy was performed in three cases. NARES seems to evolve in three stages: (1) migration of eosinophils from the vessels to the secretions; (2) retention of eosinophils in the mucosa which might be linked to activation of unknown origin; (3) nasal polyposis. Numerous interactions between irritation of the epithelium, release of substance P, and eosinophils, lead to the hypothesis of a neurogenic origin of NARES.     

Pathophysiological condition of the nose of asthmatic children with subclinical nasal allergy

Nasal mucociliary transport time, nasal hypersensitivity to histamine, the number of basophils and eosinophils in the superficial mucous layer of the inferior turbinate, and the amount of histamine in the nasal secretion were measured in the asthmatic children with subclinical nasal allergy (asthma group). These results were compared with those in nasal allergic patients with nasal symptoms (nasal allergy group). Saccharin time did not show any significant difference between the asthma and nasal allergy group. The threshold for nasal hypersensitivity to histamine was significantly higher in the asthma group than in the nasal allergy group. Accumulation of basophils and eosinophils in the superficial mucous layer of the inferior turbinate were observed in both groups. There was a statistical correlation between the number of basophils and the number of eosinophils in the superficial nasal mucosa in the nasal allergy group, but not in the asthma group. These data suggest that basophilic cell function in the superficial mucous layer in the nose is of greater significance in the development of nasal symptoms in response to nasal allergy than either mucociliary activity or nasal mucosal hypersensitivity to histamine.     

白细胞介素5及嗜酸细胞在变应性鼻炎患者免疫治疗前后的变化

目的探讨特异性免疫治疗(specific immunotherapy,SIT)前后变应性鼻炎(AR)患者血清中白细胞介素5(interleukin-5,IL-5)及嗜酸细胞(eosinophils,Eos)的变化及IL-5在AR发病中的作用。方法采用酶联免疫吸附法检测66例AR组患者SIT前后和对照组35例血清中IL-5含量的变化;采用HE染色方法检测SIT前后30例AR患者和对照组35例鼻黏膜中Eos浸润情况。结果 SIT前AR患者血清中IL-5含量(56.32±19.30)ng/L明显高于对照组(15.12±8.40)ng/L和SIT 1年后AR患者(19.04±10.80)ng/L;SIT前AR患者鼻黏膜中Eos浸润数26.08±8.90/HP明显高于对照组3.74±2.40/HP和SIT 1年后AR患者4.94±2.78/HP。结论 IL-5可能通过调节Eos而参与AR的发病机制及病情发展变化。     

Eosinophil infiltration and activation in nasal polyposis

Conclusions. Infiltration and activation of eosinophils is a characteristic of nasal polyposis. Allergic reaction is a risk factor for the accumulation of eosinophils in this disease. T-cell-derived interleukin 5 (IL-5) and autosecretion of IL-5 from activated eosinophils may be causative reasons for the extension and persistence of eosinophil inflammation. Objectives. To investigate whether eosinophils were accumulated and activated in nasal polyposis, and the roles of IL-5, eotaxin, and T cells in this process. Materials and methods. A retrospective study was conducted on 17 tissue samples from patients with nasal polyposis with allergy and 26 cases of non-allergic polyposis. Immunohistochemical staining by specific antibodies was carried out using the alkaline phosphatase anti-alkaline phosphatase method and the avidin-biotin complex technique.Results. The number of EG1-positive cells (pan eosinophil marker) was similar to the number of EG2-positive cells (activated eosinophil marker) in all tissue samples, although EG1- and EG2-positive cells were richer in allergic patients than those in non-allergic patients. Both EG1- and EG2-positive cells were correlated with CD3-positive cells (pan T cell marker) and IL-5-producing cells in allergic or non-allergic polyposis. A large proportion of IL-5 producing cells were eosinophils. Eotaxin protein was detected in all tissue samples and dominantly located in epithelial cells. Eotaxin expression between allergic and non-allergic subjects was not significantly different.     

Expression of Syk is associated with nasal polyp in patients with allergic rhinitis

OBJECTIVE: Numerous signalings are involved in allergic inflammation. The non-receptor protein tyrosine kinase, Syk, is widely expressed in immune-potentiated cells and plays critical roles in initiating signal transduction in response to the activation of cytokine, chemokine and other types of receptors. It has been hypothesized that Syk expression in allergic nasal mucosa and polyps with allergy is different from non-allergic mucosa, and that changes in Syk expression contribute to the activation of allergic reactions. METHODS: We examined whether the expression of Syk is found in allergic nasal mucosa and polyps. We investigated the expression of Syk in 46 nasal mucosa and polyps (14 samples from patients with allergic rhinitis and 32 samples with non-allergic chronic sinusitis) using an immunohistochemical technique. RESULTS: Allergic polyps had more Syk positive cells than non-allergic polyps. Syk positive cells were determined to mainly be eosinophils. There was no difference in Syk expression in the lamina propria and nasal gland between allergic mucosa and non-allergic mucosa. CONCLUSION: Eosinophils in allergic polyps receive an intracellular signal, although the signal is not able to determine the function in the present state. Syk appears to be a promising target molecule for anti-allergic inflammation in allergic rhinitis.     

Significance and expression of transforming growth factor beta in human nasal polyp tissue]

OBJECTIVE: To explore the pathogenesis of nasal polyposis and the expression of transforming growth factor beta (TGF-beta) in human inflammatory nasal polyps. METHODS: TGF-beta 1-3 in nasal polyp tissues and inferior turbinate mucosa of twenty-five polyposis patients were detected with immunohistochemistry alkaline phosphatase and anti-alkaline phosphatase (APAAP) method. The inferior turbinate mucosa of eight healthy volunteers were selected as control. Six polyp tissues were estimated with double immunolabeling and Western-blot analysis to compare the characterization of the TGF-beta isoforms expression and the proportion of macrophages and eosinophils in nasal polyp tissues. RESULTS: The expression of TGF-beta 1-3 in nasal polyps was significantly higher than that in nasal mucosa and indetecable in nasal mucosa from healthy volunteers; TGF-beta 1 was the main isoform detected in nasal polyps; TGF-beta positively was accompanied by numerous macrophage and eosinophil infiltration. CONCLUSIONS: TGF-beta mainly TGF-beta 1 is strongly expressed in nasal polyps and its mucosa, where it could be produced by macrophages and eosinophils. TGF-beta could induce modification of epithelium and connective tissue and therefore be involved in the pathogenesis of nasal polyposis.     

Study of eosinophil activation in nasal mucosa in patients with perennial nasal allergy: effects of CO2 laser surgery

Carbon dioxide (CO2) laser surgery has been shown to be clinically effective in the treatment of nasal allergy. To investigate the mechanisms of eosinophil infiltration and activation underlying the therapeutic effects of CO2 laser surgery, we examined changes in the cytological profile of nasal mucosa after surgery. Twenty-two patients with perennial nasal allergy against house-dust mites underwent two or three rounds of laser surgery at 1-month intervals on an outpatient basis. The following parameters were evaluated at each visit: (i) improvement of clinical symptoms (nasal obstruction, rhinorrhea, and sneezing), (ii) percentage of infiltrating eosinophils in nasal mucosa, and (iii) the degree of EG2+ cells and intracellular adhesion molecule 1 (ICAM-1) expression by immunocytochemistry. All clinical symptoms significantly decreased after surgery. Significant reductions in eosinophil infiltration (p < 0.01) and the percentage of EG2+ cells (p < .005) were observed also. However, the degree of ICAM-1 expression in epithelial cells was not changed. These results suggest that CO2 laser surgery partially reduced the allergic reactions, leading to improvement of clinical symptoms.     

A study of infiltrated cells in the maxillary mucosa in nasal allergy and chronic sinusitis

The cloudiness of the maxillary sinus in Waters-view is 37% in patients with nasal allergy. The pathogenesis of this cloudiness has not fully understood yet; is it due to the type- I allergic reaction, or secondary maxillary sinusitis? To clarify the pathology, we studied the infiltrated cells in 37 mucosae of the maxillary sinus in which X-ray revealed an abnormal shadow. Samples were also taken from 9 antrums with chronic sinusitis, and 18 and 4 nasal mucosae form the inferior turbinate with nasal allergy and sinusitis, respectively. Each specimen were fixed with Carnoy solution and formalin, and were stained with Hematoxylin & Eosin, and with Alcian blue & Safranin. Numbers of formalin sensitive and resistant mast cells and eosinophils were determined in the epithelium, and superficial and deep layers of the lamina propria, respectively. The population of both mast cells in each compartment was not different between nasal allergy and maxillary sinusitis both in the nasal and maxillary mucosae. The number of eosinophils in the maxillary and nasal epithelial significantly increased in nasal allergy compared with sinusitis. These results suggested that type-I allergic reaction might occur in the maxillary mucosa as well as nasal mucosa in patients with nasal allergy.     

Measurement of the blood flow of the nasal mucosa by the hydrogen clearance method

The tissue blood flow of the nasal mucosa in normal subjects and patients with nasal allergy was studied by the hydrogen clearance method. The flow in the inferior turbinate in normal subjects and patients with nasal allergy did not differ. The test results were highly reproducible and were almost the same in different anterior parts of the inferior turbinate. The effects of nasal spray with vasoconstrictor and nasal provocation by an allergen-containing paper disc on the blood flow of the inferior turbinate were examined in normal subjects and patients with nasal allergy. The flow decreased remarkably after spray with vasoconstrictor. The flow also decreased remarkably in the mucosal membrane close to the area of contact of the allergen disc, whereas it increased at the area 10 mm away from the disc. The hydrogen clearance method is useful for clinical studies of nasal circulation.     

Expression of annexin A1 in normal and chronically inflamed nasal mucosa

OBJECTIVE: To examine the expression pattern of annexin A1 in normal and chronically inflamed nasal mucosa to investigate its possible role in nasal inflammation. DESIGN: Immunohistochemical analysis. SUBJECTS: Samples of middle turbinates from 5 healthy subjects and 5 patients with perennial rhinitis, and samples of nasal polyps from 7 patients. INTERVENTIONS: Annexin A1 expression was examined with a standard immunohistochemical protocol on paraffin-embedded sections. RESULTS: Annexin A1 was highly expressed by ciliated cells, where it was concentrated on the apical surface and within the cilia. Goblet cells and nondifferentiated basal epithelial cells did not stain. In the glands of the lamina propria, intense staining was found in the cytoplasm and in the nuclei of the cells in the duct epithelium, whereas acinar cells did not stain. Intense cytoplasmic staining was observed in infiltrating polymorphonuclear cells and macrophages. No differences in the pattern or the level of expression of annexin A1 were found in the epithelial cells and glands of normal and chronically inflamed (perennial rhinitis or polyps) nasal mucosa. CONCLUSION: These results suggest that the expression of annexin A1 in respiratory epithelium of nasal mucosa is related to cell type and differentiation status of the cells and is not significantly altered by inflammatory diseases.     

Eotaxin基因和趋化因子受体3在变应性鼻炎大鼠模型鼻腔黏膜和骨髓中的表达及意义

目的：探讨Eotaxin（嗜酸粒细胞趋化因子）基因和趋化因子受体3（CCR3）在变应性鼻炎（AR）大鼠模型鼻腔黏膜和骨髓中的表达及其意义。方法：采用6～8周龄雄性SD大鼠20只,随机分成实验组（AR组）和对照组,每组10只,以卵清蛋白致敏激发制成AR模型,瑞特染色计数骨髓涂片和外周血涂片中白细胞比例,免疫组织化学技术检测骨髓中CCR3的表达;制备大鼠鼻腔黏膜组织病理标本,苏木精-伊红染色,原位分子杂交方法检测鼻腔黏膜中Eotaxin mRNA的表达,免疫组织化学技术检测Eotaxin在鼻腔黏膜中的表达。结果：AR组骨髓涂片中嗜酸粒细胞比例显著高于对照组（P〈0．01）,AR组外周血涂片中嗜酸粒细胞比例显著高于对照组（P〈0．01）;与对照组比较,AR组大鼠鼻腔黏膜中Eotaxin阳性细胞数与EotaxinmRNA表达明显增强（P〈0．01）,且二者呈正相关性（r=0．804,P〈0．01）。AR组Eotaxin的表达与鼻腔黏膜嗜酸粒细胞的数量呈显著正相关（r=0．795,P〈0．01）。AR组骨髓涂片中CCR3阳性细胞比例显著高于对照组（P〈0．01）,AR组骨髓涂片中CCR3阳性细胞比例和外周血嗜酸粒细胞比例呈显著正相关（r=0．736,P〈0．05）。结论：AR组中Eotaxin和CCR3表达增强,为嗜酸粒细胞从骨髓快速募集到鼻腔黏膜提供了可能。     

VCAM-1表达在上下呼吸道一致性的研究

目的：探讨血管内皮细胞黏附分子（VCAM-1）在呼吸道变应性炎症患者中的表达和意义。方法：将39名患有变应性鼻炎并哮喘的患者和21例仅患有变应性鼻炎的患者分成两组,取鼻腔黏膜和支气管黏膜进行活组织病理检查,并用免疫组织化学的方法对VCAM-1的表达进行检测。结果：变应性鼻炎并哮喘组支气管黏膜中嗜酸粒细胞数显著高于变应性鼻炎组（t=12．81,P〈0．01）,变应性鼻炎组鼻腔黏膜中VCAM-1阳性细胞比例与变应性鼻炎并哮喘组相比差异无统计学意义。变应性鼻炎并哮喘组支气管黏膜中VCAM-1阳性细胞比例显著高于变应性鼻炎组（t=9．43,P〈0．01）,变应性鼻炎并哮喘组支气管黏膜中VCAM-1阳性细胞比例和支气管黏膜嗜酸粒细胞数呈显著正相关（r=0．788,P〈0．01）。结论：VCAM-1表达的上调,导致呼吸道变应性炎症的蔓延。     

Interferon Gamma Expression in Human Nasal Polyps

One feature among nasal polyps (NPs) is the predominance of lymphocytes and eosinophils. We hypothesize that elevated levels of interferon gamma (IFN-γ) activate lymphocytes and eosinophils within the NP microenvironment. Nasal polyps were evaluated for distribution and levels of IFN-γ specimens from 27 patients with nasal polyposis and 4 controls. Immunohistochemical study revealed IFN-γ staining of eosinophils, glandular cells, and epithelium (27 of 27 patients). ELISA analysis indicated elevated IFN-γ levels in total NP tissues (25.6 ± 7.23 pg/mg total protein [TP]) compared with controls (16.27 ± 6.54 pg/mg TP). Three subpopulations were identified based on IFN-γ levels: low IFN-γ group (10.7 ± 5.51 pg/mg TP); medium IFN-γ group (25.70 ± 5.90 pg/mg TP); and high IFN-γ group(52.58 ± 10.29 pg/mg TP). The latter levels were approximately 3.5 times the control levels (P < 0.0025). Patients with previous polypectomy surgery showed higher levels of IFN-γ compared with controls(P < 0.0423). A trend was found with increased IFN-γ levels and allergy, asthma, and topical steroid use.     

Immunohistochemical distribution of fibronectin in the mucosa with chronic sinusitis

The distribution of fibronectin (FN) in operative specimens of maxillary sinus mucosa from 35 patients with chronic sinusitis was examined immunohistochemically. Mouse monoclonal antibody to human FN was used for the peroxidase-antiperoxidase staining technique. FN was found in most of the serous cells and in some (about 10%) of the mucous cells in the nasal glands, and also in the nasal fluid in the lumina. It was not found elsewhere, be it in the epithelial cells, the basement membrane, or the interstitial tissue, except in two patients. These results suggest that FN is produced in the nasal glands and secreted into the nasal fluid in the maxillary sinus in chronic sinusitis.     

变应性鼻炎鼻黏膜组织重塑的研究

目的:探讨变应性鼻炎(AR)鼻黏膜组织是否存在重塑,检测与组织重塑密切相关的转化生长因子β1(TGF-β1)、基质金属蛋白酶9(MMP-9)及其组织抑制物1(TIMP-1)在AR患者鼻黏膜组织中的表达情况。方法:15例单纯性鼻中隔偏曲患者为对照组,16例鼻中隔偏曲伴轻度间歇性AR的患者为轻度AR组,12例鼻中隔偏曲伴重度持续性AR的患者为重度AR组。均取中鼻甲黏膜组织,苏木精-伊红染色观察嗜酸粒细胞浸润情况并测定上皮损伤情况;AB-PAS法计数杯状细胞数,MT法测定细胞外基质沉积面积百分比,ELISA测定组织中TGF-β1、MMP-9及TIMP-1的表达。结果:①对照组无明显嗜酸粒细胞浸润,轻度、重度AR组嗜酸粒细胞浸润均较对照组明显增多(均P<0.05);②轻度AR组中仅上皮细胞损伤1级比对照组明显(P<0.05),重度AR组上皮损伤1、2、3级均比对照组明显(均P<0.05);③轻度、重度AR组杯状细胞数明显多于对照组(均P<0.05);④与对照组相比,轻度AR组胶原沉积面积增多,但差异无统计学意义(P>0.05);重度AR组胶原沉积面积比对照组明显增多(P<0.05);⑤TGF-β1、MMP-9及TIMP-1在轻度、重度AR组黏膜中的表达均较对照组增高(均P<0.05);重度AR组TGF-β1和TIMP-1的表达均比轻度AR组增高(均P<0.05)。结论:AR的鼻黏膜组织发生了重塑,表现为上皮细胞损伤、杯状细胞化生、细胞外基质沉积,重度AR患者的鼻黏膜重塑更强、更广泛,TGF-β1、MMP-9、TIMP-1积极参与了AR鼻黏膜组织的重塑。     

Distribution of 3-nitrotyrosine in the nasal polyps of atopic patients

OBJECTIVE: To investigate whether formation of nitrotyrosine in the nasal polyps of atopic patients occurs. STUDY DESIGN: A nonrandomized, retrospective, controlled qualitative and quantitative study. METHODS: Nasal polyp tissue samples were acquired from 12 atopic patients. Control fragments of nasal mucosa were taken from 10 patients undergoing corrective surgery of the nasal septum. For routine histologic examinations, hematoxylin-eosin staining was used. Low-magnification microscopy was designed to yield pathologic characteristics and high magnification to quantify the number of eosinophils in the subepithelial connective tissue. Presence of nitrotyrosine was assessed by immunohistochemical method. RESULTS: Hematoxylin-eosin staining revealed presence of numerous eosinophils in the epithelium and in the subepithelial connective tissue. All polyps were characterized by epithelial damage. Nitrotyrosine was present in the eosinophils, in the ciliated cell, and in cells of the damaged epithelium. Goblet cells, glands, and vessels were found to be negative. No significant differences concerning the localization of nitrotyrosine were recognized among the examined nasal polyps. CONCLUSIONS: Nitrotyrosine immunohistochemical staining in nasal-polyp tissues suggested the existence of progressive epithelium injury caused by peroxynitrite. Consequences of peroxynitrite formation in eosinophils remain to be precisely established. The lack of nitrotyrosine in glands and blood vessels indicated that peroxynitrite does not have a significant role in the vascular and glandular dysfunction of nasal polyps.