Role of Allergy in Nasal Polyposis: A Review

A Large Asymptomatic Polyp Originating From the Nasal Septum: A Case Report

A neoplasm was found in the left nasal cavity of a 45-year-old woman during electronic laryngoscopy for reflux pharyngitis. She reported experiencing an occasional slight headache in the left parietal region for 1 to 2 years, which she considered a migraine. Electronic laryngoscopy showed a gray, soft, smooth neoplasm in the left nasal meatus, located near the olfactory region blocking the olfactory clef and compressing the left middle turbinate. The neoplasm was resected at endonasal endoscopic surgery. Histological assessments indicated chronic mucus inflammation and cyst formation. This is a rare case because the polyp was large but asymptomatic and originated from nasal septum.

5-HT7 receptorsare over-expressed in patients with nasal polyps

Nasal polyposis (NP) is an inflammatory disease of the paranasal sinuses and nasal cavity. The primary purpose of our study is to determine the expression of 5-HT7 receptors both in nasal polyps and in healthy tissue in the nasal cavity. The subsequent aim is to compare the expression of 5-HT7 receptors in patients with NP and in inferior turbinate tissue (control).The study included 60 participants (40 with NP and 20 controls) aged 35 to 62 years. Nasal polyp samples were collected from all patients and relative 5-HT7 receptor expression analyses were performed. RT-PCR analysis of nasal polyps and control tissue identified 5-HT7 receptor expression in the nasal cavities of controls. This expression was approximately 67 times higher in nasal polyp tissue than in healthy tissue. Our study identifies the expression of 5-HT7 receptors in the nasal cavity for the first time. It is also the first demonstration of increased 5-HT7 receptor expression in tissue from nasal polyps, which occur in the paranasal sinuses and nasal cavity.

Nasal Polyposis: Role of Allergy on Therapeutic Response of Eosinophil- and Noneosinophil-Dominated Inflammation

Background

It is considered that allergy, at least in some cases, is associated with nasal polyps and affects recurrence rate. Our purpose was to determine the effects of aeroallergen hypersensitization on therapeutic response of eosinophil- and noneosinophil-dominated inflammation.

Methods

Sixty-eight patients were enrolled. Histopathological investigation and a skin-prick test were done and categorized as eosinophil-dominated inflammation with positive (ESPT+) or negative skin test (ESPT-) and nonesoinophil-dominated inflammation with positive (NESPT+) or negative skin test (NESPT-). Patients were treated over 6 weeks with budesonide nasal spray, 400 μg/day. At 0, 3, and 6 weeks after treatment, nasal symptoms, polyp size, nasal and oral peak expiratory flow (PEF) index and overall assessment within and between groups were evaluated and compared.

Results

At 3 and 6 weeks after treatment, the ESPT- group showed the most, and the NESPT+ group showed the least therapeutic improvement. In comparing between the positive and negative skin tests in each histopathology, the positive skin tests tended to have less improvement than the negative skin tests in all variables. The differences increased over time and reached statistical significance at 6 weeks in the PEF index and overall assessment of eosinophil-dominated inflammation (p = 0.004 and 0.033, respectively) and in sneezing score, postnasal drip score, and overall assessment of noneosinophil-dominated inflammation (p = 0.019, 0.035, and 0.013, respectively).

Conclusion

Nonallergic eosinophilic polyps had the best and allergic noneosinophilic polyps had the worst therapeutic response. Within each histopathology, allergic nasal polyps had less therapeutic response than nonallergic nasal polyps. This augmented effect could be caused by concomitant allergic inflammation.

Expression of Cell Cycle Regulatory Proteins and Analysis of Apoptosis in Normal Nasal Mucosa and in Nasal Polyps

Background

The etiopathogenesis of nasal polyps still is to be clarified. Although hyperplasia is a typical feature of these pathological processes, little attention has been paid to specific aspects of cellular growth in polyps. We have evaluated the expression and localization of some of the regulatory proteins that direct the cell through the specific sequence of events culminating in mitosis or apoptosis in nasal polyps.

Methods

Twenty samples of nasal polyps and 20 samples of normal nasal mucosa have been analyzed for apoptotic index by detecting the DNA 3’ OH ends deriving from DNA fragmentation. Moreover, they have been evaluated by immunohistochemical staining for expression of Ki-67, cyclins A and B1, p53, p21, p27, murine double minute clone 2, and Bcl-2.

Results

We have identified a greater proportion of proliferating cells in the lining epithelial cells of the polyps when compared with the normal mucosa as stained with anti–Ki-67 antibodies. An overexpression of p53, MDM2, and Bcl-2 and an increased apoptosis were observed in nasal polyps compared with the normal mucosa, whereas no variation of p27 expression was observed. The p21 and cyclins A and B1 were rarely expressed in both pathological and normal tissue.

Conclusion

The p53-based control system of cell cycle progression appears to be altered in nasal polyps, potentially leading to an abrogation of the DNA damage checkpoint. Evaluation of the expression of the regulatory proteins that direct the cells throughout their cycle in nasal polyps may allow a better understanding of the biological behavior and clinical outcome of these benign pathological entities.

Budesonide-Dependent Modulation of Expression of Macrophage Migration Inhibitory Factor in a Polyposis Model: Evidence for Differential Regulation in Surface and Glandular Epithelia

Macrophage migration inhibitory factor (MIF) is a counterregulatory lymphokine for glucocorticoid action within the immune system. To provide further insights into the way expression of pleiotropically acting MIF is modulated by glucocorticoids, we investigated the influence of the glucocorticoid budesonide on the level of expression of MIF in a model of human nasal polyposis by quantitative immunohistochemical analysis. Ten nasal polyps obtained from surgical resection were maintained for 24 hours in the presence of 3 budesonide concentrations: 10, 50, and 250 ng/mL. As quantitatively demonstrated by computer-assisted microscopy, 50 ng/mL induced an increase in MIF expression in the surface epithelium and a decrease in MIF expression in the glandular epithelium. At the 250 ng/mL dose, the inverse effect was induced. Evidently, surface and glandular epithelia react nonuniformly to the glucocorticoid regarding MIF presence, adding dependence on the cell type to the regulatory network.

Association of HLA-DR3 and HLA-DR4 with Sinonasal Polyposis in Mexican Mestizos

OBJECTIVE: The pathogenesis of sinonasal polyposis (SNP) is not clear; it has been suggested that it is polygenic and multifactorial. The major histocompatibility complex is a useful tool to predict genetic susceptibility to diseases, especially to autoimmune diseases. Since such susceptibility is influenced by ethnicity, it is necessary to have a wide knowledge of the structure of the population to which the patient belongs. The purpose of the study was to determine the association of HLA-DRB1 alleles with sinonasal polyposis in the Mexican Mestizo population.

STUDY DESIGN: We studied the HLA-DR alleles in 34 adult Mexican Mestizo patients with SNP and compared them to those present in 99 healthy controls.

METHODS: Genomic DNA from mononuclear cells was obtained by using the “salting out” technique and high-resolution DNA typing of the HLA-DRB1 alleles was performed after PCR amplification.

RESULTS: We found a statistically significant increased frequency of the HLA-DRB1∗03 allele ( P = 0.03, odds ratio [OR] = 2.9, 95% confidence interval [CI]: 1.0–7.8) and of the HLA-DRB1∗04 allele ( P = 0.009, OR = 2.2, 95% CI: 1.2–4.2) in patients with SNP as compared to controls, and a statistically significant decreased frequency of the HLA-DRB1∗08 allele ( P = 0.01, OR = 0.2, 95% CI: 0.05–0.8).

CONCLUSION: The HLA-DR locus seems to be associated with the genetic susceptibility to develop SNP in Mexicans.

EBM rating: B-2b

Humanized mouse model used to monitor MUC gene expression in nasal polyps and to preclinically evaluate the efficacy of montelukast in reducing mucus production

OBJECTIVES

To determine whether MUC gene expression could be down-regulated in nasal polyps by the leukotriene receptor antagonist montelukast, we developed a system in which nondisrupted human nasal polyps could be successfully implanted into severely immunocompromised mice, and in which the histopathology of the original nasal polyp tissue could be preserved for long periods. In addition, the histopathologic changes in the human nasal polyps were carefully examined to determine the origin of the submucosal glands (SMGs) that develop in true nasal polyps found in the anterior third of the nose.

METHODS

Small, nondisrupted pieces of human nasal polyp tissues were subcutaneously implanted into NOD-scid IL-2rgamma(null) mice. Xenograft-bearing mice were treated with either montelukast or saline solution. Xenografts at 8 to 12 weeks after implantation were examined histologically, and expression of MUC genes 4, 5AC, and 7 was studied in the polyps before implantation and in the 8-week xenograft. Alzet pumps were inserted into the mice, and montelukast (Singulair) was continuously delivered to determine its effect on goblet cell hyperplasia, mucus production, and the enlargement of nasal polyps over an 8-week period.

RESULTS

The xenografts were maintained in a viable and functional state for up to 3 months and retained a histopathology similar to that of the original tissue, but with a noticeable increase in goblet cell hyperplasia and marked mucus accumulation in the SMGs. MUC4 and MUC5AC were significantly increased in the xenograft 8 weeks after implantation, but MUC7 was significantly decreased compared to the preimplantation polyps. Inasmuch as MUC7 is found exclusively in serous glands, the findings suggest that serous glands are not found in polyps in the anterior third of the nose. The histopathologic findings confirm the original findings of Tos et al suggesting that the SMGs are derived from pinching-off of the epithelium of the enlarging polyp following inflammatory changes. These SMGs have the same epithelium as surface epithelium and consist of multiple goblet cells that secrete periodic acid Schiff stain-positive mucin into the interior of the SMGs. A progressive increase in the volume of the xenografts was observed, with little or no evidence of mouse cell infiltration into the human leukocyte antigen-positive human tissue. An average twofold increase in polyp volume was found 2 months after engraftment. Montelukast did not decrease the growth of the xenograft in the 8-week NOD-scid mice, nor did it affect MUC gene expression.

CONCLUSIONS

The use of innate and adaptive immunodeficient NOD-scid mice homozygous for targeted mutations in the IL-2 gamma-chain locus NOD-scid IL-2r gamma(null) for establishing engraftment of nondisrupted pieces of human nasal polyp tissues represents a significant advancement in studying chronic inflammation over a long period of time. In the present study, we utilized this humanized mouse model to confirm our prediction that MUC genes 4 and 5AC are highly expressed and significantly increased over those of preimplanted polyps. The overexpression of these 2 MUC genes correlates with both the goblet cell hyperplasia and the excessive mucus production that are found in nasal polyp xenografts. MUC7, which is primarily associated with the submucosa, as opposed to MUC4 and MUC5AC, which are primarily expressed in the epithelium, was significantly decreased in the nasal polyp xenografts. Montelukast had no significant effect on MUC gene expression in the xenografts. In addition to the MUC gene expression patterns, the histology of the xenografts supports the concept that mucinous glands that are characteristic of true nasal polyps are significantly different from those in the mucosa found in the lateral wall of the nose in patients with chronic sinusitis without nasal polyps. The mucinous glands seen in nasal polyps (which appear to be derived from an invagination of hyperplastic epithelial mucosa containing large numbers of goblet cells) are histologically distinct from the seromucinous glands found in the submucosa of hyperplastic middle turbinates. The data presented here establish a humanized mouse model as a viable approach to study nasal polyp growth, to assess the therapeutic efficacy of various drugs in this chronic inflammatory disease, and to contribute to our understanding of the pathogenesis of this disease.

Comparison of montelukast and mometasone furoate in the prevention of recurrent nasal polyps

BACKGROUND

The aim of our study was to compare the effects of montelukast and mometasone furoate nasal spray on the postoperative course of patients with nasal polyposis.

PATIENTS AND METHODS

Fifty patients diagnosed with nasal polyposis between March 2006 and August 2007 were included in the study. All patients underwent bilateral endoscopic sphenoethmoidectomy and were randomized postoperatively into two groups. Group A (n = 25) received 10 mg montelukast per day and group B (n = 25) received 400 µg mometasone furoate nasal spray twice daily. All patients were followed up for 6 months. Sino-Nasal Outcome Test (SNOT)-22 scores, polyp grades, computerized tomography (CT) scores (Lund-Mackay), eosinophils in peripheral blood and polyp tissue were evaluated before and after surgery.

RESULTS

There was a significant reduction in SNOT-22 scores in both groups throughout the study period. There was a significant difference in the recurrence rate between both groups with a marginal advantage of mometasone furoate nasal spray. Eosinophils in peripheral blood were found to be effective on the recurrence rate (p < 0.05).

CONCLUSIONS

In conclusion, both drugs seem to have a complementary action and further studies are needed to determine which patients should receive which treatment.

Antigen selection in IgE antibodies from individuals with chronic rhinosinusitis with nasal polyps

BACKGROUND

It is generally assumed that all immunoglobulin isotopes develop under antigen selection pressure, leading to dramatic increases in antigen-binding affinity. As activated B cells proliferate, somatic mutations accumulate in the regions of the immunoglobulin gene associated with antigen binding. Emerging evidence from studies investigating mutations in variable region sequences of IgE antibodies suggest that IgE may develop under less selection pressure than other isotypes. Recent studies have focused on IgE mutation patterns in sequences from the blood of allergic individuals. There is, however, little evidence of these patterns in IgE sequences isolated from tissue.

METHODS

Semi-nested reverse-transcription polymerase chain reaction was used to amplify the V region of IgE sequences from nasal tissue of individuals with chronic rhinosinusitis with nasal polyps (CRSwNPs). IgE sequences were analyzed for evidence of antigen selection and compared with previously reported IgE sequences from other inflammatory and allergic disorders and nonallergic individuals.

RESULTS

IgE sequences were successfully amplified from four individuals with CRSwNPs. Of 217 sequences amplified, 38 were unique, 31 of which were from tissue. Identification of the IGHV, IGHD, and IGHJ genes making up each sequence showed overrepresentation of an unusual gene in one individual, but otherwise normal gene usage. Mutation analysis revealed that only 5 of the 31 unique sequences from tissue show clear evidence of antigen selection.

CONCLUSION

With little influence from antigen selection, IgE antibodies are unlikely to be highly specific for antigens. Consequently, these findings have significant implications for the relevance of specific IgE, e.g., Staphylococcus aureus enterotoxin or fungal-specific IgE, in CRSwNP pathogenesis. Whether specific IgE expression is tightly related to pathogenesis or is merely a byproduct of B-cell interactions in local mucosa with colonizing organisms remains unresolved.

Molecular profile of the antrochoanal polyp: up-regulation of basic fibroblast growth factor and transforming growth factor beta in maxillary sinus mucosa

BACKGROUND

Various pathogenetic mechanisms have been proposed to explain the development of antrochoanal polyps (ACPs); however, the cause is still largely unknown. The aim of this study was to characterize the expression and the potential role of a battery of molecular markers in the development of ACPs. A prospective controlled study of a case series was performed.

METHODS

Tissue samples of maxillary sinus mucosa were obtained from 14 patients with ACPs, 17 patients with chronic nonpolypoid maxillary sinusitis, and 4 patients with normal maxillary sinus mucosa; RNAs were extracted from the sinus mucosa, and semiquantitative reverse transcription-polymerase chain reaction was performed for basic fibroblast growth factor, transforming growth factor P, and mucin genes (MUC), MUC5AC, MUC5B, and MUC8, to investigate their expression.

RESULTS

The expression of basic fibroblast growth factor and transforming growth factor beta was significantly higher in ACPs than in chronic rhinosinusitis and healthy mucosa. Meanwhile, the levels of expression of MUC genes were higher in ACPs and chronic rhinosinusitis compared with healthy mucosa.

CONCLUSION

These findings suggest that ACPs may represent an inflammatory reaction caused by overproduction of tissue-derived growth factors in an inductive environment.

Glucocorticoid-induced differential expression of the sialylated and nonsialylated Lewis(a) epitopes and respective binding sites in human nasal polyps maintained under ex vivo tissue culture conditions

We characterized the anti-inflammatory effects of budesonide on the expression of adhesion molecules involving Lewis(a) (Le(a)) epitope, its sialylated derivative (sLe(a)), and their respective binding sites in human nasal polyposis. By computer-assisted microscopy, we quantitatively characterized the level of histochemical expression of L- and P-selectins, sialylated and nonsialylated Le(a) epitopes, and their respective binding sites in both surface epithelium and glandular epithelium of human nasal polyps obtained from surgical resection, maintained under ex vivo tissue culture conditions for 24 hours, and treated or not with budesonide. Intercellular adhesion molecule 1 (ICAM-1) and vascular cell adhesion molecule 1 (VCAM-1) were chosen as methodological controls, because data already published in the literature clearly indicated budesonide-mediated effects on ICAM-1 and VCAM-1 levels of expression. The present data show that budesonide significantly modified the levels of expression of ICAM-1 and VCAM-1, and to a lesser extent that of P-selectin, in the surface and glandular epithelia. Budesonide markedly decreased the levels of expression of the binding sites for both Le(a) and sLe(a), while those of Le(a) and sLe(a) remained globally unchanged. In conclusion, the present study documents that glucocorticoid-induced effects can encompass receptors for Le(a) epitopes different from E- and P-selectins on epithelial cells of human nasal polyps.

Overexpression of Fas-ligand in human nasal polyps

Apoptosis mediated through the Fas/Fas-L system is essential in regulating immune function, developing organs, and conferring immune privilege. To illustrate the role of the Fas/Fas-L system in the pathogenesis of human nasal polyps, we investigated the transcripts and protein level of the Fas-L gene in 8 human nasal polyp tissues and 7 nasal turbinate mucosa specimens using reverse transcription-polymerase chain reaction and Western blotting. Localization of Fas-L was performed with immunohistochemistry. The transcripts of the Fas-L gene were detected at similar levels in both polyps and nasal mucosa. There was a significant overexpression of Fas-L protein on nasal polyps compared to nasal mucosa. Fas-L-positive cells were localized on the epithelial layers of cystically dilated glands and the down-growing epithelium of nasal polyps. Fas-L may play an important role in the pathogenesis of human nasal polyps, including cystic degeneration of submucosal glands and conferring of immune privilege to nasal polyp formation.

Quantitative glycohistochemical characterization of normal nasal mucosa, and of single as opposed to massive nasal polyps

A series of 41 nasal polyps (23 single and 18 massive) and 6 normal nasal mucosa specimens was glycohistochemically investigated. Five plant lectins were used, i.e., the peanut agglutinin (PNA), the wheat germ agglutinin (WGA), the gorse seed agglutinin (UEA-I), the Maackia amurensis agglutinin (MAA), and the elderberry bark agglutinin (SNA). A neoglycoconjugate and 2 animal lectins (CL-14 and CL-16) were also used. Three quantitative features were calculated by means of computer-assisted microscopy: the percentage of tissue area specifically stained by the histochemical probe, the staining intensity, and the heterogeneity level of the staining distribution. The results show that with respect to sialic acid-glycoprotein binding characteristics as determined by SNA, MAA, and WGA probes, the normal nasal mucosa differed markedly (p<.00001) from the polyposal one. The single nasal polyps exhibited glycohistochemical characteristics that differed markedly (p = .0004) from those exhibited by the massive ones. These differences related mainly to the UEA-I, PNA, and the Thomsen-Friedenreich antigen-exposing neoglycoprotein binding characteristics. In conclusion, the present study shows unambiguously that polyposal mucosa, whether of the single or the massive type, exhibits markedly distinct glycohistochemical characteristics when compared to normal nasal mucosa, and that single nasal polyps also differ markedly from massive ones.

Characterization of the eosinophil chemokine RANTES in nasal polyps

Previous studies have demonstrated that the cytokine RANTES (Regulated And Normal T cell Expressed and Secreted) has been shown to be a potent mediator of eosinophil chemotaxis in vitro and of leukocyte recruitment. Because eosinophils are the hallmark cells in nasal polyposis, we hypothesize that RANTES is locally produced within the nasal polyp microenvironment and is responsible for the eosinophil recruitment seen in nasal polyposis. To begin to test this hypothesis, we evaluated nasal polyps from 17 patients and 3 control specimens for distribution and content of RANTES using immunohistochemical techniques and enzyme-linked immunosorbent assay technology. Our immunohistochemical studies demonstrated that in nasal polyposis, RANTES antigen staining occurred predominantly within eosinophils and epithelial cells. To quantify the relative levels of RANTES in normal and nasal polyp specimens, tissue homogenates were prepared, quantified, and normalized to protein levels. We detected RANTES in all 17 nasal polyp tissue homogenates (566 +/- 16 pg/mg total protein). The RANTES levels in nasal polyp homogenates were nearly 40-fold higher than the RANTES levels in normal tissue (15.7 +/- 28.2 pg/mg total protein). Thus, it appears that increased expression of RANTES by eosinophils and epithelial cells within the nasal polyp microenvironment promotes eosinophil recruitment and activation within nasal polyps. We hypothesize that RANTES induces increased recruitment and activation of eosinophils, presumably contributing to the increased tissue changes associated with nasal polyposis.

Algorithm analysis of lectin glycohistochemistry and Feulgen cytometry for a new classification of nasal polyposis

The aim of this study is to present a new classification of nasal polyps. This classification is based both on morphologic criteria relating to morphonuclear features from isolated Feulgen-stained nuclei and on glycohistochemical characteristics from histologic slides submitted to three lectins (peanut, wheat germ, and gorse seed agglutinins) and one neoglycoconjugate glycohistochemical stain. While the morphonuclear features (including 30 variables) relate essentially to chromatin pattern, the glycohistochemical stains (including 16 variables) are linked to the presence of specific carbohydrate moieties in cell membranes and cytoplasm. Forty-nine nasal polyps, including single polyps, diffuse polyposis, cystic fibrosis-related polyposis, and aspirin idiosyncracy-related polyposis associated with asthma, were thus characterized. All the variables were obtained quantitatively by means of computer-assisted microscopy. Two complementary methods of data classification were used to determine the actual diagnostic value contributed by each quantitative variable, namely, discriminant analysis, which forms part of multifactorial statistical analysis, and the decision tree technique, which is an artificial intelligence-related algorithm. The data so obtained show that our morphologic classification of nasal polyps fits in with the classification of nasal polyps defined on the basis of clinical criteria.

Interleukin-8 Expression in Human Nasal Polyps

The cytokine Interleukin 8 (IL-8) has been shown to be a potent mediator of leukocyte recruitment and neovascularization in inflammatory and neoplastic diseases. In this study we hypothesize that IL-8 produced in the nasal polyp microenvironment is responsible for the leukocyte recruitment seen in nasal polyposis. To test this hypothesis we evaluated nasal polyps for distribution and content of IL-8 antigen with immunohistochemical techniques and radioimmunoassay to determine tissue levels of IL-8. The immunohistochemical results demonstrated that IL-8 antigen staining occurred predominantly within inflammatory cells and epithelium. IL-8 was detected in all nasal polyp tissue homogenates (a mean value of 1767 ± 1633 pg/mg total protein (TP) with a range of 134 to 3668 pg/mg TP vs control specimens with a mean value of 77 pg/mg TP with a range of 0.09 to 255 pg/mg TP). These data demonstrate the presence and distribution and levels of IL-8 antigen in nasal polyps in vivo, supporting our hypothesis that local production of IL-8 could be an important factor in the sustained recruitment of leukocytes in nasal polyposis. Thus IL-8 likely plays a significant role in the pathogenesis of this disease process and therefore is a potential target for therapeutic intervention.