HLA patterns in patients with nasal polyposis

Expression Levels of Glutathione S-Transferase and Cytochrome P450 Isoenzymes in Nasal Polyp Tissue

Nasal polyps are benign sinonasal masses composed of eosinophils and extracellular edema. Pathogenesis of the polyp formation is unclear but several studies strongly suggest a correlation with infection, inflammation and allergy conditions. Our aim is to investigate the potential link between allergy and nasal polyp in tissue level. Nasal polyp group included 60 patients whose diagnosis was confirmed with biopsy and the control group included 38 healthy patients. Tissue sample of the control group was taken from inferior turbinate mucosa under local anesthesia and nasal polyp tissue was collected from functional endoscopic sinus surgery. The glutathione S-transferase (GST) and cytochrome P450 (CYP) isoenzyme expressions of the tissue samples were investigated under light microscopy and graded by a senior pathologist. GSTP1 protein expression was significantly higher in tissue samples from nasal polyp group compared to that of control group (p < 0.05). However, CYP1A1, GSTM1 and GSTA1 isoenzymes were not different between the two groups (p > 0.05). We have found that GSTP1 isoenzyme was elevated in nasal polyp tissue compared to the control. The increase in protein expression of GSTP1 might have occured as a tissue response to the increased oxidative stress thus suggesting a role of GSTP1 in polyp formation.

Genetics and epigenetics of chronic rhinosinusitis

Discerning the genetics and epigenetics of chronic rhinosinusitis (CRS) may optimize outcomes through early diagnostics, personalized and novel therapeutics, and early prognostication. CRS associated with cystic fibrosis and primary ciliary dyskinesia has well-characterized genetic mutations. Most CRS subjects, however, do not exhibit identifiable monogenic alterations. Clustering in related individuals is seen in CRS with nasal polyps. Spouses of subjects with CRS without nasal polyps also may be at increased risk of the same disease. These observations generate questions on genetic and environmental influences in CRS. Genome-wide association studies have identified variations and polymorphisms between CRS and control subjects in genes related to innate and adaptive immunity. Candidate gene and transcriptomics studies have investigated and identified genetic variations related to immunity, inflammation, epithelial barrier function, stress-response, antigen processing, T-cell regulation, and cytokines in CRS. Epigenetic studies have identified mechanisms through which environmental factors may affect these gene functions. However, causality is not determined for most variations. Inferences drawn from these data must be measured because most investigations report unreplicated results from small study populations. Large, replicated studies in tight cohorts across diverse populations remain a pressing need in studying CRS genetics.

An Overview of the Application of Systems Biology in an Understanding of Chronic Rhinosinusitis (CRS) Development

Chronic rhinosinusitis (CRS) is an inflammatory disease of the paranasal sinuses. It is defined as the presence of a minimum of two out of four main symptoms such as hyposmia, facial pain, nasal blockage, and discharge, which last for 8–12 weeks. CRS significantly impairs a patient’s quality of life. It needs special treatment mainly focusing on preventing local infection/inflammation with corticosteroid sprays or improving sinus drainage using nasal saline irrigation. When other treatments fail, endoscopic sinus surgery is considered an effective option. According to the state-of-the-art knowledge of CRS, there is more evidence suggesting that it is more of an inflammatory disease than an infectious one. This condition is also treated as a multifactorial inflammatory disorder as it may be triggered by various factors, such as bacterial or fungal infections, airborne irritants, defects in innate immunity, or the presence of concomitant diseases. Due to the incomplete understanding of the pathological processes of CRS, there is a continuous search for new indicators that are directly related to the pathogenesis of this disease—e.g., in the field of systems biology. The studies adopting systems biology search for possible factors responsible for the disease at genetic, transcriptomic, proteomic, and metabolomic levels. The analyses of the changes in the genome, transcriptome, proteome, and metabolome may reveal the dysfunctional pathways of inflammatory regulation and provide a clear insight into the pathogenesis of this disease. Therefore, in the present paper, we have summarized the state-of-the-art knowledge of the application of systems biology in the pathology and development of CRS.

What is the evidence for genetics in chronic rhinosinusitis?

PURPOSE OF REVIEW

To perform analysis of evidence in current literature on the topic of genetics and chronic rhinosinusitis (CRS), with a particular focus on recent findings in the cystic fibrosis transmembrane regulator (CFTR), genes associated with primary ciliary dyskinesia, and taste receptor T2R38. Other genes that have been found to have association with CRS are also presented and discussed.

RECENT FINDINGS

Recent studies in CFTR and CRS research have investigated possible CFTR-potentiators for treatment of refractory CRS. The T2R38 gene has been shown to be applicable in the clinical setting with a testable phenotype and may have a role in the prognosis and influencing management strategies of CRS patients. Many genes of the immune system have been studied, with genome-wide association studies and candidate-gene approaches identifying new associations that will need replication and further elucidation.

SUMMARY

CRS is a multifactorial disease, with strong evidence of a genetic component in its pathophysiology for some cases. Currently, there are over 70 genes that have been genetically associated with CRS in the past 15 years. Future investigations into genetic causes and predispositions of CRS may allow for improved prognostication and development of disease-prevention strategies as well as novel therapeutic targets.

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

Epidemiology of chronic rhinosinusitis, selected risk factors, comorbidities, and economic burden

Chronic rhinosinusitis (CRS) is a relevant and prevalent medical condition in Germany, Europe and the world. If analysed in detail, the prevalence of CRS shows regional and temporary variety. In this review, currently available data regarding the prevalence of CRS is therefore sorted by country and/or region, time point of data collection and the CRS-definition employed. Risk factors like smoking and gastroesophageal reflux are discussed regarding their influence on CRS prevalence. Moreover, comorbidities of CRS, like asthma, conditions of the cardiovascular system and depression are listed and their influence on CRS is discussed. Furthermore, data on CRS prevalence in special cohorts, like immunocompromised patients, are presented. To estimate the economic burden of CRS, current data e.g. from Germany and the USA are included in this review.

Risk factors for chronic rhinosinusitis

PURPOSE OF REVIEW

To review the recent literature on risk factors for chronic rhinosinusitis (CRS) with an emphasis on genetic, comorbid diseases and environmental factors associated with CRS. Through identifying potential risk factors for CRS, we aim to glean insights into the underlying pathogenic mechanisms essential for developing effective therapeutic strategies.

RECENT FINDINGS

Recent findings demonstrate that genetics and comorbid medical conditions including airway diseases, gastroesophageal reflux disease, inflammatory and autoimmune diseases, and various demographic and environmental factors are associated with having a CRS diagnosis. Limitations of current studies include variable application of disease definitions, lack of prospective longitudinal studies and a disproportionate focus on tertiary care populations.

SUMMARY

CRS has a broad spectrum of associations ranging from genetics to comorbid diseases and environmental factors. These predisposing factors may provide valuable information for possible designing of therapeutic and preventive interventions. However, to better understand whether these associations cause CRS, further studies are needed to independently replicate findings, establish temporal relationships between exposure and disease onset, evaluate the influence of exposure dose on disease severity, and to understand the biological effects of these risk factors in the context of CRS.

Analysis of Il-10 gene sequence in patients with sinonasal polyposis

Sinonasal polyposis (SNP) is a chronic inflammatory disease of nasal and paranasal cavities. Human leukocyte antigen-G molecules (HLA-G) are non-classic HLA-I molecules with anti-inflammatory and tolerogenic properties. HLA-G production is mainly induced by interleukin (IL)-10. IL-10 is an anti-inflammatory cytokine that inhibits the production of proinflammatory cytokines and induces HLA-class II down-modulation. Recent studies suggest that HLA-G could play a role in SNP pathogenesis; in SNP patients physiological levels of IL-10 (produced by activated peripheral blood CD14+ monocytes) are not able to induce production of HLA-G. Different mechanisms could justify these findings: genomic or amino-acidic sequence alterations in IL-10 lower IL-10 receptor expression, lower IL-10 receptor affinity, or alterations of the intracellular signal transmission. This study analyzes nucleotidic sequence of IL-10 gene in SNP patients. Sequencing of IL-10 gene shows that the lack of HLA-G production by peripheral blood CD14+ monocytes is not related to alterations in IL-10 gene nucleotidic sequence.

ICON: chronic rhinosinusitis

Chronic rhinosinusitis (CRS) is a public health problem that has a significant socio-economic impact. Moreover, the complexity of this disease due to its heterogeneous nature based on the underlying pathophysiology - leading to different disease variants - further complicates our understanding and directions for the most appropriate targeted treatment strategies. Several International/national guidelines/position papers and/or consensus documents are available that present the current knowledge and treatment strategies for CRS. Yet there are many challenges to the management of CRS especially in the case of the more severe and refractory forms of disease. Therefore, the International Collaboration in Asthma, Allergy and Immunology (iCAALL), a collaboration between EAACI, AAAAI, ACAAI, and WAO, has decided to propose an International Consensus (ICON) on Chronic Rhinosinusitis. The purpose of this ICON on CRS is to highlight the key common messages from the existing guidelines, the differences in recommendations as well as the gaps in our current knowledge of CRS, thus providing a concise reference. In this document we discuss the definition of the disease, its relevance, pharmacoeconomics, pathophysiology, phenotypes and endotypes, genetics and risk factors, natural history and co-morbidities as well as clinical manifestations and treatment options in both adults and children comprising pharmacotherapy, surgical interventions and more recent biological approaches. Finally, we have also highlighted the unmet needs that wait to be addressed through future research.

Genetics of chronic rhinosinusitis: state of the field and directions forward

The cause of chronic rhinosinusitis (CRS) remains unclear. Study of the genetic susceptibility to CRS might be a valuable strategy to understand the pathogenesis of this burdensome disorder. The purpose of this review is to critically evaluate the current literature regarding the genetics of CRS in a comprehensive fashion. The most promising findings from candidate gene studies include the cystic fibrosis transmembrane conductance regulator gene (CFTR), as well as genes involved in antigen presentation, innate and adaptive immune responses, tissue remodeling, and arachidonic acid metabolism. We also review the few hypothesis-independent genetic studies of CRS (ie, linkage analysis and pooling-based genome-wide association studies). Interpretation of the current literature is limited by challenges with study design, sparse replication, few functional correlates of associated polymorphisms, and inadequate examination of linkage disequilibrium or expression quantitative trait loci for reported associations. Given the relationship of CRS to other airway disorders with well-characterized genetic components (eg, asthma), study of the genetics of CRS deserves increased attention and investment, including the organization of large, detailed, and collaborative studies to advance knowledge of the mechanisms that underlie this disorder.

HLA-DRA polymorphisms associated with risk of nasal polyposis in asthmatic patients

BACKGROUND

Nasal polyps, part of the aspirin triad symptoms, are edematous protrusions arising from the mucosa of the nasal sinuses. Although the causative factors and pathogenesis of the polyps are unknown, the significant effect of human leukocyte antigen-DR (HLA-DR) expression in nasal polyps and genetic associations of the major histocompatibility complex class II, DR alpha (HLA-DRA) with immune-mediated diseases have been revealed.

METHODS

To investigate the associations of HLA-DRA polymorphisms with nasal polyposis in asthmatic patients and in aspirin-hypersensitive subgroups, 22 single nucleotide polymorphisms (SNPs) were genotyped in a total of 467 asthmatic patients including 158 nasal polyp-positive and 309 polyp-negative subjects.

RESULTS

Statistical analysis showed that four SNPs (p = 0.0005-0.02; Pcorr = 0.009-0.033) and one haplotype (p = 0.002; Pcorr = 0.029) were significantly associated with the presence of nasal polyposis in asthmatic patients. In further analysis, although significant signals disappeared after corrections for multiple testing, two HLA-DRA polymorphisms (rs9268644C>A, rs3129878A>C) were found to be potential markers for nasal polyp development in aspirin-tolerant asthma (p = 0.005 and 0.007, respectively) compared with the aspirin-exacerbated respiratory disease (p > 0.05) subgroup. In silico analysis predicted major "C" allele of rs14004C>A in 5'-untranslated region as a potential binding site for regulatory glucocorticoid receptor. In addition, sequence nearby rs1051336G>A is suspected to be a pyrimidine-rich element that affects mRNA stability.

CONCLUSION

Despite the need for replication in larger cohorts and/or functional evaluations, our findings suggest that HLA-DRA polymorphisms might contribute to nasal polyposis susceptibility in patients with asthma.

Memory T cells in the chronic inflammatory microenvironment of nasal polyposis are hyporesponsive to signaling through the T cell receptor

A majority of T cells from chronic inflammatory tissues derived from patients with nasal polyposis were found to express an effector memory phenotype. We report here that these memory T cells failed to activate NF-κB in response to TCR stimulation but responded normally when the proximal TCR signaling molecules were bypassed with PMA and ionomycin. The dysfunction of these cells was associated with a decrease in the phosphorylation of several TCR proximal signaling molecules including ZAP70, Lck and SLP-76. In addition to the disruption in the TCR signaling pathway, the nasal polyp-associated T cells were shown to have a defect in their ability to translocate LAMP-1 to the cell surface. The results presented here establish that the phenotype and anergy of the T cells in the nasal polyp are similar to those which is seen in memory T cells derived from human tumors and other sites of chronic inflammation.

Does mannose-binding lectin have a role in adult Turkish patients with nasal polyposis?

OBJECTIVE

Mannose-binding lectin is an important component of innate immunity; it initiates the lectin pathway of complement activation critical for innate immunity. Failure of local innate defenses may result in defective responses that lead to the persistent carriage of microorganisms or ongoing inflammation. This study investigated the role of mannose-binding lectin levels and the frequency of the 6 functional mannose-binding lectin polymorphisms in Turkish individuals with nasal polyposis.

STUDY DESIGN

A case-control study.

SETTING

University hospital.

SUBJECTS AND METHODS

Fifty-one patients with nasal polyposis and 53 healthy controls were enrolled. Serum mannose-binding lectin levels were obtained by enzyme-linked immunosorbent assay (ELISA) using the mannose-binding lectin oligomer ELISA kit. Mannose-binding lectin 2 genotyping was performed by isolating the genomic DNA from leukocytes.

RESULTS

Mean mannose-binding lectin levels were 1693.2 and 1887.8 in the patient and control group, respectively. Although mannose-binding lectin levels were lower in the patient group, the difference was not statistically significant (P > .05). No overall association was observed between the mannose-binding lectin genotype and susceptibility to nasal polyposis (95% confidence interval = 0.716-4.389, odds ratio = 1.773). The mutant allele frequencies of the 3 structural polymorphisms did not differ significantly between the nasal polyposis patients and the controls (P = .659).

CONCLUSIONS

Mannose-binding lectins are not involved in the pathogenesis of nasal polyposis in adult Turkish patients, but additional research is needed for further comment.

The glutathione-S-transferase gene polymorphisms (Gstt1, Gstm1, and Gstp1) in patients with non-allergic nasal polyposis

There is an ongoing dilemma about the pathogenesis of nasal polyp (NP). The etiology of NP is multifactorial. Reactive oxygen species and oxidative stress are also suggested to be among the possible factors in NP development. Glutathione-S-transferase (GST) is one of the important detoxifying enzymes. It is not known whether GST plays any role in NP development. We aimed to investigate the relationship between GST subgroup (GSTT1, GSTM1, and GSTP1) polymorphisms, and NP development. Seventy-five patients with NP with or without asthma (NP with asthma: 22, NP without asthma: 53) were used as a study group. As much as 167 healthy individuals were involved as the control group. NP diagnosis was made by nasal endoscopy and paranasal sinus computed tomography (CT). NP was defined as the presence of endoscopically visible bilateral polyps originated from the middle meatus to the nasal cavity and affecting more than one paranasal sinus confirmed by CT. Blood was collected in EDTA-containing tubes and DNA was extracted from the leukocytes. The genotyping of polymorphisms of GSTT1, GSTM1, and GSTP1 were done using real time polymerase chain reaction. Chi-square (chi(2)) and Fisher's (F) exact tests were used for statistical evaluation. A 2-fold increased risk of NP could be found in individuals with the GSTT1 null genotype (OR = 2.03, 95% CI = 1.03-4.011). The distribution of GSTM1 null genotypes was not significantly different between the NP patients and controls and there was also no significance between the GSTP1 genotypes and NP. In conclusion, GST gene polymorphisms may be important in pathogenesis of NP. Additional studies which include larger study groups in different geographic localizations may be more useful to evaluate association with GST polymorphism and NP.

Identification of susceptibility genes for complex diseases using pooling-based genome-wide association scans

The success of genome-wide association studies (GWAS) to identify risk loci of complex diseases is now well-established. One persistent major hurdle is the cost of those studies, which make them beyond the reach of most research groups. Performing GWAS on pools of DNA samples may be an effective strategy to reduce the costs of these studies. In this study, we performed pooling-based GWAS with more than 550,000 SNPs in two case-control cohorts consisting of patients with Type II diabetes (T2DM) and with chronic rhinosinusitis (CRS). In the T2DM study, the results of the pooling experiment were compared to individual genotypes obtained from a previously published GWAS. TCF7L2 and HHEX SNPs associated with T2DM by the traditional GWAS were among the top ranked SNPs in the pooling experiment. This dataset was also used to refine the best strategy to correctly identify SNPs that will remain significant based on individual genotyping. In the CRS study, the top hits from the pooling-based GWAS located within ten kilobases of known genes were validated by individual genotyping of 1,536 SNPs. Forty-one percent (598 out of the 1,457 SNPs that passed quality control) were associated with CRS at a nominal P value of 0.05, confirming the potential of pooling-based GWAS to identify SNPs that differ in allele frequencies between two groups of subjects. Overall, our results demonstrate that a pooling experiment on high-density genotyping arrays can accurately determine the minor allelic frequency as compared to individual genotyping and produce a list of top ranked SNPs that captures genuine allelic differences between a group of cases and controls. The low cost associated with a pooling-based GWAS clearly justifies its use in screening for genetic determinants of complex diseases.

Significance of susceptible gene expression profiles in nasal polyposis

Nasal polyposis (NP) is a common chronic inflammatory disease of the rhinosinus mucosa and a complex disease with strong genetic and environmental components. During the past 10 to 20 yr, many studies have been performed to determine differential gene expression profiles between NP and normal nasal tissues, in order to identify susceptible genes that are associated with NP-related traits. Despite achievement in the identification of candidate genes and their associated pathogenic pathways, the large challenges remain as the genetic and molecular alterations required for its development and progression are still unclear. Therefore, the development of novel, powerful tools for gene discovery, and a closer integration of genetics and medical biology would provide valuable insight into the pathogenesis of NP.

Evaluation of HLA-A, -B, -Cw, and -DRB1 alleles frequency in Turkish patients with nasal polyposis

OBJECTIVE

To evaluate whether there is a relationship between HLA-A, -B, -Cw, and -DRB1 alleles and developing nasal polyposis (NP).

STUDY DESIGN

Data from 66 patients with NP were compared with data from 100 healthy randomly selected controls. Asthma, ASA (acetylsalicylic acid) triad, polyp score, and previous sinonasal surgery were also recorded.

SUBJECTS AND METHODS

Genotyping of the HLA-A, -B, -Cw, and -DRB1 alleles were performed with polymerase chain reaction (PCR) with the sequence-specific primer (SSP) method. Data were analyzed by using a Pearson chi(2) test.

RESULTS

The HLA-B*07 and -Cw*12 alleles were found to be significantly higher in the NP patients compared with the control group, whereas the HLA-B*57 and HLA-Cw*04 alleles were significantly lower (P < 0.05). The HLA-A*24, HLA-Cw*12, and HLA-DRB1*04 alleles were determined to be significantly higher in the NP patients with asthma and ASA triad (P < 0.05).

CONCLUSIONS

Our results show that some of the HLA alleles seem to be associated with the genetic susceptibility to develop NP in the Turkish population.

Decreased production of human leukocyte antigen G molecules in sinonasal polyposis

BACKGROUND

Sinonasal polyposis (SNP) is a chronic inflammatory pathology of nasal and paranasal cavities. Human leukocyte antigen (HLA) G molecules are nonclassic class I antigens with anti-inflammatory and tolerogenic properties. As most theories consider polyps to be the manifestation of chronic inflammation, there could be a possible implication of HLA-G molecules in SNP. The purpose of this study was to investigate the possible correlation between SNP and the production of soluble HLA-G (sHLA-G) by peripheral blood mononuclear cells (PBMCs).

METHODS

The study involved 22 SNP patients (11 with no evidence of disease [NED] after surgery and 11 with relapse [RE]) and 20 healthy subjects. The presence of sHLA-G in PBMC lipopolysaccharide (LPS)-stimulated culture supernatants was analyzed. The levels of interleukin (IL) 10, one of the main up-regulators of sHLA-G production, were determined. Exogenous IL-10 was added to the SNP PBMC cultures to reconstitute the impairment in sHLA-G production.

RESULTS

Increased IL-10 levels in LPS-activated PBMC culture supernatants were found in NED patients in comparison with healthy subjects (p = 0.0184). No sHLA-G production was observed in either of the patient subgroup supernatants (p < 0.0001). The addition of exogenous IL-10 showed the reconstitution of sHLA-G production in NED and in a lower amount in RE patients.

CONCLUSION

The results show a defect in sHLA-G production in SNP patients mainly related to the IL-10/HLA-G pathway. Given the anti-inflammatory functions of HLA-G molecules, this impairment could increase the susceptibility to the disease. The different sHLA-G production after exogenous IL-10 addition between NED and RE SNP could represent a marker of disease severity.

[Diversity of nasal polyps in microarray technology research]

Nasal polyps, according to many authors, generate as a result of chronic inflammation process with activation of cytokines, immunological reaction mediators that regulate proliferation, differentiation and cell apoptosis. Clarifying molecular mechanisms present in those disturbances may have diagnostic and prognostic value in evaluation of recurrence, dynamics and differentiation of nasal polyps as well as in their therapy.

AIM

The aim of the work was an analysis of nasal polyps on the basis of molecular, histopathological and clinical picture as well as comparing differentiated genes transcription in nasal polyps and proper nasal mucosa.

MATERIAL AND METHOD

Oligonucleotide array with HGU 133A - Affymetrix were used to analyze the expression of 22,283 genes in nasal polyp tissues from 17 patients. The control group consisted of 8 tissue samples from patients after nasal septoplasty surgery.

RESULTS

All the samples could be classified to nasal polyps group or proper mucosa group, it reflected significant differences in genes profile expression in both groups. The evaluation of 22,283 genes transcriptions showed that in most cases nasal polyps tissue reflect classification connected with dominant inflammation cells infiltration. The data obtained let distinguish subgroups connected with clinical condition of the patients. The subgroup with massive nasal and sinus polyposis, eosinophilia and differentiated lower respiratory airways hyperactivity and the subgroup without eosinophilia infiltration may be distinguished. The data obtained suggest that molecular mechanisms may influence on the promotion and kind of inflammation process as well as the clinical course of nasal polyps.

A review of nasal polyposis

Nasal polyps are common, affecting up to four percent of the population. Their etiology remains unclear, but they are known to have associations with allergy, asthma, infection, cystic fibrosis, and aspirin sensitivity. They present with nasal obstruction, anosmia, rhinorrhoea, post nasal drip, and less commonly facial pain. Clinical examination reveals single or multiple grey polypoid masses in the nasal cavity. Computerized tomography allows evaluation of the extent of the disease and is essential if surgical treatment is to be considered. Management of polyposis involves a combination of medical therapy and surgery. There is good evidence for the use of corticosteroids (systemic and topical) both as primary treatment and as postoperative prophylaxis against recurrence. Surgical treatment has been refined significantly over the past twenty years with the advent of endoscopic sinus surgery and, in general, is reserved for cases refractory to medical treatment. Recurrence of the polyposis is common with severe disease recurring in up to ten percent of patients.

Influence of leukotriene gene polymorphisms on chronic rhinosinusitis

BACKGROUND

Chronic rhinosinusitis (CRS) is increasingly viewed as an inflammatory condition of the sinonasal mucosa interacting with bacteria and/or fungi. However, factors conferring susceptibility to disease remain unknown. Advances in genomics offer powerful tools to explore this disorder. The goal of this study was to evaluate the effect of single nucleotide polymorphisms (SNP) on CRS in a panel of genes related to cysteinyl leukotriene metabolism.

METHODS

Severe cases of CRS and postal code match controls were recruited prospectively. A total of 206 cases and 200 controls were available for the present study. Using a candidate gene approach, five genes related to cysteinyl leukotriene metabolism were assessed. For each gene, we selected the maximally informative set of common SNPs (tagSNPs) using the European-derived (CEU) HapMap dataset. These SNPs are in arachidonate 5-lipoxygenase (ALOX5), arachidonate 5-lipoxygenase-activating protein (ALOX5AP), leukotriene C4 synthase (LTC4S), cysteinyl leukotriene receptor 1 (CYSLTR1) and cysteinyl leukotriene receptor 2 (CYSLTR2) genes.

RESULTS

A total of 59 SNPs were genotyped to capture the common genetic variations within these genes. Three SNPs located within the ALOX5, CYSLTR1 and ALOX5AP genes reached the nominal p-value threshold (p < 0.05) for association with CRS. However, none of these SNPs resist multiple testing adjustment.

CONCLUSION

While these initial results do not support that polymorphsims in genes assessed involved in the leukotriene pathways are contributing to the pathogenesis of CRS, this initial study was not powered to detect polymorphisms with relative risk of 2.0 or less, where we could expect many gene effects for complex diseases to occur. Thus, despite this lack of significant association noted in this study, we believe that validation with external populations and the use of better-powered studies in the future may allow more conclusive findings.

Pathogenesis of chronic rhinosinusitis

Chronic rhinosinusitis (CRS) is a heterogenous disorder and represents a major public health problem. Although insights into the pathophysiology of CRS have largely expanded over the last two decades, the exact etiology and mechanism of persistence is still unrevealed. CRS is a multifactorial disease, and, with variable evidence, impaired ostial patency, mucociliary impairment, allergy, bacterial or fungal infection (or triggering), immunocompromised state, and environmental and genetic factors have been suggested to be associated or risk factors. Pathomechanisms in CRS are better understood currently, allowing us to characterize and differentiate the heterogeneous pathology of chronic sinonasal inflammation based on histopathology, inflammatory pattern, cytokine profile, and remodeling processes. In nasal polyposis (NP), but not CRS without NP, an abundant eosinophilic inflammation and local immunoglobulin E production could be demonstrated, and Staphylococcus-derived superantigens may at least modulate disease severity and expression. These findings question the current assumption that NP is a subgroup of CRS, but suggest that CRS and NP should probably be considered as distinct disease entities.

DQA1 and DQB1 association and nasal polyposis

OBJECTIVE

The aim of this study was to determine the contribution of the human major histocompatibility complex (HLA)-DQA1, -DQB1, and TNFalpha genes with simple nasal polyposis.

STUDY DESIGN AND SETTING

A comparative case-control study with 31 patients and 151 controls was performed. HLA-DQA1, -DQB1, and TNFalpha -238 promoter position loci were typed by polymerase chain reaction (PCR) and sequence specific oligonucleotide probes (SSOPs). TNFalpha -308 promoter position was determined by PCR and digestion with NcoI restriction enzyme.

RESULTS

The allele HLA-DQA1*0201 (P(c) = 0.019) had an etiologic fraction (EF) of 17%, whereas 13% EF was found for the haplotype HLA-DQA1*0201-DQB1*0201 (P = 0.016). Analysis of -DQB1 and TNFalpha promoter did not show significant differences between cases and controls.

CONCLUSIONS

HLA-DQA1*0201-DQB1*0201 haplotype is involved in susceptibility, conferring 5.53 times more risk of developing this disease.

EBM RATING

B-2b.

Pathogenesis of nasal polyps: an update

The cause of nasal polyp formation is still unknown. Genetic predisposition has been suggested, but there are scanty data to support such theories. Activated epithelial cells may be the major source of mediators inducing influx of inflammatory cells (mostly eosinophils) and proliferation and activation of fibroblasts leading to nasal polyp formation. Infectious agents (including viruses, bacteria, or fungi) may be potential primary factors activating nasal epithelial cells. Proinflammatory cytokines and growth factors play important roles in the persistence of mucosal inflammation associated with nasal polyps. Arachidonic acid metabolites seem to be particularly important in the pathogenesis of nasal polyps in patients with aspirin hypersensitivity rhinosinusitis/asthma syndrome.

Analysis of most common CFTR mutations in patients affected by nasal polyps

Nasal polyps, a chronic inflammatory disease occurring in the nose and para-nasal sinuses, result from several different causes, including cystic fibrosis (CF). Forty-four patients affected by nasal polyps were admitted to the Department of Otolaryngology, Lublin University School of Medicine, Lublin, Poland, and screened for the most-commonly identified CFTR mutations [DeltaF508, G542X, N1303 K, 1717-1 (G to A), W1282X, G551D, R553X and DeltaI507] by applying the INNO-LIPA CF2 test strips. None of the patients had symptoms that allowed for the diagnosis of CF, including the negative sweat test. We detected 5 of 44 (11.4%) carriers of the CFTR mutations. All patients positive for this test were heterozygous carriers of DeltaF508. In the control group, only 1 of 70 (1.4%) cases showed DeltaF508 heterozygosity. The frequency of DeltaF508 mutation herein reported was significantly higher than in the control group (P = 0.0312) and in the general Polish population as well (P = 0.0059). Our data suggest that a heterozygous manifestation of the DeltaF508 may exist in a selected group of patients affected by nasal polyps, who have no other clinical features of CF.

HLA-DQB1 *03 in allergic fungal sinusitis and other chronic hypertrophic rhinosinusitis disorders

BACKGROUND

Many common chronic inflammatory disorders have strong HLA gene associations, particularly with MHC class II. Allergic fungal rhinosinusitis (AFS) and hypertrophic sinus disease (HSD) are chronic sinonasal mucosal inflammatory disorders. Allergic bronchopulmonary aspergillosis, a disorder analogous to AFS, was recently reported to have HLA-MHC class II associations.

OBJECTIVE

We sought to determine whether MHC class II is also associated with AFS and HSD.

METHODS

HLA DNA genotyping was obtained on 44 patients with AFS and 30 patients with HSD (of which 21 were atopic).

RESULTS

Sixty-six percent of patients with AFS carried at least one HLA-DQB1 *03 allele; DQB1 *0301 and DQB1 *0302 were the most frequent allelic variants (odds ratio [OR] vs healthy subjects = 8.22; 95% CI, 4.30-15.73; P < .001; OR vs all patients with HSD = 1.93; 95% CI, 1.09-3.41; P < .01; OR vs atopic patients with HSD = 2.57; 95% CI, 1.46-4.53; P < .001). Of the 31 patients with AFS and positive Bipolaris spicifera cultures, 68% had DQB1 *03, with DQB1 *0301 and DQB1 *0302 being most frequent (OR vs healthy subjects = 8.93; 95% CI, 4.65-17.15; P < .001; OR vs patients with HSD = 2.10; 95% CI, 1.18-3.73; P < .001). Of the 30 patients with HSD, 50% carried DQB1 *03 (OR vs healthy subjects = 4.25; 95% CI, 2.25-8.02; P < .001) but differed in frequencies of DQB1 *03 allelic variants compared with patients with AFS ( P = .0004). For HSD, nonatopic subjects had the highest DQB1 *03 association (OR vs healthy subjects = 8.63; 95% CI, 4.50-16.54; P < .001). DQB1 *03 allelic variants did not correlate with allergy skin test results, atopic status, total serum IgE levels, culture results, asthma, or aspirin-nonsteroidal anti-inflammatory drug hypersensitivity.

CONCLUSION

Patients with AFS and HSD have HLA-DQB1 *03 alleles as a risk factor for disease, with AFS having the highest association. However, they differ in DQB1 *03 allelic variant frequencies, suggesting several potential roles for MHC class II in their immunopathogenesis.

Antrochoanal polyp: a transmission electron and light microscopic study

Antrochoanal polyp (ACP) is a soft tissue mass originating from the maxillary antrum, emerging from the ostium and extending to the choana through the nasal cavity. Our aim was to investigate the light microscopic and ultrastructural features of ACP and to compare these with nasal polyps originating from the middle meatus (MMP). Seven ACP and seven MMP specimens were evaluated by transmission electron microscopy (TEM) and light microscopy. TEM examination showed epithelial cells with intact cilia covering both polyps. In some MMP cases, degeneration of the epithelium associated with some cilia loss was noted. Goblet cell hyperplasia was more prominent in MMP cases. Degeneration and partial destruction of the endothelial cells of the blood vessels were common findings in ACP cases; however, in the MMP group, endothelial cells were mostly intact with a few aggregates of ribosomes, and intact cell junctions were noted. Light microscopic examination revealed that inflammatory cells in the ACP group were numerous. However, eosinophils were predominant in MMP cases. Squamous metaplasia of the surface epithelium was detected in five ACP cases, but in none of the MMP cases. Basement membrane thickening was detected in two cases of the ACP and in four cases of the MMP group. There was a statistically significant difference between the two groups for inflammatory cells, eosinophilic cell infiltration, squamous cell metaplasia, endothelial cell destruction and goblet cell metaplasia. In conclusion, the low number of eosinophils, the high number of other inflammatory cells, the normal appearing basement membrane and intact and normal surface epithelium may reveal that the etiology of ACP might arise from chronic inflammatory processes rather than allergy. The destruction of the endothelium may be considered as a further sign of chronic inflammation.

Nasal mucosal gene expression in patients with allergic rhinitis with and without nasal polyps

BACKGROUND

Nasal polyps are a common problem that is difficult to diagnose and treat, in part because the cause of nasal polyposis is unknown. Although information on the pathogenesis of polyposis is lacking, there are reports suggesting that a genetic predisposition underlies this disorder.

OBJECTIVE

We sought to better understand the basis of nasal polyposis associated with allergic rhinitis. We hypothesize that the expression of unique genes is associated with the nasal polyposis phenotype.

METHODS

We examined 12000 human genes transcribed in the nasal mucosa of patients with allergic rhinitis with and without nasal polyps. Biopsy specimens of the mucosa of patients with and without polyps were obtained after the patients refrained from the use of topical or systemic steroid therapy for 2 weeks.

RESULTS

Thirty-four genes were differentially expressed between the patient groups, including those for inflammatory molecules and putative growth factors. The greatest differential expression identified by the array analysis was for a group of genes associated with neoplasia, including mammaglobin, a gene transcribed 12-fold higher in patients with polyps compared with control patients with rhinitis alone. Quantitative RT-PCR confirmed this differential expression and documented that the number of mammaglobin mRNA copies is actually 64-fold greater in tissues of patients with polyps versus control patients. The specificity of mammaglobin protein expression was evaluated by means of immunohistochemistry, which showed specific staining in nasal polyp mucosal goblet cells only in patients with polyps.

CONCLUSION

These data suggest that nasal polyposis involves deregulated cell growth, using gene activation in some ways similar to a neoplasm. In addition, mammaglobin, a gene of unknown function associated with breast neoplasia, might be related to polyp growth.