aspirin - exacerbated respiratory disease ( aerd ) is a syndrome characterized by chronic hyperplastic rhinosinusitis , nasal polyposis , asthma , and aspirin sensitivity , as described in 1922 by szczeklik et al . [ 1 , 2 ] . the prevalence of aerd is variable ; stevenson and szczeklik reported in 2006 that aerd occurs in 3% of adult patients with asthma in the united states , with the onset of symptoms during the third decade of life , and that it is more common in women than in men , with approximately 70% versus 30% in europe   and 57% versus 43% in the usa . the mechanisms underlying aspirin intolerance are not fully defined , with current research focusing on cyclooxygenase 1 ( cox-1 ) inhibition by aspirin and other nsaids diverting arachidonic acid metabolism from cox pathways to the lipoxygenase ( lo ) pathway . this leads to increased synthesis of the cysteinyl - leukotrienes ( lt ) , ltc4 , ltd4 , and lte4 , resulting in bronchoconstriction , mucus hypersecretion , and possibly the development of polyps and urticaria . the biological plausibility of this hypothesis fact has led to the search for polymorphisms in genes responsible for lt synthesis , to explore associations between these polymorphisms and local tissue levels of the proteins . other factors such as polymorphisms in the genes for proinflammatory cytokines including tnf , il1b , il6 , and il8 are involved in chronic inflammatory and autoimmune diseases . interleukin 1 ( il-1 ) is a cytokine associated with inflammatory responses and found in two forms , il-1 ( produced by the il1a gene ) and il-1 ( il1b ) , with both genes located on chromosome 2 . il-1 is expressed in nasal polyps , nasal epithelium , macrophages , activated t lymphocytes , and monocytes ; its expression is regulated by adhesion molecules , and others inflammatory cytokines . il1b polymorphisms have been associated with inflammatory bowel disease and gastric cancer among other diseases . recently , genetic polymorphisms in proinflammatory cytokines such as il-1 have been recognized as key players in the pathogenesis of asthma . similarly , il-8 has been implicated in the asthmatic inflammatory process , and genetic variation in this cytokine has been associated with both the susceptibility and the severity of this disease . in the present study , we have investigated the frequencies of polymorphisms in the genes encoding these two cytokines in aerd patients . patients with aspirin - exacerbated respiratory disease ( aerd ) ( n = 78 ) and aspirin - tolerant asthma ( ata ) ( n = 135 ) were recruited from the allergy and otolaryngology departments at the instituto nacional de enfermedades respiratorias ( iner ) . healthy control subjects ( hcs ) all participants underwent simple spirometry , inhaled methacholine challenge , and nasal challenge with lysine - aspirin ( l - asa ) according to international guidelines to determine the degree of bronchial hyperresponsiveness and confirm aerd diagnosis . the aerd group had positive l - asa and methacholine challenges , the asthmatic group had positive methacholine challenge , but negative l - asa challenge , and the healthy control subjects were volunteers with negative l - asa and methacholine challenges . a positive l - asa challenge was defined as a decrease of at least 40% in total nasal airflow after l - asa application compared with baseline measures ; methacholine challenge was considered positive with a decrease of at least 20% in forced expiratory volume in one second ( fev1 ) compared with baseline fev1 after the administration of different concentrations of methacholine ( beginning with 0.03  mg / ml , increasing gradually the concentration twice every 2 minutes until the concentration of 32  mg / ml ) ; in case it does not have it , it is considered negative . the study was approved by the science and bioethics committees of iner , and all participants gave their informed consent [ 8 , 9 ] . patients and healthy control subjects had ancestry of at least two generations born in mexico and were thus considered to be mexican mestizo in descent [ 10 , 11 ] . peripheral blood was drawn by venipuncture , and genomic dna was obtained using the commercial bdtract dna isolation kit ( maxim biotech , san francisco , calif , usa ) . the dna was quantified by absorption of ultraviolet light at 260  nm wavelength using an actgene spectrophotometer ( actgene , inc . we selected two polymorphisms in two genes related to chronic inflammation : rs16944 in il1b and rs4073 in il8 . allelic discrimination of snps rs16944 ( il1b ) and rs4073 ( il8 ) was performed by real - time pcr ( rt - pcr ) on a 7300 real time pcr system ( applied biosystems , calif , usa ) using taqman commercial probes ( applied biosystems , usa ) for each of the polymorphisms mentioned above and followed the cycling program : preread 50c , 1 minute ; absolute quantitation : 50c , 2 minutes , 1 cycle ; 95c , 10 minutes , 1 cycle ; 95c , 15 seconds , 60c 1  min , 40 cycles ; postread 50c , 1 minute . the results were assessed taking into account the allelic discrimination and absolute quantitation in all samples ; additionally , we included four contamination controls per plate ( nontemplate controls ) . the fluorescence signal detectors used were vic which was assigned to the b allele and fam assigned to the a allele for both snps . statistical analysis was performed between groups of cases ( aerd and ata ) versus the healthy control subjects by  test with 3  2 tables , using spss ( v. 15.0 ) software for windows , to identify the difference between the allele and genotype frequencies of each polymorphism evaluated . in addition , odds ratios and 95% confidence intervals were calculated with epi - info ( v. 6.04 ) software . we performed a genetic association study of the il8 ( rs4073 ) and il1b ( rs16944 ) gene polymorphisms in the three groups . genetic data for the snps included in this study are shown in table 1 ; minor allele frequency ( maf ) of the polymorphisms tested in healthy control subjects had a similar distribution to that reported in international databases ( table 1 ) . gene frequencies for each genotype within the three subject groups are shown in table 3 . the frequency of genotypes aa , at , and tt of the il8 rs4073 snp was not statistically significant and different between the three studied groups . analysis of gg and ga genotypes of the il1b ( rs16944 ) snp for aerd and ata patients versus the healthy control subjects showed nonstatistically significant associations . interestingly , the aa genotype showed increased frequency in the aerd patients when compared to the ata group ( gf = 0.19 versus 0.07 ) ; this association was statistically significant ( p = 0.018 , or 2.98 , and ci 1.177.82 ) ( tables 3 and 4 ) and was not found when aerd or ata groups were compared to healthy control subjects . there is no difference in aa versus ag + gg using contrast of healthy control subjects versus aerd patients ( data not shown ) . the airways of aspirin - sensitive patients are characterized by chronic inflammation with cell infiltration even when they are not exposed to aspirin or other nsaids . in addition to alterations in the metabolism of arachidonic acid , several proinflammatory cytokines have been associated with aerd . the role of il-1 , however , has not been investigated previously . here , we report that aerd patients show an increased frequency of the il1b-511 polymorphism ( rs16944 aa genotype ) compared to aspirin - tolerant asthmatics . interleukin-1 has been reported to be involved in the genesis of both asthma [ 13 , 14 ] and chronic rhinosinusitis with nasal polyposis in a turkish population . most studies have attempted to establish the association of polymorphisms in the il1b promoter gene , mainly at positions-511 g / a ( rs16944 ) and -31 c / t . for example , park et al . , in 2004 , did not find any association between these polymorphisms and either asthma or atopy in a korean population . in 2007 , erbek et al . described a susceptibility for developing nasal polyps associated with the il1b-511 polymorphism ( rs16944 ) , but mfuna endam et al . , in 2010 , failed to reproduce this finding in canadian patients with chronic rhinosinusitis . in 2003 , allen et al . did not find any association with il1 gene polymorphisms in asthmatic families ( n = 244 ) , but they reported an association with the dna microsatellite d2s308 in these asthma families ( p = 0.00001 ) . in parallel , karajalein et al . evaluated 245 patients with asthma and nasal polyposis and did not find any association between the polymorphism il1b-511 c / t and nasal polyps . evidence for the role of il-1 in pulmonary immune responses has been gathered in murine models of allergic asthma using il-1r1-deficient [ il-1r1 ( / ) ] mice ; changes observed in these mice include significant reduction of pulmonary eosinophilic inflammation , diminished goblet cell hyperplasia , and reduction of cell recruitment to the lungs , as compared to control balb / c mice . however , there are no studies linking gene promoter polymorphisms and levels of expression of the cytokine in the lung microenvironment . in the present study , we have demonstrated that the frequency of the il1b-511 polymorphism ( rs16944 aa genotype ) is three - fold higher in aerd ( 19.2% ) than in ata patients ( 7.4% ) , suggesting that patients carrying this polymorphism may exhibit genetic susceptibility to develop aerd . findings on the biological functionality of the rs16944 polymorphism have not been consistent across studies . the aa genotype has been associated with higher gastric mucosal levels of il-1 in bacterial infections , while mononuclear cells from subjects with the gg genotype showed an increased release of il-1 after stimulation with lipopolysaccharide . recent studies suggest that the functional role of rs16944 may depend on il1b promoter region haplotypes including rs16944 [ 2326 ] . although the findings are inconsistent , these previous studies suggest that rs16944 could affect the expression levels of il-1. our report is the first demonstration of the involvement of il1b polymorphism in aerd . the sample size is relatively small , particularly in the aerd group , which may limit the statistical power , so it would be desirable to replicate our findings in an independent population . future studies must investigate whether this cytokine is released in the airways of aerd patients and whether its levels relate to genetic polymorphisms in the il1b gene . interleukin-8 has been implicated in asthma and found in high concentrations in bronchoalveolar lavage fluid of patients with acute asthma exacerbations . in fact , polymorphic il8 alleles ( 251 t and 781c ) have been associated with asthma in a european population [ 7 , 27 ] , but not in asthmatics of korean origin ; the differences could be explained by the different ethnic populations studied . in contrast , korean asthmatics were found to show four nonsynonymous amino acid substitutions in the il-8 receptor a ( il8ra ) and an association of one synonymous variation in il8rb . in the present study , we did not find a significant difference in the rs4073 a / t between the aerd group and ata patients .