Serum interleukin-5 in aspirin-induced asthma

BACKGROUND: Eosinophilopoetic cytokine IL-5 enhances cysteinyl-leukotriene (cys-LT) synthesis in eosinophils in vitro. In patients with aspirin-induced asthma (AIA) bronchial biopsies revealed eosinophil infiltration and a marked increase in IL-5 positive cells. OBJECTIVE: We wondered whether in AIA patients the bronchial IL-5 increase is reflected in peripheral blood, and if so, whether it is related to overproduction of cys-LT. METHODS: In 11 stable patients with AIA, 32 with ATA (aspirin-tolerant asthma) and in 16 controls we measured serum IL-5 concentrations and urinary LTE4, believed to reflect global cys-LT production. RESULTS: Serum IL-5 was detectable in 12 of 43 asthmatics, but in none of the control subjects. It was highest in the ATA group and differed significantly from the controls. There was no significant difference in IL-5 levels between: (i) the asthmatic groups studied, and (ii) AIA patients and controls. No relationship was found between serum IL-5 and urinary cys-LT. CONCLUSION: Overexpression of IL-5 reported in the airways of aspirin-sensitive patients with asthma was not reflected in their blood. If IL-5 affects cys-LT production, it is rather in the bronchi of the patients than in the blood.     

Specific immunoglobulin E for staphylococcal enterotoxins in nasal polyps from patients with aspirin-intolerant asthma

BACKGROUND: Nasal polyps infiltrated with eosinophils are commonly found in chronic asthmatic patients, more frequently in those with aspirin-intolerant asthma (AIA) than aspirin-tolerant asthma (ATA). Some studies have suggested a contribution of superantigens derived from Staphylococcus sp to nasal polyposis and eosinophilia, but their relative importance in AIA and ATA subjects is unknown. OBJECTIVE: We investigated whether local production of specific IgE to staphylococcal enterotoxins A and B (SEA and SEB) and relationships with markers of eosinophilic inflammation differ in the nasal polyps of AIA and ATA subjects. METHODS: Fifteen AIA subjects with positive responses to lysine-aspirin bronchoprovocation and 15 ATA subjects underwent polypectomy. Immunoassays were used to quantify eosinophil cationic protein (ECP), IL-5, mast cell tryptase, soluble IL-2 receptors (sIL-2R), total IgE, and specific IgE for SEA and SEB. RESULTS: ECP levels in nasal polyp homogenates were higher in AIA subjects than in ATA subjects (P < 0.02), with no significant differences in tryptase, IL-5 or sIL-2R. Total IgE, and specific IgE to both SEA and SEB, were detectable in some nasal polyps from both subject groups, but median levels were markedly higher in AIA subjects than in ATA subjects (P = 0.04, 0.01, 0.05, respectively). Levels of specific IgE to SEA and SEB correlated significantly with levels of ECP and IL-5, but not those of tryptase or sIL-2R. CONCLUSION: These findings suggest that staphylococcal superantigens may drive local eosinophilic inflammation in nasal polyp tissue, and that this is exacerbated in subjects with AIA.     

Increased expression of lipoxygenase enzymes during pollen season in nasal biopsies of pollen-allergic patients

BACKGROUND: Exposure of patients sensitized to pollen triggers development of seasonal allergic rhinitis symptoms (SAR). Eicosanoids are a group of arachidonic acid metabolites contributing to the symptoms of SAR. The aim of this study was to investigate seasonal changes in the expression of enzymes of the eicosanoid pathway in the nasal mucosa of patients with SAR. METHODS: Twenty SAR patients allergic to birch or grass and eight healthy subjects were included in the study. Patients registered rhinoconjunctivitis symptoms and use of rescue medication before and during the pollen season. Nasal biopsies were obtained before and around the peak of the season, sectioned and stained using markers for eosinophils, mast cells, T cells and neutrophils. Antibodies against the following enzymes were also used: cyclo-oxygenase (COX-1, COX-2), 5-lipoxygenase (5-LO), 5-lipoxygenase-activating factor (FLAP), LTA4 hydrolase (LTA4h) and LTC4 synthase (LTC4s). RESULTS: During the pollen season symptoms of rhinoconjunctivitis and medication score increased significantly (P=0.001; P=0.001 respectively). During the pollen season numbers of eosinophils (P=0.02) and cell positive 5-LO (P=0.02), LTC4s (P=0.04) and LTA4h (P=0.02) increased significantly. During season number of mast cells and cells expressing 5-LO and LTA4h were higher in SAR than in healthy controls group (P=0.02; P=0.01; P=0.03 respectively). CONCLUSION: In sensitized patients exposure to pollen allergen results in increased expression of enzymes of the eicosanoid pathway.     

Bronchial mast cells are the dominating LTC4S-expressing cells in aspirin-tolerant asthma

The increased bronchial production of leukotriene C4 (LTC4) in asthma is assumed to derive from infiltrating eosinophils expressing LTC4-synthase (LTC4S). Multicolor immunohistofluorescence examination of bronchial cryosections from 30 treated, untreated, or bronchial antigen-provoked aspirin-tolerant individuals with asthma and nine control subjects revealed that the dominating LTC4S-expressing cells were mast cells (> 80%), and not eosinophils. Whereas 95% of the mast cells expressed high levels of LTC4S, only 8-27% of the eosinophils expressed low levels. Image analysis revealed a significantly higher LTC4S expression levels in mast cells than in eosinophils. The bronchial mRNA levels for LTC4S did not correlate with the densities of LTC4S-positive eosinophils or mast cells. Treated individuals with asthma with more than 12% reversibility had significantly higher density of LTC4S-positive mast cells than those with less reversibility, and it correlated significantly with reduction in lung function (FEV1-predicted), both before and after salbutamol inhalation. Thus, mucosal mast cells, and not eosinophils, were the dominating LTC4S-containing cells in both untreated and treated aspirin-tolerant asthma. The density of LTC4S-positive mast cells correlated, moreover, with both the reduction in lung function and the degree of reversibility in treated asthma.     

Expression of cysteinyl leukotriene synthetic and signalling proteins in inflammatory cells in active seasonal allergic rhinitis

BACKGROUND: Cysteinyl leukotrienes (CysLTs) are bioactive lipids that have been shown to contribute to allergic and inflammatory diseases. Eosinophils and mast cells have the capacity to produce large amounts of CysLTs after allergic or non-allergic stimulation. Molecular identification of both the synthetic and signalling proteins in the CysLT pathway allows the investigation of expression of the CysLT enzymes and receptors in active allergic rhinitis. OBJECTIVE: We examined the expression of the proteins involved in the synthesis of CysLTs and the cysteinyl leukotriene-1 (CysLT1) and cysteinyl leukotriene-2 (CysLT2) receptors in inflammatory cells from patients with active seasonal allergic rhinitis. METHODS: Nasal lavage samples were obtained from patients during active seasonal allergic rhinitis. Specific cellular immunocytochemical techniques were used to detect the cysteinyl leukotriene synthetic proteins, namely 5-lipoxygenase (5-LO), 5-lipoxygenase-activating protein (FLAP) and leukotriene C4 synthase (LTC4S). In situ hybridization and immunocytochemical techniques were used to identify the mRNA and proteins for the CysLT1 and CysLT2 receptors. RESULTS: 5-LO, FLAP and LTC4S, and the CysLT1 and CysLT2 receptors were expressed in the majority of eosinophils and in subsets of mast cells and mononuclear cells. 5-LO, FLAP and the CysLT1 receptor, but not LTC4S or the CysLT2 receptor, were expressed in a subset of nasal neutrophils. CONCLUSIONS: Our study demonstrates the presence of CysLT pathway proteins in key allergic and inflammatory cells from the upper airway of patients with active seasonal allergic rhinitis. Our expression data highlight the potential of CysLT-modifying agents to treat both upper and lower airway symptoms in patients suffering from allergic rhinitis and asthma.     

Up-regulation of prostaglandin biosynthesis by leukotriene C4 in elicited mice peritoneal macrophages activated with lipopolysaccharide/interferon-{gamma}

Leukotrienes (LT) and prostaglandins (PG) are proinflammatory mediators generated by the conversion of arachidonic acid via 5-lipoxygenase (5-LO) and cyclooxygenase (COX) pathways. It has long been proposed that the inhibition of the 5-LO could enhance the COX pathway leading to an increased PG generation. We have found that in in vitro models of inflammation, such as mice-elicited peritoneal macrophages activated with lipopolysaccharide (LPS)/interferon-gamma (IFN-gamma), the deletion of the gene encoding for 5-LO or the enzyme activity inhibition corresponded to a negative modulation of the COX pathway. Moreover, exogenously added LTC(4), but not LTD(4), LTE(4), and LTB(4), was able to increase PG production in stimulated cells from 5-LO wild-type and knockout mice. LTC(4) was not able to induce COX-2 expression by itself but rather potentiated the action of LPS/IFN-gamma through the extracellular signal-regulated kinase-1/2 activation, as demonstrated by the use of a specific mitogen-activated protein kinase (MAPK) kinase inhibitor. The LT-induced increase in PG generation, as well as MAPK activation, was dependent by a specific ligand-receptor interaction, as demonstrated by the use of a cys-LT1 receptor antagonist, although also a direct action of the antagonist used, on PG generation, cannot be excluded. Thus, the balance between COX and 5-LO metabolites could be of great importance in controlling macrophage functions and consequently, inflammation and tumor promotion.     

Effects of pranlukast on aspirin-induced bronchoconstriction: differences in chemical mediators between aspirin-intolerant and tolerant asthmatic patients.

BACKGROUND: Aspirin inhibits cyclooxygenase activity and modifies production of the arachidonate cascade in aspirin-induced asthma. The aim of the present study was to examine the effects of leukotriene (LT) receptor antagonist on aspirin challenge on eosinophil activity and chemical mediators released into the airway of asthmatic patients. METHODS: Aspirin oral provocation test was performed in aspirin-intolerant asthmatic patients (AIA; N = 7) and aspirin-tolerant asthmatic patients (ATA; N = 7). In AIA, LT receptor antagonist (pranlukast) was administered orally 2 hours before the test, and its inhibitory effects on sputum LTC4+C4, eosinophil cationic protein (ECP), eosinophil count, urinary LTE4/creatinine (Cr), 11-dehydrothromboxane (11-dhTX) B2/Cr, serum LTC4+D4, ECP, and peripheral blood eosinophil count were compared with the findings in ATA subjects. RESULTS: In AIA, aspirin induced an immediate reaction associated with increased urinary LTE4/Cr and sputum ECP and a fall in urinary 11-dhTXB2/Cr. Pranlukast inhibited the bronchial reaction and an increase in sputum ECP after threshold dosed of ASA, but failed to change aspirin-induced LT production in sputum and urine. In ATA, aspirin challenge was only associated with a fall in urinary 11-dhTXB2. CONCLUSIONS: Our results indicated that aspirin-induced asthma is associated with overproduction of LT with a shift to the 5-lipoxygenase series of the arachidonate cascade and that leukotriene receptor antagonist are useful for AIA through inhibition of production of LT and eosinophilic inflammation in the airway.     

Uncoupled regulation of leukotriene C4 synthase in platelets from aspirin-intolerant asthmatics and healthy volunteers after aspirin treatment

BACKGROUND: We have reported that thromboxane A2 induces suppression of leukotriene (LT) C4 synthase activity in human platelets. AIM: In the present study, we describe a mechanism whereby aspirin treatment can lead to increased formation of LTC4, which is a potent bronchoconstrictor and inflammatory mediator. This mechanism is also demonstrated to be present in platelets from aspirin-intolerant asthmatics (AIA). METHODS: The effect of arachidonic acid or platelet agonists on LTC4 synthase activity was investigated in platelets obtained from healthy volunteers, aspirin-intolerant asthmatics or aspirin-tolerant asthmatics after in vivo treatment or in vitro pre-incubation with aspirin. RESULTS: Incubation of normal platelets with arachidonic acid or collagen provoked approximately 50% reduction of platelet LTC4 synthase activity, as determined by the conversion of LTA4 to LTC4. However, the inhibitory effect of arachidonic acid or collagen was not observed after oral administration of aspirin prior to collection of the platelets. Arachidonic acid-induced inhibition of LTC4 synthase activity was totally abolished in platelets collected from peripheral blood already 30 min after aspirin ingestion but was fully restored in platelets collected 3 to 7 days after the administration of aspirin. Treatment of platelet suspensions with aspirin in vitro dose-dependently counteracted the suppressive effect of arachidonic acid on LTC4 formation, with total reversal at approximately 40 microm. In contrast, the major aspirin metabolite, salicylic acid did not alter arachidonic acid-induced reduction of LTC4 synthase activity. Similarly, LTC4 synthase activity in platelets from AIA and aspirin-tolerant asthmatics (ATA) was reduced by approximately 50% after pre-treatment with arachidonic acid in vitro. Again the inhibitory effect was abolished when platelets were pre-incubated in the presence of aspirin. CONCLUSION: The results indicate that oral aspirin administration can lead to uncoupling of thromboxane A2-dependent negative feedback mechanisms, which may normally restrict the production of cysteinyl leukotrienes. This mechanism can be of potential interest in aspirin-induced asthma.     

Leukotriene C4 synthase promoter polymorphism in Japanese patients with aspirin-induced asthma

BACKGROUND: The A to C transversion in the promoter region of the gene encoding leukotriene C4 synthase (LTC4S) is proposed to be associated with the development of aspirin-induced asthma (AIA). OBJECTIVE: We investigated the frequency of the polymorphism in Japanese population and its association with clinical characteristics and cysteinyl leukotriene production. METHODS: Genotyping of LTC4S gene promoter was performed on 60 patients with AIA, 100 patients with aspirin-tolerant asthma (ATA), and 110 control subjects. We assessed the basal levels of urinary LTE4, the increment of urinary LTE4 on venous aspirin challenge, and LTC4S activity in peripheral blood eosinophils. RESULTS: The frequency of the variant C allele was significantly higher in patients with AIA (frequency of allele [q] = 0.192) than in patients with ATA (q = 0.110, P =.042). Variant C-allelic carriers experienced asthma at a significantly younger age (31.8 +/- 2.9 years [mean +/- SEM]) than wild-type A homozygotes (41.3 +/- 2.2 years, P =.007). Basal levels of LTE4 and the increment of urinary LTE4 on venous aspirin challenge did not show a difference between wild-type A homozygotes and variant C-allelic carriers. There was no relationship between the polymorphism and the LTC4S activity in eosinophils, although LTC4S activities were significantly higher in patients with AIA than in patients with ATA. CONCLUSION: Our findings reveal the lack of functionality of the polymorphism in the LTC4S gene, whereas this polymorphism might have some effect on the development of AIA, probably in linkage disequilibrium with another causatively important mutation.     

Matrix metalloproteases in vernal keratoconjunctivitis, nasal polyps and allergic asthma

BACKGROUND: Allergic conditions in different organs share many similarities in their inflammatory response. Vernal keratoconjunctivitis (VKC), asthma and nasal polyps exhibit several similar, but site-specific mucosal structural changes. The aim of the study was to investigate whether matrix metalloproteases contribute to different tissue remodelling aspects in different organs. METHODS: Mucosal biopsies were obtained from conjunctiva of healthy donors, tarsal conjunctiva of vernal patients, bronchi of non-asthmatic subjects, bronchi of mild stable asthmatic patients, nasal mucosa of non-allergic donors and nasal polyps of allergic patients. Distribution of metalloprotease-1, -3, -9, -13, tissue inhibitor of metalloproteases-1, collagens I and III and the presence of eosinophils and CD4+ cells were evaluated by immunohistochemistry. RESULTS: Collagens were highly diffuse in the giant papillae of VKC and in nasal polyps, and yet less increased in the subepithelium of asthmatic patients. Immunostaining for metalloprotease-1, -3, -9 and -13 was significantly higher in VKC compared with normal conjunctiva. Metalloprotease-9 staining was higher in the stroma of polyps vs. normal nasal mucosa, and only metalloprotease-13 was significantly more expressed in asthmatic vs. non-asthmatic subjects. Metalloprotease-9 immunostaining was more intense in vernal compared with other tissues. In all pathological tissues, metalloprotease-9-positive staining was in association with eosinophils and CD4+ cells. CONCLUSIONS: Expression of metalloproteases may play an important role in inducing the structural changes seen in VKC, nasal polyps and asthma. Tissue remodelling and gelatinase immunoexpression was more dramatic in giant papillae of vernal patients compared with other tissue sites of chronic allergic inflammation.     

Polymorphisms of the PTGDR and LTC4S influence responsiveness to leukotriene receptor antagonists in Korean children with asthma

Activation of the prostaglandin D2 receptor (PTGDR) may contribute to pulmonary vasodilation, bronchoconstriction, recruitment of eosinophils, basophils and T-lymphocytes, and enhanced synthesis of leukotriene C4. We investigated whether polymorphisms of the leukotriene C4 synthase (LTC4S) -444A/C and PTGDR -441T/C were associated with clinical phenotypes and responsiveness to leukotriene receptor antagonist (LTRA) in Korean asthmatic children. We enrolled 270 normal and 870 asthmatic children. We prescribed montelukast (5 mg per day) to 100 of asthmatic children, and analyzed the responsiveness to LTRA by exercise challenge tests. Polymorphisms were genotyped by PCR-restriction fragment length polymorphism. As the number of minor alleles of the PTGDR -441T/C and LTC4S -444A/C polymorphisms increased, the log total eosinophil counts increased in atopic asthmatic children (P-value=0.03). We found a significant association between responsiveness to montelukast and the PTGDR polymorphism (P-value=0.038). However, the LTC4S -444A/C and PTGDR -441T/C were not associated with the susceptibility for asthma (LTC4S, AA versus AC+CC, adjusted odds ratio of 0.98 (95% confidence interval, 0.73-1.31); PTGDR, TT versus TC+CC, adjusted odds ratio of 0.90 (95% confidence interval, 0.68-1.19)) or clinical phenotypes (P-value>0.05). The effects of the PTGDR and LTC4S polymorphisms on the enhancement of eosinophil counts were additive in the Korean children with asthma. In addition, the PTGDR polymorphism seems to be associated with the responsiveness to LTRA. Therefore, therapies that target the PTGDR may be useful for modulating the responsiveness to LTRA.     

Decreased apoptosis and distinct profile of infiltrating cells in the nasal polyps of patients with aspirin hypersensitivity

BACKGROUND: Patients with aspirin-hypersensitive rhinosinusitis/asthma suffer from a severe form of hyperplastic rhinosinusitis with recurrent polyposis. We aimed to assess the presence of apoptotic cells in nasal polyps from aspirin-hypersensitive (AH) and aspirin-tolerant (AT) patients with rhinosinusitis as related to the characteristics of local inflammation. METHODS: Nasal polyps obtained from 16 AH patients and 36 AT patients (17 atopic and 19 nonatopic) were stained for eosinophils and metachromatic cells, and in parallel immunocytochemistry was performed to detect CD45RO+, HLA-DR+, CD8+ and CD68+ positive cells. Apoptotic cells were detected by a nick-end labelling technique, TUNEL. RESULTS: The density of apoptotic cells in AH polyps (5.5 + 1.5 cells/mm2) was significantly lower as compared to both atopic (18.7 + 3.8 cells/mm2; P < 0.02;) and nonatopic (21.3 + 5.2 cells/mm2; P < 0.01) AT polyps. The number of eosinophils, mast cells, and CD45RO+ cells were significantly increased in AH compared to AT polyps (P < 0.001), and the density of HLA-DR+ cells in AH patients was higher than in nonatopic (P < 0.02), but not in atopic AT patients. While in AH patients the duration of rhinosinusitis correlated inversely with the number of apoptotic cells (r = - 0.67; P < 0.04), in contrast, in AT atopic patients the duration of rhinosinusitis showed positive correlation with apoptosis (r = 0.89; P < 0.003). CONCLUSIONS: We conclude, that decreased apoptosis of inflammatory cells in nasal polyps from ASA-hypersensitive patients, reflects a distinct mechanisms of local inflammation and may be related to persistence and severity of the disease in these patients.     

Cell and cytokine profiles in nasal secretions from patients with nasal polyposis: effects of topical steroids and surgical treatment

BACKGROUND: Nasal polyposis (NP), a chronic inflammatory disease of the paranasal sinus mucosa, is frequently associated with asthma. Previous reports showed that surgical treatment for nasal polyps may influence asthma evolution. We hypothesized that sinus surgery may alter the cytokine network in nasal secretions. METHODS: We evaluated the characteristics (cells and mediators) of nasal lavages in nine patients with untreated NP (group A), 17 patients treated with topical steroids (group B), 21 patients treated by nasal surgery endonasal ethmoidectomy associated with topical steroids (group C), and 12 healthy subjects (controls). RESULTS: Percentages of both eosinophils and neutrophils were higher in NP patients than in controls. Percentages of eosinophils and interleukin-5 (IL-5) level were higher in group A than in group C and controls. There was a positive correlation between IL-5 and eosinophils. In marked contrast, IL-8, IL-10, and IL-1beta levels were significantly higher in group C than in groups A and B and controls; TNF-alpha concentration was significantly lower in group C than in groups A and B and controls; and there was a negative correlation between IL-10 and TNF-alpha. The percentage of eosinophils was higher in asthmatic patients with NP than in nonasthmatic patients. In addition, in group C, asthmatic patients also had a significantly higher level of IL-10 than nonasthmatic patients. CONCLUSIONS: Our study demonstrates that percentages of eosinophils and neutrophils, and IL-5 level were increased in nasal secretions from untreated patients with NP. Topical steroid treatment is associated with a decrease of inflammatory cells and mediators. In marked contrast, nasal surgery is associated with marked changes, in cytokine profile in nasal secretions, that are clearly different from those of controls and topical steroid-treated NP patients.     

Eosinophil activation status and corticosteroid responsiveness in severe asthma

BACKGROUND: Since eosinophils are implicated in asthma pathogenesis, we investigated whether these cells were activated in severe asthma. METHODS: Twenty-six asthmatics with different clinical responses to oral corticosteroid (CS), i.e. sensitive [change in forced expiratory volume in 1 s (DeltaFEV(1)) >/= 25% after oral methylprednisolone, 40 mg daily, for 14 days, n = 7], resistant (DeltaFEV(1) /= 20 mg oral prednisone daily for acceptable asthma control, n = 10), were studied. RESULTS: Calcium ionophore-induced leukotriene (LT) C(4) release of purified blood eosinophils was similar in the three groups. Cell incubation with granulocyte-macrophage colony-stimulating factor (GM-CSF) enhanced ionophore-induced LTC(4) release, and this effect was higher in CS-sensitive (5-fold) than in CS-resistant subjects (1.7-fold) (p = 0.02). CS treatment decreased blood eosinophil counts in these two groups of subjects (p 相似文献   

Association analysis of C6 genetic variations and aspirin hypersensitivity in Korean asthmatic patients

There has been increasing evidence that genetic mechanisms contribute to the development of aspirin-intolerant asthma (AIA), a life-threatening disease. The complement component (C6) is a constituent of a biochemical cascade that has been implicated in airway epithelial damage and nasal polyposis, and therefore, may be a risk factor for AIA. To investigate the association between C6 variations and AIA in a Korean asthma cohort, 27 SNPs were selected for genotyping based on previously reported polymorphisms in the HapMap database. Genotyping was carried out using TaqMan assay, and five major haplotypes were obtained in 163 AIA cases and 429 aspirin-tolerant asthma (ATA) controls subjects. Genotype frequency distributions of C6 polymorphisms and haplotypes were analyzed using logistic and regression models. Subsequent analyses revealed a lack of association between C6 genetic variations and AIA. From the initial analyses, marginal associations of rs10512766 (p = 0.04 in co-dominant model) and rs4957374 (p = 0.05 in dominant model) with AIA did not reach the threshold of significance after multiple testing corrections; thus this study failed to find convincing evidence that variations in C6 gene influence the risk of AIA in a Korean population. However, these preliminary results may contribute to the etiology of aspirin hypersensitivity in Korean asthmatic patients.     

Enhanced leukotriene C4 production by peripheral eosinophilic granulocytes from children with asthma

Granulocytes and mononuclear cells were isolated from the blood of asthmatic and healthy children. Stimulation with ionophore A 23187 induced a significantly higher leukotriene C4 (LTC4) generation from granulocytes of asthmatic children than from granulocytes of healthy controls. In contrast, mononuclear cells from patients and controls did not differ in their ability to produce LTC4. Additional analysis showed that the difference in LTC4 generation of granulocytes was due to increased formation but not to decreased oxidative degradation of LTC4. Analysis of LTC4 generation of purified neutrophils and eosinophils revealed that LTC4 was generated almost exclusively by eosinophils and, in particular, the hypodense population. Granulocytes from patients with a history of severe asthma displayed a higher LTC4 formation than granulocytes from patients with less severe disease.