Background
Indoleamine 2,3‐dioxygenase (IDO), which degrades tryptophan (Trp) to kynurenine (Kyn), has been demonstrated to contribute to modulation of allergic responses. However, the role of IDO in ...food allergy has not yet been elucidated.
Methods
Serum Trp and Kyn concentrations were analyzed by high‐pressure liquid chromatography. Expression of IDO gene was measured by real‐time PCR. The levels of interleukin (IL)‐4, IL‐10, and interferon (IFN)‐γ in cell culture supernatants were measured by ELISA.
Results
Kyn/Trp (IDO activity) was significantly lower in subjects with food allergy (n = 100) than in aged‐matched healthy controls (n = 112) (P = 0.004). Kyn/Trp was decreased from healthy through completely tolerant, partially tolerant, and reactive ones LN transformation (mean ± SEM) healthy: 3.9 ± 0.02 μM/mM; completely tolerant: 3.83 ± 0.04; partially tolerant: 3.8 ± 0.06; reactive: 3.7 ± 0.04 (P = 0.008). The frequency of genetic polymorphisms of IDO did not reveal a significant association with Trp, Kyn, and Kyn/Trp in healthy and food‐allergic cases. Culture of PBMC experiments yielded that IDO mRNA expression was not different between tolerant and reactive groups. IL‐4 synthesis when stimulated with casein increased significantly in subjects who are reactive and tolerant to foods (P = 0.042, P = 0.006, respectively). Increase in IL‐10 synthesis was observed only in children tolerant to milk, but not in reactive ones. IFN‐γ synthesis, when stimulated with IL‐2 and β‐lactoglobulin in cell culture, was significantly higher in subjects tolerant to milk than in the reactive ones (P = 0.005 and P = 0.029, respectively).
Conclusion
Our results imply the probability of involvement of IDO in development of tolerance process, and we presume that high IDO activity is associated with nonresponsiveness to food allergens despite allergen sensitization.
Abstract
MicroRNAs (miRNAs) are noncoding RNAs that play an important role in the regulation of inflammation and have not been evaluated in exhaled breath condensates (EBC) of patients with ...esophageal atresia and tracheoesophageal fistula (EA–TEF). It is aimed to evaluate the levels of miRNA-21 and miRNA-24 in EBC of patients with EA–TEF.
Patients who received surgery for EA–TEF (EA) were assessed for age, sex, types of anomaly, surgical treatments, and respiratory problems. A 500–1000 mL of EBC was obtained from each participant with EcoScreen. The levels of miRNA-21 and miRNA-24 in the EBC were analyzed by real-time polymerase chain reaction and compared between the EA group and the control group consisting of healthy children with no history of respiratory problems (n = 17). The levels of miRNAs in relation to respiratory problems and gastroesophageal reflux (GER) were also assessed. A total of 19 patients were enrolled in the EA group with a mean age of 7.8 ± 3.2 years and a male-to-female ratio of 10:9 EA cases had significantly lower levels of miRNA-21 (P < 0.05) compared to that in control group. The miRNA-24 levels did not differ between groups (P > 0.05). EA patients with positive pH testing for GER (n = 6) and fundoplication (n = 6) had higher levels of miRNA-21 than those with normal pH testing and without fundoplication, respectively (n = 13, P < 0.05). The levels of miRNA-21 and miRNA-24 did not differ between patients with and without proton pump inhibitor treatment (P > 0.05).
The lower levels of miRNA-21 in the EBC of EA patients suggest a hyperreactive airway problem, which may be associated with GER and its surgical treatment.
There is ample evidence for the existence of a systemic oxidative stress in childhood asthma but relatively little information on the oxidant stress in the airways. To determine the extent of ...oxidant/antioxidant imbalance and describe its determinants in the airways of asthmatic children including asthma severity and the genotype of the antioxidant enzymes. One hundred and ten children with mild asthma, 30 children with moderate asthma and 191 healthy controls were included in the study. Exhaled breath condensate (EBC) was collected from all children with EcoScreen®. Levels of malondialdehyde were measured as the indicator of oxidative stress, and of reduced glutathione as the indicator of antioxidant defense. Children were genotyped for the presence of null variants of glutathione S transferase (GST) T1 and GSTM1, and ile105val variant of GSTP1. Risk factors were analyzed with multivariate logistic regression. EBC contained significantly higher levels of malondialdehyde and lower levels of reduced glutathione in asthmatic children compared with healthy controls (P < 0.001 for each), whereas there was no difference between mild and moderate asthmatics. Multivariate logistic regression identified asthma as the only independent factor contributing to oxidative stress. Genotypes of the antioxidant enzymes had no effect on the oxidative burden. Asthma is associated with an extremely powerful oxidative stress not only in the systemic circulation but also in the airways.
Oxidative Stress and Antioxidant Defense Birben, Esra; Sahiner, Umit Murat; Sackesen, Cansin ...
The World Allergy Organization journal,
01/2012, Letnik:
5, Številka:
3
Journal Article
Recenzirano
Odprti dostop
Reactive oxygen species (ROS) are produced by living organisms as a result of normal cellular metabolism and environmental factors, such as air pollutants or cigarette smoke. ROS are highly reactive ...molecules and can damage cell structures such as carbohydrates, nucleic acids, lipids, and proteins and alter their functions. The shift in the balance between oxidants and antioxidants in favor of oxidants is termed "oxidative stress." Regulation of reducing and oxidizing (redox) state is critical for cell viability, activation, proliferation, and organ function. Aerobic organisms have integrated antioxidant systems, which include enzymatic and non-enzymatic antioxidants that are usually effective in blocking harmful effects of ROS. However, in pathological conditions, the antioxidant systems can be overwhelmed. Oxidative stress contributes to many pathological conditions and diseases, including cancer, neurological disorders, atherosclerosis, hypertension, ischemia/perfusion, diabetes, acute respiratory distress syndrome, idiopathic pulmonary fibrosis, chronic obstructive pulmonary disease, and asthma. In this review, we summarize the cellular oxidant and antioxidant systems and discuss the cellular effects and mechanisms of the oxidative stress.
Background
Genetic variants in endotoxin signaling pathway are important in modulating the effect of environmental endotoxin on asthma and atopic phenotypes. Our objective was to determine the single ...nucleotide polymorphisms (SNPs) in the endotoxin signaling pathway that may influence in vitro IgE synthesis and to investigate the relationship between these variants and endotoxin exposure in relation to the development of asthma and atopy in a birth cohort.
Methods
Peripheral blood mononuclear cells from 45 children with asthma were stimulated with 2 and 200 ng/ml lipopolysaccharide in vitro and IgE was measured in the culture supernatants. Children were genotyped for 121 SNPs from 30 genes in the endotoxin signaling pathway. Variants with a dose–response IgE production in relation to lipopolysaccharide (LPS) were selected for replication in a population‐based birth cohort, in which we investigated the interaction between these SNPs and endotoxin exposure in relation to airway hyper‐responsiveness, wheeze, and atopic sensitization.
Results
Twenty‐one SNPs in nine genes (CD14, TLR4, IRF3, TRAF‐6, TIRAP, TRIF, IKK‐1, ST‐2, SOCS1) were found to modulate the effect of endotoxin on in vitro IgE synthesis, with six displaying high linkage disequilibrium. Of the remaining 15 SNPs, for seven we found significant relationships between genotype and endotoxin exposure in the genetic association study in relation to symptomatic airway hyper‐responsiveness (CD14‐rs2915863 and rs2569191, TRIF‐rs4807000), current wheeze (ST‐2‐rs17639215, IKK‐1‐rs2230804, and TRIF‐rs4807000), and atopy (CD14‐rs2915863 and rs2569192, TRAF‐6‐rs5030411, and IKK‐1‐rs2230804).
Conclusions
Variants in the endotoxin signaling pathway are important determinants of asthma and atopy. The genotype effect is a function of the environmental endotoxin exposure.
Background: Endotoxin, with its potential to enhance type 1 immunity, is a significant player in the hygiene hypothesis. The combined effects of the genetic variants of various molecules in the ...endotoxin response pathway on asthma related phenotypes are largely unknown.
Objective: To investigate the effects of the genetic variants of CD14 and TLR4 genes on asthma phenotypes in a large number of asthmatic children.
Methods: 613 asthmatic children were genotyped at the CD14‐C159T, TLR4‐A896G and TLR4‐C1196T loci. IgE, eosinophil numbers and FEV1 were compared in 327 children who were not on any controller medications and were symptom free. Multivariate logistic regression was used to determine the factors associated with total IgE.
Results: Among children with atopic asthma, total IgE levels were significantly different among the three genotypes in the co‐dominant model CC: 435 kU/l (interquartile range: 146–820); CT: 361 (140–710); TT 204 (98–435), P = 0.035. TT genotype was significantly and independently associated with lower IgE levels (OR: 0.5 95%; CI = 0.28–0.90, P = 0.021). Both TLR4‐A896G and TLR4‐C1196T polymorphisms were more frequent in the mild asthma group with atopy (P = 0.032, 0.018, respectively). The combined effects of the genetic variants in CD14 and TLR4 genes did not improve the observed associations.
Conclusion: Our study demonstrates that the CD14‐C159T promoter variant influences total IgE levels and also indicates that the T allele has a more profound effect on total IgE in children with atopic asthma. Polymorphisms in the TLR4 gene may be associated with milder forms of disease in atopic asthmatics in the population studied.
Background: The number of Sp1–Egr1 binding tandem repeats at the ALOX5 promoter influences gene transcription and may modify the response to anti‐leukotriene treatment. The relationship of ALOX5 ...variants to asthma severity and leukotriene production by eosinophils is unknown.
Objective: To characterize ALOX5 mRNA expression and cysteinyl‐leukotriene production by eosinophils from individuals bearing ALOX5 promoter deletional variants and their association with the severity of childhood asthma.
Methods: Eosinophils from adult asthmatics bearing only variant alleles (with other than five tandem repeats on both chromosomes, non5/non5) or no variant alleles (5/5) were cultured in vitro and ALOX5 expression and leukotriene secretion were measured. A total of 621 children with mild or moderate‐severe asthma were genotyped at the ALOX5 core promoter.
Results: Asthmatics with non5/non5 genotype expressed less ALOX5 mRNA and produced less LTC4 into culture supernatants than 5/5 individuals (6.4 ± 2.0 and 20.0 ± 5.0 pg/ml, n = 5; P < 0.05). More asthmatic children bearing non5/non5 genotype had moderate‐severe asthma than children with the 5/5 genotype (5.3% vs. 1.4%, P = 0.008). Multivariate logistic regression identified ALOX5 promoter genotype as a significant predictor of disease severity (OR = 3.647, 95% CI: 1.146–11.608, P = 0.03). Consistent with these findings, children bearing the non5/non5 genotype had greater bronchomotor response to exercise as measured by the maximum fall after exercise and the area under the exercise curve (P < 0.05 for both).
Conclusion: Our results suggest that children who express the asthma phenotype despite having a genetic variant that impairs their ability to express ALOX5 have more severe disease and thus are more likely to have asthma symptoms.
To cite this article: Sackesen C, Birben E, Soyer OU, Sahiner UM, Yavuz TS, Civelek E, Karabulut E, Akdis M, Akdis CA, Kalayci O. The effect of CD14 C159T polymorphism on in vitro IgE synthesis and ...cytokine production by PBMC from children with asthma. Allergy 2011; 66: 48-57. ABSTRACT: Background: Even though the genotype at the promoter region of the CD14 molecule is known to affect the atopic phenotypes, the cellular and molecular basis of this association is largely unknown. Objective: To investigate the effect of lipopolysaccharide (LPS) on IgE production and cytokine profile by peripheral blood mononuclear cells (PBMC) obtained from asthmatic children with the TT and the CC genotypes at position −159 of the CD14 gene. Methods: Peripheral blood mononuclear cells from asthmatic children with alternative genotypes at CD14 C159T locus were stimulated with 2 and 200 ng/ml LPS in vitro. The IgE, IgG and, IgM response was determined by ELISA and Ig έ-germline, IgG, and IgM transcription by real-time PCR. A cluster of cytokines was measured by cytometric bead array. Results: Asthmatic children with the TT genotype but not those with the CC genotype responded with increased IgE synthesis and germline transcription to LPS stimulation. There were no genotype-related differences in IgG and IgM. TT but not the CC genotype was associated with significantly increased interleukin (IL)-4/IL-12 and IL-4/interferon-gamma (IFN-γ) ratios in the culture supernatant. There were no genotype-related differences in IL-1β, IL-7, IL-10, IL-13, IL-17A, granulocyte colony stimulating factor, granulocyte macrophage colony stimulating factor, monocyte chemotactic protein, and tumor necrosis factor alpha. Conclusion: Peripheral blood mononuclear cells from asthmatic children with the TT genotype at position −159 of the CD14 gene make more IgE than those with the CC genotype following LPS stimulation because of increased germline transcription and have an augmented Th2 cytokine profile.
The development of allergic hypersensitivity depends on both genetic and environmental factors. Different amounts of microbial products could affect patients with atopy and different genotypes.
We ...aimed to evaluate the role of varying degrees of exposure to infection by Mycobacterium tuberculosis (tuberculosis) in atopic patients and analyze the association with genetic factors.
We performed CD14-159C/T genotyping in atopic patients (n=118) and healthy individuals (n=62) and recorded the following variables: rural lifestyle, exposure to persons with tuberculosis, bacille Calmette-Guerin (BCG) vaccination, tuberculin skin test (TST), skin prick test, and phenotypes of atopy. Blood samples were analyzed for soluble-CD14 (sCD14), interferon (IFN) y, total immunoglobulin (Ig) E, and eosinophil levels. A score was used to identify the likelihood of exposure to tuberculosis.
Almost all the study participants had had a BCG vaccination, and half had a positive TST result. No differences were observed between atopic patients with high/low tuberculosis scores and CD14 genotypes in terms of atopic phenotypes, allergen sensitization, and levels of total IgE, sCD14, and IFN-y. However, the frequency of asthma was higher in atopic patients with a high tuberculosis score and was not associated with CD14 genotypes. Eosinophil counts in blood were higher in atopic patients with a high tuberculosis score and CC+CT genotypes.
These results suggest that the C allele of the CD14-159C/T polymorphism has a marked effect on eosinophil levels in atopic patients with increased exposure to tuberculosis. In addition, the degree of exposure to tuberculosis in atopic patients may modify the development of asthma.
Previous genetic studies have associated the region of the human genome (14q22.1) containing the gene for the prostanoid DP receptor (PTGDR) with asthma. A study of a mouse model suggests that the ...receptor is required for the expression of the asthma phenotype. Our associations of asthma with functional genetic variants of PTGDR link these observations.
We identified and evaluated combinations of genetic variants that influence PTGDR transcription for disease association in case-control studies of 518 white patients with asthma and 175 white controls and 80 black patients with asthma and 45 black controls.
We identified four novel and two previously reported single-nucleotide polymorphisms (SNPs) in PTGDR and its vicinity. These define four common three-SNP haplotypes, which vary in their ability to support transcription of PTGDR and have distinct DNA-binding-protein affinity profiles. Individual PTGDR SNPs were significantly associated with asthma in both populations. Specific PTGDR haplotypes were significantly associated with a diagnosis of asthma in a large case-control study of whites (P=0.002); we confirmed these findings in a second population of blacks (P=0.01). Multivariate analysis of the haplotype combinations (diplotypes) demonstrated that both whites (odds ratio, 0.55; 95 percent confidence interval, 0.38 to 0.80; P=0.002) and blacks (odds ratio, 0.32; 95 percent confidence interval, 0.12 to 0.89; P=0.03) who had at least one copy of the haplotype with a low transcriptional efficiency had a lower risk of asthma than subjects with no copies of the haplotype.
Our functional and genetic findings identify PTGDR as an asthma-susceptibility gene.
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