Esra Birben

The effect of polymorphisms at the CD14 promoter and the TLR4 gene on asthma phenotypes in Turkish children with asthma

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.

Oxidative Stress in Asthma

Asthma is a chronic inflammatory lung disease that results in airflow limitation, hyperreactivity, and airway remodeling. There is strong evidence that an imbalance between the reducing and oxidizing systems favoring a more oxidative state is present in asthma. Endogenous and exogenous reactive oxygen species, such as superoxide anion, hydroxyl radical, hypohalite radical, and hydrogen peroxide, and reactive nitrogen species, such as nitric oxide, peroxynitrite, and nitrite, play a major role in the airway inflammation and are determinants of asthma severity. Asthma is also associated with decreased antioxidant defenses, such as superoxide dismutase, catalase, and glutathione. In this review, we will summarize the current knowledge and discuss the current and future strategies for the modulation of oxidative stress in asthma.

Oxidative stress and its determinants in the airways of children with asthma

Background:  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.

ALOX5 promoter genotype, asthma severity and LTC4 production by eosinophils

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.

Molecular, genetic and epidemiologic studies on selective complete C1q deficiency in Turkey.

Selective complete C1q deficiencies (SCDC1q) of the complement component C1q are rare genetic disorders with high prevalence of lupus-erythematosus-like symptoms and recurrent infections. Among the 41 published cases from 23 families, 10 derive from 6 Turkish families. One particular mutation leading to a stop codon in the C1q A gene was first identified in members of a Gypsy family from the Slovac Republic. Later the same mutation has been found in all cases in four SCDC1q families from Turkey suggesting that one particular defective allele may be present in the populations of Southeastern Europe and Turkey. This study was undertaken to investigate the frequency of C-->T mutation in exon II of C1qA gene in Turkish population by using allele-specific polymerase chain reaction (PCR) and PCR-restriction fragment length polymorphism (PCR-RFLP). Among the 1544 patients from 15 pediatric departments and an additional 89 SLE patients of various ages no C1qA gene mutation was found. There were 43 heterozygous and 4 homozygous mutations in 161 family members or relatives investigated from the 4 families known with SCDC1q. Among the 223 inhabitants who were nonrelative to the 3 SCDC1q families living in the same village were screened for mutation and one heterozygous individual was observed. Although this mutant allele appears to be at a low prevalence in the population tested, individuals with recurrent infections or symptoms of lupus erythematosus-like syndrome should be tested for this mutation to rule out this type of C1q deficiency.

The effect of CD14-C159T genotypes on the cytokine response to endotoxin by peripheral blood mononuclear cells from asthmatic children

BACKGROUND A C-T polymorphism at position 159 in the promoter of CD14 (C-159T) modulates the cellular response to endotoxin and significantly influences total IgE levels. The effect of this genetic variant on the cytokine response of the inflammatory cells is incompletely understood. OBJECTIVE To investigate the effects of CD14-C159T genotypes on the response to endotoxin by peripheral blood mononuclear cells (PBMCs) in children with asthma. METHODS The PBMCs from asthmatic children with the TT (n = 11) and CC (n = 11) genotypes at the CD14 promoter were cultured in the presence of endotoxin, 100 ng/mL; concanavalin A, 10 microg/mL; or medium alone. Concentrations of soluble CD14 (sCD14), interleukin (IL) 1beta, IL-4, IL-10, IL-12, IL-13, interferon-gamma, and transforming growth factor beta were determined in culture supernatants by enzyme-linked immunosorbent assay, and the transcriptional differences were evaluated using reverse-transcriptase polymerase chain reaction. RESULTS Under unstimulated conditions, children with the TT genotype produced higher levels of sCD14 into the culture supernatant compared with children with the CC genotype (P = .03, Mann Whitney U test). Both IL-10 and IL-1beta concentrations were significantly higher in culture supernatants of children with the TT genotype after endotoxin stimulation (P = .02 and P = .009, respectively, by analysis of covariance [ANCOVA]). Messenger RNA expression was consistent with the results of protein concentration for IL-10 and sCD14. Concanavalin A stimulation resulted in lower levels of IL-4 in children with the TT genotype (P = .02, ANCOVA). CONCLUSION The genotype at the CD14 promoter C159T locus may significantly influence the cytokine response of PBMCs obtained from asthmatic children. Differences in IL-10 and IL-4 production by alternative genotypes may contribute to the observed genotype effect on total IgE.

The effect of CD14 C159T polymorphism on in vitro IgE synthesis and cytokine production by PBMC from children with asthma.

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.

Cellular Allergen Stimulation Test with Acetylsalicylic Acid-Lysine Is Not a Useful Test to Discriminate between Asthmatic Patients with and without Acetylsalicylic Acid Sensitivity

Background: The aspirin provocation test, considered to be the gold standard in the diagnosis of aspirin sensitivity, may be associated with severe adverse reactions; thus, alternative procedures with a higher safety profile are highly desirable. Although the cellular antigen stimulation test (CAST) has been proposed to be such an alternative, there is limited information about its clinical usefulness. Objective: It was the aim of our study to evaluate the clinical usefulness of CAST in the diagnosis of aspirin sensitivity. Material and Methods: Patients with aspirin-sensitive asthma and/or nasal polyps (n = 40), patients with aspirin-tolerant asthma and/or nasal polyps (n = 13) and healthy volunteers (n = 26) were included. A 2-day, single-blind placebo-controlled oral aspirin provocation test was performed. In vitro release of cysteinyl leukotrienes (Cys-LTs) by peripheral blood leukocytes was measured after stimulation with both stimulation buffer and lysine aspirin (2.5 mg/ml) by CAST. Results: Baseline Cys-LT levels were similar among the 3 groups. After lysine aspirin stimulation, the net increase in Cys-LTs was significantly higher in patients with aspirin sensitivity (median 91 pg/ml, interquartile range 22–206) compared with aspirin-tolerant patients (20 pg/ml, range 0–46) and healthy controls (23 pg/ml, range 0–71; p = 0.004). The assay had a sensitivity of 25%, a specificity of 92.3%, and positive and negative predictive values of 28.7 and 90.7%, respectively. Conclusion: Although the leukocytes of patients with aspirin sensitivity produce higher amounts of Cys-LTs as measured by CAST, the low sensitivity and predictive values limit the clinical usefulness of this test in the diagnosis of aspirin sensitivity.

The role of CD14 gene promoter polymorphism in tuberculosis susceptibility.

BACKGROUND CD14 is expressed principally by cells of monocyte/macrophage lineage and plays a pivotal role in the innate immunity to intracellular infections. Recent research findings have revealed an association between the CD14 gene promoter polymorphism and several major infectious diseases. OBJECTIVE The aim of the present study was to investigate the association between the CD14-159C/T polymorphism and tuberculosis in a Turkish population. METHODS For this purpose, 88 consecutive patients with tuberculosis (63 pulmonary, 25 extrapulmonary) and 116 control subjects were enrolled into a prospective study. We determined CD14-159 genotypes by polymerase chain reaction - restriction fragment length polymorphism analysis and also measured serum concentrations of soluble CD14 (sCD14) by using a quantitative sandwich enzyme immunoassay technique. RESULTS There was no significant difference in terms of genotype distribution between patients with tuberculosis (CC 18.2%, CT 48.9%, TT 33.0%) and controls (CC 12.9%, CT 50.9%, TT 36.2%) or between patients with pulmonary and extrapulmonary tuberculosis. Serum levels of sCD14 were significantly increased in patients with active tuberculosis compared to those with inactive tuberculosis and healthy controls (p<0.001). However, levels of sCD14 were not associated with any genotypes of CD14-159. CONCLUSION The genotyping findings of the present study do not support a role for the CD14-159C/T polymorphism in the development of tuberculosis, at least in the geographical region of central Anatolia. Significantly elevated serum sCD14 levels in patients with active disease reflect the importance of the mononuclear phagocytic system activation in tuberculosis.

Role of 90K protein in asthma and TH2-type cytokine expression.

BACKGROUND The 90K protein (mac-2 binding protein) is a member of the macrophage scavenger receptor cysteine-rich domain superfamily. Although systemic levels of 90K protein have been correlated with inflammation in many diseases, its role in asthma is unknown. OBJECTIVE To determine whether asthma is associated with changes in the local and systemic expression of 90K protein and whether 90K protein affects the TH2 cytokine profile that is a hallmark of asthma. METHODS The 90K protein levels were measured in the systemic circulation of 69 individuals with asthma and 68 controls and in the bronchoalveolar lavage fluid of 9 controls and 7 atopic asthmatic patients before and after segmental allergen challenge. The effects of 90K protein on interleukin 4 (IL-4), IL-5, IL-13, and IL-6 production at protein and transcriptional levels in cultured human peripheral blood mononuclear cells were determined. RESULTS Plasma concentrations of 90K protein were higher in asthmatic individuals vs controls (P = .002), were higher in the bronchoalveolar lavage fluid of asthmatic patients vs controls (P < .01), and increased after segmental allergen challenge in atopic asthmatic patients (P < .03). Increasing concentrations of 90K protein resulted in significantly reduced IL-4, IL-5, and IL-13 concentrations and increased IL-6 concentrations in the supernatants of cultured peripheral blood mononuclear cells (P < .05). Reverse transcriptase-polymerase chain reaction studies showed parallel changes in the transcription of these cytokines. CONCLUSIONS Local and systemic concentrations of 90K protein are increased in asthma. Its inhibitory effect on TH2 cytokine transcription suggests that increased 90K protein expression is an attempt to limit the ongoing inflammation in asthma.