Vojko Berce

Association of Q551R polymorphism in the interleukin 4 receptor gene with nonatopic asthma in Slovenian children

SummaryBACKGROUND: Asthma is one of the most common chronic diseases of childhood and results from the interaction of several genes and environmental influences. Interleukin 4 (IL4) and its receptor IL4R have a central role in the regulation of immunoglobulin E (IgE) production and thereby in the induction and maintenance of allergy and asthma. The single nucleotide polymorphisms (SNPs) Q551R in the IL4RA gene and C-33T in the IL4 gene probably influence IL4/IL4R pathway signaling; however, findings in association studies exploring the role of these two genes in asthma pathogenesis are contradictory. We have studied the association of IL4RA Q551R and IL4 C-33T SNPs with asthma, asthma phenotypes, and clinical and laboratory parameters. METHODS: The study group comprised 106 children aged between 5 and 18 years with mild or moderate persistent asthma: 78 children were atopic and 28 had nonatopic asthma. The children underwent allergy and spirometry tests, a bronchoprovocation test with methacholine, measurement of exhaled nitric oxide in expired air and genotyping for IL4RA Q551R and IL4 C-33T SNPs. Genotype data from 89 nonatopic nonasthmatics served as a control group. RESULTS: The frequency of the IL4RA Arg551 allele in the children with nonatopic asthma was 7.1%, significantly lower than 21.9% in the control group (P = 0.01, OR: 0.33, 95% CI: 0.12–0.87). Allelic and genotype frequencies in IL4 C-33T polymorphism in the asthma group and the control group were not significantly different. The mean value of total IgE in asthmatics with the IL4-33C allele was 556.0 IU/l, significantly higher than 371.6 IU/l in those with the T allele (P = 0.02). In an interaction study we did not find significant differences in the frequencies of any combinations of IL4RA Q551R and IL4 C-33T alleles between asthmatics and controls. CONCLUSIONS: The IL4RA Q551R SNP is associated with nonatopic asthma in Slovenian children. This finding contributes to knowledge about an important asthma phenotype pathogenesis and could serve in future research into new strategies for asthma management.

CD14 gene polymorphism is not associated with asthma but rather with bronchial obstruction and hyperreactivity in Slovenian children with non-atopic asthma

BACKGROUND Though the associations of CD14 with asthma have already been studied, the results of different independent studies are in conflict, mostly due to differences in the pathogenesis of varying asthma sub-phenotypes. The aim of our study was to perform an association analysis of promoter single nucleotide polymorphism (SNP) -159C/T (rs2569190) in the CD14 gene for Slovenian children with asthma. METHODS We analyzed SNP -159C/T in a group of all asthmatics, and separately in a group of atopic and non-atopic asthmatics. We also analyzed the influence of SNP -159C/T on clinical parameters and the response to therapy with inhaled corticosteroids. We have genotyped 247 children with asthma and a median age of 11 years (interquartile range, 5 years), and 158 healthy controls with a median age of 13 years (interquartile range, 5 years). We performed genotyping using a polymerase chain reaction (PCR) followed by restriction fragment length polymorphism (RFLP) analysis. RESULTS We found that SNP -159C/T in CD14 is not associated with asthma in Slovenian children. However, non-atopic asthmatics with CT or TT genotypes have a lower FEV1/FVC ratio as a measure of bronchial obstruction (87.4%, compared to 91.8% in patients with the CC genotype, p = 0.017). Non-atopic asthmatics with CC or CT genotypes also have increased bronchial hyperreactivity measured by PC20 of methacholine (0.41 mg/ml, compared to 1.50 mg/ml in patients with a TT genotype, p = 0.018). CONCLUSIONS Our results suggest that CD14 is associated with asthma severity in Slovenian children with non-atopic asthma.

Association of CCR5-delta32 Mutation with Reduced Risk of Nonatopic Asthma in Slovenian Children

Asthma is one of the most common chronic diseases of childhood. Asthma results from the interaction of several genes and environmental influences. Viral infections are common triggers of asthma attacks, especially in nonatopic asthmatics. CCR5 is a chemokine receptor involved in the immune response against a number of viruses. A 32 base pair deletion (delta32) in the CCR5 receptor gene causes loss of gene function and is associated with several chronic diseases due to the resulting altered immunity. The results of the association studies exploring the role of the CCR5 receptor gene in asthma pathogenesis are contradictory. We studied 111 children aged between 5 and 18 years with mild or moderate persistent asthma; 75 of them were atopic and 36 had nonatopic asthma. We carried out allergy and spirometry tests, a bronchoprovocation test with methacholine and performed measurement of exhaled nitric oxide and genotyping for CCR5-delta32 mutation. Compared with 365 nonatopic, nonasthmatic controls we found significantly lower CCR5-delta32 allelic frequency in nonatopic asthmatics (p = 0.016, OR 0.139, 95% CI 0.02 to 0.984) but not in atopic asthmatics. CCR5-delta32 mutation protects against nonatopic asthma. This association offers new insights into the pathogenesis of an important asthma phenotype and could serve as useful information for the future research of new asthma management strategies.

Functional polymorphism in CTLA4 gene influences the response to therapy with inhaled corticosteroids in Slovenian children with atopic asthma.

We genotyped CTLA4 CT60 (rs3087243) functional single nucleotide polymorphism (SNP) in children with asthma and in healthy controls and correlated the genotype data with asthma clinical data, including treatment response with inhaled corticosteroids measured by forced expiratory volume in the first second (FEV1). FEV1 increased by 21.7% after 4 weeks of therapy in atopic asthmatics with the A/A genotype compared with an 8.6% increase in heterozygotes and a 5.8% increase in G/G homozygotes (p <0.01). Genotype and allele frequencies in asthmatics did not differ significantly from those in the control group. SNP CT60 in the CTLA4 gene is significantly associated with the response to treatment with inhaled corticosteroids in children with atopic asthma and could be a useful biomarker for personalized therapy in asthmatic children. SNP CT60 in the CTLA4 gene plays only a minor role in genetic susceptibility to childhood asthma in the Caucasian population.

Rationale and design of the multiethnic Pharmacogenomics in Childhood Asthma consortium

AIM International collaboration is needed to enable large-scale pharmacogenomics studies in childhood asthma. Here, we describe the design of the Pharmacogenomics in Childhood Asthma (PiCA) consortium. MATERIALS & METHODS Investigators of each study participating in PiCA provided data on the study characteristics by answering an online questionnaire. RESULTS A total of 21 studies, including 14,227 children/young persons (58% male), from 12 different countries are currently enrolled in the PiCA consortium. Fifty six percent of the patients are Caucasians. In total, 7619 were inhaled corticosteroid users. Among patients from 13 studies with available data on asthma exacerbations, a third reported exacerbations despite inhaled corticosteroid use. In the future pharmacogenomics studies within the consortium, the pharmacogenomics analyses will be performed separately in each center and the results will be meta-analyzed. CONCLUSION PiCA is a valuable platform to perform pharmacogenetics studies within a multiethnic pediatric asthma population.

17q21 variant increases the risk of exacerbations in asthmatic children despite inhaled corticosteroids use.

Approximately 25% of the asthmatic children suffer from uncontrolled asthma despite regular use of inhaled corticosteroids (ICS).1 Variation within the 17q21 locus is the strongest genetic determinant for childhood‐onset asthma.2 Recently, the influence of this locus on treatment outcomes has been shown in several studies.3, 4 The Pharmacogenomics in Childhood Asthma (PiCA) consortium is a multiethnic consortium that brings together data from ≥14 000 asthmatic children/young adults from 12 different countries to study the pharmacogenomics of uncontrolled asthma despite treatment.5 In 14 PiCA populations (with over 4000 asthmatic patients), we studied the association between variation in the 17q21 locus, and asthma exacerbations despite ICS use. We specifically focused on rs7216389, a single nucleotide polymorphism (SNP) in the 17q21 locus strongly associated with childhood asthma and initially identified by Moffatt et al.2 Ten PiCA studies included patients with non‐Hispanic European origins, two included Hispanic patients, one African American, and one included East Asian patients. Additional details of the study populations can be found in the Data S1. Two outcomes were assessed: (i) asthma‐related hospitalizations/emergency department visit (ED) visits and (ii) short courses of oral corticosteroid (OCS) use reported by the parent/child at the study visit or based on completed study questionnaires. Age, gender, genotype data, and exacerbation data were available for 4529 steroid‐treated children and young adults (Table 1). Logistic regression analysis was used to assess the risk of exacerbations when carrying rs7216389. Due to potential heterogeneity between cohorts, the odds ratios (ORs) were meta‐analyzed with the inverse variance weighting method assuming random effects. See Data S1 for more detail.

Ultrasound characteristics of community acquired pneumonia in children

Recent studies showed that the sensitivity of ultrasound for diagnosing pneumonia is at least comparable to chest x-ray. However, little is known about the ultrasound characteristics of different types of pneumonia. Therefore the aim of our study was to evaluate and compare the ultrasound characteristics of lung infiltrates in different types of pneumonia in children. In our prospective study, we included 117 children hospitalized because of community acquired pneumonia, caused by bacteria, viruses and Mycoplasma pneumoniae (atypical pneumonia) in 50, 39 and 28 subjects, respectively. Lung ultrasound was performed in the first 24 hours after admission and the investigation was repeated after 48-72 hours in 105 subjects. Size (largest diameter) and localisation (unilateral/bilateral) of infiltrates were recorded. Lung infiltrates were detected with ultrasound in 115 (98.3%) subjects, compared to 95 (81.2%) subjects with infiltrates seen on chest x-ray (p Chest ultrasound is not only sensitive method for the detection of pneumonia in children, but it can also help in the determination of etiology. However, larger prospective studies are warranted to support our findings.

CTLA4 Expression in Childhood Asthma and the Effect of Treatment with Inhaled Corticosteroid and Leukotriene Receptor Antagonist

Aims: Cytotoxic T lymphocyte antigen 4 (CTLA4), an important regulatory molecule in the process of antigen presentation, was previously associated with the pathogenesis of autoimmune diseases and asthma. Therefore, the goal of our study was to determine the expression of CTLA4 in Original Research Article