The Roles of MicroRNAs in Asthma and Emerging Insights into the Effects of Vitamin D3 Supplementation

Asthma is one of the most common chronic non-communicable diseases worldwide, characterized by variable airflow limitation secondary to airway narrowing, airway wall thickening, and increased mucus resulting from chronic inflammation and airway remodeling. Current epidemiological studies reported that hypovitaminosis D is frequent in patients with asthma and is associated with worsening the disease and that supplementation with vitamin D3 improves asthma symptoms. However, despite several advances in the field, the molecular mechanisms of asthma have yet to be comprehensively understood. MicroRNAs play an important role in controlling several biological processes and their deregulation is implicated in diverse diseases, including asthma. Evidence supports that the dysregulation of miR-21, miR-27b, miR-145, miR-146a, and miR-155 leads to disbalance of Th1/Th2 cells, inflammation, and airway remodeling, resulting in exacerbation of asthma. This review addresses how these molecular mechanisms explain the development of asthma and its exacerbation and how vitamin D3 may modulate these microRNAs to improve asthma symptoms.

Advances in the Relationship between Respiratory Viruses and Asthma

Several studies have reported that viral infection is closely associated with the onset, progression, and exacerbation of asthma. The purpose of this review is to summarize the role that viral infections have in the pathogenesis of asthma onset and exacerbations, as well as discuss interrelated protective and risk factors of asthma and current treatment options. Furthermore, we present current knowledge of the innate immunological pathways driving host defense, including changes in the epithelial barrier. In addition, we highlight the importance of the genetics and epigenetics of asthma and virus susceptibility. Moreover, the involvement of virus etiology from bronchiolitis and childhood wheezing to asthma is described. The characterization and mechanisms of action of the respiratory viruses most frequently related to asthma are mentioned.

Early Prediction of Asthma

The clinical manifestations of asthma in children are highly variable, are associated with different molecular and cellular mechanisms, and are characterized by common symptoms that may diversify in frequency and intensity throughout life. It is a disease that generally begins in the first five years of life, and it is essential to promptly identify patients at high risk of developing asthma by using different prediction models. The aim of this review regarding the early prediction of asthma is to summarize predictive factors for the course of asthma, including lung function, allergic comorbidity, and relevant data from the patient's medical history, among other factors. This review also highlights the epigenetic factors that are involved, such as DNA methylation and asthma risk, microRNA expression, and histone modification. The different tools that have been developed in recent years for use in asthma prediction, including machine learning approaches, are presented and compared. In this review, emphasis is placed on molecular mechanisms and biomarkers that can be used as predictors of asthma in children.

Effect of Obesity on Lung Function in the Pediatric and Adult Populations with Asthma: A Review

Obesity and asthma are major global health concerns, particularly in industrialized nations. Obesity has been shown to have detrimental effects on the respiratory system and lung function owing to metabolic issues and immunological consequences. Research has indicated that obese patients with asthma (atopic or T2-high and non-atopic or T2-low) have diminished lung function in terms of functional residual capacity (FRC), residual volume (RV), expiratory reserve volume (ERV), the FEV1/FVC ratio, and FEF 25-75% due to mechanical fat loading on the diaphragm and central adiposity when compared to non-obese asthmatic patients. Therefore, it is plausible that changes in lung function are the result of a combination of mechanical (fat loading on the diaphragm, central adiposity, bronchial hyper-reactivity, and an increase in cholinergic tone), environmental (diet and exercise), and inflammatory factors (local and systemic), which can lead to the obesity-related asthma phenotype characterized by severe asthma symptoms, poor response to corticosteroid treatment, loss of lung function, and poor quality of life from an early age.

Whole Blood Expression Levels of Long Noncoding RNAs: HOTAIRM1, GAS5, MZF1-AS1, and OIP5-AS1 as Biomarkers in Adolescents with Obesity-Related Asthma

Asthma is a heterogeneous entity encompassing distinct endotypes and varying phenotypes, characterized by common clinical manifestations, such as shortness of breath, wheezing, and variable airflow obstruction. Two major asthma endotypes based on molecular patterns are described: type 2 endotype (allergic-asthma) and T2 low endotype (obesity-related asthma). Long noncoding RNAs (lncRNAs) are transcripts of more than 200 nucleotides in length, currently involved in many diverse biological functions, such as chromatin remodeling, gene transcription, protein transport, and microRNA processing. Despite the efforts to accurately classify and discriminate all the asthma endotypes and phenotypes, if long noncoding RNAs could play a role as biomarkers in allergic asthmatic and adolescent obesity-related asthma, adolescents remain unknown. To compare expression levels of lncRNAs: HOTAIRM1, OIP5-AS1, MZF1-AS1, and GAS5 from whole blood of Healthy Adolescents (HA), Obese adolescents (O), allergic asthmatic adolescents (AA) and Obesity-related asthma adolescents (OA). We measured and compared expression levels from the whole blood of the groups mentioned above through RT-q-PCR. We found differentially expressed levels of these lncRNAs between the groups of interest. In addition, we found a discriminative value of previously mentioned lncRNAs between studied groups. Finally, we generated an interaction network through bioinformatics. Expression levels of OIP5-AS1, MZF1-AS1, HOTAIRM1, and GAS5 in whole blood from the healthy adolescent population, obese adolescents, allergic asthma adolescents, and obesity-related asthma adolescents are differently expressed. Moreover, these lncRNAs could act as molecular biomarkers that help to discriminate between all studied groups, probably through molecular mechanisms with several genes and miRNAs implicated.

Asthma management and control in children, adolescents, and adults in 25 countries: a Global Asthma Network Phase I cross-sectional study

BACKGROUND

Asthma is one of the most common non-communicable diseases globally. This study aimed to assess asthma medicine use, management plan availability, and disease control in childhood, adolescence, and adulthood across different country settings.

METHODS

We used data from the Global Asthma Network Phase I cross-sectional epidemiological study (2015-20). A validated, written questionnaire was distributed via schools to three age groups (children, 6-7 years; adolescents, 13-14 years; and adults, ≥19 years). Eligible adults were the parents or guardians of children and adolescents included in the surveys. In individuals with asthma diagnosed by a doctor, we collated responses on past-year asthma medicines use (type of inhaled or oral medicine, and frequency of use). Questions on asthma symptoms and health visits were used to define past-year symptom severity and extent of asthma control. Income categories for countries based on gross national income per capita followed the 2020 World Bank classification. Proportions (and 95% CI clustered by centre) were used to describe results. Generalised structural equation multilevel models were used to assess factors associated with receiving medicines and having poorly controlled asthma in each age group.

FINDINGS

Overall, 453 473 individuals from 63 centres in 25 countries were included, comprising 101 777 children (6445 [6·3%] with asthma diagnosed by a doctor), 157 784 adolescents (12 532 [7·9%]), and 193 912 adults (6677 [3·4%]). Use of asthma medicines varied by symptom severity and country income category. The most used medicines in the previous year were inhaled short-acting β2 agonists (SABA; range across age groups, 29·3-85·3% participants) and inhaled corticosteroids (12·6-51·9%). The proportion of individuals with severe asthma symptoms not taking inhaled corticosteroids (inhaled corticosteroids alone or with long-acting β2 agonists) was high in all age groups (934 [44·8%] of 2085 children, 2011 [60·1%] of 3345 adolescents, and 1142 [55·5%] of 2058 adults), and was significantly higher in middle-to-low-income countries. Oral SABA and theophylline were used across age groups and country income categories, contrary to current guidelines. Asthma management plans were used by 4049 (62·8%) children, 6694 (53·4%) adolescents, and 3168 (47·4%) adults; and 2840 (44·1%) children, 6942 (55·4%) adolescents, and 4081 (61·1%) adults had well controlled asthma. Independently of country income and asthma severity, having an asthma management plan was significantly associated with the use of any type of inhaled medicine (adjusted odds ratio [OR] 2·75 [95% CI 2·40-3·15] for children; 2·45 [2·25-2·67] for adolescents; and 2·75 [2·38-3·16] for adults) or any type of oral medicine (1·86 [1·63-2·12] for children; 1·53 [1·40-1·68] for adolescents; and 1·78 [1·55-2·04] for adults). Poor asthma control was associated with low country income (lower-middle-income and low-income countries vs high-income countries, adjusted OR 2·33 [95% CI 1·32-4·14] for children; 3·46 [1·83-6·54] for adolescents; and 4·86 [2·55-9·26] for adults).

INTERPRETATION

Asthma management and control is frequently inadequate, particularly in low-resource settings. Strategies should be implemented to improve adherence to asthma treatment guidelines worldwide, with emphasis on access to affordable and quality-assured essential asthma medicines especially in low-income and middle-income countries.

FUNDING

International Union Against Tuberculosis and Lung Disease, Boehringer Ingelheim New Zealand, AstraZeneca, UK National Institute for Health Research, UK Medical Research Council, European Research Council, the Spanish Instituto de Salud Carlos III.

TRANSLATION

For the Spanish translation of the abstract see Supplementary Materials section.

Promoter methylation status of RORC, IL17A, and TNFA in peripheral blood leukocytes in adolescents with obesity-related asthma

A higher Th17-immune response characterises obesity and obesity-related asthma phenotype. Nevertheless, obesity-related asthma has a more significant Th17-immune response than obesity alone. Retinoid-related orphan receptor C (RORC) is the essential transcription factor for Th17 polarisation. Previous studies have found that adolescents with obesity-related asthma presented upregulation of RORC, IL17A, and TNFA. However, the mechanisms that cause these higher mRNA expression levels in this asthmatic phenotype are poorly understood. Methylation directly regulates gene expression by adding a methyl group to carbon 5 of dinucleotide CpG cytosine. Thus, we evaluated the relationship between RORC, IL17A, and TNFA methylation status and mRNA expression levels to investigate a possible epigenetic regulation. A total of 102 adolescents (11-18 years) were studied in the following four groups: 1) healthy participants (HP), 2) allergic asthmatic participants (AAP), 3) obese participants without asthma (OP), and 4) non-allergic obesity-related asthma participants (OAP). Real-time qPCR assessed the methylation status and gene expression levels in peripheral blood leukocytes. Remarkably, the OAP and AAP groups have lower promoter methylation patterns of RORC, IL17A, and TNFA than the HP group. Notably, the OAP group presents lower RORC promoter methylation status than the OP group. Interestingly, RORC promoter methylation status was moderately negatively associated with gene expression of RORC (r _s = -0.39, p < 0.001) and IL17A (r _s = -0.37, p < 0.01), respectively. Similarly, the promoter methylation pattern of IL17A was moderately negatively correlated with IL17A gene expression (r _s = -0.3, p < 0.01). There is also a moderate inverse relationship between TNFA promoter methylation status and TNFA gene expression (r _s = -0.3, p < 0.01). The present study suggests an association between lower RORC, IL17A, and TNFA gene promoter methylation status with obesity-related asthma and allergic asthma. RORC, IL17A, and TNFA gene promoter methylation patterns are moderately inversely correlated with their respective mRNA expression levels. Therefore, DNA methylation may regulate RORC, IL17A, and TNF gene expression in both asthmatic phenotypes.

Genome-Wide Association Study Identifies a Functional SIDT2 Variant Associated With HDL-C (High-Density Lipoprotein Cholesterol) Levels and Premature Coronary Artery Disease

Objective

Low HDL-C (high-density lipoprotein cholesterol) is the most frequent dyslipidemia in Mexicans, but few studies have examined the underlying genetic basis. Our purpose was to identify genetic variants associated with HDL-C levels and cardiovascular risk in the Mexican population.

Approach and Results

A genome-wide association studies for HDL-C levels in 2335 Mexicans, identified four loci associated with genome-wide significance: CETP, ABCA1, LIPC, and SIDT2. The SIDT2 missense Val636Ile variant was associated with HDL-C levels and was replicated in 3 independent cohorts (P=5.9×10−18 in the conjoint analysis). The SIDT2/Val636Ile variant is more frequent in Native American and derived populations than in other ethnic groups. This variant was also associated with increased ApoA1 and glycerophospholipid serum levels, decreased LDL-C (low-density lipoprotein cholesterol) and ApoB levels, and a lower risk of premature CAD. Because SIDT2 was previously identified as a protein involved in sterol transport, we tested whether the SIDT2/Ile636 protein affected this function using an in vitro site-directed mutagenesis approach. The SIDT2/Ile636 protein showed increased uptake of the cholesterol analog dehydroergosterol, suggesting this variant affects function. Finally, liver transcriptome data from humans and the Hybrid Mouse Diversity Panel are consistent with the involvement of SIDT2 in lipid and lipoprotein metabolism.

Conclusions

This is the first genome-wide association study for HDL-C levels seeking associations with coronary artery disease in the Mexican population. Our findings provide new insight into the genetic architecture of HDL-C and highlight SIDT2 as a new player in cholesterol and lipoprotein metabolism in humans.

Associations of TNFA, IL17A, and RORC mRNA expression levels in peripheral blood leukocytes with obesity-related asthma in adolescents

Obesity is associated with a unique non-T2 asthma phenotype, characterised by a Th17 immune response. Retinoid-related orphan receptor C (RORC) is the master transcription factor for Th17 polarisation. We investigated the association of TNFA, IL17A, and RORC mRNA expression levels with the non-T2 phenotype. We conducted a cross-sectional study in adolescents, subdivided as follows: healthy (HA), allergic asthma without obesity (AA), obesity without asthma (OB), and non-allergic asthma with obesity (NAO). TNFA, IL17A, and RORC mRNA expression in peripheral blood leukocytes were assessed by RT-PCR. NAO exhibited higher TNFA mRNA expression levels than HA or OB, as well as the highest IL17A and RORC mRNA expression levels among the four groups. The best biomarker for discriminating non-allergic asthma among obese adolescents was RORC mRNA expression levels (area under the curve: 0.95). RORC mRNA expression levels were associated with the non-T2 asthma phenotype, hinting at a therapeutic target in obesity-related asthma.

Compromising between European and US allergen immunotherapy schools: Discussions from GUIMIT, the Mexican immunotherapy guidelines

Background

Allergen immunotherapy (AIT) has a longstanding history and still remains the only disease-changing treatment for allergic rhinitis and asthma. Over the years 2 different schools have developed their strategies: the United States (US) and the European. Allergen extracts available in these regions are adapted to local practice. In other parts of the world, extracts from both regions and local ones are commercialized, as in Mexico. Here, local experts developed a national AIT guideline (GUIMIT 2019) searching for compromises between both schools.

Methods

Using ADAPTE methodology for transculturizing guidelines and AGREE-II for evaluating guideline quality, GUIMIT selected 3 high-quality Main Reference Guidelines (MRGs): the European Academy of Allergy, Asthma and Immunology (EAACI) guideines, the S2k guideline of various German-speaking medical societies (2014), and the US Practice Parameters on Allergen Immunotherapy 2011. We formulated clinical questions and based responses on the fused evidence available in the MRGs, combined with local possibilities, patient's preference, and costs. We came across several issues on which the MRGs disagreed. These are presented here along with arguments of GUIMIT members to resolve them. GUIMIT (for a complete English version, Supplementary data) concluded the following.

Results

Related to the diagnosis of IgE-mediated respiratory allergy, apart from skin prick testing complementary tests (challenges, in vitro testing and molecular such as species-specific allergens) might be useful in selected cases to inform AIT composition. AIT is indicated in allergic rhinitis and suggested in allergic asthma (once controlled) and IgE-mediated atopic dermatitis. Concerning the correct subcutaneous AIT dose for compounding vials according to the US school: dosing tables and formula are given; up to 4 non-related allergens can be mixed, refraining from mixing high with low protease extracts. When using European extracts: the manufacturer's indications should be followed; in multi-allergic patients 2 simultaneous injections can be given (100% consensus); mixing is discouraged. In Mexico only allergoid tablets are available; based on doses used in all sublingual immunotherapy (SLIT) publications referenced in MRGs, GUIMIT suggests a probable effective dose related to subcutaneous immunotherapy (SCIT) might be: 50-200% of the monthly SCIT dose given daily, maximum mixing 4 allergens. Also, a table with practical suggestions on non-evidence-existing issues, developed with a simplified Delphi method, is added. Finally, dissemination and implementation of guidelines is briefly discussed, explaining how we used online tools for this in Mexico.

Conclusions

Countries where European and American AIT extracts are available should adjust AIT according to which school is followed.

IL-17A and TNF-α as potential biomarkers for acute respiratory distress syndrome and mortality in patients with obesity and COVID-19

Coronavirus disease 2019 (COVID-19) was declared a pandemic and international health emergency by the World Health Organization. Patients with obesity with COVID-19 are 7 times more likely to need invasive mechanical ventilation than are patients without obesity (OR 7.36; 95% CI: 1.63–33.14, p = 0.021). Acute respiratory distress syndrome (ARDS) is one of the main causes of death related to COVID-19 and is triggered by a cytokine storm that damages the respiratory epithelium. Interleukins that cause the chronic low-grade inflammatory state of obesity, such as interleukin (IL)-1β, IL-6, monocyte chemoattractant peptide (MCP)-1, and, in particular, IL-17A and tumour necrosis factor alpha (TNF-α), also play very important roles in lung damage in ARDS. Therefore, obesity is associated with an immune state favourable to a cytokine storm. Our hypothesis is that serum concentrations of TNF-α and IL-17A are more elevated in patients with obesity and COVID-19, and consequently, they have a greater probability of developing ARDS and death. The immunobiology of IL-17A and TNF-α opens a new fascinating field of research for COVID-19.

Asma: uso adecuado de dispositivos para inhalación

Inhaled therapy is considered the cornerstone of asthma treatment. However, despite being the ideal form of drug delivery, it is recognized that only 70% of patients have an adequate attachment to their treatment and only 39-67% of physicians can explain the optimal inhaler technique. Inhaled therapy has very specific characteristics. Pulmonary deposit of an inhaled medication through the respiratory tract is more complex than when administered orally and depends on several factors inherent to both the medication and the administration. For successful inhaled therapy, the drug needs to be converted into particles of an appropriate size, which can enter beyond the oropharynx and larynx, and be deposited in the lungs. There are multiple devices for the administration of drugs in the lower respiratory tract, each one with a similar efficacy as long as it is used with the correct technique. The decision of which device should be used is made based on the age of the patient, the ability to coordinate between the inhalation and activation of the device, and the presence of acute symptoms. The choice of the device must be evaluated individually.

Decreased methylation profiles in the TNFA gene promoters in type 1 macrophages and in the IL17A and RORC gene promoters in Th17 lymphocytes have a causal association with non-atopic asthma caused by obesity: A hypothesis

Obesity is a serious public health problem worldwide and has been associated in epidemiological studies with a unique type of non-atopic asthma, although the causal association of asthma and obesity has certain criteria, such as the strength of association, consistency, specificity, temporality, biological gradient, coherence, analogy and experimentation; nevertheless, the biological plausibility of this association remains uncertain. Various mechanisms have been postulated, such as immunological, hormonal, mechanical, environmental, genetic and epigenetic mechanisms. Our hypothesis favours immunological mechanisms because some cytokines, such as tumour necrosis factor alpha (TNF-α) and interleukin (IL)-17A, are responsible for orchestrating low-grade systemic inflammation associated with obesity; however, these cytokines are regulated by epigenetic mechanisms, such as gene promoter methylation.

Effect of supplementation with omega-3 fatty acids on hypertriglyceridemia in pediatric patients with obesity

Background The beneficial effects of treating hypertriglyceridemic adults with omega-3 fatty acids have been reported. However, information regarding omega-3 treatment of pediatric patients is limited. To evaluate the efficacy and safety of administering omega-3 fatty acids (3 g/day for 12 weeks) to children/adolescents with obesity and hypertriglyceridemia. Methods A randomized, double-blind, placebo-controlled, parallel study involving pediatric patients (10-16 years old) with obesity and hypertriglyceridemia was conducted. The National Center for Health Statistics (CDC) defines obesity as a body mass index (BMI) ≥95th percentile. Subjects with triglyceride concentrations ranging from 150 to 1000 mg/dL were randomized into two groups: those receiving omega-3 fatty acids (eicosapentaenoic and docosahexaenoic acids) (n = 65) and those receiving a placebo (n = 65) for 12 weeks. Serum triglyceride concentrations were always measured from 8 to 9 am after a 12-h fast. Results By the end of treatment, triglyceride concentrations had decreased by 39.1% in the omega-3 group and 14.6% in the placebo group (p < 0.01). The incidence of adverse gastrointestinal events (e.g. flatulence, belching) was 41.2% and 6.2% in the omega-3 and placebo groups, respectively (p < 0.01). There were no serious drug-related adverse events. Conclusions Supplementation with 3 g/day of omega-3 fatty acids is a safe and effective option for treating hypertriglyceridemia in children and adolescents with obesity.

An Amino Acid Signature Associated with Obesity Predicts 2-Year Risk of Hypertriglyceridemia in School-Age Children

Childhood obesity is associated with a number of metabolic abnormalities leading to increased cardiovascular risk. Metabolites can be useful as early biomarkers and new targets to promote early intervention beginning in school age. Thus, we aimed to identify metabolomic profiles associated with obesity and obesity-related metabolic traits. We used data from the Obesity Research Study for Mexican children (ORSMEC) in Mexico City and included a case control (n = 1120), cross-sectional (n = 554) and a longitudinal study (n = 301) of 6-12-year-old children. Forty-two metabolites were measured using electrospray MS/MS and multivariate regression models were used to test associations of metabolomic profiles with anthropometric, clinical and biochemical parameters. Principal component analysis showed a serum amino acid signature composed of arginine, leucine/isoleucine, phenylalanine, tyrosine, valine and proline significantly associated with obesity (OR = 1.57; 95%CI 1.45-1.69, P = 3.84 × 10-31) and serum triglycerides (TG) (β = 0.067, P = 4.5 × 10-21). These associations were validated in the cross-sectional study (P < 0.0001). In the longitudinal cohort, the amino acid signature was associated with serum TG and with the risk of hypertriglyceridemia after 2 years (OR = 1.19; 95%CI 1.03-1.39, P = 0.016). This study shows that an amino acid signature significantly associated with childhood obesity, is an independent risk factor of future hypertriglyceridemia in children.

The consumption of n-3 polyunsaturated fatty acids differentially modulates gene expression of peroxisome proliferator-activated receptor alpha and gamma and hypoxia-inducible factor 1 alpha in subcutaneous adipose tissue of obese adolescents

The aim of this study was to evaluate the effect of long-chain omega-3 polyunsaturated fatty acid (n-3 PUFA) supplementation on metabolic state and gene expression in subcutaneous adipose tissues of obese adolescents. Obese adolescents (n = 26, 10 girls and 16 boys) aged 12.4 ± 2.1 years were assigned to a 12-week regimen of n-3 PUFA intake. Five times per day, subjects received a food supplement consisting of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) (3 g per day, 944 mg EPA, and 2,088 mg DHA). Blood parameters were measured, and subcutaneous adipose tissue biopsies were analyzed to determine gene expression at baseline and after 12 weeks. Student's t test and the Wilcoxon signed-rank test were used to estimate differences in arithmetic means of pre- and post-dietary supplementation for various anthropometric, biochemical, clinical, and gene expression parameters. After 12 weeks, n-3 PUFA consumption was associated with decreased body mass index (29.7 ± 4.6 vs. 27.8 ± 4.4 kg/m(2); P < 0.001), waist circumference (93.2 ± 9.9 vs. 90.5 ± 10.0 cm; P < 0.003), hip circumference (102.9 ± 10.9 vs. 101.1 ± 10.9 cm; P < 0.014), and blood triglyceride levels (220.8 ± 27.4 vs. 99.7 ± 32.7 mg/dL; P < 0.001). Fatty acid supplementation/n3 PUFA supplementation was associated with a downregulated expression of the genes encoding PPARγ and PGC-1α (P < 0.001), and an upregulated expression of the genes encoding PPARα (P < 0.007) and SREBP1 (P < 0.021). The expressions of SOD2 (P < 0.04), CAT (P < 0.001), GPX3 (P < 0.032) and HIF-1α protein also decreased. Our study demonstrated that n-3 PUFA consumption and dietary restriction improved the anthropometric parameters and decreased the triglycerides levels of the adolescents, suggesting a reduction in hypoxia in subcutaneous adipose tissue.

NFE2L2 gene variants and susceptibility to childhood-onset asthma

INTRODUCTION

Environmental factors causing oxidative stress are known to be associated with asthma morbidity. The antioxidative gene NFE2L2 has been implicated in asthma development in mice models. In humans, the SNPs -617C/A and -653G/A, located at the promoter region of NFE2L2 gene, have been found associated with the susceptibility to develop diverse chronic-degenerative diseases.

OBJECTIVE

To determine if there is association of the -617C/A and -653G/A NFE2L2 SNPs and childhood-onset asthma in a Mexican population.

MATERIALS AND METHODS

In a case-control study 242 unrelated patients with diagnosis of asthma and 358 ethnically- and sex-matched healthy individuals were included. The -617C/A and -653G/A NFE2L2 genotyping was carried out using the TaqMan allelic discrimination assay.

RESULTS

The risk allele of both polymorphisms showed a high frequency in our sample (-617A: 24% and -653A: 40%), similarly to those previously reported in Asiatic populations (-617A: 24-29% and -653A: 42-52%; p > 0.05). In contrast, the -617A allele frequency was higher than that reported in a European-African admixed population (10%, p < 0.001). The allelic and genotypic frequencies from both polymorphisms showed no significant differences among cases and controls in female and male samples. Likewise, haplotype analysis found no association between NFE2L2 gene variants and the disease.

CONCLUSIONS

Despite the experimental evidence suggesting that NFE2L2 gene is involved in asthma pathogenesis, the -617C/A and -653G/A SNPs were not associated with childhood-onset asthma.

Factors associated with allergic rhinitis in children from northern Mexico City

BACKGROUND

The International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire allows users to find factors associated with allergic diseases, but thus far most of the studies on risk factors for allergic diseases have been devoted to asthma and not to rhinitis.

OBJECTIVE

To determine the main factors associated with symptoms of allergic rhinitis and rhinoconjunctivitis in school children and adolescents in northern Mexico City.

PATIENTS AND METHODS

A cross sectional, multicenter survey was conducted in northern Mexico City, in children aged 6-7 and 13-14 years. The survey instrument was the Phase Three B ISAAC questionnaire, which was validated and standardized in Spanish.

RESULTS

There were 4106 6-7-year-olds and 6576 13-14-year-olds. The total prevalence of diagnosis of allergic rhinitis was 4.6%. The prevalence of cumulative and current symptoms of rhinitis was considered high (>29%), but the prevalence of the diagnosis of allergic rhinitis was considered low (ranging from 3.4% to 5.6%). The prevalence of symptoms of rhinitis with conjunctivitis had intermediate values (ranging from 20.3% to 30.2%). Cumulative symptoms of allergic rhinitis, current symptoms of allergic rhinitis, and rhinoconjunctivitis were related to symptoms of current or cumulative asthma, symptoms of current or cumulative atopic eczema, and current use of paracetamol (odds ratio > 1, P < .05).

CONCLUSION

The present results support the concept of rhinitis and asthma as common chronic respiratory diseases, and this study also found a relation between paracetamol use and rhinitis in children.

Use of OM-85 BV in children suffering from recurrent respiratory tract infections and subnormal IgG subclass levels

BACKGROUND

Recurrent acute respiratory tract infections (RARTIs) in children are related to IgG subclass deficiencies. The aim of the trial was to evaluate the effect of OM-85 BV in the number of RARTIs as well as in the IgG subclass levels.

METHODS

This was a randomized, double-blind, placebo-controlled clinical trial. Patients of ages three to six years, having three or more documented ARTIs during the last six months with subnormal IgG subclass levels were included. Patients took either one capsule of OM-85 BV (3.5 mg) or placebo orally every day for ten consecutive days per month during three consecutive months. Patients were followed three further months without drug intake. IgG subclass levels were determined before and after treatment.

RESULTS

IgG4 levels diminished after the OM-85 BV treatment (-3 [-8.0, -1.0] median difference [95 % CI] p < 0.05 by Wilcoxon test). No other significant changes in IgG subclasses were observed. After six months the patients in the OM-85 BV group (n = 20) experienced 2.8 1.4 (mean SD) ARTIs, while the patients in the placebo group (n = 20) suffered 5.2 1.5 ARTIs (-2.4 [3.3, -1.5] mean difference [95 % CI] p < 0.001 by Student's t test). Three patients with OM-85 BV had gastrointestinal events related to drug administration, as well as three placebo patients.

CONCLUSION

This study demonstrated the clinical benefit of OM-85 BV in patients suffering from RARTIs and subnormal levels of IgG subclasses. This trial opens new perspectives in the research of the mechanism of action of OM-85 BV.