Atopic and nonatopic asthma in children

Polymorphisms in recent GWA identified asthma genes CA10, SGK493, and CTNNA3 are associated with disease severity and treatment response in childhood asthma

Recent genome-wide association studies (GWAs) have identified several new genetic risk factors for asthma; however, their influence on disease behavior and treatment response is still unclear. The aim of our study was the association analysis of the most significant single nucleotide polymorphisms (SNPs) recently reported by GWAs in different phenotypes of childhood asthma and analysis of correlation between these SNPs and clinical parameters. We have genotyped 288 children with asthma and 276 healthy controls. We provided here first replication of bivariate associations between CA10 (p = 0.001) and SGK493 (p = 0.011) with asthma. In addition, we have identified new correlation between SNPs in CA10, SGK493, and CTNNA3 with asthma behavior and glucocorticoid treatment response. Asthma patients who carried G allele in SNP rs967676 in gene CA10 were associated with more pronounced airway obstruction, higher bronchial hyper-reactivity, and increased inflammation. Higher bronchial hyper-reactivity was also associated with C allele in SNP rs1440095 in gene SGK493 but only in nonatopic asthmatics. In addition, we found that patients who carried at least one T allele in SNP rs1786929 in CTNNA3 (p = 0.022) and atopic patients who carried at least one G allele in SNP rs967676 in gene CA10 (p = 0.034) had higher increase in pulmonary function after glucocorticoid therapy. Our results suggest genetic heterogeneity between atopic and nonatopic asthma. We provided further evidence that treatment response in childhood asthma is genetically predisposed, and we report here two novel SNPs in genes CA10 and CTNNA3 as potential pharmacogenetic biomarkers that could be used in personalized treatment in childhood asthma.

Persistent pulmonary function impairment in children and adolescents with asthma

OBJECTIVE

Asthma is the most common chronic pulmonary disease, characterized by bronchial inflammation. Some children with asthma have persistent pulmonary function impairment. The prevalence and etiology of this abnormality in children with asthma in developing countries remain unknown. The objective of this study was to estimate the proportion of patients with impaired pulmonary function who were unresponsive to treatment in a group of children and adolescents with asthma, and to describe the phenotypic characteristics of the sample.

METHODS

Using a standardized questionnaire, we selected outpatients (5-17 years of age) diagnosed with persistent asthma. These patients underwent spirometry and skin prick tests for sensitivity to common aeroallergens. Persistent pulmonary function impairment was defined as an FEV1/FVC ratio < 0.80, even after 10 days of treatment with bronchodilators and oral corticosteroids. We used the atopic index to differentiate between patients with little or no response to the skin prick test and those with a strong response (cut-off point: 4 allergens).

RESULTS

We included 96 patients with a mean age of 10.6 years. Of those, 52 (54.1%) were male, and 89 (92.7%) were atopic. Of the 96 patients, 8 (8.3%) had impaired pulmonary function even after the treatment. Among those patients, 8 (100%) were atopic, 7 (87.5%) had moderate or severe asthma, and 7 (87.5%) had a history of hospitalization for acute bronchiolitis.

CONCLUSIONS

Children and adolescents with moderate or severe asthma can present with impaired pulmonary function and be unresponsive to treatment. This clinical situation has been little studied in developing countries, and its risk factors and etiology will be better understood only through birth cohort studies.

Clinical, functional, and epidemiological differences between atopic and nonatopic asthmatic children from a tertiary care hospital in a developing country

BACKGROUND

Differences between children with atopic asthma (AA) and nonatopic asthma (non-AA) have been shown in epidemiologic studies. In developing countries, even when non-AA is more prevalent than AA among schoolchildren, no data are available regarding clinical, functional, and epidemiological differences between these 2 groups.

OBJECTIVE

To evaluate differences between Chilean children with AA and non-AA.

METHODS

In this cross-sectional study, skin prick tests were performed on all patients (age range, 4-14 years) admitted to our tertiary care hospital with the diagnosis of asthma who were consequently classified as having AA or non-AA. Demographic characteristics, spirometry results, exercise bronchial challenge test results, and eosinophil counts measured in the last 12 months were recorded.

RESULTS

Among the 237 asthmatic children, 62.5% had AA. Non-AA children had a significantly earlier onset of asthma and a more frequent history of pneumonia and tobacco consumption at home. Children with AA had higher nasal eosinophilia levels and a higher prevalence of dermatitis and severe exacerbation episodes of asthma in the past year (emergency department consultation and oral corticosteroids courses). Lung function was similar in both groups. After the multivariate analysis, only the number of oral steroid courses was significantly different between the groups and was associated with AA.

CONCLUSIONS

In this selected population of asthmatic schoolchildren, the prevalence of non-AA (37.6%) is not negligible, and some differences between AA and non-AA children exist.