Alpha-1 antitrypsin deficiency and Pi*S and Pi*Z SERPINA1 variants are associated with asthma exacerbations

INTRODUCTION AND OBJECTIVES

Asthma is a chronic inflammatory disease of the airways. Asthma patients may experience potentially life-threatening episodic flare-ups, known as exacerbations, which may significantly contribute to the asthma burden. The Pi*S and Pi*Z variants of the SERPINA1 gene, which usually involve alpha-1 antitrypsin (AAT) deficiency, had previously been associated with asthma. The link between AAT deficiency and asthma might be represented by the elastase/antielastase imbalance. However, their role in asthma exacerbations remains unknown. Our objective was to assess whether SERPINA1 genetic variants and reduced AAT protein levels are associated with asthma exacerbations.

MATERIALS AND METHODS

In the discovery analysis, SERPINA1 Pi*S and Pi*Z variants and serum AAT levels were analyzed in 369 subjects from La Palma (Canary Islands, Spain). As replication, genomic data from two studies focused on 525 Spaniards and publicly available data from UK Biobank, FinnGen, and GWAS Catalog (Open Targets Genetics) were analyzed. The associations between SERPINA1 Pi*S and Pi*Z variants and AAT deficiency with asthma exacerbations were analyzed with logistic regression models, including age, sex, and genotype principal components as covariates.

RESULTS

In the discovery, a significant association with asthma exacerbations was found for both Pi*S (odds ratio [OR]=2.38, 95% confidence interval [CI]= 1.40-4.04, p-value=0.001) and Pi*Z (OR=3.49, 95%CI=1.55-7.85, p-value=0.003)Likewise, AAT deficiency was associated with a higher risk for asthma exacerbations (OR=5.18, 95%CI=1.58-16.92, p-value=0.007) as well as AAT protein levels (OR= 0.72, 95%CI=0.57-0.91, p-value=0.005). The Pi*Z association with exacerbations was replicated in samples from Spaniards with two generations of Canary Islander origin (OR=3.79, p-value=0.028), and a significant association with asthma hospitalizations was found in the Finnish population (OR=1.12, p-value=0.007).

CONCLUSIONS

AAT deficiency could be a potential therapeutic target for asthma exacerbations in specific populations.

Admixture mapping of severe asthma exacerbations in Hispanic/Latino children and youth

BACKGROUND

In the USA, genetically admixed populations have the highest asthma prevalence and severe asthma exacerbations rates. This could be explained not only by environmental factors but also by genetic variants that exert ethnic-specific effects. However, no admixture mapping has been performed for severe asthma exacerbations.

OBJECTIVE

We sought to identify genetic variants associated with severe asthma exacerbations in Hispanic/Latino subgroups by means of admixture mapping analyses and fine mapping, and to assess their transferability to other populations and potential functional roles.

METHODS

We performed an admixture mapping in 1124 Puerto Rican and 625 Mexican American children with asthma. Fine-mapping of the significant peaks was performed via allelic testing of common and rare variants. We performed replication across Hispanic/Latino subgroups, and the transferability to non-Hispanic/Latino populations was assessed in 1001 African Americans, 1250 Singaporeans and 941 Europeans with asthma. The effects of the variants on gene expression and DNA methylation from whole blood were also evaluated in participants with asthma and in silico with data obtained through public databases.

RESULTS

Genomewide significant associations of Indigenous American ancestry with severe asthma exacerbations were found at 5q32 in Mexican Americans as well as at 13q13-q13.2 and 3p13 in Puerto Ricans. The single nucleotide polymorphism (SNP) rs1144986 (C5orf46) showed consistent effects for severe asthma exacerbations across Hispanic/Latino subgroups, but it was not validated in non-Hispanics/Latinos. This SNP was associated with DPYSL3 DNA methylation and SCGB3A2 gene expression levels.

CONCLUSIONS

Admixture mapping study of asthma exacerbations revealed a novel locus that exhibited Hispanic/Latino-specific effects and regulated DPYSL3 and SCGB3A2.

Multi-ancestry genome-wide association study of asthma exacerbations

BACKGROUND

Asthma exacerbations are a serious public health concern due to high healthcare resource utilization, work/school productivity loss, impact on quality of life, and risk of mortality. The genetic basis of asthma exacerbations has been studied in several populations, but no prior study has performed a multi-ancestry meta-analysis of genome-wide association studies (meta-GWAS) for this trait. We aimed to identify common genetic loci associated with asthma exacerbations across diverse populations and to assess their functional role in regulating DNA methylation and gene expression.

METHODS

A meta-GWAS of asthma exacerbations in 4989 Europeans, 2181 Hispanics/Latinos, 1250 Singaporean Chinese, and 972 African Americans analyzed 9.6 million genetic variants. Suggestively associated variants (p ≤ 5 × 10^-5 ) were assessed for replication in 36,477 European and 1078 non-European asthma patients. Functional effects on DNA methylation were assessed in 595 Hispanic/Latino and African American asthma patients and in publicly available databases. The effect on gene expression was evaluated in silico.

RESULTS

One hundred and twenty-six independent variants were suggestively associated with asthma exacerbations in the discovery phase. Two variants independently replicated: rs12091010 located at vascular cell adhesion molecule-1/exostosin like glycosyltransferase-2 (VCAM1/EXTL2) (discovery: odds ratio (OR_{T allele} ) = 0.82, p = 9.05 × 10^-6 and replication: OR_{T allele}  = 0.89, p = 5.35 × 10^-3 ) and rs943126 from pantothenate kinase 1 (PANK1) (discovery: OR_{C allele}  = 0.85, p = 3.10 × 10^-5 and replication: OR_{C allele}  = 0.89, p = 1.30 × 10^-2 ). Both variants regulate gene expression of genes where they locate and DNA methylation levels of nearby genes in whole blood.

CONCLUSIONS

This multi-ancestry study revealed novel suggestive regulatory loci for asthma exacerbations located in genomic regions participating in inflammation and host defense.

Recurrent wheezing during the first 3 years of life in a birth cohort of moderate-to-late preterm infants

BACKGROUND

Data addressing short- and long-term respiratory morbidity in moderate-late preterm infants are limited. We aim to determine the incidence of recurrent wheezing and associated risk and protective factors in these infants during the first 3 years of life.

METHODS

Prospective, multicenter birth cohort study of infants born at 32⁺⁰ to 35⁺⁰  weeks' gestation and followed for 3 years to assess the incidence of physician-diagnosed recurrent wheezing. Allergen sensitization and pulmonary function were also studied. We used multivariate mixed-effects models to identify risk factors associated with recurrent wheezing.

RESULTS

A total of 977 preterm infants were enrolled. Rates of recurrent wheezing during year (Y)1 and Y2 were similar (19%) but decreased to 13.3% in Y3. Related hospitalizations significantly declined from 6.3% in Y1 to 0.75% in Y3. Independent risk factors for recurrent wheezing during Y2 and Y3 included the following: day care attendance, acetaminophen use during pregnancy, and need for mechanical ventilation. Atopic dermatitis on Y2 and male sex on Y3 were also independently associated with recurrent wheezing. Palivizumab prophylaxis for RSV during the first year of life decreased the risk or recurrent wheezing on Y3. While there were no differences in rates of allergen sensitization, pulmonary function tests (FEV_0.5 ) were significantly lower in children who developed recurrent wheezing.

CONCLUSIONS

In moderate-to-late premature infants, respiratory symptoms were associated with lung morbidity persisted during the first 3 years of life and were associated with abnormal pulmonary function tests. Only anti-RSV prophylaxis exerted a protective effect in the development of recurrent wheezing.

Isolated pulmonary interstitial glycogenosis associated with alveolar growth abnormalities: A long-term follow-up study

INTRODUCTION

Pulmonary interstitial glycogenosis (PIG) is a rare infant interstitial lung disease characterized by an increase in the number of interstitial mesenchymal cells, presenting as enhanced cytoplasmic glycogen, and is considered to represent the expression of an underlying lung development disorder.

METHODS

This study describes the clinical, radiological, and functional characteristics and long-term outcomes (median 12 years) of nine infants diagnosed with isolated PIG associated with alveolar simplification in the absence of other diseases.

RESULTS

All patients presented with tachypnea. Additionally, seven patients had breathing difficulties and hypoxemia. Abnormalities in chest-computerized tomography (CT) with a pattern of ground-glass opacity, septal thickening, and air trapping were observed in all individuals, with images suggesting abnormal alveolar growth (parenchymal bands and architectural distortion). All lung biopsies showed alveolar simplification associated with an increased number of interstitial cells, which appeared as accumulated cytoplasmic glycogen. In the follow-up, all patients were asymptomatic. The respiratory function test was normal in only two patients. Five children showed an obstructive pattern, and two children showed a restrictive pattern. Chest-CT, performed after an average of 6.5 years since the initial investigation, revealed a partial improvement of the ground-glass opacity pattern; however, relevant alterations persisted.

CONCLUSION

Although the patients with PIG in the absence of other associated pathologies had a good clinical outcome, significant radiographic alterations and sequelae in lung function were still observed after a median follow-up of 12 years, suggesting that PIG is a marker of some other persistent abnormalities in lung growth, which have effects beyond the symptomatic period.

Small Airway Dysfunction in Children With Controlled Asthma

INTRODUCTION

Asthma is characterized by chronic inflammation of the central and distal airways. The aim of this study was to assess the small airway (SA) of children with moderate-severe asthma with normal FEV1.

METHODS

This was an open-label, prospective, observational, cross-sectional study with consecutive inclusion of patients with moderate-severe asthma, receiving standard clinical treatment, with normal baseline FEV₁. We determined multiflow FEno (CAno), oscillatory resistance and reactance (R5-R20, X5), forced spirometry (FEV1, FEF_25-75), total body plethysmography (RV/TLC) and bronchodilation test. SA involvement was defined as: CAno>4.5 ppb, R5-R20>0.147kPa/L/s, X5<-0.18kPa/L, FEF_25-75<-1.65 z-score, RV/TLC>33%. Poor asthma control was defined as ≤ 19 points on the ACT questionnaire or ≤ 20 on the c-ACT.

RESULTS

In a cohort of 100 cases, 76 had moderate asthma and 24 had severe asthma; 71 children were classified as poorly controlled and 29 were well-controlled. In total, 77.78% of the group with all the correct determinations (n=72) showed ≥ 1 altered SA parameter and 48.61% ≥ 2 parameters. There were no differences between well-controlled or poorly controlled cases.

CONCLUSIONS

Children with moderate-severe asthma, with normal FEV₁, show a phenotype of dysfunctional SA. In our series, the evaluation of SA using the techniques described above did not provide information on disease control.

Quality of life in home-ventilated children and their families

HMV (home mechanical ventilation) in children has increased over the last years. The aim of the study was to assess perceived quality of life (QOL) of these children and their families as well as the problems they face in their daily life.We performed a multicentric cross-sectional study using a semi-structured interview about the impact of HMV on families and an evaluation questionnaire about perceived QOL by the patient and their families (pediatric quality of life questionnaire (PedsQL4.0)). We studied 41 subjects (mean age 8.2 years). Global scores in PedsQL questionnaire for subjects (median 61.4), and their parents (median 52.2) were below those of healthy children. 24.4% received medical follow-up at home and 71.8% attended school. Mothers were the main caregivers (75.6%), 48.8% of which were fully dedicated to the care of their child. 71.1% consider economic and healthcare resources insufficient. All families were satisfied with the care they provide to their children, even though it was considered emotionally overwhelming (65.9%). Marital conflict and neglect of siblings appeared in 42.1 and 36% of families, respectively.

CONCLUSIONS

Perceived QOL by children with HMV and their families is lower than that of healthy children. Parents are happy to care for their children at home, even though it negatively affects family life. What is Known: • The use of home mechanical ventilation (HMV) in children has increased over the last years. • Normal family functioning is usually disrupted by HMV. What is New: • The aim of HMV is to provide a lifestyle similar to that of healthy children, but perceived quality of life by these patients and their parents is low. • Most of the families caring for children on HMV agree that support and resources provided by national health institutions is insufficient.

Risk factors for bronchiolitis, recurrent wheezing, and related hospitalization in preterm infants during the first year of life

BACKGROUND

Airway diseases are highly prevalent in infants and cause significant morbidity. We aimed to determine the incidence and risk factors for respiratory morbidity in a Spanish cohort of moderate-to-late preterm (MLP) infants prospectively followed during their first year of life.

METHODS

SAREPREM is a multicenter, prospective, longitudinal study. Preterm infants born at 32-35 weeks of gestation with no comorbidities were enrolled within 2 weeks of life and followed at 2-4 weeks, 6, and 12 months of age. Multivariate mixed-models were performed to identify independent risk factors associated with (i) development of bronchiolitis, (ii) recurrent wheezing, or (iii) related hospital admissions.

RESULTS

Overall, 977 preterm infants were included, and 766 (78.4%) completed follow-up. Of those, 365 (47.7%) developed bronchiolitis during the first year, 144 (18.8%) recurrent wheezing, and 48 (6.3%) were hospitalized. While low birthweight, day care attendance (DCA) and school-age siblings were significantly and independently associated with both the development of bronchiolitis and recurrent wheezing, lower maternal age increased the risk for bronchiolitis and respiratory-related hospitalizations. Lastly, mechanical ventilation was associated with a higher risk of bronchiolitis and history of asthma in any parent increased the likelihood of developing recurrent wheezing.

CONCLUSIONS

In this study, several non-modifiable parameters (family history of asthma, low birthweight, need for mechanical ventilation) and modifiable parameters (young maternal age, DCA, or exposure to school-age siblings) were identified as significant risk factors for the development of bronchiolitis and recurrent wheezing during the first year of life in MLP infants.

Alveolar nitric oxide and its role in pediatric asthma control assessment

Background

Nitric oxide can be measured at multiple flow rates to determine proximal (maximum airway nitric oxide flux; Jaw_NO) and distal inflammation (alveolar nitric oxide concentration; CA_NO). The main aim was to study the association among symptoms, lung function, proximal (maximum airway nitric oxide flux) and distal (alveolar nitric oxide concentration) airway inflammation in asthmatic children treated and not treated with inhaled glucocorticoids.

Methods

A cross-sectional study with prospective data collection was carried out in a consecutive sample of girls and boys aged between 6 and 16 years with a medical diagnosis of asthma. Maximum airway nitric oxide flux and alveolar nitric oxide concentration were calculated according to the two-compartment model. In asthmatic patients, the asthma control questionnaire (CAN) was completed and forced spirometry was performed. In controls, differences between the sexes in alveolar nitric oxide concentration and maximum airway nitric oxide flux and their correlation with height were studied. The correlation among the fraction of exhaled NO at 50 ml/s (FE_NO50), CA_NO, Jaw_NO, forced expiratory volume in 1 second (FEV₁) and the CAN questionnaire was measured and the degree of agreement regarding asthma control assessment was studied using Cohen’s kappa.

Results

We studied 162 children; 49 healthy (group 1), 23 asthmatic participants without treatment (group 2) and 80 asthmatic patients treated with inhaled corticosteroids (group 3). CA_NO (ppb) was 2.2 (0.1-4.5), 3 (0.2-9.2) and 2.45 (0.1-24), respectively. Jaw_NO (pl/s) was 516 (98.3-1470), 2356.67 (120–6110) and 1426 (156–11805), respectively. There was a strong association (r = 0.97) between FE_NO50 and Jaw_NO and the degree of agreement was very good in group 2 and was good in group 3. There was no agreement or only slight agreement between the measures used to monitor asthma control (FEV₁, CAN questionnaire, CA_NO and Jaw_NO).

Conclusions

The results for CA_NO and Jaw_NO in controls were similar to those found in other reports. There was no agreement or only slight agreement among the three measure instruments analyzed to assess asthma control. In our sample, no additional information was provided by CA_NO and Jaw_NO.

Young infants with recurrent wheezing and positive asthma predictive index have higher levels of exhaled nitric oxide

OBJECTIVE

The aim of this post hoc analysis was to establish the relationship between FE(NO) levels and the asthma predictive index (API) among infants with recurrent wheezing.

METHODS

Infants with recurrent wheezing (three or more episodes) were recruited consecutively and online FE(NO) tests at tidal breathing with multiple breaths were performed.

RESULTS

Twenty-seven (84%) out of 32 infants (median age of 12 months) who met the inclusion criteria for this post hoc analysis, successfully performed the FE(NO) determinations. Eighteen (66%) infants were classified with positive stringent API. FE(NO) levels were significantly higher among patients with positive API than those with negative (median [IQR] of 12.3 [14.8] ppb vs. 4.1 [7.9] ppb, respectively, p = .016). Furthermore, FE(NO) and positive API had a significant correlation (Spearman's rho, ρ = 0.4741, p = .0125). After logistic regression analysis including FE(NO) levels, gender, age, and use of controller therapy, FE(NO) was the only variable that was marginally related to API (OR = 1.12, 95% CI: 0.99-1.27, p = .07).

CONCLUSION

Infants with recurrent wheezing who had a positive stringent API already had higher FE(NO) levels than those with a negative API. This finding needs to be corroborated in a larger prospective study.

[Endobronchial chondromesenchymal hamartoma]

Primary lung tumours are uncommon in childhood. Among these tumours, endobronchial masses are even less common and, among benign tumours, inflammatory pseudotumours and hamartomas have the highest incidence in children. We present the case of a 2.5-year-old girl with a left endobronchial chondromesenchymal hamartoma with obstruction of 90% of the bronchial lumen. Complete resection of the endobronchial mass was performed by rigid bronchoscopy and application of topical mitomycin C. After tumour resection and a 12-month follow-up, the patient has shown a favourable outcome with immediate disappearance of respiratory symptoms. Successive fibreoptic bronchoscopies have shown no residual tumour.

Obstructive Sleep Apnea-Hypopnea Syndrome in Children Is Not Associated With Obesity

OBJECTIVE

The prevalence of obstructive sleep apnea-hypopnea syndrome (OSAHS) in the general pediatric population ranges from 1% to 3%. However, its prevalence in an unselected population of obese children is unknown. We studied the association between obesity and OSAHS in children diagnosed with the syndrome in a cohort of boys and girls (age range, 2-14 years) referred to the pediatric respiratory medicine outpatient clinic at our hospital for suspected apnea, snoring, or both over the past 5 years.

PATIENTS AND METHODS

The medical history of each patient was recorded and all patients underwent a physical examination, chest and nasal cavities radiography, and 8-channel respiratory polygraphy during sleep. The following variables were evaluated: sex, reason for consultation, source of referral, findings during upper airway examination, age, weight z-score (reflecting how much a finding differs from the mean and in what direction in a normally distributed sample), height z-score, body mass index (BMI) z-score, number of apneas, number of hypopneas, apnea index, hypopnea index, apnea-hypopnea index (AHI), oxygen saturation (mean and minimum) measured by pulse oximetry, number of snores, and snore index.

RESULTS

Of the 400 patients studied, 242 (60.5%) were male and 158 (39.5%) female. The mean age was 4.95 years. OSAHS (AHI> or =3) was diagnosed in 298 cases (74.5%) and these patients were then studied to determine the relation between OSAHS and obesity. The anthropometric distribution (expressed as mean [SD]) was as follows: weight z-score, 0.37 (1.31); height z-score, 0.23 (1.19); BMI, 17.063 kg/m(2) (2.51); and BMI z-score, 0.39 (1.36). The respiratory polygraph during sleep recorded an AHI of 6.56 (7.56).

CONCLUSIONS

No differences were observed between the height z-score, weight z-score, BMI z-score, age, and AHI. No association between obesity and OSAHS was found in this series. However, studies of larger, unselected populations are needed to determine if obesity is a risk factor for OSAHS in children.

Evolución de dos pacientes con síndrome de Hurler en tratamiento con enzima recombinante humana α-L-iduronidasa

We performed a prospective study of two patients with Hurler's syndrome (aged 4.8 years and 17 months at the beginning of the intervention) under enzyme replacement therapy with human recombinant alpha-L-iduronidase for 452 and 28 weeks respectively. The aim of this study was to analyze the safety and efficacy of the intervention during the treatment periods. Several diagnostic imaging tests, clinical examinations, and serial laboratory determinations were performed to demonstrate the effectiveness of the therapy in both patients. In patient 1 (a boy aged 4.8 years, homozygote W402X), the treatment was always intended to be palliative because of the advanced stage of the disease. In patient 2 (a 17-month-old girl, heterozygote W402X) the treatment was initiated early with subsequent clinical stabilization without acquisition of regressive factors. Bone marrow transplantation from an unrelated donor was successful. Currently, because of the lack of histocompatible bone marrow donors, transplantation of hematopoietic stem cells from umbilical cord blood or peripheral blood are being performed with satisfactory results. In the future, gene therapy may be able to prevent the diseases associated with Hurler's syndrome and halt the neurocognitive deterioration characteristic of these patients.

Características clínicas de los niños hospitalizados por infección por virus Influenza

BACKGROUND

The clinical manifestations of influenza virus are fairly nonspecific and are similar to those of other viral infections, respiratory processes due to other causes and even septic disease in neonates. Few studies have been performed of the clinical characteristics of influenza virus infection in hospitalized children.

OBJECTIVE

To evaluate the clinical characteristics of children hospitalized for influenza virus infection in four consecutive epidemic waves (2000-2004).

MATERIAL AND METHODS

We retrospectively reviewed the medical records of children hospitalized for influenza A and B virus infection confirmed by cell culture and polymerase chain reaction. Age, sex, symptoms on admission, complementary investigations, diagnosis and outcome were evaluated.

RESULTS

Eighty-four children were hospitalized, of which 74 had influenza virus type AH3, five had influenza virus type AH1 and five had influenza B virus. A total of 42.8 % were aged less than 6 months. The main symptoms were fever (75 patients), cough (56 patients) and ENT involvement (53 patients). The most frequent causes of admission were febrile syndrome (75 patients), bronchiolitis (19 patients), pneumonia (13 patients) and bronchitis (8 patients). In 21 patients viral or bacterial coinfection was found, the most frequent of which was respiratory syncytial virus (10 patients). Few differences were found among age groups except for pneumonia and prolonged fever (more frequent in children older than 6 months) and lymphocytosis (in children younger than 6 months). The greatest number of complementary investigations in younger children was performed for acute febrile syndrome in neonates aged less than 6 months. Risk factors for hospitalization were found in only three children, all of whom were older than 6 months. Outcome was favorable in all children.

CONCLUSIONS

Influenza virus infection in hospitalized children is most frequent in previously healthy neonates with fever and nonspecific signs and symptoms that are similar to those of other infectious processes. Specific microbiological diagnostic techniques are required for an early diagnosis. Healthy infants aged less than 24 months are most at risk for hospitalization for influenza virus infection.

[Psychogenic cough: Another etiology for persistent cough]

The most common causes of persistent cough are upper respiratory tract disease (postnasal drip syndrome, infections) and asthma. In the last year, six patients (four boys and two girls), aged 7-12 years old, with a diagnosis of hard-to-manage asthma and/or persistent cough were referred to our department. All the patients had undergone treatment with multiple drugs for long periods without favorable clinical response. The findings of physical examination, radiology, basal pulmonary function and post-bronchodilation and fibrobronchoscopy were normal. Organic disease was ruled out and a psychiatric evaluation was performed. Intelligence quotient was in the lower normal range and generalized anxiety order was identified, thus establishing a diagnosis of psychogenic cough. Treatment consisted of relaxation techniques and psychopedagogic support with favorable outcome. To avoid diagnostic errors and inappropriate treatment, psychogenic cough should be included in the differential diagnosis of persistent cough and hard-to-manage asthma.