Allergic airway diseases in childhood - marching from epidemiology to novel concepts of prevention

Update meta-analysis on the efficacy and safety issues of fexofenadine

Background

Fexofenadine emerged as one of the most representative second generation histamine H1 antagonist drugs since the 1990s, with an outstanding efficacy and appreciable safety for the treatment of allergic patients. While allergic rhino-conjunctivitis represents the most frequent atopic disease globally, an update of fexofenadine efficacy and safety on this entity was proposed as a surrogate of allergic condition.

Methods

Double blind, placebo controlled, randomized clinical trials investigating the efficacy and safety of fexofenadine for the treatment of Allergic Rhinitis were searched in 5 major global databases. Eligibility criteria and characteristics, risk of bias, and validity assessment, data extraction and heterogeneity evaluation are described. Primary outcome selected corresponded to 12-reflective and instantaneous total symptom scores (TSS), besides morning instantaneous TSS and the frequency of reported adverse events (AEs); analysis was planned on the intention-to-treat population.Standardized mean differences of scoring systems were analyzed, and Cochran's Q statistic test and the I2 test were assessed for heterogeneity.

Results

From the initial 83 identified records, 12 eligible studies were selected. In the evaluated patients, individuals receiving fexofenadine (1910) showed a significant reduction of TSS compared with those who received placebo (1777), change from baseline: standardized mean difference (SMD) -0.33; 95% CI-0.47 to -0.18, p < 0.0001. Morning instantaneous TSS also demonstrated lower symptoms (change from baseline: SMS -1.42; 95% CI -2.22 to -0.62, p = 0.0005). Heterogeneity was found across selected studies.Frequency of AEs was similar compared to placebo (OR = 1.04; 0.88-1.21), with no detection of heterogeneity across these 12 studies.

Conclusions

According to this new evidence, fexofenadine maintains its beneficial profile on signs and symptoms of patients with allergic conditions, as well as its attributes as one of the major candidates for an ideal antihistamine medication (including special conditions such as pregnancy and pre-school age), providing support to its over-the-counter condition in several countries.

COVID-19 scenario and recommendations on the continuity of immunobiological therapy in patients with atopic asthma in Brazil and Latin America

INTRODUCTION

With the abrupt establishment of the COVID-19 pandemic, treatment for immunological diseases may be influenced by the SARS-CoV-2 infection, including asthma and other allergies. Immunobiologics play a pivotal role in the management of severe symptoms of allergy and an opinion regarding the continuity of this treatment during the COVID-19 pandemic must be issued.

AREAS COVERED

In Brazil and other countries, patients with severe asthma were included in the priority groups for COVID-19 vaccination, even those who are undergoing immunobiological therapy. Data are insufficient to support the influence of this therapy on severe COVID-19 as targeting molecules may play a role in the physiopathology of the infection. Therapeutic strategies for asthma and guidelines/statements of the main societies of Allergy in Latin America on the continuity of treatment with immunobiologics during the COVID-19 pandemic were obtained from the institutional websites, PubMed, Scielo, Google Scholar, and CINAHL electronic platforms by searching for papers published up to September 2021.

EXPERT OPINION

Although the association between asthma and COVID-19 has been under investigation, immunobiological treatment should follow the consensus-based statements recommending the maintenance of the therapy unless the patient is infected by the SARS-CoV-2. However, it must be closely followed by the medical assistant.

Early-life exposure to air pollution and childhood allergic diseases: an update on the link and its implications

INTRODUCTION

Although mounting evidence has linked environmental factors with childhood allergies, some specific key issues still remain unclear: what is the main environmental factor? what is the critical timing window? And whether these contribute to the development of disease?

AREAS COVERED

This selective review summarizes recent epidemiological studies on the association between early-life exposure to indoor/outdoor air pollution and childhood allergic diseases. A literature search was conducted in the PubMed and Web of Science for peer-reviewed articles published until April 2020. Exposure to the traffic-related air pollutant, NO₂, exposure during pregnancy and early postnatal periods is found to be associated with childhood allergies, and exposure during different trimesters causes different allergic diseases. However, exposure to classical air pollutants (PM₁₀ and SO₂) also contributes to childhood allergy in developing countries. In addition, early-life exposure to indoor renovation and mold/dampness significantly increases the risk of allergy in children. A synergistic effect between indoor and outdoor air pollution is found in the development of allergic diseases.

EXPERT OPINION

Early-life exposure to outdoor air pollution and indoor environmental factors plays an important role in the development of childhood allergic diseases, and the synergy between indoor and outdoor exposures increases allergy risk. The available findings support the hypothesis of the 'fetal origins of childhood allergy,' with new implications for the effective control and early prevention of childhood allergies.

The effects of PM2.5 on asthmatic and allergic diseases or symptoms in preschool children of six Chinese cities, based on China, Children, Homes and Health (CCHH) project

The urbanization and industrialization in China is accompanied by bad air quality, and the prevalence of asthma in Chinese children has been increasing in recent years. To investigate the associations between ambient PM_2.5 levels and asthmatic and allergic diseases or symptoms in preschool children in China, we assigned PM_2.5 exposure data from the Global Burden of Disease (GBD) project to 205 kindergartens at a spatial resolution of 0.1° × 0.1° in six cities in China (Shanghai, Nanjing, Chongqing, Changsha, Urumqi, and Taiyuan). A hierarchical multiple logistical regression model was applied to analyze the associations between kindergarten-level PM_2.5 exposure and individual-level outcomes of asthmatic and allergic symptoms. The individual-level variables, including gender, age, family history of asthma and allergic diseases, breastfeeding, parental smoking, indoor dampness, interior decoration pollution, household annual income, and city-level variable-annual temperature were adjusted. A total of 30,759 children (average age 4.6 years, 51.7% boys) were enrolled in this study. Apart from family history, indoor dampness, and decoration as predominant risk factors, we found that an increase of 10 μg/m³ of the annual PM_2.5 was positively associated with the prevalence of allergic rhinitis by an odds ratio (OR) of 1.20 (95% confidence interval [CI] 1.11, 1.29) and diagnosed asthma by OR of 1.10 (95% CI 1.03, 1.18). Those who lived in non-urban (vs. urban) areas were exposed to more severe indoor air pollution arising from biomass combustion and had significantly higher ORs between PM_2.5 and allergic rhinitis and current rhinitis. Our study suggested that long-term exposure to PM_2.5 might increase the risks of asthmatic and allergic diseases or symptoms in preschool children in China. Compared to those living in urban areas, children living in suburban or rural areas had a higher risk of PM_2.5 exposure.

Prevention of allergies in childhood - where are we now?

Allergic diseases represent an increasing health problem for children worldwide. Along with allergic airway diseases, food allergy comes to the fore and herewith closely intertwined the hypothesis that an early allergic sensitization might occur via skin barrier defect(s). The importance of the skin barrier has been documented by several studies meanwhile. Not only genetic studies screen the associations between Filaggrin loss-of-function mutations, atopic dermatitis, allergic sensitization, food allergy and even airway diseases, but also epidemiological studies cast new light on the hypothesis of the atopic march. As another focus in context of the development of an allergic phenotype, the specific microbial exposure with all its diversities has been crystallized as it shapes the immune system in (early) infancy. Studies explored both, the role of human intestinal microbiota as well as the external microbial diversity. Unfortunately suitable markers for atopic predictors are still rare. New studies point out that specific IgE antibodies (e.g., IgE to Phl p 1) in children without allergic symptoms so far, might function as a pre-clinical biomarker, which may help to identify candidates for primary (allergen non-specific) or secondary (allergen-specific) prevention in terms of specific immunoprophylaxis. These manifold research activities document a complex increase in knowledge. Nevertheless new assumptions need to be substantively confirmed in order to finally generate the urgently needed preventive strategies for allergic diseases in childhood.

Non-allergic rhinitis in children: Epidemiological aspects, pathological features, diagnostic methodology and clinical management

Chronic rhinitis is a very common disease, as the prevalence in the general population resulted to be 40%. Allergic rhinitis has been considered to be the most frequent form of chronic rhinitis, as non-allergic rhinitis has been estimated to account for 25%. However, several evidences suggested that non-allergic rhinitis have been underrated, especially in children. In pediatrics, the diagnostic definition of non-allergic rhinitis has been often limited to the exclusion of an allergic sensitization. Actually, local allergic rhinitis has been often misdiagnosed as well as mixed rhinitis has not been recognized in most cases. Nasal cytology is a diagnostic procedure being suitable for routine clinical practice with children and could be a very useful tool to characterize and diagnose non-allergic rhinitis, providing important clues for epidemiological analysis and clinical management.

Air pollution, epigenetics, and asthma

Exposure to traffic-related air pollution (TRAP) has been implicated in asthma development, persistence, and exacerbation. This exposure is highly significant as large segments of the global population resides in zones that are most impacted by TRAP and schools are often located in high TRAP exposure areas. Recent findings shed new light on the epigenetic mechanisms by which exposure to traffic pollution may contribute to the development and persistence of asthma. In order to delineate TRAP induced effects on the epigenome, utilization of newly available innovative methods to assess and quantify traffic pollution will be needed to accurately quantify exposure. This review will summarize the most recent findings in each of these areas. Although there is considerable evidence that TRAP plays a role in asthma, heterogeneity in both the definitions of TRAP exposure and asthma outcomes has led to confusion in the field. Novel information regarding molecular characterization of asthma phenotypes, TRAP exposure assessment methods, and epigenetics are revolutionizing the field. Application of these new findings will accelerate the field and the development of new strategies for interventions to combat TRAP-induced asthma.

Cysteinyl leukotriene receptor antagonist epigenetically modulates cytokine expression and maturation of human myeloid dendritic cells

BACKGROUND

Cysteinyl leukotriene receptor antagonists are important controllers in treating asthma. Human myeloid DCs (mDCs) play critical roles in the pathogenesis of asthma. However, the effects of cysteinyl leukotriene receptor antagonist on human mDCs are unknown.

METHODS

To investigate the effects of cysteinyl leukotriene receptor antagonist on the function of human mDCs, circulating mDCs were isolated from six health subjects. Human mDCs were pretreated with montelukast and were stimulated with toll-like receptor (TLR) ligands lipopolysaccharide (LPS) or polyinosinic-polycytidylic acid (poly I:C). Tumor necrosis factor (TNF)-α and interleukin (IL)-10 were measured by ELISA. Intracellular signaling was investigated by pathway inhibitors, western blot and chromatin immunoprecipitation. Costimulatory molecules expression was investigated by flow cytometry. T cell polarization function of mDCs was investigated by measuring interferon (IFN)-γ, IL-13, IL-10 and IL-17A production by T cells using mDC/T cell coculture assay.

RESULTS

Montelukast suppressed TLR-mediated TNF-α expression via the NFκB-p65 and mitogen-activated protein kinase (MAPK)-JNK pathway, and enhanced TLR-mediated IL-10 expression via the MAPK-p38 pathway and epigenetic regulation by histone H3 acetylation. Montelukast suppressed LPS-induced CD80, CD86, CD40 and HLA-DR expression. Montelukast-treated mDCs suppressed IFN-γ and IL-13 production by T cells.

CONCLUSION

Cysteinyl leukotriene receptor antagonist alters the function of human mDCs by epigenetically modulating cytokine expression, suppressing costimulatory molecules expression and inhibiting the ability to initiate Th1/Th2 responses. The effects of cysteinyl leukotriene receptor antagonist on human mDCs can be an important mechanism in treating asthma.

Air pollution and allergic diseases

PURPOSE OF REVIEW

Exposure to traffic-related air pollutants (TRAPs) has been implicated in asthma development, persistence, and exacerbation. This exposure is highly significant because increasingly large segments of the population worldwide reside in zones that have high levels of TRAP, including children, as schools are often located in high traffic pollution exposure areas.

RECENT FINDINGS

Recent findings include epidemiologic and mechanistic studies that shed new light on the impact of traffic pollution on allergic diseases and the biology underlying this impact. In addition, new innovative methods to assess and quantify traffic pollution have been developed to assess exposure and identify vulnerable populations and individuals.

SUMMARY

This review will summarize the most recent findings in each of these areas. These findings will have a substantial impact on clinical practice and research by the development of novel methods to quantify exposure and identify at-risk individuals, as well as mechanistic studies that identify new targets for intervention for individuals most adversely affected by TRAP exposure.

Contributing factors to the development of childhood asthma: working toward risk minimization

Asthma is the most common chronic disease in childhood, and considerable research has been undertaken to find ways to prevent its development and reduce its prevalence. For such interventions to be successful, risk factors for asthma emergence should be identified and clearly defined. Data are robust for some of them, including atopy, viral infections and exposure to airborne irritants, whereas it is less conclusive for others, such as aeroallergen exposure and bacterial infections. Several interventions for asthma prevention, including avoidance and pharmacotherapy, have been attempted. However, most of them have furnished equivocal results. Various issues hinder the establishment of risk factors for asthma development and reduce the effectiveness of interventions, including the complexity of the disease and the fluidity of the developing systems in childhood. In this review, we revisit the evidence on pediatric asthma risk factors and prevention and discuss issues that perplex this field.

Spectrum of outpatient illness in a school-based cohort in Haiti, with a focus on diarrheal pathogens

Currently, there are only limited data available on rates of major diagnostic categories of illnesses among Haitian children. We have established a cohort of 1,245 students attending schools run by the Christianville Foundation in the Gressier/Leogane region of Haiti, for whom our group provides primary medical care. Among 1,357 clinic visits during the 2012–2013 academic year, the main disease categories (with rates per 1,000 child years of observation) included acute respiratory infection (ARI) (385.6 cases/1,000 child years of observation), gastrointestinal complaints (277.8 cases/1,000 child years), febrile illness (235.0 cases/1,000 child years), and skin infections (151.7 cases/1,000 child years). The most common diarrheal pathogen was enteroaggregative Escherichia coli (present in 17% of children with diarrhea); Vibrio cholerae O1 and norovirus were the next most common. Our data highlight the importance of better defining etiologies for ARI and febrile illnesses and continuing problems of diarrheal illness in this region, including mild cases of cholera, which would not have been diagnosed without laboratory screening.

Budget impact model of a 5-grass sublingual immunotherapy tablet for the treatment of grass pollen-induced allergic rhinitis

OBJECTIVE

Allergic rhinitis (AR) is a chronic disease with a substantial clinical and economic burden. This study estimated the potential budget impact (BI) associated with market entry of Sweet Vernal, Orchard, Perennial Rye, Timothy, and Kentucky Blue Grass Mixed Pollens Allergen Extract Tablet for Sublingual Use ('5-grass SLIT tablet') for patients aged 10-65 with grass pollen-induced AR.

METHODS

A budget impact model was constructed to estimate the potential BI from a US payer perspective. The model calculated pharmacy, medical, and total (pharmacy + medical) costs per-member-per-month (PMPM) with and without market entry of the 5-grass SLIT tablet, considering a 3-year time horizon. The target population was determined using an epidemiological approach and existing literature. The treatment market shares without 5-grass SLIT tablet entry were derived from an analysis of de-identified insurance claims data. Pharmacy costs and medical utilization rates and costs were obtained from the claims data analysis and existing literature. One-way sensitivities were conducted for key model inputs.

RESULTS

Using an illustrative example of a hypothetical health plan with one million members, the estimated target population of AR patients aged 10-65 was 26,320. On a PMPM basis, pharmacy costs increased by $0.36, $0.44, and $0.51, while total costs (after medical cost offsets) increased by $0.15, $0.18, and $0.22 in the first, second, and third years following entry of the 5-grass SLIT tablet, respectively. Results were most sensitive to changes in the compliance rate, treatment duration, and price. The BI will vary from the base case example when alternative, payer-specific inputs are used.

CONCLUSIONS

Using base case inputs, use of the 5-grass SLIT tablet to treat grass pollen-induced AR increased the pharmacy budget for a hypothetical third-party payer. Higher pharmacy costs were partially offset by lower medical budget due to reduced resource use compared with existing treatments.

Management of allergic rhinitis

In this paper, we review the current management of allergic rhinitis and new directions for future treatment. Currently, management includes pharmacotherapy, allergen avoidance and possibly immunotherapy. The simple washing of nasal cavities using isotonic saline provides a significant improvement and is useful, particularly in children. The most effective medication in persistent rhinitis used singly is topical corticosteroid, which decreases all symptoms, including ocular ones. Antihistamines reduce nasal itch, sneeze and rhinorrhea and can be used orally or topically. When intranasal antihistamine is used together with topical corticosteroid, the combination is more effective and acts more rapidly than either drug used alone. Alternative therapies, such as homeopathy, acupuncture and intranasal carbon dioxide, or devices such nasal air filters or intranasal cellulose, have produced some positive results in small trials but are not recommended by Allergic Rhinitis and its Impact on Asthma (ARIA). In the field of allergic immunotherapy, subcutaneous and sublingual routes are currently used, the former being perhaps more efficient and the latter safer. Sublingual tablets are now available. Their efficacy compared to standard routes needs to be evaluated. Efforts have been made to develop more effective and simpler immunotherapy by modifying allergens and developing alternative routes. Standard allergen avoidance procedures used alone do not provide positive results. A comprehensive, multi-trigger, multi-component approach is needed, including avoidance of pollutants such as cigarette smoke.

Component-resolved diagnosis in pediatric allergic rhinoconjunctivitis and asthma

PURPOSE OF REVIEW

The aim of this review is to update readers on the growing impact of a molecular approach (CRD) to the diagnosis and treatment of children with respiratory allergies

RECENT FINDINGS

A large panel of highly purified natural or recombinant species-specific and cross-reacting allergenic molecules is now available for clinical purposes. Species-specific molecules allow identifying specific sensitization toward a given allergenic source. Cross-reacting molecules allow interpreting polysensitization patterns that cannot be detailed using routine skin prick tests or specific IgE tests based on allergenic extracts. These molecular tools are transforming and improving the interpretation of clinical and laboratory tests used to define patients' IgE-sensitization profile.

SUMMARY

The accurate dissection of the IgE repertoire offers new possibilities in the diagnosis, prophylaxis and treatment of pediatric allergic rhinoconjunctivitis and asthma.

Breastfeeding and wheeze prevalence in pre-schoolers and pre-adolescents: the Genesis and Healthy Growth studies

BACKGROUND

To date, extensive research has been undertaken on a potential link of breastfeeding (BF) to wheezing illnesses. Nevertheless, an association remains to be established, partly due to age-dependent discrepancies and different definitions of exposures/outcomes across studies. We thus investigated the relation of diverse infantile feeding patterns with wheeze/asthma prevalence in two cohorts of children of different ages (preschool and preadolescent).

METHODS

Wheeze ever/in the last 12 months (current) and doctor-diagnosed asthma were retrospectively reported by parents of the participants of two cross-sectional studies: the Genesis study (1871 children aged 1-5) and the Healthy Growth study (1884 children aged 9-13). Information on feeding practices (exclusive breastfeeding vs. mixed vs. formula feeding) and their duration (2 vs. 4 vs. 6 months) was recorded. Perinatal and anthorpometric data were also collected.

RESULTS

In pre-schoolers, regimes that did not entail exclusive BF were positively correlated to current/ever wheeze, both before and after adjustment for confounders. No differences between the associations of regimes with 2, 4 or 6 months of exclusive BF with current/ever wheeze were shown. Furthermore, there was no consistent correlation of feeding practices with physician-diagnosed asthma. In pre-adolescents, no association of infantile feeding patterns with the wheeze/asthma outcomes was observed.

CONCLUSIONS

Exclusive BF is associated with reduced prevalence of current/ever wheeze in pre-schoolers; however, this appears to wane in older children. The association of a period of exclusive BF as low as 2 months with pre-school wheeze prevalence, appeared to be comparable with that of 6 months of exclusivity.

Antibiotic exposure in the first two years of life and development of asthma and other allergic diseases by 7.5 yr: a dose-dependent relationship

BACKGROUND

Antibiotic use in infancy disrupts gut microflora during a critical period for immune system development. It is hypothesized that this could predispose to the development of allergic diseases. We investigated the associations of antibiotic use in the first 2 yr of life with the development of asthma, eczema or hay fever by age 7.5 yr in a longitudinal birth cohort.

METHODS

Subjects were 4952 children from the Avon Longitudinal Study of Parents and Children (ALSPAC). Child antibiotic use and asthma, eczema and hay fever symptoms were maternally reported. Atopy was assessed by skin prick tests at age 7.5 yr. The total number of antibiotic courses was considered as the main exposure. Data were analysed using multivariate logistic regression.

RESULTS

Children reported to have taken antibiotics during infancy (0-2 yr) were more likely to have asthma at 7.5 yr (OR 1.75, 95% CI 1.40-2.17), and the odds (OR, [95% CI]) increased with greater numbers of courses: once 1.11 [0.84-1.48]; twice 1.50 [1.14-1.98]; three times 1.79 [1.34-2.40]; four times or more 2.82 [2.19-3.63]. Increased antibiotic use was also associated with higher odds of eczema and hay fever but not atopy. The effect appeared to be associated with cumulative rather than a critical period of exposure during the first 2 yr.

CONCLUSIONS

A robust and dose-dependent association was found between antibiotic use in the first 2 yr of life and asthma at age 7.5 yr but did not appear to be mediated through an association with atopy.

Allergology in Europe, the blueprint

The number of patients with allergic diseases in Europe, and thus relevant demand for health care, is continuously increasing. In this EAACI-UEMS position paper, a rationale is given for the medical specialty of allergology. General practitioners and general paediatricians usually cannot elucidate and address all causative factors. Throughout Europe, therefore, the expertise of allergologists (allergists) is required. In collaboration with other medical professionals, they take care of allergic patients, in private practices or in specialized public centres. A well-structured collaboration between allergists and allergy centres offers the possibility of rapid signalling of new trends developing in the population of allergic patients (e.g., in food and drug allergy). Allergy centres also can perform clinical (and basic) research, teach medical students, future allergists and provide postgraduate training. To prevent that the quality of care in one or several countries within Europe lags behind developments in other countries, the UEMS Section and Board on Allergology together with the European Academy of Allergy and Clinical Immunology advocates the status of a full specialty of allergology in each European country, with a further intention to align their activities (blueprint, curriculum and centre visitation) with the UEMS Section of Paediatrics.

The pathophysiology of the hygiene hypothesis

There has been a considerable increase in the diagnosis of allergic diseases over the last decades. Prevalence of allergies in high-income countries and urban areas appears higher than in rural environments. While environmental factors like pollution or nutrition can be important, it is more likely that in the end they have a small association with allergies. Childhood infections and exposure to certain microbial antigens on the other hand seem to present a strong negative correlation with allergies, and therefore the increase of the allergic burden in the Western world has been frequently related to a decline of childhood infections giving birth to the "Hygiene Hypothesis". We address the issue with emphasis on the associated pathophysiology tightrope walking between the skepticism of the critics, which cast doubt on it, and the pilgrims' belief of having discovered allergy's Holy Grail.