Local allergic rhinitis: A critical reappraisal from a paediatric perspective

The Very Low IgE Producer: Allergology, Genetics, Immunodeficiencies, and Oncology

Opposite to other immunoglobulin (Ig) classes and subclasses, there is no consensus on the definition of normal levels of serum total IgE. However, longitudinal studies on birth cohorts produced growth charts of total IgE levels in helminth-free and never atopic children and defining the normal ranges of total serum IgE concentration at the individual, rather than population, level. Accordingly, very 'low IgE producers' (i.e., children whose tIgE level belong to the lowest percentiles) became atopic while keeping their total IgE levels in a range considered 'normal' if compared to the general age-matched population but 'abnormally high' if projected on the tIgE growth chart against the trajectory of that child's own percentile levels. In 'low IgE producers', the IgE-specific activity, i.e., the ratio between allergen-specific and total IgE, is more important than the absolute specific IgE levels to confirm causality between allergen exposure and allergic symptoms. Patients with allergic rhinitis or peanut anaphylaxis but low or undetectable allergen-specific IgE levels must therefore be reconsidered considering their total IgE levels. Low IgE producers have been also associated with common variable immunodeficiency, lung diseases, and malignancies. A few epidemiological studies have shown a higher risk of malignancies in very low IgE producers, leading to a debated hypothesis proposing a novel, evolutionistic-relevant function for IgE antibodies for antitumor immune surveillance.

The Role of Allergen-Specific Immunotherapy in ENT Diseases: A Systematic Review

Previous studies have demonstrated that both subcutaneous (SCIT) and sublingual specific immunotherapy (SLIT) are effective in treating allergic rhinitis (AR). Further studies have evaluated the efficacy of allergen-specific immunotherapy (AIT) on different ear, nose, and throat (ENT) manifestations, in which allergy might have an etiopathogenetic role, such as local allergic rhinitis (LAR), rhinosinusitis (RS), otitis media (OM), and adenotonsillar (AT) disease. Nevertheless, the management of allergy in ENT diseases is still debated. To the best of our knowledge, this is the first systematic review assessing the efficacy of AIT in ENT diseases aside from AR. Literature data confirmed that AIT might be an effective therapeutic option in LAR, although its effect is restricted to studies with short-term follow-up. Furthermore, previous research demonstrated that AIT may improve symptoms and surgical outcomes of chronic rhinosinusitis when used as an adjunctive treatment. Few studies supported the hypothesis that AIT may exert positive therapeutic effects on recurrent upper airway infections as adenotonsillar disease. Finally, some clinical observations suggested that AIT may add some benefits in the management of otitis media with effusion (OME). The results of this systematic review allow us to conclude that the efficacy of AIT in ENT disorders has been only slightly investigated and additional studies are needed.

Allergic rhinitis as a key factor for the development of gastroesophageal reflux disease in children

BACKGROUND

Gastroesophageal reflux disease (GERD) may cause airway symptoms and some airway diseases exacerbate GERD symptoms. Asthma and allergic rhinitis (AR) have been identified as united airway disease because of their similar epidemiology and pathophysiology. Asthma has been considered a risk factor to develop GERD. However, the association between AR and GERD is not clear. We tried to investigate whether AR could increase the development of GERD.

METHODS

Children diagnosed as AR without a prior history of GERD were conducted from the National Health Insurance Research Database between 2000 and 2005. After propensity score matching, we enrolled 36,588 children with AR and 36,588 non-AR children as the controls. Cox regression models were adopted to calculate the hazard ratio (HR) of GERD.

RESULTS

AR children had a significantly increased risk of GERD than non-AR children (adjusted HR 1.91, 95% CI = 1.73-2.11, p < 0.001), especially in the age less than 6 years old (adjusted HR 2.68, 95% CI = 1.64-4.38, p < 0.001). The risk factor related to increased risk of GERD including age, gender, and chronic sinusitis.

CONCLUSION

AR is a risk factor associated with the development of GERD in children.

Integrated genetic and epigenetic analyses uncover MSI2 association with allergic inflammation

BACKGROUND

The relationship between allergic and eosinophilic inflammation, either systemic or local, in allergic diseases remains unclear.

OBJECTIVE

We performed combined genome-wide association study (GWAS) and epigenome-wide (EWAS) for atopy and tissue eosinophilia to identify both genetic and epigenetic signatures between systemic and local allergic inflammation, and to capture global patterns of gene regulation.

METHODS

We included 126 subjects for atopy analysis and 147 for tissue eosinophilia analysis, as well as 18 normal nasal tissue samples. We identified differentially methylated positions (DMPs) and genes associated with atopy and tissue eosinophilia. Furthermore, we performed mendelian randomization analysis and penalized regression along with replication in an independent cohort.

RESULTS

EWAS identified genes, including Musashi RNA binding protein 2 (MSI2), associated with atopy, which contained enriched DMPs that genetically affect atopy. A direct association was observed between MSI2 single-nucleotide polymorphisms and atopy, as was a causal effect of changes in MSI2 expression and methylation on atopy, which was replicated in a Costa Rican population. Regarding tissue eosinophilia, EWAS identified genes with enriched DMPs directly contributing to tissue eosinophilia at the gene level, including CAMK1D. The gene ontology terms of the identified genes for both phenotypes encompassed immune-related terms.

CONCLUSION

EWAS combined with GWAS identified novel candidate genes, especially the methylation of MSI2, contributing to systemic allergic inflammation. Certain genes displayed a greater association with either systemic or local allergic inflammation; however, it is expected that a harmonized effect of these genes influences immune responses.

Dilemmas associated with local allergic rhinitis

Local allergic rhinitis (LAR) in patients with no systemic markers of atopy is a very interesting phenomenon due to the lack of any definitive explanation for the mechanism of this IgE-dependent reaction. Some of the recent attempts to explain this phenomenon consider LAR to be closely associated with an allergic reaction, some suggest that this phenomenon is a spontaneous process in the nasal mucosa. Future attempts to elucidate the complexity of inflammatory reactions will undoubtedly establish a clear differential diagnostics algorithm for rhinitis.

The role of local allergy in the nasal inflammation

Local allergic inflammation (LAI) is recognized recently. 'entopy' was used to define LAI, which was positively correlated with allergen provocation testing, local sIgE up-regulation, inflammatory mediator secretion, and a lack of systemic allergy. The study of LAI is in its infancy and focuses mainly on the respiratory system. It is closely related to nasal inflammation and plays important roles in patients with nonallergic rhinitis (NAR), nonallergic chronic sinusitis with nasal polyps (CRSwNP), and nonallergic fungal rhinosinusitis (NAFRS). Based on studies using nasal allergen provocation testing, 40-57% of patients with NAR exhibited positive results and could be diagnosed as local allergic rhinitis. Total IgE and common airborne allergen-sIgE were up-regulated in eosinophilic CRSwNP patients compared to noneosinophilic CRSwNP patients and healthy controls, possibly due to local allergic inflammation. Some researchers also found that the level of local sIgE was increased in patients with NAFRS; they suggested that local allergic inflammation occurs in NAFRS. Studies of LAI will increase our understanding of nasal inflammation and help to establish novel treatments. However, the diagnosis of local allergic inflammation is complex due to the lack of convenient detection methods. The relationship between local allergic inflammation and systemic allergic inflammation is unclear, and an appropriate treatment for local allergic inflammation is required.

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.

Asthma and allergic rhinitis in childhood: what's new

Novel approaches are currently offered for the diagnostic workup and therapeutic management of allergic rhinitis and asthma. New predictive biomarkers of allergy and asthma are available. Primary and secondary prevention, earlier intervention, and modification of the natural history of allergic rhinitis and asthma are being intensively investigated. This review highlights advances in the understanding of the etiology, diagnosis, and management of atopic airway diseases in childhood, as well as prenatal and early-life risk factors and strategies for prevention.