Comparison of Timothy grass pollen extract- and single major allergen-induced gene expression and mediator release in airway epithelial cells: a meta-analysis

lncRNA profiling in NCI-H292 cells after stimulation with Dermatophagoides farinae extracts

Airway epithelium cells are the first line of defense against airborne allergens. When cultured, epithelial cells can be exposed to various allergens, providing an ideal model to investigate allergic disorders. This study sought to characterize the profile of long noncoding (lnc) RNAs, which can regulate gene expression and exert functions in diverse cellular processes, in airway epithelial cells exposed to house dust mite allergens. NCI-H292 cells were exposed to house dust mite extract for 24 h. RNA expression was profiled in exposed and unexposed cells. There were 270 lncRNAs that were differentially expressed (fold change ≥ 2, P < 0.05) in NCI-H292 cells after stimulation with Dermatophagoides farinae (house dust mite) extracts. Furthermore, 119 lncRNAs and 22 messenger RNAs were co-expressed. Gene Ontology analysis showed that these under-regulated and up-regulated lncRNAs were associated with biological process, cellular component, and molecular function. After bioinformatic analysis of significantly regulated signaling pathways, we found these lncRNAs may target 16 gene pathways, including glycolysis, axon guidance, ErbB signaling, and mitogen-activated protein kinases (MAPK) signaling. The identification of differentially regulated lncRNAs in NCI-H292 cells after stimulation with Dermatophagoides farinae extracts, as well as their target gene pathways, can provide insight to the etiology and pathogenesis of allergy.

The Allergic Rhinitis Clinical Investigator Collaborative (AR-CIC): verification of nasal allergen challenge procedures in a study utilizing an investigational immunotherapy for cat allergy

Background

The Allergic Rhinitis Clinical Investigator Collaborative (AR-CIC) is a network of experienced Allergic Rhinitis (AR) researchers developing better research tools based on the nasal allergen challenge (NAC). A key objective of such is the ability to detect efficacy in a small population. AR-CIC sought to test its NAC protocol as a secondary objective in two small mechanistic research trials of a novel form of immunotherapy [Cat Peptide Antigen Desensitisation (Cat-PAD)] for which efficacy had previously been demonstrated. The primary objective (not presented here) was to identify potential biomarkers of efficacy for peptide immunotherapy, and this provided an ideal opportunity to corroborate the NAC protocol. We aim to clinically validate the AR-CIC NAC methodology in a pooled analysis of secondary endpoints measured in two open label mechanistic studies of cat allergic participants treated with Cat-PAD.

Methods

Cat allergic AR sufferers with ongoing cat exposure were included. Participants had to demonstrate a total nasal symptom score (TNSS) of at least 8 (max 12) and/or achieve a reduction in peak nasal inspiratory flow (PNIF) of ≥ 50% during a screening titrated NAC. Eligible participants then underwent a baseline NAC visit with the allergen dose that produced a positive challenge at screening, followed by four monthly injections of 6 nmol Cat-PAD. A follow up NAC visit documented changes in nasal response 1 month following the completion of treatment.

Results

Nineteen subjects completed the study protocol in the two studies combined. Four injections of Cat-PAD resulted in a significant reduction in TNSS responses generated via NAC following allergen challenge (15 min p < 0.05, 30 min p < 0.05, 1 h p < 0.01, 2 h p < 0.05). There was modest correlation between symptom scores and PNIF measurements.

Conclusions

This study supports the validity of the AR-CIC’s optimised NAC protocol for conducting research of the potential efficacy of novel therapeutics in multi-centre studies.

Trial registration Both studies reported herein were registered clinicaltrials.gov (NCT01383590 and NCT01383603)

The dangerous liaison between pollens and pollution in respiratory allergy

OBJECTIVE

To recapitulate the more recent epidemiologic studies on the association of air pollution with respiratory allergic diseases prevalence and to discuss the main limitations of current approaches used to establish a link between pollinosis and pollution.

DATA SOURCES

Through the use of PubMed, we conducted a broad literature review in the following areas: epidemiology of respiratory allergic diseases, effect of pollution and climate changes on pollen grains, and immunomodulatory properties of pollen substances.

STUDY SELECTIONS

Studies on short- and long-term exposure to air pollutants, such as gaseous and particulate materials, on allergic sensitization, and on exacerbation of asthma symptoms were considered.

RESULTS

Trend in respiratory allergic disease prevalence has increased worldwide during the last 3 decades. Although recent epidemiologic studies on a possible association of this phenomenon with increasing pollution are controversial, botanic studies suggest a clear effect of several pollutants combined to climatic changes on the increased expression of allergenic proteins in several pollen grains. The current literature suggests the need for considering both pollen allergen and pollutant contents for epidemiologic evaluation of environmental determinants in respiratory allergies. We propose that a measure of allergenic potential of pollens, indicative of the increase in allergenicity of a polluted pollen, may be considered as a new risk indicator for respiratory health in urban areas.

CONCLUSION

Because public greens are located in strict proximity to the anthropogenic sources of pollution, the identification of novel more reliable parameters for risk assessment in respiratory allergic diseases is an essential need for public health management and primary prevention area.

Airway epithelium interactions with aeroallergens: role of secreted cytokines and chemokines in innate immunity

Airway epithelial cells are the first line of defense against the constituents of the inhaled air, which include allergens, pathogens, pollutants, and toxic compounds. The epithelium not only prevents the penetration of these foreign substances into the interstitium, but also senses their presence and informs the organism’s immune system of the impending assault. The epithelium accomplishes the latter through the release of inflammatory cytokines and chemokines that recruit and activate innate immune cells at the site of assault. These epithelial responses aim to eliminate the inhaled foreign substances and minimize their detrimental effects to the organism. Quite frequently, however, the innate immune responses of the epithelium to inhaled substances lead to chronic and high level release of pro-inflammatory mediators that may mediate the lung pathology seen in asthma. The interactions of airway epithelial cells with allergens will be discussed with particular focus on interactions-mediated epithelial release of cytokines and chemokines and their role in the immune response. As pollutants are other major constituents of inhaled air, we will also discuss how pollutants may alter the responses of airway epithelial cells to allergens.

Developments in the field of allergy in 2012 through the eyes of Clinical & Experimental Allergy

In 2012, we received 683 submissions and published 20 editorials, 38 reviews, 11 letters and 128 original articles. This represents an acceptance rate for original papers in the range of 20%. About 30% of original papers were triaged not to go out to review, either because the editors did not feel they had sufficient priority for publication or because the topic did not feel right for the readers of the journal. We place great emphasis on obtaining sufficient high-quality reviews to make our decisions on publication fair and consistent. Inevitably, however, there is a degree of luck about what gets published and which papers miss out, and we are always happy to receive an appeal on our decisions either at the triage stage or after review. This gives us the opportunity to revisit the decision and revise it or explain in more detail to the authors the basis for the decision. Once again in 2012, we were delighted by the quality of the papers submitted and the breadth and depth of research into allergic disease that it revealed. The pattern of papers submitted was similar in previous years with considerable emphasis on all aspects of asthma and rhinitis. We were particularly pleased with our special issue on severe asthma. Elucidating mechanisms using either animal models or patients has always been a major theme of the journal, and the excellent work in these areas has been summarized by Harissios Vliagoftis with a particularly interesting section on early-life events guiding the development of allergic disease, which understandably continue to be a major theme of research. Magnus Wickman summarized the papers looking at the epidemiology of allergic disease including work from birth cohorts, which are an increasingly rich source of data on risk factors for allergic disease, and two papers on the epidemiology of anaphylaxis. Giovanni Passalacqua discussed the papers in the clinical allergy section of the journal, and Adriano Mari who runs the excellent Allergome website discussed the papers looking at allergens including characterization and the relative usefulness of allergen arrays versus single extracts in diagnosis and management.

Gene expression analysis in allergology: the prediction of Hymenoptera venom allergy severity and treatment efficacy

Insect venom allergy (IVA) may result in the most severe systemic reactions seen in allergology. The only potentially curative treatment option is venom immunotherapy (VIT) over 3 to 5 years. This treatment is effective in more than 90% of subjects but no reliable predictors of VIT effectiveness exist. Sting challenge with a living insect can be performed to assess the effectiveness of VIT: the predictive value of sting challenge can be highly sensitive in patients with honeybee venom allergy whereas in yellow jacket allergy, a negative result can be reliable if the challenge has been repeated at least 3 times.

The analysis of gene expression may be a step towards personalized venom immunotherapy assessing the effectiveness of treatment, the minimal required time for VIT and the persistence of long term tolerance induced by the treatment. Recent studies have enabled construction of a predictive model that could potentially be used in clinical practice to assess the efficacy of insect venom immunotherapy. A set of 69 genes that may be responsible for long-term protection was identified. Further analysis of the previously identified 6 transcripts make up the 18 gene predictive peripheral blood showed differences in patients treated with IVA. Further studies are needed to investigate the usefulness of gene expression analysis and other markers in the prediction of VIT effectiveness.