Genetic variants in Hippo pathway genes are associated with house dust mite-induced allergic rhinitis in a Chinese population

Background

House dust mite (HDM)‐induced allergic rhinitis (AR) is a highly prevalent disease with bothersome symptoms. Genetic variants of the Hippo pathway genes play a critical role in the respiratory disease. However, no study has reported associations between variants of the Hippo pathway genes and HDM‐induced AR risk.

Methods

Forty‐three key genes in the Hippo pathway were selected from the Kyoto Encyclopedia of Genes and Genomes (KEGG), Reactome pathway database, and previous reported studies. A case‐control study of 222 cases and 237 controls was performed to assess the associations between 121 genetic variants in these genes and HDM‐induced AR risk. DNeasy Blood & Tissues Kits were used for extracting genomic DNA from the venous blood and Infinium Asian Screening Array BeadChips for performing genotyping. A logistic regression model was applied to evaluate the effects of variants on HDM‐induced AR risk. The false discovery rate (FDR) method was utilized to correct for multiple testing. The receiver operating characteristic (ROC) curve was plotted to obtain the cut‐off value of total IgE for the diagnosis of HDM‐induced AR. Histone modification and transcription factor binding sites were visualized by UCSC genome browser. Moreover, expression qualitative trait loci (eQTL) analysis was obtained from Genotype‐Tissue Expression (GTEx) database.

Results

We found that rs754466 in DLG5 was significantly associated with a decreased HDM‐induced AR risk after FDR correction (adjusted odds ratio [OR] = 0.52, 95% confidence interval [CI] = 0.36–0.74, p = 3.25 × 10⁻⁴, P_FDR = 3.93 × 10⁻²). The rs754466 A allele reduced the risk of HDM‐induced AR in the subgroup of moderate/severe total nasal symptom score (TNSS). Furthermore, rs754466 was associated with a high mRNA expression of DLG5. Additionally, histone modification and transcription factor binding sites were rich in the region containing rs754466.

Conclusion

Our findings indicated that rs754466 in DLG5 decreased the susceptibility to HDM‐induced AR.

[Mite sensitization in children followed for respiratory allergy in a tropical African environment in Cotonou, Benin]

INTRODUCTION

In tropical Africa, allergies are not well documented. The objective of this work was to evaluate, by two methods, the sensitization to mites in children followed for respiratory allergy.

METHODS

Skin prick-test and IgE assay by REAST test with 3 mites: Dermatophagoides pteronyssinus (D. pteronyssinus), Dermatophagoides farinae (D. farinae) and Blomia tropicalis (B. tropicalis) were carried out in children from 3 to 15 years followed up for asthma and/or allergic rhinitis. The positive results of the two tests were compared.

RESULTS

Of the 130 (100%) children included, all eligible for the assay, 119 (91.5%) had the prick-test. The mean age and sex ratio (M/F) were 7±1 year, and 1.6. The association of rhinitis and asthma was the most frequent and found in 66 (55.6%). The sensitivity frequencies for the prick-test and assay were respectively 79% versus 36.1% for B. tropicalis, 71.4% versus 33.4% for D. pteronyssinus and 38.7% versus 37.8% for D. farinae. A moderate correlation between mean papule diameter and mean IgE concentration was observed.

CONCLUSION

In African tropical environments, dust mite sensitization in children followed for respiratory allergy is frequent, with the order of frequency being: B. tropicalis, D. pteronyssinus, and D. farinae. The prick-test had better sensitivity than the assay for its evaluation.

[Domestic exposure to moulds and mite allergens in Parisian patients]

INTRODUCTION

Moulds and mite allergens present in indoor environments are well known for their effects on respiratory health.

METHODS

From 2011 to 2015, the Paris Service for Environmental Health (SPSE) conducted investigations in 293 dwellings following medical referral. These audits included fungal analysis of air (in 12% of dwellings), in mattress surface and floor dust (24%), and mite allergen quantifications in mattresses and carpets (18%).

RESULTS

Indoor air fungal concentrations are not significantly different from those in outdoor air. When there is no ventilation or when the system is malfunctioning, an increase in indoor/outdoor air ratios is observed, indicating mould enrichment in the dwelling's indoor air. With regard to house dust samples, fungal spore concentrations vary according to the media from which samples were collected. Mattress fungal contamination is higher in dwellings where observed surface moulds exceed 1 per square meter. In the same way Der p1 mite allergens levels are greater in mattress dust in dwellings where mould contamination is visible.

CONCLUSIONS

This study describes the levels of contamination in the dwellings of Parisian patients.

[Blomia tropicalis: A house dust mite in the tropics]

INTRODUCTION

Blomia tropicalis is a mite that belongs to the superfamily of Glycyphagidae. Initially described as a storage mite, it is now considered as a house dust mite of tropical and sub-tropical areas.

STATE OF THE ART

Sensitization to this mite is very common in South America and Southeast Asia. Epidemiological studies have also found sensitization to this mite in Africa and Central America. Blo t 5 is the major allergen of B. tropicalis. Co-sensitization to other house dust mites such as Dermatophagoides pteronyssinus (Der p) and Dermatophagoides farinae (Der f) is very common. Cross-reactivity has been described but recombinant allergens revealed by molecular biology techniques do not explain this cross-reactivity. Sensitization to B. tropicalis seems to begin at the age of 36 months, the incidence increases until adulthood, and decreases from the age of 50. The involvement of B. tropicalis in allergic rhinitis and asthma is well described. It is also implicated in other allergic diseases. Few studies have assessed the therapeutic strategies available against this mite but immunotherapy is widely used.

PERSPECTIVES

Studies are needed to better understand the role of B. tropicalis in human diseases and to develop specific treatments.

[Sensitisation profile to airborne allergens of patients followed for asthma in Cotonou, Benin. A cross-sectional study using prick-tests]

RATIONALE

The sensitisation profile to airborne allergens of asthma patients followed in Benin is not known.

PATIENTS AND METHODS

A descriptive cross-sectional study was conducted from April to June 2013 at the hospital reference centre. A prick-test was performed in all adults with asthma consulting during this period. The standardized allergenic extracts tested were: mites (Dermatophagoides pteronyssinus [DP], Dermatophagoides farinae [DF] and Blomia tropicalis [BT]), cockroaches, 5 different grasses, Alternaria, dogs and cats. The test was positive when the diameter of the wheal was more than half that of the positive control and/or when the diameter of the wheal was ≥3mm than the negative control.

RESULTS

Of the 253 asthmatics tested, 247 (97.6%) had at least one positive skin reaction. The average age was 44 years, the sex ratio was 0.81. Sensitization to mites was the most frequent (99.6%), followed by cockroaches (71.3%), 5 grasses (71.3%), Alternaria (71%), dog (68%) and cat (63.6%). The average number of sensitivities was 5±2.

CONCLUSION

Asthmatics monitored in Cotonou have multiple sensitisations dominated by mites.

[Medical indoor environment counsellor (MIEC) in Burgundy: evaluation by physicians and patients]

Since December 2009, chest physicians and allergologists in Burgundy have been able to call upon a medical indoor environment counsellor (MIEC). The consultations are free for the patient and are undertaken following a medical referal after systematic cutaneous prick tests.

AIMS

To describe the indications, the distribution of prescriptions and to measure the impact of the counsellor's visits on the first 100 patients at 6 months and on the physicians at 18 months.

METHOD

Telephone interviews with the 67 physicians (whether prescribers or not) concerning their motivation and/or expectations, and with the first 100 patients concerning follow up of the recommendations.

RESULTS

Seventy percent of the physicians replied (n=47). The satisfaction of prescribers (n=22) was 8.42/10. The indications were rhinitis and a poorly controlled asthma. The requests concerned the search for dust mite (50%) and moulds (46%). Eighty-four percent of the physicians discussed the MIEC's report with the patients. The patients' symptoms were rhinitis (79%), asthma (57%) and conjunctivitis (33%). The Acarex test(®), performed in cases of positive prick tests to house dust mites (n=72), was strongly positive for 67 patients. Sixteen mould samples out of 21 were above the standard concentrations. Sixty-nine patients had followed the recommendations of the MIEC.

CONCLUSION

The impact of the MIEC visits was perceived as positive by the physicians and the patients. The medico-economic impact warrants further evaluation.