Association of umbilical cord serum TARC/CCL17 with childhood allergies: A birth cohort study

The search for blood biomarkers useful in treating atopic dermatitis patients

INTRODUCTION

Atopic dermatitis (AD) is diagnosed based on clinical signs and symptoms as well as on a clinical course lacking distinct laboratory or histological features; however, the recent appearance of molecularly targeted drugs against AD urges us to try to discover and develop biomarkers useful for treating AD patients.

AREAS COVERED

This article commenced with a targeted PubMed search using 'atopic dermatitis' and 'biomarker' as keywords. We combined the findings from the B-PAD study that we have recently published and summarized data, particularly those recently published.

EXPERT OPINION

Many cells and molecules are listed as potential biomarkers of AD, most of which are type 2 mediators. Among them, CCL17/TARC is now thought to be the most reliable biomarker of AD. During the B-PAD study, we recently found that three biomarkers - squamous cell carcinoma antigen 2 (SCCA2), CCL26/eotaxin-3, and lactose dehydrogenase (LDH) - are better able than CCL17/TARC to assess the clinical severity and disease activity of AD. Moreover, although several biomarkers showed good ability to monitor the efficacy of molecularly targeted drugs against AD. More studies on the discovery and development of biomarkers of AD are awaited to refine treatments for AD patients.

Atopic dermatitis and food allergy: More than sensitization

The increased risk of food allergy in infants with atopic dermatitis (AD) has long been recognized; an epidemiologic phenomenon termed "the atopic march." Current literature supports the hypothesis that food antigen exposure through the disrupted skin barrier in AD leads to food antigen-specific immunoglobulin E production and food sensitization. However, there is growing evidence that inflammation in the skin drives intestinal remodeling via circulating inflammatory signals, microbiome alterations, metabolites, and the nervous system. We explore how this skin-gut axis helps to explain the link between AD and food allergy beyond sensitization.

Gut microbiome in the first 1000 days and risk for childhood food allergy

OBJECTIVE

To summarize recent data on the association between gut microbiome composition and food allergy (FA) in early childhood and highlight potential host-microbiome interactions that reinforce or abrogate oral tolerance.

DATA SOURCES

PubMed search of English-language articles related to FA, other atopic disease, and the gut microbiome in pregnancy and early childhood.

STUDY SELECTIONS

Human studies published after 2015 assessing the relationship between the gut bacteriome and virome in the first 2 years of life and FA or food sensitization development in early childhood were prioritized. Additional human studies conducted on the prenatal gut microbiome or other atopic diseases and preclinical studies are also discussed.

RESULTS

Children who developed FA harbored lower abundances of Bifidobacterium and Clostridia species and had a less mature microbiome during infancy. The early bacterial microbiome protects against FA through production of anti-inflammatory metabolites and induction of T regulatory cells and may also affect FA risk through a role in trained immunity. Infant enteric phage communities are related to childhood asthma development, though no data are available for FA. Maternal gut microbiome during pregnancy is associated with childhood FA risk, potentially through transplacental delivery of maternal bacterial metabolites, though human studies are lacking.

CONCLUSION

The maternal and infant microbiomes throughout the first 1000 days of life influence FA risk through a number of proposed mechanisms. Further large, longitudinal cohort studies using taxonomic, functional, and metabolomic analysis of the bacterial and viral microbiomes are needed to provide further insight on the host-microbe interactions underlying FA pathogenesis in childhood.

Factors contributing to the diagnosis and onset prediction of perennial allergic rhinitis in high-risk children: A sub-analysis of the CHIBA study

BACKGROUND

This study aimed to clarify the diagnostic and predictive factors for perennial allergic rhinitis (PAR) onset in children by analyzing the results of the Chiba High-risk Birth Cohort for Allergy study, which examined newborns with a family history of allergies.

METHODS

Overall, 306 pregnant women were recruited. Their newborns were examined by otolaryngologists and pediatric allergists at 1, 2, and 5 years of age. Participants with clinical and laboratory data available at all consultation points were considered eligible.

RESULTS

Among 187 eligible participants, the prevalence rates of PAR were 2.1%, 4.3%, and 24.1% at 1, 2, and 5 years of age, respectively. AR-specific nasal local findings and eosinophils in nasal smear were observed in a substantial number of patients with PAR at 1 and 2 years of age. Factors present up to 2 years of age that were associated with PAR onset at 5 years of age, in descending order, were as follows: sensitization to house dust mites (HDM), nasal eosinophilia, and sensitization to cat dander. In 44 cases with HDM sensitization, nasal eosinophilia up to 2 years of age achieved a sensitivity of 76.0% and a specificity of 73.7% for predicting PAR onset at 5 years.

CONCLUSIONS

Rhinitis findings and nasal eosinophilia are useful auxiliary diagnostic items for pediatric PAR. Sensitization to HDM and nasal eosinophilia were the most influential factors associated with future PAR onset. A combination of these factors may facilitate the prediction of PAR onset.

Skin Predictive Biomarkers for the Development of Atopic Dermatitis and Food Allergy in Infants

The pathogenesis of atopic dermatitis (AD) is multifactorial, involving a dynamic interplay between genetic susceptibility, skin-barrier dysfunction, microbiome alterations, and immune dysregulation, whereas food allergy (FA) arises from the interplay of transcutaneous sensitization to food allergens and failure in the induction of oral tolerance. Skin epicutaneous sensitization is commonly involved in the development of AD and FA. Although clinical trials have been conducted to prevent AD or FA by applications of emollients on the skin after birth, the results are not consistent. For more effective preventive strategies, reliable biomarkers are required to identify high-risk individuals. Skin tape stripping (STS) is a non-invasive technique for identifying these biomarkers in the skin. By analyzing the stratum corneum collected via STS, researchers can gain molecular or cellular insights into the early pathogenesis and potential progression of AD and FA. This review aims to elucidate the critical aspects of AD and FA, underlying their pathogenesis, early manifestations, and STS's potential as a tool for identifying predictive non-invasive biomarkers in infants prior to onset of clinical disease.