Faculty Bibliography

Food allergy is increasingly prevalent and poses a life-threatening risk to those afflicted. The health care costs associated with food allergies are also increasing. Current and emerging treatments for food allergies aim at protecting against reactions caused by accidental ingestion and increasing the food allergen reaction threshold, although this protection is often temporary. In the future, ideal biologic therapies would target key mediators of the type II immune pathway, essential in development of the atopic march to prevent development of food allergies. Biologics offering long-term protection against allergic reactions to food are needed, and several agents are already in development.

Skin barrier dysfunction has been reported in both atopic dermatitis (AD) and food allergy (FA). However, only one-third of patients with AD have FA. The purpose of this study was to use a minimally invasive skin tape strip sampling method and a multiomics approach to determine whether children with AD and FA (AD FA+) have stratum corneum (SC) abnormalities that distinguish them from AD without FA (AD FA-) and nonatopic (NA) controls. Transepidermal water loss was found to be increased in AD FA+. Filaggrin and the proportion of ω-hydroxy fatty acid sphingosine ceramide content in nonlesional skin of children with AD FA+ were substantially lower than in AD FA- and NA skin. These abnormalities correlated with morphologic changes in epidermal lamellar bilayer architecture responsible for barrier homeostasis. Shotgun metagenomic studies revealed that the nonlesional skin of AD FA+ had increased abundance of Staphylococcus aureus compared to NA. Increased expression of keratins 5, 14, and 16 indicative of hyperproliferative keratinocytes was observed in the SC of AD FA+. The skin transcriptome of AD FA+ had increased gene expression for dendritic cells and type 2 immune pathways. A network analysis revealed keratins 5, 14, and 16 were positively correlated with AD FA+, whereas filaggrin breakdown products were negatively correlated with AD FA+. These data suggest that the most superficial compartment of nonlesional skin in AD FA+ has unique properties associated with an immature skin barrier and type 2 immune activation.

Patients with severe atopic dermatitis (AD) are reported to represent between 10% and 18% of all patients with AD. However, in this subgroup of patients, quality of life is significantly affected and patients may have a number of atopic and nonatopic comorbidities. Treatment of this severe population has often been reactive with inappropriate use of systemic corticosteroids and unapproved immunosuppressants. Recent insights point to the systemic nature of AD, which has important therapeutic implications. Management of severe AD requires a comprehensive approach that incorporates proper diagnosis, assessment of disease severity, and impact on patient's and caregiver's quality of life, along with education regarding the chronic relapsing nature of the disease as well as treatment options. Biologics such as dupilumab offer a novel, targeted therapeutic approach for this systemic disease.

Mastocytosis is a clinically heterogenous disease characterized by mast cell hyperplasia in skin, bone marrow and/or visceral organs. Cutaneous mastocytosis is more frequently observed in children, whereas indolent systemic mastocytosis is more commonly observed in adults. Aggressive systemic presentation, particularly of the neonate, is exceptionally rare. We present a rare case of congenital aggressive systemic mastocytosis. The patient was a 37-week-old male, born by caesarean section owing to hepatosplenomegaly and ascites diagnosed in utero, who exhibited extensive cutaneous and systemic manifestations of mastocytosis at birth. Mutation analysis of c-KIT identified D816V mutation in exon 17. Although initial bilateral bone marrow aspirates demonstrated no mast-cell infiltrates or haematological neoplasm, subsequent bone-marrow biopsies postmortem exhibited multifocal mast-cell aggregates. Clinical course was complicated by bacteraemia and cardiorespiratory failure, leading to death at 10 weeks.