Deep phenotyping of infants and toddlers undergoing food oral immunotherapy (DINOSAUR): design and baseline characteristics of a prospective multi-omics cohort.

BACKGROUND: The mechanisms influencing successful outcomes of oral Immunotherapy (OIT) are poorly understood. This study investigates the role of environmental, microbial, genetic, and immunological factors on the effectiveness of OIT in infants. OBJECTIVES: To identify biological and environmental mechanisms associated with successful OIT in infants by characterizing longitudinal changes in the microbiome and other multi-omic markers and relating these changes to clinical treatment outcomes. METHODS: The Deep phenotypINg Of infantS And toddlers Undergoing food oral immunotheRapy (DINOSAUR) study is a prospective cohort study with two groups: infants (<18 months) undergoing OIT, and a comparison group (18-36 months) on the OIT waitlist. In the OIT group, biomaterial (blood, stool, urine, throat and skin swabs, skin tape strips, saliva, and nasal lining samples) and extensive information on environmental exposures has been collected at baseline immediately before initiation of OIT and ongoingly at the end of OIT (exit time-point), and has been collected once in the comparison group (age-matched to the exit time-point). Participant recruitment and sample collection were completed at BC Children's Hospital, Vancouver, Canada. Multi-omics analyses of the collected samples are ongoing and will be reported separately.The primary outcome is changes in the composition and functional profile of the oral- and gut microbiome during infant OIT. RESULTS: A total of 81 participants with suspicion of food allergy attending the BC Children's Hospital Allergy Clinic between March 2023 and November 2023 were included; 58 infants in the OIT group and 23 children in the age-matched comparison group awaiting OIT. Of the 58 infants, 5 turned out not to have an IgE-mediated allergy. Their samples were archived and regarded as "non-food allergic controls". In the infant group (n = 53), 66% were male, 85% had atopic dermatitis, and 42% were born by cesarean section. The majority (70%) were of Asian descent and lived in an urban environment (90%). The most common allergies were against peanut (51%), egg (40%) and cow's milk (26%). CONCLUSIONS: This prospective cohort study is the first of its kind to employ a systems biology approach to investigate how extensive biological and environmental factors influence OIT outcomes.