# Association of myeloid cell reactivity patterns with safe food predictions in FPIES patients

## TL;DR

This study introduces a new method to predict safe foods for FPIES patients by analyzing immune cell reactions, reducing food reactions and improving dietary diversity.

## Contribution

The study introduces individual-specific myeloid cell reactivity patterns (iMCRPs) as a novel diagnostic tool for predicting safe food ingestion in FPIES patients.

## Key findings

- Foods that do not trigger immune cell responses in FPIES patients are safe to ingest with 98.5% accuracy.
- Using iMCRPs reduced new food reaction rates from 19.5% to 0% and increased dietary diversity.
- A 9-gene panel was identified to represent FPIES ex vivo immune responses.

## Abstract

Food protein-induced enterocolitis syndrome (FPIES) is an understudied non-IgE-mediated food allergy, which is distinct from and lacks diagnostic testing akin to IgE testing. FPIES affects infants and toddlers but can persist into adulthood. As there are no extant methods to identify safe foods for FPIES patients, food ingestion trials are performed at home and often lead to reactions and development of food aversions, which may lead to failure-to-thrive and gastric feeding tube requirements. We hypothesized that foods that fail to elicit responses in immune cells of FPIES patients would be safe to ingest, which could support development of a diagnostic method to headstart safe food identification in patients.

We developed an ex vivo model of FPIES using food-stimulated white blood cells (WBCs) from pediatric FPIES patients and controls by defining a 9-gene panel representative of FPIES ex vivo responses and conducted a single-arm pilot clinical trial.

Myeloid cells of FPIES patients displayed variable individual-specific myeloid cell reactivity patterns (iMCRPs) to different foods. Foods that failed to elicit repsonses in patients’ immune cells were safe to ingest with a negative predictive value of 98.5%. This, when utilized in prospective predictions, reduced newly introduced food reaction rates from 19.5 to 0% while increasing food repertoire diversity.

iMCRPs represent a novel and potentially useful tool that associates with safe food ingestion in FPIES patients for foods that fail to elicit immune cell reactions.

Trial Registration The trial has been registered at registered at ClinicalTrials.gov # NCT04644783.

The online version contains supplementary material available at 10.1186/s13223-025-00968-1.