Can Faecal Eosinophil Cationic Protein and β-Defensin-2 Levels Be Useful in the Diagnosis and Follow-Up of Infants with Milk-Protein-Induced Allergic Proctocolitis?

OBJECTIVE

The aim of our study was to investigate whether faecal concentrations of eosinophil cationic protein (fECP) and human β-defensins (HBD2s) are significantly elevated in children with cow's milk-protein-induced allergic colitis (MPIAP) and whether a monthly milk-free diet reduces these markers.

MATERIALS AND METHODS

This was a single-centre, prospective, observational cohort study involving 70 infants with MPIAP, aged 1-3 months, and 30 healthy controls of the same age. The concentrations of fECP and HBD2 were measured using the ELISA method (IDK Eosinophil Cationic Protein and β-Defensins ELISA Kit, Immunodiagnostik AG, Germany). Diagnosis of MPIAP was confirmed with an open milk challenge test.

RESULTS

The concentrations of fECP and HBD2 proved useful in evaluating MPIAP treatment with a milk-free diet, where the resolution of allergy symptoms and a significant ( = 0.0000) decrease in the concentrations of both biomarkers were observed after 4 weeks of following the diet. The concentrations of fECP and HBD2 were still higher than those in the control group. High concentrations of fECP can be helpful in diagnosing MPIAP (100% sensitivity), but the low specificity of the assay means that there is a risk of diagnosing MPIAP in one in six children who do not have the disease. The concentrations of HBD2 have low sensitivity, so one in four children with MPIAP will not be confirmed to have the disease using this indicator.

CONCLUSIONS

fECP and HBD2 can be used to monitor the resolution of colitis in infants with MPIAP treated with a milk diet, indicating a slower resolution of allergic inflammation than the resolution of allergic symptoms. Therefore, neither of the parameters are useful for the diagnosis of MPIAP.