Faecal Eosinophilic Protein X (f-EPX), Atopic Dermatitis, Sensitisation and Gastrointestinal Permeability in Infants Aged 3-6 Months

Abstract

RATIONALE: Gastrointestinal (GI) inflammation has been implicated as a contributing factor in atopic dermatitis (AD) and has been reported in children with food allergies and AD. The role of faecal EPX in investigating and monitoring gastrointestinal inflammation associated with AD was studied. METHODS: Infants aged 3-6 months enrolled: AD-severity scored (SCORAD-Index), serum specific IgE, gastrointestinal permeability (Lactulose/Mannitol test) measured. Stool samples were collected from 239 infants (n=203 AD, n=36 healthy); extracts for f-EPX analysis were prepared as previously described (Peterson et al. 2002). Faecal-EPX was measured by UniCAP® (Pharmacia Diagnostics AB, Sweden). Data were log-transformed, results presented as geometric mean (GM) with 95% confidence intervals (95%CI). RESULTS: F-EPX levels significantly higher in infants with AD compared to healthy controls (GM 2506 ng/g [2146-2926] vs. 1635 ng/g [1193-2241]; p=0.032). F-EPX did not correlate with AD-severity (SCORAD-score). Sensitisation to food allergens was significantly associated with higher f-EPX levels (Sensitised 3200ng/g [1960-6463] vs. not sensitised 2050 ng/g [914-4725], p=0.021) and specific IgE levels to egg allergen correlated with f-EPX levels (R=0.26; p=0.005). Infants (AD or healthy) with normal gastrointestinal permeability had significantly lower f-EPX levels compared to those with increased permeability (normal permeability: 1252 ng/g [775-2034] vs. increased permeability 2409 ng/g [1305-5570]; p=0.012). CONCLUSIONS: Faecal EPX is high in infants with AD, sensitised infants and in infants with increased gastrointestinal permeability. This suggests increased eosinophilic inflammation in the gastrointestinal tract. F-EPX may be useful in monitoring the progression of gastrointestinal inflammation in these infants and further our understanding of underlying pathophysiological processes