Selected eosinophil proteins as markers of inflammation in atopic dermatitis patients

Atopic dermatitis (AD) is an inflammatory skin disease characterized by chronic and recurrent course, beginning primarily in early childhood. The etiopathogenesis of AD has not yet been fully understood, although various types of inflammatory cells including eosinophils may be involved in its pathomechanism. The basic aim of the study was to evaluate the usefulness of selected eosinophil proteins in serum and urine of AD patients, as markers of disease severity. The study also aimed to analyze correlations between the level of examined proteins and parameters such as skin prick test (SPT) results, serum concentration of total IgE, and coexistence of symptoms of other atopic diseases. The study included 30 AD patients and two control groups: 30 patients suffering from chronic urticaria and 30 healthy individuals. The mean level of eosinophil proteins measured in serum and urine of AD patients was higher than that in controls, although a significant difference was only recorded for serum and urine level of eosinophil protein X (EPX). Patients with very severe/severe AD presented higher levels of eosinophil proteins than patients presenting with mild/moderate AD, although no significant difference was found between these two groups. AD patients with positive SPT results and detectable specific IgE in serum, and with coexisting symptoms of other atopic diseases presented with higher mean levels of serum and urine eosinophil proteins than AD cases with negative SPT results and without any symptoms of other atopic diseases. In children suffering from AD, serum eosinophil cationic protein level, EPX level and urine EPX level were higher than those in healthy children, however, without statistical significance. Study results suggested a significant role of eosinophils in the etiopathogenesis of AD. Serum and urine levels of selected eosinophil proteins may serve as an important part of diagnostic approach to AD patients, especially in differentiation of allergic and non-allergic forms of AD. The results are also promising for the usefulness of selected eosinophil proteins in the diagnosis of AD in children, however, thorough analysis on a larger group of patients is needed.