A Study on the Evaluation of the Staphylococcal Exotoxins and Staphylococcal Enterotoxin A-specific IgE Antibody in Childhood Atopic Dermatitis

Yim, Yong Soon; Park, Chun Wook; Lee, Cheol Heon; Song, Won Keun

Abstract

BACKGROUND: The skin of patients with atopic dermatitis (AD) exhibits a striking susceptibility to colonization with Staphylococcus aureus (S. aureus). Superantigenic exotoxins produced by S. aureus and their specific IgE antibodies are thought to be important precipitating factors of AD, but there are few reports evaluating these 2 factors at the same time. OBJECT: Our purpose was to examine whether the isolation of S. aureus colonies and the presence of the exotoxins from the skin of childhood AD patients and the level of anti-staphylococcal enterotoxin A(SEA) IgE antibody in their sera correlated with their severity of AD.
METHODS
Thirty patients with mild-to-severe AD, 2 to 15 years of age, were evaluated by using SCORAD index. S. aureus was isolated from lesional and non-lesional skin of AD patients, and from healthy controls. By using reversed passive latex agglutination toxin detection kits, we examined whether staphylococcal exotoxins could be detected. Anti-SEA IgE antibody was determined by using AlaSTAT(R)assay.
RESULTS
S. aureus colonizations were found in 11(36.7%) of the lesional skin and in 5(16.7%) of the non-lesional skin of 30 AD patients. Staphylococcal exotoxins were detected in 5(45.5%) of the 11 colonizations from lesional skin and in 2(40%) of the 5 colonizations from non-lesional skin. SEA was most frequently detected. S. aureus colonization was correlated with the severity of AD. However, there were no statistical significances between severity of AD and others such as exotoxin production, and the level of total IgE and anti-SEA IgE. Total IgE level was significantly higher in the group of exotoxin production, and correlated with the level of anti-SEA IgE.
CONCLUSION
The correlation between S. aureus colonization and severity of AD in our study might support the role of S. aureus in patients with AD. On the other hand, it could be considered that exacerbation of AD trigger more colonization of S. aureus by way of disruption of skin barrier function from scratching or reduced immune responses needed for defense against bacteria. Although there was no correlation between AD severity and exotoxin production and the level of anti-SEA IgE in this study, staphylococcal exotoxins and their specific IgE antibodies might play a role at least in a subset of AD patients.