Toll-like receptor 2 in patients with atopic dermatitis

Abstract

Background Atopic dermatitis (AD) is one of the most frequent chronic inflammatory skin diseases that is often associated with a personal or a family history of asthma, allergic rhinitis, or conjunctivitis. One hallmark of AD is the striking susceptibility to colonization with Staphylococcus aureus. Toll-like receptors (TLRs) are a major class of pattern recognition receptors that are involved in detecting invading pathogens in the skin and initiating a cutaneous immune response. TLRs participate in cutaneous host defense mechanisms against various skin infections caused by common bacterial, fungal, and viral pathogens. Objectives The aims of this study are to examine the relation between the severity of the clinical features of AD and the expression of TLR2 and to evaluate the expression of TLR2 on peripheral blood monocytes of AD patients, and correlate it with serum IgE. Participants and methods Thirty patients with AD were included in this study (14 males and 16 females between 6 months and 26 years of age). All patients with AD fulfilled the diagnostic criteria of Hanifin and Rajka. They were examined clinically and the severity of eczema was assessed using the Nottingham Eczema Severity Score. Twenty-five healthy matched volunteers (15 males and 10 females) served as controls. Routine laboratory examinations were recorded, total serum IgE was determined using a chemiluminescent liquid-phase immunoassay, and TLR2 number on peripheral blood monocytes was determined by flow cytometry. Results There was no statistically significant difference in the level of expression of TLR2 on peripheral blood monocytes of patients with AD in either the intrinsic or the extrinsic groups compared with those of the controls. However, there was a highly statistically significant positive correlation between the TLR2 level and a personal history of other allergic diseases. Serum total IgE levels were elevated in 73.9% of patients with AD. Moreover, a highly significant positive correlation was found between serum IgE and the surface area score for AD. Conclusion TLR2 expression is related to a personal history of multiple allergic diseases rather than to AD alone. The serum IgE level is related to the surface area score for AD.