Lymphocyte expression of CD4+CD25hi and adhesion molecules in children with Atopic dermatitis: the effect of Levocetirizine treatment

There is considerable evidence that several novel H1 antihistamines possess anti-allergic/ anti-inflammatory properties, through inhibition of leukocyte activation. Levocetirizin and other H1 antihistamines are considered central to the treatment of atopic dermatitis (AD) associated pruritis; however there is a lack of studies of possible anti-inflammatory effect of these drugs in children with AD. In this study, we investigated the lymphocyte sub-population profile in the peripheral blood of 15 children with AD at baseline and following two weeks of levocetirizine treatment. The clinical symptoms and flow cytometric analysis of the percentage expression of CD4+CD25+ subsets on T cells, as well as expression of the adhesion molecules; CD4+CD54+ (ICAM-I) and CD4+CD62+ (L-Selectin) on T cells were evaluated. The children exhibited a reduction in the percentages of the eosinophil count (p<0.05) as well as major clinical symptoms, itching/ scratching (p<0.05) and the subsequent bleeding of lesions (p<0.05); however the total symptom score was not significantly changed. A significant increase was observed in CD4+CD25hi Treg cells while CD4+CD54+ (ICAM-I) cells were significantly decreased, and no significant change was observed in other populations. Reduction of CD4+CD54+ may be associated with suppression of IgE production and hence reduced mast cell recruitment into the inflammatory sites, on the other hand; expansion of CD4+CD25hi indicates that Treg-mediated host immune defenses are augmented. Our study suggests the potential of the anti-inflammatory effects of levocetirizine in allergic inflammation.