LAUSR

Background Atopic dermatitis (AD) is a chronic pruritic inflammatory dermatosis. Phosphodiesterases (PDEs) are a superfamily of enzymes that catalyse the hydrolysis of cyclic AMP (cAMP), a second messenger that controls key cellular functions, into its inactive forms. Selective inhibitors of PDE4, a cAMP-specific PDE, serve as potent antiinflammatory agents. Objectives To measure PDE4 gene expression in patients with AD before and after treatment with topical mometasone cream, in comparison to controls. Materials & Methods Twenty patients with acute and subacute AD were investigated. Skin biopsies before and after treatment were obtained for evaluation of PDE4 expression level by RT-PCR. Results The level of PDE4 mRNA was significantly higher in AD patients either before or after treatment compared to controls ( p < 0.001), and the level of PDE4 mRNA in AD patients significantly decreased following treatment ( p < 0.001). Conclusion Our study indicates that there is an increased level of PDE4 in AD lesions, suggesting that PDE4 plays an important role in the pathogenesis of AD. Targeting PDE4 (using PDE4 inhibitors) may herald a new era in the treatment of AD.