Administration of poly(I:C) improved dermatophagoides farinae-induced atopic dermatitis-like skin lesions in NC/Nga mice by the regulation of Th1/Th2 balance

Atopic dermatitis (AD) is characterized by a chronic and replapsing skin disease with Th2-dominant allergic inflammation. Poly(I:C) has been shown to have immunopotentiator properties, but its effect on AD has not been examined. In this study, the immunomodulatory effects of poly(I:C), using dermatophagoides farinae (Df)-induced AD-like skin lesions in NC/Nga mice, were investigated. The clinical scores were reduced significantly by the treatment with poly(I:C) at 25 and 50 μg/mouse. Histological analysis of the skin also revealed that treatment of poly(I:C) at 25 and 50 μg/mouse significantly reduced the inflammatory cellular infiltrate, including mast cells and eosinophils. Moreover, poly(I:C) increased the level of IFN-γ, a Th1 cytokine, whereas decreasing that of selective Th2 cytokine both in vivo and in vitro. The levels of serum IgE and Th2 chemokines such as eotaxin, TARC, in spleen cells were also reduced by poly(I:C). These results suggest that poly(I:C) inhibit the development of Df-induced AD-like skin lesions in NC/Nga mice through regulation of the Th1/Th2 balance. Therefore, our results indicate that poly(I:C) might be a useful immunomodulatory agent for the treatment of human AD.