Expression of Fc receptors for IgG during acute and chronic cutaneous inflammation in atopic dermatitis

Atopic dermatitis is an allergic skin disease characterized by elevated tot al and antigen-specific serum IgE and IgG4 levels. In acute and chronic cut aneous inflammation, large cellular infiltrates including T cells, dendriti c cells and macrophages are found, especially in the dermis, These cells pl ay an important part in the regulation of local inflammatory reactions. Rec eptors binding IgG (Fc gamma R) are involved in dendritic cell and macropha ge function. In this study, we examined the in vivo distribution and cellul ar expression of the three classes of leucocyte Fc gamma R in human skin du ring acute and chronic cutaneous inflammation in atopic dermatitis. Atopy p atch test skin was used as a model for acute inflammation in atopic dermati tis, while chronic lesional skin was used to investigate Fc gamma R express ion in chronically inflamed skin. In atopy patch test sites no increase in the number of CD1a+ dendritic cells and a slight increase in macrophages co mpared with non-lesional skill was observed. Our results showed increased e xpression of Fc gamma RI (CD64) and Fc gamma RIII (CD16) in acutely inflame d skin as well as in chronically inflamed lesional skin, compared with heal thy and non-lesional atopic dermatitis skin. Fc gamma RI was expressed by R FD1+, RFD7+ and CD68+, but not by CD1a+ dermal dendritic cells. RFD1+ dendr itic cells and CD68+ macrophages were the main Fc gamma RIII-expressing cel ls during the acute inflammatory reaction, The significant increase in expr ession of Fc gamma RIII (CD16) and Fc gamma RI (CD64) probably results from upregulation of the receptors on resident cells. insight into the presence of Fc gamma R+ cells in human skin during inflammation is important both f or our understanding of skin immune reactions and the development of new th erapeutic concepts.