Abstract: Objective To investigate the effects of psoria tic lesional keratinocytes on development and differentiation of monocytes into L angerhans cells(LCs)so as to analyze the mechanism of abnormality of LCs in patients with psoriasis.Methods Monocytes isolated from normal peripheral blood were cultured with granulocyte/macrophage colony-stimulating factor(GM-CSF),interleukin-4(IL-4),transforming growth factorβ1(TGF-β1)and supernatants from healthy or pso riatic lesional keratinocytes for 5days.Their phenotypes,phagocytic capacity were analyzed by FACS calibur.Their immunostimula tory capacity was detected by mixed lymphocytes reaction(MLR).Results The phenotypes,phagocytic capacity and immunostimulatory capacity we re almost uniform in PBMC-derived LCs cultured with GM-CSF,IL-4,TGF-β1 in combination with supernatants from keratinocytes between psoriatic lesions and normal controls.Conclusions In this experiment,no significant difference is observed in the effects of healthy and psoriatic lesional keratinocytes on development and differentiation of monocytes into LCs.The data sugge st that the abnormalities of LCs in patients with psoriasis might not take place in the stage of LC differentiation.

Key words: Psoriasis, Keratinocytes, Langerhans cells, Cell differentiation