Abstract: Objective To investigate the auxoaction and mechanism of CD11 c+DCs on psoriasis. Method：CD11 c+DCs in the psoriasis-like lesions were identified by immunofluorescence double staining experiments. The CD11 c+DCs were injected subcutaneously into the neck skin of transgenic mice without disease. The clinical features were observed and assessed with PASI score every day. The ear and back skin were HE stained. At the same time, the T lymphocyte and DCs of bone marrow, spleen, submandibular lymph nodes and blood were analyzed by flow cytometry, and the T lymphocyte in the skin lesions were analyzed by immunofluorescence. The heart, liver, spleen, lungs and kindey were HE stained. Results In the psoriasis-like lesions, about 90% FLT3+ cells expressed CD11c. HE test showed that the thickness of the skin layer was significant different between the experimental group (ear: 29±4 μm; back: 25±3 μm) and the control group(ear: 11±2 μm; back: 9±1 μm)（P<0.01）. CD3+CD4+ T lymphocyte cells in the blood of the experimental mice (17.87 %) were decreased significantly (P <0.01) compared with the control group mice (31.77 %). The numbers of Th1 and Th17 cells from bone marrow, spleen, submaxillary lymph nodes and blood, as the same as CD11 c+DCs from bone marrow and submaxillary lymph nodes, were decreased in the experimental mice compared with the control group mice (P <0.01). The number of CD4+T cells,CD8+T cells,IL-17a+cells and IFN-γ+cells in the skin lesions from the experimental group all were higher than that from the control group (P <0.01). And the vessels in the lesions of the experimental group were higher than that in the control group (P <0.01). Conclusion FLT3+CD11c+DCs may play an important role on the occurrence and development of psoriasis by increasing the T lymphocyte and the blood vessel in the skins of K14-VEGF transgenic mice.

Key words: Key word：FLT3+DCs, K14-VEGF transgenic mice, psoriasis, immune regulation